Conjugated diene polymer, method for producing conjugated diene polymer, conjugated diene polymer composition, and rubber composition

Abstract

The present invention relates to a conjugated diene polymer, a method for producing a conjugated diene polymer, a conjugated diene polymer composition, and a rubber composition. The purpose of the present invention is to provide a conjugated diene polymer which has extremely excellent processability when made into a sulfide, and which has excellent wear resistance, handling stability, and breaking strength after being made into a sulfide. A conjugated diene-based polymer which is a copolymer of a conjugated diene compound and an aromatic vinyl compound, and which has a Mooney viscosity measured at 100 DEG C of 40-170, a Mooney stress relaxation rate measured at 100 DEG C of 0.239-0.35, and a branching degree (Bn) of 8 or more as determined by a GPC-light scattering measurement method with a viscosity detector, and which contains a nitrogen atom.

Description

[0001] This application is a divisional application. The international application number of the original application is PCT / JP2020 / 032175, the international application date is August 26, 2020, the Chinese national application number is 202080061016.7, the date of entry into China is February 28, 2022, and the name of the invention is "Conjugated diene polymers, methods for producing conjugated diene polymers, conjugated diene polymer compositions and rubber compositions". Technical Field

[0002] The present invention relates to a conjugated diene polymer, a method for producing a conjugated diene polymer, a conjugated diene polymer composition and a rubber composition. Background Art

[0003] There has been an increasing demand for lower fuel consumption in automobiles, and there has been a demand for improvements in rubber materials used in automobile tires, particularly in tire treads that come into contact with the road surface.

[0004] In recent years, as the fuel efficiency regulations for automobiles have become stricter, automobiles have become lighter in weight by using resin components, and with regard to tires, there has been a demand for thinner tire components from the perspective of weight reduction.

[0005] In order to reduce the weight of the tire, it is particularly necessary to reduce the thickness of the tread portion which comes into contact with the road surface and has a high material ratio. In this tread portion, it is more required than ever to use a rubber material having excellent wear resistance.

[0006] Furthermore, in order to reduce energy loss caused by the tire during driving, the rubber material used for the tire tread is required to have low rolling resistance, that is, a material with low hysteresis loss.

[0007] On the other hand, from the viewpoint of safety, it is required to have excellent handling stability and wet skid resistance and sufficient breaking strength for practical use.

[0008] Examples of rubber materials that meet the above requirements include rubber compositions containing a rubber-like polymer and a reinforcing filler such as carbon black or silica.

[0009] It is known that when a rubber composition containing silica is used, the balance between low hysteresis loss and wet skid resistance can be improved. In addition, the following attempts have been made: the dispersibility of silica in the rubber composition is improved by introducing a functional group having affinity or reactivity with silica into the molecular terminal of a rubber-like polymer with high mobility, and then the mobility of the molecular terminal of the rubber-like polymer is reduced by bonding with silica particles, thereby reducing hysteresis loss and improving wear resistance and breaking strength.

[0010] For example, Patent Documents 1 to 3 propose compositions of a modified conjugated diene polymer and silicon oxide, wherein the modified conjugated diene polymer is obtained by reacting an amino group-containing alkoxysilane with an active terminal of the conjugated diene polymer.

[0011] Furthermore, Patent Document 4 proposes a modified conjugated diene polymer obtained by subjecting an active terminal of a polymer to a coupling reaction with a polyfunctional silane compound.

[0012] Prior art literature

[0013] Patent Literature

[0014] Patent Document 1: Japanese Patent Application Publication No. 2005-290355

[0015] Patent Document 2: Japanese Patent Application Laid-Open No. 11-189616

[0016] Patent Document 3: Japanese Patent Application Publication No. 2003-171418

[0017] Patent Document 4: International Publication No. 07 / 114203 Pamphlet Summary of the invention

[0018] Problems to be solved by the invention

[0019] However, compared to carbon black having a hydrophobic surface, silicon oxide has a hydrophilic surface, and therefore, due to its low affinity with the conjugated diene polymer, silicon oxide has a disadvantage that its dispersibility in the composition is inferior to that of carbon black. Therefore, in the composition containing silicon oxide, in order to provide bonding between silicon oxide and the conjugated diene polymer and improve the dispersibility in the composition, it is necessary to separately contain a silane modifier or the like.

[0020] In addition, when a functional group highly reactive with silicon oxide is introduced into the molecular terminal of a conjugated diene polymer, the following tendency of deterioration in processability is observed: during the kneading step, the reaction with silicon oxide particles occurs, and kneading becomes difficult due to increased viscosity of the composition; or when a sheet is formed after kneading, surface roughness easily occurs or the sheet is easily broken.

[0021] Furthermore, when such a composition is made into a sulfide, particularly when it is made into a sulfide containing an inorganic filler such as silicon oxide, the balance between wear resistance and low hysteresis loss and wet skid resistance is insufficient.

[0022] Therefore, an object of the present invention is to provide a conjugated diene polymer having extremely excellent processability when produced as a vulcanizate and having excellent abrasion resistance, handling stability and breaking strength after being produced as a vulcanizate.

[0023] Means for solving problems

[0024] The present inventors have conducted intensive studies to solve the problems of the above-mentioned prior art and have found that a conjugated diene copolymer having a Mooney viscosity and a Mooney stress relaxation rate measured at 100° C. within a specific range and a degree of branching (Bn) within a specific range has extremely excellent processability when produced as a vulcanizate and has excellent wear resistance, handling stability and breaking strength after being produced as a vulcanizate, thereby completing the present invention.

[0025] That is, the present invention is as follows. [1]

[0027] A conjugated diene polymer, wherein:

[0028] The Mooney viscosity measured at 100°C is 40 or more and 170 or less.

[0029] The Mooney stress relaxation rate measured at 100°C is less than 0.35.

[0030] The degree of branching (Bn) determined by GPC-light scattering measurement with a viscosity detector is 8 or more. [2]

[0032] The conjugated diene polymer as described in [1], wherein the degree of branching (Bn) of the polymer having the highest absolute molecular weight among at least two absolute molecular weights when the height in the absolute molecular weight curve is 1 / 2 of Hi (1 / 2Hi), based on the height of the peak top in the absolute molecular weight curve obtained by GPC-light scattering measurement using a viscosity detector (wherein, when there are multiple peak tops in the above-mentioned absolute molecular weight curve, it is the height of the peak top with the largest absolute molecular weight) Hi, is 12 or more. [3]

[0034] The conjugated diene polymer as described in [1] or [2], wherein the conjugated diene polymer contains a nitrogen atom. [4]

[0036] The conjugated diene polymer according to any one of [1] to [3], wherein the modification rate measured by column adsorption GPC method is 60% by mass or more. [5]

[0038] The conjugated diene polymer according to any one of [1] to [4], wherein the polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a main chain branch structure. [6]

[0040] The conjugated diene polymer according to any one of [1] to [5], wherein

[0041] The polymer has a star-shaped polymer structure with more than three branches.

[0042] At least one branch of the star-shaped structure has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a further main chain branch structure. [7]

[0044] The conjugated diene polymer as described in [5] or [6], wherein

[0045] The moiety derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group is a monomer unit based on a compound represented by the following formula (1) or (2),

[0046] The polymer chain has branching points derived from monomer units based on the compound represented by the following formula (1) or (2).

[0047] [Chemistry 1]

[0048]

[0049] [Chemistry 2]

[0050]

[0051] (In formula (1), R 1 It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a part of it may have a branched structure.

[0052] R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure.

[0053] When there are multiple R 1 ~R 3 Each one is independent.

[0054] X 1 represents an independent halogen atom.

[0055] m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3.)

[0056] (In formula (2), R 2 ~R 5Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure. 2 ~R 5 Each one is independent.

[0057] X 2 ~X 3 represents an independent halogen atom.

[0058] m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3. ) [8]

[0060] The conjugated diene polymer described in [7] has a monomer unit based on a compound represented by the above formula (1), wherein R 1 is a hydrogen atom, m=0. [9]

[0062] The conjugated diene polymer as described in [7] has a monomer unit based on a compound represented by the above formula (2), wherein m=0 and b=0.

[10]

[0064] The conjugated diene polymer as described in [7] has a monomer unit based on a compound represented by the above formula (1), wherein R 1 It is a hydrogen atom, m=0, l=0, n=3.

[11]

[0066] The conjugated diene polymer as described in [7] has a monomer unit based on a compound represented by the above formula (2), wherein m=0, l=0, n=3, a=0, b=0, and c=3.

[12]

[0068] A method for producing a conjugated diene polymer, which is the method for producing a conjugated diene polymer according to any one of [1] to

[11] , comprising the following steps:

[0069] a polymerization and branching step, using an organic lithium compound as a polymerization initiator, polymerizing at least a conjugated diene compound while adding a branching agent to obtain a conjugated diene polymer having a main chain branch structure; and

[0070] In the coupling step, the conjugated diene polymer is coupled with a coupling agent.

[13]

[0072] A conjugated diene polymer composition comprising 100 parts by mass of the conjugated diene polymer according to any one of [1] to

[11] and 1 to 60 parts by mass of a rubber softener.

[14]

[0074] A rubber composition comprising a rubber component and 5.0 parts by mass or more and 150 parts by mass or less of a filler relative to 100 parts by mass of the rubber component.

[0075] The rubber component contains 10 parts by mass or more of the conjugated diene polymer described in any one of [1] to

[11] or the conjugated diene polymer composition described in

[13] , based on 100 parts by mass of the total amount of the rubber component.

[0076] Effects of the Invention

[0077] According to the present invention, a conjugated diene polymer can be obtained which has extremely excellent processability when preparing a vulcanizate, has particularly excellent abrasion resistance and handling stability after preparing a vulcanizate, and has a breaking strength sufficient for practical use. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] Figure 1 This is a schematic diagram showing an example of the relationship between the absolute molecular weight curve obtained by the GPC-light scattering measurement method with a viscosity detector and the branching degree distribution.

[0079] Explanation of symbols

[0080] A…branching degree of a polymer of 1 / 2Hi, B…schematic diagram of the branching degree distribution of a main chain branched polymer (a distribution with more branches as the molecular weight increases compared to the average of the entire polymer), C…schematic diagram of the branching degree distribution of a simple star branch (a distribution that is basically constant and depends on the number of functions of the modifier). DETAILED DESCRIPTION

[0081] A specific embodiment of the present invention (hereinafter referred to as “this embodiment”) will be described in detail below.

[0082] It should be noted that the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be implemented by appropriately modifying the present invention within the scope of the gist thereof.

[0083] [Conjugated diene polymer]

[0084] The conjugated diene polymer of this embodiment has a Mooney viscosity of 40 to 170 measured at 100°C, a Mooney stress relaxation rate of 0.35 or less measured at 100°C, and a degree of branching (hereinafter also referred to as "Bn") of 8 or more determined by GPC-light scattering measurement with a viscosity detector.

[0085] The conjugated diene polymer having the Mooney viscosity, Mooney stress relaxation ratio and degree of branching (Bn) measured at 100° C. defined as above has extremely excellent processability when made into a vulcanizate, excellent wear resistance and handling stability after being made into a vulcanizate, and has a practically sufficient breaking strength.

[0086] In the conjugated diene polymer of the present embodiment, by arbitrarily adjusting the amount of vinyl bonds and the amount of aromatic vinyl compounds in the conjugated diene bond units on the basis of limiting the Mooney viscosity, Mooney stress relaxation rate and degree of branching (Bn) measured at 100° C., the processability when preparing a sulfide is extremely excellent, the abrasion resistance and handling stability after preparing the sulfide are excellent, and the glass transition temperature (hereinafter also referred to as “Tg”) of the conjugated diene polymer can be arbitrarily adjusted while maintaining a practically sufficient breaking strength.

[0087] For example, by setting the vinyl bond content and the aromatic vinyl compound content in the conjugated diene bond unit to be low, the Tg of the conjugated diene polymer can be lowered, and there is a tendency to obtain a rubber composition having improved wear resistance and breaking strength after being made into a vulcanizate, and further excellent low hysteresis loss properties.

[0088] Furthermore, by increasing the vinyl bond content and the aromatic vinyl compound content in the conjugated diene bond units, the Tg of the conjugated diene polymer can be increased, and the processability when preparing a vulcanizate can be improved, and a rubber composition having excellent wet skid resistance tends to be obtained.

[0089] (Mooney viscosity)

[0090] As described below, the conjugated diene polymer of the present embodiment is a structure that limits the degree of branching (Bn). Generally, when compared with a linear polymer with the same molecular weight, the molecular size of the polymer with a branched structure tends to decrease. Thus, in the polystyrene-converted molecular weight obtained by gel permeation chromatography (hereinafter also referred to as "GPC") determination (which is a method of screening using the molecular size of the polymer and relatively comparing it with a standard polystyrene sample), the molecular weight of the polymer with a branched structure tends to be evaluated too small.

[0091] In addition, compared with the polystyrene-equivalent molecular weight determined by gel permeation chromatography (GPC) measurement, the absolute molecular weight determined by the GPC-light scattering method with a viscosity detector directly observes the size of the molecule using the light scattering method and measures the molecular weight (absolute molecular weight). Therefore, it is not affected by the structure of the polymer or the interaction with the column filler, and tends to be able to accurately measure the molecular weight without affecting the polymer structure such as the branching structure of the conjugated diene polymer. However, it is easily affected by the detection method of the light scattering detector, and although it is effective for relative comparison under specific measurement conditions, it is difficult to determine the true structure of the conjugated diene polymer.

[0092] On the other hand, Mooney viscosity is an index showing the comprehensive characteristics of a conjugated diene polymer, including information on the molecular weight, molecular weight distribution, degree of branching, and content of a softener of the conjugated diene polymer. In addition, in the determination method of Mooney viscosity, the error of the measured value based on mechanical error specified in ISO289 is also very small, and it is extremely effective in controlling the performance of a conjugated diene polymer.

[0093] As described above, in general, viscosity can also be regarded as an index that replaces molecular weight. In contrast, it is difficult to accurately grasp the molecular weight under certain circumstances. Therefore, as one of the technical features of the conjugated diene polymer of the present embodiment, the inventors set the Mooney viscosity. More specifically, in the conjugated diene polymer of the present embodiment, the Mooney viscosity (hereinafter also referred to as "ML") measured at 100°C is 40 or more and 170 or less as a technical feature, but usually in the region near the lower limit, even when the molecular weight is simply reduced to adjust the ML, or a softener (oil, etc.) is added to adjust the ML, it is difficult to make the Mooney stress relaxation rate (hereinafter also referred to as "MSR") measured at 100°C be less than 0.35. By making the degree of branching (Bn) 8 or more (adjusting the type and amount of branching agent, and adjusting the type and amount of coupling agent), it is easy to achieve an MSR of less than 0.35.

[0094] That is, in order to obtain a conjugated diene polymer that exhibits desired performance, it is not sufficient to simply control the molecular weight or the Mooney viscosity. Therefore, from the perspective of improving the elastic modulus of the composition, it has been found that by combining factors such as increasing the degree of branching (adjusting the type and amount of branching agent added, and adjusting the type and amount of coupling agent added), the elastic modulus (rigidity) of the vulcanizate can be increased without impairing the processability of the composition, thereby improving the handling stability.

[0095] In the conjugated diene polymer of the present embodiment, from the perspectives of productivity of the conjugated diene polymer, processability after being made into a composition mixed with a filler, etc., and wear resistance, handling stability and breaking strength after the composition is vulcanized, the Mooney stress relaxation rate and degree of branching (Bn) described below are within specific ranges, and the Mooney viscosity measured at 100° C. is preferably 40 to 170, more preferably 50 to 150, and even more preferably 55 to 130.

[0096] When the Mooney viscosity measured at 100°C is 40 or more, the wear resistance and breaking strength of the sulfide after being made tend to be improved; in addition, when the Mooney viscosity measured at 100°C is 170 or less, the situation in which obstacles occur in the production of conjugated diene polymers can be suppressed, and the processability is good when preparing a composition mixed with a filler, etc.

[0097] For the conjugated diene polymer of the present embodiment, in order to adjust the Mooney viscosity to the above-mentioned range, it can be a conjugated diene polymer composition comprising more than 1 mass part and less than 60 mass parts of the rubber softener described later relative to 100 mass parts of the conjugated diene polymer. In the case of manufacturing a polymer by continuous polymerization, oil etc. are usually utilized for filling, and by filling, the Mooney viscosity is reduced, and the Mooney stress relaxation rate increases. The inventor focuses on the situation that the processability of the polymer can be more properly controlled than the state of the polymer single substance by limiting the state completed after filling, therefore considering that in the case of adding a softener to complete, the Mooney viscosity should be determined in the state containing a softener, and is defined as above.

[0098] In the measurement of Mooney viscosity, a sample of a conjugated diene polymer is pressed into a plate shape and placed in an apparatus. The sample is first preheated at 100°C for 1 minute, and then the rotor is rotated at 2 rpm. The torque is measured after 4 minutes, and the measured value is taken as the Mooney viscosity (ML). (1+4) ). More specifically, it can be measured by the method described in the examples described later.

[0099] (Mooney stress relaxation rate)

[0100] The conjugated diene polymer of the present embodiment preferably has a Mooney stress relaxation rate (hereinafter also referred to as "Mooney stress relaxation rate" or "MSR") of 0.35 or less measured at 100° C. The Mooney stress relaxation rate is also affected by the molecular weight, molecular weight distribution, degree of branching, and content of the softener of the conjugated diene polymer, similarly to the Mooney viscosity, and is an index representing the comprehensive characteristics of the conjugated diene polymer.

[0101] The conjugated diene polymer of the present embodiment has a Mooney viscosity measured at 100° C. within a specific range of 40 to 170, a degree of branching (Bn) described below of 8 or more, and a Mooney stress relaxation rate measured at 100° C. of 0.35 or less.

[0102] Generally, when the Mooney viscosity is reduced by reducing the molecular weight, reducing the degree of branching, or increasing the amount of rubber softener added, the Mooney stress relaxation rate tends to increase, making it difficult to achieve the Mooney stress relaxation rate defined in the present application.

[0103] The Mooney stress relaxation rate is an index of the molecular entanglement of the conjugated diene copolymer. The lower the Mooney stress relaxation rate is, the more entanglement there is in the molecules. It is an index of the branching structure and the molecular weight.

[0104] For example, when comparing conjugated diene polymers having the same Mooney viscosity, the more branches a conjugated diene polymer has, the smaller the MSR becomes. Therefore, the MSR in this case can be used as an indicator of the degree of branching.

[0105] In conjugated diene polymers, in order to make the Mooney stress relaxation rate below 0.35, it is effective to control the molecular structure in a manner that improves weight-average molecular weight, increases high molecular weight components, thereby expands molecular weight distribution, improves the degree of branching. For example, in conjugated diene polymers, if the Mooney viscosity is made to be more than 40 and the degree of branching (Bn) described later is made to be more than 8, the Mooney stress relaxation rate tends to be less than 0.35. The Mooney stress relaxation rate can be controlled by the addition of a polymerization initiator, the functional number of a branching agent, the addition of a branching agent, the functional group number of a coupling agent or a nitrogen-containing modifier, the addition of a coupling agent or a nitrogen-containing modifier.

