Conjugated diene polymer, molded article, method for producing conjugated diene polymer, rubber composition, and tire

Abstract

This conjugated diene-based polymer satisfies the following <requirement (i)> to <requirement (iii)>. <Requirement (i)> The Mooney viscosity measured at 100ºC is 80-170. <Requirement (ii)> The Mooney stress-relaxation rate (MSR) measured at 100ºC is 0.30-0.80. <Requirement (iii)> A downward convex extreme value is shown in a branching degree distribution curve indicating the relationship between the absolute molecular weight and the branching degree (Bn), as measured by a measurement method using GPC with a viscosity detector and a light scattering method.

Description

[Technical Field]

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

[0002] In recent years, the demand for improved fuel efficiency in automobiles has increased, necessitating improvements to the rubber materials used in automobile tires, particularly in the tire treads that come into contact with the road surface. Due to the increasing demands for fuel efficiency regulations, there is a growing need for the use of resin in automobile components and thinner tires, all aimed at reducing the weight of automobiles.

[0003] A conjugated diene polymer is used as a component of the aforementioned rubber material. With regard to the aforementioned conjugated diene polymer, efforts are underway to increase its molecular weight from the viewpoint of improving fracture strength and abrasion resistance. However, high molecular weight conjugated diene polymers have a problem in that polymer particles easily peel off the surface of the bale itself, contaminating the area around the molding machine and the conveyor belt that transports the bale after molding with polymer particles, thus creating room for improvement in terms of the working environment.

[0004] One method to suppress the peeling of such high molecular weight conjugated diene polymers from the surface of the veil is to add process oil. For example, Patent Document 1 discloses a method for suppressing the peeling of polymer particles from the surface of a veil by adding process oil to a solution of a conjugated diene polymer to form an oil-expanded conjugated diene polymer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-131810 [Overview of the project] [Problems that the invention aims to solve]

[0006] Traditionally, conjugated diene polymers have been oil-expanded conjugated diene polymers with added process oil to improve bale moldability and processability after kneading. However, in recent years, there has been a desire to reduce the amount of process oil added to conjugated diene polymers as much as possible from the viewpoint of improving the degree of compounding freedom when producing rubber compositions.

[0007] However, in the case of the conjugated diene polymer veil disclosed in Patent Document 1, there is a problem that sufficient moldability may not be obtained when the amount of process oil added is reduced. For example, when increasing the molecular weight of a conjugated diene polymer to improve wear resistance, or setting a lower glass transition temperature of a conjugated diene polymer to improve low hysteresis loss, a problem arises in that if the amount of process oil added is small or the formulation does not contain process oil at all, the polymer particles tend to peel off easily from the surface of the veil.

[0008] Therefore, the present invention aims to provide a conjugated diene polymer that exhibits excellent bale-forming properties even in non-oil-based products without the addition of process oil. [Means for solving the problem]

[0009] As a result of diligent research and investigation to solve the above problems, the inventors of the present invention have found that a conjugated diene polymer having a predetermined Mooney viscosity and Mooney relaxation rate (MSR), and having a specific shape in the branching degree distribution curve measured by GPC-light scattering method with a viscosity detector, can solve the above problems, and have completed the present invention. In other words, the present invention is as follows.

[0010] [1] A conjugated diene polymer that satisfies the following conditions (i) to (iii). <Condition (i)> The Mooney viscosity measured at 100°C is between 80 and 170. <Condition (ii)> The Mooney relaxation ratio (MSR), measured at 100°C, is between 0.30 and 0.80. <Condition (iii)> GPC-light scattering measurement with a viscosity detector revealed that the branching degree distribution curve, which shows the relationship between absolute molecular weight and branching degree (Bn), has a downward-convex extreme value. [2] The glass transition temperature is -90°C to -40°C. The conjugated diene polymer described in [1] above satisfies the following conditions (I) to (III), with respect to the height of the peak top in the absolute molecular weight distribution curve measured by GPC-light scattering with a viscosity detector (however, if there are multiple peak tops in the absolute molecular weight distribution curve, the height of the peak top with the maximum absolute molecular weight) Hi, and Bn(high) being the degree of branching of the conjugated diene polymer at the highest absolute molecular weight Mw(high) among at least two absolute molecular weights when the height in the absolute molecular weight distribution curve is half the height of Hi (1 / 2Hi), and Bn(low) being the degree of branching of the conjugated diene polymer at the lowest absolute molecular weight Mw(low), and Bn(top) being the degree of branching of the conjugated diene polymer at the peak top of the absolute molecular weight distribution curve. <Condition (I)> (Bn(high))-(Bn(top))≧1.0 <Condition (II)> (Bn(low))-(Bn(top))≧0.5 <Condition (III)> (Bn(high)) / (Bn(low))=1.1~2.0 [3] The conjugated diene polymer according to [2], wherein the extreme value of the branching degree distribution curve lies in the absolute molecular weight between Mw(low) and Mw(high). [4] A conjugated diene polymer according to any one of [1] to [3] above, having a molecular weight distribution (PDI;MWD) of 1.4 to 3.5. [5] The conjugated diene polymer according to any one of [1] to [4], wherein the degree of branching at the extreme value in the branching degree distribution curve is 3.0 or more and 8.0 or less. [6] A conjugated diene polymer according to any one of [1] to [5] above, wherein the denaturation rate is 60% by mass or more. [7] The material has a fork-shaped portion [A] in which multiple conjugated diene polymer chains are bonded to one end of the main chain branched structure, and a single chain of another conjugated diene polymer is bonded to the other end of the main chain branched structure. The polymer includes a conjugated diene polymer having three or more branched star-shaped polymer structures [B] to which one or more fork-shaped portions [A] are bonded, A conjugated diene polymer according to any one of the above [1] to [6]. [8] A conjugated diene polymer having a fork-shaped portion [A] in which multiple conjugated diene polymer chains are bonded to one end of a main chain branch structure and a single chain of another conjugated diene polymer is bonded to the other end of the main chain branch structure, A conjugated diene polymer having a three-branched or more star-shaped polymer structure [B] to which one or more fork-shaped parts [A] are bonded, including, A conjugated diene polymer according to any one of [1] to [7] above. [9] 100 parts by mass of the conjugated diene polymer described in any one of [1] to [8] above, A softening agent component of less than 1 part by mass, A molded article containing the above.

[10] A method for producing a conjugated diene polymer according to any one of the above [1] to [8], A step of polymerizing at least a conjugated diene compound using an organolithium compound as a polymerization initiator, The process of adding a branching agent, A step of adding two or more coupling modifiers with different coupling numbers, A method for producing a conjugated diene polymer having the following characteristics.

[11] The two or more coupling modifiers mentioned above A coupling modifier comprising a coupling modifier having two or fewer alkoxysilyl groups, and a coupling modifier containing more than two alkoxysilyl groups, A method for producing the conjugated diene polymer described in

[10] above.

[12] 100 parts by mass of rubber component, The filler comprises 5.0 parts by mass or more and 150 parts by mass or less, The rubber composition comprises 10 parts by mass or more of the conjugated diene polymer described in any one of [1] to [8] above, per 100 parts by mass of the total amount of the rubber component.

[13] A tire containing the rubber composition described in

[12] above. [Effects of the Invention]

[0011] According to the present invention, even non-oil-based polymers without the addition of process oil can be provided that exhibit excellent bale-forming properties. [Brief explanation of the drawing]

[0012] [Figure 1] This is an illustrative diagram showing the relationship between the absolute molecular weight curve and the branching distribution obtained by GPC-light scattering measurement with a viscosity detector. [Modes for carrying out the invention]

[0013] The following describes in detail an embodiment for carrying out the present invention (hereinafter referred to as "this embodiment"). The following embodiments are illustrative examples for explaining the present invention, and the present invention is not limited to these embodiments. The present invention can be implemented by modifying it as appropriate within the scope of its gist.

[0014] [Conjugated diene polymers] The conjugated diene polymer of this embodiment satisfies the following conditions (i) to (iii). <Condition (i)> The Mooney viscosity measured at 100°C is between 80 and 170. <Condition (ii)> The Mooney relaxation ratio (MSR), measured at 100°C, is between 0.30 and 0.8. <Condition (iii)> GPC-light scattering measurement with a viscosity detector revealed that the branching degree distribution curve, which shows the relationship between absolute molecular weight and branching degree (Bn), has a downward-convex extreme value.

[0015] The conjugated diene polymer of this embodiment exhibits excellent bale-forming properties even in non-oil-applied products without the addition of process oil.

[0016] The conjugated diene polymer of this embodiment may be a homopolymer of a single conjugated diene compound, a polymer (i.e., copolymer) of different types of conjugated diene compounds, or a copolymer of a conjugated diene compound and a vinyl aromatic compound.

[0017] Examples of conjugated diene compounds include, but are not limited to, 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 viewpoint of effectively and reliably achieving the effects of this embodiment. These conjugated diene compounds may be used individually or in combination of two or more.

[0018] Furthermore, while not limited to the following, examples of vinyl aromatic compounds include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of effectively and reliably achieving the effects of this embodiment. These vinyl aromatic compounds may be used individually or in combination of two or more.

[0019] (Condition (i): Mooney viscosity of conjugated diene polymer) Mooney viscosity is an index that represents the overall characteristics of a conjugated diene polymer, including information on its molecular weight, molecular weight distribution, degree of branching, and softener content. Furthermore, the method for measuring Mooney viscosity is specified in ISO 289, and the measurement error due to instrumental differences is small, making it extremely effective in controlling the performance of conjugated diene polymers. The Mooney viscosity (hereinafter also simply referred to as "Mooney viscosity" or "ML") of the conjugated diene polymer of this embodiment, measured at 100°C, is 80 or higher. From the viewpoint of handling stability, fracture strength, and wear resistance when the crosslinking rubber composition containing the conjugated diene polymer of this embodiment is used in a tire, a viscosity of 90 or higher is preferred, and 100 or higher is more preferred. On the other hand, the upper limit is 170 or less, and from the viewpoint of moldability, productivity of molded articles of various shapes such as sheets or blocks, and rubber compositions containing the conjugated diene polymer of this embodiment, and processability of rubber compositions blended with fillers, etc., 160 or less is preferred, 150 or less is more preferred, and 145 or less is even more preferred.

[0020] Generally, the higher the Mooney viscosity of a conjugated diene polymer, the better the handling stability, fracture strength, and wear resistance when the conjugated diene polymer and its rubber composition are used in tires. On the other hand, the moldability of sheet-like or block-like molded articles or rubber compositions containing conjugated diene polymers tends to deteriorate. Generally, when the Mooney viscosity of a conjugated diene polymer is 80 or higher, the addition of process oil is required to form it into a bale. However, in the case of the conjugated diene polymer of this embodiment, as will be described later, by specifying that the branching degree distribution curve, which shows the relationship between absolute molecular weight and branching degree (Bn), has a downwardly convex extreme value, it is possible to form a bale even with a Mooney viscosity of 80 or higher, which would normally be difficult to form into a bale without the addition of process oil. Furthermore, by specifying a Mooney viscosity of 170 or lower, the peeling off of the conjugated diene polymer from the bale is suppressed, resulting in good bale formability.

[0021] The Mooney viscosity of conjugated diene polymers is determined by using a sample of the conjugated diene polymer, which has been formed into a plate shape by pressure pressing. The sample is set in a measuring device, preheated at 100°C for 1 minute, then the rotor is rotated at 2 rpm, and the torque is measured after 4 minutes. The measured value is then used to determine the Mooney viscosity (ML). (1+4) ) More specifically, it can be measured by the method described in the examples below. The Mooney viscosity of the conjugated diene polymer in this embodiment can be controlled to the above numerical range by adjusting the type, timing, and amount of branching agent and coupling modifier, as well as the molecular weight, molecular weight distribution, and degree of branching of the conjugated diene polymer.

[0022] (Condition (ii): Mooney relaxation rate of conjugated diene polymers) The Mooney relax rate (hereinafter also simply referred to as "Mooney relax rate" or "MSR") of the conjugated diene polymer of this embodiment, measured at 100°C, is 0.8 or less. From the viewpoint of processability of the rubber composition obtained by blending the conjugated diene polymer with fillers, etc., a value of 0.75 or less is preferred, and 0.72 or less is more preferred. On the other hand, the Mooney relax rate is 0.30 or more. From the viewpoint of handling stability and fracture strength when the conjugated diene polymer of this embodiment is used as a tire material, a value of 0.35 or more is preferred, 0.40 or more is more preferred, and 0.45 or more is even more preferred. Like Mooney viscosity, Mooney relaxation rate is influenced by the molecular weight, molecular weight distribution, degree of branching, and softener content of the conjugated diene polymer, and serves as an indicator of the overall characteristics of the conjugated diene polymer.

[0023] MSR can be measured using a Mooney viscometer as follows: The Mooney relaxation rate is calculated by first preheating the sample at 100°C for 1 minute, then rotating the rotor at 2 rpm, and measuring the torque after 4 minutes to determine the Mooney viscosity (ML). (1+4) After measuring the torque, the rotor rotation is immediately stopped, and the torque is recorded in Mooney units at 0.1-second intervals from 1.6 to 5 seconds after stopping. The slope of the line when torque and time (seconds) are plotted on a log-log scale is determined, and its absolute value is defined as the Mooney relaxation rate (MSR). More specifically, it can be measured by the method described in the examples below. The Mooney relaxation rate of the conjugated diene polymer in this embodiment can be controlled to the above numerical range by adjusting the type, timing, and amount of branching agent and coupling modifier, as well as the molecular weight, molecular weight distribution, and degree of branching of the conjugated diene polymer.

[0024] (Condition (iii): Shape of the branching distribution curve) In this embodiment, the conjugated diene polymer is designed to exhibit excellent processability while possessing excellent fracture strength and wear resistance, even as a non-oil-applied product without the addition of process oil. To achieve this, the degree of branching (Bn) measured by GPC-light scattering with a viscosity detector (hereinafter also simply referred to as "degree of branching (Bn)", "degree of branching", or "Bn") is plotted against the absolute molecular weight measured by GPC-light scattering with a viscosity detector (hereinafter also simply referred to as "absolute molecular weight") to determine the branching degree distribution curve, that is, the branching degree distribution curve showing the relationship between absolute molecular weight and branching degree (Bn), which has a shape with a downward-convex extreme value. The branching degree distribution curve serves as an indicator of the branching degree (Bn) of each molecular weight component in a conjugated diene polymer.

[0025] Generally, the degree of branching (Bn) is an indicator that describes the branched structure of a polymer. For example, in the case of a typical tetrabranched star polymer (a polymer in which four polymer chains (but without further side chains) are connected to the central part), two side chains are attached to the longest polymer backbone, and the degree of branching (Bn) is evaluated as 2.

[0026] In the case of a typical octave star polymer (a polymer in which eight polymer chains (but without further side chains) are connected to the central part), six side chains are attached to the longest polymer backbone, and the degree of branching (Bn) is evaluated as 6.

[0027] Here, "branching" refers to a structure formed by the bonding of one polymer chain to another. The "degree of branching (Bn)" is the number of polymer chains directly or indirectly bonded to the longest polymer backbone. In other words, it considers not only the side chains bonded to the longest polymer chain, but also the number of branches of those side chains if they are further branched. Therefore, if one polymer chain is bonded as a side chain to the longest polymer chain, and another polymer chain is further bonded to that side chain, the degree of branching is 2.

[0028] In this specification, the degree of branching (Bn) is calculated using the contraction factor (g') from the formula g' = 6Bn / {(Bn+1)(Bn+2)}. Here, the contraction factor (g') is defined as follows:

[0029] Generally, branched polymers tend to have smaller molecular sizes compared to linear polymers of the same absolute molecular weight. Here, "molecular size" refers to the volume substantially occupied by the molecule. The shrinkage factor (g') is a relative representation of the molecular size of a target polymer, and is an index of the ratio of the molecular size of the target polymer to the molecular size of a linear polymer of the same absolute molecular weight. In other words, the greater the degree of branching of a polymer, the smaller its relative size becomes, and therefore the shrinkage factor (g') tends to be smaller.

[0030] Here, since it is known that there is a correlation between the molecular size of a polymer and the ratio of its intrinsic viscosity, in this embodiment, the shrinkage factor (g') is defined by the ratio of intrinsic viscosities. That is, the shrinkage factor (g') is defined as the ratio ([η] / [η0]) of the intrinsic viscosity [η] of the target polymer to the intrinsic viscosity [η0] of a linear polymer having the same absolute molecular weight as the target polymer.

[0031] The intrinsic viscosity [η0] of a linear polymer is [η0] = 10 -3.498 M 0.711It is known that the following relationship is observed, where M is the absolute molecular weight. Therefore, the shrinkage factor (g') and branching degree (Bn) can be determined by measuring the absolute molecular weight and intrinsic viscosity of the target polymer using GPC-light scattering measurement with a viscosity detector. The calculated branching degree (Bn) accurately represents the number of polymer chains directly or indirectly bonded to the longest polymer backbone.

[0032] Here, "absolute molecular weight" refers to the molecular weight measured by light scattering. As mentioned above, branched polymers generally tend to have smaller molecular sizes compared to linear polymers with the same absolute molecular weight. Therefore, in the GPC measurement method, which determines molecular weight by sieving polymers by molecular size and comparing them to standard polystyrene samples, the molecular weight of branched polymers tends to be underestimated. On the other hand, light scattering measures molecular weight by directly observing the molecules. Therefore, light scattering can accurately measure molecular weight without being affected by the polymer structure or interactions with the column packing material. The absolute molecular weight can be measured by the method described in the examples below.

[0033] Furthermore, "intrinsic viscosity" ideally refers to the viscosity [η] calculated by the following equation (I). In formula (I), η1 represents the viscosity when the polymer in question is dissolved in a solvent at concentration c, and η2 represents the viscosity of the solvent. In this specification, the intrinsic viscosity is the value measured by the method described in the examples below.

[0034]

number

[0035] The conjugated diene polymer of this embodiment is assumed to have a branching degree distribution curve with a downward-convex extreme value, obtained by plotting the branching degree (Bn), measured by GPC-light scattering with a viscosity detector, against the absolute molecular weight. As a result, the conjugated diene polymer of this embodiment tends to have excellent bale-forming properties. Conventionally, a known method for producing branched polymers involves anionic polymerization of a conjugated diene polymer and then reacting the polymerization termination ends with a coupling modifier having multiple functional groups to branch the polymer. In this case, the low molecular weight components are linear polymer chains that are not coupled, and the branching degree curve is inflected at the number of branches corresponding to the number of functional groups in the coupling modifier. The coupled components have an increased number of branches and thus a higher molecular weight. In other words, the graph shows that the number of branches increases with molecular weight, and the branching degree distribution curve does not have an extremum. In contrast, the conjugated diene polymer of this embodiment exhibits an extreme value in its branching degree distribution curve, which is convex downwards. This indicates that the low molecular weight polymer is branched, and the increase in the number of branches on the high molecular weight side of the extreme value corresponds to the coupling of components at the polymerization termination end. When such a branching degree distribution is observed, the following reasons may be cited as factors that improve the veil-forming properties of the conjugated diene polymer, but are not limited to the reasons listed below.

[0036] Generally, the abrasion resistance and fracture strength of polymers tend to improve as the absolute molecular weight of the polymer increases. However, when the absolute molecular weight of a low-branching polymer is increased, polymer particles tend to peel off the surface of the veil more easily, worsening the veil's moldability. In addition, the viscosity during vulcanization increases significantly, and the processability during vulcanization tends to deteriorate significantly. Therefore, even if many functional groups are introduced into a low-branching polymer to improve its affinity and / or reactivity with silica used as a filler, the silica cannot be sufficiently dispersed in the polymer during the kneading process. As a result, low-branching polymers have limitations in terms of processability, which restricts the design freedom of their molecular weight.

[0037] On the other hand, the conjugated diene polymer of this embodiment is characterized by having a branching degree distribution curve with a downwardly convex extreme value. This downwardly convex extreme value of the branching degree distribution curve is formed by keeping the branching degree low near the peak top of the molecular weight distribution while increasing the branching degree on both the low molecular weight and high molecular weight sides. This improves bale moldability. Since the low molecular weight components also have a branched structure, the increase in viscosity during vulcanization that occurs with increasing absolute molecular weight can be suppressed. Conjugated diene polymers with a branching degree distribution curve having a downward-convex extreme are obtained by forming a mixture of polymers composed of components with different degrees of branching, with respect to maintaining an appropriate balance between branching structure and viscosity. Specifically, they can be obtained by adjusting the type and amount of branching agent described later, or by using two or more coupling modifiers described later and adjusting their types and various amounts. This makes it possible to improve the wear resistance, fuel efficiency, and fracture characteristics of vulcanized products without impairing the bale moldability of the conjugated diene polymer or the processability of the rubber composition.

[0038] (Glass transition temperature of conjugated diene polymers) The conjugated diene polymer of this embodiment preferably has a glass transition temperature (hereinafter also referred to as "Tg") of -90°C or higher, more preferably -78°C or higher, and even more preferably -65°C or higher. A glass transition temperature of -90°C or higher tends to result in excellent processability during vulcanization. Furthermore, the glass transition temperature of the conjugated diene polymer of this embodiment is preferably -10°C or lower, more preferably -20°C or lower, even more preferably -40°C or lower, even more preferably -45°C or lower, even more preferably -50°C or lower, and particularly preferably -55°C or lower. A glass transition temperature of -10°C or lower tends to result in excellent fracture strength, abrasion resistance, and low hysteresis loss properties of the vulcanized product of the conjugated diene polymer. The glass transition temperature may be within a range arbitrarily determined by combining the above upper and lower limits. The glass transition temperature of conjugated diene polymers can be measured according to ISO 22768:2017. More specifically, differential scanning calorimetry (DSC) measurements are performed while increasing the temperature within a predetermined range to record the DSC curve, and the peak top (inflection point) of the DSC differential curve is defined as the glass transition temperature. Specifically, it can be measured by the method described in the examples below.

