JP2021155599A - Rubber composition and tires - Google Patents

Abstract

PROBLEM TO BE SOLVED: To have extremely excellent workability in a vulcanized product, particularly excellent wear resistance and steering stability in a vulcanized product, excellent low hysteresis loss, and sufficient for practical use. A rubber composition having a high breaking strength is obtained.
A rubber composition containing 100 parts by mass of a rubber component and 30 to 150 parts by mass of silica ^{having a nitrogen adsorption specific surface area of 180 m 2 / g or more.}
The rubber component contains 10% by mass or more of the conjugated diene polymer.
The conjugated diene polymer is
The Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less.
The Mooney relaxation rate measured at 100 ° C. is 0.35 or less.
The degree of branching (Bn) by the GPC-light scattering method with a viscosity detector is 8 or more.
Rubber composition.
[Selection diagram] None

Description

The present invention relates to rubber compositions and tires.

Conventionally, there has been an increasing demand for fuel efficiency of automobiles, and improvement of rubber materials used for automobile tires, particularly tire treads in contact with road surfaces, has been required.
In recent years, due to the increasing demand for fuel efficiency regulations for automobiles, automobiles have tended to be lighter due to resinification of parts, and there is an increasing demand for thinner tire parts from the viewpoint of weight reduction.

In order to reduce the weight of a tire, it is necessary to reduce the thickness of the tread portion in contact with the road surface having a particularly high material ratio, and in the tread portion, a rubber material having better wear resistance than before is required. There is.
Further, in order to reduce the energy loss due to the tire during traveling, the rubber material used for the tire tread is required to have a small rolling resistance, that is, a material having a low hysteresis loss property.
On the other hand, from the viewpoint of safety, it is required to have excellent steering stability, wet skid resistance, and practically sufficient breaking strength.

Examples of the rubber material that meets the above-mentioned requirements include a rubber composition containing a rubber-like polymer and a reinforcing filler such as carbon black and silica.
The use of a rubber composition containing silica improves the balance between low hysteresis loss and wet skid resistance. Further, by introducing a functional group having affinity or reactivity with silica into the molecular terminal portion of the highly motility rubber-like polymer, the dispersibility of silica in the rubber composition is improved, and further, the dispersibility of silica in the rubber composition is improved. Bonding with silica particles reduces the mobility of the molecular ends of the rubber-like polymer, reducing hysteresis loss, improving wear resistance, and improving breaking strength.

For example, Patent Documents 1 to 3 propose a rubber composition of a modified conjugated diene polymer obtained by reacting an amino group-containing alkoxysilanes with an active terminal of the conjugated diene polymer and silica. There is.
Further, Patent Document 4 proposes a modified conjugated diene-based polymer obtained by coupling a polymer active terminal with a polyfunctional silane compound.

However, if the dispersibility of silica in the rubber composition is improved in order to reduce the hysteresis loss, there is a problem that the rigidity of the rubber composition is lowered and the steering stability when the tire is used is deteriorated. There is. As a means for increasing the rigidity of the rubber composition, Patent Document 5 proposes a technique of using silica having a large specific surface area and a fine particle size as a filler. However, the fine particle size silica has poor processability and is a rubber composition. There is a problem that the dispersibility in the inside tends to be poor and the low hysteresis loss property is deteriorated.

Japanese Unexamined Patent Publication No. 2005-290355 Japanese Unexamined Patent Publication No. 11-189616 Japanese Unexamined Patent Publication No. 2003-171418 International Publication No. 07/114203 Pamphlet International Publication No. 12/073837

Therefore, in the present invention, it is extremely excellent in processability when it is made into a vulcanized product, has excellent wear resistance and steering stability when it is made into a vulcanized product, is excellent in low hysteresis loss, and is sufficient for practical use. It is an object of the present invention to provide a rubber composition having a sufficient breaking strength.

As a result of diligent research and study to solve the above-mentioned problems of the prior art, the present inventors have a Mooney viscosity and a Mooney relaxation rate measured at 100 ° C. within a predetermined range, and a branching degree (Bn) within a specific range. It was found that a rubber composition composed of a certain conjugated diene-based copolymer is extremely excellent in processability when it is made into a vulcanized product, and is excellent in abrasion resistance, steering stability, and breaking strength when it is made into a vulcanized product. , The present invention has been completed.
That is, the present invention is as follows.

[1]
With 100 parts by mass of rubber component,
30 to 150 parts by mass of silica with a nitrogen adsorption specific surface area of 180 m ^{2 / g or more,}
Is a rubber composition containing
The rubber component contains 10% by mass or more of the conjugated diene polymer.
The conjugated diene polymer is
The Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less.
The Mooney relaxation rate measured at 100 ° C. is 0.35 or less.
The degree of branching (Bn) by the GPC-light scattering method with a viscosity detector is 8 or more.
Rubber composition.
[2]
The rubber composition according to the above [1], wherein the modification rate of the conjugated diene polymer measured by the column adsorption GPC method is 60% by mass or more.
[3]
The conjugated diene polymer has a star-shaped polymer structure with three or more branches and has a star-shaped polymer structure.
At least one branched chain having a star-shaped structure has a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, and a portion derived from the vinyl-based monomer containing the alkoxysilyl group or the halosilyl group. With a further main chain branching structure,
The rubber composition according to any one of the above [1] and [2].
[4]
The portion derived from the vinyl-based monomer containing an alkoxysilyl group or a halosilyl group is
A monomer unit based on a compound represented by the following formula (1) or (2).
The rubber composition according to the above [3], which has a branch point of a polymer chain by a monomer unit based on a compound represented by the following formula (1) or (2).

(In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in a part thereof.
R ^{2 to} R ³ each independently represent 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 a part thereof.
When there are a plurality of them, R ^{1 to} R ³ are independent of each other.
X ¹ represents an independent halogen atom.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3. )
(In the formula (2), R ^{2 to} R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, even if a part thereof has a branched structure. Good. When there are a plurality of them, R ^{2 to} R ⁵ are independent of each other.
X ^{2 to} X ³ represent independent halogen atoms.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3.
a indicates an integer of 0 to 2, b indicates an integer of 0 to 3, and c indicates an integer of 0 to 3. (A + b + c) indicates 3. )

[5]
The rubber composition according to the above [4], wherein in the formula (1), R ¹ is a hydrogen atom and m = 0, and has a monomer unit based on the compound represented by the formula (1). ..
[6]
The rubber composition according to the above [4], which has a monomer unit based on the compound represented by the formula (2), in which m = 0 and b = 0 in the formula (2).
[7]
In the formula (1), a ^{monomer unit based on the compound represented by the formula (1), in which R 1} is a hydrogen atom, m = 0, l = 0, and n = 3, is used. The rubber composition according to the above [4].
[8]
In the formula (2), m = 0, l = 0, n = 3, a = 0, b = 0, and c = 3, represented by the formula (2). The rubber composition according to the above [4], which has a monomer unit based on the compound to be used.
[9]
A tire containing the rubber composition according to any one of the above [1] to [8].

According to the present invention, when it is made into a vulcanized product, it has extremely excellent workability, when it is made into a vulcanized product, it has particularly excellent wear resistance and steering stability, and it is excellent in low hysteresis loss. A rubber composition having practically sufficient breaking strength can be obtained.

Hereinafter, embodiments for carrying out the present invention (hereinafter, referred to as “the present embodiment”) will be described in detail.
The following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be appropriately modified and carried out within the scope of the gist thereof.

[Rubber composition]
The rubber composition of this embodiment is
With 100 parts by mass of rubber component,
30 to 150 parts by mass of silica with a nitrogen adsorption specific surface area of 180 m ^{2 / g or more,}
, Contain.
The rubber component contains 10% by mass or more of the conjugated diene polymer.
The conjugated diene polymer is
The Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less.
The Mooney relaxation rate measured at 100 ° C. is 0.35 or less.
The degree of branching (Bn) by the GPC-light scattering method with a viscosity detector is 8 or more.
The rubber composition of the present embodiment has extremely excellent workability when made into a vulcanized product, has particularly excellent wear resistance and steering stability when made into a vulcanized product, and has low hysteresis loss. Excellent and has sufficient breaking strength for practical use.

(Rubber component)
The rubber composition of the present embodiment contains a rubber component, and the rubber component contains 10% by mass or more of a conjugated diene-based polymer described later.

<Conjugated diene polymer>
The conjugated diene polymer contained in the rubber composition of the present embodiment (hereinafter, may be referred to as the conjugated diene polymer of the present embodiment) has a Mooney viscosity of 40 or more and 170 as measured at 100 ° C. The Mooney relaxation rate measured at 100 ° C. is 0.35 or less, and the degree of branching by the GPC-light scattering method measurement method with a viscosity detector (hereinafter, also referred to as “Bn”) is 8 or more. ..
As described above, the rubber composition containing the conjugated diene-based polymer in which the Mooney viscosity, Mooney relaxation rate, and branching degree (Bn) measured at 100 ° C. are specified is suitable for processability when made into a vulcanized product. It is extremely excellent, has excellent wear resistance when made into a vulcanized product, and has excellent steering stability, and has sufficient fracture strength for practical use.
The conjugated diene-based polymer contained in the rubber composition of the present embodiment specifies the Mooney viscosity, Mooney relaxation rate, and branching degree (Bn) measured at 100 ° C., and further, vinyl bond in the conjugated diene bonding unit. By arbitrarily adjusting the amount and the amount of aromatic vinyl compound, it is extremely excellent in workability when it is made into a vulcanized product, and it is excellent in abrasion resistance and steering stability when it is made into a vulcanized product, which is sufficient for practical use. The glass transition temperature (hereinafter, also referred to as “Tg”) of the conjugated diene polymer can be arbitrarily adjusted while maintaining a sufficient breaking strength.
For example, by setting the amount of vinyl bond in the conjugated diene bond unit and the amount of aromatic vinyl compound low, the Tg of the conjugated diene polymer is reduced, and the abrasion resistance and breaking strength when made into a vulcanized product. Is improved, and there is a tendency to obtain a rubber composition having further excellent low hysteresis loss property.
Further, by setting a high amount of vinyl bond and amount of aromatic vinyl compound in the conjugated diene bond unit, the Tg of the conjugated diene polymer becomes high, and the processing performance when making a vulcanized product is improved. Further, there is a tendency to obtain a rubber composition having excellent wet skid resistance.

[Moony Viscosity]
The conjugated diene polymer of the present embodiment has a structure in which the degree of bifurcation (Bn) is specified to be 8 or more.
In general, a polymer having a branched structure tends to have a smaller molecular size when compared with a linear polymer having the same molecular weight. Therefore, the molecular weight of the polymer having a branched structure is determined by gel permeation chromatography (hereinafter, also referred to as “GPC”) measurement, which is a relative comparison method with a standard polystyrene sample, by sieving the polymer by the molecular size. Tends to be underestimated.
In addition, the absolute molecular weight measured by the GPC-light scattering method with a viscosity detector is directly observed by the light scattering method when compared with the polystyrene-equivalent molecular weight obtained by gel permeation chromatography (GPC) measurement. However, since the molecular weight (absolute molecular weight) is measured, it is not affected by the structure of the polymer or the interaction with the column packing material, and is not affected by the polymer structure such as the branched structure of the conjugated diene polymer. Although it tends to be able to measure accurately, it is easily affected by the detection method of the light scattering detector and is effective for relative comparison under specific measurement conditions, but it shows the true structure of the conjugated diene polymer. Difficult to identify.

On the other hand, the Mooney viscosity is an index showing the overall characteristics of the conjugated diene polymer including information on the molecular weight, molecular weight distribution, branching degree, and content of the softener of the conjugated diene polymer. Further, the method for measuring the Mooney viscosity is defined in ISO289, and the error of the measured value due to the machine difference is small, which is extremely effective in controlling the performance of the conjugated diene polymer.
Generally, viscosity can be regarded as an index that substitutes for molecular weight, but since it is difficult to accurately grasp the molecular weight of a polymer having a branched structure, the present inventors have described the conjugated diene system of the present embodiment. Mooney viscosity was set as one of the requirements for the polymer.
The conjugated diene polymer of the present embodiment has a Mooney viscosity (hereinafter, also referred to as “ML”) measured at 100 ° C. of 40 or more and 170 or less, but usually, the molecular weight is simply lowered in a region near the lower limit. Even if the ML is adjusted or the ML is adjusted by adding a softening agent (oil or the like), the Mooney relaxation rate (hereinafter, also referred to as “MSR”) measured at 100 ° C. is kept at 0.35 or less. That is difficult. On the other hand, by setting the degree of branching (Bn) of the conjugated diene polymer to 8 or more, it becomes easy to control the MSR to 0.35 or less.
The MSR can be controlled by adjusting the type of branching agent, its addition amount, the type of coupling agent, and the addition amount thereof.
That is, in order to obtain a rubber composition exhibiting the desired performance, control of the molecular weight of the conjugated diene polymer and control of the Mooney viscosity were not sufficient. Therefore, in the present embodiment, the rubber composition is used. From the viewpoint of increasing the elastic modulus, the degree of branching of the conjugated diene polymer is increased to 8 or more in addition to the Mooney viscosity (adjust the type and amount of branching agent, and adjust the type and amount of coupling agent). By combining the above requirements, the elastic modulus (rigidity) of the vulcanized product was increased without impairing the processability of the rubber composition, and the steering stability was improved.

The conjugated diene-based polymer has the productivity of the conjugated diene-based polymer, the processability when a rubber composition containing a filler such as silica, etc. is prepared, and the resistance when the rubber composition is a vulcanized product. From the viewpoint of abrasion resistance, steering stability, and breaking strength, the Moony relaxation rate and the degree of branching (Bn) described later are within a specific range, and the Moony viscosity measured at 100 ° C. is 40 or more and 170 or less. Yes, preferably 50 or more and 150 or less, and more preferably 55 or more and 130 or less.
When the Mooney viscosity measured at 100 ° C. is 40 or more, the abrasion resistance and fracture strength of the vulcanized product tend to improve, and when the Mooney viscosity measured at 100 ° C. is 170 or less. It suppresses the occurrence of trouble in the production of the conjugated diene-based polymer, and improves the processability when the rubber composition is blended with a filler such as silica.

As a method for adjusting the Mooney viscosity of the conjugated diene polymer within the above range, 1 part by mass or more and 60 parts by mass or less of a softening agent for rubber, which will be described later, is added to 100 parts by mass of the conjugated diene polymer. The method can be mentioned.
Specifically, when a conjugated diene-based polymer is produced by continuous polymerization, an operation of stretching with oil or the like is generally performed, but such stretching lowers the Mooney viscosity and increases the Mooney relaxation rate.
From this point of view, the present inventors can appropriately control the processability of the conjugated diene polymer by specifying the stretched and finished state rather than the state of the conjugated diene polymer alone. Focusing on this, when finishing by adding a softening agent for rubber, it was decided to specify the Mooney viscosity of the conjugated diene polymer in the state of containing the softening agent for rubber.

For the measurement of Mooney viscosity, a sample obtained by forming a plate of a conjugated diene polymer with a pressure press was set in an apparatus, the sample was first preheated at 100 ° C. for 1 minute, and then the rotor was rotated at 2 rpm. The torque after 4 minutes is measured, and the measured value is defined as Mooney viscosity (ML _{(1 + 4)} ). More specifically, it can be measured by the method described in Examples described later.

[Moony relaxation rate]
The conjugated diene-based polymer preferably has a Mooney relaxation rate measured at 100 ° C. (hereinafter, also simply referred to as “Moony relaxation rate” or “MSR”) of 0.35 or less.
Like the Mooney viscosity, the Mooney relaxation rate is affected by the molecular weight, molecular weight distribution, branching degree, and content of the softener of the conjugated diene polymer, and is an index showing the overall characteristics of the conjugated diene polymer.

The conjugated diene polymer of the present embodiment has a Mooney viscosity measured at 100 ° C. within a specific range of 40 to 170, a branching degree (Bn) described later of 8 or more, and Mooney measured at 100 ° C. The relaxation rate is 0.35 or less.
Generally, the Moony viscosity can be lowered by lowering the molecular weight, lowering the degree of branching, or increasing the amount of the rubber softener added, but such a method increases the Mooney relaxation rate. Therefore, it is difficult to control the Mooney relaxation rate, which is a requirement of the conjugated diene-based polymer contained in the rubber composition of the present embodiment, only by reducing the Mooney viscosity by such a method.

The Mooney relaxation rate is an index of molecular entanglement of a conjugated diene polymer, and the lower it is, the more molecular entanglement is, and it is an index of a branched structure and a molecular weight.
For example, when comparing conjugated diene-based polymers having the same Mooney viscosity, the more branches of the conjugated diene-based polymer, the smaller the Mooney relaxation rate (MSR). Therefore, the MSR in this case is used as an index of the degree of branching. Can be used.

The conjugated diene-based polymer of the present embodiment has a Moony relaxation rate of 0.35 or less, and in order to reduce the Mooney relaxation rate to 0.35 or less in the conjugated diene-based polymer, the weight average molecular weight is increased. It is effective to control the molecular structure so as to widen the molecular weight distribution and increase the degree of branching in order to increase the number of high molecular weight components.
For example, in a conjugated diene polymer, if the Mooney viscosity is 40 or more and the degree of bifurcation (Bn) described later is 8 or more, the Mooney relaxation rate tends to be 0.35 or less.
The Mooney relaxation rate is the amount of the polymerization initiator added, the functional number of the branching agent used, the amount of the branching agent added, the coupling agent or the nitrogen atom-containing modifier in the process of producing the conjugated diene polymer. It can be controlled by adjusting the number of functional groups, the amount of the coupling agent or the amount of the modifier containing a nitrogen atom added.
For example, the amount of the polymerization initiator added is reduced to increase the molecular weight of the conjugated diene polymer before coupling, and then a branching agent having a large number of functional groups is added to obtain a coupling agent having a large number of functional groups or a nitrogen atom. By coupling with the contained modifier, a conjugated diene polymer having a Mooney viscosity of 40 or more, a branching degree (Bn) of 8 or more, and a Mooney relaxation rate of 0.35 or less tends to be obtained.

In the conjugated diene polymer of the present embodiment, the Mooney relaxation rate measured at 100 ° C. is 0.35 or less, preferably 0.32 or less, more preferably 0.30 or less, and 0. It is more preferably .28 or less. Further, the lower limit of the Moony relaxation rate is not particularly limited and may be not less than the detection limit value, but is preferably 0.05 or more.
When the Moony relaxation rate is 0.35 or less, when a rubber composition containing a filler such as silica is prepared, the incorporation of the filler such as silica into the conjugated diene polymer is improved, and the rubber composition is prepared. Tends to show good workability. Further, when the rubber composition is a vulcanized product, the elastic modulus of the vulcanized product tends to be particularly high, and a rubber composition having excellent steering stability, abrasion resistance, and fracture strength tends to be obtained. be.

The Mooney relaxation rate (MSR) can be measured using a Mooney viscometer as follows.
The measurement temperature of the Mooney relaxation rate is 100 ° C., the sample is preheated for 1 minute under the temperature condition of 100 ° C., the rotor is rotated at 2 rpm, and the Mooney viscosity (ML _{(1 + 4)) is obtained from the torque 4 minutes later.} ) Is measured, the rotation of the rotor is stopped immediately, the torque every 0.1 seconds for 1.6 seconds to 5 seconds after the stop is recorded in Mooney units, and the torque and time (seconds) are plotted in both logarithmic values. The slope of the straight line is obtained, and the absolute value is taken as the Mooney relaxation rate (MSR).
More specifically, it can be measured by the method described in Examples described later.