[0106] For example, by reducing the amount of polymerization initiator added to increase the molecular weight of the conjugated diene polymer before coupling, adding a branching agent with a large number of functional groups, and coupling using a coupling agent with a large number of functional groups or a nitrogen-containing modifier, there is a tendency to obtain a conjugated diene polymer with a Mooney viscosity of 40 or more, a degree of branching (Bn) of 8 or more, and a Mooney stress relaxation rate of 0.35 or less.

[0107] The conjugated diene polymer of the present embodiment has a Mooney stress relaxation rate measured at 100° C. of 0.35 or less, preferably 0.32 or less, more preferably 0.30 or less, and further preferably 0.28 or less. The lower limit of the Mooney stress relaxation rate is not particularly limited and may be less than the detection limit, and is preferably 0.05 or more.

[0108] By making the Mooney stress relaxation rate 0.35 or less, when a composition mixed with a filler or the like is prepared, the filler such as silicon oxide is well inserted into the conjugated diene polymer, thereby tending to make the composition show good processability. In addition, when the composition is made into a sulfide, there is a tendency that the elastic modulus of the sulfide is particularly increased, and there is a tendency that a composition with excellent handling stability, wear resistance, and excellent breaking strength can be obtained.

[0109] MSR can be measured using a Mooney viscometer as follows.

[0110] The measurement temperature of Mooney stress relaxation rate is set at 100°C. First, the sample is preheated for 1 minute, and then the rotor is rotated at 2 rpm. The torque after 4 minutes is measured, and the Mooney viscosity (ML) is measured based on the torque. (1+4) ), then immediately stop the rotation of the rotor, record the torque in Mooney units every 0.1 seconds from 1.6 seconds to 5 seconds after stopping, make a double logarithmic plot of the torque and time (seconds), find the slope of the straight line at this time, and take its absolute value as the Mooney stress relaxation rate (MSR).

[0111] More specifically, it can be measured by the method described in Examples below.

[0112] In order to make the Mooney stress relaxation rate 0.35 or less, the molecular structure is controlled in such a way as to increase the weight average molecular weight, increase the high molecular weight component to broaden the molecular weight distribution, and increase the branching degree.

[0113] For example, in a conjugated diene polymer, if the Mooney viscosity is more than 40 and the degree of branching (Bn) is more than 8, there is a tendency that the Mooney stress relaxation rate is less than 0.35. In addition, in order to make the Mooney stress relaxation rate less than 0.30, for example, if the Mooney viscosity of the conjugated diene polymer is more than 60 and the degree of branching (Bn) is more than 8, the Mooney stress relaxation rate tends to be less than 0.30. In addition, the degree of branching can be controlled by, for example, the functional number of the branching agent, the addition amount of the branching agent, the functional group number of the coupling agent or the nitrogen-containing modifier, the addition amount of the coupling agent or the nitrogen-containing modifier.

[0114] (Degree of branching (Bn))

[0115] In the conjugated diene polymer of the present embodiment, the degree of branching (Bn) determined by GPC-light scattering measurement with a viscosity detector (hereinafter also referred to as the degree of branching (Bn)) is 8 or more from the viewpoint of processability, abrasion resistance and breaking strength.

[0116] The branching degree (Bn) of 8 or more means that the number of side chain polymer chains is 8 or more on the substantially longest polymer main chain of the conjugated diene polymer of the present embodiment.

[0117] The degree of branching (Bn) of the conjugated diene polymer is defined as g'=6Bn / {(Bn+1)(Bn+2)} using a contraction factor (g') measured by GPC-light scattering method with a viscosity detector.

[0118] Generally, when compared with a linear polymer having the same absolute molecular weight, the molecular size of a polymer having branches tends to be smaller.

[0119] The shrinkage factor (g') is an index of the ratio of the size occupied by a molecule relative to a linear polymer assuming the same absolute molecular weight. That is, as the degree of branching of the polymer increases, the shrinkage factor (g') tends to decrease.

[0120] Regarding the shrinkage factor, in this embodiment, the intrinsic viscosity is used as an index of the molecular size, and the linear polymer is set to comply with the intrinsic viscosity [η] = -3.883M 0.771 In the above formula, M is the absolute molecular weight.

[0121] However, the shrinkage factor shows the rate of decrease in molecular size and does not accurately reflect the branching structure of the polymer.

[0122] Therefore, the branching degree (Bn) of the conjugated diene polymer is calculated using the value of the contraction factor (g') at each absolute molecular weight of the conjugated diene polymer. The calculated "branching degree (Bn)" accurately represents the number of polymers directly or indirectly bonded to each other on the longest main chain structure.

[0123] The calculated degree of branching (Bn) is an index showing the branch structure of the conjugated diene polymer. For example, in the case of a common four-branched star polymer (four polymer chains connected in the center), two polymer chain arms are connected to the longest high-branch main chain structure, and the degree of branching (Bn) is evaluated as 2.

[0124] In the case of a common 8-branched star polymer, 6 polymer chain arms are bonded to the longest high-branch main chain structure, and the branching degree (Bn) is evaluated as 6.

[0125] In the conjugated diene polymer of the present embodiment, the degree of branching (Bn) is 8 or more, which means that the modified conjugated diene polymer has the same branches as the 10-branched star polymer structure as the star polymer structure.

[0126] Here, "branch" refers to a structure formed by direct or indirect bonding with other polymers relative to one polymer. In addition, "branching degree (Bn)" refers to the number of polymers directly or indirectly bonded to each other on the longest main chain structure.

[0127] When the degree of branching (Bn) is 8 or more, the conjugated diene polymer of the present embodiment has extremely excellent processability when it is made into a sulfide, and the sulfide has excellent abrasion resistance and breaking strength.

[0128] Generally, as the absolute molecular weight increases, the processability tends to deteriorate. When the absolute molecular weight increases in a linear polymer structure, the viscosity during the production of the sulfide increases significantly, and the processability deteriorates significantly.

[0129] Therefore, even if a large number of functional groups are introduced into the polymer to improve the affinity and / or reactivity with silicon oxide mixed as a filler, the silicon oxide cannot be fully dispersed in the polymer during the kneading process. As a result, the functions of the introduced functional groups cannot be exerted, and the effects of low hysteresis loss and improved anti-slip properties brought about by the introduction of the functional groups that should be expected cannot be exerted.

[0130] On the other hand, in the conjugated diene polymer of the present embodiment, by limiting the degree of branching (Bn) to 8 or more, the increase in viscosity during the production of sulfide accompanied by the increase in absolute molecular weight can be greatly suppressed, so that, for example, it can be fully mixed with silicon oxide and the like in the kneading process, and silicon oxide can be dispersed around the conjugated diene polymer. As a result, for example, the wear resistance and breaking strength can be improved by setting the molecular weight in the conjugated diene polymer to a large extent, and silicon oxide can be dispersed around the polymer by sufficient kneading, and the functional group can act and / or react, thereby enabling it to have practically sufficient low hysteresis loss and wet skid resistance.

[0131] The absolute molecular weight of the conjugated diene polymer can be measured by the method described in the examples below.

[0132] The degree of branching (Bn) of the conjugated diene polymer of the present embodiment is 8 or more, preferably 10 or more, more preferably 12 or more, and even more preferably 15 or more.

[0133] A conjugated diene polymer having a degree of branching (Bn) within this range tends to have excellent processability when a vulcanizate is produced.

[0134] The upper limit of the degree of branching (Bn) is not particularly limited and may be equal to or higher than the detection limit, but is preferably 84 or lower, more preferably 80 or lower, further preferably 64 or lower, and still more preferably 57 or lower.

[0135] When the degree of branching (Bn) of the conjugated diene polymer of the present embodiment is 84 or less, the polymer tends to have excellent wear resistance after being converted into a vulcanizate.

[0136] The degree of branching of the conjugated diene polymer can be controlled to be above 8 by the combination of the amount of branching agent added and the amount of terminal coupling agent added. Specifically, the degree of branching can be controlled by the number of functional groups of the branching agent, the amount of branching agent added, the timing of adding the branching agent, the number of functions of the coupling agent or the modifier containing nitrogen atoms, and the amount of the coupling agent or the modifier containing nitrogen atoms. More specifically, as described in the method for producing the conjugated diene polymer described below.

[0137] (Degree of branching in the macromolecular region (Bn))

[0138] In the conjugated diene polymer of the present embodiment, the degree of branching (Bn) of the polymer with the highest absolute molecular weight among at least two absolute molecular weights when the height in the absolute molecular weight curve is 1 / 2 of the height (1 / 2Hi) of Hi is preferably 12 or more, based on the height of the peak top in the absolute molecular weight curve obtained by GPC-light scattering measurement method with a viscosity detector (wherein, when there are multiple peak tops in the above-mentioned absolute molecular weight curve, it is the height of the peak top with the largest absolute molecular weight) Hi. In other words, the degree of branching (Bn) of the polymer of 1 / 2Hi being 12 or more means that the degree of branching in the high molecular weight region is high relative to the average degree of branching (Bn) of the above-mentioned polymer chain as a whole, and the conjugated diene polymer has a degree of branching distribution. It should be noted that in the above-mentioned absolute molecular weight curve, there are at least two 1 / 2Hi on the low molecular weight side and the high molecular weight side of the peak top. Regarding "the polymer with the highest absolute molecular weight among at least two absolute molecular weights at a height (1 / 2Hi) of 1 / 2 of the height Hi of the peak top", when there are two 1 / 2Hi on the low molecular weight side and the high molecular weight side of the peak top, it refers to the polymer when the absolute molecular weight is 1 / 2Hi on the high molecular weight side. In addition, when there are multiple peaks and multiple 1 / 2Hi on the high molecular weight side of the peak top, it refers to the polymer when the absolute molecular weight is 1 / 2Hi with the highest absolute molecular weight.

[0139] Figure 1 This is a schematic diagram showing an example of the relationship between the absolute molecular weight curve obtained by the GPC-light scattering measurement method with a viscosity detector and the branching degree distribution.

[0140] Generally, in the case of a conjugated diene polymer having a simple star structure in which one of the active ends of the conjugated diene polymer is coupled with a coupling agent or a coupling agent having a nitrogen atom-containing group, a condensation reaction based on a part of the coupling agent residue is performed, such as Figure 1As shown, although some changes are observed in the degree of branching (Bn) in the region with a higher molecular weight than the molecular weight of the polymer of 1 / 2Hi (hereinafter also referred to as the "high molecular weight region"), there is a tendency that the degree of branching (Bn) in the high molecular weight region is basically constant depending on the functional number of the coupling agent.

[0141] That is, when a star structure is introduced by coupling at the polymerization terminal, although the degree of branching (Bn) in the high molecular weight region can be increased to a certain extent, the method of controlling the degree of branching (Bn) in the high molecular weight region by condensation of coupling agent residues makes it difficult to make the condensation reaction proceed uniformly, and the Mooney viscosity also fluctuates after the completion of polymerization, which is not preferred from the perspective of quality control of the obtained conjugated diene polymer.

[0142] On the other hand, in the conjugated diene polymer of this embodiment when the degree of branching (Bn) of the polymer of 1 / 2Hi is 12 or more, Figure 1 As shown, regarding the branching degree distribution of the main chain branched polymer, it can be seen that the higher the molecular weight is compared with the average of the entire polymer, the higher the branching is.

[0143] The conjugated diene polymer of the present embodiment is preferably a conjugated diene polymer with a preferred branching distribution in which the degree of branching (Bn) of the polymer of 1 / 2Hi is 12 or more, specifically, for example, it is preferably a conjugated diene polymer in which each polymer chain constituting the star structure is a further branched structure. Such a conjugated diene polymer with a preferred branching distribution can be obtained, for example, by the following method without particular limitation. In a state where a branched structure is pre-introduced into a part of the polymer chain with an active end, a coupling reaction is carried out using a coupling agent (preferably a group containing a nitrogen atom), thereby being able to obtain a conjugated diene polymer with a degree of branching (Bn) in the high molecular weight region higher than the functional number of the coupling agent, and having an extended degree of branching distribution on the high molecular weight side compared to the peak of the molecular weight distribution.

[0144] A conjugated diene polymer having a high degree of branching (Bn) in the high molecular weight region means, for example, that the proportion of the conjugated diene polymer having a branched structure in the main chain in the high molecular weight region is high and the coupling efficiency by the coupling agent is high.

[0145] The degree of branching (Bn) of the polymer of 1 / 2Hi and the degree of branching (Bn) of the polymer in the high molecular weight region can be controlled by the number of functional groups of the branching agent, the amount of the branching agent added, the timing of the addition of the branching agent, and the functional number of the coupling agent or the modifier containing nitrogen atoms, and the amount of the coupling agent or the modifier containing nitrogen atoms. In the conjugated diene polymer of the present embodiment, the height of the peak in the absolute molecular weight curve obtained by the GPC-light scattering determination method with a viscosity detector (wherein, when there are multiple peaks in the above-mentioned absolute molecular weight curve, the height of the peak with the largest absolute molecular weight) Hi is used as a reference, and the degree of branching (Bn) of the polymer with the highest absolute molecular weight among at least 2 absolute molecular weights when the height in the absolute molecular weight curve is 1 / 2 of the height (1 / 2Hi) of Hi is preferably 12 or more, more preferably 15 or more, further preferably 18 or more, and particularly preferably 20 or more. In the conjugated diene polymer of the present embodiment, the upper limit of the degree of branching (Bn) of the polymer of 1 / 2Hi is not particularly limited, for example, 98 or less.

[0146] In the present embodiment, the degree of branching (Bn) of the polymer of 1 / 2Hi can be measured by the method described in the Examples described later.

[0147] The conjugated diene polymer of the preferred structure of the branching degree (Bn) being 8 or more and having a branching degree (Bn) of the polymer of 1 / 2Hi being 12 or more has a tendency of low melt viscosity, and in the mixing process under high temperature and high shear conditions, the processability when the compound is obtained by adding silicon oxide, etc. is very excellent. Generally, compared with the polymer of linear structure, when compared with the same molecular weight, the polymer with many branches has a tendency of obvious viscosity reduction in the high shear domain and easy mixing (good processability). It is believed that this is because, although the polymer with many branches is a high molecular weight, the molecular weight of each chain of the base polymer is small. It can be said that by increasing the branching degree in the high molecular weight region to a branching degree (Bn) of 1 / 2Hi polymer of 12 or more, the effect brought about by shortening each base polymer can be more significantly obtained. In order to improve the wear resistance and breaking strength, it is preferred to increase the molecular weight, but the viscosity of the polymer increases and it is difficult to mix with fillers, etc., which often becomes a limiting factor in designing a high molecular weight. However, as described above, by increasing the degree of branching in the high molecular weight region to a degree of branching (Bn) of the polymer of 1 / 2Hi of 12 or more, good processability is obtained, and with this, the room for increasing the molecular weight is increased. That is, a conjugated diene polymer having a high degree of branching in the high molecular weight region as large as a degree of branching (Bn) of the polymer of 1 / 2Hi of 12 or more has good processability when a compound is obtained, so it is possible to design a conjugated diene polymer with a high molecular weight, and there is a tendency to easily obtain a conjugated diene polymer with excellent wear resistance and breaking characteristics after being made into a sulfide.

[0148] (coupling)

[0149] The conjugated diene polymer of the present embodiment is preferably a conjugated diene polymer obtained by coupling the conjugated diene polymer obtained through polymerization and branching steps with a trifunctional or higher-functional reactive compound (hereinafter also referred to as a "coupling agent") at the active end of the conjugated diene polymer.

[0150] In the coupling step, a coupling agent or a coupling agent having a nitrogen atom-containing group is used to couple one end of the active terminal of the conjugated diene polymer to obtain the conjugated diene polymer. More specifically, as described in the method for producing the conjugated diene polymer described below.

[0151] (Coupling agent)

[0152] In this embodiment, the coupling agent used in the coupling step may have any structure as long as it is a trifunctional or higher-functional reactive compound, and is preferably a trifunctional or higher-functional reactive compound having a silicon atom. More specifically, it is as described in the method for producing a conjugated diene polymer described below.

[0153] The conjugated diene polymer of the present embodiment preferably contains a nitrogen atom. The conjugated diene polymer containing a nitrogen atom can be obtained, for example, by a coupling reaction using a modifying agent having a nitrogen atom-containing group described below.

[0154] (Modifier having a nitrogen atom-containing group)

[0155] The conjugated diene polymer of the present embodiment is more preferably a conjugated diene polymer obtained by coupling the active end of the conjugated diene polymer obtained through the polymerization and branching steps using a trifunctional or higher-functional reactive compound having a nitrogen atom-containing group (hereinafter also referred to as a "modifier having a nitrogen atom-containing group") to the conjugated diene polymer.

[0156] In the coupling step, a coupling reaction is performed on one of the active terminals of the conjugated diene polymer using a coupling agent having a nitrogen atom-containing group to obtain a conjugated diene polymer.

[0157] The modified conjugated diene polymer obtained by coupling using a modifier having a nitrogen atom-containing group has good dispersibility of silicon oxide after being mixed with a filler etc. to form a composition, good processability of the composition formed by mixing with a filler etc., and good wear resistance and breaking strength after the composition is made into a sulfide, and has a tendency to significantly improve the balance between low hysteresis loss and wet skid resistance. More specifically, as described in the method for producing a conjugated diene polymer described below.

[0158] Examples of the modifier having a nitrogen atom-containing group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen-containing carbonyl compounds, nitrogen-containing vinyl compounds, nitrogen-containing epoxy compounds, and the like.

[0159] The modifier having a nitrogen atom-containing group preferably has a nitrogen atom-containing functional group, and the nitrogen atom-containing functional group is preferably an amine compound having no active hydrogen, for example, a tertiary amine compound, a protected amine compound in which the above active hydrogen is substituted with a protecting group, an imine compound represented by the general formula -N=C, and an alkoxysilane compound bonded to the above nitrogen atom-containing group. More specifically, as described in the method for producing a conjugated diene polymer described below.

[0160] (Modification rate)

[0161] In the present specification, the “modification ratio” refers to the mass ratio of the conjugated diene polymer having a nitrogen atom-containing functional group relative to the total amount of the conjugated diene polymer.

[0162] For example, when a nitrogen-containing modifier is reacted with a terminal end, the mass ratio of the conjugated diene polymer having a nitrogen-containing functional group based on the nitrogen-containing modifier to the total amount of the conjugated diene polymer is expressed as the modification rate.

[0163] On the other hand, when a polymer is branched using a branching agent containing a nitrogen atom, the resulting conjugated diene polymer also has a nitrogen atom-containing functional group, and therefore the branched polymer is also included in the calculation of the modification ratio.

[0164] That is, in this specification, the total mass ratio of the coupled polymer based on the modifying agent having a nitrogen atom-containing functional group and / or the branched polymer based on the branching agent having a nitrogen atom-containing functional group is referred to as the "modification ratio".

[0165] In the conjugated diene polymer of the present embodiment, at least one end is modified with a nitrogen atom-containing group, thereby having a tendency to significantly improve the balance between low hysteresis loss and wet skid resistance while maintaining the processability after compounding a filler etc. to form a composition, and the wear resistance and breaking strength after the composition is made into a sulfide.

[0166] In the conjugated diene polymer of the present embodiment, from the aspects of processability, wear resistance, breaking strength, and the balance between low hysteresis loss and anti-wet skid resistance, the modification rate measured by column adsorption GPC method (hereinafter also referred to as "modification rate") is preferably 60% by mass or more relative to the total amount of the conjugated diene polymer.