[0039] The microstructure of a conjugated diene polymer (amount of bonded vinyl aromatic monomer units, amount of bonded conjugated diene monomer units, and ratio of vinyl bonds in bonded conjugated diene monomer units) affects the glass transition temperature of the conjugated diene polymer. Therefore, there is a preferred range for the amount of bonded vinyl aromatic monomer units and vinyl bonds from the viewpoint of controlling the glass transition temperature. In the microstructure of a conjugated diene polymer, the amount of bonded vinyl aromatic monomer units is not particularly limited, but it is preferably 1% by mass or more and 40% by mass or less relative to the entire conjugated diene polymer, more preferably 1% by mass or more and 36% by mass or less, even more preferably 1% by mass or more and 30% by mass or less, even more preferably 2% by mass or more and 29% by mass or less, even more preferably 3% by mass or more and 28% by mass or less, and particularly preferably 5% by mass or more and 27% by mass or less. When the amount of bonded vinyl aromatic monomer units is within the above range, the vulcanized product of the conjugated diene polymer tends to have even better fracture strength, abrasion resistance, and low hysteresis loss properties. Furthermore, an increase in the amount of bonded vinyl aromatic monomer units tends to increase the Tg of the conjugated diene polymer, while a decrease in the amount tends to decrease the Tg. In this specification, "amount of bonded vinyl aromatic monomer units" means the content of the portion derived from the aromatic vinyl compound used as a monomer.

[0040] The amount of bonded conjugated diene monomer units in the microstructure of a conjugated diene polymer is not particularly limited, but is preferably 60% to 99% by mass relative to the entire conjugated diene polymer, more preferably 64% to 99% by mass, even more preferably 70% to 99% by mass, even more preferably 71% to 98% by mass, even more preferably 72% to 97% by mass, and particularly preferably 73% to 95% by mass. When the amount of bonded conjugated diene monomer units is within the above range, the vulcanized product of the conjugated diene polymer tends to have even better fracture strength, abrasion resistance, and low hysteresis loss properties. In this specification, "amount of bonded conjugated diene monomer units" means the content of the portion derived from the conjugated diene compound used as a monomer.

[0041] In the microstructure of a conjugated diene polymer, the amount of vinyl bonds in the conjugated conjugated diene monomer unit (hereinafter also simply referred to as "vinyl bond amount") is not particularly limited, but is preferably 11 mol% to 60 mol%, more preferably 11 mol% to 40 mol%, even more preferably 12 mol% to 35 mol%, even more preferably 13 mol% to 34 mol%, even more preferably 14 mol% to 33 mol%, and particularly preferably 15 mol% to 30 mol%. When the vinyl bond amount is within the above range, the conjugated diene polymer tends to have improved fracture strength and abrasion resistance because the linearity of the structure of the conjugated diene portion increases and the entanglement between polymer chains strengthens. Furthermore, when the vinyl bond amount is within the above range, the vulcanized product tends to have improved low hysteresis loss properties. Furthermore, an increase in the amount of vinyl bonds leads to a higher Tg, and a decrease in the amount of vinyl bonds leads to a lower Tg. In this specification, "amount of vinyl bonds in a conjugated diene monomer unit" means the proportion of the portion having vinyl bonds among the portion derived from the conjugated diene compound used as a monomer (hereinafter referred to as "conjugated conjugated diene monomer unit").

[0042] (Relationship between absolute molecular weight curve and degree of polymer branching) As described above, the conjugated diene polymer of this embodiment preferably has a shape in which the branching degree distribution curve has a downwardly convex extreme value near the peak top of the molecular weight distribution curve. In this embodiment, the conjugated diene polymer preferably satisfies the following conditions (I) to (III), when the height of the peak top in the absolute molecular weight distribution curve measured by GPC-light scattering with a viscosity detector is defined as Hi (however, if there are multiple peak tops in the absolute molecular weight distribution curve, the height of the peak top with the maximum absolute molecular weight): Hi is used as a reference, and when the height in the absolute molecular weight distribution curve is half the height of Hi (1 / 2Hi), the branching degree of the conjugated diene polymer at the highest absolute molecular weight Mw(high) among at least two absolute molecular weights is defined as Bn(high), the branching degree of the conjugated diene polymer at the lowest absolute molecular weight Mw(low) is defined as Bn(low), and the branching degree of the conjugated diene polymer at the peak top of the absolute molecular weight distribution curve is defined as Bn(top). <Condition (I)> (Bn(high))-(Bn(top))≧1.0 <Condition (II)> (Bn(low))-(Bn(top))≧0.5 <Condition (III)> (Bn(high)) / (Bn(low))=1.1~2.0

[0043] Furthermore, when the absolute molecular weight distribution curve is distinguished into high molecular weight components and low molecular weight components based on its peak top, the degree of branching of the conjugated diene polymer at absolute molecular weight Mw(high) (Bn(high)) and the degree of branching of the conjugated diene polymer at absolute molecular weight Mw(low) (Bn(low)) correspond to the average degree of branching of the high molecular weight components and low molecular weight components, respectively. Satisfying the conditions (I)) above (Bn(high))-(Bn(top))≧1.0 and (II) above (Bn(low))-(Bn(top))≧0.5 means that the entire polymer chain has a high degree of branching in both the low molecular weight and high molecular weight regions, and the peak-top region of the absolute molecular weight curve has a low degree of branching. From the viewpoint of the bale-forming properties and processability during vulcanization of the conjugated diene polymer, the (Bn(high))-(Bn(top)) in <Condition (I)> is preferably 1.0 or higher, more preferably 1.5 or higher, even more preferably 1.9 or higher, and even more preferably 2.4 or higher. Furthermore, the (Bn(low))-(Bn(top)) in <Condition (II)> is preferably 0.5 or higher, more preferably 0.6 or higher, even more preferably 0.7 or higher, and even more preferably 0.9 or higher. In the above-mentioned condition (III), (Bn(high)) / (Bn(low)) is an index indicating the position of the average branching degree of the high molecular weight component relative to the average branching degree of the low molecular weight component. From the viewpoint of the bale-forming properties and processability during vulcanization of the conjugated diene polymer, a value of 1.1 or higher is preferred, 1.2 or higher is more preferred, 1.25 or higher is even more preferred, and 1.3 or higher is still more preferred. Furthermore, a value of 2.0 or lower is preferred, 1.8 or lower is more preferred, 1.7 or lower is even more preferred, 1.6 or lower is still still more preferred, and 1.5 or lower is still still more preferred.

[0044] In order for the conjugated diene polymer of this embodiment to satisfy the above-mentioned conditions (I) to (III) in terms of the relationship between the absolute molecular weight distribution curve and the degree of branching, it is effective to adjust the type and amount of branching agent, the type and amount of coupling modifier in the method for producing the conjugated diene polymer. Specifically, as will be described later, it is effective to use a combination of a branching agent that can constitute the main chain branched structure and two or more coupling modifiers with different coupling numbers.

[0045] As described above, the conjugated diene polymer of this embodiment has a shape with a downward-convex extremum in the branching degree distribution curve, which shows the relationship between absolute molecular weight and branching degree (Bn). That is, the branching degree distribution curve has a downward-convex extremum near the peak of the absolute molecular weight distribution curve. Here, the area near the peak of the molecular weight distribution curve refers to the range in the molecular weight distribution curve where the absolute molecular weight is greater than or equal to Mw(low) and less than or equal to Mw(high).

[0046] Figure 1 is an illustrative diagram showing an example of the relationship between the absolute molecular weight distribution curve and the branching degree distribution curve obtained by GPC-light scattering measurement with a viscosity detector. In Figure 1, the dashed line B and the solid line C are branching degree distribution curves showing the relationship between the absolute molecular weight and the degree of branching of conjugated diene polymers, and the solid line A is the absolute molecular weight distribution curve. Generally, in the case of a simple star-shaped conjugated diene polymer obtained by reacting one end of the active end of a conjugated diene polymer with a coupling modifier, the degree of branching tends to increase with increasing molecular weight, as shown by the dashed line B in Figure 1. On the other hand, the conjugated diene polymer of this embodiment has a high degree of branching in both the low molecular weight and high molecular weight regions, as shown by solid line C, and has a shape with downward-convex extreme values. The extreme values ​​are preferably located near the peak top of the absolute molecular weight curve (solid line A), as shown by solid line C. In other words, the conjugated diene polymer of this embodiment not only has a high degree of branching in the high molecular weight component, but also has a branched structure introduced into the low molecular weight component, which also has a high degree of branching. As a result, it has excellent bale moldability even without oil application. Low molecular weight components are generally less likely to become powder rubber and tend to be easier to mold into bales compared to high molecular weight components, but by further introducing a branched structure into the low molecular weight component, the bale moldability of the conjugated diene polymer is further improved.

[0047] Furthermore, in conjugated diene polymers containing vinyl aromatic monomer units, setting a low amount of vinyl bonds in the conjugated diene monomer units or a low content of vinyl aromatic monomer units tends to lower the Tg of the conjugated diene polymer, resulting in improved wear resistance and low hysteresis when used as a vulcanized product. Therefore, there is a need to design polymers with such a structure. On the other hand, setting a low amount of vinyl bonds or a low content of vinyl aromatic monomer units has a negative impact on moldability when forming block-shaped bale molds and on processability when forming vulcanized products. In particular, for non-oil-applied products that are difficult to form into bale molds, the reduction of vinyl bonds or vinyl aromatic monomer unit content tends to be practically limited. The inventors have found that, by identifying the branching degree distribution curve as described above, conjugated diene polymers can be non-oil-expanded while maintaining good bale moldability. As a result, the constraints on reducing the amount of vinyl bonds and vinyl aromatic monomer units in the microstructure design of non-oil-expanded products are alleviated, making it possible to set a lower glass transition temperature.

[0048] (Mooney viscosity curve) The conjugated diene polymer of this embodiment preferably has two or more extreme values ​​in the Mooney viscosity curve (hereinafter also referred to as the "ML curve") measured at 100°C. The Mooney viscosity curve (hereinafter also referred to as the "ML curve") is generally obtained by plotting the Mooney viscosity value against the measurement time. For example, in the case of polymers with a linear structure, the entanglement between polymer chains gradually unravels over time during Mooney viscosity measurement, resulting in a Mooney viscosity curve without extreme values. Furthermore, when the molecular weight is increased in a linear molecular structure, the entanglement between polymer chains does not unravel within the measurement time, and the Mooney viscosity curve saturates at a constant Mooney viscosity value, and no decay behavior of Mooney viscosity is observed. On the other hand, in the case of polymers with a branched structure, the entanglement of molecules tends to decrease compared to linear polymers of the same molecular weight. Therefore, even polymers with high molecular weight structures tend to have a Mooney viscosity curve with an upward-convex extreme value, as the entanglement of polymer chains unravels within the measurement time. Furthermore, as mentioned above, Mooney viscosity is an indicator that shows the overall characteristics of a conjugated diene polymer, including information on its molecular weight, molecular weight distribution, degree of branching, and softener content. In addition, the method for measuring Mooney viscosity is specified in ISO 289, and the measurement error due to instrumental differences is small, making it extremely effective in controlling the performance of conjugated diene polymers.

[0049] The conjugated diene polymer of the present embodiment has a glass transition temperature within a specific numerical range from the viewpoints of the productivity of the conjugated diene polymer, the handling stability when the rubber composition is vulcanized, and the breaking strength, and it is preferable that there are two or more extreme values in the Mooney viscosity curve. More preferably, it is a conjugated diene polymer in which the first extreme value is convex downward and the second extreme value is convex upward. The two extreme values of the Mooney viscosity curve are derived from the fact that the branching degree distribution curve has a downward convex shape, and each extreme value corresponds to the relaxation of the low molecular weight component containing the branched structure and the high molecular weight component containing the branched structure, that is, the degree of entanglement becomes smaller.

[0050] (Average molecular weight and molecular weight distribution) The weight average molecular weight of the conjugated diene polymer of the present embodiment, measured by the GPC measurement method, is preferably 35×10 4 or more, more preferably 40×10 4 or more, still more preferably 50×10 4 or more, even more preferably 55×10 4 or more, and even more preferably 60×10 4 or more. When the weight average molecular weight measured by the GPC measurement method is 35×10 4 or more, the vulcanizate thereof is further excellent in low hysteresis loss property. Also, the above weight average molecular weight is preferably 250×10 4 or less, more preferably 200×10 4 or less, still more preferably 150×10 4 or less, and even more preferably 100×10 4 or less. When the weight average molecular weight is 250×10 4 or less, the vulcanizate is further excellent in the dispersibility of the filler and tends to obtain practically sufficient breaking properties. The weight average molecular weight may be within a range arbitrarily combining the above upper and lower limit values. The weight average molecular weight of the conjugated diene polymer can be measured by the method described in the examples below. <00​​The conjugated diene polymer of this embodiment preferably has a number-average molecular weight of 20 × 10 as measured by GPC. 4 That is all, more preferably 25 × 10 4 The above, and more preferably 30 × 10 4 That concludes the explanation. The number average molecular weight is 35 × 10 4 The number average molecular weight measured by the GPC method is 20 × 10 4 When the above is true, the processability during vulcanization is further improved, and the vulcanized product tends to have even better low hysteresis loss properties. Furthermore, the number average molecular weight is preferably 100 × 10 4 The following, more preferably 90 × 10 4 The following, and more preferably 80 × 10 4 The following, and more preferably 70 × 10 4 The following applies: The number-average molecular weight is 20 × 10 4 When these conditions are met, the dispersibility of the filler in the vulcanized product is even better, and the fracture properties tend to be sufficiently effective for practical use. The number-average molecular weight may be within a range that can be arbitrarily combined from the above upper and lower limits. The number-average molecular weight of conjugated diene polymers can be measured by the method described in the examples below.

[0052] In the conjugated diene polymer of this embodiment, the ratio of the weight-average molecular weight (Mw) measured by the GPC method to the number-average molecular weight (Mn) measured by the GPC method (Mw / Mn) (molecular weight distribution) is preferably 1.4 or higher, more preferably 1.5 or higher, even more preferably 1.5 or higher, and even more preferably 1.6 or higher, from the viewpoint of processability during vulcanization, wear resistance of the vulcanized product, and fracture strength. The upper limit of the molecular weight distribution is not particularly limited, but is generally preferably 3.5 or lower, more preferably 2.5 or lower, even more preferably 2.0 or lower, and even more preferably 2.0 or lower. The molecular weight distribution of conjugated diene polymers can be controlled to the above numerical range by adjusting polymerization conditions such as the type and amount of monomers, polymerization initiators, and polar compounds added, polymerization time, polymerization temperature, and the amount and type of coupling modifiers added, as well as their combinations if two or more are used.

[0053] (Branching degree at the extreme value of the branching degree distribution curve) In the branching degree distribution curve of the conjugated diene polymer of this embodiment, as described above, it is preferable to have a shape in which the branching degree distribution curve has a downwardly convex extreme value near the peak top of the molecular weight distribution curve. The degree of branching of the conjugated diene polymer at the downward-convex extreme value of the branching degree distribution curve is preferably 3.0 to 8.0, more preferably 3.0 to 7.0, even more preferably 3.0 to 6.0, and even more preferably 3.0 to 5.0, from the viewpoint of processability when vulcanizing the conjugated diene polymer of this embodiment, wear resistance of the vulcanized product, and fracture strength. The degree of branching of a conjugated diene polymer at the downward-convex extreme value of the branching degree distribution curve can be controlled by the type and amount of branching agent, as described later. For example, if the branching degree at the extreme value is less than 3.0, it can be controlled to 3.0 or higher by increasing the amount of branching agent or by using a branching agent with a large number of branches (such as diphenylethylene). Conversely, if it exceeds 8.0, it can be controlled to 8.0 or lower by reducing the amount of branching agent or by changing to a branching agent with a smaller expected number of branches.

[0054] (modified group) The conjugated diene polymer of this embodiment preferably has a modified group. A "modified group" refers to a functional group that has affinity or bonding reactivity with the filler, and examples include functional groups containing a nitrogen atom. The conjugated diene polymer of this embodiment, by having such a modifying group, exhibits improved interaction with the filler, and therefore, when a composition of the conjugated diene polymer containing the filler is formed, the fracture strength of the composition is further improved. From a similar viewpoint, the conjugated diene polymer of this embodiment preferably has a modifying group having a nitrogen atom, and more preferably has a modifying group having both a nitrogen atom and a silicon atom. It is not necessary for a single modifying group or coupling modifying agent to contain both a nitrogen atom and a silicon atom; a modifying group containing only one of them, or a coupling modifying agent having a modifying group, may be combined so that the polymer contains both nitrogen and silicon.

[0055] (Degeneration rate) In this specification, "modification rate" refers to the percentage by mass of a modified conjugated diene polymer component having a specific functional group in its polymer molecule that has affinity or bonding reactivity to a filler, relative to the total amount of the conjugated diene polymer mixture, when a mixture of a modified conjugated diene polymer and an unmodified conjugated diene polymer is obtained by modifying a conjugated diene polymer with a coupling modifying agent. Therefore, if the specific functional group contains a nitrogen atom, it refers to the mass ratio of the conjugated diene polymer containing the nitrogen atom to the total amount of the conjugated diene polymer mixture. In this specification, unless otherwise specified, or unless clearly distinguished, such as being listed in parallel as "conjugated diene polymer or modified conjugated diene polymer," "conjugated diene polymer" encompasses both unmodified conjugated diene polymers and modified conjugated diene polymers. In cases where "conjugated diene polymer or modified conjugated diene polymer" is listed in parallel, "conjugated diene polymer" refers to an unmodified conjugated diene polymer.

[0056] For example, in a conjugated diene polymer including a modified conjugated diene polymer obtained by reacting a nitrogen atom-containing modifying agent at the terminal end, the modification rate is the mass ratio of the modified conjugated diene polymer having a nitrogen atom-containing functional group due to the nitrogen atom-containing modifying agent to the total amount of the conjugated diene polymer.

[0057] The conjugated diene polymer of this embodiment is preferably modified with a functional group containing at least a portion of nitrogen atoms, and more preferably with a functional group containing both nitrogen and silicon atoms. Such a modified conjugated diene polymer exhibits superior processability when compounded with fillers and the like to form a rubber composition, and tends to exhibit superior abrasion resistance, fracture strength, and low hysteresis loss when the rubber composition is vulcanized. It should be noted that, as described above, it is not necessary for a single modifying group or coupling modifying agent to contain both nitrogen and silicon atoms; a modifying group or coupling modifying agent containing only one of these atoms may be combined so that the final modified conjugated diene polymer contains both nitrogen and silicon.

[0058] From the viewpoint of improving the low hysteresis loss properties in the vulcanized product, the modification rate of the conjugated diene polymer in this embodiment is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, even more preferably 75% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the conjugated diene polymer. The upper limit of the modification rate is not particularly limited, but may be 100% by mass, 98% by mass or less, 95% by mass or less, or 90% by mass or less. Furthermore, when comparing modified conjugated diene polymers with the same glass transition temperature, a higher modification rate tends to result in superior low hysteresis loss properties.

[0059] In the conjugated diene polymer of this embodiment, the denaturation rate can be measured by chromatography that can separate the functional group-containing denatured component from the undenatured component. One such chromatography method is to use a gel permeation chromatography column packed with a polar substance such as silica that adsorbs specific functional groups, and quantify the unadsorbed component using an internal standard for comparison (column adsorption GPC method).

[0060] More specifically, the denaturation rate can be obtained by calculating the amount adsorbed onto the silica column from the difference between the chromatogram obtained by measuring the sample solution containing the sample and low molecular weight internal standard polystyrene on a polystyrene gel column and the chromatogram obtained by measuring the same sample solution on a silica column. Specifically, the denaturation rate can be measured by the method described in the examples below.

[0061] In the conjugated diene polymer of this embodiment, the modification rate can be controlled to the above-mentioned numerical range by adjusting the amount of coupling modifier added and the reaction method between the conjugated diene compound and the modifier. For example, one can combine a polymerization method using an organolithium compound having at least one nitrogen atom in the molecule as a polymerization initiator, a copolymerization method using a monomer having at least one nitrogen atom in the molecule, and a structural formula modifier as described later.

[0062] (Structure of conjugated diene polymers) The conjugated diene polymer of this embodiment is a collection of polymers with substantially different shapes. Because it is a collection of polymers with different branching numbers and molecular weights, the branching degree distribution curve exhibits a downward convex shape. In a preferred embodiment, components on the low molecular weight side of the extreme value have a fork-like structure in which the polymer chain branches into multiple polymer chains midway, while components on the high molecular weight side of the extreme value have a structure in which this fork-like structure forms multiple star-shaped branches. The branched portion of the fork-shaped structure is called the "main chain branched structure portion," and it is preferable that it is an atomic group containing alkoxysilyl groups or halosilyl group heteroatoms, as described later. A fork-shaped portion [A] is formed when multiple conjugated diene polymer chains are bonded to one end of the main chain branched structure portion, and a single chain of another conjugated diene polymer is bonded to the other end. The specific manufacturing method is as follows: A branching agent having a functional group that reacts with the polymerization active ends of multiple polymer chains and a portion that continues polymerization is reacted with the branching agent, and polymerization continues as the branching agent binds to multiple conjugated diene polymer chains, thereby forming the "main chain branched structure." A single chain of the conjugated diene polymer that has continued polymerization from the branching agent is further bonded with one or more coupling modifiers that form a star-shaped branched structure of three or more branches, thereby forming a star-shaped branched structure (star polymer structure [B]). A portion of the fork-shaped portion [A] is coupled to form a star polymer structure [B] of three or more branches, while the remaining portion that is not coupled remains uncoupled as a polymer having the fork-shaped portion [A], resulting in an overall molecular weight distribution curve that is convex downwards.

[0063] The conjugated diene polymer of this embodiment preferably contains a conjugated diene polymer having the uncoupled fork-shaped portion [A] and not having a star-shaped polymer structure portion [B], and a conjugated diene polymer having a star-shaped polymer structure portion [B] in which the fork-shaped portion [A] is coupled. The ratio of these may be arbitrary, but it is preferable that the mass ratio of the conjugated diene polymer having only the uncoupled fork-shaped portion [A] is larger than that of the conjugated diene polymer having the star-shaped polymer structure portion [B].

[0064] In this specification, "main chain branched structure" refers to a structure in which polymer chains form branching points, and polymer chains (arms) extend from these branching points. Typically, branching points composed of portions derived from vinyl monomers containing alkoxysilyl groups or halosilyl groups have two or more branching points, preferably three or more, and more preferably four or more.

[0065] In this specification, a "star-shaped polymer structure" refers to a structure in which three polymer chains (arms) are linked upward from a single central branching point. It is preferable that the branching originating from the star-shaped polymer structure has three or more branches, more preferably four or more branches, even more preferably six or more branches, and even more preferably eight or more branches.