In order to reduce the Mooney relaxation rate to 0.35 or less, as described above, the weight average molecular weight is increased, the molecular weight distribution is widened to increase the high molecular weight component, and the molecular structure is controlled so as to increase the degree of branching. Is effective.
For example, in a conjugated diene polymer, if the Mooney viscosity is 40 or more and the degree of bifurcation (Bn) is 8 or more, the Mooney relaxation rate tends to be 0.35 or less.
Further, in order to make the Moony relaxation rate 0.30 or less, for example, in the conjugated diene polymer, if the Moony viscosity is 60 or more and the degree of bifurcation (Bn) is 8 or more, the Moony relaxation rate is 0.30. It tends to be as follows.
Further, the degree of branching (Bn) is, for example, the functional number of the branching agent, the amount of the branching agent added, the number of functional groups of the coupling agent or the nitrogen atom-containing modifier, the coupling agent or the nitrogen atom-containing modification. It can be controlled by adjusting the amount of the agent added.

[Bifurcation degree (Bn)]
From the viewpoint of processability, abrasion resistance, and fracture strength, the conjugated diene polymer of the present embodiment has a degree of branching (Bn) by the GPC-light scattering method with a viscosity detector (hereinafter, simply referred to as the degree of branching (Bn)). Also referred to as) is 8 or more.
When the degree of branching (Bn) is 8 or more, it means that the conjugated diene polymer has 8 or more side chain polymer chains with respect to the substantially longest polymer main chain.
The degree of branching (Bn) of the conjugated diene polymer is g'= 6Bn / [(Bn + 1) (Bn + 2) using a shrinkage factor (g') measured by the GPC-light scattering method with a viscosity detector. ] Is defined.
In general, a polymer having a branch tends to have a smaller molecular size when compared with a linear polymer having the same absolute molecular weight.
The shrinkage factor (g') is an index of the ratio of the size occupied by the molecule to the linear polymer having the same absolute molecular weight. That is, as the degree of branching of the polymer increases, the contraction factor (g') tends to decrease.
In the present embodiment, the intrinsic viscosity is used as an index of the size of the molecule for this contractile factor, and the linear polymer follows the relational expression of ^{the intrinsic viscosity [η] = -3.883M 0.771.} In the above formula, M is an absolute molecular weight.
However, the contractile factor expresses the rate of decrease in the size of the molecule, and does not accurately represent the branched structure of the polymer.
Therefore, the degree of branching (Bn) of the conjugated diene polymer is calculated by using the value of the shrinkage factor (g') at each absolute molecular weight of the conjugated diene polymer. The calculated "branch degree (Bn)" accurately represents the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.
The calculated degree of bifurcation (Bn) serves as an index for expressing the bifurcation structure of the conjugated diene-based polymer. For example, in the case of a general 4-branched star-shaped polymer (4 polymer chains connected to the center), two polymer chain arms are bonded to the longest highly branched main chain structure. , The degree of branching (Bn) is evaluated as 2.
In the case of a general 8-branched star-shaped polymer, 6 arms of the polymer chain are bonded to the longest highly branched main chain structure, and the degree of branching (Bn) is evaluated as 6.
The conjugated diene-based polymer contained in the rubber composition of the present embodiment has a branching degree (Bn) of 8 or more, but in such a case, the branched polymer structure is branched in the same manner as the star-shaped polymer structure. It means that it is a conjugated diene-based polymer having.
Here, the "branch" is formed by directly or indirectly binding another polymer to one polymer. Further, the “degree of branching (Bn)” is the number of polymers directly or indirectly bonded to each other with respect to the longest main chain structure.
When the degree of branching (Bn) is 8 or more, the conjugated diene polymer is extremely excellent in processability when it is made into a vulcanized product, and is excellent in wear resistance and fracture strength when it is made into a vulcanized product.

Generally, when the absolute molecular weight increases, the workability tends to deteriorate, and when the absolute molecular weight is increased in a linear polymer structure, the viscosity of the vulcanized product increases significantly, and the workability is significantly improved. Getting worse.
Therefore, even if a large number of functional groups are introduced into the conjugated diene polymer to improve the affinity and / or reactivity with the silica blended as a filler, the silica is sufficiently conjugated in the kneading step. It cannot be dispersed in the polymer. As a result, the function of the introduced functional group is not exhibited, and the effect of improving the low hysteresis loss property and the wet skid resistance due to the introduction of the functional group, which should be originally expected, tends not to be exhibited.
On the other hand, in the rubber composition of the present embodiment, by specifying the conjugated diene-based polymer as having a branching degree (Bn) of 8 or more, the viscosity of the vulcanized product increases as the absolute molecular weight increases. Is significantly suppressed, for example, it becomes sufficiently mixed with silica or the like in the kneading step, and silica can be dispersed around the conjugated diene polymer. As a result, for example, in a conjugated diene-based polymer, by setting a large molecular weight, it is possible to improve wear resistance and fracture strength, and silica is dispersed around the polymer by sufficient kneading to form functional groups. A rubber composition capable of acting and / or reacting, and having practically sufficient low hysteresis loss property and wet skid resistance can be obtained.
The absolute molecular weight of the conjugated diene polymer can be measured by the method described in Examples described later.

The conjugated diene polymer contained in the rubber composition of the present embodiment has a degree of branching (Bn) of 8 or more, preferably 10 or more, more preferably 12 or more, and further preferably 15 or more. ..
Conjugated diene-based polymers having a degree of branching (Bn) in this range tend to be excellent in processability when made into a vulcanized product.
The upper limit of the degree of branching (Bn) of the conjugated diene polymer is not particularly limited and may be at least the detection limit, but is preferably 84 or less, more preferably 80 or less, and further preferably. Is 64 or less, and even more preferably 57 or less.
When the degree of branching (Bn) of the conjugated diene polymer is 84 or less, it tends to have excellent wear resistance when it is made into a vulcanized product.

The degree of branching of the conjugated diene polymer can be controlled to 8 or more by the combination of the amount of the branching agent added and the amount of the terminal coupling agent added.
Specifically, the degree of branching is controlled by the number of functional groups of the branching agent, the amount of the branching agent added, the timing of addition of the branching agent, the number of functional groups of the coupling agent or the denaturant containing a nitrogen atom, and the coupling. It can be controlled by adjusting the amount of the agent or the denaturing agent containing a nitrogen atom. More specifically, it will be described in the method for producing a conjugated diene polymer described later.

[Coupling conjugated diene polymer]
In the step of producing the conjugated diene-based polymer of the present embodiment, a trifunctional or higher-functional reactive compound (hereinafter, "coupling agent") with respect to the active terminal of the conjugated diene-based polymer obtained through the polymerization and branching steps. It is preferable to carry out the coupling reaction using (also referred to as).
In the coupling reaction step, a coupling reaction is carried out with one end of the active end of the conjugated diene polymer with a coupling agent or a coupling agent having a nitrogen atom-containing group to obtain a conjugated diene polymer. More specifically, it will be described in the method for producing a conjugated diene polymer described later.

[Coupling agent]
In the present embodiment, the coupling agent used in the coupling reaction step may have any structure as long as it is a trifunctional or higher functional reactive compound, but is preferably a trifunctional or higher functional reactive compound having a silicon atom. be. More specifically, it will be described in the method for producing a conjugated diene polymer described later.

The conjugated diene polymer of the present embodiment preferably contains a nitrogen atom. The conjugated diene-based polymer containing a nitrogen atom can be obtained, for example, by carrying out a coupling reaction using the modifier having a nitrogen atom-containing group described below.

[Denaturant with nitrogen atom-containing group]
The conjugated diene polymer of the present embodiment is a reactive compound having trifunctionality or higher and having a nitrogen atom-containing group with respect to the active terminal of the conjugated diene polymer obtained through the polymerization and branching steps. A conjugated diene polymer obtained by performing a coupling reaction using a sex compound (hereinafter, also referred to as “modifier having a nitrogen atom-containing group”) is more preferable.
In the coupling reaction step, one end of the active end of the conjugated diene polymer is subjected to a coupling reaction with a modifier having a nitrogen atom-containing group to obtain a conjugated diene polymer.
The conjugated diene-based polymer coupled with a modifier having a nitrogen atom-containing group has good silica dispersibility and good processability when a rubber composition containing a filler such as silica is prepared. In addition, when it is made into a vulcanized product, it has good wear resistance and fracture strength, and the balance between low hysteresis loss property and wet skid resistance tends to be dramatically improved. More specifically, it will be described in the method for producing a conjugated diene polymer described later.

The modifier having a nitrogen atom-containing group is not limited to the following, but is, for example, an isocyanato compound, an isothiocyanate compound, an isocyanuric acid derivative, a nitrogen group-containing carbonyl compound, a nitrogen group-containing vinyl compound, and a nitrogen group-containing modifier. Examples include epoxy compounds.
The nitrogen atom-containing functional group of the modifier having a nitrogen atom-containing group is preferably an amine compound having no active hydrogen, for example, a tertiary amine compound, a protected amine in which the above-mentioned active hydrogen is substituted with a protective group. Examples thereof include a compound, an imine compound represented by the general formula −N = C, and an alkoxysilane compound bonded to the nitrogen atom-containing group. More specifically, it will be described in the method for producing a conjugated diene polymer described later.

[Denaturation rate of conjugated diene polymer]
The conjugated diene polymer of the present embodiment has a modification rate of 60% by mass or more as measured by the column adsorption GPC method.
In the present specification, the "modification rate" represents the mass ratio of the conjugated diene polymer having a nitrogen atom-containing group to the total amount of the conjugated diene polymer.
For example, when a nitrogen atom-containing modifier is reacted at the terminal end, the mass ratio of the conjugated diene polymer having a nitrogen atom-containing functional group by the nitrogen atom-containing modifier to the total amount of the conjugated diene polymer is modified. Expressed as a rate.
On the other hand, even when the polymer is branched by a branching agent containing a nitrogen atom, the produced conjugated diene-based polymer has a nitrogen atom-containing functional group, so that the branched polymer also has a modification rate. It will be counted at the time of calculation.
That is, in the present specification, the total mass ratio of the polymer coupled by the denaturing agent having a nitrogen atom-containing functional group and / or the polymer branched by the branching agent having a nitrogen atom-containing functional group is , "Degeneration rate".

The conjugated diene polymer of the present embodiment has at least one end modified with a nitrogen atom-containing group, so that the rubber composition can be processed into a rubber composition containing a filler or the like, and the rubber composition is vulcanized. The balance between low hysteresis loss and wet skid resistance tends to be dramatically improved while maintaining the wear resistance and fracture strength of the product.

The conjugated diene polymer of the present embodiment is a column with respect to the total amount of the conjugated diene polymer from the viewpoint of processability, abrasion resistance, fracture strength, and balance between low hysteresis loss property and wet skid resistance. The modification rate measured by the adsorption GPC method (hereinafter, also simply referred to as “modification rate”) is preferably 60% by mass or more.

The modification rate is preferably 65% by mass or more, more preferably 70% by mass or more, still more preferably 75% by mass or more, and even more preferably 80% by mass or more. The upper limit of the modification rate is not particularly limited, but is, for example, 98% by mass.
The modification rate can be measured by chromatography capable of separating the functional group-containing modified component and the non-modified component.
As a method using this chromatography, a column for gel permeation chromatography using a polar substance such as silica that adsorbs a specific functional group as a filler is used, and the internal standard of the non-adsorbed component is quantified by comparison. A method (column adsorption GPC method) can be mentioned.
More specifically, the modification rate is the adsorption of a sample solution containing a sample and a low molecular weight internal standard polystyrene to a silica column from the difference between a chromatogram measured on a polystyrene gel column and a chromatogram measured on a silica column. Obtained by measuring the amount.
More specifically, the denaturation rate can be measured by the method described in Examples.

The modification rate of the conjugated diene polymer can be controlled by adjusting the addition amount of the modifier and the reaction method, whereby it can be controlled to 60% by mass or more.
For example, a method of polymerizing using an organic lithium compound having at least one nitrogen atom in the molecule described later as a polymerization initiator, a method of copolymerizing a monomer having at least one nitrogen atom in the molecule, which will be described later. The above modification rate can be obtained by combining methods using a modifier having a structural formula and controlling the polymerization conditions.

[Branched structure of conjugated diene polymer]
The conjugated diene polymer of the present embodiment is a conjugated diene polymer having a star-shaped polymer structure having three or more branches from the viewpoint of a balance between processability and abrasion resistance, and has at least one star-shaped structure. The branched chain of the above has a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, and a portion derived from a vinyl-based monomer containing the alkoxysilyl group or a halosilyl group further comprises a main chain. It is preferably a conjugated diene polymer having a branched structure.

The "star-shaped polymer structure" as used herein refers to a structure in which a plurality of polymer chains (arms) are bonded from one central branch point.
Further, one central branching point referred to here has a substituent containing an atom derived from a coupling agent or a nitrogen atom derived from a denaturing agent.
The "main chain branched structure" referred to in the present specification means that a branched point is formed at a portion where the polymer chain is derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, and the polymer chain is further formed from the branched point. A structure in which the (arm) is extended.

From the viewpoint of improving the degree of branching (Bn) of the conjugated diene-based polymer, the main chain branching point composed of a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group in the conjugated diene-based polymer is , 2 or more branch points, preferably 3 or more branch points, more preferably 4 or more branch points, and the branched structure derived from the star-shaped polymer structure formed by the coupling agent in the reaction step is It is preferably 3 branches or more, more preferably 4 branches or more, further preferably 6 branches or more, and even more preferably 8 branches or more.
The degree of branching (Bn) increases in both the case of modification with a coupling agent having a star-shaped structure and the case of introducing a branching agent into the polymer, but the entire polymer chain is branched by the coupling agent. The more it is made, the greater the contribution to the degree of branching (Bn).
In polymer design, the degree of branching (Bn) can be controlled by selecting the coupling agent, selecting the type of branching agent, and setting the amount, but the degree of branching (Bn) is also taken into consideration in consideration of the contribution rate. ) Is easy to control.

[Main chain branch structure]
The main chain branch structure has two or more branch points at a branch point derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, preferably three or more branch points, and preferably four or more branch points. Is more preferable.
Further, the branch point forming the main chain branch structure preferably has at least two or more polymer chains, more preferably three or more polymer chains that are not the main chain, and further preferably. Has four or more polymer chains that are not the main chain.
In particular, in the main chain branched structure composed of a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, when ^{signal detection is performed by 29} Si-NMR, the range is in the range of -45 ppm to -65 ppm, which is more limited. A peak derived from the main chain branched structure is detected in the range of -50 ppm to -60 ppm.

[Star-shaped polymer structure]
The conjugated diene polymer of the present embodiment preferably has a star-shaped polymer structure, preferably has three or more branches derived from the star-shaped polymer structure, and preferably has four or more branches. More preferably, it is more preferably 6 branches or more, and even more preferably 8 branches or more.
A conjugated diene-based polymer having a star-shaped polymer structure having three or more branches, and having a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group in at least one branched chain of the star-shaped structure. The method for producing a conjugated diene polymer having a further main chain branched structure in the portion derived from the vinyl monomer containing the alkoxysilyl group or the halosilyl group is first described in the above-mentioned "star-shaped polymer structure". Can be formed by adjusting the number of functional groups of the coupling agent and the amount of the coupling agent added, and the "main chain branching structure" is the number of functional groups of the branching agent, the amount of the branching agent added, and the addition of the branching agent. It can be controlled by adjusting the timing of.
As a specific production method, polymerization is carried out using an organolithium compound as a polymerization initiator, a branching agent that gives a specific branching point during or after the polymerization is added, and a specific branching ratio is continued after the polymerization is continued. There is a method of denaturing using a denaturing agent that gives.
The means for controlling such polymerization conditions will be described in the production method in Examples described later.

[Details of main chain branch structure]
In the conjugated diene polymer of the present embodiment, the portion derived from the vinyl monomer containing the alkoxysilyl group or the halosilyl group described above is a single amount based on the compound represented by the following formula (1) or (2). It is preferable that the body unit has a branch point of the polymer chain due to the monomer unit based on the compound represented by the following formula (1) or (2). The conjugated diene polymer of the present embodiment is more preferably a conjugated diene polymer obtained by using a coupling agent, and at least one end of the conjugated diene polymer is modified with a nitrogen atom-containing group. It is more preferably a modified conjugated diene-based polymer.

(In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in a part thereof.
R ^{2 to} R ³ each independently represent 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 a part thereof.
When there are a plurality of them, R ^{1 to} R ³ are independent of each other.
X ¹ represents an independent halogen atom.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3. )
(In the formula (2), R ^{2 to} R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, even if a part thereof has a branched structure. good.
When there are a plurality of them, R ^{2 to} R ⁵ are independent of each other.
X ^{2 to} X ³ represent independent halogen atoms.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.
(M + n + l) indicates 3.
a indicates an integer of 0 to 2, b indicates an integer of 0 to 3, and c indicates an integer of 0 to 3. (A + b + c) indicates 3. )

In the conjugated diene polymer of the present embodiment, in the above-mentioned formula (1), R ¹ is a hydrogen atom and m = 0, and the monomer unit based on the compound represented by the above formula (1) is used. It is preferably a conjugated diene-based polymer having. As a result, the number of branches is increased, and the effect of improving wear resistance and workability can be obtained.

Further, the conjugated diene polymer of the present embodiment has a monomer unit based on the compound represented by the formula (2), in which m = 0 and b = 0 in the formula (2). , It is preferable that it is a conjugated diene-based polymer. As a result, the effect of improving wear resistance and workability can be obtained.

Further, in the above formula (2), the conjugated diene polymer of the present embodiment has m = 0, l = 0, n = 3, a = 0, b = 0, and c = 3. It is preferably a modified conjugated diene-based polymer having a monomer unit based on the compound represented by the formula (2). As a result, the effects of improving wear resistance and workability can be obtained.

Further, in the conjugated diene polymer of the present embodiment, in the above formula (1), R ¹ is a hydrogen atom, m = 0, l = 0, and n = 3. ), A conjugated diene-based polymer having a monomer unit based on the compound represented by) is more preferable. As a result, the modification rate and the degree of bifurcation are improved, and the effects of improving fuel efficiency, wear resistance and workability can be obtained.

<Branching agent>
In the conjugated diene polymer of the present embodiment, when constructing the main chain branching structure, it is preferable to use a branching agent represented by the following formula (1) or formula (2) as the branching agent.
The portion derived from the vinyl-based monomer containing the alkoxysilyl group or the halosilyl group is a monomer unit based on the compound represented by the following formula (1) or (2), and is the conjugated diene system of the present embodiment. The polymer preferably has a structure having a branch point of a polymer chain due to a monomer unit based on a compound represented by the following formula (1) or (2).