[0167] The modification rate is preferably 65% ​​by mass or more, more preferably 70% by mass or more, further preferably 75% by mass or more, and still more preferably 80% by mass or more. The upper limit of the modification rate is not particularly limited, and is, for example, 98% by mass.

[0168] The modification rate can be measured by a chromatography method capable of separating modified components containing a functional group from non-modified components.

[0169] Examples of a method using this chromatography include a method using a gel permeation chromatography column filled with a polar substance such as silicon oxide that adsorbs specific functional groups and performing quantitative determination by comparison with an internal standard of a non-adsorbed component (column adsorption GPC method).

[0170] More specifically, the adsorption amount on the silica column is measured from the difference between the chromatogram obtained by measuring a sample solution containing the sample and low molecular weight internal standard polystyrene using a polystyrene gel column and the chromatogram obtained by measuring using a silica column, thereby obtaining the modification rate.

[0171] More specifically, the modification ratio can be measured by the method described in Examples.

[0172] In the conjugated diene polymer of the present embodiment, the modification ratio can be controlled to 60% by mass or more by adjusting the amount of the modifier added and the reaction method.

[0173] For example, the following methods can be combined to control the polymerization conditions, thereby achieving the above-mentioned modification rate: a method of using an organic lithium compound having at least one nitrogen atom in the molecule described later as a polymerization initiator to carry out polymerization; a method of copolymerizing a monomer having at least one nitrogen atom in the molecule; a method of using a modifier of the structural formula described later.

[0174] In the conjugated diene polymer of the present embodiment, from the aspect of the balance between processability and abrasion resistance, it is preferred that the conjugated diene polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a main chain branch structure; and more preferably, the conjugated diene polymer is a conjugated diene polymer having a star-shaped polymer structure with three or more branches, and has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group on at least one branch of the star structure, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a further main chain branch structure.

[0175] The "star-shaped polymer structure" as used herein refers to a structure in which a plurality of polymer chains (arms) are linked via one central branch point.

[0176] In addition, the one central branch point mentioned here has a substituent containing an atom derived from a coupling agent or a nitrogen atom derived from a modifier.

[0177] The "main chain branch structure" as used herein means a structure in which a polymer chain forms a branch point at a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and a polymer chain (arm) extends from the branch point.

[0178] In the conjugated diene polymer of the present embodiment, from the perspective of increasing the degree of branching (Bn), the main chain branching points composed of the part derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group are preferably 4 or more, and the branch structure derived from the star-shaped polymer structure formed by the coupling agent in the reaction step is preferably 3 or more, more preferably 4 or more, and further preferably 8 or more.

[0179] It should be noted that, when modification is performed using a star-shaped coupling agent and when a branching agent is introduced into the polymer, the degree of branching (Bn) increases, but when the coupling agent is used to branch the entire polymer chain, the contribution to the degree of branching (Bn) is greater.

[0180] In the design of the polymer, the degree of branching (Bn) can be controlled by selecting a coupling agent and selecting the type and amount of the branching agent, but by also taking the contribution rate into consideration, the control of the degree of branching (Bn) becomes easier.

[0181] (Main chain branch structure)

[0182] The main chain branch structure has two or more branching points, preferably three or more branching points, and more preferably four or more branching points, as measured by the branching points of the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group.

[0183] The branching point forming the main chain branch structure preferably has at least two polymer chains, more preferably has three or more non-main chain polymer chains, and even more preferably has four or more non-main chain polymer chains.

[0184] In particular, in the main chain branch structure formed by a vinyl monomer containing an alkoxysilyl group or a halosilyl group, 29 When the signal was detected by Si-NMR, a peak derived from the main chain branch structure was detected in the range of -45 ppm to -65 ppm, and more specifically in the range of -50 ppm to -60 ppm.

[0185] (Star-shaped polymer structure)

[0186] The conjugated diene polymer of the present embodiment preferably has a star polymer structure, and the number of branches derived from the star polymer structure is preferably 3 or more, more preferably 4 or more, further preferably 6 or more, and still more preferably 8 or more.

[0187] Regarding the method for obtaining a modified conjugated diene polymer (which is a conjugated diene polymer having a star-shaped polymer structure with more than three branches, having a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group on at least one branch of the star-shaped structure, and having a further main chain branch structure on the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group) as the conjugated diene polymer of the present embodiment, the above-mentioned "star-shaped polymer structure" can be formed by adjusting the number of functional groups of the coupling agent and the amount of the coupling agent added, and the "main chain branch structure" can be controlled by adjusting the number of functional groups of the branching agent, the amount of the branching agent added, and the timing of adding the branching agent.

[0188] In order to obtain a conjugated diene polymer (which is a conjugated diene polymer having a star-shaped polymer structure with more than three branches, wherein at least one branch of the star-shaped structure has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group has a further main chain branch structure), for example, the following method can be cited: polymerization is carried out using an organic lithium compound as a polymerization initiator, a branching agent that provides specific branching points is further added during or after the polymerization, the polymerization is continued, and then modification is carried out using a modifier that imparts a specific branching rate.

[0189] Such means for controlling polymerization conditions are described in the production method in the examples described later.

[0190] (Detailed structure of the main chain branch structure)

[0191] In the conjugated diene polymer of the present embodiment, it is preferred that the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group is a monomer unit based on a compound represented by the following formula (1) or (2), and that the polymer chain has branching points brought about by the monomer unit based on the compound represented by the following formula (1) or (2). It is more preferred that the conjugated diene polymer is obtained using a coupling agent, and it is further preferred that the conjugated diene polymer is a modified conjugated diene polymer in which at least one end of the conjugated diene polymer is modified with a nitrogen atom-containing group.

[0192] [Chemistry 3]

[0193]

[0194] [Chemistry 4]

[0195]

[0196] (In formula (1), R 1 It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a part of it may have a branched structure.

[0197] R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure. 1 ~R 3 Each one is independent.

[0198] X 1 represents an independent halogen atom.

[0199] m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3.)

[0200] (In formula (2), R 2 ~R 5 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure.

[0201] When there are multiple R 2 ~R 5 Each one is independent.

[0202] X 2 ~X 3 represents an independent halogen atom.

[0203] m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.

[0204] (m+n+l) means 3.

[0205] a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3.)

[0206] The conjugated diene polymer of the present embodiment is preferably a conjugated diene polymer having a monomer unit based on a compound represented by the above formula (1), wherein R 1 is a hydrogen atom, and m = 0. This increases the number of branches, thereby achieving the effect of improving wear resistance and processability.

[0207] The conjugated diene polymer of the present embodiment is preferably a conjugated diene polymer having a monomer unit based on a compound represented by the above formula (2), wherein m = 0 and b = 0. This can improve wear resistance and processability.

[0208] In addition, the conjugated diene polymer of the present embodiment is preferably a modified conjugated diene polymer having a monomer unit based on a compound represented by the above formula (2), wherein m = 0, l = 0, n = 3, a = 0, b = 0, and c = 3. This can improve wear resistance and processability.

[0209] The conjugated diene polymer of the present embodiment is more preferably a conjugated diene polymer having a monomer unit based on a compound represented by the above formula (1), wherein R 1 is a hydrogen atom, m = 0, l = 0, n = 3. This can increase the modification rate and branching degree, thereby improving fuel efficiency, wear resistance and processability.

[0210] (Branching Agent)

[0211] In the conjugated diene polymer of the present embodiment, when constructing a main chain branch structure, it is preferable to use a branching agent represented by the following formula (1) or formula (2) as a branching agent.

[0212] [Chemistry 5]

[0213]

[0214] [Chemistry 6]

[0215]

[0216] (In formula (1), R 1 It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a part of it may have a branched structure.

[0217] R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure.

[0218] When there are multiple R 1 ~R 3 Each one is independent.

[0219] X 1 represents an independent halogen atom.

[0220] m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.

[0221] (m+n+1) means 3.)

[0222] (In formula (2), R 2 ~R 5 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure.

[0223] When there are multiple R 2 ~R 5 Each one is independent.

[0224] X 2 ~X 3 represents an independent halogen atom.

[0225] m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.

[0226] (m+n+l) means 3.

[0227] a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3.)

[0228] In this embodiment, from the perspective of polymerization sustainability and increasing the degree of branching, the branching agent used to construct the main chain branch structure of the conjugated diene polymer is preferably R of formula (1): 1 A compound in which m is a hydrogen atom and m=0.

[0229] In the present embodiment, from the viewpoint of increasing the degree of branching, the branching agent used when constructing the main chain branch structure of the conjugated diene polymer is preferably a compound wherein m=0 and b=0 in formula (2).

[0230] In this embodiment, from the perspective of polymerization sustainability and improving the modification rate and branching degree, the branching agent used when constructing the main chain branch structure of the conjugated diene polymer is more preferably R of formula (1): 1 A compound wherein m=0, l=0, and n=3 is a hydrogen atom.

[0231] In addition, in this embodiment, from the perspective of improving the modification rate and branching degree, the branching agent used when constructing the main chain branch structure of the conjugated diene polymer is preferably a compound with m=0, l=0, n=3, a=0, b=0, and c=3 in the above formula (2).

[0232] Examples of the branching agent represented by the above formula (1) include, but are not limited to:

[0233] Trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane,

[0234] Tripropoxy (4-vinylphenyl) silane, tributoxy (4-vinylphenyl) silane, triisopropoxy (4-vinylphenyl) silane,

[0235] Trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane,

[0236] Tripropoxy (3-vinylphenyl) silane, tributoxy (3-vinylphenyl) silane, triisopropoxy (3-vinylphenyl) silane,

[0237] Trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane,

[0238] Tripropoxy (2-vinylphenyl) silane, tributoxy (2-vinylphenyl) silane, triisopropoxy (2-vinylphenyl) silane,

[0239] Dimethoxymethyl (4-vinylphenyl) silane, diethoxymethyl (4-vinylphenyl) silane, dipropoxymethyl (4-vinylphenyl) silane, dibutoxymethyl (4-vinylphenyl) silane, diisopropoxymethyl (4-vinylphenyl) silane,

[0240] Dimethoxymethyl (3-vinylphenyl) silane, diethoxymethyl (3-vinylphenyl) silane, dipropoxymethyl (3-vinylphenyl) silane, dibutoxymethyl (3-vinylphenyl) silane, diisopropoxymethyl (3-vinylphenyl) silane,

[0241] Dimethoxymethyl (2-vinylphenyl) silane, diethoxymethyl (2-vinylphenyl) silane, dipropoxymethyl (2-vinylphenyl) silane, dibutoxymethyl (2-vinylphenyl) silane, diisopropoxymethyl (2-vinylphenyl) silane,

[0242] Dimethylmethoxy(4-vinylphenyl)silane, dimethylethoxy(4-vinylphenyl)silane, dimethylpropoxy(4-vinylphenyl)silane, dimethylbutoxy(4-vinylphenyl)silane, dimethylisopropoxy(4-vinylphenyl)silane,

[0243] Dimethylmethoxy(3-vinylphenyl)silane, dimethylethoxy(3-vinylphenyl)silane, dimethylpropoxy(3-vinylphenyl)silane, dimethylbutoxy(3-vinylphenyl)silane, dimethylisopropoxy(3-vinylphenyl)silane,

[0244] Dimethylmethoxy(2-vinylphenyl)silane, dimethylethoxy(2-vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, dimethylisopropoxy(2-vinylphenyl)silane,

[0245] Trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, tripropoxy(4-isopropenylphenyl)silane, 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(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl)silane, triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, Oxy(2-isopropenylphenyl)silane, tributoxy(2-isopropenylphenyl)silane, triisopropoxy(2-isopropenylphenyl)silane, 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, dibutoxymethyl (3-isopropenylphenyl) silane, diisopropoxymethyl (3-isopropenylphenyl) silane, dimethoxymethyl (2-isopropenylphenyl) silane, diethoxymethyl (2-isopropenylphenyl) silane, dipropoxymethyl (2-isopropenylphenyl) silane, dibutoxymethyl (2-isopropenylphenyl) silane, diisopropoxymethyl (2-isopropenylphenyl) silane, dimethylmethoxy (4-isopropenylphenyl) silane, dimethylethoxy (4-isopropenylphenyl) silane, dimethylpropoxy (4-isopropenylphenyl) silane, dimethylbutoxy (4-isopropenylphenyl) silane, dimethyl Isopropoxy (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,

[0246] Trichloro(4-vinylphenyl)silane, Trichloro(3-vinylphenyl)silane,

[0247] Trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane,

[0248] 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.

[0249] Among these, preferred are 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-vinylphenyl)silane, and trichloro(4-vinylphenyl)silane; and more preferred are trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, and triisopropoxy(4-vinylphenyl)silane.

[0250] Examples of the branching agent represented by the above formula (2) include, but are not limited to:

[0251] 1,1-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,

[0252] 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-triethoxysilylphenyl)ethylene, 1,1-bis(3-tripropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(3-triisopropoxysilylphenyl)ethylene,

[0253] 1,1-bis(2-trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene, 1,1-bis(3-tripropoxysilylphenyl)ethylene, 1,1-bis(2-tripentoxysilylphenyl)ethylene, 1,1-bis(2-triisopropoxysilylphenyl)ethylene,

[0254] 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.

[0255] 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, and 1,1-bis(4-trimethoxysilylphenyl)ethylene is more preferred.

[0256] (Method for producing conjugated diene polymer)

[0257] The method for producing a conjugated diene polymer of the present embodiment is a method for producing a conjugated diene polymer having the above-mentioned Mooney viscosity, Mooney stress relaxation rate and degree of branching (Bn) within a specific range, wherein the method comprises the following steps: a polymerization and branching step, using an organic lithium compound as a polymerization initiator, polymerizing at least a conjugated diene compound while adding a branching agent to obtain a conjugated diene polymer having a main chain branch structure; and a coupling step, coupling the above-mentioned conjugated diene polymer using a coupling agent.

[0258] The method for producing the conjugated diene polymer of the present embodiment preferably comprises the following steps: a polymerization and branching step, in the presence of an organic lithium compound, using an organic lithium compound as a polymerization initiator, polymerizing at least a conjugated diene compound, and using at least any one of the above-mentioned various branching agents to obtain a conjugated diene polymer having a main chain branch structure; and a coupling step, coupling the above-mentioned conjugated diene polymer using a coupling agent or a modifier having a nitrogen atom-containing group.

[0259] The conjugated diene polymer constituting the conjugated diene polymer may be any of a homopolymer of a single conjugated diene compound, a copolymer of polymers of different types of conjugated diene compounds, and a copolymer of a conjugated diene compound and an aromatic vinyl compound.

[0260] Specific examples of the conjugated diene compound are not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the perspective of ease of industrial availability.

[0261] These compounds may be used alone or in combination of two or more.

[0262] Specific examples of the aromatic vinyl compound are not particularly limited, and examples thereof include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of ease of industrial availability.

[0263] These compounds may be used alone or in combination of two or more.

[0264] As the so-called microstructure (ratio of the amount of aromatic vinyl compound and the amount of vinyl bond) of the copolymer of conjugated diene compound and aromatic vinyl compound, the amount of aromatic vinyl compound is preferably 0-45% by mass, more preferably 0-40% by mass, and the amount of vinyl bond is preferably 23-70 mol%, more preferably 27-65 mol%. In the conjugated diene polymer of the present embodiment, the Mooney viscosity, Mooney stress relaxation rate and degree of branching are controlled by the amount of polymerization initiator added, the type (functional number) and amount of branching agent added, the type (functional number) and amount of coupling agent added, and the amount (type) of rubber softener added, and the influence of microstructure is small. Therefore, it can be appropriately designed within the range of the usual microstructure. However, as mentioned above, since the amount of aromatic vinyl compound and the amount of vinyl bond will affect the Tg of the conjugated diene polymer, it is preferably set within the above range from the aspects of fuel saving performance and braking performance.

[0265] (Polymerization and branching process)

[0266] The polymerization and branching step in the method for producing a conjugated diene polymer of the present embodiment is, for example, a step of polymerizing at least a conjugated diene compound using an organic monolithium compound as a polymerization initiator and adding a branching agent to obtain a conjugated diene polymer having a main chain branch structure.

[0267] In the polymerization step, it is preferred to polymerize by a growth reaction based on a living anionic polymerization reaction, thereby obtaining a conjugated diene polymer having an active terminal. Thereafter, in a branching step using a branching agent, the main chain branching can be appropriately controlled, and there is a tendency to obtain a conjugated diene polymer with a high modification rate.

[0268] (Polymerization initiator)

[0269] As the polymerization initiator, at least an organic monolithium compound can be used.

[0270] Examples of the organic monolithium compound include, but are not limited to, low molecular weight compounds and soluble oligomer organic monolithium compounds.

[0271] In addition, examples of the organic monolithium compound include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond in terms of the bonding form between the organic group and the lithium.

[0272] The amount of the organic monolithium compound used as a polymerization initiator is preferably determined according to the molecular weight of the desired conjugated diene polymer or modified conjugated diene polymer.

[0273] The amount of the monomer such as the conjugated diene compound used relative to the amount of the polymerization initiator used is correlated with the degree of polymerization, that is, it tends to be correlated with the number average molecular weight and / or the weight average molecular weight.

[0274] Therefore, in order to increase the molecular weight, the amount of the polymerization initiator used can be adjusted in the direction of decreasing, and in order to decrease the molecular weight, the amount of the polymerization initiator used can be adjusted in the direction of increasing.

[0275] From the viewpoint of being used in a method of introducing nitrogen atoms into a conjugated diene polymer, the organic monolithium compound is preferably an alkyllithium compound having a substituted amino group or a dialkyllithium amide.

[0276] In this case, a conjugated diene polymer having a nitrogen atom derived from an amino group at the polymerization initiation terminal is obtained.

[0277] The substituted amino group is an amino group having no active hydrogen or a structure in which the active hydrogen is protected.

[0278] Examples of the alkyl lithium compound having an amino group without active hydrogen include, but are not limited to, 3-dimethylaminopropyl lithium, 3-diethylaminopropyl lithium, 4-(methylpropylamino)butyl lithium and 4-hexamethyleneiminobutyl lithium.

[0279] Examples of the alkyl lithium compound having an amino group with active hydrogen protected include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0280] Examples of the dialkyl lithium amide include, but are not limited to, dimethyl lithium amide, diethyl lithium amide, dipropyl lithium amide, dibutyl lithium amide, di-n-hexyl lithium amide, diheptyl lithium amide, diisopropyl lithium amide, dioctyl lithium amide, di-2-ethylhexyl lithium amide, didecyl lithium amide, ethylpropyl lithium amide, ethylbutyl lithium amide, ethylbenzyl lithium amide, methylphenethyl lithium amide, hexamethylene imide, lithium pyrrolidine, lithium piperidine, lithium heptamethylene imide, lithium morpholine, 1-lithium azacyclooctane, 6-lithium-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane and 1-lithium-1,2,3,6-tetrahydropyridine.

[0281] These organic monolithium compounds having a substituted amino group can also be used as organic monolithium compounds of solubilized oligomers by reacting a small amount of a polymerizable monomer such as 1,3-butadiene, isoprene, or styrene.