[0066] Furthermore, the central branching point referred to here is an aggregate (group of atoms) having substituents containing atoms derived from the coupling modifier or nitrogen atoms derived from the modifier, and does not mean a single atom. For example, an aggregate having an alkoxysilyl group flanking an amino group with 1 to 5 carbon atoms, preferably 2 to 3 carbon atoms, is a typical central branching point.

[0067] <Main chain branching structure and branching agents> In this specification, vinyl monomers containing alkoxysilyl groups or halosilyl groups used to construct the "main chain branched structure" are referred to as "branching agents." As a branching agent, it is preferable to use a vinyl monomer containing an alkoxysilyl group or a halosilyl group represented by the following formula (1) or (2). That is, the "main chain branched structure" is preferably composed of atomic groups derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group represented by the following formula (1) or (2).

[0068] [ka]

[0069] [ka]

[0070] In formula (1), R 1 This represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have 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 may have a branched structure in part. 1 ~R 3 They are all independent of each other. X 1 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m + n + l) represents 3.

[0071] In formula (2), R 4 ~R 7 Each of these independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. When multiple Rs exist 4 ~R 7 They are all independent of each other. X 2 ~X 3 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m+n+l) represents 3. a represents an integer between 0 and 3, b represents an integer between 0 and 2, and c represents an integer between 0 and 3. (a + b + c) represents the integer 3.

[0072] The conjugated diene polymer of this embodiment is R of formula (1) described above. 1 Preferably, the monomer unit is a hydrogen atom and m=0, and is based on the compound represented by formula (1). This increases the overall number of branches in the conjugated diene copolymer, resulting in improved wear resistance and processability.

[0073] Furthermore, the conjugated diene polymer of this embodiment is preferably a modified conjugated diene polymer having monomer units based on the compound represented by formula (2), where m=0 and b=0 in formula (2). This results in improved wear resistance and machinability.

[0074] Furthermore, the conjugated diene polymer of this embodiment is R of formula (1) described above. 1 Preferably, the monomer unit is a hydrogen atom, has m=0, and has l=0, and is based on a compound represented by formula (1). This improves the overall branching degree of the conjugated diene copolymer, resulting in improved wear resistance and processability.

[0075] Furthermore, the conjugated diene polymer of this embodiment is preferably a conjugated diene polymer having monomer units based on the compound represented by formula (2), where m=0, l=0, a=0, and b=0. This results in improved wear resistance and machinability.

[0076] Furthermore, the conjugated diene polymer of this embodiment is more preferably R in formula (1) above. 1 It is preferable that the polymer is a conjugated diene polymer having monomer units based on the compound represented by formula (1) above, where l=0 and n=3, where l is a hydrogen atom. This improves the rate of deformation and branching, resulting in improved fuel efficiency, wear resistance, and machinability.

[0077] <A conjugated diene polymer with a long, fork-like stalk> A structure in which the single-chain side of the fork-shaped portion [A] is longer is referred to as a fork-shaped structure with a long stalk. This structure can also be formed by the continued polymerization of the single chain, but when producing a conjugated diene polymer having the long-stalked fork-shaped structure simultaneously with a polymer having a three-branched or more star-shaped polymer structure [B] to which one or more fork-shaped portions [A] are bonded, it is appropriate to use a method in which the single chain of the fork-shaped portion [A] is reacted with a bibranched coupling modifier. Conjugated diene polymers with long, fork-like stalks are constructed by building a comb-like structural moiety derived from the main chain branching structure, followed by continued polymerization to increase the molecular weight. After building the comb-like structural moiety derived from the main chain branching structure and continuing polymerization to increase the molecular weight, it is preferable to modify the polymer with a coupling modifier of two or fewer functionalities. More preferably, a bifunctional coupling modifier is used to further increase the molecular weight of the stalk portion.

[0078] A fork-shaped conjugated diene polymer with a long stalk, where the single-chain side of the fork-shaped portion [A] is longer, preferably contains a structure in the long stalk portion that has a nitrogen atom-containing group represented by any of the following general formulas (3), (4-1), or (4-2).

[0079] [ka]

[0080] In formula (3), P 1 , P 2 The polymer chain is a fork-shaped portion [A] having a main chain branching structure on one end, and a linear polymer chain without a branching structure on the other end. R 8 R is a hydrocarbon group or hydrocarbyl group having 1 to 20 carbon atoms. 10 is a hydrocarbon group having 1 to 20 carbon atoms, which may be substituted with an organic group containing S, O, or N and lacking active hydrogen, and may have an unsaturated bond, and may be the same or different. R 11 , R 12R is an aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may have unsaturated bonds and may be the same or different. 13 is a hydrocarbon group having 1 to 20 carbon atoms, which contains Si, O, or N and may be substituted with an organic group that does not have active hydrogen, and may contain unsaturated bonds.

[0081] [ka]

[0082] [ka]

[0083] In equations (4-1) and (4-2) above, P 1 , P 2 The polymer chain is a fork-shaped portion [A] having a main chain branching structure on one end, and a linear polymer chain without a branching structure on the other end. R 14 , R 15 R is a hydrocarbon group or hydrocarbyl group having 1 to 20 carbon atoms. 16 is a hydrocarbon group having 1 to 20 carbon atoms, which may have unsaturated bonds, may be substituted with an organic group containing O or N that does not have active hydrogen, and may be the same or different. R 17 , R 18 is a hydrocarbon group having 1 to 20 carbon atoms, which contains Si, O, or N and may be substituted with an organic group that does not have active hydrogen, and may contain unsaturated bonds.

[0084] <Conjugated diene polymer having a star-shaped polymer structure [B]> A conjugated diene polymer having a star-shaped polymer structure [B] is a conjugated diene polymer having a star-shaped polymer structure with three or more branches, constructed by first building a comb-shaped structural portion derived from the main chain branching structure, then continuing polymerization to increase the molecular weight, and finally modifying it with a coupling modifier with three or more functions. Such a conjugated diene polymer has a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group in at least one branched chain of the star-shaped structure. Regarding a method for obtaining a conjugated diene polymer having a further main chain branching structure in the portion derived from the vinyl monomer containing an alkoxysilyl group or a halosilyl group, the "star-shaped polymer structure" can be formed by adjusting the number of functional groups of the modifier and the amount of modifier added, and the "main chain branching structure" can be controlled by adjusting the number of functional groups of the branching agent, the amount of branching agent added, and the timing of the branching agent addition.

[0085] <Conjugated diene polymer having a star-shaped polymer structure [B]> The conjugated diene polymer of this embodiment preferably contains a structure in its star-shaped branched structure that has a nitrogen atom-containing group represented by any of the following general formulas (5-1) to (5-4), (7-1) to (7-2), (8), or (9-1) to (9-2).

[0086] [ka]

[0087] [ka]

[0088] [ka]

[0089] [ka]

[0090] In formulas (5-1) to (5-4) above, R is a divalent or greater hydrocarbon group, or a divalent or greater organic group having at least one polar group selected from oxygen-containing polar groups such as ethers, epoxys, and ketones, sulfur-containing polar groups such as thioethers and thioketones, and nitrogen-containing polar groups such as tertiary amino groups and imino groups.

[0091] The hydrocarbon group with two or more valent values ​​is a hydrocarbon group that may be saturated or unsaturated, linear, branched, or cyclic, and includes alkylene groups, alkenylene groups, phenylene groups, etc. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. Examples include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, p-phenylene, m-, p-xylene, bis(phenylene)-methane, etc.

[0092] In the above equations (5-1) to (5-4), R 24 , R 27 R is a hydrocarbon group having 1 to 10 carbon atoms. 24 , R 27 They may be the same or different from each other.

[0093] In the above equations (5-1) to (5-4), R 25 , R 28 R is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms. 25 , R 28 They may be the same or different from each other.

[0094] In the above equations (5-1) to (5-4), P 3 , P 4 This is a polymer chain, which is a fork-shaped portion [A] having a main chain branching structure, or a linear polymer chain without a branching structure.

[0095] In the above equations (5-1) to (5-4), R 26 This is a hydrocarbon group having 1 to 10 carbon atoms, or a structure of the following formulas (6-1) to (6-3).

[0096] [ka]

[0097] [ka]

[0098] [ka]

[0099] In the above equations (5-1) to (5-4), R 24 , R 25 , R 26 These may be interconnected ring structures.

[0100] Also, in the above equations (5-1) to (5-4), R 26 If R is a hydrocarbon group, it may be a cyclic structure bonded to R. In the case of the aforementioned cyclic structure, R 26 The N and R that are bonded together may be directly bonded to each other.

[0101] In equations (5-1) to (5-4) above, f is an integer greater than or equal to 1, and g is 0 or an integer greater than or equal to 1.

[0102] In the above equations (6-1) to (6-3), R 29 , R 30 These are the R values ​​in the above equations (5-1) to (5-4), respectively. 24 , R 25 It is defined similarly, and in the above equations (6-1) to (6-3), P 5 This is P in the above equations (5-1) to (5-4). 3 , P 4 It is defined similarly. R 29 , R 30 They may be identical or different from one another.

[0103] [Chemical formula]

[0104] [Chemical formula]

[0105] In the above formulas (7-1) to (7-2), P 6 , P 7 is a polymer chain, which is a fork-shaped part [A] having a main-chain branched structure or a linear polymer chain having no branched structure. P 6 , P 7 When a plurality of each of them are bonded (when h or i or j is an integer of 2 or more), P 6 , P 7 may be the same as or different from each other. R 33 , R 34 each independently represents an alkyl group or a hydrocarbyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R[[ID=%]] 35 represents an alkylene group having 1 to 10 carbon atoms, and R 36 represents an alkylene group having 1 to 20 carbon atoms. h represents an integer of 1 to 3, i represents an integer of 1 to 3, j represents an integer of 1 or 2, and (h + i) and (h + j) represent an integer of 3 or more.

[0106] [Chemical formula]

[0107] In the above formula (8), P 8 , P<000 9 , P 10 is a polymer chain, which is a fork-shaped part [A] having a main-chain branched structure or a linear polymer chain having no branched structure. P 8 , P 9 , P 10When a plurality of each are combined (when m or n or l is an integer of 2 or more), P 8 , P 9 , P 10 They may be the same as or different from each other in each case. R 40 ~R 42 each independently represents an alkyl group or a hydrocarbyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and R[[ID=1 ]] 43 ~R 45 each independently represents an alkylene group having 1 to 20 carbon atoms. m, n, and l each independently represent an integer of 1 to 3, and (m + n + l) represents an integer of 3 or more.

[0108]

Chemical formula

[0109]

Chemical formula

[0110] In the above formulas (9-1) to (9-2), P 11 ~P 14 is a polymer chain, which is a fork-shaped part [A] having a main chain branched structure or a linear polymer chain having no branched structure. P 11 , P 12 When a plurality of each are combined (when o or p is an integer of 2 or more), P 11 , P 12 They may be the same as or different from each other in each case. R 46 ~R 48 each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, and R 49 , and R 51 each independently represents an alkyl group or a hydrocarbyl group having 1 to 20 carbon atoms, and R 53 and R 56 each independently represents an alkylene group having 1 to 20 carbon atoms, and R 55This represents an alkyl group or trialkylsilyl group having 1 to 20 carbon atoms, and may be substituted with an organic group containing S, O, or N that does not have active hydrogen, and may have an unsaturated bond, and may be the same or different. o represents an integer between 1 and 3, p represents 1 or 2, and t represents an integer between 1 and 3. When multiple instances of each exist in R 46 ~R 56 o, p, and t are independent of each other and may be the same or different. q represents an integer between 0 and 6, r represents an integer between 0 and 6, s represents an integer between 0 and 6, and (q+r+s) is an integer between 4 and 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 oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and not possessing active hydrogen.

[0111] In the above formulas (9-1) to (9-2), A is preferably represented by any of the following general formulas (I) to (IV).

[0112] [ka]

[0113] In the above formula (I), B 1 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and u represents an integer from 1 to 10. When multiple B groups exist, 1 They are all independent of each other.

[0114] [ka]

[0115] In the above formula (II), B 2 B represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms. 3 represents an alkyl group with 1 to 20 carbon atoms, and u represents an integer from 1 to 10. When multiple instances of each exist, B2 and B 3 They are all independent of each other.

[0116] [ka]

[0117] In the above formula (III), B 4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and u represents an integer from 1 to 10. When multiple B groups exist, 4 They are all independent of each other.

[0118] [ka]

[0119] In the above formula (IV), B 5 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and u represents an integer from 1 to 10. When multiple B groups exist, 5 They are all independent of each other.

[0120] [Molded body] The molded article of this embodiment is a molded article containing the conjugated diene polymer of this embodiment described above. From the viewpoint of ease of handling, the molded article is preferably in the form of a sheet or a block. The size and thickness of the sheet-like or block-like molded body are not particularly limited, but for example, a sheet-like molded body with a thickness of approximately 1 cm, 1,000 cm² 3 Examples include rectangular or cubic block-shaped molded bodies. The molded body of this embodiment is more preferably a block-shaped molded body, and the block shape is preferably a roughly rectangular parallelepiped, 1,000 cm 3 It is even more preferable that the molded body is in the form of a block (bale) as described above. Furthermore, it is even more preferable that it is a rectangular bale weighing between 17.5 kg and 35 kg.

[0121] The molding method for the molded article of this embodiment is, for example, a method for forming a molded article with a specific surface area of ​​0.7 m².2 / g ~ 3.2 m 2 It is preferable to produce crumbs that are / g and compress-mold the crumbs. From the perspective of moldability, it is further preferable to perform a sieving step on the crumbs before molding. When the crumbs are compress-molded, the crumbs adhere to each other, so the specific surface area of the molded body is smaller than that of the crumbs. The adhesion of the crumbs during compression molding can be controlled by adjusting the molecular weight, composition, and structure of the conjugated diene polymer, the rubber softening agent composition, the temperature and pressure during compression, etc. For example, when it is desired to increase the adhesion of the crumbs and decrease the specific surface area of the veil, it is preferable to apply conditions such as decreasing the molecular weight of the conjugated diene polymer, increasing the amount of the rubber softening agent, and increasing the temperature and pressure during compression.

[0122] The specific surface area of the molded body of the present embodiment is preferably 0.005 to 0.05 m 2 / g, and more preferably 0.01 to 0.04 m from the perspective of film packaging property 2 / g. When the specific surface area of the molded body is 0.005 m 2 / g or more, the expansion of the veil is suppressed, and when the specific surface area of the molded body is 0.05 m 2 / g or less, it is preferable because the peeling of the crumbs from the molded body is reduced. The specific surface area of the molded body can be determined by the BET method. Usually, since the specific surface area of a large-sized molded body may vary depending on the location, it is preferable to collect it from near the central part of the molded body.

[0123] Before molding the crumbs, it is preferable to sieve them by particle size and then mix them in an appropriate quantitative ratio. When the specific surface area of the molded body formed using the crumbs after desolventization exceeds the upper limit of the above range, it is preferable to increase the composition of the large-particle-size crumbs and decrease the composition of the small-particle-size crumbs among the sieved crumbs. When it is less than the lower limit, it is preferable to decrease the composition of the large-particle-size crumbs and increase the small-particle-size crumbs.

[0124] The molding compression pressure of the molded body is preferably 3 to 30 MPa, more preferably 10 to 20 MPa. When the molding compression pressure is 30 MPa or less, the equipment can be designed compactly and installation efficiency is good, and when the molding compression pressure is 3 MPa or more, moldability is good. When moldability is good, the surface of the molded body is smooth, there is no delamination of the polymer after the molding process, and expansion after molding tends to be suppressed.

[0125] The temperature of the conjugated diene polymer or the rubber composition containing the conjugated diene polymer during molding is preferably 30 to 120°C, and more preferably 50 to 100°C from the viewpoint of reducing residual solvent and suppressing thermal degradation. When the molding temperature is 30°C or higher, the moldability is good, while when the temperature is 120°C or lower, gel formation due to thermal degradation of the rubber composition is suppressed, which is preferable. The higher the temperature and pressure during molding, the smaller the specific surface area of ​​the bale. The holding pressure time during molding is preferably 3 to 30 seconds, and more preferably 5 to 20 seconds. Production efficiency is good when the holding pressure time during compression is 30 seconds or less, and moldability is good when it is 5 seconds or more.

[0126] To avoid the molded bodies from sticking together, it is preferable to package the molded bodies of this embodiment with a resin film (packaging sheet). The film resin can be made from, for example, polyethylene, ethylene copolymer resin, polystyrene, high-impact polystyrene, or PET. From the standpoint of ease of handling during transportation of the molded product and the prevention of condensation from occurring in the gap between the packaging sheet and the bale, good adhesion of the packaging sheet is preferable. The molded article of this embodiment is used, for example, in applications where it is stored in a transport container. It is preferable that the expansion rate of the molded article after one day has elapsed since molding is less than 5%, as this ensures good storage in the container.

[0127] The sheet-like or block-like molded articles using the conjugated diene polymer of this embodiment may have a softening agent component added, as described later. However, in the molded articles of this embodiment, from the viewpoint of improving the degree of compounding freedom during the production of the rubber composition described later, it is preferable that the amount of the softening agent component be 2 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1 part by mass or less, even more preferably less than 1 part by mass, and most preferably no softening agent component is added. In addition, the softening agent component used in the manufacture of the rubber composition described later may be referred to as "rubber softening agent." This is merely a wording distinction from the softening agent component used in molded articles of conjugated diene polymers, and does not distinguish the material itself.

[0128] [Method for producing conjugated diene polymers] The method for producing the conjugated diene polymer of this embodiment will be described in detail below. The above-mentioned conjugated diene polymer can be reliably and easily obtained by using the method for producing the conjugated diene polymer of this embodiment. However, the conjugated diene polymer of this embodiment is not limited to those produced by the following method.

[0129] The method for producing the conjugated diene polymer of this embodiment comprises the steps of: polymerizing a conjugated diene compound and, if necessary, a vinyl aromatic compound using an organometallic compound, including an organolithium compound, as a polymerization initiator; adding a branching agent to obtain a conjugated diene polymer having a branched structure (hereinafter, this may be collectively referred to as the polymerization branching step); and adding a coupling modifier. In the method for producing the conjugated diene polymer of this embodiment, it is preferable to add two or more coupling modifiers with different coupling numbers.

[0130] The polymerization reaction of the conjugated diene compound and the aromatic vinyl compound is preferably carried out by a growth reaction via living anionic polymerization, thereby obtaining a conjugated diene polymer having active ends. As a result, when a branching agent is added, the conjugated diene polymer and the branching agent react efficiently. Furthermore, the manufacturing method of this embodiment tends to be able to carry out a highly efficient reaction even when it includes a coupling step described later.

[0131] Polymerization reaction modes are not limited to the following, but examples include batch (hereinafter also referred to as "batch") and continuous polymerization reaction modes.

[0132] In a continuous reactor, one or more connected reactors can be used. Examples of continuous reactors include tank-type and tubular-type reactors equipped with stirrers. Preferably, monomers, an inert solvent (described later), and a polymerization initiator (described later) are continuously fed into the reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymer solution is continuously discharged.

[0133] As a batch reactor, for example, a tank-type reactor with a stirrer is used. In the batch reactor, preferably, monomers, an inert solvent (described later), and a polymerization initiator (described later) are fed into the reactor, and monomers are added continuously or intermittently during polymerization as needed, to obtain a polymer solution containing the polymer in the reactor, and the polymer solution is discharged after polymerization is complete.

[0134] In the manufacturing method of this embodiment, from the viewpoint of obtaining a conjugated diene polymer having active ends in a high proportion, it is preferable to carry out the polymerization reaction by a continuous polymerization reaction mode that allows the polymer to be continuously discharged and used for the next reaction in a short time.

[0135] (Polymerization and branching process) In the method for producing the conjugated diene polymer of this embodiment, the polymerization branching step is a step in which a branching agent is added while polymerizing at least the conjugated diene compound and, if necessary, the vinyl aromatic compound, using a polymerization initiator such as an organolithium compound, as described later, to obtain a conjugated diene polymer having a branched structure. Therefore, in the polymerization branching step, before the addition of the branching agent, the polymerization reaction of at least the conjugated diene compound and the aromatic vinyl compound is the main reaction, and the branching reaction starts after the addition of the branching agent.

[0136] As monomers used in the polymerization branching step, the conjugated diene compound and vinyl aromatic compound may be at least one of the above-mentioned conjugated diene compounds and at least one of the above-mentioned vinyl aromatic compounds. Furthermore, from the viewpoint of introducing nitrogen atoms into the conjugated diene polymer, derivatives of the above-mentioned conjugated diene compound or vinyl aromatic compound that have been substituted to have at least one nitrogen atom in the molecule may be used.

[0137] While not particularly limited, organolithium compounds such as organomonolithium compounds can be used as polymerization initiators.

[0138] Examples of organic monolithium compounds include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond, depending on the bonding mode between the organic group and its lithium.

[0139] Among these, the organic monolithium compound is preferably an organic lithium compound having at least one nitrogen atom in the molecule, from the viewpoint of being able to introduce a nitrogen atom into a conjugated diene polymer, and more preferably an alkyllithium compound having a substituted amino group, or a dialkylaminolithium compound.

[0140] A substituted amino group is an amino group that does not have active hydrogen or in which the active hydrogen is protected.

[0141] Examples of the alkyllithium compound having an amino group without active hydrogen include, but are not limited to, piperidinolithium, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.

[0142] Examples of the alkyllithium compound having an amino group with protected active hydrogen include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

[0143] Examples of the dialkylaminolithium include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium-di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethylene imide, lithium pyrrolidide, lithium piperidide, lithium heptamethylene imide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.

[0144] These organic monolithium compounds having a substituted amino group can also be used as solubilized oligomeric organic monolithium compounds by reacting a small amount of a polymerizable monomer, such as a monomer of 1,3-butadiene, isoprene, or styrene.