(In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in a part thereof.
R ^{2 to} R ³ each independently represent 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 a part thereof.
When there are a plurality of them, R ^{1 to} R ³ are independent of each other.
X ¹ represents an independent halogen atom.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.
(M + n + l) indicates 3. )
(In the formula (2), R ^{2 to} R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, even if a part thereof has a branched structure. good.
When there are a plurality of them, R ^{2 to} R ⁵ are independent of each other.
X ^{2 to} X ³ represent independent halogen atoms.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3.
(M + n + l) indicates 3.
a indicates an integer of 0 to 2, b indicates an integer of 0 to 3, and c indicates an integer of 0 to 3. (A + b + c) indicates 3. )

In the present embodiment, the branching agent used when constructing the main chain branching structure of the conjugated diene polymer is preferably of the formula (1) from the viewpoint of continuity of polymerization and improvement of branching degree. It is preferable that R ¹ is a hydrogen atom and m = 0.

Further, in the present embodiment, the branching agent used when constructing the main chain branching structure of the conjugated diene polymer is m = 0 in the formula (2) from the viewpoint of improving the degree of branching. And it is preferably a compound of b = 0.

Further, in the present embodiment, the branching agent used when constructing the main chain branching structure of the conjugated diene polymer is represented by the formula from the viewpoint of continuity of polymerization and improvement of modification rate and degree of branching. ^{It is more preferable that R 1 of} (1) is a hydrogen atom, m = 0, l = 0, and n = 3.

Further, in the present embodiment, the branching agent used when constructing the main chain branching structure of the conjugated diene polymer is m in the above formula (2) from the viewpoint of improving the modification rate and the degree of branching. Compounds with = 0, l = 0, n = 3 and a = 0, b = 0, c = 3 are preferred.

The branching agent represented by the formula (1) is not limited to the following, but for example, trimethoxy (4-vinylphenyl)silane, triethoxy (4-vinylphenyl)silane, and tripropoxy (4-vinylphenyl). ) Silane, tributoxy (4-vinylphenyl) silane, triisopropoxy (4-vinylphenyl) silane, trimethoxy (3-vinylphenyl) silane, triethoxy (3-vinylphenyl) silane, tripropoxy (3-vinylphenyl) silane , Tributoxy (3-vinylphenyl) silane, triisopropoxy (3-vinylphenyl) silane, trimethoxy (2-vinylphenyl) silane, triethoxy (2-vinylphenyl) silane, tripropoxy (2-vinylphenyl) silane, tributoxy (2-Vinylphenyl) silane, triisopropoxy (2-vinylphenyl) silane, dimethoxymethyl (4-vinylphenyl) silane, diethoxymethyl (4-vinylphenyl) silane, dipropoxymethyl (4-vinylphenyl) silane , 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) silane, dimethylethoxy (4-vinyl) Phenyl) 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, dimethylethoxy (2) -Vinylphenyl Le) Silane, dimethylpropoxy (2-vinylphenyl) silane, dimethylbutoxy (2-vinylphenyl) silane, dimethylisopropoxy (2-vinylphenyl) silane, trimethoxy (4-isopropenylphenyl) silane, triethoxy (4-isopro) Penylphenyl) silane, tripropoxy (4-isopropenylphenyl) silane, tributoxy (4-isopropenylphenyl) silane, triisopropoxy (4-isopropenylphenyl) silane, trimethoxy (3-isopropenylphenyl) silane, triethoxy ( 3-Isopropenylphenyl) silane, tripropoxy (3-isopropenylphenyl) silane, tributoxy (3-isopropenylphenyl) silane, triisopropoxy (3-isopropenylphenyl) silane, trimethoxy (2-isopropenylphenyl) silane , Triethoxy (2-isopropenylphenyl) silane, tripropoxy (2-isopropenylphenyl) silane, tributoxy (2-isopropenylphenyl) silane, triisopropoxy (2-isopropenylphenyl) silane, dimethoxymethyl (4-isopro) Penylphenyl) silane, diethoxymethyl (4-isopropenylphenyl) silane, dipropoxymethyl (4-isopropenylphenyl) silane, dibutoxymethyl (4-isopropenylphenyl) silane, diisopropoxymethyl (4-isoprope) Nylphenyl) silane, dimethoxymethyl (3-isopropenylphenyl) silane, diethoxymethyl (3-isopropenylphenyl) silane, dipropoxymethyl (3-isopropenylphenyl) silane, dibutoxymethyl (3-isopropenylphenyl) silane , Diisopropoxymethyl (3-isopropenylphenyl) silane, dimethoxymethyl (2-isopropenylphenyl) silane, diethoxymethyl (2-isopropenylphenyl) silane, dipropoxymethyl (2-isopropenylphenyl) silane, di Butoxymethyl (2-isopropenylphenyl) silane, diisopropoxymethyl (2-isopropenylphenyl) silane, dimethylmethoxy (4-isopropenylphenyl) silane, dimethylethoxy (4-isopropenylphenyl) silane, dimethylpropoxy (4) -Isopropenylphenyl) silane, dimethylbutoxy (4-isopropenylphenyl) silane, dimethylisopro Poxy (4-isopropenylphenyl) silane, dimethylmethoxy (3-isopropenylphenyl) silane, dimethylethoxy (3-isopropenylphenyl) silane, dimethylpropoxy (3-isopropenylphenyl) silane, dimethylbutoxy (3-isoprope) Nylphenyl) silane, dimethylisopropoxy (3-isopropenylphenyl) silane, dimethylmethoxy (2-isopropenylphenyl) silane, dimethylethoxy (2-isopropenylphenyl) silane, dimethylpropoxy (2-isopropenylphenyl) silane, dimethyl Butoxy (2-isopropenylphenyl) silane, dimethylisopropoxy (2-isopropenylphenyl) silane, trichloro (4-vinylphenyl) silane, trichloro (3-vinylphenyl) silane, trichloro (2-vinylphenyl) silane, tribromo (4-Vinylphenyl) silane, tribromo (3-vinylphenyl) silane, tribromo (2-vinylphenyl) silane, dichloromethyl (4-vinylphenyl) silane, dichloromethyl (3-vinylphenyl) silane, dichloromethyl (2) -Vinylphenyl) silane, dibromomethyl (4-vinylphenyl) silane, dibromomethyl (3-vinylphenyl) silane, dibromomethyl (2-vinylphenyl) silane, dimethylchloro (4-vinylphenyl) silane, dimethylchloro (3) Examples thereof include −vinylphenyl) silane, dimethylchloro (2-vinylphenyl) silane, dimethylbromo (4-vinylphenyl) silane, dimethylbromo (3-vinylphenyl) silane, and dimethylbromo (2-vinylphenyl) silane.

Among these, trimethoxy (4-vinylphenyl) silane, triethoxy (4-vinylphenyl) silane, tripropoxy (4-vinylphenyl) silane, tributoxy (4-vinylphenyl) silane triisopropoxy (4-vinylphenyl) Silane, trimethoxy (3-vinylphenyl) silane, triethoxy (3-vinylphenyl) silane, tripropoxy (3-vinylphenyl) silane, tributoxy (3-vinylphenyl) silane, triisopropoxy (3-vinylphenyl) silane, Trichloro (4-vinylphenyl) silane is preferred, trimethoxy (4-vinylphenyl) silane, triethoxy (4-vinylphenyl) silane, tripropoxy (4-vinylphenyl) silane, tributoxy (4-vinylphenyl) silane triisopropoxy. (4-Vinylphenyl) silane is more preferred.

The branching agent represented by the formula (2) is not limited to the following, but is, for example, 1,1-bis (4-trimethoxysilylphenyl) ethylene and 1,1-bis (4-triethoxy). Methoxyphenyl) ethylene, 1,1-bis (4-tripropoxysilylphenyl) ethylene, 1,1-bis (4-tripentoxysilylphenyl) ethylene, 1,1-bis (4-triisopropoxysilylphenyl) ) Ethylene, 1,1-bis (3-trimethoxysilylphenyl) ethylene, 1,1-bis (3-triethoxysilylphenyl) ethylene, 1,1-bis (3-tripropoxysilylphenyl) ethylene, 1 , 1-bis (3-tripentoxysilylphenyl) ethylene, 1,1-bis (3-triisopropoxysilylphenyl) ethylene, 1,1-bis (2-trimethoxysilylphenyl) ethylene, 1,1- Bis (2-triethoxysilylphenyl) ethylene, 1,1-bis (3-tripropoxysilylphenyl) 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, 1,1-bis (4- (Dipropylethoxysilyl) phenyl) ethylene can be mentioned.

Among these, 1,1-bis (4-trimethoxysilylphenyl) ethylene, 1,1-bis (4-triethoxysilylphenyl) ethylene, 1,1-bis (4-tripropoxysilylphenyl) ethylene , 1,1-bis (4? Tripentoxysilylphenyl) ethylene, 1,1-bis (4-triisopropoxysilylphenyl) ethylene is preferable, 1,1-bis (4-trimethoxysilylphenyl) ethylene, Is more preferable.

<Method for producing conjugated diene polymer>
The method for producing a conjugated diene polymer of the present embodiment is a method for producing a conjugated diene polymer having the above-mentioned Mooney viscosity, Mooney relaxation rate and degree of branching (Bn) in a specific range, and is an organic lithium compound. To obtain a conjugated diene-based polymer having a main chain branched structure by adding a branching agent while polymerizing at least the conjugated diene compound using the above as a polymerization initiator, and the above-mentioned conjugated diene-based polymer. With a coupling step of coupling with a coupling agent.

In the method for producing a conjugated diene polymer, at least one of the various branching agents described above is obtained by polymerizing at least the conjugated diene compound using the organic lithium compound as a polymerization initiator in the presence of the organic lithium compound. A polymerization and branching step of obtaining a conjugated diene polymer having a main chain branched structure using the above, and a coupling step of coupling the conjugated diene polymer with a coupling agent or a modifier having a nitrogen atom-containing group. And, it is preferable to have.

The conjugated diene-based polymer is either a homopolymer of a single conjugated diene compound, a polymer of different types of conjugated diene compounds, that is, a copolymer, or a copolymer of a conjugated diene compound and an aromatic vinyl compound. May be good.

The conjugated diene compound is not particularly limited, but for example, 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 preferable from the viewpoint of easy industrial availability.
These may be used alone or in combination of two or more.

The aromatic vinyl compound is not particularly limited, and examples thereof include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferable from the viewpoint of easy industrial availability.
These may be used alone or in combination of two or more.

As the so-called microstructure (ratio of the amount of the aromatic vinyl compound and the amount of the vinyl bond) of the copolymer of the conjugated diene compound and the aromatic vinyl compound, the amount of the aromatic vinyl compound is preferably 0 to 45% by mass, more preferably. It is 0 to 40% by mass, and the vinyl bond amount is preferably 23 to 70 mol%, more preferably 27 to 65 mol%. In the conjugated diene polymer, the Mooney viscosity, Mooney relaxation rate and degree of branching are determined by the amount of polymerization initiator added, the type (functional number) and amount of branching agent added, the type of coupling agent (functional number) and the amount added. , It is controlled by the amount (type) of the softener for rubber added, and the influence of the microstructure is small. Therefore, it can be appropriately designed within the range of a general microstructure. However, as described above, since the amount of the aromatic vinyl compound and the amount of the vinyl bond affect the Tg of the conjugated diene polymer, it is preferable to set them in the above ranges from the viewpoint of fuel saving performance and braking performance.

[Polymerization and branching process]
The polymerization and branching steps in the method for producing a conjugated diene polymer have a main chain branching structure, for example, by using an organic monolithium compound as a polymerization initiator, polymerizing at least the conjugated diene compound, and adding a branching agent. This is a step of obtaining a conjugated diene-based polymer.

In the polymerization step, it is preferable to carry out polymerization by a growth reaction by a living anionic polymerization reaction, whereby a conjugated diene-based polymer having an active terminal can be obtained. After that, the main chain branching can be appropriately controlled even in the branching step using a branching agent, and there is a tendency that a conjugated diene-based polymer having a high denaturation rate can be obtained.

[Polymerization initiator]
At least an organic monolithium compound can be used as the polymerization initiator.
The organic monolithium compound is not limited to the following, and examples thereof include low molecular weight compounds and organic monolithium compounds which are solubilized oligomers.
In addition, examples of the organic monolithium compound include a compound having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond in the bonding mode of the organic group and the lithium thereof.

The amount of the organic monolithium compound used as the polymerization initiator is preferably determined by the molecular weight of the target conjugated diene polymer.
The amount of a monomer such as a conjugated diene compound used relative to the amount of the polymerization initiator used is related to the degree of polymerization of the target conjugated diene polymer. That is, it tends to be related to the number average molecular weight and / or the weight average molecular weight.
Therefore, in order to increase the molecular weight of the conjugated diene polymer, it is preferable to adjust in the direction of reducing the amount of the polymerization initiator used, and in order to reduce the molecular weight, it is necessary to adjust in the direction of increasing the amount of the polymerization initiator used. good.

The organic monolithium compound is preferably an alkyllithium compound having a substituted amino group or a dialkylaminolithium from the viewpoint that it is used in one method of introducing a nitrogen atom into a conjugated diene-based polymer.
In this case, a conjugated diene-based polymer having a nitrogen atom composed of an amino group at the polymerization initiation terminal can be obtained.

The substituted amino group is an amino group having no active hydrogen or having a structure in which active hydrogen is protected.
The alkyllithium compounds having an amino group without active hydrogen are not limited to, for example, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4- (methylpropylamino) butyllithium, and 4 -Hexamethylene iminobutyllithium can be mentioned.
The alkyllithium compound having an amino group having a structure in which active hydrogen is protected is not limited to the following, and examples thereof include 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

The dialkylaminolithium is not limited to the following, and includes, for example, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithiumdi-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, and lithium dioctylamide. , Lithium-di-2-ethylhexylamide, lithiumdidecylamide, lithiumethylpropylamide, lithiumethylbutylamide, lithiumethylbenzylamide, lithiummethylphenethylamide, lithiumhexamethyleneimide, lithiumpyrrolidide, lithiumpiperidide, Lithium heptamethyleneimide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo [3.2.1] octane, and 1-lithio-1,2, Examples include 3,6-tetrahydropyridine.

These organic monolithium compounds having a substituted amino group were solubilized in normal hexane and cyclohexane by reacting a small amount of polymerizable monomers such as 1,3-butadiene, isoprene, and styrene. It can also be used as an organic monolithium compound of an oligomer.

The organic monolithium compound is preferably an alkyllithium compound from the viewpoint of easy industrial availability and easy control of the polymerization reaction. In this case, a conjugated diene-based polymer having an alkyl group at the polymerization initiation terminal can be obtained.
Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stillbenlithium.
As the alkyllithium compound, n-butyllithium and sec-butyllithium are preferable from the viewpoint of easy industrial availability and easy control of the polymerization reaction.

These organic monolithium compounds may be used alone or in combination of two or more. In addition, it may be used in combination with other organometallic compounds.
Examples of the other organometallic compound include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.
The alkaline earth metal compound is not limited to the following, and examples thereof include an organic magnesium compound, an organic calcium compound, and an organic strontium compound. Also included are compounds of alkaline earth metals alcoxide, sulfonate, carbonate, and amide.
Examples of the organic magnesium compound include dibutyl magnesium and ethyl butyl magnesium. Examples of other organometallic compounds include organoaluminum compounds.

In the polymerization step, the polymerization reaction mode is not limited to the following, and examples thereof include a batch type (also referred to as “batch type”) and a continuous type polymerization reaction mode.
In the continuous equation, one or two or more connected reactors can be used. As the continuous reactor, for example, a tank type or tube type reactor with a stirrer is used. In the continuous formula, preferably, the monomer, the inert solvent, and the polymerization initiator are continuously fed to the reactor to obtain a polymer solution containing the polymer in the reactor, and the polymer solution is continuously weighted. The coalesced solution is drained.
As the batch reactor, for example, a tank-type reactor equipped with a stirrer is used. In the batch formula, preferably, the monomer, inert solvent, and polymerization initiator are fed, and if necessary, the monomer is added continuously or intermittently during the polymerization, and the polymer is added in the reactor. A polymer solution containing the mixture is obtained, and the polymer solution is discharged after the completion of the polymerization.
In the method for producing a conjugated diene polymer of the present embodiment, in order to obtain a conjugated diene polymer having an active terminal at a high ratio, the polymer must be continuously discharged and subjected to the next reaction in a short time. A possible, continuous system is preferred.

In the polymerization step of the conjugated diene polymer, it is preferable to polymerize in an inert solvent.
Examples of the inert solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon-based solvents are not limited to the following, but are, for example, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic groups such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane. Hydrocarbons; examples include hydrocarbons composed of aromatic hydrocarbons such as benzene, toluene and xylene and mixtures thereof.
By treating impurities such as allenes and acetylenes with an organometallic compound before subjecting them to a polymerization reaction, a conjugated diene-based polymer having a high concentration of active terminals tends to be obtained, and modification with a high modification rate. It is preferable because a conjugated diene-based polymer tends to be obtained.

In the polymerization step, a polar compound may be added. As a result, the aromatic vinyl compound can be copolymerized with the conjugated diene compound at random, and the polar compound tends to be used as a vinylizing agent for controlling the microstructure of the conjugated diene portion. It also tends to be effective in promoting the polymerization reaction.

The polar compound is not limited to the following, but is not limited to, for example, tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, 2,2-bis (2-oxolanyl). ) Ethers such as propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; potassium-tert-amylate, potassium-tert-butyrate, sodium-tert-butyrate, Alkoxide alkoxide compounds such as sodium amylate; phosphine compounds such as triphenylphosphine can be used.
These polar compounds may be used alone or in combination of two or more.

The amount of the polar compound used is not particularly limited and can be selected depending on the intended purpose and the like, but it is preferably 0.01 mol or more and 100 mol or less with respect to 1 mol of the polymerization initiator.
Such a polar compound (vinyl agent) can be used in an appropriate amount as a regulator of the microstructure of the conjugated diene portion of the conjugated diene polymer, depending on the desired amount of vinyl bond.
Many polar compounds have a randomizing effect that is effective in copolymerizing a conjugated diene compound and an aromatic vinyl compound at the same time, and tend to be used as an agent for adjusting the distribution of the aromatic vinyl compound or adjusting the amount of styrene block. It is in.
As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140211, the total amount of styrene and a part of 1,3-butadiene are copolymerized. A method of initiating the polymerization reaction and intermittently adding the remaining 1,3-butadiene during the copolymerization reaction may be used.

The polymerization temperature in the polymerization step is preferably a temperature at which living anionic polymerization proceeds, more preferably 0 ° C. or higher, and even more preferably 120 ° C. or lower, from the viewpoint of productivity. Within such a range, the amount of reaction of the denaturant to the active terminal after the completion of polymerization tends to be sufficiently secured. Even more preferably, it is 50 ° C. or higher and 100 ° C. or lower.

In the method for producing a conjugated diene polymer of the present embodiment, the amount of the branching agent added in the branching step of forming the main chain branching structure is not particularly limited and can be selected according to the purpose and the like. It is preferably 0.03 mol or more and 0.5 mol or less, more preferably 0.05 mol or more and 0.4 mol or less, and 0.01 mol or more and 0.25 mol or more, with respect to 1 mol of the polymerization initiator. More preferably, it is less than or equal to the molar amount.
An appropriate amount of the branching agent can be used according to the desired number of branching points of the main chain branching structure of the conjugated diene portion of the conjugated diene-based polymer of interest.