[0282] As the organic monolithium compound, an alkyl lithium compound is preferred from the viewpoint of ease of industrial availability and ease of control of the polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal can be obtained.

[0283] 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.

[0284] As the alkyl lithium compound, n-butyl lithium and sec-butyl lithium are preferred from the viewpoint of ease of industrial availability and ease of control of the polymerization reaction.

[0285] These organic monolithium compounds may be used alone or in combination of two or more, or may be used in combination with other organic metal compounds.

[0286] Examples of the other organic metal compounds include alkaline earth metal compounds, other alkali metal compounds, and other organic metal compounds.

[0287] Examples of the alkaline earth metal compound include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds, and examples also include alkoxides, sulfonates, carbonates, and amide compounds of alkaline earth metals.

[0288] Examples of the organomagnesium compound include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

[0289] In the polymerization step, examples of the polymerization reaction mode include, but are not limited to, a batch-type (also referred to as a "batch-type") and a continuous-type polymerization reaction mode.

[0290] In the continuous method, one or more connected reactors can be used. The continuous reactor, for example, uses a tank-type or tube-type reactor with a stirrer. In the continuous method, preferably, monomers, an inert solvent, and a polymerization initiator are continuously loaded into the reactor, a polymer solution containing a polymer is obtained in the reactor, and the polymer solution is continuously discharged.

[0291] The batch reactor is, for example, a tank reactor with a stirrer. In the batch reactor, preferably, monomers, an inert solvent and a polymerization initiator are loaded, and monomers are added continuously or intermittently during the polymerization as required to obtain a polymer solution containing a polymer in the reactor, and the polymer solution is discharged after the polymerization is completed.

[0292] In the method for producing a conjugated diene polymer of the present embodiment, in order to obtain a conjugated diene polymer having active terminals at a high ratio, a continuous method is preferred in which the polymer can be continuously discharged and supplied to the next reaction in a short time.

[0293] The polymerization process of the conjugated diene polymer is preferably carried out in an inert solvent. The solvent is not particularly limited, and examples thereof include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents 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 composed of mixtures thereof.

[0294] By treating allenes and acetylenes as impurities with an organic metal compound before subjecting them to the polymerization reaction, a conjugated diene polymer having a high concentration of active terminals tends to be obtained, and a conjugated diene polymer having a high modification rate tends to be obtained, which is preferred.

[0295] Polar compounds can be added in the polymerization process. There is a tendency that the aromatic vinyl compound and the conjugated diene compound can be randomly copolymerized and can also be used as a vinylating agent for controlling the microstructure of the conjugated diene part. There is also a tendency that the effect is also exerted in the promotion of the polymerization reaction.

[0296] As polar compounds, there can be mentioned, 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, 2,2-bis(2-tetrahydrofuranyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidylethane, trimethylamine, triethylamine, pyridine, quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butoxide, sodium tert-butoxide, sodium amylate; phosphine compounds such as triphenylphosphine, etc.

[0297] These polar compounds may be used alone or in combination of two or more.

[0298] The amount of the polar compound used is not particularly limited and may be selected depending on the purpose etc., but is preferably 0.01 mol or more and 100 mol or less per 1 mol of the polymerization initiator.

[0299] Such polar compounds (vinylating agents) can be used in appropriate amounts as regulators of the microstructure of the conjugated diene portion of the polymer according to the desired vinyl bond amount. Most polar compounds have an effective randomizing effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to be used as distribution regulators of aromatic vinyl compounds or regulators of styrene block amount.

[0300] As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, the following method can be used, as described in Japanese Patent Application Laid-Open No. 59-140211: a copolymerization reaction is initiated using the total amount of styrene and a part of 1,3-butadiene, and the remaining 1,3-butadiene is intermittently added during the copolymerization reaction.

[0301] The polymerization temperature in the polymerization step is preferably a temperature for performing living anionic polymerization, and is more preferably 0°C or higher and 120°C or lower from the perspective of productivity. By setting the temperature in such a range, there is a tendency to ensure a sufficient amount of the modifier reacted with respect to the active terminal after the polymerization is completed. More preferably, it is 50°C or higher and 100°C or lower.

[0302] In the method for producing a conjugated diene polymer of the present embodiment, the amount of the branching agent added in the branching step of forming a main chain branch structure is not particularly limited and can be selected according to the purpose, etc., and is preferably 0.03 mol to 0.5 mol, more preferably 0.05 mol to 0.4 mol, and further preferably 0.01 mol to 0.25 mol relative to 1 mol of the polymerization initiator.

[0303] The branching agent can be used in an appropriate amount according to the desired number of branching points of the main chain branch structure of the conjugated diene part of the conjugated diene polymer.

[0304] In the branching step, the timing of adding the branching agent is not particularly limited and can be selected according to the purpose, etc. From the perspective of increasing the absolute molecular weight of the modified conjugated diene polymer and increasing the modification rate, it is preferably added at a time when the raw material conversion rate is 20% or more after the polymerization initiator is added. The conversion rate is more preferably 40% or more, further preferably 50% or more, further more preferably 65% ​​or more, and further more preferably 75% or more.

[0305] Furthermore, after adding the branching agent, a desired raw material may be further added, and the polymerization step may be continued after branching, or the above-described contents may be repeated.

[0306] The additional monomer is not particularly limited. From the perspective of increasing the modification rate of the conjugated diene polymer, it is preferably 5% or more of the total amount of the conjugated diene monomer used in the polymerization step (for example, the total amount of butadiene), more preferably 10% or more, further preferably 15% or more, still more preferably 20% or more, and still more preferably 25% or more and 30% or less.

[0307] When the amount of the additional monomer is within the above range, the molecular weight between the branching point based on the branching agent and the branching point based on the coupling agent becomes longer, and there is a tendency to easily obtain a molecular structure with high linearity. By forming a molecular structure with high linearity, the entanglement of molecular chains of the conjugated diene polymer increases after the vulcanization, and there is a tendency to obtain a rubber composition with excellent wear resistance, handling stability and breaking strength.

[0308] The conjugated diene polymer of the present embodiment is not particularly limited, and can be a polymer of a conjugated diene monomer and a branching agent, or a copolymer of a conjugated diene monomer, a branching agent and monomers other than these. For example, when the conjugated diene monomer is butadiene or isoprene and is polymerized with a branching agent containing a vinyl aromatic part, the polymer chain is so-called polybutadiene or polyisoprene, and the branched part contains a polymer having a structure from vinyl aromatics. By having such a structure, the linearity of each chain of the polymer chain can be improved, and the crosslinking density after vulcanization can be improved, etc., and the effect of improving wear resistance is exerted. Therefore, the conjugated diene polymer of the present embodiment is suitable for tires, resin modification, interior and exterior decoration products of automobiles, shockproof rubber, footwear and other purposes.

[0309] When the conjugated diene polymer is used for tire tread, a copolymer of a conjugated diene monomer, an aromatic vinyl monomer and a branching agent is suitable. In the copolymer for this purpose, the amount of bonded conjugated diene is preferably from 40% by mass to 100% by mass, and more preferably from 55% by mass to 80% by mass.

[0310] The amount of bonded aromatic vinyl groups in the conjugated diene polymer of the present embodiment is not particularly limited, but is preferably 0% by mass to 60% by mass, and more preferably 20% by mass to 45% by mass.

[0311] When the amount of the bonded conjugated diene and the amount of the bonded aromatic vinyl are within the above ranges, the sulfide tends to have a better balance between low hysteresis loss and wet skid resistance, and also has better wear resistance and breaking strength.

[0312] Here, the amount of bonded aromatic vinyl groups can be measured by ultraviolet absorption of phenyl groups, and the amount of bonded conjugated dienes can also be determined from this. Specifically, the amount is measured according to the method described in the examples below.

[0313] In the conjugated diene polymer of the present embodiment, the vinyl bond content in the conjugated diene bond unit is not particularly limited, but is preferably 10 mol% to 75 mol%, and more preferably 20 mol% to 65 mol%.

[0314] When the vinyl bond content is within the above range, the balance between low hysteresis loss and wet skid resistance after being made into a sulfide, as well as the wear resistance and breaking strength tend to be more excellent. Here, when the modified diene polymer is a copolymer of butadiene and styrene, the vinyl bond content (1,2-bond content) in the butadiene bond unit can be obtained by the Hampton method (RR Hampton, Analytical Chemistry, 21, 923 (1949)). Specifically, it is measured by the method described in the examples described below.

[0315] Regarding the microstructure of the conjugated diene polymer of the present embodiment, when the amount of each bond in the conjugated diene polymer is within the above range and the glass transition temperature of the conjugated diene polymer is within the range of -70°C to -15°C, there is a tendency to obtain a sulfide with a further excellent balance between low hysteresis loss and wet skid resistance. Regarding the glass transition temperature, according to ISO 22768:2006, a DSC curve is recorded while heating in a prescribed temperature range, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature. Specifically, it is measured by the method described in the examples described later.

[0316] In the case where the conjugated diene polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferred that the number of blocks formed by linking more than 30 aromatic vinyl units is small or non-existent. More specifically, in the case where the copolymer is a butadiene-styrene copolymer, in a known method for decomposing the copolymer and analyzing the amount of polystyrene insoluble in methanol using the method of Kolthoff (IM KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)), the block formed by linking more than 30 aromatic vinyl units is preferably less than 5.0% by mass, more preferably less than 3.0% by mass relative to the total amount of the copolymer.

[0317] When the conjugated diene polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferred that the proportion of the aromatic vinyl unit alone is high from the viewpoint of improving fuel efficiency.

[0318] Specifically, when the copolymer is a butadiene-styrene copolymer, when the copolymer is decomposed by a method based on ozone decomposition known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)) and the styrene linkage distribution is analyzed by GPC, it is preferred that the separated styrene amount is 40% by mass or more and the linked styrene structure with 8 or more styrene chains is 5.0% by mass or less relative to the total bonded styrene amount.

[0319] In this case, the obtained vulcanized rubber has excellent properties such as particularly low hysteresis loss.

[0320] (Coupling process)

[0321] The method for producing the conjugated diene polymer of the present embodiment preferably comprises a coupling step of coupling the conjugated diene polymer obtained in the above-mentioned polymerization and branching steps using a coupling agent. As the coupling step, for example, it is preferred to use a trifunctional or higher reactive compound (hereinafter also referred to as a "coupling agent") or a coupling agent having a nitrogen atom-containing group for the active end of the conjugated diene polymer.

[0322] In the coupling step, for example, a coupling reaction may be performed on one active terminal of the conjugated diene polymer using a coupling agent or a modifier having a nitrogen atom-containing group to obtain the conjugated diene polymer.

[0323] (Coupling agent)

[0324] In the method for producing a conjugated diene polymer according to the present embodiment, the coupling agent used in the coupling step may have any structure as long as it is a trifunctional or higher-functional reactive compound, and is preferably a trifunctional or higher-functional reactive compound having a silicon atom.

[0325] Examples of the trifunctional or higher-functional reactive compound having a silicon atom include, but are not limited to, halogenated silane compounds, epoxidized silane compounds, vinylated silane compounds, alkoxysilane compounds, and alkoxysilane compounds containing a nitrogen-containing group.

[0326] Examples of the halogenated silane compound that is a coupling agent 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.

[0327] Examples of the epoxidized silane compound as a coupling agent include, but are not limited to, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and epoxy-modified silicone.

[0328] Examples of the alkoxysilane compound as a coupling agent include, but are not limited to, tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, 1,2-bis(triethoxysilyl)ethane, and methoxy-substituted polyorganosiloxane.

[0329] (Modifier having a nitrogen atom-containing group)

[0330] Examples of the modifier having a nitrogen atom group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing nitrogen atom groups, vinyl compounds containing nitrogen atom groups, and epoxy compounds containing nitrogen atom groups.

[0331] Among the modifiers having a nitrogen atom-containing group, the nitrogen atom-containing functional group is preferably an amine compound having no active hydrogen, for example, a tertiary amine compound, a protected amine compound in which the above active hydrogen is substituted by a protecting group, an imine compound represented by the general formula -N=C, and an alkoxysilane compound bonded to the above nitrogen atom-containing group.

[0332] Examples of isocyanate compounds that are modifiers having a nitrogen atom-containing group include, but are not limited to, 2,4-benzylene diisocyanate, 2,6-benzylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, and 1,3,5-benzene triisocyanate.

[0333] Examples of isocyanuric acid derivatives that are modifiers 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-tris(oxiran-2-yl)-1,3,5-triazine-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5-triazine-2,4,6-trione, and 1,3,5-trivinyl-1,3,5-triazine-2,4,6-trione.

[0334] Examples of carbonyl compounds that are modifiers 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, Ketone, 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-diethylcarbamic acid methyl ester, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylpicolinamide, N,N-dimethylisonicotinamide, etc.

[0335] Examples of vinyl compounds that are modifiers 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.

[0336] Examples of epoxy compounds that are modifiers having a nitrogen atom-containing group include, but are not limited to, hydrocarbon compounds containing an epoxy group bonded to an amino group, which may further have an epoxy group bonded to an ether group. Examples of such epoxy compounds include, but are not limited to, epoxy compounds represented by general formula (i).

[0337] [Chemistry 7]

[0338]

[0339] In the above formula (i), R is a hydrocarbon group with a valence of 2 or more, or a divalent organic group with a valence of 2 or more having at least one polar group selected from polar groups having oxygen such as ether, epoxy, ketone, polar groups having sulfur such as thioether, thioketone, and polar groups having nitrogen such as tertiary amino, imino, etc.

[0340] The hydrocarbon group with a valency of more than 2 is saturated or unsaturated and may be a straight chain, branched chain or cyclic hydrocarbon group, including alkylene, alkenylene, phenylene, etc. A hydrocarbon group with a carbon number of 1 to 20 is preferred. For example, methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-phenylene, m-phenylene, p-phenylene, m-xylene, p-xylene, bis(phenylene)-methane, etc. can be cited.

[0341] In the above formula (i), R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 They can be the same as or different from each other.

[0342] In the above formula (i), R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 They can be the same as or different from each other.

[0343] In the above formula (i), R 3 It is a hydrocarbon group having 1 to 10 carbon atoms, or a structure represented by the following formula (ii).

[0344] R 1 , R 2 , R 3 It may be a ring structure formed by mutual bonding.

[0345] In addition, R 3 In the case of a hydrocarbon group, it may be a cyclic structure formed by bonding with R. In the case of the above cyclic structure, it may be a cyclic structure formed by bonding with R 3 The bonded N and R are directly bonded.

[0346] In the above formula (i), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

[0347] [Chemistry 8]

[0348]

[0349] In the above formula (ii), R 1 , R 2 R of the above formula (i) 1 , R2 Similarly, R 1 , R 2 They can be the same as or different from each other.

[0350] As the epoxy compound which is a modifier having a nitrogen atom-containing group, an epoxy compound having a hydrocarbon group containing an epoxy group is preferred, and an epoxy compound having a hydrocarbon group containing a glycidyl group is more preferred.

[0351] The hydrocarbon group containing an epoxy group bonded to an amino group or an ether group is not particularly limited, and examples thereof include a glycidylamino group, a diglycidylamino group, or a glycidyloxy group. A further preferred molecular structure is an epoxy group-containing compound having a glycidylamino group or a diglycidylamino group, and a glycidyloxy group, and examples thereof include compounds represented by the following general formula (iii).

[0352] [Chemistry 9]

[0353]

[0354] In the above formula (iii), R is defined in the same manner as R in the above formula (i), and R 6 It is a hydrocarbon group having 1 to 10 carbon atoms or a structure represented by the following formula (iv).

[0355] R 6 When it is a hydrocarbon group, it can be bonded with R to form a ring structure. In this case, it can be 6 The bonded N and R are directly bonded.

[0356] In the formula (iii), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

[0357] [Chemistry 10]

[0358]

[0359] As the epoxy compound which is a modifier having a nitrogen atom-containing group, a compound having one or more diglycidylamino groups and one or more glycidyloxy groups in the molecule is particularly preferred.

[0360] Examples of epoxy compounds used as modifiers having a nitrogen atom-containing group include, but are not limited to, N,N-diglycidyl-4-glycidyloxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidyloxy-cyclohexane, 4-(4-glycidyloxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidyloxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidyloxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidyloxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl 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-diglycidyl o-toluidine, N,N-diglycidylaminomethylcyclohexane, and the like. Among these, particularly preferred compounds include N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0361] Examples of the alkoxysilane compound that is a modifier having a nitrogen atom-containing group include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinylpropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazinyl)propyltriethoxysilane, 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperazinyl)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltriethoxysilane, Propyltrimethoxysilane, 3-dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, bis(3-dimethoxymethylsilylpropyl)-N-methylamine, bis(3-trimethoxysilylpropyl)-N-methylamine, bis(3-triethoxysilylpropyl)methylamine, tris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N',N'-tetrakis(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,

[0362] 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 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, 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silacyclooctane, etc.

[0363] Regarding the protected amine compound that can form a primary amine or secondary amine in the modifier having a nitrogen atom-containing group, examples of compounds having an unsaturated bond and a protected amine in the molecule include, but are not limited to, 4,4'-vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(tert-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(tert-butyldimethylsilyl)aniline], Vinylbis[N-methyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(tert-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(tert-butyldimethylsilyl)aniline], 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N-methyl-N-(trimethylsilyl)aminophenyl]ethylene, 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethylaminophenyl]ethylene, and the like.

[0364] As for the protected amine compound that can form a primary or secondary amine in the modifier having a nitrogen atom-containing group, examples of compounds having 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, N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazinyl)propyltriethoxysilane, 3-(3-triethylsilyl)aminopropylmethyldiethoxysilane, and the like. -1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 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-trimethoxy 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, and the like.

[0365] Particularly preferred alkoxysilane compounds that are modifiers 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-propylenediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-silacyclopentane)propyl]-1,3-propylenediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, 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, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, 1,6-hexanediamine, penta(3-trimethoxysilylpropyl)-diethylenetriamine, tri(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, 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)-cyclohexyl-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane2-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.

[0366] (Preferred Structure of Conjugated Diene Polymer)

[0367] The conjugated diene polymer of the present embodiment preferably includes a structure derived from a compound having a nitrogen atom-containing group represented by the following general formula (i) or any one of (A) to (C).

[0368] [Chemistry 11]

[0369]

[0370] In the above formula (i), R is a hydrocarbon group with a valence of 2 or more, or a divalent organic group with a valence of 2 or more having at least one polar group selected from polar groups having oxygen such as ether, epoxy, ketone, polar groups having sulfur such as thioether, thioketone, and polar groups having nitrogen such as tertiary amino, imino, etc.

[0371] The hydrocarbon group with a valency of more than 2 is saturated or unsaturated and may be a straight chain, branched chain or cyclic hydrocarbon group, including alkylene, alkenylene, phenylene, etc. A hydrocarbon group with a carbon number of 1 to 20 is preferred. For example, methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-phenylene, m-phenylene, p-phenylene, m-xylene, p-xylene, bis(phenylene)-methane, etc. can be cited.

[0372] In the above formula (i), R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 They can be the same as or different from each other.

[0373] In the above formula (i), R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 They can be the same as or different from each other.

[0374] In the above formula (i), R 3 It is a hydrocarbon group having 1 to 10 carbon atoms, or a structure represented by the following formula (ii).