[0145] When a polymerization initiator contains nitrogen atoms that make up an amino group, chain transfer reactions are more likely to occur during anionic polymerization, and the amount of coupling modifier reacting with the active end after polymerization is reduced. As a result, using a polymerization initiator that contains nitrogen atoms that make up an amino group tends to result in a smaller weight-average molecular weight. Therefore, the weight-average molecular weight is 35 × 10 4 The above 40 x 10 4 The above 45 x 10 4 or more, or 60 x 10 4 In the case of the above-mentioned relatively high molecular weight polymers, if a high modification rate is desired, it is preferable to react the nitrogen atoms at the weight-termining end rather than the polymerization initiation end. In other words, polymers that are relatively high molecular weight and contain nitrogen atoms at both ends tend to be difficult to produce. Depending on the weight-average molecular weight and the structure of the coupling modifier, when nitrogen atoms are present only at the termination end, the nitrogen content of the polymer is generally between 3 ppm and 500 ppm by mass.

[0146] From the viewpoint of ease of industrial availability and ease of control of polymerization reactions, alkyllithium compounds may be used as organic monolithium compounds. When such organic monolithium compounds are used, conjugated diene polymers having an alkyl group at the polymerization initiation end can be obtained.

[0147] Examples of alkyllithium compounds include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenilithium. As alkyllithium compounds, n-butyllithium and sec-butyllithium are preferred from the viewpoint of ease of industrial availability and ease of control of polymerization reactions. These organic monolithium compounds may be used individually or in combination of two or more. They may also be used in combination with other organometallic compounds.

[0148] Other organometallic compounds include, but are not limited to, alkaline earth metal compounds, alkali metal compounds other than lithium, and other organometallic compounds. Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Compounds of alkaline earth metal alkoxides, sulfonates, carbonates, and amides are also examples. Examples of organomagnesium compounds include, but are not limited to, dibutylmagnesium and ethylbutylmagnesium. Other organometallic compounds include, but are not limited to, organoaluminum compounds.

[0149] The amount of polymerization initiator added is preferably determined by the molecular weight of the target conjugated diene polymer. The number-average molecular weight and / or weight-average molecular weight can be controlled by the ratio of the monomer added to the amount of polymerization initiator added. Specifically, reducing the proportion of polymerization initiator added tends to increase the molecular weight, while increasing the proportion of polymerization initiator added tends to decrease the molecular weight.

[0150] From the viewpoint of reliably and easily obtaining the conjugated diene polymer of this embodiment, the polymerization branching step is preferably carried out in an inert solvent. Such an inert solvent is not limited to the following, but examples include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents are not limited to the following, but examples include aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; and hydrocarbons consisting of mixtures thereof.

[0151] From the viewpoint of obtaining a conjugated diene polymer in which a conjugated diene compound and a vinyl aromatic compound are randomly polymerized, the polymerization reaction in the polymerization branching step may be carried out using the following method, for example, as described in Japanese Patent Publication No. 59-140211. That is, the polymerization reaction may be started using the entire amount of the vinyl aromatic compound and a portion of the conjugated diene compound, and then the remaining conjugated diene compound may be added intermittently during the polymerization reaction.

[0152] The polymerization temperature in the polymerization reaction of the polymerization branching step is not particularly limited, but it is preferably a temperature at which living anionic polymerization proceeds. Furthermore, from the viewpoint of improving productivity, it is more preferably 0°C or higher, and even more preferably 0°C to 120°C. When the polymerization temperature in the polymerization reaction is within the above range, the reactivity with the coupling modifier in the coupling step described later tends to be sufficiently increased. From a similar viewpoint, the polymerization temperature in the polymerization reaction is even more preferably 50°C to 100°C.

[0153] In the polymerization branching step, polar compounds may be added. When polar compounds are added, there is a tendency to obtain a conjugated diene polymer in which the vinyl aromatic compound and the conjugated diene compound are copolymerized in a more random manner. Thus, because polar compounds have an effective randomization effect in the copolymerization of conjugated diene compounds and vinyl aromatic compounds, they can be used as agents to adjust the distribution of vinyl aromatic compounds and the amount of styrene blocks. Furthermore, polar compounds can promote the polymerization reaction and can also be used as vinylizing agents to control the microstructure of the conjugated diene polymer.

[0154] Thus, since polar compounds are used as vinylizing agents, randomizing agents, and polymerization accelerators, reducing the amount of polar compounds to adjust the vinylization rate or randomization rate tends to reduce the polymerization-promoting effect as well. Therefore, in methods that adjust the degree of branching of a polymer by reacting a coupling modifier with the polymerization termination ends, reducing the amount of polar compounds added increases the polymerization time and the proportion of deactivated polymerization termination ends. As a result, such methods tend to have difficulty increasing the modification rate. In other words, when attempting to adjust the degree of branching of a modified conjugated diene polymer by adjusting the amount of polar compounds added and their reaction with a coupling modifier, it tends to be difficult to control the vinylization rate and randomization rate. In this respect, the manufacturing method of this embodiment is advantageous in terms of structural design of conjugated diene polymers because it can increase the degree of branching of the polymer using a branching agent described later, allowing the degree of branching to be controlled independently of the vinylization rate and randomization rate.

[0155] Examples of polar compounds include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis(2-oxolanyl)propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, and sodium amylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used individually or in combination of two or more.

[0156] The amount of polar compound added is not particularly limited, but can be adjusted according to the amount of polymerization active ends, i.e., the amount of polymerization initiator added. Preferably, the amount of polar compound added is 0.010 moles or more and 1.0 mole or less per mole of polymerization initiator, and more preferably 0.10 moles or more and 0.70 moles or less. Within the above range, the amount of polar compound added may be 0.60 moles or less or 0.50 moles or less per mole of polymerization initiator. Alternatively, it may be 0.15 moles or more or 0.20 moles or more per mole of polymerization initiator. When the amount of polar compound added is below the above upper limit, a conjugated diene polymer with a low Tg tends to be obtained. Furthermore, when the amount of polar compound added is above the above lower limit, deactivation of polymerization active ends is suppressed, and the coupling rate in the coupling step described later tends to improve. The amount of polar compound added may be within a range that is an arbitrary combination of the above upper and lower limits.

[0157] In the method for producing the conjugated diene polymer of this embodiment, a step to remove impurities may be included before the polymerization branching step. In particular, if the monomer, polymerization initiator, and / or inert solvent described above contain allenes and acetylenes as impurities, it is preferable to include a step to remove impurities before the polymerization branching step. Including a step to remove impurities tends to yield a conjugated diene polymer with a high concentration of active ends, and tends to yield a modified conjugated diene polymer with a high modification rate in the coupling step described later. Such a step to remove impurities is not particularly limited, but for example, it may be a step of treating with an organometallic compound. Such an organometallic compound is not particularly limited, but for example, it may be an organolithium compound, and for an organolithium compound, it may be an organolithium compound, for example, it may be n-butyllithium.

[0158] In the polymerization branching step, branching is initiated in the conjugated diene polymer by adding a branching agent, as described later. After the addition of the branching agent, two reactions occur in the reaction system: a polymerization reaction in which the conjugated diene polymer grows, and a branching reaction in which the conjugated diene polymer branches. Therefore, by adjusting the type and amount of branching agent, as well as the timing of its addition, it is possible to control the weight-average molecular weight, number-average molecular weight, their ratio (Mw / Mn), and absolute molecular weight of the conjugated diene polymer obtained in the polymerization branching step, as well as the degree of branching, the number of branching points, and the number of branches at each branching point.

[0159] Furthermore, by adding a branching agent during the polymerization of the conjugated diene polymer, the total amount of active ends of the conjugated diene polymer in the reaction system can be reduced compared to the amount of polymerization initiator added. This allows for the acceleration of the initial polymerization reaction and the maintenance of the activity of the polymerization active ends, even with a small amount of added polar compound. As a result, for the conjugated diene polymer of this embodiment, where the amount of bonded vinyl aromatic monomer units and vinyl bond amounts are within the predetermined ranges described above, the coupling rate and / or modification rate of the polymerization termination ends can be easily improved. However, it is not essential to react the conjugated diene polymer of this embodiment with a coupling modification agent.

[0160] As described above, in the method for producing conjugated diene polymers of this embodiment, the amount of polar compound added can be adjusted for the purpose of controlling the microstructure, such as the amount of bonded vinyl aromatic monomer units and the amount of vinyl bonds. However, the amount of polar compound typically used to bring the amount of bonded vinyl aromatic monomer units and vinyl bonds into the predetermined range described above is insufficient from the viewpoint of maintaining the active ends of the conjugated diene polymer in the reaction system when a branching agent is not added, and it is not easy to sufficiently maintain the activity of the polymerization active ends. Furthermore, with such amounts of polar compound added, the randomization ability for vinyl aromatic compounds and conjugated diene compounds is not sufficiently high, and in the conjugated diene polymer of this embodiment, where the amount of bonded vinyl aromatic monomer units and vinyl bonds are within the predetermined range described above, the polymerization ends tend to become vinyl aromatic monomer units. In such a state, it tends to be difficult to obtain conjugated diene polymers with a high coupling rate or modification rate. In other words, in the method for producing conjugated diene polymers of this embodiment, since a branching agent is used, even with the amount of polar compound added, which is usually not easy to maintain the activity of the polymerization active ends, the active ends of the polymer can be sufficiently maintained, and a high coupling rate and denaturation rate can be achieved.

[0161] The timing of adding the branching agent in the branching process is not particularly limited and can be appropriately selected depending on the intended use of the conjugated diene polymer being manufactured. From the viewpoint of improving the absolute molecular weight of the resulting conjugated diene polymer and the modification rate in the coupling step, the timing of adding the branching agent is preferably when the raw material conversion rate is 20% or more after the addition of the polymerization initiator, more preferably 40% or more, even more preferably 50% or more, even more preferably 65% ​​or more, and even more preferably 75% or more. In other words, the timing of adding the branching agent is preferably when the polymerization reaction is sufficiently stable. By adding the branching agent within the above range, a conjugated diene polymer with an even higher modification rate in the coupling step can be obtained even with a small amount of polar compound added, or even without adding any polar compound at all.

[0162] The branching agent is not particularly limited, but for example, a compound represented by formula (10) or formula (11) below can be used.

[0163] [ka]

[0164] [ka]

[0165] (In formula (10), R 1 This represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. R 2 ~R 3 Each of these independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. When multiple Rs exist 1 ~R 3 They are all independent of each other. X 1 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m+n+l) represents 3. (In formula (11), R 4 ~R 7 Each of these independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part. When multiple Rs exist 4 ~R 7 They are all independent of each other. X 2 ~X 3 This represents an independent halogen atom. m represents an integer between 0 and 2, n represents an integer between 0 and 3, and l represents an integer between 0 and 3. (m+n+l) represents 3. a represents an integer between 0 and 3, b represents an integer between 0 and 2, and c represents an integer between 0 and 3. (a + b + c) equals 3.

[0166] In this embodiment, the branching agent used to construct the main chain branched structure of the conjugated diene polymer is R of formula (10) above, from the viewpoint of polymerization continuity and improvement of branching degree. 1 Preferably, the compound is a hydrogen atom and m=0.

[0167] Furthermore, in this embodiment, the branching agent used to construct the main chain branched structure of the conjugated diene polymer is preferably a compound in formula (11) where m=0 and b=0, from the viewpoint of improving the degree of branching.

[0168] Furthermore, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is R of formula (10) above, from the viewpoint of polymerization continuity, modification rate and degree of branching. 1 It is more preferable that the compound is a hydrogen atom, m=0, and l=0.

[0169] Furthermore, in this embodiment, the branching agent used to construct the main chain branched structure of the conjugated diene polymer is more preferably a compound of formula (11) where m=0, l=0, a=0, and b=0, from the viewpoint of improving the modification rate and degree of branching.

[0170] Furthermore, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is R in formula (10) above, from the viewpoint of polymerization continuity, modification rate and degree of branching. 1 It is more preferable that the compound is a hydrogen atom, l=0, and n=3.

[0171] The branching agent represented by formula (10) is not limited to the following, but examples include 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, tripbutoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane Phenyl)silane, trimethoxy(2-vinylphenyl)silane, triethoxy(2-vinylphenyl)silane, tripropoxy(2-vinylphenyl)silane, tripbutoxy(2-vinylphenyl)silane, triisopropoxy(2-vinylphenyl)silane, dimethoxymethyl(4-vinylphenyl)silane, diethoxymethyl(4-vinylphenyl)silane, dipropoxymethyl(4-vinylphenyl)silane, dibutoxymethyl(4-vinylphenyl)silane, diisopropoxymethyl(4-vinylphenyl)silane, dimethoxymethyl (3-vinylphenyl)silane, diethoxymethyl(3-vinylphenyl)silane, dipropoxymethyl(3-vinylphenyl)silane, dibutoxymethyl(3-vinylphenyl)silane, diisopropoxymethyl(3-vinylphenyl)silane, dimethoxymethyl(2-vinylphenyl)silane, diethoxymethyl(2-vinylphenyl)silane, dipropoxymethyl(2-vinylphenyl)silane, dibutoxymethyl(2-vinylphenyl)silane, diisopropoxymethyl(2-vinylphenyl)silane, dimethylmethoxy(4-vinylphenyl phenyl)silane, dimethylethoxy(4-vinylphenyl)silane, dimethylpropoxy(4-vinylphenyl)silane, dimethylbutoxy(4-vinylphenyl)silane, dimethylisopropoxy(4-vinylphenyl)silane, dimethylmethoxy(3-vinylphenyl)silane, dimethylethoxy(3-vinylphenyl)silane, dimethylpropoxy(3-vinylphenyl)silane, dimethylbutoxy(3-vinylphenyl)silane, dimethylisopropoxy(3-vinylphenyl)silane, dimethylmethoxy(2-vinylphenyl)silane,Examples include dimethylethoxy(2-vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, and dimethylisopropoxy(2-vinylphenyl)silane.

[0172] Furthermore, the branching agent represented by formula (10) includes trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, tripropoxy(4-isopropenylphenyl)silane, tripbutoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl)silane, triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tripbutoxy(3-isopropenylphenyl) Silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl)silane, triethoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tributoxy(2-isopropenylphenyl)silane, triisopropoxy(2-isopropenylphenyl)silane, dimethoxymethyl(4-isopropenylphenyl)silane, diethoxymethyl(4-isopropenylphenyl)silane, dipropoxymethyl(4-isopropenylphenyl)silane, dibutoxy Dimethyl(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, dip Ropoxymethyl(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, dimethylisopropoxy(4-isopropenylphenyl)silane, dimethylmethoxy(3-isopropenylphenyl)silane,Dimethylethoxy(3-isopropenylphenyl)silane, dimethylpropoxy(3-isopropenylphenyl)silane, dimethylbutoxy(3-isopropenylphenyl)silane, dimethylisopropoxy(3-isopropenylphenyl)silane, dimethylmethoxy(2-isopropenylphenyl)silane, dimethylethoxy(2-isopropenylphenyl)silane, dimethylpropoxy(2-isopropenylphenyl)silane, dimethylbutoxy(2-isopropenylphenyl)silane, dimethylisopropoxy(2-isopropenylphenyl)silane, trichloro(4-vinylphenyl)silane, trichloro(3-vinylphenyl)silane, trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl) Examples include ylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane, dichloromethyl(4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl(2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo(3-vinylphenyl)silane, and dimethylbromo(2-vinylphenyl)silane.

[0173] Among these, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, and trichloro(4-vinylphenyl)silane are preferred, and trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, and triisopropoxy(4-vinylphenyl)silane are more preferred.

[0174] The branching agent represented by formula (11) is not limited to the following, but includes, for example, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-trippropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(2- Examples include trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(2-tripentoxysilylphenyl)ethylene, 1,1-bis(2-triisopropoxysilylphenyl)ethylene, 1,1-bis(4-(dimethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dipropylmethoxysilyl)phenyl)ethylene, 1,1-bis(4-(dimethylethoxysilyl)phenyl)ethylene, 1,1-bis(4-(diethylethoxysilyl)phenyl)ethylene, and 1,1-bis(4-(dipropylethoxysilyl)phenyl)ethylene.

[0175] Among these, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-trippropoxysilylphenyl)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.

[0176] The amount of branching agent added is not particularly limited and can be appropriately selected depending on the intended use of the conjugated diene polymer, but it is preferably 0.020 moles or more and 0.50 moles or less, more preferably 0.025 moles or more and 0.40 moles or less, and even more preferably 0.030 moles or more and 0.25 moles or less per mole of polymerization initiator. The amount of branching agent added may be 0.040 moles or more or 0.045 moles or more per mole of polymerization initiator, within the above range. Alternatively, it may be 0.20 moles or less or 0.18 moles or less per mole of polymerization initiator. The amount of branching agent added may be within a range arbitrarily determined by combining the above upper and lower limits. The amount of branching agent added affects the overall degree of branching of the conjugated diene polymer; as the amount added increases, the overall degree of branching and the degree of branching at the extreme values ​​increase.

[0177] In the polymerization branching step, the reaction temperature may or may not be changed after adding the branching agent.

[0178] In the polymerization branching step, after adding the branching agent, monomers which are raw materials for the conjugated diene polymer may be added further, and then the branching agent may be added again, and the addition of branching agents and monomers may be repeated.

[0179] The monomer to be added is not particularly limited, but from the viewpoint of improving the modification rate in the coupling process, it is preferable to add the same monomer that was initially added as a monomer in the polymerization branching process. The amount of additional monomer may be 1.0% or more, 5.0% or more, 10% or more, 15% or more, or 20% or more of the total amount of monomers used in the conjugated diene polymer. Alternatively, the amount of additional monomer may be 50% or less, 40% or less, or 35% or less. When the amount of added monomer falls within the above range, the molecular weight between the branching point created by the addition of the branching agent and the branching point created by the addition of the coupling modifier becomes longer, making it easier to obtain a highly linear molecular structure. By making the resulting conjugated diene polymer such a structure, the entanglement of the molecular chains of the conjugated diene polymer increases when it is vulcanized, making it easier to obtain a vulcanized product with excellent wear resistance, handling stability, and fracture strength.

[0180] (Coupling process) In the method for producing the conjugated diene polymer of this embodiment, it is preferable to modify the conjugated diene polymer having a branched structure obtained by the polymerization branching step described above by reacting it with a coupling modifier. Through such a coupling step, the conjugated diene polymer having a branched structure obtained by the polymerization branching step can be modified with a nitrogen atom-containing functional group that has affinity or bonding reactivity to the filler. Furthermore, multiple conjugated diene polymers can be coupled. Therefore, by a production method having such a coupling step, the conjugated diene polymer of this embodiment that exhibits the above-described effects can be obtained more reliably and simply.

[0181] The coupling modifier is not particularly limited as long as it is a reactive compound having two or more functional groups that have a nitrogen atom-containing functional group having affinity or bonding reactivity to the filler and can react with the active end of the conjugated diene polymer. Examples of such coupling modifiers include coupling modifiers that contain nitrogen atoms and, furthermore, have groups containing nitrogen atoms and silicon atoms.

[0182] Examples of coupling modifiers having a nitrogen atom-containing group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen atom-containing carbonyl compounds, nitrogen atom-containing vinyl compounds, nitrogen atom-containing epoxy compounds, imine compounds, and nitrogen atom-containing alkoxysilane compounds.

[0183] Examples of coupling modifiers having a preferred nitrogen atom-containing group include amine compounds without active hydrogen, protected amine compounds in which the active hydrogen is substituted with a protecting group, imine compounds having the general formula -N=C structure, and alkoxysilane compounds bonded to these nitrogen atom-containing compounds. Examples of amine compounds without active hydrogen include tertiary amine compounds.

[0184] Examples of isocyanate compounds include, but are not limited to, 2,4-tole diisocyanate, 2,6-tole diisocyanate, diphenylmethane diisocyanate, polymeric type diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, and 1,3,5-benzene triisocyanate.

[0185] Examples of isothiocyanate compounds include, but are not limited to, 2,4-tole diisothiocyanate, 2,6-tole diisothiocyanate, diphenylmethane diisothiocyanate, phenyl isothiocyanate, isophorone diisothiocyanate, hexamethylene diisothiocyanate, butyl isothiocyanate, and 1,3,5-benzene triisothiocyanate.

[0186] Examples of isocyanuric acid derivatives include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinan-2,4,6-trione, and 1,3,5-tris(isocyanatomethyl)-1,3,5-triazinan-2,4,6-trione, and 1,3,5-trivinyl-1,3,5-triazinan-2,4,6-trione.

[0187] Examples of nitrogen atom-containing carbonyl compounds include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, and methyl-2-pyrid Examples include lucetone, methyl-4-pyridylketone, propyl-2-pyridylketone, di-4-pyridylketone, 2-benzoylpyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, N,N-diethylcarbamate methyl, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylpicolinic acid amide, and N,N-dimethylisonicotinamide.

[0188] Examples of nitrogen atom-containing vinyl compounds include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N,N-bistrimethylsilylacrylamide, morpholinocrylamide, 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.

[0189] Examples of nitrogen atom-containing epoxy compounds include, but are not limited to, hydrocarbon compounds containing epoxy groups bonded to amino groups. Furthermore, the hydrocarbon compound containing the epoxy group bonded to the amino group may further have an epoxy group bonded to the ether group. Examples of such nitrogen atom-containing epoxy compounds are, but are not limited to, the compounds represented by the following formula (12).

[0190] [ka]

[0191] In formula (12), R is a divalent or greater organic group having at least one polar group selected from a divalent or greater hydrocarbon group, or an oxygen-containing polar group such as an ether, epoxy, or ketone, a sulfur-containing polar group such as a thioether or thioketone, or a nitrogen-containing polar group such as a tertiary amino group or imino group.

[0192] The hydrocarbon group with two or more valent values ​​is a hydrocarbon group that may be saturated or unsaturated, linear, branched, or cyclic, and includes alkylene groups, alkenylene groups, phenylene groups, etc. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. Examples include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, p-phenylene, m-, p-xylene, bis(phenylene)-methane, etc.

[0193] In the above equation (12), R 24 , R 27 R is a hydrocarbon group having 1 to 10 carbon atoms. 24 , R 27 They may be the same or different from each other. In the above equation (12), R 25 , R 28 R is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms. 25 , R 28 They may be the same or different from each other. In the above equation (12), R 26 This is a hydrocarbon group having 1 to 10 carbon atoms, or a structure of the following formula (13). R 24 , R 25 , R 26 These may be interconnected ring structures. Also, R 26 If R is a hydrocarbon group, it may be a cyclic structure bonded to R. In the case of the aforementioned cyclic structure, R 26The N and R that are bonded together may be directly bonded to each other. In the above formula (12), f is an integer greater than or equal to 1, and g is 0 or an integer greater than or equal to 1.