In the branching step, the timing of adding the branching agent is not particularly limited and can be selected according to the purpose and the like, but from the viewpoint of improving the absolute molecular weight and the modification rate of the conjugated diene polymer. After the addition of the polymerization initiator, the timing at which the raw material conversion rate is 20% or more is preferable, 40% or more is more preferable, 50% or more is further preferable, and 65% or more is even more preferable. Even more preferably, it is 75% or more.
Further, after adding the branching agent, a desired raw material may be further added to continue the polymerization step after branching, or the above description may be repeated.
The monomer to be added is not particularly limited, but is preferably 5% or more of the total amount of the conjugated diene-based monomer used in the polymerization step, for example, the total amount of butadiene, from the viewpoint of improving the modification rate of the conjugated diene-based polymer. It is more preferably 10% or more, further preferably 15% or more, further preferably 20% or more, further preferably 25% or more, and particularly preferably 30% or less. preferable.

When the amount of the monomer to be added is within the above range, the molecular weight between the branching point by the branching agent and the branching point by the coupling agent becomes long, and it tends to be easy to obtain a highly linear molecular structure. By adopting a highly linear molecular structure, the entanglement of the molecular chains of the conjugated diene polymer increases when it is made into a vulcanized product, and a rubber composition having excellent wear resistance, steering stability and fracture strength can be obtained. It tends to be obtained.

The conjugated diene-based polymer of the present embodiment may be a polymer of a conjugated diene monomer and a branching agent, or a copolymer of a conjugated diene monomer, a branching agent and a monomer other than these. good.
For example, when the conjugated diene monomer is butadiene or isoprene and this is polymerized with a branching agent containing a vinyl aromatic moiety, the polymerized chain is so-called polybutadiene or polyisoprene, and the branched moiety contains a structure derived from vinyl aromatic moiety. It becomes a polymer. Having such a structure has the effect of improving wear resistance, such as improving the linearity of each polymer chain and improving the crosslink density after vulcanization. Therefore, the conjugated diene polymer of the present embodiment is suitable for applications such as tires, resin modifications, automobile interior and exterior parts, anti-vibration rubber, and footwear.
When the conjugated diene-based polymer is used for a tread of a tire, a copolymer of a conjugated diene monomer, an aromatic vinyl monomer, and a branching agent is suitable, and the amount of the bonded conjugated diene in the copolymer for this application is 40 mass. It is preferably% or more and 100% by mass or less, and more preferably 55% by mass or more and 80% by mass or less.
The amount of bound aromatic vinyl in the conjugated diene polymer of the present embodiment is not particularly limited, but is preferably 0% by mass or more and 60% by mass or less, and is 20% by mass or more and 45% by mass or less. Is more preferable. When the amount of the bonded conjugated diene and the amount of the bonded aromatic vinyl are in the above ranges, the balance between the low hysteresis loss property and the wet skid resistance, the abrasion resistance, and the breaking strength of the vulture are more excellent. There is a tendency.
Here, the amount of bound aromatic vinyl can be measured by the ultraviolet absorption of the phenyl group, and the amount of bound conjugated diene can also be determined from this. Specifically, the measurement is performed according to the method described in Examples described later.

In the conjugated diene-based polymer of the present embodiment, the amount of vinyl bond in the conjugated diene bonding unit is not particularly limited, but is preferably 10 mol% or more and 75 mol% or less, and 20 mol% or more and 65 mol% or less. Is more preferable.
When the vinyl bond amount is in the above range, the balance between the low hysteresis loss property and the wet skid resistance, the wear resistance, and the fracture strength in the vulcanized product tend to be more excellent.
Here, when the conjugated diene-based polymer is a copolymer of butadiene and styrene, it is contained in the butadiene bond unit by the Hampton method (RR Hampton, Analytical Chemistry, 21,923 (1949)). The vinyl bond amount (1,2-bond amount) can be determined. Specifically, the measurement is performed by the method described in Examples described later.

Regarding the microstructure of the conjugated diene polymer of the present embodiment, the amount of each bond in the conjugated diene polymer is in the above range, and the glass transition temperature of the conjugated diene polymer is −70 ° C. or higher to −15 ° C. or higher. When the temperature is in the range of ° C. or lower, a more excellent vulcanized product tends to be obtained due to the balance between low hysteresis loss property and wet skid resistance.
Regarding the glass transition temperature, according to ISO 22768: 2006, the DSC curve is recorded while raising the temperature in a predetermined temperature range, and the peak top (Inflection point) of the DSC differential curve is defined as the glass transition temperature.

When the conjugated diene-based polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferable that the number of blocks in which 30 or more aromatic vinyl units are linked is small or absent. .. More specifically, when the conjugated diene polymer is a butadiene-styrene copolymer, it is described in Kolthoff's method (IM KOLTHOFF, et al., J. Polym. Sci. 1,429 (1946)). In a known method of decomposing a copolymer by (method) and analyzing the amount of polystyrene insoluble in methanol, blocks in which 30 or more aromatic vinyl units are linked are preferably 5 with respect to the total amount of the copolymer. It is 9.0% by mass or less, more preferably 3.0% by mass or less.

When the conjugated diene-based polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferable that the aromatic vinyl unit is present alone in a large proportion from the viewpoint of improving fuel saving performance.
Specifically, when the conjugated diene polymer is a butadiene-styrene copolymer, the conjugated diene weight is produced by an ozone decomposition method known as Tanaka et al. (Polymer, 22, 1721 (1981)). When the coalescence was decomposed and the styrene chain distribution was analyzed by GPC, the amount of isolated styrene was 40% by mass or more and the number of chained styrene structures having 8 or more styrene chains was 5.0% by mass based on the total amount of bound styrene. % Or less is preferable.
In this case, the obtained vulcanized rubber has excellent performance with a particularly low hysteresis loss.

[Coupling process]
The method for producing a conjugated diene polymer of the present embodiment includes a coupling step of coupling the conjugated diene polymer obtained through the above-mentioned polymerization and branching steps with a coupling agent.
In the coupling step, for example, a trifunctional or higher functional compound (hereinafter, also referred to as “coupling agent”) is used for the active terminal of the conjugated diene polymer, or a nitrogen atom-containing group is used. It is preferable to carry out the coupling reaction using the modifier having.

In the coupling step, for example, one end of the active end of the conjugated diene polymer is subjected to a coupling reaction with a coupling agent or a modifier having a nitrogen atom-containing group to obtain a conjugated diene polymer.

[Coupling agent]
In the method for producing a conjugated diene polymer of the present embodiment, the coupling agent used in the coupling step may have any structure as long as it is a trifunctional or higher functional reactive compound, but preferably has a silicon atom. It is a trifunctional or higher functional reactive compound.
The trifunctional or higher functional reactive compound having a silicon atom is not limited to the following, and includes, for example, a halogenated silane compound, an epoxidized silane compound, a vinylized silane compound, an alkoxysilane compound, and a nitrogen-containing group. Examples thereof include an alkoxysilane compound.

The halogenated silane compound which is a coupling agent is not limited to the following, and includes, for example, methyltrichlorosilane, tetrachlorosilane, tris (trimethylsiloxy) chlorosilane, tris (dimethylamino) chlorosilane, hexachlorodisilane, and bis ( Trichlorosilyl) methane, 1,2-bis (trichlorosilyl) ethane, 1,2-bis (methyldichlorosilyl) ethane, 1,4-bis (trichlorosilyl) butane, 1,4 bis (methyldichlorosilyl) butane, etc. Can be mentioned.

The epoxidized silane compound as a coupling agent is not limited to the following, and is, for example, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyl. Examples thereof include methyldiethoxysilane and epoxy-modified silicone.
Examples of the vinylylated silane compound as a coupling agent include, but are not limited to, trimethoxyvinylsilane, triethoxyvinylsilane, 1,3-divinyltetramethyldisiloxane, and the like.

Alkoxysilane compounds that are coupling agents are not limited to the following, but are, for example, tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, 1,2-bis (triethoxysilyl) ethane, and methoxy substitution. Examples thereof include polyorganosiloxane.

[Denaturant with nitrogen atom-containing group]
The modifier having a nitrogen atom content is not limited to the following, but is, for example, an isocyanato compound, an isothiocyanate compound, an isocyanuric acid derivative, a carbonyl compound having a nitrogen atom-containing group, and a vinyl having a nitrogen atom-containing group. Examples thereof include compounds and epoxy compounds having a nitrogen atom-containing group.

In the modifier having a nitrogen atom-containing group, the nitrogen atom-containing functional group is preferably an amine compound having no active hydrogen, for example, a tertiary amine compound, protection in which the above-mentioned active hydrogen is substituted with a protective group. Examples thereof include an amine compound, an imine compound represented by the general formula −N = C, and an alkoxysilane compound bonded to the nitrogen atom-containing group.

The isocyanate compound which is a modifying agent having a nitrogen atom-containing group is not limited to the following, and for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate. , Polymeric type diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3,5-benzenetriisocyanate and the like.

The isocyanuric acid derivative, which is a modifying agent having a nitrogen atom-containing group, is not limited to the following, and is, for example, 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate, 1,3. 5-Tris (3-triethoxysilylpropyl) isocyanurate, 1,3,5-tri (oxylan-2-yl) -1,3,5-triazinan-2,4,6-trione, 1,3,5 -Tris (isocyanatomethyl) -1,3,5-triazinan-2,4,6-trione, 1,3,5-trivinyl-1,3,5-triazinan-2,4,6-trione and the like. Be done.

The carbonyl compound, which is a modifier having a nitrogen atom-containing group, is not limited to the following, and is, for example, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazole. Lidinone, 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, methyl-2-pyridyl ketone, methyl-4-pyridyl ketone, propyl-2-pyridyl ketone, di-4-pyridyl ketone, 2-benzoyl Pyridine, N, N, N', N'-tetramethylurea, N, N-dimethyl-N', N'-diphenylurea, N, N-diethylcarbamate methyl, N, N-diethylacetamide, N, N Examples thereof include -dimethyl-N', N'-dimethylaminoacetamide, N, N-dimethylpicolinic acid amide, N, N-dimethylisonicotinic acid amide and the like.

The vinyl compound which is a modifying agent having a nitrogen atom-containing group is not limited to the following, and is, for example, N, N-dimethylacrylamide, N, N-dimethylmethacrylicamide, N-methylmaleimide, N-methyl. Phthalimide, N, N-bistrimethylsilylacrylamide, morpholinoacrylamide, 3- (2-dimethylaminoethyl) styrene, (dimethylamino) dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis (N, N-dimethylaniline) ), 4,4'-Vinylidenebis (N, N-diethylaniline), 1,1-bis (4-morpholinophenyl) ethylene, 1-phenyl-1- (4-N, N-dimethylaminophenyl) ethylene, etc. Can be mentioned.

The epoxy compound which is a modifier having a nitrogen atom-containing group is not limited to the following, and examples thereof include an epoxy group-containing hydrocarbon compound bonded to an amino group, and an epoxy group further bonded to an ether group. May have. Examples of such an epoxy compound include, but are not limited to, an epoxy compound represented by the general formula (i).

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

The divalent or higher valent hydrocarbon group is a saturated or unsaturated linear, branched, or cyclic hydrocarbon group, and includes an alkylene group, an alkenylene group, a phenylene group, and the like. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. For example, methylene, ethylene, butylene, cyclohexylene, 1,3-bis (methylene) -cyclohexane, 1,3-bis (ethylene) -cyclohexane, o-, m-, p-phenylene, m-, p-xylene, Examples include bis (phenylene) -methane.

In the formula (i), R ¹ and R ⁴ are hydrocarbon groups having 1 to 10 carbon atoms, and R ¹ and R ⁴ may be the same or different from each other.
In the formula (i), R ² and R ⁵ are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R ² and R ⁵ may be the same or different from each other.
In the formula (i), R ³ is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (ii).
R ¹ , R ² , and R ³ may have an annular structure connected to each other.
When R ³ is a hydrocarbon group, it may have a cyclic structure bonded to R. In the case of the above-mentioned cyclic structure, N and R bonded to ^{R 3 may be directly bonded.}
In the above formula (i), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

In the formula (ii), R ^1, R ² are defined as for R ^1, R ² in formula (i), R ^1, R ² may be the being the same or different.

As the epoxy compound which is a modifier having a nitrogen atom-containing group, one having an epoxy group-containing hydrocarbon group, particularly an epoxy group-containing hydrocarbon group bonded to an amino group or an ether group is preferable, and more preferably, a glycidyl group-containing carbide is used. It has a hydrogen group.
The epoxy group-containing hydrocarbon group bonded to the amino group or the ether group is not particularly limited, and examples thereof include a glycidylamino group, a diglycidylamino group, and a glycididoxy group. A more preferable molecular structure is an epoxy group-containing compound having a glycidylamino group or a diglycidylamino group and a glycididoxy group, respectively, and examples thereof include compounds represented by the following general formula (iii).

In the formula (iii), R is defined in the same manner as R in the formula (i), and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (iv).
When R ⁶ is a hydrocarbon group, it may be bonded to R to have a cyclic structure, and in that case, ^{N and R bonded to R 6} may be directly bonded to each other. ..
In the formula (iii), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

The epoxy compound having a nitrogen atom-containing group is particularly preferably a compound having one or more diglycidylamino groups and one or more glycidoxy groups in the molecule.

The epoxy compound used as a modifier having a nitrogen atom-containing group is not limited to the following, and for example, N, N-diglycidyl-4-glycidoxyaniline, 1-N, N-diglycidylaminomethyl-4. -Glysidoxy-cyclohexane, 4- (4-glycidoxyphenyl)-(N, N-diglycidyl) aniline, 4- (4-glycidoxyphenoxy)-(N, N-diglycidyl) aniline, 4- (4- (4-) Glycydoxybenzyl)-(N, N-diglycidyl) aniline, 4- (N, N'-diglycidyl-2-piperazinyl) -glycidoxybenzene, 1,3-bis (N, N-diglycidylaminomethyl) Cyclohexane, N, N, N', N'-tetraglycidyl-m-xylene diamine, 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-glycidyl piperazinyl)-(N, N-) Diglycidyl) aniline, 2- [2- (N, N-diglycidylamino) ethyl] -1-glycidylpyrrolidin, N, N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N, N- Examples thereof include diglycidyl aniline, N, N-diglycidyl orthotoluidine, N, N-diglycidyl aminomethylcyclohexane and the like. Of these, particularly preferable ones include N, N-diglycidyl-4-glycidoxyaniline and 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane.

The alkoxysilane compound which is a modifier having a nitrogen atom-containing group is not limited to the following, and is, for example, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyl. Triethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3- (4-methyl-1-piperazino) propyltriethoxysilane, 1 -[3- (Triethoxysilyl) -propyl] -3-methylhexahydropyrimidine, 3- (4-trimethylsilyl-1-piperazino) propyltriethoxysilane, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyl Diethoxysilane, 3- (3-trimethylsilyl-1-hexahydropyrimidinyl) propyltrimethoxysilane, 3-dimethylamino-2- (dimethylaminomethyl) propyltrimethoxysilane, bis (3-dimethoxymethylsilylpropyl) -N -Methylamine, bis (3-trimethoxysilylpropyl) -N-methylamine, bis (3-triethoxysilylpropyl) methylamine, tris (trimethoxysilyl) amine, tris (3-trimethoxysilylpropyl) amine, N, N, N', N'-tetra (3-trimethoxysilylpropyl) ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1- (3-tri Methoxysilylpropyl) -1-aza-2-silacyclopentane, 2,2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, 2,2-dimethoxy-1- (4-Trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2,2-dimethoxy-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclopentane, 2,2-dimethoxy -1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2 -Silacyclopentane, 2,2-dimethoxy-8- (4-methylpiperazinyl) methyl-1,6-dioxa-2-silacyclooctane, 2,2-dimethoxy-8- (N, N-diethylamino) Methyl-1 , 6-Dioxa-2-silacyclooctane and the like.

Modification agents having a nitrogen atom-containing group, as a protected amine compound capable of forming a primary or secondary amine, and a compound having an unsaturated bond and a protected amine in the molecule are not limited to the following. No, but for example, 4,4'-vinylidenebis [N, N-bis (trimethylsilyl) aniline], 4,4'-vinylidenebis [N, N-bis (triethylsilyl) aniline], 4,4'-vinylidene Bis [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], 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, 1- [4-N, N-bis (trimethylsilyl) aminophenyl]- Examples thereof include 1- [4-N, N-dimethylaminophenyl] ethylene.

The modifier having a nitrogen atom-containing group, as a protected amine compound capable of forming a primary or secondary amine, and a compound having alkoxysilane and a protected amine in the molecule is not limited to the following. However, for example, N, N-bis (trimethylsilyl) aminopropyltrimethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N, N- Bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, N, N-bis (triethylsilyl) amino Propylmethyldiethoxysilane, 3- (4-trimethylsilyl-1-piperazino) propyltriethoxysilane, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyldiethoxysilane, 3- (3-trimethylsilyl-1-hexa) Hydropyrimidinyl) 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-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2,2-dimethoxy-1- (3-dimethoxy) Methylsilylpropyl) -1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2 -Shiracyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane and the like can be mentioned.

Particularly preferable alkoxysilane compounds which are modifiers having a nitrogen atom-containing group are not limited to the following, but for example, tris (3-trimethoxysilylpropyl) amine and tris (3-triethoxysilylpropyl) amine. , Tris (3-tripropoxysilylpropyl) amine, bis (3-trimethoxysilylpropyl)-[3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] amine, tetrakis (3-) Trimethoxysilylpropyl) -1,3-propanediamine, tris (3-trimethoxysilylpropyl)-[3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1, 3-Propanediamine, Tris (3-trimethoxysilylpropyl)-[3- (1-methoxy-2-methyl-1-sila-2-azacyclopentane) propyl] -1,3-Propanediamine, Bis (3) -Triethoxysilylpropyl)-[3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl]-[3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclo) Pentan) Propyl] -1,3-Propyldiamine, Tetrax (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-trimethoxysilylpropyl) -Diethylenetriamine, tris (3-trimethoxysilylpropyl) -methyl-1,3-propanediamine, tetrakis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] silane, bis (3) -Trimethoxysilylpropyl) -bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] silane, tris [3- (2,2-dimethoxy-1-aza-2-sila) Cyclopentane) 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-dimethoki) Si-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, and tris [3- (2,2-dimethoxy-1-aza-2-sila) Cyclopentane) propyl] phosphate can be mentioned.

<Preferable structure of conjugated diene polymer>
The conjugated diene polymer of the present embodiment preferably contains a structure derived from a compound having a nitrogen atom-containing group represented by any of the following general formulas (i) or (A) to (C). ..

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

The divalent or higher valent hydrocarbon group is a saturated or unsaturated linear, branched, or cyclic hydrocarbon group, and includes an alkylene group, an alkenylene group, a phenylene group, and the like. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. For example, methylene, ethylene, butylene, cyclohexylene, 1,3-bis (methylene) -cyclohexane, 1,3-bis (ethylene) -cyclohexane, o-, m-, p-phenylene, m-, p-xylene, Examples include bis (phenylene) -methane.