[0375] R 1 , R 2 , R 3 It may be a ring structure formed by mutual bonding.

[0376] In addition, R 3 In the case of a hydrocarbon group, it may be a cyclic structure formed by bonding with R. In the case of the above cyclic structure, it may be a cyclic structure formed by bonding with R 3 The bonded N and R are directly bonded.

[0377] In the above formula (i), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

[0378] [Chemistry 12]

[0379]

[0380] In the above formula (ii), R 1 , R 2 R of the above formula (i) 1 , R 2 Similarly, R 1 , R 2 They can be the same as or different from each other.

[0381] [Chemistry 13]

[0382]

[0383] (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, and R 5 represents an alkylene group having 1 to 10 carbon atoms, R 6 It represents an alkylene group having 1 to 20 carbon atoms.

[0384] 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 Each is independent.)

[0385] [Chemistry 14]

[0386]

[0387] (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, and R 7 ~R 9 Each independently represents an alkylene group having 1 to 20 carbon atoms.

[0388] m, n and l each independently represent an integer of 1 to 3, and (m+n+l) represents an integer of 4 or greater. 1 ~R 6 Each is independent.)

[0389] [Chemistry 15]

[0390]

[0391] (In formula (C), R 12 ~R 14 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, and 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, and R 21 It represents an alkyl group having 1 to 20 carbon atoms or a trialkylsilyl group.

[0392] m represents an integer of 1 to 3, and p represents 1 or 2.

[0393] When there are multiple R 12 ~R 22 , m and p are independent of each other and may be the same or different.

[0394] 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.

[0395] 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.

[0396] Examples of the modifier having a nitrogen atom-containing group represented by the formula (A) include, but are not limited to, 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-silacycloheptane, and 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane. aza-2-silacyclopentane, 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.

[0397] Among these, from the viewpoint of reactivity and interaction between the functional group of the modifier having a nitrogen atom-containing group and an inorganic filler such as silicon oxide, and from the viewpoint of processability, it is preferred that m represents 2 and n represents 3. Specifically, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane and 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane are preferred.

[0398] The reaction temperature and reaction time when reacting the modifier having a nitrogen atom-containing group represented by the formula (A) with the polymerization active terminal are not particularly limited, but the reaction is preferably carried out at 0° C. to 120° C. for 30 seconds or more.

[0399] The total molar number of alkoxy groups bonded to the silyl group in the compound of the modifier having a nitrogen atom-containing group represented by the above formula (A) is preferably in the range of 0.6 to 3.0 times the added molar number of the alkali metal compound and / or alkaline earth metal compound of the polymerization initiator, more preferably in the range of 0.8 to 2.5 times, and further preferably in the range of 0.8 to 2.0 times. From the perspective of obtaining a sufficient modification rate, molecular weight, and branched structure of the obtained conjugated diene polymer, it is preferably 0.6 times or more, and from the perspective of preferably coupling the polymer ends to each other to obtain a branched polymer component in order to improve processability, and from the perspective of the cost of the modifier, it is preferably 3.0 times or less.

[0400] More specifically, the molar number of the polymerization initiator is preferably 3.0 times or more, more preferably 4.0 times or more, based on the molar number of the modifier.

[0401] Examples of the modifier having a nitrogen atom-containing group represented by the above 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.

[0402] Among these, from the aspects of reactivity and interaction between the functional group of the modifier and the inorganic filler such as silica and processability, it is preferred that n, m and l all represent 3. Preferred specific examples include tris(3-trimethoxysilylpropyl)amine and tris(3-triethoxysilylpropyl)amine.

[0403] The reaction temperature and reaction time when reacting the modifier having a nitrogen atom-containing group represented by the formula (B) with the polymerization active terminal are not particularly limited, but the reaction is preferably carried out at 0° C. to 120° C. for 30 seconds or more.

[0404] The total molar number of the alkoxy groups bonded to the silyl group in the compound of the modifier represented by formula (B) is preferably in the range of 0.6 to 3.0 times the molar number of the lithium constituting the above-mentioned polymerization initiator, more preferably in the range of 0.8 to 2.5 times, and further preferably in the range of 0.8 to 2.0 times. From the perspective of obtaining a sufficient modification rate, molecular weight, and branched structure in the conjugated diene polymer, it is preferably 0.6 times or more, and from the perspective of preferably coupling the polymer ends to each other to obtain a branched polymer component in order to improve processability, and from the perspective of the cost of the modifier, it is preferably 3.0 times or less.

[0405] More specifically, the molar number of the polymerization initiator is preferably 4.0 times or more, more preferably 5.0 times or more, based on the molar number of the modifier.

[0406] In the above formula (C), A is preferably represented by any one of the following general formulae (II) to (V).

[0407] [Chemistry 16]

[0408]

[0409] (In formula (II), B 1represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When there are plural B 1 Each is independent.)

[0410] [Chemistry 17]

[0411]

[0412] (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. When there are plural numbers of B 2 and B 3 Each is independent.)

[0413] [Chemistry 18]

[0414]

[0415] (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. When there are plural B 4 Each is independent.)

[0416] [Chemistry 19]

[0417]

[0418] (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. When there are plural B 5 Each is independent.)

[0419] In the above formula (C), as the modifier having a nitrogen atom-containing group when A is represented by formula (II), for example, but 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, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine 1,3-propylenediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine 1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silanyl-2-azacyclopentane)propyl]-1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silanyl-2-azacyclopentane)propyl]-1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silanyl-2-azacyclopentane)propyl]-1,3-propylenediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silanyl)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-silanyl-2-azacyclopentane)propyl]-1,3-propylenediamine 1,3-propylenediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propylenediamine, tetrakis(3-triethoxysilylpropyl)-1,3-propylenediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propylenediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propylenediamine, 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, 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, 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- Bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, 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-propylenediamine, Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy- 2-Trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-[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, 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-propylenediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-bis(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane [3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propylenediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1- 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, 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-hexanediamine and penta(3-trimethoxysilylpropyl)-diethylenetriamine.

[0420] In the above formula (C), when A is represented by the formula (III), the modifier having a nitrogen atom-containing group may include, but is not limited to, tris(3-trimethoxysilylpropyl)-methyl-1,3-propylenediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propylenediamine, 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, N 1 ,N 1 '-(Propane-1,3-diyl)bis(N 1 -Methyl-N 3 ,N 3 -bis(3-(trimethoxysilyl)propyl)-1,3-propylenediamine) 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.

[0421] In the above formula (C), when A is represented by the formula (IV), the modifier having a nitrogen atom-containing group may be, for example, but 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-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-sila-2-cyclopentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-sila-2-cyclopentane)propyl]silane cyclopentane)propyl] 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)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] silane 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.

[0422] In the above formula (C), as the modifier having a nitrogen atom-containing group when A is represented by formula (V), for example, but 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 can be mentioned.

[0423] In the above formula (C), A is preferably represented by formula (II) or formula (III), and k represents 0.

[0424] Such a modifier having a nitrogen atom-containing group tends to be easily available, and also tends to have better wear resistance and low hysteresis loss performance after the conjugated diene polymer is made into a sulfide. Examples of such a modifier having 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-propylenediamine, tetrakis[3-(2, [3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-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-trimethoxysilylpropyl)-methyl-1,3-propanediamine.

[0425] In the above 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.

[0426] As a result, the wear resistance and low hysteresis loss performance after conversion into a sulfide tend to be more excellent.

[0427] Examples of such a modifier having a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propylenediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine, 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.

[0428] Regarding the added amount of the compound represented by the above formula (C) as a modifier having a nitrogen atom-containing group, the number of moles of the conjugated diene polymer can be adjusted relative to the number of moles of the modifier so that the reaction is carried out in a desired stoichiometric ratio, thereby tending to achieve the desired star-shaped high-branching structure.

[0429] Specifically, the number of moles of the polymerization initiator is preferably 5.0 times or more, more preferably 6.0 times or more, based on the number of moles of the modifier.

[0430] In this case, in the formula (C), the number of functional groups of the modifier ((m-1)×i+p×j+k) is preferably an integer of 5-10, and more preferably an integer of 6-10.

[0431] In the conjugated diene polymer of the present embodiment, the ratio of the nitrogen atom-containing polymer in the conjugated diene polymer is represented by a modification ratio.

[0432] The modification rate is preferably 60% by mass or more, more preferably 65% ​​by mass or more, further preferably 70% by mass or more, further preferably 75% by mass or more, still more preferably 80% by mass or more, particularly preferably 82% by mass or more.

[0433] When the modification ratio is 60 mass % or more, the processability when producing the sulfide is excellent, and the wear resistance and low hysteresis loss performance after producing the sulfide tend to be more excellent.

[0434] In the present embodiment, a condensation reaction step of performing a condensation reaction in the presence of a condensation accelerator may be performed after the coupling step or before the coupling step.

[0435] In the conjugated diene polymer of the present embodiment, the conjugated diene part may be hydrogenated.

[0436] The method for hydrogenating the conjugated diene part of the conjugated diene polymer is not particularly limited, and a known method can be used.

[0437] As a suitable hydrogenation method, a method of hydrogenation using a method of blowing gaseous hydrogen into a polymer solution in the presence of a catalyst can be cited. The catalyst is not particularly limited, and for example, heterogeneous catalysts such as catalysts in which noble metals are loaded on porous inorganic substances; catalysts in which salts of nickel, cobalt, etc. are made solubilized and reacted with organic aluminum, etc.; homogeneous catalysts such as catalysts of metallocenes such as cyclopentadiene titanium are used. Among these, cyclopentadiene titanium catalysts are preferred from the aspect of being able to select mild hydrogenation conditions. In addition, the hydrogenation of aromatic groups can be carried out by using a catalyst loaded with noble metals.

[0438] Examples of hydrogenation catalysts include, but are not limited to: (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silicon oxide, aluminum oxide, diatomaceous earth, and the like; (2) so-called Ziegler-type hydrogenation catalysts using organic acid salts or transition metal salts such as acetylacetonate of Ni, Co, Fe, and Cr and reducing agents such as organic aluminum; (3) so-called organic metal complexes such as organic metal compounds of Ti, Ru, Rh, and Zr; and the like. Furthermore, the hydrogenation catalyst is not particularly limited, and examples thereof include known hydrogenation catalysts described in, for example, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-37970, Japanese Patent Publication No. 1-53851, Japanese Patent Publication No. 2-9041, and Japanese Patent Publication No. 8-109219. Preferred hydrogenation catalysts include reaction mixtures of cyclopentadienyl titanium compounds and reducing organometallic compounds.

[0439] In the method for producing a conjugated diene polymer according to the present embodiment, a deactivating agent, a neutralizing agent, and the like may be added to the polymer solution after the coupling step as necessary.

[0440] Examples of the deactivating agent include, but are not limited to, water; alcohols such as methanol, ethanol, and isopropanol; and the like.

[0441] Examples of the neutralizing agent include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and neodecanoic acid (a mixture of multi-branched carboxylic acids having 9 to 11 carbon atoms, with 10 being the main carbon atoms); aqueous solutions of inorganic acids; and carbon dioxide.

[0442] In the method for producing the conjugated diene polymer of the present embodiment, it is preferred to add a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing.

[0443] As the rubber stabilizer, the following known rubber stabilizers may be used but are not limited thereto, 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.

[0444] In order to further improve the productivity of the conjugated diene polymer of the present embodiment and the processability after it is made into a composition mixed with a filler and the like, a rubber softener may be added as needed.

[0445] The rubber softener is not particularly limited, and examples thereof include extender oil, liquid rubber, and resin.

[0446] As a method for adding a rubber softener to a conjugated diene polymer, a method is preferred but not limited to the following: adding a rubber softener to a conjugated diene polymer solution, mixing to prepare a polymer solution containing a rubber softener, and desolvating the solution.

[0447] Preferred extender oils include, for example, aromatic oils, cycloparaffin oils, paraffin oils, and the like. Among these, from the perspective of environmental safety, prevention of oil seepage, and wet grip properties, alternative aromatic oils having a polycyclic aromatic (PCA) content of 3% by mass or less based on the IP346 method are preferred. Alternative aromatic oils include TDAE (Treated Distillate Aromatic Extracts) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts).

[0448] Preferred liquid rubbers include, but are not limited to, liquid polybutadiene, liquid styrene-butadiene rubber, and the like.

[0449] As an effect of adding liquid rubber, the processability of the composition prepared by mixing the conjugated diene polymer and the filler can be improved, and the glass transition temperature of the composition can be shifted to the low temperature side, thereby tending to improve the wear resistance, low hysteresis loss and low temperature characteristics of the vulcanized product.

[0450] As preferred resins, there can be cited, but not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, derivatives of tall oil, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, oligomers of monoolefins, oligomers of dienes, aromatic hydrocarbon resins, aromatic petroleum resins, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, esters of hydrogenated oil resins and monofunctional or polyfunctional alcohols, etc. These resins can be used alone or in combination of two or more. In the case of hydrogenation, all unsaturated groups can be hydrogenated, or a portion can remain.

[0451] The effects of adding the resin include improved processability after mixing the conjugated diene polymer and the filler to form a composition, improved breaking strength after forming a vulcanizate, and improved wet skid resistance by shifting the glass transition temperature of the composition to a higher temperature.

[0452] The amount of the extender oil, liquid rubber or resin added as a rubber softener is not particularly limited, but is preferably 1 part by mass to 60 parts by mass, more preferably 5 parts by mass to 50 parts by mass, and further preferably 10 parts by mass to 37.5 parts by mass, relative to 100 parts by mass of the modified conjugated diene polymer of the present embodiment.

[0453] When the rubber softener is added within the above range, the processability of the composition after mixing the conjugated diene polymer and the filler etc. is good, and the breaking strength and abrasion resistance of the vulcanized product tend to be good.

[0454] (Desolventization process)

[0455] In the method for producing the conjugated diene polymer of the present embodiment, a known method can be used as a method for obtaining the obtained conjugated diene polymer from the polymer solution. The method is not particularly limited, and examples thereof include: a method of obtaining the polymer by filtering out the polymer after separating the solvent by steam stripping, and further dehydrating and drying the polymer; a method of concentrating the polymer by a flash tank, and further devolatilizing the polymer by a venting extruder, etc.; a method of directly devolatilizing the polymer by a rotary dryer, etc.

[0456] (Rubber composition)

[0457] The rubber composition of the present embodiment includes a rubber component and 5.0 parts by mass or more and 150 parts by mass or less of a filler relative to 100 parts by mass of the rubber component.

[0458] Furthermore, the rubber component contains 10 parts by mass or more of the conjugated diene polymer or the conjugated diene polymer composition relative to the total amount (100 parts by mass) of the rubber component in order to improve fuel efficiency, processability and wear resistance.

[0459] In addition, the filler preferably contains a silicon oxide-based inorganic filler.

[0460] The rubber composition of the present embodiment has a silica-based inorganic filler dispersed therein, so that the processability when preparing a vulcanizate tends to be more excellent, and the wear resistance, breaking strength, and balance between low hysteresis loss and wet skid resistance after preparing a vulcanizate tend to be more excellent.

[0461] When the rubber composition of the present embodiment is used for tires, automobile parts such as anti-vibration rubber, and vulcanized rubber applications such as shoes, it is also preferable to contain a silica-based inorganic filler.

[0462] In the rubber composition of the present embodiment, a rubbery polymer other than the above-mentioned conjugated diene polymer (hereinafter simply referred to as “rubbery polymer”) may be used in combination with the above-mentioned conjugated diene polymer.

[0463] Examples of such rubbery 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, non-diene polymers, and natural rubber.

[0464] Specific rubber-like polymers include, but are not limited to, styrene-based elastomers such as butadiene rubber or its hydrogenates, isoprene rubber or its hydrogenates, styrene-butadiene rubber or its hydrogenates, styrene-butadiene block copolymers or their hydrogenates, styrene-isoprene block copolymers or their hydrogenates, and nitrile rubber or its hydrogenates.

[0465] 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.

[0466] Examples of natural rubber include, but are not limited to, RSS No. 3 to No. 5 smoked sheet rubber, SMR, and epoxidized natural rubber.

[0467] The above-mentioned various rubber-like polymers may be modified rubbers to which polar functional groups such as hydroxyl groups and amino groups are added. When used for tire applications, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber and butyl rubber are preferably used.

[0468] From the aspect of the balance between performance and processing characteristics, the weight average molecular weight of the rubbery polymer is preferably 2000 to 2000000, more preferably 5000 to 1500000. In addition, low molecular weight rubbery polymers, i.e., so-called liquid rubbers, can also be used. These rubbery polymers can be used alone or in combination of two or more.

[0469] When the rubber composition of the present embodiment is made into a rubber composition containing the above-mentioned conjugated diene polymer and a rubber-like polymer, the content ratio (mass ratio) of the above-mentioned conjugated diene polymer to the rubber-like polymer is preferably 10 / 90 to 100 / 0, more preferably 20 / 80 to 90 / 10, and further preferably 50 / 50 to 80 / 20.

[0470] Therefore, in the rubber component, the conjugated diene polymer preferably contains 10 parts by mass to 100 parts by mass, more preferably 20 parts by mass to 90 parts by mass, and even more preferably 50 parts by mass to 80 parts by mass, relative to the total amount (100 parts by mass) of the rubber component.

[0471] When the content ratio of (the above-mentioned conjugated diene polymer / rubber-like polymer) is within the above-mentioned range, the vulcanized product has excellent wear resistance and breaking strength, and a good balance between low hysteresis loss and wet skid resistance.

[0472] Examples of fillers included in the rubber composition of the present embodiment include, but are not limited to, silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred.

[0473] The filler may be used alone or in combination of two or more.

[0474] The content of the filler in the rubber composition of the present embodiment is 5.0 parts by mass to 150 parts by mass, preferably 20 parts by mass to 100 parts by mass, and more preferably 30 parts by mass to 90 parts by mass, relative to 100 parts by mass of the rubber component containing the conjugated diene polymer.

[0475] In the rubber composition of the present embodiment, the content of the filler is 5.0 parts by mass or more relative to 100 parts by mass of the rubber component from the perspective of expressing the effect of adding the filler, and is 150 parts by mass or less relative to 100 parts by mass of the rubber component from the perspective of sufficiently dispersing the filler and making the processability and mechanical strength of the composition sufficient for practical use.

[0476] The silicon oxide-based inorganic filler is not particularly limited, and known materials can be used. Preferably, the filler contains SiO 2 or Si 3 Al as a solid particle of the structural unit, more preferably comprising SiO 2 or Si 3Solid particles having Al as a main component of the structural unit. Here, the main component refers to a component that accounts for 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more in the silicon oxide-based inorganic filler.

[0477] As specific silicon oxide-based inorganic fillers, inorganic fibrous materials such as silicon oxide, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber can be cited, but not limited to. In addition, a silicon oxide-based inorganic filler, a mixture of a silicon oxide-based inorganic filler and an inorganic filler other than silicon oxide-based inorganic fillers whose surfaces have been hydrophobized can also be cited. Among these, silicon oxide and glass fiber are preferred from aspects such as strength and wear resistance, and silicon oxide is more preferred. As silicon oxide, for example, dry silicon oxide, wet silicon oxide, and synthetic silicate silicon oxide can be cited. Among these silicon oxides, wet silicon oxide is preferred from the aspect of the improvement effect of the breaking strength and the excellent balance of the anti-wet skidability.