[0194] [ka]

[0195] In the above equation (13), R 29 , R 30 R in equation (12) above is 24 , R 25 Defined similarly, R 29 , R 30 They may be the same or different from one another.

[0196] The nitrogen atom-containing epoxy compounds mentioned above are preferably nitrogen atom-containing epoxy compounds having one or more diglycidylamino groups and one or more glycidoxy groups in the molecule.

[0197] Examples of nitrogen atom-containing epoxy compounds include, but are not limited to, N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxycyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidoxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-m-xylenediamine. Examples include 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylamino)cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperazinyl)-(N,N-diglycidyl)aniline, 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N,N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N,N-diglycidylaniline, N,N-diglycidylorthotoluidine, and N,N-diglycidylaminomethylcyclohexane. Among these, preferred candidates include N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

[0198] The imine compounds that are coupling modifiers having a group containing a nitrogen atom are not limited to the following, but include, for example, N-butylpropane-2-imine, N-butyl-4-methylpentane-2-imine, N,N'-(propane-1,3-diyl)bis(4-methylpentane-2-imine), N,N'-(hexane-1,6-diyl)bis(4-methylpentane-2-imine), and tris[2-(propane-2-ylideneamino Examples include ethylamine, tris[2-(propane-2-ylideneamino)propyl]amine, N,N'-(1,4-phenylene)bis(4-methylpentane-2-imine), 1,1'-(1,4-phenylene)bis(N-propylethane-1-imine), N,N'-(propane-1,3-diyl)bis(1-phenylmethaneimine), and N,N'-(hexane-1,6-diyl)bis(1-phenylmethaneimine).

[0199] The nitrogen atom-containing alkoxysilane compounds that are coupling modifiers having a group containing a nitrogen atom are not limited to the following, but include, for example, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, and 3-(4-methyl-1-piperazino)propyltriethoxysilane. (Razino)propyltrimethoxysilane, 1-[3-(triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 3-dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, bis(3-dimethoxymethylsilylpropyl)-N-methylamine, bis Su(3-trimethoxysilylpropyl)-N-methylamine, bis(3-triethoxysilylpropyl)methylamine, tris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N',N'-tetra(3-trimethoxysilylpropyl)ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl Ropyl)-1-aza-2-silacyclopentane, 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,Examples include 6-dioxa-2-silacyclooctane and 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silacyclooctane.

[0200] Preferred nitrogen atom-containing alkoxysilane compounds include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine ("N,N,N',N'-tetrakis(3-trimethoxy Also known as "silylpropyl)-1,3-propanediamine," Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl [3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, pentakis(3-trimethoxy Sisilylpropyl)-diethylenetriamine, Tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, Tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, Tris[3-(2,[2-Dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, 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)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, Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] phosphate, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-(trimethoxysilyl)-1-propanamine, N-benzylidene-3-(triethoxysilyl)propan-1-amine, N-be Examples include benzylidene-3-(trimethoxysilyl)propan-1-amine, 1,1-(1,4-phenylene)bis(N-(3(triethoxysilyl)propyl)methaneamine), 1,1-(1,4-phenylene)bis(N-(3(trimethoxysilyl)propyl)methaneamine), 2-methoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, and 2-methoxy-2-methyl-1-(4-methoxybenzylideneaminoethyl)-1-aza-2-silacyclopentane.

[0201] Among coupling modifiers having a group containing a nitrogen atom, protected amine compounds in which the active hydrogen is substituted with a protecting group include compounds having an unsaturated bond and a protected amine in the molecule. Such compounds are not limited to the following, but include, for example, 4,4'-vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(triethylsilyl)aniline], Examples include 4,4'-vinylidenebis[N-ethyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(t-butyldimethylsilyl)aniline], 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N-methyl-N-(trimethylsilyl)aminophenyl]ethylene, and 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethylaminophenyl]ethylene.

[0202] Among coupling modifiers having a group containing a nitrogen atom, protected amine compounds in which active hydrogen is substituted with a protecting group include alkoxysilanes and compounds having a protected amine in their molecule. Such compounds 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, and N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane. Nopropylmethyldiethoxysilane, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-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-tri Methoxysilylbutyl)-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, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl) Examples include toxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-ethylidene-3-(triethoxysilyl)-1-propanamine, and N-ethylidene-3-(trimethoxysilyl)-1-propanamine.

[0203] Also, N-ethylidene-3-methyl(dimethoxysilyl)-1-propanamine, N-ethylidene-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-methyl(dimethoxysilyl)-1-propanamine N-(1-methylpropyridene)-3-methyl(diethoxysilyl)-1-propanamine, N-benzylidene-3-methyl(dimethoxysilyl)propan-1-amine, N-benzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(triethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(trimethoxysilyl)propan-1-amine, N -4-methylbenzylidene-3-methyl(dimethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-naphthylidene-3-(triethoxysilyl)propan-1-amine, N-naphthylidene-3-(trimethoxysilyl)propan-1-amine, N-naphthylidene-3-methyl(dimethoxysilyl)propan-1-amine, 1,1-(1,4-methylbenzylidene-3-methyl(dimethoxysilyl)propan-1-amine, 1,1-(1,4-methylbenzylidene-3-methyl(dimethoxysilyl)propan-1-amine) Examples include nilen)bis(N-(3-methyl(dimethoxysilyl)propyl)methaneamine), 1,1-(1,4-phenylene)bis(N-(3-methyl(diethoxysilyl)propyl)methaneamine), 2-ethoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, and 2-methoxy-2-methyl-1-(methylisobutylideneaminoethyl)-1-aza-2-silacyclopentane.

[0204] In the coupling process, it is more preferable to use a combination of two or more nitrogen atom-containing alkoxysilane compounds represented by any of the following formulas (14) to (18) as coupling modifiers. As such a coupling modifier, a coupling modifier having two or fewer alkoxysilyl groups and a coupling modifier having more than two alkoxysilyl groups can be used in combination.

[0205] [ka]

[0206] In formula (14), R 8 ~R 10 R is a hydrocarbon group having 1 to 20 carbon atoms, which may have unsaturated bonds and may be the same or different. 11 , R 12 R is an aliphatic hydrocarbon group having 1 to 6 carbon atoms, which may have unsaturated bonds and may be the same or different. 13 is a hydrocarbon group having 1 to 20 carbon atoms, which may contain Si, O, or N and may be substituted with an organic group that does not have active hydrogen, and may have an unsaturated bond. d is an integer from 1 to 3.

[0207] [ka]

[0208] In formula (15), R 14 ~R 16 These are hydrocarbon groups having 1 to 20 carbon atoms, which may have unsaturated bonds and may be the same or different from each other. R 17 , R 18 is a hydrocarbon group having 1 to 20 carbon atoms, containing Si, O, or N, which may be substituted with an organic group that does not have active hydrogen, and may have an unsaturated bond. e is an integer from 1 to 3.

[0209] [ka]

[0210] In formula (16), R 31 ~R 34 Each independently represents an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, R 35 This represents an alkylene group with 1 to 10 carbon atoms, R 36 This represents an alkylene group with 1 to 20 carbon atoms. h represents an integer between 1 and 3, i represents an integer of 1 or 2, and (h+i) represents an integer of 4 or greater. R when multiple values ​​exist. 31 ~R 34 They are all independent of each other.

[0211] [ka]

[0212] In formula (17), R 37 ~R 42 Each independently represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, R 43 ~R 45 Each of these independently represents an alkylene group having 1 to 20 carbon atoms. m, n, and l each independently represent integers from 1 to 3, and (m+n+l) represents an integer greater than or equal to 4. R when multiple such integers exist. 37 ~R 42 They are all independent of each other.

[0213] [ka]

[0214] In formula (18), R 46 ~R 48 Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R 49 ~R 52 Each independently represents an alkyl group having 1 to 20 carbon atoms, and R 53 and R 56 Each independently represents an alkylene group having 1 to 20 carbon atoms, R 54R represents an alkylene group or alkoxy group having 1 to 20 carbon atoms. 55 This represents an alkyl group or trialkylsilyl group having 1 to 20 carbon atoms. 'o' represents an integer between 1 and 3, and 'p' represents either 1 or 2. When multiple instances of each exist in R 46 ~R 56 , o, and p are independent of each other and may be the same or different. q represents an integer between 0 and 6, r represents an integer between 0 and 6, s represents an integer between 0 and 6, and (q+r+s) is an integer between 4 and 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 oxygen, nitrogen, silicon, sulfur, and phosphorus atoms, and not possessing active hydrogen.

[0215] The coupling modifier represented by formula (14) is not limited to the following, but examples include 1-methyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-methyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-ethyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-ethyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-propyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-propyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-butyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-butyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-trimethylsilyl Examples include 4-(3-(trimethoxysilyl)propyl)piperazine, 1-trimethylsilyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-triethylsilyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-triethylsilyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-(t-butyldimethylsilyl)-4-(3-(trimethoxysilyl)propyl)piperazine, 1-(t-butyldimethylsilyl)-4-(3-(triethoxysilyl)propyl)piperazine, 1-triisopropylsilyl-4-(3-(trimethoxysilyl)propyl)piperazine, and 1-triisopropylsilyl-4-(3-(triethoxysilyl)propyl)piperazine.

[0216] Among these, those in formula (14) where d is 3 are preferred from the viewpoint of enhancing the reactivity and interaction between the conjugated diene polymer and inorganic fillers such as silica, and from the viewpoint of improving processability. Specifically, 1-methyl-4-(3-(trimethoxysilyl)propyl)piperazine and 1-methyl-4-(3-(triethoxysilyl)propyl)piperazine are preferred.

[0217] The reaction temperature, reaction time, etc., when reacting the coupling modifier having a nitrogen atom-containing group represented by formula (14) with the polymerization active end are not particularly limited, but it is preferable to react at 0°C to 120°C for 30 seconds or more.

[0218] The amount of coupling modifier represented by formula (14) added is the amount of the alkoxy group (OR) bonded to the silyl group in the compound represented by formula (14). 8 The total number of moles of ) is preferably in the range of 0.2 to 2.5 times the number of moles of polymerization initiator added, more preferably in the range of 0.5 to 2.0 times, and even more preferably in the range of 1.0 to 2.0 times. From the viewpoint of making the modification rate and molecular weight of the resulting conjugated diene polymer even more favorable, it is preferable to have it be 0.2 times or more. Also, from the viewpoint of suppressing a decrease in processability due to an excessively high degree of branching, it is preferable to have it be 2.5 times or less.

[0219] More specifically, the amounts of polymerization initiator and coupling modifier represented by formula (14) added should be adjusted so that the number of moles of polymerization initiator is preferably 1.5 times or more, more preferably 1.7 times or more, than the number of moles of coupling modifier represented by formula (14).

[0220] The coupling modifier represented by formula (15) is not limited to the following, but examples include N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-ethylidene-3-(trimethoxysilyl)-1-propanamine, N-ethylidene-3-(trimethoxysilyl) Xysilyl)-1-propanamine, N-ethylidene-3-methyl(dimethoxysilyl)-1-propanamine, N-ethylidene-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1-methylpropyridene)-3-methyl(diethoxysilyl)-1-propanamine N-benzylidene-3-(triethoxysilyl)propan-1-amine, N-benzylidene-3-(trimethoxysilyl)propan-1-amine, N-benzylidene-3-methyl(dimethoxysilyl)propan-1-amine, N-benzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(triethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-(trimethoxysilyl)propan-1-amine, N-4-methylbenzylidene-3-methyl(dimethoxysilyl)propan -1-amine, N-4-methylbenzylidene-3-methyl(diethoxysilyl)propan-1-amine, N-naphthylidene-3-(triethoxysilyl)propan-1-amine, N-naphthylidene-3-(trimethoxysilyl)propan-1-amine, N-naphthylidene-3-methyl(dimethoxysilyl)propan-1-amine, 1,1-(1,4-phenylene)bis(N-(3(triethoxysilyl)propyl)methaneamine), 1,1-(1,Examples include 4-phenylene)bis(N-(3-methyl(dimethoxysilyl)propyl)methaneamine), 1,1-(1,4-phenylene)bis(N-(3-methyl(diethoxysilyl)propyl)methaneamine), 2-methoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, 2-methoxy-2-methyl-1-(p-methoxybenzylideneaminoethyl)-1-aza-2-silacyclopentane, 2-ethoxy-2-methyl-1-(benzylideneaminoethyl)-1-aza-2-silacyclopentane, and 2-methoxy-2-methyl-1-(methylisobutylideneaminoethyl)-1-aza-2-silacyclopentane.

[0221] The reaction temperature, reaction time, etc., when reacting the coupling modifier having a nitrogen atom-containing group represented by formula (15) with the polymerization active end are not particularly limited, but it is preferable to react at 0°C to 120°C for 30 seconds or more.

[0222] The amount of coupling modifier represented by formula (15) added is the amount of the alkoxy group (OR) bonded to the silyl group in the compound represented by formula (15). 14 The total number of moles of ) is preferably in the range of 0.2 to 2.5 times the number of moles of polymerization initiator added, more preferably in the range of 0.5 to 2.0 times, and even more preferably in the range of 1.0 to 2.0 times. From the viewpoint of making the modification rate and molecular weight of the resulting conjugated diene polymer even more favorable, it is preferable to have it be 0.2 times or more. Also, from the viewpoint of suppressing a decrease in processability due to an excessively high degree of branching, it is preferable to have it be 2.5 times or less.

[0223] More specifically, the amounts of polymerization initiator and coupling modifier represented by formula (15) added should be adjusted so that the number of moles of polymerization initiator is preferably 1.5 times or more, more preferably 1.7 times or more, than the number of moles of coupling modifier represented by formula (15).

[0224] The coupling modifier having a group containing a nitrogen atom represented by formula (16) is not limited to the following, but includes, for example, 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- Examples include 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.

[0225] Among these, those in formula (16) where i is 2 and h is 3 are preferred, from the viewpoint of reactivity and interaction between the functional group of the coupling modifier having a nitrogen atom-containing group and inorganic fillers such as silica, as well as from the viewpoint of processability. Specifically, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane and 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane are preferred.

[0226] In the coupling step using the coupling modifier represented by formula (16), the reaction temperature and reaction time are not particularly limited, but are preferably 0°C to 120°C and preferably 30 seconds or longer.

[0227] The amount of coupling modifier represented by formula (16) added is preferably in a range where the total number of moles of alkoxy groups bonded to the silyl group in the compound represented by formula (16) is between 0.2 and 2.5 times the number of moles of polymerization initiator added, more preferably between 0.5 and 2.0 times, and even more preferably between 1.0 and 2.0 times. From the viewpoint of making the modification rate, molecular weight, and branched structure of the resulting conjugated diene polymer even more favorable, it is preferable to set it to 0.2 times or more. Furthermore, from the viewpoint of suppressing a decrease in processability due to excessively high branching, it is preferable to set it to 2.5 times or less.

[0228] More specifically, the amounts of polymerization initiator and coupling modifier represented by formula (16) should be adjusted so that the number of moles of polymerization initiator is preferably 3.0 times or more, more preferably 4.0 times or more, than the number of moles of coupling modifier represented by formula (16).

[0229] Examples of modifiers having a nitrogen atom-containing group represented by formula (17) 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.

[0230] Among these, it is preferable that in formula (17), n, m, and l all represent 3, from the viewpoint of reactivity and interaction between the functional group of the modifier and inorganic fillers such as silica, as well as from the viewpoint of processability. Preferred specific examples include tris(3-trimethoxysilylpropyl)amine and tris(3-triethoxysilylpropyl)amine.

[0231] The reaction temperature, reaction time, etc., when reacting the modifier having a nitrogen atom-containing group represented by formula (17) with the polymerization active end are not particularly limited, but it is preferable to react at 0°C to 120°C for 30 seconds or more.

[0232] The total number of moles of alkoxy groups bonded to the silyl groups in the coupling modifier represented by formula (17) is preferably in the range of 0.2 to 2.0 times the number of moles of lithium constituting the polymerization initiator described above, more preferably in the range of 0.5 to 2.0 times, and even more preferably in the range of 0.6 to 1.6 times. From the viewpoint of obtaining a sufficient modification rate, molecular weight, and branched structure in the conjugated diene polymer, it is preferable to have a value of 0.2 times or more. In addition to the preference for coupling polymer ends to obtain branched polymer components for improved processability, it is preferable to have a value of 2.0 times or less from the viewpoint of coupling modifier cost.

[0233] More specifically, the mole count of the polymerization initiator is preferably 4.0 times or more moles, and more preferably 5.0 times or more moles, relative to the mole count of the modifier.

[0234] In formula (18) above, A is preferably represented by any of the following general formulas (i) to (iv).

[0235] [ka]

[0236] In the above equation (i), B 1 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer from 1 to 10. When multiple B groups exist... 1 They are all independent of each other.

[0237] [ka]

[0238] In the above equation (ii), B 2 B represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms. 3 represents an alkyl group with 1 to 20 carbon atoms, and t represents an integer from 1 to 10. When multiple instances of each exist, B 2 and B 3 They are all independent of each other.

[0239] [ka]

[0240] In the above formula (iii), B 4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer from 1 to 10. When multiple B groups exist... 4 They are all independent of each other.

[0241] [ka]

[0242] In the above formula (iv), B 5 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer from 1 to 10. When multiple B groups exist... 5 They are all independent of each other.

[0243] In formula (18), the coupling modifier having a nitrogen atom-containing group when A is represented by formula (i) is not limited to the following, but examples include 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, bis[3-(2,2 Examples include -diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)amine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, and tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-propanediamine.

[0244] Also, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3- Propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-triethoxysilylpropyl )-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-di Ethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, Tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, 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-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisamino Examples include methylcyclohexane, 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-propanediamine, and tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane.

[0245] Furthermore, 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-bisaminomethylcyclohexa Tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-bis[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-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]- 1,3-Bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-Bisaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,Examples include 3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, and pentakis(3-trimethoxysilylpropyl)-diethylenetriamine.

[0246] In formula (18), the coupling modifier having a nitrogen atom-containing group when A is represented by formula (ii) is not limited to the following, but examples include tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2, Examples include 2-diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N1,N1'-(propane-1,3-diyl)bis(N1-methyl-N3,N3-bis(3-(trimethoxysilyl)propyl)-1,3-propanediamine), and N1-(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N1-methyl-N3-(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N3-(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0247] In formula (18), the coupling modifier having a nitrogen atom-containing group when A is represented by formula (iii) is not limited to the following, but examples include 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-sil [3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-Methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)-bis[3-(2,2-dimethoxy-1-aza-2-sila [Clopentane)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-1 Examples include -sila-2-azacyclopentane)propyl]-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]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.

[0248] In formula (18), the modifying agent having a nitrogen atom-containing group when A is represented by formula (iv) is not limited to the following, but examples include 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.

[0249] In formula (18) above, A is preferably represented by formula (i) or formula (ii), and s represents 0.

[0250] Coupling modifiers having such nitrogen atom-containing groups tend to be readily available and tend to exhibit superior wear resistance and low hysteresis loss performance when used as vulcanized products for conjugated diene polymers. Examples of such coupling modifiers having nitrogen atom-containing groups include, but are not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-di Examples include methoxy-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-trismethoxysilylpropyl)-methyl-1,3-propanediamine.

[0251] In formula (18), A is more preferably represented by formula (i) or formula (ii), where s is 0, and in formula (i) or formula (ii), t is an integer from 2 to 10.

[0252] This tends to result in superior wear resistance and low hysteresis loss performance when vulcanized.

[0253] Such coupling modifiers having a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 Examples include -(3-(trimethoxysilyl)propyl)-1,3-propanediamine.

[0254] The amount of the compound represented by formula (18) added as a coupling modifier having a nitrogen atom-containing group can be adjusted so that the number of moles of polymerization initiator and the number of moles of coupling modifier react in the desired stoichiometric ratio, thereby tending to achieve the desired star-shaped highly branched structure.

[0255] The specific number of moles of polymerization initiator is preferably 5.0 times or more, more preferably 6.0 times or more, than the number of moles of coupling modifier.

[0256] In this case, in formula (18), the number of functional groups of the coupling modifier ((o-1) × q + p × r + s) is preferably an integer between 5 and 10, and more preferably an integer between 6 and 10.

[0257] The method for producing the conjugated diene polymer of this embodiment may include a condensation reaction step in which a condensation reaction is caused by adding a condensation accelerator after the step of adding a coupling modifier and / or before the step of adding a coupling modifier.

[0258] The method for producing the conjugated diene polymer of this embodiment may further include a modification step using a modifying agent other than the coupling modifying agent described above.

[0259] In the method for producing the conjugated diene polymer of this embodiment, two types of coupling modifiers may be added in the step of adding the coupling modifier, or three or more types may be added. When adding two types of coupling modifiers, it is preferable to use a combination of coupling modifiers with different numbers of functional groups. Furthermore, when adding three or more coupling modifiers, it is preferable to include a combination of coupling modifiers with different numbers of functional groups.

[0260] In the step of adding coupling modifiers, it is preferable to add two types of coupling modifiers with different numbers of functional groups. Examples of combinations of two coupling modifiers with different numbers of functional groups include a combination of a coupling modifier with two or fewer functional groups and a coupling modifier with three or more functional groups. A fork-shaped polymer with a long stalk is formed when a fork-shaped portion [A] and a linear polymer are bonded to one end of a bifunctional coupling modifier, and a star-shaped branched structure is formed by a trifunctional coupling modifier. Therefore, as a combination of coupling modifiers that is easy to design, it is preferable to use a combination of bifunctional and trifunctional or more coupling modifiers, taking into consideration the number of active ends after the branching agent has reacted, so that the long-stalked fork-shaped portion [A] and the star shape are in the desired ratio. It is preferable to add multiple types of coupling modifiers at the same time, and they may or may not be mixed beforehand.

[0261] Examples of coupling modifiers with two or fewer functionalities include coupling modifiers having the structures of formulas (14) and (15), and examples of coupling modifiers with three or more functionalities include coupling modifiers having the structures of formulas (16), (17), and (18), but are not particularly limited.