In the formula (i), R ¹ and R ⁴ are hydrocarbon groups having 1 to 10 carbon atoms, and R ¹ and R ⁴ may be the same or different from each other.
In the formula (i), R ² and R ⁵ are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R ² and R ⁵ may be the same or different from each other.
In the formula (i), R ³ is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (ii).
R ¹ , R ² , and R ³ may have an annular structure connected to each other.
When R ³ is a hydrocarbon group, it may have a cyclic structure bonded to R. In the case of the above-mentioned cyclic structure, N and R bonded to ^{R 3 may be directly bonded.}
In the above formula (i), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

In the formula (ii), R ^1, R ² are defined as for R ^1, R ² in formula (i), R ^1, R ² may be the being the same or different.

(In the formula (A), R ^{1 to} R ⁴ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ⁵ has 1 to 10 carbon atoms. It represents an alkylene group, and R ⁶ represents an alkylene group having 1 to 20 carbon atoms.
m represents an integer of 1 or 2, n represents an integer of 2 or 3, and (m + n) represents an integer of 4 or more. When there are a plurality of them, R ^{1 to} R ⁴ are independent of each other. )

(In the formula (B), R ^{1 to} R ⁶ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and R ^{7 to} R ⁹ independently represent each other. , Indicates an alkylene group having 1 to 20 carbon atoms.
m, n, and l each independently represent an integer of 1 to 3, and (m + n + l) represents an integer of 4 or more. When there are a plurality of them, R ^{1 to} R ⁶ are independent of each other. )

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

The modifier having a nitrogen atom-containing group represented by the formula (A) is not limited to the following, but 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-silacycloheptan, 2,2-dimethoxy-1- (3-dimethoxymethyl) Cyrilpropyl) -1-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 can be mentioned.
Among these, m is 2 and n is 3 from the viewpoint of reactivity and interaction between the functional group of the modifier having a nitrogen atom-containing group and an inorganic filler such as silica, and from the viewpoint of processability. Is preferable. Specifically, 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane, and 2,2-diethoxy-1- (3-triethoxysilylpropyl)- 1-aza-2-silacyclopentane is preferred.

The reaction temperature, reaction time, etc. when reacting the modifier having a nitrogen atom-containing group represented by the formula (A) with the polymerization active terminal are not particularly limited, but are 0 ° C. or higher and 120 ° C. or lower. It is preferable to react for 30 seconds or more.

The total number of moles of the alkoxy groups bonded to the silyl group in the compound of the modifier having the nitrogen atom-containing group represented by the formula (A) is the alkali metal compound and / or the alkaline earth metal compound of the polymerization initiator. The range is preferably 0.6 times or more and 3.0 times or less, more preferably 0.8 times or more and 2.5 times or less, and 0.8 times or more and 2. It is more preferable that the range is 0 times or less. From the viewpoint of obtaining a sufficient denaturation rate, molecular weight and branched structure, the obtained conjugated diene-based polymer is preferably 0.6 times or more, and the polymer ends are coupled to each other to improve workability, resulting in a branched weight. In addition to obtaining a coalesced component, it is preferably 3.0 times or less from the viewpoint of denaturing agent cost.
The number of moles of the more specific polymerization initiator is preferably 3.0 times by mole or more, and more preferably 4.0 times by mole or more with respect to the number of moles of the modifier.

The modifier having a nitrogen atom-containing group represented by the formula (B) is not limited to the following, and for example, tris (3-trimethoxysilylpropyl) amine and tris (3-methyldimethoxysilylpropyl). Amines, tris (3-triethoxysilylpropyl) amines, tris (3-methyldiethoxysilylpropyl) amines, tris (trimethoxysilylmethyl) amines, tris (2-trimethoxysilylethyl) amines, and tris (4-trimethoxysilylethyl) amines. Trimethoxysilylbutyl) amines can be mentioned.
Among these, n, m, and l are all 3 from the viewpoint of reactivity and interaction between the functional group of the modifier and the inorganic filler such as silica, and from the viewpoint of processability. preferable. Preferred specific examples include tris (3-trimethoxysilylpropyl) amine and tris (3-triethoxysilylpropyl) amine.

The reaction temperature, reaction time, etc. when reacting the modifier having a nitrogen atom-containing group represented by the formula (B) with the polymerization active terminal are not particularly limited, but are 0 ° C. or higher and 120 ° C. or lower. It is preferable to react for 30 seconds or more.
The total number of moles of alkoxy groups bonded to the silyl group in the modifier compound represented by the formula (B) is 0.6 times or more and 3.0 times the number of moles of lithium constituting the above-mentioned polymerization initiator. The range is preferably as follows, more preferably 0.8 times or more and 2.5 times or less, and further preferably 0.8 times or more and 2.0 times or less. From the viewpoint of obtaining a sufficient denaturation rate, molecular weight and branched structure in the conjugated diene polymer, the value is preferably 0.6 times or more, and the polymer ends are coupled to each other to improve processability to obtain a branched polymer. In addition to obtaining the components, it is preferably 3.0 times or less from the viewpoint of the cost of the modifier.
The number of moles of the more specific polymerization initiator is preferably 4.0 times by mole or more, and more preferably 5.0 times by mole or more with respect to the number of moles of the modifier.

In the formula (C), A is preferably represented by any of the following general formulas (II) to (V).

(In formula (II), B ¹ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. B ¹ in the case of a plurality of carbon atoms is independent of each other. There.)

(In formula (III), B ² represents a single bond or a hydrocarbon group ^{having 1 to 20 carbon atoms, B 3} represents an alkyl group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10 carbon atoms. Shown. B ² and B ³ are independent when there are a plurality of them.)

(In formula (IV), B ⁴ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. B ⁴ in the case of a plurality of carbon atoms is independent of each other. There.)

(In the formula (V), B ⁵ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. B ⁵ in the case of a plurality of carbon atoms is independent of each other. There.)

In the formula (C), the modifier having a nitrogen atom-containing group when A is represented by the formula (II) is not limited to the following, but for example, 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-ethoxysilyl) Propyl) amine, bis (3-triethoxysilylpropyl)-[3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] amine, bis [3- (2,2-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 -Propyldiamine, bis (3-trimethoxysilylpropyl) -bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] -1,3-propanediamine, tris [3-( 2,2-Dimethoxy-1-aza-2-silacyclopentane) propyl]-(3-trimethoxysilylpropyl) -1,3-propanediamine, tetrakis [3- (2,2-dimethoxy-1-aza-) 2-Silacyclopentane) propyl] -1,3-propanediamine, 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-azacyclopentane) propyl]-(3- (3- Trimethoxysilylpropyl)-[3- (1-Metoki) Si-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-propanediamine, tris [3- (2,2-dimethoxy-1-aza-2-azacyclopentane) propyl]- [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-propanediamine, tetrakis (3-triethoxysilylpropyl) -1,3-propanediamine, tris (3-Triethoxysilylpropyl)-[3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] -1,3-propanediamine, bis (3-triethoxysilylpropyl) -bis [3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] -1,3-propanediamine, tris [3- (2,2-diethoxy-1-aza-2-silacyclopentane) ) Propyl]-(3-triethoxysilylpropyl) -1,3-propanediamine, tetrakis [3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] -1,3-propanediamine , Tris (3-triethoxysilylpropyl)-[3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-propanediamine, bis (3-triethoxysilyl) Propyl)-[3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl]-[3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-Propyldiamine, 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-azacyclopentane) 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, 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, Tris (3-trimethoxysilylpropyl)-[3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-bisaminomethylcyclohexane, Bis (3-trimethoxysilylpropyl)-[3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl]-[3- (1-methoxy-2-trimethylsilyl-1-sila-2) -Azacyclopentane) propyl] -1,3-bisaminomethylcyclohexane, bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl]-(3-trimethoxysilylpropyl)- [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-bisaminomethylcyclohexane, Tris [3- (2,2-dimethoxy-1-aza-2) -Silacyclopentane) propyl]-[3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-bisaminomethylcyclohexane, tetrakis (3-triethoxysilylpropyl) ) -1,3-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-azasik) Lopentan) 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-silacyclo) Pentan) Propyl]-(3-Triethoxysilylpropyl)-[3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3-bisaminomethylcyclohexane, Tris [ 3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl]-[3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] -1,3 Included are -bisaminomethylcyclohexane, tetrakis (3-trimethoxysilylpropyl) -1,6-hexamethylenediamine, and pentax (3-trimethoxysilylpropyl) -diethylenetriamine.

In the formula (C), the modifier having a nitrogen atom-containing group when A is represented by the formula (III) is not limited to the following, but for example, 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-triethoxysilyl) Propyl) -methyl-1,3-propanediamine, bis (2-triethoxysilylpropyl)-[3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] -methyl-1,3 - propanediamine, bis [3- (2,2-diethoxy-1-aza-2-silacyclopentane) propyl] - (3-triethoxysilylpropyl) - methyl-1,3-propanediamine, N ^1, N ¹ '-(Propyl-1,3-diyl) bis (N ¹ -methyl-N ³ , N ³ -bis (3- (trimethoxysilyl) propyl) -1,3-propanediamine), and N ^1- ( 3- (bis (3- (trimethoxysilyl) propyl) amino) propyl) -N ¹ - methyl -N ³ - (3- (methyl (3- (trimethoxysilyl) propyl) amino) propyl) -N ³ - (3- (Trimethoxysilyl) propyl) -1,3-propanediamine can be mentioned.

In the formula (C), the modifier having a nitrogen atom-containing group when A is represented by the formula (IV) is not limited to the following, but for example, tetrakis [3- (2,2-dimethoxy). -1-aza-2-silacyclopentane) propyl] silane, tris [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl]-(3-trimethoxysilylpropyl) silane, tris [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl]-[3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl] silane, bis (3-Trimethoxysilylpropyl) -bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] silane, (3-trimethoxysilyl)-[3- (1-methoxy-) 2-trimethylsilyl-1-sila-2-azacyclopentane) -bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] silane, 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-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-aza) Cyclopentane) propyl] silane.

In the formula (C), the modifier having a nitrogen atom-containing group when A is represented by the formula (V) is not limited to the following, but for example, 3-tris [2- (2,2). -Dimethoxy-1-aza-2-silacyclopentane) ethoxy] Cyril-1- (2,2-dimethoxy-1-aza-2-silacyclopentane) propane, and 3-tris [2- (2,2-) Dimethoxy-1-aza-2-silacyclopentane) ethoxy] silyl-1-trimethoxysilylpropane can be mentioned.

In the formula (C), A is preferably represented by the formula (II) or the formula (III), and k represents 0.
Such a modifier having a nitrogen atom-containing group tends to be easily available, and has more excellent wear resistance and low hysteresis loss performance when a conjugated diene-based polymer is used as a vulcanized product. It tends to be. The modifier having such a nitrogen atom-containing group is not limited to the following, but for example, 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-dimethoxy-1-aza-2-silacyclopentane) propyl] -1,3-propanediamine , Tetrax (3-trimethoxysilylpropyl) -1,3-propanediamine, Tetrax (3-trimethoxysilylpropyl) -1,3-bisaminomethylcyclohexane, Tris (3-trimethoxysilylpropyl) -methyl-1 , 3-Propyldiamine, and bis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl]-(3-trismethoxysilylpropyl) -methyl-1,3-propanediamine. Be done.

In the formula (C), A is more preferably represented by the formula (II) or the formula (III), k represents 0, and in the formula (II) or the formula (III), a is 2 to 10 Indicates an integer of.
As a result, the wear resistance and the low hysteresis loss performance at the time of vulcanization tend to be more excellent.
Modification agents having such a nitrogen atom-containing group are not limited to the following, but for example, tetrakis [3- (2,2-dimethoxy-1-aza-2-silacyclopentane) propyl] -1, 3-Propyldiamine, tetrax (3-trimethoxysilylpropyl) -1,3-propanediamine, tetrax (3-trimethoxysilylpropyl) -1,3-bisaminomethylcyclohexane, and N ^1- (3- (bis) (3- (trimethoxysilyl) propyl) amino) propyl) -N ¹ - methyl -N ³ - (3- (methyl (3- (trimethoxysilyl) propyl) amino) propyl) -N ³ - (3- ( Examples thereof include trimethoxysilyl) propyl) -1,3-propanediamine.

The amount of the compound represented by the above formula (C) as a modifier having a nitrogen atom-containing group is such that the number of moles of the conjugated diene polymer to the number of moles of the modifier is a desired stoichiometric ratio. As described above, the conjugated diene polymer can be adjusted to react with the modifier, which tends to achieve the desired star-shaped hyperbranched structure.
The specific number of moles of the conjugated diene polymer is preferably 5.0 times or more, more preferably 6.0 times or more, based on the number of moles of the modifier.
In this case, in the formula (C), the number of functional groups ((m-1) × i + p × j + k) of the modifier is preferably an integer of 5 to 10, and more preferably an integer of 6 to 10.

In the conjugated diene-based polymer of the present embodiment, the ratio of the nitrogen atom-containing polymer in the conjugated diene-based polymer is represented by a modification rate.
The modification rate is preferably 60% by mass or more, more preferably 65% by mass or more, still more preferably 70% by mass or more, still more preferably 75% by mass or more, still more preferably 80% by mass or more.
By setting the modification rate to 60% by mass or more, the processability of the vulcanized product tends to be excellent, and the wear resistance and the low hysteresis loss performance of the vulcanized product tend to be excellent.

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

In the conjugated diene-based polymer of the present embodiment, the conjugated diene portion may be hydrogenated.
The method for hydrogenating the conjugated diene portion of the conjugated diene-based polymer is not particularly limited, and a known method can be used.
As a suitable hydrogenation method, a method of hydrogenating by blowing gaseous hydrogen into the polymer solution in the presence of a catalyst can be mentioned.
The catalyst is not particularly limited, but for example, a heterogeneous catalyst such as a catalyst in which a noble metal is supported on a porous inorganic substance; a catalyst in which salts such as nickel and cobalt are solubilized and reacted with organic aluminum and the like, titanosen and the like. A homogeneous catalyst such as a catalyst using the metallocene of the above can be mentioned. Among these, the titanocene catalyst is preferable from the viewpoint that mild hydrogenation conditions can be selected.
Further, hydrogenation of the aromatic group can be carried out by using a supported catalyst of a noble metal.

The hydrogenation catalyst is not limited to the following, but for example, (1) a support type heterogeneous hydrogenation in which a metal such as Ni, Pt, Pd, Ru is supported on carbon, silica, alumina, Keisou soil, or the like. A catalyst, a so-called Cheegler-type hydrogenated catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as an acetylacetone salt and a reducing agent such as organic aluminum, (3) Ti, Ru, Examples thereof include so-called organic metal complexes such as organic metal compounds such as Rh and Zr. Further, the hydrogenation catalyst is not particularly limited, but for example, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-377970, Special Fair 1- Also mentioned are known hydrogenation catalysts described in Japanese Patent Application Laid-Open No. 53851, Japanese Patent Application Laid-Open No. 2-9041 and Japanese Patent Application Laid-Open No. 8-109219. Preferred hydrogenation catalysts include reaction mixtures of titanocene compounds and reducing organometallic compounds.

In the method for producing a conjugated diene-based polymer of the present embodiment, a deactivating agent, a neutralizing agent, or the like may be added to the polymer solution after the coupling step, if necessary.
The inactivating agent is not limited to the following, and examples thereof include water; alcohols such as methanol, ethanol, and isopropanol.
The neutralizing agent is not limited to the following, but for example, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of carboxylic acids having 9 to 11 carbon atoms and mainly 10 branches). Acid: An aqueous solution of an inorganic acid and carbonic acid gas can be mentioned.

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

From the viewpoint of further improving the control of the Mooney viscosity of the conjugated diene polymer of the present embodiment measured at 100 ° C., the productivity of the conjugated diene polymer, and the processability of a rubber composition containing a filler and the like. Therefore, if necessary, a softening agent for rubber can be added.
The softening agent for rubber is not particularly limited, and examples thereof include extension oil, liquid rubber, and resin.
The method of adding the softening agent for rubber to the conjugated diene polymer is not limited to the following, but the softening agent for rubber is added to the conjugated diene polymer solution, mixed, and the weight containing the softening agent for rubber is added. A method of removing the solvent from the combined solution is preferable.

Preferred spreading oils include, for example, aroma oil, naphthenic oil, paraffin oil and the like. Among these, an aroma substitute oil having a polycyclic aromatic (PCA) component of 3% by mass or less according to the IP346 method is preferable from the viewpoint of environmental safety, prevention of oil bleeding, and wet grip characteristics. Examples of the aroma substitute oil include TDAE (Treatd Distillate Aromatic Extracts) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), MES (Mild Extraction Plastic), and RA.

Preferred liquid rubber is not limited to the following, but for example, liquid polybutadiene, liquid styrene? Butazin rubber and the like can be mentioned.
As an effect when liquid rubber is added, in addition to improving workability when a rubber composition containing a conjugated diene polymer and a filler is prepared, the vulcanization transition temperature of the rubber composition is set to a lower temperature side. Being able to shift tends to improve wear resistance, low hysteresis loss, and low temperature characteristics when made into a vulcanized product.

Preferred resins are not limited to the following, but are, for example, aromatic petroleum resins, kumaron-inden resins, terpene resins, rosin derivatives (including tung oil resins), tall oils, tall oil derivatives, and rosin ester resins. , Natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenol resins, p-tert-butylphenol-acetylene resins, phenol-formaldehydes. Resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, aromatic hydrocarbon resins, aromatic petroleum resins, hydride aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydride hydrocarbon resins , Hydrocarbon resin, hydride tung oil resin, hydride oil resin, ester of hydride oil resin and monofunctional or polyfunctional alcohol and the like.
These resins may be used alone or in combination of two or more. When hydrogenating, all unsaturated groups may be hydrogenated or some may be left.

As an effect when the resin is added, in addition to improving the processability when the rubber composition is a mixture of the conjugated diene polymer and the filler and the like, the breaking strength when the vulcanized product is used is improved. There is a tendency, and the vulcanization transition temperature of the rubber composition can be shifted to the high temperature side, so that the wet skid resistance tends to be improved.

The amount of the spreading oil, liquid rubber, resin, or the like added as the softening agent for rubber is not particularly limited, but is preferably 1 part by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the conjugated diene polymer of the present embodiment. , More preferably 5 parts by mass or more and 50 parts by mass or less, and further preferably 10 parts by mass or more and 37.5 parts by mass or less.

When a softening agent for rubber is added within the above range, the Mooney viscosity of the conjugated diene polymer measured at 100 ° C. can be controlled to 40 or more and 170 or less, and the rubber composition containing the conjugated diene polymer and a filler or the like can be controlled. The processability of the product tends to be good, and the fracture strength and wear resistance of the vulcanized product tend to be good.

[Solvent removal step]
In the method for producing a conjugated diene-based polymer of the present embodiment, a known method can be used as a method for obtaining the obtained conjugated diene-based polymer from the polymer solution. The method is not particularly limited, but for example, after separating the solvent by steam stripping or the like, the polymer is filtered off, and further dehydrated and dried to obtain the polymer, concentrated in a flushing tank, and then concentrated. Further, a method of devolatile with a vent extruder or the like and a method of directly devolatile with a drum dryer or the like can be mentioned.