[0478] From the viewpoint of obtaining practically good wear resistance and breaking strength of the rubber composition, the nitrogen adsorption specific surface area of ​​the silica-based inorganic filler determined by the BET adsorption method is preferably 100 m 2 / g above 300m 2 / g or less, more preferably 170m 2 / g above 250m 2 / g or less. In addition, the specific surface area can be relatively small (for example, the specific surface area is 200m 2 / g or less) and a silicon oxide-based inorganic filler with a relatively large specific surface area (e.g., 200 m 2 / g or more) of a silicon oxide-based inorganic filler. In this embodiment, in particular, when using a relatively large specific surface area (e.g., 200 m 2 In the case of a silicon oxide-based inorganic filler of 0.1% to 0.1% (wt. / g or more), the dispersibility of silicon oxide in the composition containing the above-mentioned conjugated diene polymer is improved, which has an effect of improving wear resistance in particular, and tends to be able to achieve a high balance between good breaking strength and low hysteresis loss.

[0479] 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, relative to 100 parts by mass of the rubber component containing the conjugated diene polymer, 100 parts by mass. In the rubber composition of the present embodiment, the content of the silica-based inorganic filler is 5.0 parts by mass or more relative to 100 parts by mass of the rubber component from the perspective of showing the effect of adding the inorganic filler, and the content of the silica-based inorganic filler is 150 parts by mass or less relative to 100 parts by mass of the rubber component from the perspective of fully dispersing the inorganic filler and making the processability and mechanical strength of the composition sufficient in practical use.

[0480] Examples of carbon black include, but are not limited to, various grades of carbon black such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area of ​​50 m 2 / g or more and a dibutyl phthalate (DBP) oil absorption of 80mL / 100g or less.

[0481] In the rubber composition of the present embodiment, the content of carbon black 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 further preferably 5.0 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the rubber component containing the conjugated diene polymer, 100 parts by mass. In the rubber composition of the present embodiment, the content of carbon black is preferably 0.5 parts by mass or more relative to 100 parts by mass of the rubber component from the perspective of exhibiting the performance required in the application of tires, such as dry grip performance and conductivity, and is preferably 100 parts by mass or less relative to 100 parts by mass of the rubber component from the perspective of dispersibility.

[0482] The metal oxide refers to solid particles having a chemical formula of MxOy (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) as a main component of the structural unit.

[0483] Examples of the metal oxide include, but are not limited to, aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide.

[0484] Examples of the metal hydroxide include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0485] The rubber composition of the present embodiment may include a silane coupling agent. The silane coupling agent has the function of making the interaction between the rubber component and the inorganic filler close, and preferably has a group having affinity or binding properties for the rubber component and the silica-based inorganic filler, respectively, and a compound having a sulfur-bonded portion and an alkoxysilyl or silanol portion in one molecule. Such a compound is not particularly limited, and examples thereof include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0486] In the rubber composition of the present embodiment, the content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and further preferably 1.0 to 15 parts by mass, relative to 100 parts by mass of the inorganic filler. When the content of the silane coupling agent is within the above range, there is a tendency that the above-mentioned addition effect of the silane coupling agent can be made more significant.

[0487] The rubber composition of the present embodiment may contain a rubber softener from the viewpoint of improving its processability.

[0488] The amount of the rubber softener added is expressed as the total amount of the rubber softener previously contained in the conjugated diene polymer and other rubbery polymers and added when preparing the rubber composition, relative to 100 parts by mass of the rubber component containing the conjugated diene polymer.

[0489] As the rubber softener, mineral oil or a liquid or low molecular weight synthetic softener is suitable.

[0490] The mineral oil-based rubber softener called process oil or extender oil used to soften, increase volume and improve processability of rubber is a mixture of aromatic rings, cycloalkane rings and paraffin chains. The substances whose carbon atoms of paraffin chains account for more than 50% of all carbons are called paraffin series, the substances whose carbon atoms of cycloalkane rings account for more than 30% and less than 45% of all carbons are called cycloalkane series, and the substances whose aromatic carbon atoms account for more than 30% of all carbons are called aromatic series. In the case where the conjugated diene polymer of the present embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, it is preferred that the rubber softener used has a moderate aromatic content because its affinity with the copolymer is good.

[0491] In the rubber composition of the present embodiment, the content of the rubber softener is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and further preferably 30 to 90 parts by mass, relative to 100 parts by mass of the rubber component. When the content of the rubber softener is 100 parts by mass or less relative to 100 parts by mass of the rubber component, there is a tendency to suppress bleeding and suppress stickiness on the surface of the rubber composition.

[0492] Regarding the method of mixing the conjugated diene polymer with other rubber-like polymers, silicon oxide-based inorganic fillers, carbon black or other fillers, silane coupling agents, rubber softeners and other additives, it can be cited but not limited to, for example, a melt-mixing method using a common mixer such as an open mill, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, a multi-screw extruder, etc., and a method of heating and removing the solvent after each component is dissolved and mixed. Among these, from the aspect of productivity and good mixing properties, the melt-mixing method performed by rollers, Banbury mixers, kneaders, and extruders is preferably used. In addition, any one of the methods of mixing the rubber component with other fillers, silane coupling agents, and additives at one time and mixing them several times can also be applied.

[0493] The rubber composition of the present embodiment can be made into a vulcanized composition by vulcanization treatment with a vulcanizing agent. As the vulcanizing agent, free radical initiators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur-containing compounds can be cited but are not limited to them. Sulfur-containing compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfide compounds, etc. In the rubber composition of the present embodiment, the content of the vulcanizing agent is preferably 0.01 mass parts to 20 mass parts, more preferably 0.1 mass parts to 15 mass parts, relative to 100 mass parts of the rubber component. As a vulcanization method, an existing known method can be applied, and the vulcanization temperature is preferably 120°C to 200°C, more preferably 140°C to 180°C.

[0494] During vulcanization, a vulcanization accelerator can be used as required. As a vulcanization accelerator, existing known materials can be used, and examples thereof include but are not limited to sulfonamide, guanidine, thiuram, aldehyde-amine, aldehyde-ammonia, thiazole, thiourea, and dithiocarbamate vulcanization accelerators. In addition, as a vulcanization aid, examples thereof include but are not limited to zinc white and stearic acid. The content of the vulcanization accelerator is preferably 0.01 mass parts or more and 20 mass parts or less, and more preferably 0.1 mass parts or more and 15 mass parts or less relative to 100 mass parts of the rubber component.

[0495] In the rubber composition of the present embodiment, various additives such as other softeners and fillers other than the above, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, lubricants, etc. can be used within the scope that does not harm the purpose of the present embodiment. As other softeners, known softeners can be used. As other fillers, there is no particular limitation, specifically, for example, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate can be cited. As the above-mentioned heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, known materials can be used respectively.

[0496] The rubber composition of the present embodiment is suitable as a rubber composition for a tire. That is, the tire of the present embodiment is formed using the rubber composition.

[0497] The rubber composition for tires can be applied to various parts of tires such as treads, tire carcasses, bead, and bead portions of various tires such as fuel-saving tires, all-season tires, high-performance tires, and studless tires, but is not limited thereto. In particular, the rubber composition for tires has excellent wear resistance, breaking strength, and a balance between low hysteresis loss and wet skid resistance after being made into a vulcanized material, and is therefore suitable for use as a tread for fuel-saving tires and high-performance tires.

[0498] Example

[0499] The present embodiment will be described in more detail below with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.

[0500] Various physical properties in Examples and Comparative Examples were measured by the methods shown below.

[0501] (Physical Property 1) Polymer Mooney Viscosity

[0502] A conjugated diene polymer or a conjugated diene polymer coupled with a nitrogen-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 (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) with an L-shaped rotor in accordance with ISO289.

[0503] The measurement temperature was 110° C. when a conjugated diene polymer was used as a sample, and was 100° C. when a coupled conjugated diene polymer was used as a sample.

[0504] 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 as the Mooney viscosity (ML (1+4) ).

[0505] (Physical Property 2) Mooney Stress Relaxation Rate

[0506] A conjugated diene polymer or a coupled conjugated diene polymer is used as a sample, and the Mooney viscosity is measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with ISO289 using an L-shaped rotor. The rotation of the rotor is then stopped immediately, and the torque is recorded in Mooney units every 0.1 seconds from 1.6 seconds to 5 seconds after the stop. The torque and time (seconds) are plotted in double logarithms, and the slope of the straight line at this time is calculated, and its absolute value is taken as the Mooney stress relaxation rate (MSR).

[0507] (Physical Property 3) Degree of Branching (Bn)

[0508] The degree of branching (Bn) of the conjugated diene polymer was measured by the GPC-light scattering method with a viscosity detector as follows. The coupled conjugated diene polymer was used as a sample, and a gel permeation chromatography (GPC) measuring device (trade name "GPCmax VE-2001" manufactured by Malvern) connected to three columns with polystyrene gel as a filler was used for measurement, and three detectors were connected in order: a light scattering detector, an RI detector, and a viscosity detector (trade name "TDA305" manufactured by Malvern) to perform the measurement. Based on standard polystyrene, the absolute molecular weight was obtained from the results of the light scattering detector and the RI detector, and the intrinsic viscosity was obtained from the results of the RI detector and the viscosity detector.

[0509] Assume that the linear polymer follows the 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. It should be noted that, in the formula, M represents the absolute molecular weight.

[0510] Thereafter, the obtained shrinkage factor (g') was used to calculate the degree of branching (Bn) defined as g' = 6Bn / {(Bn+1)(Bn+2)}.

[0511] Tetrahydrofuran (hereinafter also referred to as "THF") added with 5 mmol / L of triethylamine was used as the eluent.

[0512] As columns, trade names "TSKgel G4000HXL", "TSKgel G5000HXL" and "TSKgel G6000HXL" manufactured by Tosoh Corporation were connected and used.

[0513] 20 mg of a sample for measurement was dissolved in 10 mL of THF to prepare a measurement solution. 100 μL of the measurement solution was injected into a GPC measurement device and measurement was performed under the conditions of an oven temperature of 40° C. and a THF flow rate of 1 mL / min.

[0514] [Degree of branching of polymer of 1 / 2Hi (Bn)]

[0515] The chromatogram of the absolute molecular weight is obtained based on the solution viscosity and the light scattering method using the GPC-light scattering method with a viscosity detector in the same manner as the measurement conditions for the above-mentioned degree of branching (Bn).

[0516] The degree of branching (Bn) of the polymer with the highest absolute molecular weight among at least two absolute molecular weights when the height in the absolute molecular weight curve is 1 / 2 of Hi (1 / 2Hi) is calculated according to the method for measuring the degree of branching (Bn) using the height of the peak top in the absolute molecular weight chromatogram (absolute molecular weight curve) (wherein, when there are multiple peak tops in the absolute molecular weight curve, the height of the peak top with the largest absolute molecular weight) Hi as a reference.

[0517] (Physical Property 4) Molecular Weight

[0518] Measurement condition 1: Using a conjugated diene polymer or a coupled conjugated diene polymer as a sample, a GPC measuring apparatus (trade name "HLC-8320GPC" manufactured by Tosoh Corporation) connected to three columns using polystyrene gel as a filler is used, and a chromatogram is measured using an RI detector (trade name "HLC8020" manufactured by Tosoh Corporation), and the weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) are calculated based on a calibration curve obtained using standard polystyrene.

[0519] THF (tetrahydrofuran) containing 5 mmol / L triethylamine was used as the eluent. Three columns of "TSKgel SuperMultiporeHZ-H" manufactured by Tosoh Corporation were connected, and a "TSKguardcolumn SuperMP(HZ)-H" manufactured by Tosoh Corporation was connected to the front of the column as a guard column.

[0520] 10 mg of a measurement sample was dissolved in 10 mL of THF to prepare a measurement solution, 10 μL of the measurement solution was injected into a GPC measurement device, and measurement was performed under the conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL / min.

[0521] Among the various samples measured under the above measurement condition 1, the samples with a molecular weight distribution (Mw / Mn) value of less than 1.6 were measured under the following measurement condition 2. The samples whose molecular weight distribution value was 1.6 or more when measured under measurement condition 1 were measured under measurement condition 1.

[0522] Measurement condition 2: Using a conjugated diene polymer or a coupled conjugated diene polymer as a sample, a chromatogram is measured using a GPC measuring apparatus connected to three columns using polystyrene gel as a filler, and the weight average molecular weight (Mw) and number average molecular weight (Mn) are determined based on a calibration curve obtained using standard polystyrene.

[0523] THF to which 5 mmol / L triethylamine was added was used as the eluent. For the column, a guard column with the trade name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation was used, and a column with the trade names "TSKgel SuperH5000", "TSKgel SuperH6000" and "TSKgel SuperH7000" manufactured by Tosoh Corporation was used.

[0524] An RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) was used at an oven temperature of 40°C and a THF flow rate of 0.6 mL / min. 10 mg of a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into the GPC measurement apparatus for measurement.

[0525] The sample whose molecular weight distribution value was less than 1.6 when measured under the measurement condition 1 was measured under the measurement condition 2.

[0526] (Physical Property 5) Modification Rate

[0527] The modification rate of the conjugated diene polymer was measured by the column adsorption GPC method as follows: The coupled conjugated diene polymer was used as a sample, and the measurement was performed by utilizing the property that the modified basic polymer component is adsorbed on a GPC column using a silica gel as a filler.

[0528] The adsorption amount on the silica column was measured from the difference between the chromatogram obtained by measuring a sample solution containing the sample and low molecular weight internal standard polystyrene using a polystyrene column and the chromatogram obtained by measuring using a silica column, and the modification rate was obtained.

[0529] Specifically, as follows: In addition, for samples measured using the measurement condition 1 of the above (physical property 4) and having a molecular weight distribution value of 1.6 or more, the following measurement condition 3 is used for measurement; for samples having a molecular weight distribution value of less than 1.6, the following measurement condition 4 is used for measurement.

[0530] 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.

[0531] Measurement condition 3: GPC measurement conditions using a polystyrene column:

[0532] The HLC-8320GPC manufactured by Tosoh Corporation was used, THF with 5 mmol / L triethylamine added was used as the eluent, 10 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 box temperature of 40°C and a THF flow rate of 0.35 mL / min. As for the column, three TSKgelSuperMultiporeHZ-H manufactured by Tosoh Corporation were connected, and a TSKguard column SuperMP(HZ)-H manufactured by Tosoh Corporation was connected to the front section as a guard column for use.

[0533] Measurement condition 4: THF with 5 mmol / L triethylamine added was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. As for the column, the protective column used the trade name "TSK guard column SuperH-H" manufactured by Tosoh Corporation, and the column used the trade name "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgelSuperH7000" manufactured by Tosoh Corporation. The chromatogram was obtained by using an RI detector (HLC8020 manufactured by Tosoh Corporation) at a column box temperature of 40°C and a THF flow rate of 0.6 mL / min.

[0534] GPC measurement conditions using silica columns: Use the product name "HLC-8320GPC" manufactured by Tosoh Corporation, use THF as the eluent, inject 50 μL of the sample solution into the device, and use the RI detector to obtain a chromatogram under the conditions of a column box temperature of 40°C and a THF flow rate of 0.5 ml / min. As for the column, the product names "Zorbax PSM-1000S", "PSM-300S", and "PSM-60S" were connected and used, and the product name "DIOL4.6×12.5mm5micron" was connected to the front section as a protective column.

[0535] Calculation method of modification rate: suppose the total peak area of ​​the chromatogram using a polystyrene column is 100, the peak area of ​​the sample is P1, and the peak area of ​​the standard polystyrene is P2; suppose the total peak area of ​​the chromatogram using a silica column is 100, the peak area of ​​the sample is P3, and the peak area of ​​the standard polystyrene is P4, and the modification rate (%) is calculated by the following formula.

[0536] Modification rate (%) = [1-(P2×P3) / (P1×P4)]×100

[0537] (where P1+P2=P3+P4=100)

[0538] (Physical Property 6) Bonded Styrene Amount

[0539] A coupled conjugated diene polymer not containing a rubber softener was used as a sample, and 100 mg of the sample was fixed to 100 mL using chloroform, and the sample was dissolved to prepare a measurement sample. The amount of bonded styrene (mass %) relative to 100% by mass of the coupled conjugated diene polymer as a sample was measured by the absorption of the phenyl group of styrene at an ultraviolet absorption wavelength (near 254 nm) (measuring device: spectrophotometer "UV-2450" manufactured by Shimadzu Corporation).

[0540] (Physical Property 7) Microstructure of Butadiene Part (1,2-vinyl Bond Amount)

[0541] A coupled conjugated diene polymer containing no 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. A solution dish was used at 600 to 1000 cm -1 The infrared spectrum was measured in a range of , and the microstructure of the butadiene part, i.e., the amount of 1,2-vinyl bonds (mol %), was determined based on the absorbance at a specified wave number according to the calculation formula of the Hampton method (the method described in RR Hampton, Analytical Chemistry 21, 923 (1949)) (measuring device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

[0542] (Physical Property 8) Molecular weight measured by GPC-light scattering method (absolute molecular weight)

[0543] The coupled conjugated diene polymer was used as a sample, and a chromatogram was measured using a GPC-light scattering measuring apparatus connected to three columns using polystyrene gel as a filler, and the weight average molecular weight (Mw-i) (also called "absolute molecular weight") was calculated based on solution viscosity and the light scattering method.

[0544] As the eluent, a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mL of triethylamine with 1 L of tetrahydrofuran) was used.

[0545] As the column, a guard column: trade name "TSK guard column HHR-H" manufactured by Tosoh Corporation and a column: trade name "TSKgel G6000HHR", "TSKgel G5000HHR" and "TSKgel G4000HHR" manufactured by Tosoh Corporation were connected and used.

[0546] A GPC-light scattering measuring apparatus (trade name "Viscotek TDAmax" manufactured by Malvern) was used at an oven temperature of 40°C and a THF flow rate of 1.0 mL / min. 10 mg of a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into the GPC measuring apparatus for measurement.

[0547] (Example 1) Coupling of conjugated diene polymer (Sample 1)

[0548] Two tank-type pressure vessels equipped with a stirrer and a jacket for temperature control were connected as a polymerization reactor. The tank-type pressure vessel is a tank-type reactor with a stirrer having an internal volume of 10 L, a ratio (L / D) of the internal height (L) to the diameter (D) of 4.0, an inlet at the bottom, and an outlet at the top.

[0549] 1,3-butadiene from which water had been removed in advance was mixed at 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. A static mixer was set in the middle of the pipe supplying the mixed solution to the inlet of the reactor, and n-butyl lithium for inert treatment of residual impurities was added to the static mixer at 0.103 mmol / min, mixed, and continuously supplied to the bottom of the reactor. Further, 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was supplied at a rate of 0.081 mmol / min, and n-butyl lithium as a polymerization initiator was supplied at a rate of 0.143 mmol / min to the bottom of the first reactor that was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C.