[0262] In view of the fact that, from the viewpoint of improving the wear resistance and fracture strength of the conjugated diene copolymer, it is preferable that the mass ratio of the conjugated diene polymer having a long-stalked fork-shaped portion [A] and not having a star-shaped polymer structure portion [B] is greater than that of the polymer having a three-branched or more star-shaped polymer structure portion [B] to which one or more fork-shaped portions [A] are bonded, the molar ratio of each coupling modifier to the polymerization initiator × number of functions is preferably 9:1 to 5:5 for the coupling modifier with two or fewer functions : the coupling modifier with three or more functions, more preferably 6:4, and even more preferably 8:2 or 7:3. By controlling the addition ratio of coupling modifiers with two or fewer functions and coupling modifiers with three or more functions, the mass ratio of the polymer having the long-stalked fork-shaped portion [A] and the polymer having the star-shaped polymer structure portion [B] can be controlled, thereby making it possible to control the molecular weight and branching degree of the entire conjugated diene copolymer. As the addition ratio of coupling modifiers with three or more functions increases, the mass ratio of polymers having star-shaped polymer structures [B] increases, and the overall molecular weight and degree of branching of the conjugated diene copolymer increase.

[0263] The method for producing the conjugated diene polymer of this embodiment may include a hydrogenation step for hydrogenating the conjugated diene portion. The method for hydrogenating the conjugated diene portion is not particularly limited, and known methods can be used.

[0264] A preferred hydrogenation process involves hydrogenating the conjugated diene portion by blowing gaseous hydrogen into the polymer solution in the presence of a catalyst. The catalysts used are not particularly limited, but examples include heterogeneous catalysts such as catalysts in which noble metals are supported on porous inorganic materials; and homogeneous catalysts such as catalysts obtained by solubilizing salts of nickel, cobalt, etc. and reacting them with organoaluminum, etc., and catalysts using metallocenes such as titanocene. Among these, titanocene catalysts are preferred from the viewpoint of being able to select milder hydrogenation conditions. Another method for hydrogenating aromatic groups is to use a catalyst supported by a precious metal.

[0265] Furthermore, a hydrogenation process that does not use gaseous hydrogen involves contacting a hydrogenation catalyst with a polymer solution. Such hydrogenation catalysts are not particularly limited, but examples include: (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, or Ru are supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts using organic acid salts of Ni, Co, Fe, or Cr, or transition metal salts such as acetylacetone salts, and reducing agents such as organoaluminum; and (3) so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, or Zr. Other hydrogenation catalysts, though not particularly limited, include known hydrogenation catalysts described in 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 Application Publication No. 8-109219. Preferred hydrogenation catalysts include reaction mixtures of titanocene compounds and reducing organometallic compounds.

[0266] In the method for producing the conjugated diene polymer of this embodiment, after the coupling step with a coupling modifier, a deactivator and / or neutralizing agent may be added to the polymer solution as needed.

[0267] Examples of inactivators include, but are not limited to, water, and alcohols such as methanol, ethanol, and isopropanol.

[0268] Examples of neutralizing agents include, but are not limited to, aqueous solutions of carboxylic acids and inorganic acids such as stearic acid, oleic acid, and versatic acid (a mixture of branched carboxylic acids with 9 to 11 carbon atoms, and mainly composed of those with 10 carbon atoms), as well as carbon dioxide.

[0269] The method for producing the conjugated diene polymer of this embodiment may include a step of obtaining the conjugated diene polymer from the polymer solution. Known methods can be used for this purpose, but for example, the following method can be used. Specifically, these methods include obtaining the polymer by separating the solvent using steam stripping, filtering the polymer, and then dehydrating and drying it; obtaining the polymer by concentrating it in a flushing tank and then defoliating it using a vent extruder or the like; and obtaining the polymer by directly defoliating it using a drum dryer or the like.

[0270] [Rubber composition] The rubber composition of this embodiment contains a rubber component comprising the conjugated diene polymer of this embodiment described above. When the conjugated diene polymer of this embodiment is incorporated into a tire, the oil contained in the veil molded body made of the conjugated diene polymer will inevitably be included in the tire. However, if the amount of oil is reduced, the amount of oil included in the tire will also decrease, which has the advantage of increasing the degree of freedom in composition during tire design. In this embodiment, a rubber softener, as described later, may be added to the conjugated diene polymer and its sheet-like or block-like molded articles. However, from the viewpoint of improving the degree of freedom in compounding design during the production of the rubber composition, it is preferable that the amount of rubber softener be 2 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1 part by mass or less, and even more preferably no rubber softener is added per 100 parts by mass of the conjugated diene polymer.

[0271] Rubber softeners are not particularly limited, but examples include stretching oils, liquid rubber, and resins.

[0272] It is preferable that the conjugated diene polymer and its sheet-like or block-like molded articles be provided without the addition of softening agents, from the viewpoint of improving the degree of freedom in compounding design during the production of rubber compositions using the molded articles. Generally, there is an upper limit to the total amount of rubber softener in a rubber composition. However, when a softener component is added to a sheet-like or block-like molded body of a conjugated diene polymer, the rubber composition produced using that molded body will also contain the softener component. This puts pressure on the total amount of rubber softener in the rubber composition and limits the freedom in selecting the type and amount of rubber softener to be added during the production of the rubber composition. From the perspective of improving the freedom in selecting the type and amount of rubber softener to match the performance required for the rubber composition, it is preferable to reduce the amount of softener component added to a sheet-like or block-like molded body of a conjugated diene polymer.

[0273] While not particularly limited, for example, by reducing the amount of the drawer oil added to the conjugated diene polymer and the sheet-like or block-like molded body thereof in this embodiment, it becomes possible to incorporate a larger amount of resin such as the drawer oil during the production of rubber compositions using these materials. This is preferable from the viewpoint of further improving the fracture strength of the rubber composition and its vulcanized product.

[0274] The rubber composition using the conjugated diene polymer of this embodiment and the sheet-like or block-like molded articles thereof may further contain a rubber stabilizer from the viewpoint of suppressing gel formation and improving stability during processing.

[0275] Rubber stabilizers are not limited to those listed below, but any known ones can be used. Examples include 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)propinate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

[0276] The rubber composition of this embodiment contains 100 parts by mass of rubber component and 5.0 to 150 parts by mass of filler. The aforementioned rubber component contains 10 parts by mass or more of the conjugated diene polymer of this embodiment per 100 parts by mass of the total amount of rubber components. By dispersing a filler in a rubber component containing the conjugated diene polymer of this embodiment, a rubber composition can be obtained that exhibits even better processability during vulcanization, and whose vulcanized product has even better low hysteresis loss, fracture characteristics, and abrasion resistance. Furthermore, by including the conjugated diene polymer of this embodiment in a predetermined proportion in the rubber component, fuel efficiency, processability, and abrasion resistance are further improved.

[0277] Examples of fillers 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. In particular, when the rubber composition of this embodiment is used for vulcanized rubber applications such as tires, vibration-damping rubber for automobile parts, and shoes, it is especially preferable to include silica-based inorganic fillers. Such fillers may be used alone or in combination of two or more.

[0278] The silica-based inorganic filler is not particularly limited, and known fillers can be used, but solid particles containing SiO2 or Si3Al as constituent units are preferred, and solid particles containing SiO2 or Si3Al as the main component of the constituent units are more preferred. Here, the main component refers to a component that is contained in the silica-based inorganic filler in an amount of more than 50% by mass, preferably 70% by mass or more, and more preferably 80% by mass or more.

[0279] Specific silica-based inorganic fillers include, but are not limited to, silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and inorganic fibrous materials such as glass fibers. Alternatively, silica-based inorganic fillers with hydrophobic surfaces and mixtures of silica-based and non-silica-based inorganic fillers may be used. Among these, silica or glass fibers are preferred, and silica is more preferred, from the viewpoint of further improving the strength and abrasion resistance of the rubber composition. While not particularly limited, silica includes, for example, dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred from the viewpoint of further improving the fracture strength of the rubber composition.

[0280] From the viewpoint of more reliably obtaining rubber compositions with practically good abrasion resistance and fracture strength, the nitrogen adsorption specific surface area required by the BET adsorption method of silica-based inorganic fillers is 100 m². 2 / g or more 300m 2 It is preferable that it be less than or equal to / g, and 170m 2 / g or more 250m 2 It is more preferable that the specific surface area be less than or equal to / g. Also, if necessary, a relatively small specific surface area (for example, a specific surface area of ​​200m²) 2 Silica-based inorganic fillers (less than / g) and those with a relatively large specific surface area (e.g., 200m²) 2 It may also be used in combination with silica-based inorganic fillers (1 / g or more). In this embodiment, in particular, a filler with a relatively large specific surface area (for example, 200m) 2 By using silica-based inorganic fillers (1 / g or more), the dispersibility of silica in conjugated diene polymers tends to improve further. As a result, the resulting rubber composition tends to have even better abrasion resistance, fracture strength, and low hysteresis loss.

[0281] Carbon blacks include, but are not limited to, the following, examples of carbon blacks from various classes such as SRF, FEF, HAF, ISAF, and SAF. Among these, those with a nitrogen adsorption specific surface area of ​​50 m² as required by the BET adsorption method are particularly desirable. 2Carbon black with a concentration of 1 / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferred.

[0282] As for metal oxides, the chemical formula is M x O y The solid particles whose main component is (where M represents a metal atom, and x and y each independently represent integers from 1 to 6) are not particularly limited, but examples include alumina, titanium oxide, magnesium oxide, and zinc oxide.

[0283] Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

[0284] The filler content in the rubber composition of this embodiment is 5.0 parts by mass to 150 parts by mass per 100 parts by mass of rubber component, preferably 20 parts by mass to 100 parts by mass, and more preferably 30 parts by mass to 90 parts by mass. When the filler is within the above range, the rubber composition tends to have even better processability during vulcanization, and the vulcanized product tends to have even better low hysteresis loss, fracture characteristics, and abrasion resistance.

[0285] From the viewpoint of reliably imparting performance required for applications such as tires, such as dry grip performance and conductivity, the rubber composition of this embodiment preferably contains carbon black in an amount of 0.5 parts by mass or more and 100 parts by mass or less per 100 parts by mass of the rubber component containing the conjugated diene polymer. From a similar viewpoint, the rubber composition preferably contains carbon black in an amount of 3.0 parts by mass or more and 100 parts by mass or less, and even more preferably 5.0 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the rubber component containing the conjugated diene polymer.

[0286] The rubber composition of this embodiment may further contain a silane coupling agent. By including a silane coupling agent in the rubber composition, the interaction between the rubber component and the filler can be further improved. As silane coupling agents, while not limited to the following, compounds having a sulfur bond and an alkoxysilyl or silanol group in one molecule are preferred. Examples of such compounds, while not limited to the following, include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.

[0287] In the rubber composition of this embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 part by mass or more and 15 parts by mass or less, per 100 parts by mass of the filler. When the content of the silane coupling agent is within the above range, the interaction between the rubber component and the filler tends to be further improved.

[0288] The rubber composition of this embodiment may also contain rubbery polymers other than the conjugated diene polymer of this embodiment (hereinafter simply referred to as "rubbery polymers") as rubbery components. The conjugated diene polymer of this embodiment and the aforementioned rubbery polymers are collectively referred to as "rubber components."

[0289] Examples of rubbery polymers include, but are not limited to, conjugated diene polymers and their hydrogenated products, random copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenated products, block copolymers of conjugated diene compounds and vinyl aromatic compounds and their hydrogenated products, non-diene polymers, and natural rubber. Note that rubbery polymers other than the conjugated diene polymers of this embodiment can be distinguished from the conjugated diene polymers of this embodiment in that they do not satisfy all of the above-mentioned conditions (i) to (iii).

[0290] Examples of rubbery polymers include, but are not limited to, but are styrene-based elastomers such as butadiene rubber and its hydrogenated derivatives, isoprene rubber and its hydrogenated derivatives, styrene-butadiene rubber and its hydrogenated derivatives, styrene-butadiene block copolymers and their hydrogenated derivatives, styrene-isoprene block copolymers and their hydrogenated derivatives, and acrylonitrile-butadiene rubber and its hydrogenated derivatives.

[0291] Examples of non-diene polymers include, but are not limited to, olefin-based elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, as well as butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α,β-unsaturated nitrile-acrylic acid ester-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

[0292] Examples of natural rubber include, but are not limited to, smoked sheets such as RSS3-5, SMR, and epoxidized natural rubber.

[0293] The rubbery polymer may be a modified rubber to which polar functional groups such as hydroxyl groups and amino groups have been added. When the rubber composition of this embodiment is used as a tire material, the rubbery polymer is preferably one or more selected from the group consisting of butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber.

[0294] The weight-average molecular weight of the rubbery polymer is preferably between 2,000 and 2,000,000, and more preferably between 5,000 and 1,500,000, from the viewpoint of balancing the abrasion resistance, fracture strength, low hysteresis loss, and processability of the rubber composition. Furthermore, a low molecular weight rubbery polymer, so-called liquid rubber, can also be used as the rubbery polymer. These rubbery polymers may be used individually or in combination of two or more.

[0295] When the rubber composition of this embodiment contains the conjugated diene polymer and the rubbery polymer of this embodiment, the content ratio (mass ratio) of the conjugated diene polymer of this embodiment to the rubbery polymer is preferably 10 / 90 or more and 100 / 0 or less (conjugated diene polymer / rubby polymer), more preferably 20 / 80 or more and 90 / 10 or less, and even more preferably 30 / 70 or more and 80 / 20 or less. In other words, the rubber component contains, preferably, 10 to 100 parts by mass, more preferably 20 to 90 parts by mass, and even more preferably 30 to 80 parts by mass, of the conjugated diene polymer of this embodiment, per 100 parts by mass of the total amount of the rubber component. When the proportion of the conjugated diene polymer contained in the rubber component is within the above range, the vulcanized product of the rubber composition tends to have even better abrasion resistance and low hysteresis loss properties.

[0296] In order to further improve the processability of the rubber composition of this embodiment, a rubber softener may be added in addition to the rubber component. Rubber softeners are not particularly limited, but examples include liquid rubber, resins, and stretching oils. The liquid rubber is not particularly limited, but examples include liquid polybutadiene and liquid styrene-butazine rubber. When liquid rubber is used as a rubber softener, in addition to the effects described above, the glass transition temperature of the rubber composition can be further reduced, which tends to further improve the wear resistance, low hysteresis loss, and low-temperature properties of the vulcanized product. Examples of resins include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, hydrocarbon resins such as mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, hydrogenated hydrocarbon resins such as hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols. These resins may be used individually or in combination of two or more. Furthermore, when hydrogenating these resins, all unsaturated groups may be hydrogenated, or some may be left intact.

[0297] When resin is used as a rubber softener, in addition to the effects described above, the fracture strength of the vulcanized rubber composition tends to be further improved. In this embodiment, from the viewpoint of further improving the fracture strength of the vulcanized product, it is preferable to add a resin as a rubber softener in addition to the rubber component.

[0298] In this embodiment, to further improve its processability, a rubber softener may be added to the rubber component, but mineral oil or a liquid or low molecular weight synthetic softener is preferred.

[0299] Examples of spreading oils include aromatic oils, naphthenic oils, and paraffinic oils. Among these, aromatic substitute oils with a polycyclic aromatic (PCA) component content of 3% by mass or less according to the IP346 method are preferred from the viewpoint of environmental safety, as well as from the viewpoint of preventing oil bleeding and improving wet grip. Aromatic substitute oils are not particularly limited, but examples include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts) as shown in Kautschuk Gummi Kunststoffe 52(12)799(1999).

[0300] Process oils or extender oils, which are mineral oil-based rubber softeners used to soften, increase the volume of, and improve the processability of rubber, are mixtures of aromatic rings, naphthenic rings, and paraffinic chains. Among these, those in which the number of carbon atoms belonging to the paraffinic chain is 50% or more of the total number of carbon atoms are called paraffinic, those in which the number of carbon atoms belonging to the naphthenic ring is 30% to 45% of the total number of carbon atoms are called naphthenic, and those in which the number of carbon atoms belonging to the aromatic ring is more than 30% of the total number of carbon atoms are called aromatic. The rubber composition of this embodiment preferably contains a rubber softener having an appropriate aromatic content. Including such a rubber softener further improves compatibility with conjugated diene polymers.

[0301] The amount of rubber softener in the rubber composition of this embodiment is expressed as the total amount of rubber softener added to the conjugated diene polymer and the rubbery polymer described above in advance, plus the amount of rubber softener added when forming the rubber composition.

[0302] In the rubber composition of this embodiment, the content of the rubber softener is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and even more preferably 30 to 90 parts by mass, per 100 parts by mass of the rubber component. By having a rubber softener content of 100 parts by mass or less per 100 parts by mass of the rubber component, bleed-out can be suppressed and stickiness on the surface of the rubber composition can be further suppressed.

[0303] The rubber composition of this embodiment can be produced by mixing the conjugated diene polymer of this embodiment, a rubbery polymer other than the conjugated diene polymer of this embodiment, a filler, a silane coupling agent, a rubber softener, and other additives as needed. The mixing method is not particularly limited, but examples include a melt-kneading method using a general mixer such as an open roll, Banbury mixer, kneader, single-screw extruder, twin-screw extruder, or multi-screw extruder, and a method in which the solvent is removed by heating after the components have been melt-kneaded. Of these methods, melt-kneading using a roll, Banbury mixer, kneader, or extruder is preferred from the viewpoint of productivity and good kneadability. Furthermore, the rubber components, fillers, silane coupling agents, rubber softeners, and additives may be kneaded all at once, or they may be mixed in multiple stages.

[0304] The rubber composition of this embodiment may be a vulcanized product that has been vulcanized with a vulcanizing agent. Examples of vulcanizing agents, but not limited to the following, include radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and high molecular weight polysulfur compounds.

[0305] In the rubber composition of this embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component. A conventionally known method can be used as the vulcanization method. Furthermore, the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.

[0306] When vulcanizing a rubber composition, a vulcanization accelerator and / or vulcanization aid may be used as needed. Conventional known materials can be used as vulcanization accelerators, and are not limited to the following, but examples include sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Furthermore, examples of vulcanization aids include, but are not limited to, zinc oxide and stearic acid. The content of the vulcanization accelerator and vulcanization aid is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component.

[0307] The rubber composition of this embodiment may contain various additives other than those described above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, as long as they do not impair the effects of this embodiment. Known softeners can be used as softeners. Fillers are not particularly limited, but examples include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants.

[0308] 〔tire〕 The tire of this embodiment contains the rubber composition of this embodiment described above. The tires of this embodiment are not limited to the following, but include various types of tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires, and the rubber composition of this embodiment can be suitably used in various parts of the tire, such as the tread, carcass, sidewall, and bead.

[0309] Furthermore, the numerical ranges described above as preferred ranges may be replaced with any combination of the values ​​listed as upper and lower limits, unless otherwise specified. [Examples]

[0310] The present invention will be described in more detail below with reference to specific examples and comparative examples, but the present invention is not limited in any way by the following examples and comparative examples. The various physical properties in the examples and comparative examples were measured by the methods described below.

[0311] In the following, the polymer before modification with the coupling modifier will be referred to as the "unmodified conjugated diene polymer," and the polymer after modification with the coupling modifier will be referred to as the "modified conjugated diene polymer." Furthermore, the term "conjugated diene polymer" is sometimes used as a general term for polymers before and after modification by coupling modifiers.

[0312] (Physical property 1) Average molecular weight measured by GPC method Unmodified and modified conjugated diene polymers were used as samples for GPC measurements using a GPC analyzer (Tosoh Corporation, product name "HLC-8320GPC") with three polystyrene gel-packed columns linked together, and a refractive index (RI) detector (Tosoh Corporation, product name "HLC8020"). Based on a calibration curve obtained using standard polystyrene, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and molecular weight distribution (Mw / Mn) were determined. The eluent used was a 5 mmol / L triethylamine-THF (tetrahydrofuran) solution. Three TSKgel SuperMultiporeHZ-H columns, manufactured by Tosoh Corporation, were connected together, and a TSKguardcolumn SuperMP(HZ)-H column, also manufactured by Tosoh Corporation, was connected before them as a guard column. 10 mg of the sample for measurement was dissolved in 10 mL of THF to prepare the measurement solution. 10 μL of the measurement solution was injected into the GPC analyzer, and measurements were taken under the conditions of an oven temperature of 40°C and a THF flow rate of 0.35 mL / min. The measured results were defined as the average molecular weight of each sample.

[0313] (Physical properties 2) Polymer Mooney viscosity Unmodified conjugated diene polymers and modified conjugated diene polymers were used as samples, and the Mooney viscosity was measured using a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) with an L-shaped rotor in accordance with ISO 289. The measurement temperature was set to 110°C when using unmodified conjugated diene polymers as samples, and to 100°C when using modified conjugated diene polymers as samples. After preheating the sample at the test temperature for 1 minute, the rotor is rotated at 2 rpm, and the torque is measured after 4 minutes to determine the Mooney viscosity (ML). (1+4) ) was measured.

[0314] (Physical property 3) Mooney relaxation rate Using unmodified and modified conjugated diene polymers as samples, a Mooney viscometer (product name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used to measure the Mooney viscosity in accordance with ISO 289 using an L-shaped rotor. Immediately after measuring, the rotor rotation was stopped, and the torque was recorded in Mooney units at 0.1-second intervals from 1.6 to 5 seconds after stopping. The slope of the line plotted on a log-log scale between torque and time (seconds) was determined, and its absolute value was defined as the Mooney relaxation rate (MSR). The measurement temperature was set to 110°C when using unmodified conjugated diene polymers as samples, and to 100°C when using modified conjugated diene polymers as samples.