(Rubber composition)
The rubber composition of the present embodiment contains a rubber component and silica of 30 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the rubber component, and the nitrogen adsorption specific surface area of the silica is 180 m ² / g or more. ..
Further, the rubber component contains 10% by mass or more of the above-mentioned conjugated diene polymer with respect to the total amount of the rubber component from the viewpoint of improving fuel efficiency, workability, and abrasion resistance.

<Silica>
The rubber composition of the present embodiment contains silica having a nitrogen adsorption specific surface area of 180 m ² / g or more.
Silica having a nitrogen adsorption specific surface area in the above range easily self-aggregates and is difficult to disperse, so that the balance between wear resistance, fracture strength, low hysteresis loss, and wet skid resistance when made into a vulcanized product deteriorates. There is a tendency.
On the other hand, the conjugated diene polymer of the present embodiment having the above-mentioned Mooney viscosity, Mooney relaxation rate, and degree of branching has a highly branched structure. A material having a highly branched structure lowers the viscosity of the rubber composition when shearing is applied during kneading, so that the dispersion of silica can be further improved.
The rubber composition of the present embodiment contains the above-mentioned conjugated diene polymer in an amount of 10% by mass or more in the rubber component. As a result, the silica dispersibility can be improved. The amount of the conjugated diene polymer is 10% by mass or more, preferably 20% by mass or more, more preferably 50% by mass or more, and further preferably 80% by mass or more with respect to the total amount of the rubber components.
The conjugated diene polymer has a high function of dispersing silica and mixes well with the rubber component, so that it functions like a so-called "compatibility agent" for dispersing silica in the entire rubber component. Therefore, even if the ratio in the rubber component is about 10% by mass, the effect of improving the dispersibility of silica is sufficiently exhibited, and as a rubber composition, the abrasion resistance and fracture strength of the vulcanized product accompanying the dispersion of silica are exhibited. And the effect of improving the balance between low hysteresis loss and wet skid resistance is recognized.

The rubber composition of the present embodiment tends to be more excellent in processability when it is made into a vulcanized product by dispersing silica satisfying the above-mentioned requirements, and wear resistance and breaking strength when it is made into a vulcanized product. And it tends to be superior due to the balance between low hysteresis loss property and wet skid resistance.

(Rubber component)
As the rubber component contained in the rubber composition of the present embodiment, a rubber-like polymer other than the above-mentioned conjugated diene-based polymer of the present embodiment (hereinafter, simply referred to as “rubber-like polymer”) is referred to as the above-mentioned conjugated diene. It can be used in combination with a system polymer.
Such rubber-like polymers are not limited to the following, but for example, a conjugated diene polymer or a hydrogenated product thereof, a random copolymer of a conjugated diene compound and a vinyl aromatic compound, or a hydrogenated product thereof. Examples thereof include block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, non-diene polymers, and natural rubbers.

Specific rubber-like polymers are not limited to the following, but for example, butadiene rubber or its hydrogen additive, isoprene rubber or its hydrogen additive, styrene-butadiene rubber or its hydrogen additive, styrene-butadiene block. Examples thereof include a copolymer or a hydrogenated product thereof, a styrene-based elastomer such as a styrene-isoprene block copolymer or a hydrogenated product thereof, an acrylonitrile-butadiene rubber or a hydrogenated product thereof.
The non-diene polymer is not limited to the following, but is, for example, an olefin-based polymer such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber. Elastomer, 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 Can be mentioned.
The natural rubber is not limited to the following, and examples thereof include smoked sheets RSS3 to 5, SMR, and epoxidized natural rubber.
The various rubber-like polymers described above may be modified rubbers to which functional groups having polarities such as hydroxyl groups and amino groups are added. When used for tires, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber are preferably used.

The weight average molecular weight of the rubber-like polymer is preferably 2000 or more and 20000,000 or less, and more preferably 5000 or more and 1500,000 or less, from the viewpoint of the balance between performance and processing characteristics. Further, a rubber-like polymer having a low molecular weight, so-called liquid rubber, can also be used. These rubber-like polymers may be used alone or in combination of two or more.

When the rubber composition of the present embodiment is a rubber composition containing the above-mentioned conjugated diene polymer and the rubber-like polymer, the content ratio (mass ratio) of the above-mentioned conjugated diene polymer to the rubber-like polymer. (The above-mentioned conjugated diene polymer / rubber-like polymer) is 10/90 or more and 100/0 or less, preferably 20/80 or more and 90/10 or less, and 50/50 or more and 80/20 or less. preferable.
Therefore, the rubber component preferably contains the above-mentioned conjugated diene polymer in an amount of 10 parts by mass or more and 100 parts by mass or less, and more preferably 20 parts by mass or more and 90 parts by mass or more, based on the total amount (100 parts by mass) of the rubber component. It contains less than or equal to 50 parts by mass, more preferably 50 parts by mass or more and 80 parts by mass or less.
When the content ratio of (the above-mentioned conjugated diene polymer / rubber-like polymer) is within the above range, the vulcanized product has excellent wear resistance and fracture strength, and has low hysteresis loss and wet skid resistance. The balance of is also satisfied.

(filler)
As the filler contained in the rubber composition of the present embodiment, the following can be added in addition to the silica having the specific nitrogen adsorption specific surface area.
For example, silica-based inorganic fillers other than "silica whose nitrogen adsorption specific surface area meets the above requirements" (hereinafter, simply referred to as other silica-based inorganic fillers), carbon black, metal oxides, metal hydroxides. Can be mentioned. Among these, carbon black is preferable.
The filler may be silica alone or in combination of two or more.

The content of silica having a nitrogen adsorption specific surface area of 180 m ² / g or more in the rubber composition of the present embodiment is 30 parts by mass or more and 150 parts by mass with respect to 100 parts by mass of the rubber component containing the above-mentioned conjugated diene polymer. It is a mass part.
By setting the content of the specific silica in the above range, it is excellent in steering stability and low hysteresis loss when the tire is used. From the viewpoint of improving steering stability, 50 parts by mass or more is preferable, and 60 parts by mass or more is more preferable. Further, from the viewpoint of improving the low hysteresis loss property, 120 parts by mass or less is preferable, and 90 parts by mass or less is more preferable.

The other silica-based inorganic filler is not particularly limited, and known ones can be used, but _{solid particles containing SiO 2} or Si ₃ Al as a constituent unit are preferable, and SiO ₂ or Si ₃ Al is formed. Solid particles contained as the main component of the unit are more preferable. Here, the main component means a component contained in the silica-based inorganic filler in an amount of 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more.

Specific other silica-based inorganic fillers are not limited to the following, but include, for example, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Can be mentioned.
Further, a silica-based inorganic filler having a hydrophobic surface, a mixture of a silica-based inorganic filler and a non-silica-based inorganic filler can also be mentioned.
Among these, silica and glass fiber are preferable, and silica is more preferable, from the viewpoint of strength, abrasion resistance and the like.
Examples of silica include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferable from the viewpoint of improving the breaking strength and the balance of wet skid resistance.

The rubber composition of the present embodiment may contain carbon black. The carbon black is not limited to the following, and examples thereof include carbon blacks of each class such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area of 50 m ² / g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL / 100 g or less is preferable.

In the rubber composition of the present embodiment, the content of carbon black is preferably 0.5 parts by mass or more and 100 parts by mass or less, preferably 3.0 parts by mass, with respect to 100 parts by mass of the rubber component containing the conjugated diene polymer. More than 100 parts by mass is more preferable, and 5.0 parts by mass or more and 50 parts by mass or less is further preferable. In the rubber composition of the present embodiment, the content of carbon black is 0.5 with respect to 100 parts by mass of the rubber component from the viewpoint of exhibiting the performance required for applications such as tires such as dry grip performance and conductivity. It is preferably 100 parts by mass or more, and preferably 100 parts by mass or less with respect to 100 parts by mass of the rubber component from the viewpoint of dispersibility.

(Metal oxide, metal hydroxide)
The conjugated diene-based polymer composition of the present embodiment may contain a metal oxide or a metal hydroxide in addition to the silica-based inorganic filler or carbon black.
The metal oxide refers to solid particles having the chemical formula MxOy (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) as a main component of the constituent unit. .. The metal oxide is not limited to the following, and examples thereof include alumina, titanium oxide, magnesium oxide, and zinc oxide.
Metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydride.

(Silane coupling agent)
The rubber composition of the present embodiment may contain a silane coupling agent. The silane coupling agent has a function of closely interacting with the rubber component and the inorganic filler, and has an affinity or binding group for each of the rubber component and the silica-based inorganic filler. , A compound having a sulfur-bonded moiety and an alkoxysilyl group or silanol group moiety in one molecule is preferable. Such compounds are not particularly limited, but are, for example, bis- [3- (triethoxysilyl) -propyl] -tetrasulfide, bis- [3- (triethoxysilyl) -propyl] -disulfide, bis- [. 2- (Triethoxysilyl) -ethyl] -tetrasulfide can be mentioned.
In the rubber composition of the present embodiment, the content of the silane coupling agent is preferably 0.1 part by mass or more and 30 parts by mass or less, and 0.5 parts by mass or more and 20 parts by mass with respect to 100 parts by mass of the above-mentioned inorganic filler. More preferably, it is 1.0 part by mass or less, and further preferably 1.0 part by mass or more and 15 parts by mass or less. When the content of the silane coupling agent is in the above range, the effect of the addition by the silane coupling agent tends to be more remarkable.

(Rubber softener)
From the viewpoint of improving the processability, the rubber composition of the present embodiment contains a rubber softener in a step separate from the rubber softener added to the conjugated diene polymer and other rubber polymers. It may be added.
The amount of the softening agent for rubber added is 100 parts by mass of the rubber component containing the above-mentioned conjugated diene-based polymer, which is previously contained in the above-mentioned conjugated diene-based polymer or other rubber-like polymer for rubber. It is represented by the amount containing the softening agent and the total amount of the softening agent for rubber added when the rubber composition is prepared.
As the softener for rubber, mineral oil or a liquid or low molecular weight synthetic softener is suitable.
Mineral oil-based rubber softeners called process oils or extender oils used to soften, increase volume, and improve processability of rubbers are mixtures of aromatic rings, naphthenic rings, and paraffin chains. , The paraffin chain having 50% or more of carbon atoms in the total carbon is called paraffin-based, and the paraffin ring having 30% or more and 45% or less of all carbon atoms is naphthen-based, and the total number of aromatic carbon atoms is all. Those that occupy more than 30% of carbon are called aromatic systems. When the conjugated diene-based polymer of the present embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, a softening agent for rubber to be used having an appropriate aromatic content is familiar with the copolymer. Is preferable because it tends to be good.
In the rubber composition of the present embodiment, the content of the softening agent for rubber is preferably 0 parts by mass or more and 100 parts by mass or less, and more preferably 10 parts by mass or more and 90 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferably, it is 30 parts by mass or more and 90 parts by mass or less. When the content of the softener for rubber is 100 parts by mass or less with respect to 100 parts by mass of the rubber component, bleed-out is suppressed and stickiness on the surface of the rubber composition tends to be suppressed.

[Manufacturing method of rubber composition]
The method for mixing the conjugated diene polymer with other rubber-like polymers, silica-based inorganic filler, carbon black and other fillers, silane coupling agent, rubber softener, and other additives is as follows. Although not limited to, for example, a melt-kneading method using a general mixer such as an open roll, a rubbery mixer, a kneader, a single-screw screw extruder, a twin-screw screw extruder, or a multi-screw screw extruder, and melting each component. After mixing, a method of heating and removing the solvent can be mentioned. Of these, the melt-kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferable from the viewpoint of productivity and good kneading. Further, any of a method of kneading the rubber component and other fillers, a silane coupling agent, and an additive at once, and a method of mixing them in a plurality of times can be applied.

The rubber composition of the present embodiment may be a vulcanized composition that has been vulcanized with a vulcanizing agent. Examples of the sulfide agent include, but are not limited to, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, high molecular weight polysulfur compounds and the like. In the rubber composition of the present embodiment, the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, and 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component. More preferred. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is preferably 120 ° C. or higher and 200 ° C. or lower, more preferably 140 ° C. or higher and 180 ° C. or lower.

At the time of vulcanization, a vulcanization accelerator may be used if necessary. Conventionally known materials can be used as the vulcanization accelerator, and the vulcanization accelerator is not limited to the following, but is, for example, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, and thiazole-based. , Thiourea-based and dithiocarbamate-based vulcanization accelerators. The vulcanization aid is not limited to the following, and examples thereof include zinc oxide and stearic acid. The content of the vulcanization accelerator is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the rubber component.

The rubber composition of the present embodiment includes other softeners and fillers other than those described above, heat-resistant stabilizers, antistatic agents, weather-resistant stabilizers, anti-aging agents, as long as the object of the present embodiment is not impaired. Various additives such as colorants and lubricants may be used. As the other softener, a known softener can be used. Specific examples of other fillers include, but are not limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. Known materials can be used as the heat-resistant stabilizer, antistatic agent, weather-resistant stabilizer, anti-aging agent, colorant, and lubricant.

〔tire〕
The rubber composition of this embodiment is suitably used as a rubber composition for tires. That is, the tire of the present embodiment is made by using a conjugated diene-based polymer composition.

The rubber composition for tires is not limited to the following, but for example, various tires such as fuel-saving tires, all-season tires, high-performance tires, and studless tires: tires such as treads, carcass, sidewalls, and beads. It can be used for parts. In particular, the rubber composition for tires has an excellent balance of wear resistance, breaking strength, low hysteresis loss property and wet skid resistance when made into a vulcanized product, and thus is suitable for fuel-efficient tires and high-performance tires. It is preferably used for treads.

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.
Various physical properties in Examples and Comparative Examples were measured by the methods shown below.
In the following, the conjugated diene polymer coupled with the modifier is referred to as "coupling polymer", and the conjugated diene polymer not coupled with the modifier is referred to as "conjugated diene polymer before the coupling reaction". It is referred to as "polymer" or "conjugated diene polymer". Further, these may be collectively referred to as "conjugated diene polymer".

[Physical characteristic measurement method]
(Physical characteristics 1) Polymer Mooney viscosity A conjugated diene polymer before the coupling reaction or a conjugated diene polymer coupled with a nitrogen atom-containing modifier (hereinafter, also referred to as "coupling conjugated diene polymer"). The Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used as a sample, and the Mooney viscosity was measured using an L-shaped rotor in accordance with ISO 289.
The measurement temperature was 110 ° C. when the conjugated diene polymer before the coupling reaction was used as a sample, and 100 ° C. when the coupled conjugated diene polymer was used as a sample.
For the sample not subjected to the coupling step, the measured was carried out at 110 ° C. and 100 ° C. using the produced conjugated diene polymer as a sample.
First, the sample was preheated at the test temperature for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to obtain Mooney viscosity (ML _{(1 + 4)} ).

(Physical characteristics 2) Mooney relaxation rate Using each conjugated diene polymer produced as described below as a sample, using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.), it conforms to ISO 289 and is L-shaped. After measuring the Mooney viscosity using the rotor, the rotation of the rotor is stopped immediately, and the torque every 0.1 seconds for 1.6 seconds to 5 seconds after the stop is recorded in Mooney units, and the torque and time (seconds) Was calculated in both logarithmic plots, and the absolute value was taken as the Mooney relaxation rate (MSR).

(Physical characteristics 3) Degree of branching (Bn)
The degree of branching (Bn) of the conjugated diene polymer was measured as follows by the GPC-light scattering method with a viscosity detector.
A gel permeation chromatography (GPC) measuring device (trade name "GPCmax VE" manufactured by Malvern) in which three columns using a polystyrene gel as a filler are connected using each conjugated diene polymer produced as described below as a sample. -2001 ") is used to measure using three detectors connected in the order of light scattering detector, RI detector, viscosity detector (trade name" TDA305 "manufactured by Polymer), and standard. Based on polystyrene, the absolute molecular weight was determined from the results of the light scattering detector and RI detector, and the intrinsic viscosity was determined from the results of the RI detector and viscosity detector.
The linear polymer was used according to the intrinsic viscosity [η] = -3.883M ^0.771, and the shrinkage factor (g') as the ratio of the intrinsic viscosity corresponding to each molecular weight was calculated. In the formula, M represents the absolute molecular weight.
Then, using the obtained contraction factor (g'), the degree of bifurcation (Bn) defined as g'= 6Bn / [(Bn + 1) (Bn + 2)] was calculated.
As the eluent, tetrahydrofuran containing 5 mmol / L triethylamine (hereinafter, also referred to as “THF”) was used.
The column was used by connecting the trade names "TSKgel G4000HXL", "TSKgel G5000HXL", and "TSKgel G6000HXL" manufactured by Tosoh Corporation.
20 mg of the sample for measurement was dissolved in 10 mL of THF to prepare a measurement solution, and 100 μL of the measurement solution was injected into a GPC measuring device to measure under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 1 mL / min.

(Physical characteristics 4) Molecular weight measurement condition 1:
Using each conjugated diene polymer produced as described below as a sample, a GPC measuring device (trade name "HLC-8320GPC" manufactured by Tosoh Corporation) in which three columns using a polystyrene gel as a filler are connected is used. Then, the chromatogram was measured using an RI detector (trade name "HLC8020" manufactured by Tosoh Corporation), and the weight average molecular weight (Mw) and the number average molecular weight (Mw) and the number average molecular weight (Mw) were measured based on the calibration curve obtained using standard polystyrene. Mn) and the molecular weight distribution (Mw / Mn) were determined.
The eluent used was THF (tetrahydrofuran) containing 5 mmol / L triethylamine. As the column, three Tosoh product names "TSKgel SuperMultipore HZ-H" were connected, and a Tosoh product name "TSKguardcolum SuperMP (HZ) -H" was connected and used as a guard column in front of the column.
10 mg of the sample for measurement was dissolved in 10 mL of THF to prepare a measurement solution, and 10 μL of the measurement solution was injected into a GPC measuring device and measured under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 0.35 mL / min.
Among the various samples measured under the above measurement condition 1, the sample having a molecular weight distribution (Mw / Mn) value of less than 1.6 was measured again under the following measurement condition 2.
The measurement was performed under measurement condition 1, and the sample having a molecular weight distribution value of 1.6 or more was measured under measurement condition 1.
Measurement condition 2:
Using each conjugated diene polymer produced as described below as a sample, a chromatogram was measured using a GPC measuring device in which three columns using polystyrene gel as a filler were connected, and standard polystyrene was used. The weight average molecular weight (Mw) and the number average molecular weight (Mn) were determined based on the calibration curve.
The eluent used was THF containing 5 mmol / L triethylamine. As the column, a guard column: a product name "TSKguard color SuperH-H" manufactured by Tosoh Corporation, and a column: a product name "TSKgel SuperH5000", "TSKgel SuperH6000", "TSKgel SuperH7000" manufactured by Tosoh Corporation were used.
An RI detector (trade name "HLC8020" manufactured by Tosoh Corporation) was used under the conditions of an oven temperature of 40 ° C. and a THF flow rate of 0.6 mL / min. 10 mg of the sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into a GPC measuring device for measurement.
The measurement was performed under measurement condition 1, and the sample whose molecular weight distribution value was less than 1.6 was measured under measurement condition 2.