[0550] The polymer solution was continuously extracted from the top of the first reactor and continuously supplied to the bottom of the second reactor, and the reaction was continued at 70°C, and further supplied to the static mixer from the top of the second reactor. After the polymerization was fully stabilized, 1,3-butadiene and styrene were copolymerized while 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 from the bottom of the second reactor to perform polymerization reaction and branching reaction to obtain a conjugated diene polymer having a main chain branch structure. After the polymerization reaction and branching reaction were stabilized, a small amount of the conjugated diene polymer solution before the addition of the coupling agent was extracted, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of the polymer, and then the solvent was removed, and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 1-1.

[0551] Next, tetraethoxysilane (abbreviated as "A" in the table) as a coupling agent was continuously added to the polymer solution flowing out of the outlet of the reactor at a rate of 0.0480 mmol / min, and a static mixer was used to mix and perform a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out of 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. The conjugated diene polymer solution after the coupling reaction was extracted in small amounts, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of the polymer, and then the solvent was removed, and the amount of bonded styrene (physical property 6) and the microstructure of the butadiene part (1,2-vinyl bonding amount: physical property 7) were measured. The measurement results are shown in Table 1-1.

[0552] Next, an antioxidant (BHT) is continuously added to the polymer solution after the coupling reaction at 0.055 g / min (n-hexane solution) in a manner of 0.2 g per 100 g of polymer to terminate the coupling reaction. SRAE oil (JOMO Process NC140 manufactured by JX Nippon Mining and Petrochemical Corporation) is continuously added as a rubber softener in a manner of 25.0 g relative to 100 g of the polymer together with the antioxidant, and mixed using a static mixer. The solvent is removed by stripping to obtain a coupled conjugated diene polymer (sample 1) having a 4-branch structure from a branching agent (hereinafter also described as "branching agent structure (1)") of a compound represented by the following formula (1) on a portion of the main chain, and having a 3-branch star-shaped polymer structure from a coupling agent. The physical properties of sample 1 are shown in Table 1-1. It should be noted that, 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 the coupled conjugated diene polymer was identified by comparing the molecular weight measured by GPC with the degree of branching measured by GPC with a viscometer. The structure of each sample was identified in the same manner below.

[0553] [Chemistry 20]

[0554]

[0555] (In formula (1), R 1 It represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a part of it may have a branched structure.

[0556] R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure.

[0557] When there are multiple R1 ~R 3 Each one is independent.

[0558] X 1 represents an independent halogen atom.

[0559] m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3.)

[0560] (Example 2) Coupling of conjugated diene polymer (Sample 2)

[0561] The same operation as in Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table) and the addition amount thereof was changed to 0.0360 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 2) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 2 are shown in Table 1-1.

[0562] (Example 3) Coupling of conjugated diene polymer (Sample 3)

[0563] The same operation as in Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane (abbreviated as "C" in the table) and the addition amount thereof was changed to 0.0360 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 3) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 3 are shown in Table 1-1.

[0564] (Example 4) Coupling of conjugated diene polymer (Sample 4)

[0565] The same operation as in Example 1 was performed 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 addition amount thereof was changed to 0.0360 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 4) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 4 are shown in Table 1-1.

[0566] (Example 5) Coupling of conjugated diene polymer (Sample 5)

[0567] The same operation as in Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to tris(3-trimethoxysilylpropyl)amine (abbreviated as "E" in the table) and the addition amount was changed to 0.0250 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 5) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a six-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 5 are shown in Table 1-1.

[0568] (Example 6) Coupling of conjugated diene polymer (Sample 6)

[0569] The same operation as in Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0190 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 6) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 6 are shown in Table 1-1.

[0570] (Example 7) Coupling of conjugated diene polymer (Sample 7)

[0571] The same operation as in Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0160 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 7) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 7 are shown in Table 1-1.

[0572] (Example 8) Coupling of conjugated diene polymer (Sample 8)

[0573] The same operation as in Example 1 was performed except that the addition rate of 1,3-butadiene was changed from 18.6 g / min to 24.3 g / min, the addition rate of styrene was changed from 10.0 g / min to 4.3 g / min, the addition rate of 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was changed from 0.081 mmol / min to 0.044 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0160 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 8) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 8 are shown in Table 1-1.

[0574] (Example 9) Coupling of conjugated diene polymer (Sample 9)

[0575] The same operation as in Example 1 was performed except that the addition rate of 1,3-butadiene was changed from 18.6 g / min to 17.1 g / min, the addition rate of styrene was changed from 10.0 g / min to 11.5 g / min, the addition rate of 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was changed from 0.081 mmol / min to 0.089 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0160 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 9) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and an eight-branch star polymer structure derived from the coupling agent. The physical properties of Sample 9 are shown in Table 1-1.

[0576] (Example 10) Coupling of conjugated diene polymer (Sample 10)

[0577] The same operation as in Example 1 was performed except that the addition rate of 2,2-bis(2-tetrahydrofuranyl)propane as a polar substance was changed from 0.081 mmol / min to 0.200 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount was changed to 0.0160 mmol / min, to obtain a coupled conjugated diene polymer (Sample 10) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 10 are shown in Table 1-2.

[0578] (Example 10a) Coupling of conjugated diene polymer (Sample 10a)

[0579] The same operation as in Example 1 was performed except that the addition rate of 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was changed from 0.081 mmol / min to 0.112 mmol / min, the addition rate of n-butyllithium as a polymerization initiator was changed from 0.143 mmol / min to 0.199 mmol / min, the addition amount of trimethoxy(4-vinylphenyl)silane as a branching agent was changed from 0.0190 mmol / min to 0.0248 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0210 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 10a) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and an eight-branch star polymer structure derived from the coupling agent. The physical properties of Sample 10a are shown in Table 1-2.

[0580] (Example 10b) Coupling of conjugated diene polymer (Sample 10b)

[0581] The same operation as in Example 1 was performed except that the addition rate of 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was changed from 0.081 mmol / min to 0.112 mmol / min, the addition rate of n-butyllithium as a polymerization initiator was changed from 0.143 mmol / min to 0.199 mmol / min, the addition amount of trimethoxy(4-vinylphenyl)silane as a branching agent was changed from 0.0190 mmol / min to 0.0248 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0184 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 10b) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and an eight-branch star polymer structure derived from the coupling agent. The physical properties of Sample 10b are shown in Table 1-2.

[0582] (Example 10c) Coupling of conjugated diene polymer (Sample 10c)

[0583] The same operation as in Example 1 was performed except that the addition rate of 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was changed from 0.081 mmol / min to 0.060 mmol / min, the addition rate of n-butyllithium as a polymerization initiator was changed from 0.143 mmol / min to 0.101 mmol / min, the addition amount of trimethoxy(4-vinylphenyl)silane as a branching agent was changed from 0.0190 mmol / min to 0.0140 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0118 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 10c) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and an eight-branch star polymer structure derived from the coupling agent. The physical properties of Sample 10c are shown in Table 1-2.

[0584] (Example 11) Coupling of conjugated diene polymer (Sample 11)

[0585] The branching agent was changed from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), and the addition amount thereof was changed to 0.0350 mmol / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table), and the addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 11) having a 2-branch structure derived from the branching agent structure (1) on a part of the main chain and a 4-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 11 are shown in Table 1-2.

[0586] (Example 12) Coupling of conjugated diene polymer (Sample 12)

[0587] The branching agent was changed from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), and the addition amount thereof was changed to 0.0350 mmol / min. 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 addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 12) having a two-branch structure derived from the branching agent structure (1) on a part of the main chain and a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 12 are shown in Table 1-2.

[0588] (Example 13) Coupling of conjugated diene polymer (Sample 13)

[0589] The branching agent was changed from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), and the addition amount thereof was changed to 0.0350 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propylenediamine (abbreviated as "F" in the table), and the addition amount thereof was changed to 0.0160 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 13) having a 2-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 13 are shown in Table 1-2.

[0590] (Example 14) Coupling of conjugated diene polymer (Sample 14)

[0591] 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 addition amount thereof was changed to 0.0120 mmol / min. The coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table), and the addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 14) having a three-branch structure derived from a branching agent (hereinafter also referred to as "branching agent structure (2)") derived from a compound represented by the following formula (2) on a part of the main chain and having a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 14 are shown in Table 1-2.

[0592] [Chemistry 21]

[0593]

[0594] (In formula (2), R 2 ~R 5 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and a part of them may have a branched structure. 2 ~R 5 Each one is independent.

[0595] X 2 ~X 3 represents an independent halogen atom.

[0596] m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3. (m+n+l) represents 3. a represents an integer from 0 to 2, b represents an integer from 0 to 3, and c represents an integer from 0 to 3. (a+b+c) represents 3. )

[0597] (Example 15) Coupling of conjugated diene polymer (Sample 15)

[0598] 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 addition amount thereof was changed to 0.0120 mmol / min. 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 addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 15) having a three-branch structure derived from the branching agent structure (2) on a part of the main chain and a four-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 15 are shown in Table 1-2.

[0599] (Example 16) Coupling of conjugated diene polymer (Sample 16)

[0600] 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 addition amount thereof was changed to 0.0120 mmol / min. The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), and the addition amount thereof was changed to 0.0160 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 16) having a 3-branch structure derived from the branching agent structure (2) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 16 are shown in Table 1-2.

[0601] (Example 17) Coupling of conjugated diene polymer (Sample 17)

[0602] 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 addition amount thereof was changed to 0.0210 mmol / min. The coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table), and the addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 17) having a 7-branch structure derived from the branching agent structure (2) on a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of Sample 17 are shown in Table 2-1.

[0603] (Example 18) Coupling of conjugated diene polymer (Sample 18)

[0604] 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 addition amount thereof was changed to 0.0210 mmol / min. 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 addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 18) having a 7-branch structure derived from the branching agent structure (2) on a part of the main chain and a 4-branch star polymer structure derived from the coupling agent. The physical properties of Sample 18 are shown in Table 2-1.

[0605] (Example 19) Coupling of conjugated diene polymer (Sample 19)

[0606] 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 addition amount thereof was changed to 0.0210 mmol / min. The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), and the addition amount thereof was changed to 0.0160 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 19) having a 7-branch structure derived from the branching agent structure (2) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 19 are shown in Table 2-1.

[0607] (Example 20) Coupling of conjugated diene polymer (Sample 20)

[0608] The branching agent was changed from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table), and the addition amount thereof was changed to 0.0190 mmol / min, and the coupling agent was changed from tetraethoxysilane to 1,2-bis(triethoxysilyl)ethane (abbreviated as "B" in the table), and the addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 20) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 20 are shown in Table 2-1.

[0609] (Example 21) Coupling of conjugated diene polymer (Sample 21)

[0610] The branching agent was changed from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table), and the addition amount thereof was changed to 0.0190 mmol / min. 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 addition amount thereof was changed to 0.0360 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 21) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 21 are shown in Table 2-1.

[0611] (Example 22) Coupling of conjugated diene polymer (Sample 22)

[0612] The branching agent was changed from trimethoxy(4-vinylphenyl)silane to trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table), and the addition amount thereof was changed to 0.0190 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), and the addition amount thereof was changed to 0.0160 mmol / min. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 22) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 22 are shown in Table 2-1.

[0613] (Example 23) Coupling of conjugated diene polymer (Sample 23)

[0614] The same operation as in Example 1 was performed except that the addition amount of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) as a branching agent was changed from 0.0190 mmol / min to 0.0100 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0190 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 23) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 23 are shown in Table 2-1.

[0615] (Example 24) Coupling of conjugated diene polymer (Sample 24)

[0616] The same operation as in Example 1 was performed except that the addition amount of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) as a branching agent was changed from 0.0190 mmol / min to 0.0250 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0190 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 24) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 24 are shown in Table 2-1.

[0617] (Example 25) Coupling of conjugated diene polymer (Sample 25)

[0618] The same operation as in Example 1 was performed except that the addition amount of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) as a branching agent was changed from 0.0190 mmol / min to 0.0350 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount thereof was changed to 0.0190 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 25) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 25 are shown in Table 2-2.

[0619] (Example 26) Coupling of conjugated diene polymer (Sample 26)

[0620] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), the addition amount thereof was changed to 0.0190 mmol / min, and the SRAE oil added as the rubber softener was changed to liquid rubber (liquid polybutadiene LBR-302 manufactured by KURARAY Co., Ltd.), and the same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 26) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 26 are shown in Table 2-2.

[0621] (Example 27) Coupling of conjugated diene polymer (Sample 27)

[0622] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), the addition amount thereof was changed to 0.0190 mmol / min, and the SRAE oil added as a rubber softener was changed to a resin (terpene resin YS Resin PX1250 manufactured by YASUHARA CHEMICAL Co., Ltd.), and the same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 27) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and an eight-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 27 are shown in Table 2-2.

[0623] (Example 28) Coupling of conjugated diene polymer (Sample 28)

[0624] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), the addition amount thereof was changed to 0.0190 mmol / min, and the SRAE oil added as a rubber softener was changed to cycloparaffin oil (cycloparaffin oil Nytex810 manufactured by Nynas), and the same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 28) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 28 are shown in Table 2-2.

[0625] (Example 29) Coupling of conjugated diene polymer (Sample 29)

[0626] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), and the addition amount thereof was changed to 0.0190 mmol / min. No rubber softener was added. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 29) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 29 are shown in Table 2-2.

[0627] (Example 30) Coupling of conjugated diene polymer (Sample 30)

[0628] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), the addition amount thereof was changed to 0.0190 mmol / min, and the addition amount of SRAE oil added as a rubber softener was changed from 25.0 g to 37.5 g per 100 g of the polymer. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 30) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 30 are shown in Table 2-2.

[0629] (Example 30a) Coupling of conjugated diene polymer (Sample 30a)

[0630] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table), the addition amount thereof was changed to 0.0190 mmol / min, and the addition amount of SRAE oil added as a rubber softener was changed from 25.0 g to 50.0 g per 100 g of the polymer. The same operation as in Example 1 was performed to obtain a coupled conjugated diene polymer (Sample 30a) having a 4-branch structure derived from the branching agent structure (1) on a part of the main chain and an 8-branch star polymer structure derived from the coupling agent. The physical properties of Sample 30a are shown in Table 2-2.

[0631] (Example 30b) Conjugated diene polymer (Sample 30b)

[0632] No branching agent was added, the coupling agent was changed from tetraethoxysilane to the coupling agent shown in the following (S-1) (abbreviated as "G" in the table), and the addition amount was changed to 0.0152 mmol / min. The same operation as Example 1 was performed except that there was no main chain branch from the branching agent and a coupled conjugated diene polymer (sample 30a) having a 10-branch star-shaped polymer structure from the coupling agent was obtained. The physical properties of sample 30a are shown in Table 2-2.

[0633] [Chemistry 22]

[0634]

[0635] (Comparative Example 1) Coupling of conjugated diene polymer (Sample 31)

[0636] Two tank-type pressure vessels equipped with a stirrer and a jacket for temperature control were connected as a polymerization reactor. The tank-type pressure vessel is a tank-type reactor with a stirrer having an internal volume of 10 L, a ratio (L / D) of the internal height (L) to the diameter (D) of 4.0, an inlet at the bottom, and an outlet at the top.

[0637] 1,3-butadiene from which water had been removed in advance was mixed at 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. A static mixer was set in the middle of the pipe supplying the mixed solution to the inlet of the reactor, and n-butyl lithium for inert treatment of residual impurities was added to the static mixer at 0.103 mmol / min, mixed, and continuously supplied to the bottom of the reactor. Further, 2,2-bis(2-tetrahydrofuryl)propane as a polar substance was supplied at a rate of 0.081 mmol / min, and n-butyl lithium as a polymerization initiator was supplied at a rate of 0.143 mmol / min to the bottom of the first reactor that was vigorously mixed with a stirrer, and the temperature inside the reactor was maintained at 67°C.

[0638] The polymer solution was continuously drawn out from the top of the first reactor and continuously supplied to the bottom of the second reactor, and the reaction was continued at 70°C, and further supplied to the static mixer from the top of the second reactor. After the polymerization was sufficiently stable, a small amount of the polymer solution before the addition of the coupling agent was drawn out, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of the polymer, and then the solvent was removed, and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties are shown in Table 3.

[0639] Next, tetraethoxysilane (abbreviated as "A" in the table) as a coupling agent was continuously added to the polymer solution flowing out of the outlet of the reactor at a rate of 0.0480 mmol / min, and a static mixer was used to mix and carry out a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out of 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. The conjugated diene polymer solution after the coupling reaction was extracted in small amounts, and an antioxidant (BHT) was added in an amount of 0.2 g per 100 g of polymer, and then the solvent was removed, and the amount of bonded styrene (physical property 6) and the microstructure of the butadiene part (1,2-vinyl bonding amount: physical property 7) were measured. The measurement results are shown in Table 3.

[0640] Then, in the polymer solution after the coupling reaction, an antioxidant (BHT) is continuously added at 0.055 g / min (n-hexane solution) in a manner of 0.2 g per 100 g of polymer to terminate the coupling reaction. Together with the antioxidant, SRAE oil (JOMOProcess NC140 manufactured by JX Nippon Mining and Energy Co., Ltd.) is continuously added as a rubber softener in a manner of 25.0 g relative to 100 g of polymer, and mixed using a static mixer. The solvent is removed by stripping to obtain a coupled conjugated diene polymer (sample 31) having no main chain branching from a branching agent and a 3-branch star-shaped polymer structure from a coupling agent. The physical properties of sample 31 are shown in Table 3.

[0641] (Comparative Example 2) Coupling of conjugated diene polymer (Sample 32)

[0642] 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 addition amount was changed to 0.0360 mmol / min. The same operation as Comparative Example 1 was performed 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 addition amount was changed to 0.0360 mmol / min. A coupled conjugated diene polymer (Sample 32) having no main chain branch from the branching agent and having a four-branched star-shaped polymer structure from the coupling agent was obtained. The physical properties of Sample 32 are shown in Table 3.

[0643] (Comparative Example 3) Coupling of conjugated diene polymer (Sample 33)

[0644] The coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount was changed to 0.0190 mmol / min. The same operation as Comparative Example 1 was performed except that the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine and the addition amount was changed to 0.0190 mmol / min to obtain a coupled conjugated diene polymer (Sample 33) having no main chain branches from the branching agent and having an 8-branch star-shaped polymer structure from the coupling agent. The physical properties of Sample 33 are shown in Table 3.

[0645] (Comparative Example 3a) Conjugated diene polymer (Sample 33a)

[0646] The addition rate of 2,2-bis(2-tetrahydrofuranyl)propane as a polar substance was changed from 0.081 mmol / min to 0.182 mmol / min, the addition rate of n-butyl lithium as a polymerization initiator was changed from 0.143 mmol / min to 0.368 mmol / min, the coupling agent was changed from tetraethoxysilane to the coupling agent (S-1) used in Example 30a (abbreviated as "G" in the table), and the addition amount was changed to 0.0360 mmol / min. The same operation as Comparative Example 1 was performed except that the main chain branches from the branching agent were not obtained, and the coupled conjugated diene polymer (Sample 33a) having a 10-branch star polymer structure from the coupling agent was obtained. The physical properties of Sample 33a are shown in Table 3.

[0647] (Comparative Example 4) Conjugated diene polymer (Sample 34)

[0648] After the polymerization was sufficiently stabilized, 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. Except that no coupling agent was added, the same operation as in Comparative Example 1 was performed to obtain a conjugated diene polymer (Sample 34) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and not showing a star-shaped coupling structure derived from the coupling agent. The physical properties of Sample 34 are shown in Table 3.