[0315] (Physical properties 4, 8) Branching degree distribution curve and absolute molecular weight Using a modified conjugated diene polymer as the sample, measurements were performed using a GPC analyzer (Malvern's "GPCmax VE-2001") with three columns packed with polystyrene gel. The three detectors were connected in the following order: a light scattering detector, a radioisotope detector, and a viscosity detector (Malvern's "TDA305"). Based on standard polystyrene, the absolute molecular weight was determined from the light scattering and radioisotope detector results, and the intrinsic viscosity was determined from the radioisotope and viscosity detector results. Linear polymers have an intrinsic viscosity [η0] = 10 -3.498 M 0.711 The shrinkage factor (g') was calculated as the ratio of intrinsic viscosities corresponding to each molecular weight, following the formula above. In the above formula, M is the absolute molecular weight. The eluent used was THF containing 5 mmol / L triethylamine. The columns used were TSKgel G4000HXL, TSKgel G5000HXL, and TSKgel G6000HXL, all manufactured by Tosoh Corporation, connected together. 20 mg of the sample for measurement was dissolved in 10 mL of THF to prepare the measurement solution. 100 μL of the measurement solution was injected into a GPC analyzer, and measurements were taken under the conditions of an oven temperature of 40°C and a THF flow rate of 1 mL / min. Based on the above measurements, absolute molecular weight distribution curves and branching degree distribution curves of the modified conjugated diene polymer were obtained, and the branching degree (Bn), defined as g' = 6Bn / {(Bn+1)(Bn+2)} using the shrinkage factor (g'), was calculated. Using the peak height Hi in the absolute molecular weight distribution curve as a reference, the branching degree Bn(high) of the conjugated diene copolymer at the highest absolute molecular weight Mw(high) among at least two absolute molecular weights when the height in the absolute molecular weight distribution curve is half the height of Hi (1 / 2Hi), the branching degree Bn(low) of the conjugated diene copolymer at the lowest absolute molecular weight Mw(low), and the branching degree Bn_top of the conjugated diene copolymer at the peak top of the absolute molecular weight distribution curve were determined. Furthermore, (Bn(high))-(Bn(top)), (Bn(low))-(Bn(top)), and (Bn(high)) / (Bn(low)) were calculated.

[0316] (Physical property 5) Degeneration rate The denaturation rates of the polymer before modification with the coupling denaturing agent (conjugated diene polymer) and the polymer after modification with the coupling denaturing agent (modified conjugated diene polymer) were measured by column adsorption GPC as follows. The column adsorption GPC method is a method for determining the modification rate of a modified polymer by utilizing the property that modified basic polymer components in modified conjugated diene polymers are easily adsorbed onto a GPC column packed with silica gel. Each polymer was used as a sample, and the sample solution containing the sample and a low molecular weight internal standard polystyrene was measured using a polystyrene column. Furthermore, the same sample solution was measured using a silica-based column. The amount of adsorption onto the silica column was measured and the denaturation rate determined by calculating the difference between the chromatogram obtained using a polystyrene column and the chromatogram obtained using a silica column.

[0317] <Preparation of sample solution>: A sample solution was prepared by dissolving 10 mg of the sample and 5 mg of standard polystyrene in 10 mL of THF. The modification rate of conjugated diene polymers and modified conjugated diene polymers was measured under the following measurement conditions.

[0318] <GPC measurement conditions using polystyrene columns> GPC measurements were performed using the "HLC-8320GPC" product (manufactured by Tosoh Corporation) and an RI detector ("HLC8020" product (manufactured by Tosoh Corporation)). A 5 mmol / L triethylamine-THF solution was used as the eluent, and 10 μL of the sample solution was injected into the GPC instrument. A chromatogram was obtained under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.35 mL / min. The column consisted of three "TSKgel SuperMultiporeHZ-H" columns manufactured by Tosoh Corporation, with a "TSKguardcolumn SuperMP(HZ)-H" column, also manufactured by Tosoh Corporation, connected before them as a guard column.

[0319] <GPC measurement conditions using silica-based columns> GPC measurements were performed using the "HLC-8320GPC" product (manufactured by Tosoh Corporation) and an RI detector ("HLC8020" product (manufactured by Tosoh Corporation)). Using THF as the eluent, 50 μL of the sample solution was injected into the apparatus, and a chromatogram was obtained under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml / min. The columns used were Agilent's "Zorbax PSM-1000S," "PSM-300S," and "PSM-60S," connected in that order, with a "DIOL 4.6×12.5mm 5micron" column connected before them as a guard column.

[0320] How to calculate the rate of degeneration: For chromatograms obtained using polystyrene columns, the peak area P1 of the sample and the peak area P2 of standard polystyrene were determined, with the total peak area set to 100. Similarly, for chromatograms obtained using silica columns, the peak area P3 of the sample and the peak area P4 of standard polystyrene were determined, with the total peak area set to 100. The denaturation rate (mass%) was calculated using the following formula. Degeneration rate (mass%) = [1 - (P2 × P3) / (P1 × P4)] × 100 (However, P1+P2=P3+P4=100)

[0321] (Physical property 6) Amount of bonded vinyl aromatic monomer units (amount of bonded styrene) A modified conjugated diene polymer was used as the sample; 100 mg of the sample was dissolved in 100 mL of chloroform to prepare the sample for measurement. Each sample was measured using a spectrophotometer (Shimadzu Corporation, product name "UV-2450"), and the absorption spectrum was obtained. From the absorbance of ultraviolet light (around 254 nm) originating from the phenyl group of styrene, the amount of bound styrene (mass%) relative to 100% by mass of the modified conjugated diene polymer was calculated.

[0322] (Physical property 7) Amount of vinyl bonds in bonded conjugated dienes (Amount of 1,2-vinyl bonds in bonded butadiene) A modified conjugated diene polymer was used as the sample. 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare the sample for measurement. The infrared spectrum of each sample was measured at 600-1000 cm². -1 Measurements were taken within this range using a Fourier transform infrared spectrophotometer (product name "FT-IR230" manufactured by JASCO Corporation). The amount of 1,2-vinyl bonded material (mol%) in the bound butadiene was determined from the absorbance at a given wavenumber, following Hampton's method (as described in RRHampton, Analytical Chemistry 21,923 (1949)).

[0323] (Physical property 9) Glass transition temperature (glass transition point) Modified conjugated diene polymers were used as samples, and differential scanning calorimeter (DSC3200S, manufactured by MacScience) was used to perform DSC measurements in accordance with ISO 22768:2006. Under a helium flow of 50 mL / min, the DSC curve was recorded while increasing the temperature from -100°C at 20°C / min, and the peak top (inflection point) of the DSC differential curve was defined as the glass transition temperature.

[0324] (Example 1) Modified conjugated diene polymer (A1) Two tank-type pressure vessels, each with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L / D) of 4.0, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a jacket for temperature control, were connected together as polymerization branching reactors. 1,3-butadiene, styrene, and n-hexane, from which water had been removed beforehand, were continuously supplied to the bottom of the first reactor at rates of 18.5 g / min, 6.2 g / min, and 117.4 g / min, respectively, while being mixed. Immediately before the mixed solution entered the first reactor, n-butyllithium was continuously added at a rate of 0.096 mmol / min using a static mixer to deactivate any remaining impurities. Simultaneously with the supply of 1,3-butadiene, styrene, n-hexane, and n-butyllithium, 2,2-bis(2-oxolanil)propane as a polar compound and n-butyllithium (indicated as "d-1" in Table 1) as a polymerization initiator were supplied to the bottom of the first reactor at rates of 0.049 mmol / min and 0.202 mmol / min, respectively, while the reaction solution was vigorously stirred with a stirrer. The temperature inside the first reactor was maintained at 82°C.

[0325] The conjugated diene polymer solution produced by the polymerization reaction in the first reactor was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor. Once the polymerization was sufficiently stable, trimethoxy(4-vinylphenyl)silane (indicated as "c-1" in Table 1) was supplied from the bottom of the second reactor at a rate of 0.006 mmol / min as a branching agent, and an additional 1,3-butadiene was added at a rate of 6.2 g / min to carry out the polymerization branching step. The temperature inside the second reactor was maintained at 86°C. A small amount of the conjugated diene polymer solution was withdrawn from the outlet of the second reactor, and antioxidant (BHT) was added so that the antioxidant content was 0.2 g per 100 g of conjugated diene polymer, after which the solvent was removed. The obtained conjugated diene polymer was measured for various molecular weights by GPC, as well as for Mooney viscosity and Mooney relaxation rate at 110°C. The physical properties are shown in Table 1 (Physical Properties 1-1, 1-2, 1-3, Physical Properties 2, Physical Properties 3).

[0326] Next, the conjugated diene polymer solution that flowed out from the top of the second reactor was supplied to a static mixer. Furthermore, the conjugated diene polymer was coupled to the conjugated diene polymer solution flowing continuously through the static mixer by continuously adding 1-methyl-4-(3-(trimethoxysilyl)propyl)piperazine (indicated as "a-1" in Table 1) at a rate of 0.104 mmol / min and tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (indicated as "b-1" in Table 1) at a rate of 0.003 mmol / min as coupling modifiers. At this time, the time until the coupling modifier was added to the polymer solution flowing out from the outlet of the second reactor was 4.8 minutes, and the temperature of the polymer solution at the time of addition of the coupling modifier was 68°C. In addition, the difference between the temperature of the polymer solution at the outlet of the second reactor and the temperature of the polymer solution when the coupling modifier was added was 2°C.

[0327] Next, to the polymer solution effluent from the static mixer, an n-hexane solution of antioxidant (BHT) was continuously added at a rate of 0.055 g / min, so that the antioxidant (BHT) content was 0.2 g per 100 g of polymer, thereby terminating the coupling reaction. The solvent was removed by steam stripping, and the mixture was formed into a veil to obtain the modified conjugated diene polymer (A1). Various physical properties of the obtained modified conjugated diene polymer (A1) were measured. The measurement results are shown in Table 1.

[0328] (Example 2) Modified conjugated diene polymer (A2) A modified conjugated diene polymer (A2) was obtained in the same manner as in Example 1, except that c-1 as a branching agent was supplied at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers were supplied at 0.093 mmol / min and 0.006 mmol / min, respectively. Table 1 shows the properties of each modified conjugated diene polymer (A2).

[0329] (Example 3) Modified conjugated diene polymer (A3) A modified conjugated diene polymer (A3) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively. Table 1 shows the properties of each modified conjugated diene polymer (A3).

[0330] (Example 4) Modified conjugated diene polymer (A4) A modified conjugated diene polymer (A4) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.066 mmol / min and 0.011 mmol / min, respectively. Table 1 shows the properties of each modified conjugated diene polymer (A4).

[0331] (Example 5) Modified conjugated diene polymer (A5) A modified conjugated diene polymer (A5) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.056 mmol / min and 0.014 mmol / min, respectively. Table 1 shows the properties of each modified conjugated diene polymer (A5).

[0332] (Example 6) Modified conjugated diene polymer (A6) A modified conjugated diene polymer (A6) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.033 mmol / min and 0.019 mmol / min, respectively. Table 1 shows the properties of each modified conjugated diene polymer (A6).

[0333] (Example 7) Modified conjugated diene polymer (A7) A modified conjugated diene polymer (A7) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.173 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, c-1 as a branching agent at 0.010 mmol / min, and a-1 and b-1 as coupling modifiers at 0.071 mmol / min and 0.007 mmol / min, respectively. Table 2 shows the properties of the modified conjugated diene polymer (A7).

[0334] (Example 8) Modified conjugated diene polymer (A8) A modified conjugated diene polymer (A8) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.221 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.054 mmol / min, c-1 as a branching agent at 0.012 mmol / min, and a-1 and b-1 as coupling modifiers at 0.088 mmol / min and 0.009 mmol / min, respectively. Table 2 shows the properties of the modified conjugated diene polymer (A8).

[0335] (Example 9) Modified conjugated diene polymer (A9) A modified conjugated diene polymer (A8) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.022 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively. Table 2 shows the properties of each modified conjugated diene polymer (A9).

[0336] (Example 10) Modified conjugated diene polymer (A10) A modified conjugated diene polymer (A10) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.022 mmol / min, and a-1 and b-1 as coupling modifiers at 0.033 mmol / min and 0.019 mmol / min, respectively. Table 2 shows the properties of the modified conjugated diene polymer (A10).

[0337] (Example 11) Modified conjugated diene polymer (A11) A modified conjugated diene polymer (A11) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.054 mmol / min and 0.006 mmol / min, respectively. Table 2 shows the properties of the modified conjugated diene polymer (A11).

[0338] (Example 12) Modified conjugated diene polymer (A12) Two connected tank-type pressure vessels were modified to have an internal volume of 15L and an internal height (L) to diameter (D) ratio (L / D) of 6.0. The mixture was infused with 10.4 g / min of 1,3-butadiene, 4.0 g / min of styrene, 66.9 g / min of n-hexane, 0.062 mmol / min of n-butyllithium for impurity treatment, 0.125 mmol / min of d-1 as a polymerization initiator, and 2,2-bis(2-oxolanil)p as a polar compound. A modified conjugated diene polymer (A12) was obtained in the same manner as in Example 1, except that 0.031 mmol / min of ropane, 5.6 g / min of additional 1,3-butadiene, 0.007 mmol / min of c-1 as a branching agent, and 0.057 mmol / min and 0.004 mmol / min of a-1 and b-1 as coupling modifiers, respectively, were supplied, the temperature of the first reactor was set to 68°C, and the temperature of the second reactor was set to 86°C. The properties of the modified conjugated diene polymer (A12) are shown in Table 2.

[0339] (Example 13) Modified conjugated diene polymer (A13) A modified conjugated diene polymer (A13) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (indicated as "b-2" in the table) as coupling modifiers at 0.077 mmol / min and 0.016 mmol / min, respectively. Table 3 shows the properties of the modified conjugated diene polymer (A13).

[0340] (Example 14) Modified conjugated diene polymer (A14) A modified conjugated diene polymer (A14) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 19.7 g / min, styrene at 4.6 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.080 mmol / min, additional 1,3-butadiene at 6.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.100 mmol / min and 0.003 mmol / min, respectively, and the temperature of the first reactor was set to 75°C and the temperature of the second reactor to 80°C. The properties of the modified conjugated diene polymer (A14) are shown in Table 3.

[0341] (Example 15) Modified conjugated diene polymer (A15) A modified conjugated diene polymer (A15) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 19.7 g / min, styrene at 4.6 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.080 mmol / min, additional 1,3-butadiene at 6.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.089 mmol / min and 0.005 mmol / min, respectively, and the temperature of the first reactor was set to 75°C and the temperature of the second reactor to 80°C. The properties of the modified conjugated diene polymer (A15) are shown in Table 3.

[0342] (Example 16) Modified conjugated diene polymer (A16) A modified conjugated diene polymer (A16) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 19.7 g / min, styrene at 4.6 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.080 mmol / min, additional 1,3-butadiene at 6.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor was set to 75°C and the temperature of the second reactor to 80°C. The properties of the modified conjugated diene polymer (A16) are shown in Table 3.

[0343] (Example 17) Modified conjugated diene polymer (A17) A modified conjugated diene polymer (A17) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 19.7 g / min, styrene at 4.6 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.080 mmol / min, additional 1,3-butadiene at 6.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.066 mmol / min and 0.011 mmol / min, respectively, and the temperature of the first reactor was set to 75°C and the temperature of the second reactor to 80°C. The properties of the modified conjugated diene polymer (A17) are shown in Table 3.

[0344] (Example 18) Modified conjugated diene polymer (A18) A modified conjugated diene polymer (A18) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 19.7 g / min, styrene at 4.6 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.080 mmol / min, additional 1,3-butadiene at 6.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.056 mmol / min and 0.014 mmol / min, respectively, and the temperature of the first reactor was set to 75°C and the temperature of the second reactor to 80°C. The properties of the modified conjugated diene polymer (A18) are shown in Table 3.

[0345] (Example 19) Modified conjugated diene polymer (A19) A modified conjugated diene polymer (A19) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.104 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.100 mmol / min and 0.003 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A19) are shown in Table 4.

[0346] (Example 20) Modified conjugated diene polymer (A20) A modified conjugated diene polymer (A20) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.104 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.089 mmol / min and 0.005 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A20) are shown in Table 4.

[0347] (Example 21) Modified conjugated diene polymer (A21) A modified conjugated diene polymer (A21) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.104 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A21) are shown in Table 4.

[0348] (Example 22) Modified conjugated diene polymer (A22) A modified conjugated diene polymer (A22) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.104 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.066 mmol / min and 0.011 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A22) are shown in Table 4.

[0349] (Example 23) Modified conjugated diene polymer (A23) A modified conjugated diene polymer (A23) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.104 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.056 mmol / min and 0.014 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A23) are shown in Table 4.

[0350] (Example 24) Modified conjugated diene polymer (A24) A modified conjugated diene polymer (A24) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at a rate of 16.2 g / min, styrene at a rate of 9.2 g / min, 2,2-bis(2-oxolanyl)propane as a polar compound at a rate of 0.045 mmol / min, additional 1,3-butadiene at a rate of 5.4 g / min, and c-1 as a branching agent at a rate of 0.011 mmol / min, the temperature of the first reactor was set to 83°C and the temperature of the second reactor was set to 88°C. The properties of the modified conjugated diene polymer (A24) are shown in Table 4.

[0351] (Example 25) Modified conjugated diene polymer (A25) A modified conjugated diene polymer (A25) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 16.2 g / min, styrene at 9.2 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, additional 1,3-butadiene at 5.4 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.093 mmol / min and 0.006 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A25) are shown in Table 5.

[0352] (Example 26) Modified conjugated diene polymer (A26) A modified conjugated diene polymer (A26) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 16.2 g / min, styrene at 9.2 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, additional 1,3-butadiene at 5.4 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.081 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A26) are shown in Table 5.

[0353] (Example 27) Modified conjugated diene polymer (A27) A modified conjugated diene polymer (A27) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 16.2 g / min, styrene at 9.2 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, additional 1,3-butadiene at 5.4 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.070 mmol / min and 0.011 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A27) are shown in Table 5.

[0354] (Example 28) Modified conjugated diene polymer (A28) A modified conjugated diene polymer (A28) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 16.2 g / min, styrene at 9.2 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, additional 1,3-butadiene at 5.4 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.058 mmol / min and 0.014 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A28) are shown in Table 5.

[0355] (Example 29) Modified conjugated diene polymer (A29) A modified conjugated diene polymer (A29) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.2 g / min, styrene at 7.9 g / min, d-1 as a polymerization initiator at 0.197 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.060 mmol / min, additional 1,3-butadiene at 5.7 g / min, c-1 as a branching agent at 0.024 mmol / min, and a-1 and b-1 as coupling modifiers at 0.091 mmol / min and 0.003 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 78°C. The properties of the modified conjugated diene polymer (A29) are shown in Table 5.

[0356] (Example 30) Modified conjugated diene polymer (A30) A modified conjugated diene polymer (A30) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.2 g / min, styrene at 7.9 g / min, d-1 as a polymerization initiator at 0.197 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.060 mmol / min, additional 1,3-butadiene at 5.7 g / min, c-1 as a branching agent at 0.024 mmol / min, and a-1 and b-1 as coupling modifiers at 0.082 mmol / min and 0.005 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 78°C. The properties of the modified conjugated diene polymer (A30) are shown in Table 5.

[0357] (Example 31) Modified conjugated diene polymer (A31) A modified conjugated diene polymer (A31) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.2 g / min, styrene at 7.9 g / min, d-1 as a polymerization initiator at 0.197 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.060 mmol / min, additional 1,3-butadiene at 5.7 g / min, c-1 as a branching agent at 0.024 mmol / min, and a-1 and b-1 as coupling modifiers at 0.073 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 78°C. The properties of the modified conjugated diene polymer (A31) are shown in Table 6.

[0358] (Example 32) Modified conjugated diene polymer (A32) A modified conjugated diene polymer (A32) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.2 g / min, styrene at 7.9 g / min, d-1 as a polymerization initiator at 0.197 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.060 mmol / min, additional 1,3-butadiene at 5.7 g / min, c-1 as a branching agent at 0.024 mmol / min, and a-1 and b-1 as coupling modifiers at 0.062 mmol / min and 0.010 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 78°C. The properties of the modified conjugated diene polymer (A32) are shown in Table 6.

[0359] (Example 33) Modified conjugated diene polymer (A33) A modified conjugated diene polymer (A33) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 17.2 g / min, styrene at 7.9 g / min, d-1 as a polymerization initiator at 0.197 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.060 mmol / min, additional 1,3-butadiene at 5.7 g / min, c-1 as a branching agent at 0.024 mmol / min, and a-1 and b-1 as coupling modifiers at 0.051 mmol / min and 0.013 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 78°C. The properties of the modified conjugated diene polymer (A33) are shown in Table 6.

[0360] (Example 34) Modified conjugated diene polymer (A34) A modified conjugated diene polymer (A34) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.032 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.105 mmol / min and 0.003 mmol / min, respectively, and the temperature of the first reactor was set to 82°C and the temperature of the second reactor to 86°C. The properties of the modified conjugated diene polymer (A34) are shown in Table 6.

[0361] (Example 35) Modified conjugated diene polymer (A35) A modified conjugated diene polymer (A35) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.032 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.094 mmol / min and 0.006 mmol / min, respectively, and the temperature of the first reactor was set to 82°C and the temperature of the second reactor to 86°C. The properties of the modified conjugated diene polymer (A35) are shown in Table 6.

[0362] (Example 36) Modified conjugated diene polymer (A36) A modified conjugated diene polymer (A36) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.032 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.083 mmol / min and 0.009 mmol / min, respectively, and the temperature of the first reactor was set to 82°C and the temperature of the second reactor to 86°C. The properties of the modified conjugated diene polymer (A36) are shown in Table 6.

[0363] (Example 37) Modified conjugated diene polymer (A37) A modified conjugated diene polymer (A37) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.032 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.070 mmol / min and 0.012 mmol / min, respectively, and the temperature of the first reactor was set to 82°C and the temperature of the second reactor to 86°C. The properties of the modified conjugated diene polymer (A37) are shown in Table 7.

[0364] (Example 38) Modified conjugated diene polymer (A38) A modified conjugated diene polymer (A38) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 20.8 g / min, styrene at 3.1 g / min, d-1 as a polymerization initiator at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.032 mmol / min, additional 1,3-butadiene at 6.9 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.058 mmol / min and 0.014 mmol / min, respectively, and the temperature of the first reactor was set to 82°C and the temperature of the second reactor to 86°C. The properties of the modified conjugated diene polymer (A38) are shown in Table 7.

[0365] (Example 39) Modified conjugated diene polymer (A39) A modified conjugated diene polymer (A39) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.028 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.105 mmol / min and 0.003 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The physical properties of the modified conjugated diene polymer (A39) are shown in Table 7.

[0366] (Example 40) Modified conjugated diene polymer (A40) A modified conjugated diene polymer (A40) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.028 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.093 mmol / min and 0.006 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A40) are shown in Table 7.