(Physical characteristics 5) Modification rate The modification rate of each conjugated diene polymer produced as described below was measured by the column adsorption GPC method as follows.
The measurement was carried out by applying the property of adsorbing the modified basic polymer component to a GPC column using a coupling-conjugated diene polymer as a sample and using a silica gel as a filler.
The amount of adsorption of the sample and the sample solution containing the low molecular weight internal standard polystyrene to the silica-based column was measured from the difference between the chromatogram measured on the polystyrene-based column and the chromatogram measured on the silica-based column, and the modification rate was determined. I asked.
Specifically, it is as shown below. Further, for a sample measured under the measurement condition 1 of (Physical Properties 4) above and whose molecular weight distribution value is 1.6 or more, the following measurement condition 3 and its molecular weight distribution value is less than 1.6. The existing sample was measured under the following measurement condition 4.
Preparation of sample solution:
10 mg of sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution.
Measurement condition 3: GPC measurement condition using polystyrene column:
Using the trade name "HLC-8320GPC" manufactured by Tosoh Corporation, using 5 mmol / L THF containing triethylamine as an eluent, 10 μL of the sample solution was injected into the apparatus, the column oven temperature was 40 ° C., and the THF flow rate was 0.35 mL /. Chromatograms were obtained using an RI detector under the condition of minutes. As the column, three Tosoh product names "TSKgel SuperMultipore HZ-H" were connected, and a Tosoh product name "TSKguardcolum SuperMP (HZ) -H" was connected and used as a guard column in front of the column.
Measurement condition 4: Using 5 mmol / L THF containing triethylamine as an eluent, 20 μL of the sample solution was injected into the apparatus for measurement. As the column, a guard column: a product name "TSKguard color SuperH-H" manufactured by Tosoh Corporation, and a column: a product name "TSKgel SuperH5000", "TSKgel SuperH6000", "TSKgel SuperH7000" manufactured by Tosoh Corporation were used. Chromatograms were obtained by measurement using an RI detector (HLC8020 manufactured by Tosoh Corporation) under the conditions of a column oven temperature of 40 ° C. and a THF flow rate of 0.6 mL / min.
GPC measurement conditions using a silica-based column:
Using the trade name "HLC-8320GPC" manufactured by Tosoh Corporation, using THF as an eluent, injecting 50 μL of the sample solution into the apparatus, RI at a column oven temperature of 40 ° C. and a THF flow rate of 0.5 ml / min. Chromatograms were obtained using a detector. The column is used by connecting the product names "Zorbox PSM-1000S", "PSM-300S", and "PSM-60S", and the product name "DIOL 4.6 x 12.5 mm 5 micron" is used as a guard column in front of the column. Used by connecting.
Calculation method of denaturation rate:
Samples with the total peak area of the chromatogram using a polystyrene column as 100, the peak area of the sample as P1, the peak area of standard polystyrene as P2, and the total peak area of the chromatogram using a silica column as 100. The modification rate (%) was calculated from the following formula, where the peak area of the standard polystyrene was P3 and the peak area of the standard polystyrene was P4.
Degeneration rate (%) = [1- (P2 × P3) / (P1 × P4)] × 100
(However, P1 + P2 = P3 + P4 = 100)

(Physical characteristics 6) Amount of bound styrene Using each conjugated diene-based polymer produced as described below, which does not contain a softener for rubber, as a sample, 100 mg of the sample is made up to 100 mL with chloroform, dissolved, and used as a measurement sample. bottom.
The amount of bonded styrene (mass%) with respect to 100% by mass of the coupling-conjugated diene polymer as a sample was measured by the amount of ultraviolet absorption wavelength (around 254 nm) absorbed by the phenyl group of styrene (Measuring device: Shimadzu Seisakusho). Spectral photometer "UV-2450" manufactured by the company.

(Physical characteristics 7) Microstructure of butadiene part (1,2-vinyl bond amount)
Each conjugated diene-based polymer produced as described below, which does not contain a softening agent for rubber, was used as a sample, and 50 mg of the sample was dissolved in 10 mL of carbon disulfide to prepare a measurement sample. Using a solution cell, the infrared spectrum was ^{measured in the range of 600 to 1000 cm -1} , and the absorbance at a predetermined wave number was used by Hampton's method (method described in RR Hampton, Analytical Chemistry 21,923 (1949)). The microstructure of the butadiene portion, that is, the amount of 1,2-vinyl bond (mol%) was determined according to the calculation formula of (Measuring device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

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

[Conjugated diene polymer]
(Coupling Conjugated Diene Polymer (Sample 1))
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily water-removed 1,3-butadiene was mixed under the conditions of 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min to obtain a mixed solution. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactive group, n-butyllithium for the residual impurity inactivation treatment was added at 0.103 mmol / min, mixed, and then added to the bottom of the reactive group. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.081 mmol / min and n-butyllithium as a polymerization initiator is vigorously mixed at a rate of 0.143 mmol / min1. It was supplied to the bottom of the basic reactor and the temperature inside the reactor was maintained at 67 ° C.
The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 70 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, while copolymerizing 1,3-butadiene and styrene, trimethoxy (4-vinylphenyl) silane as a branching agent from the bottom of the second reactive group (in the table, "BS". -1 ”) was added at a rate of 0.0190 mmol / min, and a polymerization reaction and a branching reaction were carried out to obtain a conjugated diene-based polymer having a main chain branched structure. Further, when the polymerization reaction and the branching reaction are stable, a small amount of the conjugated diene polymer solution before the addition of the coupling agent is extracted, and an antioxidant (BHT) is added so as to be 0.2 g per 100 g of the polymer, and then the solvent is used. Was removed, and the Mooney viscosity at 110 ° C. and various molecular weights were measured. The physical characteristics are shown in Table 1.
Next, tetraethoxysilane (abbreviated as "A" in the table) was continuously added as a coupling agent to the polymer solution flowing out from the outlet of the reactor at a rate of 0.0480 mmol / min, and statically added. The mixture was mixed using a mixer and the coupling reaction was carried out. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes and the temperature was 68 ° C., until the temperature in the polymerization step and the addition of the coupling agent. The difference from the temperature of was 2 ° C. A small amount of the conjugated diene polymer solution after the coupling reaction was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed to remove the bound styrene amount (physical characteristics 6) and the amount of bound styrene. The microstructure of the butadiene part (1,2-vinyl bond amount: physical properties 7) was measured. The measurement results are shown in Table 1.
Next, an antioxidant (BHT) was continuously added to the coupling-reacted polymer solution at 0.055 g / min (n-hexane solution) so as to be 0.2 g per 100 g of the polymer, and coupling was performed. The reaction was terminated. At the same time as the antioxidant, SRAE oil (JOMO process NC140 manufactured by JX Nippon Oil Energy Co., Ltd.) was continuously added to 100 g of the polymer as a softening agent for rubber so as to be 25.0 g, and mixed with a static mixer. ..
The solvent is removed by steam stripping, and a part of the main chain is branched into four branches derived from a branching agent (hereinafter, also referred to as "branching agent structure (1)"), which is a compound represented by the following formula (1). A coupling-conjugated diene-based polymer (Sample 1) having a structure and having a three-branched star-shaped polymer structure derived from a coupling agent was obtained.
The physical characteristics of Sample 1 are shown in Table 1. Regarding the polymer before the addition of the branching agent, the polymer after the addition of the branching agent, and the polymer in each step after the addition of the coupling agent, the molecular weight by GPC measurement and the degree of branching by GPC measurement with a viscometer are By comparison, the structure of the coupling conjugated diene polymer was identified. Hereinafter, the structure of each sample was identified in the same manner.

(In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in a part thereof.
R ^{2 to} R ³ each independently represent 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 a part thereof.
When there are a plurality of them, R ^{1 to} R ³ are independent of each other.
X ¹ represents an independent halogen atom.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3. )

(Coupling Conjugated Diene Polymer (Sample 2))
Examples except that the coupling agent was changed from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table) and the addition amount was changed to 0.0360 mmol / min. Coupling-conjugated diene-based polymer having a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and a 4-branched star-shaped polymer structure derived from the coupling agent in the same manner as in 1. (Sample 2) was obtained. The physical characteristics of Sample 2 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 3))
The coupling agent was changed from tetraethoxysilane to 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (abbreviated as "C" in the table), and the amount added was changed to 0.0360 mmol / min. Except for the above, in the same manner as in Example 1, a coupling has a 4-branched structure derived from the branching agent structure (1) and a 4-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains. A conjugated diene polymer (Sample 3) was obtained. The physical characteristics of Sample 3 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 4))
Change the coupling agent from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table) and add it. Similar to Example 1, a part of the main chain has a 4-branched structure derived from the branching agent structure (1) except that the amount is changed to 0.0360 mmol / min, and the 4-branched structure is derived from the coupling agent. A coupling-conjugated diene polymer having a star-shaped polymer structure (Sample 4) was obtained. The physical characteristics of Sample 4 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 5))
Example 1 except that the coupling agent was changed from tetraethoxysilane to tris (3-trimethoxysilylpropyl) amine (abbreviated as "E" in the table) and the addition amount was changed to 0.0250 mmol / min. Similar to the above, a coupling-conjugated diene polymer having a 4-branched structure derived from the branching agent structure (1) and a 6-branched star-shaped polymer structure derived from the coupling agent in a part of the main chain ( Sample 5) was obtained. The physical characteristics of Sample 5 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 6))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. Except for the above, in the same manner as in Example 1, a coupling has a 4-branched structure derived from the branching agent structure (1) and an 8-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains. A conjugated diamine-based polymer (Sample 6) was obtained. The physical characteristics of Sample 6 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 7))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0160 mmol / min. Except for the above, in the same manner as in Example 1, a coupling has a 4-branched structure derived from the branching agent structure (1) and an 8-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains. A conjugated diamine-based polymer (Sample 7) was obtained. The physical characteristics of Sample 7 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 8))
The addition rate of 1,3-butadiene was changed from 18.6 g / min to 24.3 g / min, the addition rate of styrene was changed from 10.0 g / min to 4.3 g / min, and 2,2-bis (2,2-bis) was added as a polar substance. The addition rate of 2-oxolanyl) propane was changed from 0.081 mmol / min to 0.044 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (in the table). , "F"), and the addition amount was changed to 0.0160 mmol / min. A coupling-conjugated diamine-based polymer (Sample 8) having a branched structure and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of Sample 8 are shown in Table 1.

(Coupling Conjugated Diene Polymer (Sample 9))
The addition rate of 1,3-butadiene was changed from 18.6 g / min to 17.1 g / min, the addition rate of styrene was changed from 10.0 g / min to 11.5 g / min, and 2,2-bis (2,2-bis) was added as a polar substance. The addition rate of 2-oxolanyl) propane was changed from 0.081 mmol / min to 0.089 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (in the table). , "F"), and the addition amount was changed to 0.0160 mmol / min. A coupling-conjugated diene polymer (Sample 9) having a branched structure and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. Table 2 shows the physical characteristics of Sample 9.

(Coupling Conjugated Diene Polymer (Sample 10))
The rate of addition of the polar substance 2,2-bis (2-oxolanyl) propane was changed from 0.081 mmol / min to 0.200 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl)-. Branched to a part of the main chain in the same manner as in Example 1 except that the mixture was changed to 1,3-propanediamine (abbreviated as "F" in the table) and the addition amount was changed to 0.0160 mmol / min. A coupling-conjugated diamine-based polymer (sample 10) having a 4-branched structure derived from the agent structure (1) and an 8-branched star-shaped polymer structure derived from the coupling agent was obtained. The physical characteristics of sample 10 are shown in Table 2.

(Coupling Conjugated Diene Polymer (Sample 11))
Change the branching agent from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), change the addition amount to 0.0350 mmol / min, and cup. Example 1 except that the ring agent was changed from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table) and the addition amount was changed to 0.0360 mmol / min. In the same manner as in the above, a coupling-conjugated diene-based polymer having a bifurcated structure derived from the branching agent structure (1) in a part of the main chains and a tetrabranched star-shaped polymer structure derived from the coupling agent ( Sample 11) was obtained. The physical characteristics of sample 11 are shown in Table 2.

(Coupling Conjugated Diene Polymer (Sample 12))
Change the branching agent from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), change the addition amount to 0.0350 mmol / min, and cup. Change the ring agent from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table)) and add it. Similar to Example 1, a part of the main chain has a bi-branched structure derived from the branching agent structure (1) and a 4-branched structure derived from a coupling agent, except that the amount is changed to 0.0360 mmol / min. A coupling-conjugated diene-based polymer having a star-shaped polymer structure (Sample 12) was obtained. Table 2 shows the physical characteristics of sample 12.

(Coupling Conjugated Diene Polymer (Sample 13))
Change the branching agent from trimethoxy (4-vinylphenyl) silane to dimethylmethoxy (4-vinylphenyl) silane (abbreviated as "BS-2" in the table), change the addition amount to 0.0350 mmol / min, and cup. Except for changing the ring agent from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) and changing the addition amount to 0.0160 mmol / min. Coupling conjugate having a bi-branched structure derived from the branching agent structure (1) and an 8-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains in the same manner as in Example 1. A diamine-based polymer (Sample 13) was obtained. The physical characteristics of sample 13 are shown in Table 2.

(Coupling Conjugated Diene Polymer (Sample 14))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4- (dimethylmethoxysilyl) phenyl) ethylene (abbreviated as "BS-3" in the table), and the amount added was 0. Change to 0120 mmol / min, change the coupling agent from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table), and change the addition amount to 0.0360 mmol / min. Except for the above, in the same manner as in Example 1, a part of the main chain is derived from a branching agent (hereinafter, also referred to as “branching agent structure (2)”) which is a compound represented by the following formula (2). A coupling-conjugated diene-based polymer (Sample 14) having a tri-branched structure and a 4-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 14 are shown in Table 2.

(In the formula (2), R ^{2 to} R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, even if a part thereof has a branched structure. Good. When there are a plurality of them, R ^{2 to} R ⁵ are independent of each other.
X ^{2 to} X ³ represent independent halogen atoms.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3.
a indicates an integer of 0 to 2, b indicates an integer of 0 to 3, and c indicates an integer of 0 to 3. (A + b + c) indicates 3. )

(Coupling Conjugated Diene Polymer (Sample 15))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4- (dimethylmethoxysilyl) phenyl) ethylene (abbreviated as "BS-3" in the table), and the amount added was 0. Change to 0120 mmol / min and change the coupling agent from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table. )), And the addition amount was changed to 0.0360 mmol / min. A coupling-conjugated diene-based polymer (Sample 15) having a 4-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 15 are shown in Table 2.

(Coupling Conjugated Diene Polymer (Sample 16))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4- (dimethylmethoxysilyl) phenyl) ethylene (abbreviated as "BS-3" in the table), and the amount added was 0. Change to 0120 mmol / min, change the coupling agent from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and add 0. An 8-branched star-shaped polymer derived from a coupling agent having a tri-branched structure derived from the branching agent structure (2) in a part of the main chains in the same manner as in Example 1 except that the value was changed to 0160 mmol / min. A coupling-conjugated diamine-based polymer having a structure (Sample 16) was obtained. The physical characteristics of sample 16 are shown in Table 2.

(Coupling Conjugated Diene Polymer (Sample 17))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4-trimethoxysilylphenyl) ethylene (abbreviated as "BS-4" in the table), and the amount added was 0.0210 mmol /. The coupling agent was changed from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table), and the amount added was changed to 0.0360 mmol / min. Coupling conjugate having a 7-branched structure derived from the branching agent structure (2) and a 4-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains in the same manner as in Example 1. A diene-based polymer (Sample 17) was obtained. The physical characteristics of sample 17 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 18))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4-trimethoxysilylphenyl) ethylene (abbreviated as "BS-4" in the table), and the amount added was 0.0210 mmol /. The coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table)). In the same manner as in Example 1, a part of the main chain has a 7-branched structure derived from the branching agent structure (2), except that the addition amount is changed to 0.0360 mmol / min. A coupling-conjugated diene-based polymer (Sample 18) having a 4-branched star-shaped polymer structure derived from the agent was obtained. The physical characteristics of sample 18 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 19))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to 1,1-bis (4-trimethoxysilylphenyl) ethylene (abbreviated as "BS-4" in the table), and the amount added was 0.0210 mmol /. The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was 0.0160 mmol /. Similar to Example 1, a 7-branched structure derived from the branching agent structure (2) is provided in a part of the main chain, and an 8-branched star-shaped polymer structure derived from the coupling agent is formed in the same manner as in Example 1. A coupling-conjugated diamine-based polymer (Sample 19) having the same was obtained. The physical characteristics of sample 19 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 20))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table), and the amount added was changed to 0.0190 mmol / min for coupling. Example 1 except that the agent was changed from tetraethoxysilane to 1,2-bis (triethoxysilyl) ethane (abbreviated as "B" in the table) and the addition amount was changed to 0.0360 mmol / min. Similarly, a coupling-conjugated diene-based polymer (sample) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chains and an 8-branched star-shaped polymer structure derived from the coupling agent. 20) was obtained. The physical characteristics of sample 20 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 21))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table), and the amount added was changed to 0.0190 mmol / min for coupling. The agent was changed from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table)), and the amount added thereof. Has a 4-branched structure derived from the branching agent structure (1) in a part of the main chain, and an 8-branched star derived from the coupling agent, in the same manner as in Example 1 except that A coupling-conjugated diene-based polymer (Sample 21) having a shape polymer structure was obtained. The physical characteristics of sample 21 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 22))
The branching agent was changed from trimethoxy (4-vinylphenyl) silane to trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table), and the amount added was changed to 0.0190 mmol / min for coupling. Except that the agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) and the amount added was changed to 0.0160 mmol / min. , A coupling conjugated diamine having a 4-branched structure derived from the branching agent structure (1) and an 8-branched star-shaped polymer structure derived from the coupling agent in a part of the main chains in the same manner as in Example 1. A system polymer (Sample 22) was obtained. The physical characteristics of sample 22 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 23))
The amount of the branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) was changed from 0.0190 mmol / min to 0.0100 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis. Same as in Example 1 except that (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) was changed and the addition amount was changed to 0.0190 mmol / min. A coupling-conjugated diamine-based polymer (Sample 23) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chains and an 8-branched star-shaped polymer structure derived from the coupling agent. Got The physical characteristics of sample 23 are shown in Table 3.