[0649] (Comparative Example 5) Coupling of conjugated diene polymer (Sample 35)

[0650] After the polymerization was sufficiently stabilized, trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) as a branching agent was added from the bottom of the second reactor at a rate of 0.0190 mmol / min, and the addition amount of tetraethoxysilane (abbreviated as "A" in the table) as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. The same operation as in Comparative Example 1 was performed except that the reaction mixture was subjected to a reaction mixture reaction. A coupled conjugated diene polymer (Sample 35) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a three-branch star-shaped polymer structure derived from the coupling agent was obtained. The physical properties of Sample 35 are shown in Table 3.

[0651] (Comparative Example 6) Coupling of conjugated diene polymer (Sample 36)

[0652] After the polymerization was sufficiently stabilized, 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 the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propylenediamine (abbreviated as "F" in the table) and the addition amount was changed to 0.0038 mmol / min. The same operation as in Comparative Example 1 was performed except that the above-mentioned procedures were repeated to obtain a coupled conjugated diene polymer (Sample 36) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a partially eight-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 36 are shown in Table 3.

[0653] (Comparative Example 7) Coupling of conjugated diene polymer (Sample 37)

[0654] After the polymerization was sufficiently stabilized, dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table) was added as a branching agent from the bottom of the second reactor at a rate of 0.0350 mmol / min, and the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. The same operation as in Comparative Example 1 was performed except that the addition amount was changed from 0.0480 mmol / min to 0.0120 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 37) having a two-branch structure derived from the branching agent structure (1) on a part of the main chain and a three-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 37 are shown in Table 3.

[0655] (Comparative Example 8) Coupling of conjugated diene polymer (Sample 38)

[0656] After the polymerization was sufficiently stabilized, 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene (abbreviated as "BS-3" in the table) as a branching agent was added from the bottom of the second reactor at a rate of 0.0120 mmol / min, and the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. The same operation as Comparative Example 1 was performed except that the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 38) having a three-branch structure derived from the branching agent structure (2) on a part of the main chain and a partially three-branched star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 38 are shown in Table 3.

[0657] (Comparative Example 9) Coupling of conjugated diene polymer (Sample 39)

[0658] After the polymerization was sufficiently stabilized, 1,1-bis(4-trimethoxysilylphenyl)ethylene (abbreviated as "BS-4" in the table) as a branching agent was added from the bottom of the second reactor at a rate of 0.0210 mmol / min, and the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. The same operation as Comparative Example 1 was performed except that the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 39) having a 7-branch structure derived from the branching agent structure (2) on a part of the main chain and a partially 3-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 39 are shown in Table 3.

[0659] (Comparative Example 10) Coupling of conjugated diene polymer (Sample 40)

[0660] After the polymerization was sufficiently stabilized, trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" 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 the addition amount of tetraethoxysilane as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. The same operation as in Comparative Example 1 was performed except that the addition amount of tetraethoxysilane was changed from 0.0480 mmol / min to 0.0120 mmol / min, thereby obtaining a coupled conjugated diene polymer (Sample 40) having a four-branch structure derived from the branching agent structure (1) on a part of the main chain and a partially three-branch star-shaped polymer structure derived from the coupling agent. The physical properties of Sample 40 are shown in Table 3.

[0661]

[0662]

[0663]

[0664]

[0665]

[0666] (Examples 31 to 60, and Comparative Examples 11 to 20)

[0667] Samples 1 to 40 shown in Tables 1-1 to 3 were used as raw material rubbers, and rubber compositions containing the raw material rubbers were obtained in the following blending ratios.

[0668] (Rubber component)

[0669] · Coupled conjugated diene polymer (samples 1 to 40): 80 parts by mass (excluding the parts by mass of the rubber softener)

[0670] High cis polybutadiene (trade name "UBEPOLBR150" manufactured by Ube Industries, Ltd.): 20 parts by mass (blending conditions)

[0671] The amount of each compounding agent added is expressed in parts by mass relative to 100 parts by mass of the rubber component excluding the rubber softener.

[0672] Silicon oxide 1 (trade name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m 2 / g): 50.0 parts by mass

[0673] Silicon oxide 2 (trade name "Zeosil Premium 200MP" manufactured by Rhodia, nitrogen adsorption specific surface area 220 m 2 / g): 25.0 parts by mass

[0674] Carbon black (trade name "SEAST KH (N339)" manufactured by Tokai Tanso Co., Ltd.): 5.0 parts by mass

[0675] Silane coupling agent (trade name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass

[0676] SRAE oil (trade name "Process NC140" manufactured by JX Nippon Mining & Energy Corporation): 42.0 parts by mass (including the amount previously added as a rubber softener contained in samples 1 to 40)

[0677] Zinc white: 2.5 parts by mass

[0678] Stearic acid: 1.0 parts by mass

[0679] Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass

[0680] Sulfur: 2.2 parts by mass

[0681] Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazolylsulfenamide): 1.7 parts by mass

[0682] Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass

[0683] Total: 239.4 parts by mass

[0684] (Mixing method)

[0685] The above materials were kneaded by the following method to obtain a rubber composition. A closed mixer (content 0.3L) equipped with a temperature control device was used as the first stage of kneading to knead the raw rubber (samples 1 to 40), fillers (silicon oxide 1, silicon oxide 2, carbon black), silane coupling agent, SRAE oil, zinc white and stearic acid at a filling rate of 65% and a rotor speed of 30 to 50 rpm. At this time, the temperature of the closed mixer was controlled to obtain each rubber composition (mixed product) at a discharge temperature of 155 to 160°C.

[0686] Next, as the second stage of mixing, the above-obtained mixture is cooled to room temperature, an anti-aging agent is added, and mixing is performed again to improve the dispersion of silicon oxide. In this case, the discharge temperature of the mixture is also adjusted to 155-160°C by temperature control of the mixer. After cooling, as the third stage of mixing, sulfur and vulcanization accelerators 1 and 2 are added to an open mill set at 70°C for mixing. Thereafter, molding is performed and vulcanization is performed at 160°C for 20 minutes using a vulcanization press. The rubber composition before vulcanization and the rubber composition after vulcanization are evaluated. Specifically, the evaluation is performed by the following method. The results are shown in Tables 4-1 to 6.

[0687] (Evaluation 1) Mooney viscosity of compound

[0688] The mixture obtained after the second stage kneading and before the third stage kneading was used as a sample, and the viscosity was measured using a Mooney viscometer according to ISO289, after preheating at 130°C for 1 minute, rotating the rotor at 2 revolutions per minute for 4 minutes. The result of Comparative Example 11 was set to 100 and indexed. The smaller the index, the better the processability.

[0689] (Evaluation 2) Tensile strength and elongation at break

[0690] The tensile strength and elongation at break were measured according to the tensile test method of JIS K6251, and the result of Comparative Example 11 was indexed as 100. A larger index indicates better tensile strength and elongation at break (breaking strength).

[0691] (Evaluation 3) Wear resistance

[0692] The wear amount at a load of 44.4 N and 1000 revolutions was measured using an Akron wear tester (manufactured by Yasuda Seiki Co., Ltd.) in accordance with JIS K6264-2, and the result of Comparative Example 11 was indexed as 100. A larger index indicates better wear resistance.

[0693] (Evaluation 4) Viscoelastic parameters

[0694] Viscoelastic parameters were measured in a torsional vibration mode using a viscoelasticity tester "ARES" manufactured by Rheometric Scientific Co., Ltd. The result for the rubber composition of Comparative Example 11 was set to 100, and each measured value was indexed.

[0695] Tan δ measured at 0°C, 10 Hz frequency, and 1% strain is used as an index of wet grip performance. A larger index indicates better wet grip performance.

[0696] In addition, tan δ measured at 50° C., at a frequency of 10 Hz and a strain of 3% was used as an index of fuel efficiency. A smaller index indicates better fuel efficiency.

[0697] 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 the steering stability. A larger index indicates better steering stability.

[0698]

[0699]

[0700]

[0701] As shown in Tables 4-1 to 6, it was confirmed that, compared with Comparative Examples 11 to 20, Examples 31 to 60b had a low Mooney viscosity of the compound when preparing the sulfide, exhibited good processability, and had excellent wear resistance, handling stability, and breaking strength after preparing the sulfide, and had an excellent balance between low hysteresis loss and wet skid resistance.

[0702] This application is based on the Japanese patent application (Japanese Patent Application No. 2019-162042) filed on September 5, 2019, and its contents are incorporated into this specification as a reference.

[0703] Industrial Applicability

[0704] The conjugated diene polymer of the present invention has industrial applicability in the fields of tire treads, automobile interior and exterior products, anti-vibration rubber, conveyor belts, shoes, foams, and various industrial products.

Claims

1. A conjugated diene polymer, which is a copolymer of a conjugated diene compound and an aromatic vinyl compound, wherein: The Mooney viscosity measured at 100°C is 40 or more and 170 or less. The Mooney stress relaxation rate measured at 100°C is 0.239 or more and 0.35 or less. The degree of branching (Bn) determined by GPC-light scattering method with a viscosity detector is 8 or more, Contains nitrogen atoms.

2. The conjugated diene polymer according to claim 1, wherein The degree of branching (Bn) of the polymer having the highest absolute molecular weight among at least two absolute molecular weights when the height in the absolute molecular weight curve is 1 / 2 of Hi (1 / 2Hi) is 12 or more, based on the height Hi of the peak top in the absolute molecular weight curve obtained by the GPC-light scattering measurement method with a viscosity detector, wherein when there are multiple peak tops in the absolute molecular weight curve, the height of the peak top is the height of the peak top with the largest absolute molecular weight.

3. The conjugated diene polymer according to claim 1 or 2, wherein The modification rate measured by column adsorption GPC method, which represents the mass ratio of the conjugated diene polymer having a nitrogen atom-containing functional group relative to the total amount of the conjugated diene polymer, is 60% by mass or more.

4. The conjugated diene polymer according to claim 1 or 2, wherein The polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a main chain branch structure.

5. The conjugated diene polymer according to claim 1 or 2, wherein The polymer has a star-shaped polymer structure with more than three branches. At least one branch of the star-shaped structure has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and the portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group has a further main chain branch structure.

6. The conjugated diene polymer according to claim 4, wherein The portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group is a monomer unit based on a compound represented by the following formula (1) or (2), Having a branching point of a polymer chain derived from a monomer unit based on a compound represented by the following formula (1) or formula (2), [Chemistry 1] In formula (1), R 1 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and has no branched structure or has a branched structure in part; R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and has no branched structure or has a branched structure in part; When there are multiple R 1 ~R 3 Each is independent; X 1 represents an independent halogen atom; m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3; (m+n+l) represents 3; [Chemistry 2] In formula (2), R 2 ~R 5 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which has no branched structure or has a branched structure in part; when there are plural R 2 ~R 5 Each is independent; X 2 ~X 3 represents an independent halogen atom; m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3; (m+n+l) represents 3; a represents an integer from 0 to 2, b represents an integer from 0 to 3, c represents an integer from 0 to 3; (a+b+c) represents 3.

7. The conjugated diene polymer according to claim 6, which has a monomer unit based on a compound represented by the formula (1), wherein R 1 is a hydrogen atom, m=0. 8 . The conjugated diene polymer according to claim 6 , comprising a monomer unit based on a compound represented by the formula (2), wherein m=0 and b=0.

9. The conjugated diene polymer according to claim 6, which has a monomer unit based on a compound represented by the formula (1), wherein R 1 It is a hydrogen atom, m=0, l=0, n=3. 10 . The conjugated diene polymer according to claim 6 , comprising a monomer unit based on a compound represented by the formula (2), wherein m=0, l=0, n=3, a=0, b=0, and c=3.

11. The conjugated diene polymer according to any one of claims 1 to 2 and 6 to 10, wherein The amount of bonded aromatic vinyl groups in the conjugated diene polymer is 20% by mass or more and 45% by mass or less.

12. The conjugated diene polymer according to any one of claims 1 to 2 and 6 to 10, wherein In the conjugated diene polymer, the amount of vinyl bonds in the conjugated diene bond units is 20 mol% to 65 mol%.

13. The conjugated diene polymer according to any one of claims 1 to 2 and 6 to 10, wherein The conjugated diene polymer has a structure derived from any one of the compounds represented by formula (i) and (A) to (C), In formula (i), R is a hydrocarbon group having a valency of 2 or more, or a divalent or more organic group having at least one polar group selected from a polar group having oxygen, a polar group having sulfur, and a polar group having nitrogen; R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 They can be the same or different from each other; R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 They can be the same or different from each other; R 3 is a hydrocarbon group having 1 to 10 carbon atoms, or a structure of the following formula (ii); R 1 , R 2 , R 3 It can be a ring structure formed by mutual bonding; R 3 In the case of a hydrocarbon group, it may be a cyclic structure bonded to R; in the case of the above cyclic structure, it may be a cyclic structure bonded to R 3 The bonded N and R are directly bonded; n is an integer greater than 1, and m is an integer greater than 0 or 1; In formula (ii), R 1 , R 2 and R of the formula (i) 1 , R 2 Similarly, R 1 , R 2 They can be the same or different from each other; 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, and 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; when there are plural numbers, R 1 ~R 4 Each is independent; 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, and 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, (m+n+l) represents an integer of 4 or more; when there are plural numbers, R 1 ~R 6 Each is independent; In formula (C), R 12 ~R 14 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, and 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, and R 21 represents an alkyl group or a trialkylsilyl group having 1 to 20 carbon atoms; m represents an integer from 1 to 3, and p represents 1 or 2; When there are multiple R 12 ~R 22 , m and p are independent of each other and can be the same or different; i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, and (i+j+k) is an integer from 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.

14. The conjugated diene polymer according to claim 13, wherein In the formula (A), m represents 2, and n represents 3; In the formula (B), n, m and l all represent 3; In the formula (C), A is represented by any one of the following formulas (II) to (V); 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 there are plural B 1 Each is independent; 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, a represents an integer of 1 to 10; when there are plural of each, B 2 and B 3 Each is independent; 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; when there are plural B 4 Each is independent; 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; when there are plural B 5 Each one is independent.

15. The conjugated diene polymer according to claim 14, wherein In the formula (C), A is represented by the formula (II) or the formula (III), k represents 0, and in the formula (II) and the formula (III), a represents an integer of 2 to 10.

16. A method for producing a conjugated diene polymer, which is the method for producing a conjugated diene polymer according to any one of claims 1 to 15, in, The method has the following steps: A polymerization and branching step, using an organic lithium compound as a polymerization initiator, while polymerizing at least a conjugated diene compound, while adding a branching agent to obtain a conjugated diene polymer having a main chain branch structure; as well as The coupling step is to couple the conjugated diene polymer using a coupling agent.

17. The manufacturing method according to claim 16, wherein: The branching agent is a compound represented by the following formula (1) or formula (2), In formula (1), R 1 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and has no branched structure or has a branched structure in part; R 2 ~R 3 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and has no branched structure or has a branched structure in part; When there are multiple R 1 ~R 3 Each is independent; X 1 represents an independent halogen atom; m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3; (m+n+l) represents 3; In formula (2), R 2 ~R 5 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which has no branched structure or has a branched structure in part; when there are plural R 2 ~R 5 Each is independent; X 2 ~X 3 represents an independent halogen atom; m represents an integer from 0 to 2, n represents an integer from 0 to 3, and l represents an integer from 0 to 3; (m+n+l) represents 3; a represents an integer from 0 to 2, b represents an integer from 0 to 3, c represents an integer from 0 to 3; (a+b+c) represents 3.

18. The manufacturing method according to claim 17, wherein: The branching agent is a compound represented by the formula (1), wherein R 1 is a hydrogen atom, m=0.

19. The manufacturing method according to claim 17, wherein: The branching agent is a compound represented by the formula (2), wherein m=0 and b=0.

20. The manufacturing method according to claim 17, wherein: The branching agent is a compound represented by the formula (1), wherein R 1 It is a hydrogen atom, m=0, l=0, n=3.

21. The manufacturing method according to claim 17, wherein: The branching agent is a compound represented by the formula (2), wherein m=0, l=0, n=3, a=0, b=0, and c=3.

22. The manufacturing method according to claim 16, wherein: The coupling agent is a reactive compound having three or more functional groups.

23. The manufacturing method according to claim 16, wherein: The coupling agent is a coupling agent having a nitrogen atom-containing group.

24. The manufacturing method according to claim 16, wherein: The coupling agent is a trifunctional or higher-functional reactive compound having a silicon atom.

25. The manufacturing method according to claim 16, wherein: The coupling agent is selected from the group consisting of compounds represented by formula (i) and (A) to (C), In formula (i), R is a hydrocarbon group having a valency of 2 or more, or a divalent or more organic group having at least one polar group selected from a polar group having oxygen, a polar group having sulfur, and a polar group having nitrogen; R 1 , R 4 is a hydrocarbon group having 1 to 10 carbon atoms, R 1 , R 4 They can be the same or different from each other; R 2 , R 5 is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R 2 , R 5 They can be the same or different from each other; R 3 is a hydrocarbon group having 1 to 10 carbon atoms, or a structure of the following formula (ii); R 1 , R 2 , R 3 It can be a ring structure formed by mutual bonding; R 3 In the case of a hydrocarbon group, it may be a cyclic structure bonded to R; in the case of the above cyclic structure, it may be a cyclic structure bonded to R 3 The bonded N and R are directly bonded; n is an integer greater than 1, and m is an integer greater than 0 or 1; In formula (ii), R 1 , R 2 and R of the formula (i) 1 , R 2 Similarly, R 1 , R 2 They can be the same or different from each other; 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, and 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; when there are plural numbers, R 1 ~R 4 Each is independent; 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, and 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, (m+n+l) represents an integer of 4 or more; when there are plural numbers, R 1 ~R 6 Each is independent; In formula (C), R 12 ~R 14 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, and 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, and R 21 represents an alkyl group or a trialkylsilyl group having 1 to 20 carbon atoms; m represents an integer from 1 to 3, and p represents 1 or 2; When there are multiple R 12 ~R 22 , m and p are independent of each other and can be the same or different; i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, and (i+j+k) is an integer from 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.

26. The manufacturing method according to claim 25, wherein: In the formula (A), m represents 2, and n represents 3; In the formula (B), n, m and l all represent 3; In the formula (C), A is represented by any one of the following formulas (II) to (V); 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 there are plural B 1 Each is independent; 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, a represents an integer of 1 to 10; when there are plural of each, B 2 and B 3 Each is independent; 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; when there are plural B 4 Each is independent; 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; when there are plural B 5 Each one is independent.

27. The manufacturing method according to claim 26, wherein: In the formula (C), A is represented by the formula (II) or the formula (III), k represents 0, and in the formula (II) and the formula (III), a represents an integer of 2 to 10. 28 . A conjugated diene polymer composition comprising 100 parts by mass of the conjugated diene polymer according to claim 1 , and 1 to 60 parts by mass of a rubber softener.

29. A rubber composition comprising a rubber component and 5.0 parts by mass or more and 150 parts by mass or less of a filler relative to 100 parts by mass of the rubber component, The rubber component contains 10 parts by mass or more of the conjugated diene polymer according to any one of claims 1 to 15 or the conjugated diene polymer composition according to claim 28, based on 100 parts by mass of the total amount of the rubber component.

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