[0367] (Example 41) Modified conjugated diene polymer (A41) A modified conjugated diene polymer (A41) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.028 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.081 mmol / min and 0.009 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The physical properties of the modified conjugated diene polymer (A41) are shown in Table 7.

[0368] (Example 42) Modified conjugated diene polymer (A42) A modified conjugated diene polymer (A42) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.028 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.070 mmol / min and 0.012 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A42) are shown in Table 7.

[0369] (Example 43) Modified conjugated diene polymer (A43) A modified conjugated diene polymer (A43) was obtained in the same manner as in Example 1, except that d-1 as a polymerization initiator was supplied at 0.207 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.028 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.060 mmol / min and 0.014 mmol / min, respectively, and the temperature of the first reactor was set to 83°C and the temperature of the second reactor to 88°C. The properties of the modified conjugated diene polymer (A43) are shown in Table 8.

[0370] (Example 44) Modified conjugated diene polymer (A44) A modified conjugated diene polymer (A44) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 15.0 g / min, styrene at 10.8 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.092 mmol / min, additional 1,3-butadiene at 5.0 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A44) are shown in Table 8.

[0371] (Example 45) Modified conjugated diene polymer (A45) A modified conjugated diene polymer (A45) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 14.3 g / min, styrene at 11.7 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.100 mmol / min, additional 1,3-butadiene at 4.8 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 82°C. The properties of the modified conjugated diene polymer (A45) are shown in Table 8.

[0372] (Example 46) Modified conjugated diene polymer (A46) A modified conjugated diene polymer (A46) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 13.9 g / min, styrene at 12.3 g / min, d-1 as a polymerization initiator at 0.193 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.092 mmol / min, additional 1,3-butadiene at 4.6 g / min, c-1 as a branching agent at 0.011 mmol / min, and a-1 and b-1 as coupling modifiers at 0.077 mmol / min and 0.008 mmol / min, respectively, and the temperature of the first reactor was set to 68°C and the temperature of the second reactor to 74°C. The properties of the modified conjugated diene polymer (A46) are shown in Table 8.

[0373] (Example 47) Modified conjugated diene polymer (A47) A modified conjugated diene polymer (A47) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 24.1 g / min, styrene at 0 g / min, n-hexane at 134.7 g / min, n-butyllithium for impurity treatment at 0.076 mmol / min, d-1 as a polymerization initiator at 0.245 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.009 mmol / min, additional 1,3-butadiene at 0 g / min, c-1 as a branching agent at 0.014 mmol / min, and a-1 and b-1 as coupling modifiers at 0.094 mmol / min and 0.010 mmol / min, respectively, and the temperature of the first reactor and the second reactor were set to 76°C. The properties of the modified conjugated diene polymer (A47) are shown in Table 8.

[0374] (Example 48) Modified conjugated diene polymer (A48) A modified conjugated diene polymer (A48) was obtained in the same manner as in Example 1, except that d-1 was supplied as a polymerization initiator at 0.193 mmol / min, c-1 as a branching agent at 0.011 mmol / min, and trimethoxy(propyl)silane (referred to as "a-2" in Table 1) at 0.077 mmol / min and 1,6-bis(trimethoxysilyl)hexane (referred to as "b-3" in Table 1) at 0.016 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A48) are shown in Table 8.

[0375] (Example 49) Modified conjugated diene polymer (A49) A modified conjugated diene polymer (A49) was obtained in the same manner as in Example 1, except that d-1 was supplied at 0.193 mmol / min as a polymerization initiator, c-1 at 0.011 mmol / min as a branching agent, and N-benzylidene-3-(trimethoxysilyl)propan-1-amine (referred to as "a-3" in Table 1) at 0.052 mmol / min and b-1 at 0.008 mmol / min as coupling modifiers. The properties of the modified conjugated diene polymer (A49) are shown in Table 9.

[0376] (Example 50) Modified conjugated diene polymer (A50) A modified conjugated diene polymer (A50) was obtained in the same manner as in Example 1, except that two connected tank-type pressure vessels were modified to have an internal volume of 15 L and an internal height (L) to diameter (D) ratio (L / D) of 6.0, d-1 as a polymerization initiator was supplied at 0.193 mmol / min, n-hexane at 91.0 mmol / min, and a-1 and b-1 as coupling modifiers at 0.089 mmol / min and 0.005 mmol / min, respectively, the temperature of the first reactor was set to 68°C and the temperature of the second reactor was set to 86°C. The various properties of the modified conjugated diene polymer (A50) are shown in Table 9.

[0377] (Example 51) Modified conjugated diene polymer (A51) A modified conjugated diene polymer (A51) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 22.0 g / min, styrene at 1.5 g / min, d-1 as a polymerization initiator at 0.212 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.054 mmol / min, additional 1,3-butadiene at 7.3 g / min, c-1 as a branching agent at 0.012 mmol / min, and a-1 and b-1 as coupling modifiers at 0.084 mmol / min and 0.009 mmol / min, respectively. The properties of the modified conjugated diene polymer (A51) are shown in Table 9.

[0378] (Example 52) Modified conjugated diene polymer (A52) A modified conjugated diene polymer (A52) was obtained in the same manner as in Example 1, except that 1,3-butadiene was supplied at 22.0 g / min, styrene at 1.5 g / min, d-1 as a polymerization initiator at 0.212 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.043 mmol / min, additional 1,3-butadiene at 7.3 g / min, c-1 as a branching agent at 0.012 mmol / min, and a-1 and b-1 as coupling modifiers at 0.084 mmol / min and 0.009 mmol / min, respectively. The properties of the modified conjugated diene polymer (A52) are shown in Table 9.

[0379] (Example 53) Modified conjugated diene polymer (A53) 1,3-butadiene at 20.8 g / min, styrene at 3.1 g / min, a mixed solution of prepared piperidinolithium (also called "1-lithiopiperidine") and n-butyllithium (with a molar ratio of piperidinolithium to n-butyllithium of 0.75:0.25; abbreviated as "d-2" in the table) at 0.193 mmol / min, and 2,2-bis(2-oxolanil)propane as a polar compound. A modified conjugated diene polymer (A53) was obtained in the same manner as in Example 1, except that 0.054 mmol / min of 1,3-butadiene was supplied, an additional 6.9 g / min of 1,3-butadiene, 0.011 mmol / min of c-1 as a branching agent, and 0.077 mmol / min and 0.008 mmol / min of a-1 and b-1 as coupling modifiers, respectively, were supplied, the temperature of the first reactor was set to 56°C, and the temperature of the second reactor was set to 66°C. The physical properties of the modified conjugated diene polymer (A53) are shown in Table 9.

[0380] (Comparative Example 1) Modified conjugated diene polymer (B1) Two tank-type pressure vessels, each with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L / D) of 4.0, an inlet at the bottom, an outlet at the top, and equipped with a stirrer and a jacket for temperature control, were connected together as polymerization branching reactors. 1,3-butadiene, styrene, and n-hexane, from which water had been removed beforehand, were continuously supplied to the bottom of the first reactor while being mixed at rates of 18.5 g / min, 6.2 g / min, and 138.9 g / min, respectively. Immediately before the mixed solution entered the first reactor, n-butyllithium was continuously added at a rate of 0.096 mmol / min using a static mixer to inactivate any remaining impurities. Simultaneously with the supply of 1,3-butadiene, styrene, n-hexane, and n-butyllithium, 2,2-bis(2-oxolanil)propane as a polar compound and n-butyllithium as a polymerization initiator were supplied to the bottom of the first reactor at rates of 0.049 mmol / min and 0.193 mmol / min, respectively, while the reaction solution was vigorously stirred with a stirrer. The temperature inside the first reactor was maintained at 82°C.

[0381] The conjugated diene polymer solution produced by the polymerization reaction in the first reactor was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor. Once the polymerization was sufficiently stable, trimethoxy(4-vinylphenyl)silane (referred to as "c-1" in Table 10) was supplied from the bottom of the second reactor at a rate of 0.011 mmol / min as a branching agent, and an additional 1,3-butadiene was added at a rate of 6.2 g / min to carry out the polymerization branching step. The temperature inside the second reactor was maintained at 86°C. A small amount of the conjugated diene polymer solution was withdrawn from the outlet of the second reactor, and antioxidant (BHT) was added so that the antioxidant content was 0.2 g per 100 g of conjugated diene polymer, after which the solvent was removed. The obtained conjugated diene polymer was measured for various molecular weights by GPC, as well as for Mooney viscosity at 110°C and Mooney relaxation rate. The physical properties are shown in Table 10 (Physical Properties 1-1, 1-2, 1-3, Physical Properties 2, Physical Properties 3).

[0382] Next, the conjugated diene polymer solution that flowed out from the top of the second reactor was supplied to a static mixer. Furthermore, the conjugated diene polymer was coupled to the conjugated diene polymer solution flowing continuously through the static mixer by continuously adding b-1 as a coupling modifier at a rate of 0.028 mmol / min. At this time, the time from when the coupling modifier was added to the polymer solution flowing out from the outlet of the second reactor was 4.8 minutes, and the temperature of the polymer solution at the time of addition of the coupling modifier was 68°C. In addition, the difference between the temperature of the polymer solution at the outlet of the second reactor and the temperature of the polymer solution at the time of addition of the coupling modifier was 2°C.

[0383] Next, to the polymer solution discharged from the static mixer, an n-hexane solution of antioxidant (BHT) was continuously added at a rate of 0.055 g / min, so that the antioxidant (BHT) content was 0.2 g per 100 g of polymer, thereby terminating the coupling reaction. The solvent was removed by steam stripping, and the mixture was formed into a veil to obtain the modified conjugated diene polymer (B1). Various physical properties of the obtained modified conjugated diene polymer (B1) were measured. The measurement results are shown in Table 10.

[0384] (Comparative Example 2) Modified conjugated diene polymer (B2) A modified conjugated diene polymer (B2) was obtained in the same manner as in Comparative Example 1, except that n-hexane was supplied at 117.4 mmol / min, c-1 as a branching agent was omitted, and a-1 and b-1 as coupling modifiers were supplied at 0.077 mmol / min and 0.008 mmol / min, respectively. The physical properties of the modified conjugated diene polymer (B2) are shown in Table 10.

[0385] (Comparative Example 3) Modified conjugated diene polymer (B3) A modified conjugated diene polymer (B3) was obtained in the same manner as in Comparative Example 1, except that n-butyllithium was supplied as a polymerization initiator at 0.144 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.038 mmol / min, c-1 as a branching agent at 0.009 mmol / min, and a-1 and b-1 as coupling modifiers at 0.061 mmol / min and 0.006 mmol / min, respectively. The properties of the modified conjugated diene polymer (B3) are shown in Table 10.

[0386] (Comparative Example 4) Modified conjugated diene polymer (B4) A modified conjugated diene polymer (B4) was obtained in the same manner as in Comparative Example 1, except that n-butyllithium was supplied as a polymerization initiator at 0.221 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.054 mmol / min, c-1 as a branching agent at 0.025 mmol / min, and a-1 and b-1 as coupling modifiers at 0.032 mmol / min and 0.019 mmol / min, respectively. The physical properties of the modified conjugated diene polymer (B4) are shown in Table 10.

[0387] (Comparative Example 5) Modified conjugated diene polymer (B5) A modified conjugated diene polymer (B5) was obtained in the same manner as in Comparative Example 1, except that 1,3-butadiene was supplied at 16.2 g / min, styrene at 9.2 g / min, n-butyllithium as a polymerization initiator at 0.202 mmol / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.045 mmol / min, an additional 1,3-butadiene at 5.4 g / min, and b-1 was supplied at 0.028 mmol / min without the addition of a-1 as a coupling modifier. The properties of the modified conjugated diene polymer (B5) are shown in Table 10.

[0388] (Comparative Example 6) Modified conjugated diene polymer (B6) A modified conjugated diene polymer (B6) was obtained in the same manner as in Comparative Example 1, except that 1,3-butadiene was supplied at 15.0 g / min, styrene at 10.8 g / min, 2,2-bis(2-oxolanil)propane as a polar compound at 0.092 mmol / min, an additional 1,3-butadiene at 5.0 g / min, and b-1 was supplied at 0.028 mmol / min without the addition of a-1 as a coupling modifier. The properties of the modified conjugated diene polymer (B6) are shown in Table 10.

[0389] [Table 1]

[0390] [Table 2]

[0391] [Table 3]

[0392] [Table 4]

[0393] [Table 5]

[0394] [Table 6]

[0395] [Table 7]

[0396] [Table 8]

[0397] [Table 9]

[0398] [Table 10]

[0399] [Evaluation of veils of modified conjugated diene polymers] (Evaluation 1) Appearance of the veil (presence or absence of cracks or crumbling) The bales of modified conjugated diene polymers produced by the methods shown in the Examples and Comparative Examples were visually observed for their appearance, including the presence or absence of external cracks and crumbling. Each panelist evaluated them based on the following criteria, with a maximum score of 4 points. The appearance of the bale is an indicator of the bale moldability of the modified conjugated diene polymer. IV: The crumbs do not come together and cannot be formed into a bale. III: Although it can be formed into a veil, it shows signs of disintegration over time. II: Cracks, crumbling, etc. are observed on the veil surface in less than 5% of areas. I: No cracks or crumbling are visible on the surface of the veil.

[0400] [Preparation and evaluation of rubber compositions] (Evaluation of rubber composition) Using the modified conjugated diene polymers A1-A53 and B1-B6 shown in Tables 1-10 as raw materials, rubber compositions were obtained according to the following formulations. • Modified conjugated diene polymer (any of A1-A53 or B1-B6): 70 parts by mass (oil excluded) • Butadiene rubber (product name "BR150" manufactured by Ube Industries): 30 parts by mass • Silica (product name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m²) 2 / g):75.0 parts by mass • Carbon black (product name "Seas KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass • Silane coupling agent (product name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass • S-RAE oil (product name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation): 32.0 parts by mass ·Zinc white: 2.5 parts by mass Stearic acid: 2.0 parts by mass • Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass ·Sulfur: 1.7 parts by mass • Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiadylsulfinamide): 1.7 parts by mass • Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass

[0401] Specifically, the above-mentioned materials were kneaded in the following manner to obtain the rubber composition. Using a sealed kneader (capacity 0.5L) equipped with a temperature control device, the first stage of kneading involved a modified conjugated diene polymer (A1-A53 or B1-B6), butadiene rubber, fillers (silica, carbon black), silane coupling agent, S-RAE oil, zinc oxide, and stearic acid, under conditions of a filling rate of 65% and a rotor rotation speed of 30-50 rpm. At this time, the temperature of the sealed kneader was controlled to obtain each rubber composition (compound) so that the discharge temperature was 155-160°C.

[0402] Next, in the second stage of mixing, the compound obtained above was cooled to room temperature, an antioxidant was added, and the mixture was kneaded again under the same conditions as the first stage of mixing to improve the dispersion of silica. In this case as well, the temperature control of the mixer was adjusted so that the discharge temperature of the compound was 155-160°C. After cooling, in the third stage of mixing, sulfur and vulcanization accelerators 1 and 2 were added and kneaded in an open roll set at 70°C. After that, the mixture was molded and vulcanized in a vulcanization press at 160°C for 20 minutes. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, the evaluation was conducted using the following method. The evaluation results are shown in Tables 11 to 20.

[0403] (Evaluation 2) Emission consistency The unvulcanized modified conjugated diene polymers produced by the methods shown in the Examples and Comparative Examples were visually observed for their cohesiveness (shape) immediately after discharge from the pressurized kneader (immediately after the completion of kneading in the first stage of pressurized kneading and discharge). Each panelist evaluated the results based on the following criteria, with a maximum score of 4 points. Cohesiveness is an indicator of the processability of the vulcanized product. IV: Less than 60% of the sheet's edges are smooth, resulting in very poor processability. III: The edges of the sheet are more than 60% but less than 80% smooth, resulting in poor processability. II: The edges of the sheet are smooth for more than 80% but less than or equal to 90%, resulting in excellent processability. I: The edges of the sheet are over 90% smooth, resulting in excellent processability.

[0404] (Rating 3, 4) Viscoelastic parameters (fuel efficiency, wet grip) Viscoelastic parameters were measured in torsion mode using the "ARES" viscoelasticity tester manufactured by Rheometrics Scientific. Each measurement value was indexed with the result for the rubber composition of Comparative Example 1 set to 100. Here, tanδ, measured at 50°C, frequency 10Hz, and strain 3%, was used as an indicator of low hysteresis loss, i.e., fuel efficiency, and the result of Comparative Example 1 was standardized to 100. A larger index indicates better fuel efficiency, and values ​​exceeding 65 were evaluated as having superior fuel efficiency. Furthermore, tanδ, measured at 0°C, frequency 10Hz, and strain 1%, was used as an index of wet grip performance, and the result of Comparative Example 1 was standardized to 100. A larger index indicates better wet grip performance, and values ​​exceeding 65 were evaluated as having superior wet grip performance.

[0405] (Rating 5, 6) Tensile strength and tensile elongation Tensile strength and tensile elongation were measured in accordance with the tensile testing method of JIS K6251. Each measured value was standardized with the result of Comparative Example 1 set to 100. Higher values ​​indicate better tensile strength and tensile elongation, and superior fracture characteristics.

[0406] (Evaluation 7) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear after 1000 rotations under a load of 44.4 N was measured in accordance with JIS K6264-2. Each measured value was standardized with the result of Comparative Example 1 set to 100. A higher value indicates better abrasion resistance, and values ​​exceeding 80 were evaluated as having superior abrasion resistance.

[0407] [Table 11]

[0408] [Table 12]

[0409] [Table 13]

[0410] [Table 14]

[0411] [Table 15]

[0412] [Table 16]

[0413] [Table 17]

[0414] [Table 18]

[0415] [Table 19]

[0416] [Table 20]

[0417] The conjugated diene polymer of the present invention exhibits excellent bale-forming properties, and its vulcanized product has been found to have an excellent balance of abrasion resistance, fracture properties, and low hysteresis loss properties.

[0418] This application is based on Japanese Patent Application No. 2022-128615, filed with the Japan Patent Office on August 12, 2022, the contents of which are incorporated herein by reference. [Industrial applicability]

[0419] The conjugated diene polymer and rubber composition of the present invention exhibit excellent moldability and processability, and their vulcanized products have an excellent balance of performance in terms of wear resistance, fracture characteristics, fuel efficiency, and low hysteresis loss. Therefore, they have industrial applicability in applications such as tires, resin modifiers, automotive interior and exterior parts, vibration-damping rubber, and footwear.

Claims

1. A conjugated diene polymer that satisfies the following conditions (i) to (iii), and which contains monomer units based on 1,3-butadiene. <Condition (i)> The Mooney viscosity measured at 100°C is between 80 and 170. <Condition (ii)> The Mooney relaxation ratio (MSR), measured at 100°C, is between 0.30 and 0.

80. <Condition (iii)> GPC-light scattering measurement with a viscosity detector revealed that the branching degree distribution curve, which shows the relationship between absolute molecular weight and branching degree (Bn), has a downward-convex extreme value.

2. The glass transition temperature is -90°C to -40°C. When the height of the peak top in the absolute molecular weight distribution curve measured by GPC-light scattering with a viscosity detector (however, if there are multiple peak tops in the absolute molecular weight distribution curve, the height of the peak top with the maximum absolute molecular weight) Hi is taken as a reference, the degree of branching of the conjugated diene polymer at the highest absolute molecular weight Mw (high) among at least two absolute molecular weights when the height in the absolute molecular weight distribution curve is half the height of Hi (1 / 2Hi) is defined as Bn (high), the degree of branching of the conjugated diene polymer at the lowest absolute molecular weight Mw (low) is defined as Bn (low), and the degree of branching of the conjugated diene polymer at the peak top of the absolute molecular weight distribution curve is defined as Bn (top), then the following conditions (I) to (III) are satisfied: The conjugated diene polymer according to claim 1. <Condition (I)> (Bn(high))-(Bn(top))≧1.0 <Condition (II)> (Bn(low))-(Bn(top))≧0.5 <Condition (III)> (Bn(high)) / (Bn(low))=1.1~2.0

3. The extreme value of the branching degree distribution curve lies in the absolute molecular weight between Mw(low) and Mw(high). The conjugated diene polymer according to claim 2.

4. The molecular weight distribution (PDI; MWD) is between 1.4 and 3.

5. The conjugated diene polymer according to claim 1.

5. In the aforementioned branching degree distribution curve, the branching degree at the extreme value is 3.0 or more and 8.0 or less. The conjugated diene polymer according to claim 1.

6. The denaturation rate is 60% by mass or more. The conjugated diene polymer according to claim 1.

7. The material has a fork-shaped portion [A] in which multiple conjugated diene polymer chains are bonded to one end of the main chain branched structure, and a single chain of another conjugated diene polymer is bonded to the other end of the main chain branched structure. Three or more branched star-shaped polymer structures to which one or more fork-shaped parts [A] are joined [B] comprises a conjugated diene polymer having The conjugated diene polymer according to claim 1.

8. A conjugated diene polymer having a fork-shaped portion [A] in which multiple conjugated diene polymer chains are bonded to one end of a main chain branched structure and a single chain of another conjugated diene polymer is bonded to the other end of the main chain branched structure, Three or more branched star-shaped polymer structures to which one or more fork-shaped parts [A] are joined A conjugated diene polymer having [B], including, The conjugated diene polymer according to claim 1.

9. 100 parts by mass of the conjugated diene polymer according to any one of claims 1 to 8, A softening agent component of less than 1 part by mass, A molded article containing the above.

10. A method for producing a conjugated diene polymer according to any one of claims 1 to 8, A step of polymerizing at least a conjugated diene compound using an organolithium compound as a polymerization initiator, The process of adding a branching agent, A step of adding two or more coupling modifiers with different coupling numbers, A method for producing a conjugated diene polymer having the following characteristics.

11. The two or more coupling modifiers mentioned above A coupling modifier comprising a coupling modifier having two or fewer alkoxysilyl groups, and a coupling modifier containing more than two alkoxysilyl groups, A method for producing a conjugated diene polymer according to claim 10.

12. 100 parts by mass of rubber component, The filler comprises 5.0 parts by mass or more and 150 parts by mass or less, The rubber component contains 10 parts by mass or more of the conjugated diene polymer described in any one of claims 1 to 8, per 100 parts by mass of the total amount of the rubber component. Rubber composition.

13. A tire containing the rubber composition described in claim 12.

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