(Coupling Conjugated Diene Polymer (Sample 24))
The amount of the branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) was changed from 0.0190 mmol / min to 0.0250 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis. Same as in Example 1 except that (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) was changed and the addition amount was changed to 0.0190 mmol / min. Coupling-conjugated diamine-based polymer (Sample 24) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chains and an 8-branched star-shaped polymer structure derived from the coupling agent. Got The physical characteristics of the sample 24 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 25))
The amount of the branching agent trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) was changed from 0.0190 mmol / min to 0.0350 mmol / min, and the coupling agent was changed from tetraethoxysilane to tetrakis. Same as in Example 1 except that (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) was changed and the addition amount was changed to 0.0190 mmol / min. Coupling-conjugated diamine-based polymer (Sample 25) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chains and an 8-branched star-shaped polymer structure derived from the coupling agent. Got The physical characteristics of sample 25 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 26))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. A branching agent structure (1) was added to a part of the main chains in the same manner as in Example 1 except that the SRAE oil added as a softening agent for rubber was changed to liquid rubber (liquid polybutadiene LBR-302 manufactured by Kuraray Co., Ltd.). ) And an 8-branched star polymer structure derived from the coupling agent, a coupling-conjugated diamine polymer (Sample 26) was obtained. The physical characteristics of sample 26 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 27))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. A branching agent structure (1) in a part of the main chain in the same manner as in Example 1 except that it was changed to SRAE oil added as a softening agent for rubber and changed to a resin (terpen resin YS resin PX1250 manufactured by Yasuhara Chemical Co., Ltd.). A coupling-conjugated diamine-based polymer (Sample 27) having a derived 4-branched structure and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 27 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 28))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. Derived from the branching agent structure (1) in a part of the main chain in the same manner as in Example 1 except that it was changed to SRAE oil added as a softening agent for rubber and changed to naphthen oil (naphthen oil Nytex810 manufactured by Nynas). A coupling-conjugated diamine-based polymer (Sample 28) having a 4-branched structure and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 28 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 29))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. Similar to Example 1, a part of the main chain has a 4-branched structure derived from the branching agent structure (1) and an 8-branched star derived from a coupling agent, except that a softening agent for rubber is not added. A coupling-conjugated diamine-based polymer (Sample 29) having a shape polymer structure was obtained. The physical characteristics of sample 29 are shown in Table 4.

(Coupling Conjugated Diene Polymer (Sample 30))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. A branching agent was added to a part of the main chain in the same manner as in Example 1 except that the amount of SRAE oil added as a softening agent for rubber was changed from 25.0 g to 37.5 g with respect to 100 g of the polymer. A coupling-conjugated diamine-based polymer (sample 30) having a 4-branched structure derived from the structure (1) and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. Table 4 shows the physical characteristics of the sample 30.

(Coupling Conjugated Diene Polymer (Sample 31))
An internal volume of 10 L, an internal height (L) to diameter (D) ratio (L / D) of 4.0, an inlet at the bottom and an outlet at the top, and a tank reactor with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
Preliminarily water-removed 1,3-butadiene was mixed at 18.6 g / min, styrene at 10.0 g / min, and n-hexane at 175.2 g / min. In a static mixer provided in the middle of the pipe for supplying this mixed solution to the inlet of the reactive group, n-butyllithium for the residual impurity inactivation treatment was added at 0.103 mmol / min, mixed, and then added to the bottom of the reactive group. Supplied continuously. Further, 2,2-bis (2-oxolanyl) propane as a polar substance is vigorously mixed with a stirrer at a rate of 0.081 mmol / min and n-butyllithium as a polymerization initiator is vigorously mixed at a rate of 0.143 mmol / min1. It was supplied to the bottom of the basic reactor and the temperature inside the reactor was maintained at 67 ° C.
The polymer solution was continuously withdrawn from the top of the first reactor, continuously supplied to the bottom of the second reactor, continued the reaction at 70 ° C., and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stable, a small amount of the polymer solution before the addition of the coupling agent was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed to remove the solvent at 110 ° C. Mooney viscosity and various molecular weights were measured. The physical characteristics are shown in Table 5.
Next, tetraethoxysilane (abbreviated as "A" in the table) was continuously added as a coupling agent to the polymer solution flowing out from the outlet of the reactor at a rate of 0.0480 mmol / min, and statically added. The mixture was mixed using a mixer and the coupling reaction was carried out. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes and the temperature was 68 ° C., until the temperature in the polymerization step and the addition of the coupling agent. The difference from the temperature of was 2 ° C. A small amount of the conjugated diene polymer solution after the coupling reaction was withdrawn, an antioxidant (BHT) was added so as to be 0.2 g per 100 g of the polymer, and then the solvent was removed to remove the bound styrene amount (physical characteristics 6) and The microstructure of the butadiene part (1,2-vinyl bond amount: physical properties 7) was measured. The measurement results are shown in Table 5.
Next, an antioxidant (BHT) was continuously added to the coupling-reacted polymer solution at 0.055 g / min (n-hexane solution) so as to be 0.2 g per 100 g of the polymer, and coupling was performed. The reaction was terminated. At the same time as the antioxidant, as a softening agent for rubber, SRAE oil (JOMO process NC140 manufactured by JX Nippon Oil Energy Co., Ltd.) was continuously added to 100 g of the polymer so as to be 25.0 g, and mixed with a static mixer. bottom. The solvent was removed by steam stripping to obtain a coupling-conjugated diene polymer (Sample 31) having no main chain branching derived from the branching agent and having a three-branched star-shaped polymer structure derived from the coupling agent. .. The physical characteristics of sample 31 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 32))
Change the coupling agent from tetraethoxysilane to 2,2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane (abbreviated as "D" in the table) and add it. Coupling-conjugated diene having a 4-branched star-shaped polymer structure derived from a coupling agent without main chain branching derived from a branching agent, similar to sample 31 except that the amount was changed to 0.0360 mmol / min. A system polymer (Sample 32) was obtained. The physical characteristics of sample 32 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 33))
The coupling agent was changed from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table), and the amount added was changed to 0.0190 mmol / min. A coupling-conjugated diamine-based polymer (Sample 33) having no main chain branching derived from the branching agent and having an 8-branched star-shaped polymer structure derived from the coupling agent was obtained in the same manner as in Sample 31 except for the above. .. The physical characteristics of sample 33 are shown in Table 5.

(Conjugated Diene Polymer (Sample 34))
When the polymerization was sufficiently stable, 0.0190 mmol / min of trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) as a branching agent was added from the bottom of the second reactive group. Similar to sample 31, it has a 4-branched structure derived from the branching agent structure (1) in some of the main chains, except that the coupling agent was added at a rate and no coupling agent was added. A conjugated diene polymer (Sample 34) showing no star-shaped coupling structure was obtained. The physical characteristics of sample 34 are shown in Table 5.
Although the sample 34 did not undergo a coupling reaction, (physical properties 1 to 8) were described in the column of the coupling conjugated diene polymer.

(Coupling Conjugated Diene Polymer (Sample 35))
When the polymerization was sufficiently stable, 0.0190 mmol / min of trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) was added as a branching agent from the bottom of the second reactive group. Add at a rate and in the same manner as in sample 31 except that the amount of tetraethoxysilane (abbreviated as “A” in the table) added as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. , A coupling-conjugated diene-based polymer having a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and a partially 3-branched star-shaped polymer structure derived from the coupling agent (Sample 35). ) Was obtained. The physical characteristics of sample 35 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 36))
When the polymerization was sufficiently stable, 0.0190 mmol / min of trimethoxy (4-vinylphenyl) silane (abbreviated as "BS-1" in the table) as a branching agent was added from the bottom of the second reactive group. Add at a rate, change from tetraethoxysilane to tetrakis (3-trimethoxysilylpropyl) -1,3-propanediamine (abbreviated as "F" in the table) as a coupling agent, and add 0. Similar to sample 31, it has a 4-branched structure derived from the branching agent structure (1) in a part of the main chain except that it is changed to 0038 mmol / min, and a partially 8-branched star-shaped height derived from the coupling agent. A coupling-conjugated diene-based polymer having a molecular structure (Sample 36) was obtained. The physical characteristics of sample 36 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 37))
When the polymerization was sufficiently stable, 0.0350 mmol / min of dimethylmethoxy (4-vinylphenyl)silane (abbreviated as "BS-2" in the table) as a branching agent was added from the bottom of the second reactive group. The branching agent structure was added to some of the main chains in the same manner as in Sample 31, except that the amount of tetraethoxysilane added as the coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. A coupling-conjugated diene polymer (Sample 37) having a bifurcated structure derived from (1) and a partially trifurcated star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 37 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 38))
When the polymerization is sufficiently stable, 1,1-bis (4- (dimethylmethoxysilyl) phenyl) ethylene (abbreviated as "BS-3" in the table) is used as a branching agent from the bottom of the second reactive group. Was added at a rate of 0.0120 mmol / min, and the amount of tetraethoxysilane added as the coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. A coupling-conjugated diene polymer (Sample 38) having a tri-branched structure derived from the branching agent structure (2) in the chain and a partially tri-branched star-shaped polymer structure derived from the coupling agent was obtained. The physical characteristics of sample 38 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 39))
When the polymerization is sufficiently stable, 1,1-bis (4-trimethoxysilylphenyl) ethylene (abbreviated as "BS-4" in the table) is 0 as a branching agent from the bottom of the second reactive group. In the same manner as in sample 31, some main chains were added at a rate of .0210 mmol / min, except that the amount of tetraethoxysilane added as a coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. A coupling-conjugated diene polymer (Sample 39) having a 7-branched structure derived from the branching agent structure (2) and a partially 3-branched star-shaped polymer structure derived from the coupling agent was obtained. The physical characteristics of sample 39 are shown in Table 5.

(Coupling Conjugated Diene Polymer (Sample 40))
When the polymerization was sufficiently stable, trichloro (4-vinylphenyl) silane (abbreviated as "BS-5" in the table) was added as a branching agent from the bottom of the second reactive group at a rate of 0.0190 mmol / min. In the same manner as in Sample 31, a branching agent structure (1) was added to a part of the main chain, except that the amount of tetraethoxysilane added as the coupling agent was changed from 0.0480 mmol / min to 0.0120 mmol / min. A coupling-conjugated diene polymer (Sample 40) having a 4-branched structure derived from) and a partially 3-branched star-shaped polymer structure derived from a coupling agent was obtained. The physical characteristics of sample 40 are shown in Table 5.

[Rubber composition]
(Examples 1 to 30 and Comparative Examples 1 to 10)
Using samples 1 to 40 shown in Tables 1 to 5 as raw rubbers, rubber compositions containing the respective raw rubbers were obtained according to the formulations shown below.

(Rubber component)
-Coupling conjugated diene polymer or conjugated diene polymer (Samples 1-40)
: 80 parts by mass (mass part without softener for rubber)
・ High cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.)
: 20 parts by mass

(Mixing conditions)
The amount of each compounding agent added is indicated by the number of parts by mass with respect to 100 parts by mass of the rubber component containing no softener for rubber.
-Silica (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 75.0 parts by mass ・ Carbon black (trade name "Seast KH (N339)" manufactured by Tokai Carbon Co., Ltd.)
: 5.0 parts by mass ・ Silane coupling agent (trade name “Si75” manufactured by Evonik Degussa, bis (triethoxysilylpropyl) disulfide): 6.0 parts by mass ・ SRAE oil (manufactured by JX Nippon Oil Energy Co., Ltd.) Product name "Process NC140")
: 42.0 parts by mass (including the amount previously added as a softening agent for rubber contained in samples 1 to 40)
-Zinc flower: 2.5 parts by mass-Stearic acid: 1.0 parts by mass-Anti-aging agent (N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine): 2.0 parts by mass -Sulfur: 2.2 parts by mass-Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazil sulfinamide)
1.7 parts by mass ・ Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass ・ Total: 239.4 parts by mass

(Example 31)
A rubber composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
-Silica (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 35.0 parts by mass

(Example 32)
A rubber composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
-Silica (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 100.0 parts by mass

(Example 33)
A rubber polymer composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
・ Silica (Evonik brand name "Ultrasil 9100GR"
Nitrogen adsorption specific surface area 235 m2 / g): 75.0 parts by mass

(Example 34)
A rubber composition was obtained in the same manner as in Example 1 except that the rubber component was changed to the following.
(Rubber component)
-Coupling conjugated diene polymer (Sample 1)
: 20 parts by mass (mass part without softener for rubber)
-Styrene butadiene rubber (trade name "Toughden 3835" manufactured by Asahi Kasei Corporation)
: 60 parts by mass ・ High cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.)
: 20 parts by mass

(Comparative Example 11)
A rubber composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
-Silica (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 25.0 parts by mass

(Comparative Example 12)
A rubber composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
-Silica (trade name "Zeosil Premium 200MP" manufactured by Rhodia)
Nitrogen adsorption specific surface area 220 m2 / g): 160.0 parts by mass

(Comparative Example 13)
A rubber composition was obtained in the same manner as in Example 1 except that the silica was changed to the following composition.
・ Silica (Evonik brand name "Ultrasil 7000GR"
Nitrogen adsorption specific surface area 175 m2 / g): 75.0 parts by mass

(Comparative Example 14)
A rubber composition was obtained in the same manner as in Example 1 except that the rubber component was changed to the following.
(Rubber component)
-Coupling conjugated diene polymer (Sample 1)
: 5 parts by mass (mass part without softener for rubber)
-Styrene butadiene rubber (trade name "Toughden 3835" manufactured by Asahi Kasei Corporation)
: 75 parts by mass ・ High cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.)
: 20 parts by mass

(Comparative Example 15)
A rubber composition was obtained in the same manner as in Example 1 except that the rubber component was changed to the following.
(Rubber component)
-Styrene butadiene rubber (trade name "Toughden 3835" manufactured by Asahi Kasei Corporation)
: 80 parts by mass ・ High cis polybutadiene (trade name "UBEPOL BR150" manufactured by Ube Industries, Ltd.)
: 20 parts by mass

(Kneading method)
The above materials were kneaded by the following method to obtain a rubber composition.
Using a closed kneader (content capacity 0.3L) equipped with a temperature control device, as the first stage kneading, raw rubber (samples 1 to 40) under the conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm. The filler (silica, carbon black), silane coupling agent, SRAE oil, zinc oxide and stearic acid were kneaded. At this time, the temperature of the closed mixer was controlled, and each rubber composition (blending) was obtained at an discharge temperature of 155 to 160 ° C.
Next, as the second stage kneading, the formulation obtained above was cooled to room temperature, an antiaging agent was added, and the mixture was kneaded again in order to improve the dispersion of silica. In this case as well, the discharge temperature of the compound was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer. After cooling, as the third stage kneading, sulfur and vulcanization accelerators 1 and 2 were added and kneaded by an open roll set at 70 ° C. Then, it was molded and vulcanized in a vulcanization press at 160 ° C. for 20 minutes.
The conjugated diene-based polymer composition before vulcanization and the conjugated diene-based polymer composition after vulcanization were evaluated. Specifically, it was evaluated by the following method. The evaluation results are shown in Tables 6 to 11.

(Evaluation 1) Formulation Mooney Viscosity Using the formulation obtained above after the second-stage kneading and before the third-stage kneading as a sample, a Mooney viscometer was used, and the temperature was 130 ° C. in accordance with ISO 289. After preheating for 1 minute, the viscosity after rotating the rotor at 2 rpm for 4 minutes was measured. The result of Comparative Example 1 was indexed as 100. The smaller the index, the better the workability.

(Evaluation 2) Tensile strength and tensile elongation The tensile strength and tensile elongation were measured according to the tensile test method of JIS K6251, and the result of Comparative Example 1 was set as 100 and indexed. The larger the index, the better the tensile strength and tensile elongation (fracture strength).

(Evaluation 3) Abrasion resistance Using an Akron wear tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), the amount of wear at a load of 44.4 N and 1000 rotations was measured in accordance with JIS K6264-2, and the results of Comparative Example 1 were obtained. Was indexed as 100. The larger the index, the better the wear resistance.

(Evaluation 4) Viscoelasticity parameters The viscoelasticity parameters were measured in the torsion mode using a viscoelasticity tester "ARES" manufactured by Leometrics Scientific. Each measured value was indexed with the result for the rubber composition of Comparative Example 1 as 100.
Tan δ measured at 0 ° C. at a frequency of 10 Hz and a strain of 1% was used as an index of wet grip. The larger the index, the better the wet grip.
Further, tan δ measured at a frequency of 10 Hz and a strain of 3% at 50 ° C. was used as an index of fuel efficiency. The smaller the index, the better the fuel efficiency.
Further, the elastic modulus (G') measured at 50 ° C. at a frequency of 10 Hz and a strain of 3% was used as an index of steering stability. The larger the index, the better the steering stability.

As shown in Tables 6 to 11, Examples 1 to 34 had a lower compound Mooney viscosity when prepared as a vulcanized product and showed good processability as compared with Comparative 1 to 15, and were used as a vulcanized product. It was confirmed that it was excellent in abrasion resistance, steering stability and breaking strength at times, and also had an excellent balance between low hysteresis loss property and wet skid resistance.

The rubber composition according to the present invention has industrial applicability in fields such as tire treads, automobile interior and exterior parts, anti-vibration rubbers, belts, footwear, foams, and various industrial supplies.

Claims (9)

With 100 parts by mass of rubber component,
30 to 150 parts by mass of silica with a nitrogen adsorption specific surface area of 180 m ^{2 / g or more,}
Is a rubber composition containing
The rubber component contains 10% by mass or more of the conjugated diene polymer.
The conjugated diene polymer is
The Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less.
The Mooney relaxation rate measured at 100 ° C. is 0.35 or less.
The degree of branching (Bn) by the GPC-light scattering method with a viscosity detector is 8 or more.
Rubber composition. The rubber composition according to claim 1, wherein the modification rate of the conjugated diene polymer measured by the column adsorption GPC method is 60% by mass or more. The conjugated diene polymer has a star-shaped polymer structure with three or more branches and has a star-shaped polymer structure.
At least one branched chain having a star-shaped structure has a portion derived from a vinyl-based monomer containing an alkoxysilyl group or a halosilyl group, and a portion derived from the vinyl-based monomer containing the alkoxysilyl group or the halosilyl group. With a further main chain branching structure,
The rubber composition according to any one of claims 1 or 2. The portion derived from the vinyl-based monomer containing an alkoxysilyl group or a halosilyl group is
A monomer unit based on a compound represented by the following formula (1) or (2).
The rubber composition according to claim 3, which has a branch point of a polymer chain by a monomer unit based on a compound represented by the following formula (1) or (2).

(In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in a part thereof.
R ^{2 to} R ³ each independently represent 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 a part thereof.
When there are a plurality of them, R ^{1 to} R ³ are independent of each other.
X ¹ represents an independent halogen atom.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3. )
(In the formula (2), R ^{2 to} R ⁵ each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, even if a part thereof has a branched structure. Good. When there are a plurality of them, R ^{2 to} R ⁵ are independent of each other.
X ^{2 to} X ³ represent independent halogen atoms.
m represents an integer of 0 to 2, n represents an integer of 0 to 3, and l represents an integer of 0 to 3. (M + n + l) indicates 3.
a indicates an integer of 0 to 2, b indicates an integer of 0 to 3, and c indicates an integer of 0 to 3. (A + b + c) indicates 3. ) The rubber composition according to claim 4, wherein in the formula (1), R ¹ is a hydrogen atom and m = 0, which has a monomer unit based on the compound represented by the formula (1). The rubber composition according to claim 4, which has a monomer unit based on the compound represented by the formula (2), in which m = 0 and b = 0 in the formula (2). In the formula (1), a ^{monomer unit based on the compound represented by the formula (1), in which R 1} is a hydrogen atom, m = 0, l = 0, and n = 3, is used. The rubber composition according to claim 4. In the formula (2), m = 0, l = 0, n = 3, a = 0, b = 0, and c = 3, represented by the formula (2). The rubber composition according to claim 4, which has a monomer unit based on the compound to be used. A tire containing the rubber composition according to any one of claims 1 to 8.