JP7356390B2 - Rubber composition and tire - Google Patents

Description

The present invention relates to a rubber composition and a tire.

BACKGROUND ART There has been an increasing demand for improved fuel efficiency for automobiles, and there has been a demand for improvements in rubber materials used in automobile tires, particularly tire treads that come into contact with the road surface.
In recent years, due to the increasing demand for fuel efficiency regulations for automobiles, there has been a trend toward lighter automobiles by using resin parts, etc., and there has also been an increasing demand for thinner tire members from the viewpoint of weight reduction.

In order to reduce the weight of tires, it is necessary to reduce the thickness of the tread, which is in contact with the road surface and has a high proportion of materials, and in this tread, rubber materials with excellent wear resistance are required more than ever before. There is.
Furthermore, in order to reduce energy loss due to tires during running, rubber materials used for tire treads are required to have low rolling resistance, that is, materials with low hysteresis loss properties.
On the other hand, from the viewpoint of safety, it is required to have excellent handling stability and wet skid resistance, and to have practically sufficient breaking strength.

Examples of rubber materials that meet the above-mentioned demands include rubber compositions containing a rubbery polymer and a reinforcing filler such as carbon black or silica.
When a rubber composition containing silica is used, the balance between low hysteresis loss property and wet skid resistance is improved. In addition, by introducing a functional group that has affinity or reactivity with silica into the molecular end of a highly mobile rubbery polymer, the dispersibility of silica in the rubber composition is improved, and furthermore, Bonding with silica particles reduces the mobility of the molecular ends of the rubber-like polymer, reducing hysteresis loss, improving abrasion resistance, and improving fracture strength.

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

However, when improving the dispersibility of silica in a rubber composition to reduce hysteresis loss, there is a problem in that the rigidity of the rubber composition decreases and the handling stability when used as a tire deteriorates. There is. As a means to increase the rigidity of rubber compositions, Patent Document 5 proposes a technique using fine particle size silica with a large specific surface area as a filler, but fine particle size silica has poor processability and is difficult to form in rubber compositions. The problem is that the dispersibility in the medium tends to be poor, which worsens the low hysteresis loss property.

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

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

As a result of intensive research and study to solve the problems of the prior art described above, the present inventors have found that the Mooney viscosity and Mooney relaxation rate measured at 100°C are within a predetermined range, and the degree of branching (Bn) is within a specific range. It has been discovered that a rubber composition made of a certain conjugated diene copolymer has extremely excellent processability when made into a vulcanizate, and has excellent abrasion resistance, handling stability, and fracture strength when made into a vulcanizate. , we have completed the present invention.
That is, the present invention is as follows.

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

(In formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a portion thereof may have a branched structure.
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 a portion thereof may have a branched structure.
When a plurality of R ¹ to R ³ exist, each of them is independent.
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 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 portion thereof has a branched structure. Good. When a plurality of R ² to R ⁵ exist, they are each independent.
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 represents an integer of 0 to 2, b represents an integer of 0 to 3, and c represents an integer of 0 to 3. (a+b+c) indicates 3. )

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

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

Hereinafter, a mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail.
Note that the following embodiment is an illustration for explaining the present invention, and the present invention is not limited to the following embodiment. The present invention can be implemented with appropriate modifications within the scope of its gist.

[Rubber composition]
The rubber composition of this embodiment is
100 parts by mass of a rubber component,
30 to 150 parts by mass of silica having a nitrogen adsorption specific surface area of 180 m ² /g or more,
Contains.
The rubber component contains 10% by mass or more of a conjugated diene polymer,
The conjugated diene polymer is
Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less,
Mooney relaxation rate measured at 100°C is 0.35 or less,
The degree of branching (Bn) measured by GPC-light scattering method with a viscosity detector is 8 or more.
The rubber composition of the present embodiment has extremely excellent processability when made into a vulcanizate, particularly excellent wear resistance and handling stability when made into a vulcanizate, and has low hysteresis loss properties. It has excellent breaking strength 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 polymer described below.

<Conjugated diene polymer>
The conjugated diene polymer (hereinafter sometimes referred to as the conjugated diene polymer of the present embodiment) contained in the rubber composition of the present embodiment has a Mooney viscosity of 40 to 170 as measured at 100°C. or less, the Mooney relaxation rate measured at 100°C is 0.35 or less, and the degree of branching (hereinafter also referred to as "Bn") as measured by the GPC-light scattering measurement method with a viscosity detector is 8 or more. .
As mentioned above, a rubber composition containing a conjugated diene polymer with specified Mooney viscosity, Mooney relaxation rate, and degree of branching (Bn) measured at 100°C has a high processability when made into a vulcanizate. It has excellent abrasion resistance and handling stability when made into a vulcanized product, and has sufficient breaking strength for practical use.
The conjugated diene polymer contained in the rubber composition of the present embodiment has specified Mooney viscosity, Mooney relaxation rate, and degree of branching (Bn) measured at 100°C, and further has a vinyl bond in the conjugated diene bond unit. By arbitrarily adjusting the amount of aromatic vinyl compound and the amount of aromatic vinyl compound, it has extremely excellent processability when made into a vulcanized product, and has excellent wear resistance and handling stability when made into a vulcanized product, and is sufficient for practical use. The glass transition temperature (hereinafter also referred to as "Tg") of the conjugated diene polymer can be adjusted as desired while maintaining the desired breaking strength.
For example, by setting the amount of vinyl bonds in the conjugated diene bonding unit and the amount of aromatic vinyl compound low, the Tg of the conjugated diene polymer is lowered, resulting in improved wear resistance and fracture strength when made into a vulcanizate. There is a tendency that a rubber composition with improved low hysteresis loss properties can be obtained.
In addition, by setting a high amount of vinyl bonds in the conjugated diene bond unit and a high amount of aromatic vinyl compound, the Tg of the conjugated diene polymer increases, and the processing performance when making it into a vulcanizate improves. Furthermore, there is a tendency to obtain a rubber composition having excellent wet skid resistance.

[Mooney viscosity]
The conjugated diene polymer of this embodiment has a structure with a specified degree of branching (Bn) of 8 or more.
Generally, a polymer having a branched structure tends to have a smaller molecular size when compared to a linear polymer having the same molecular weight. Therefore, the molecular weight of a polymer having a branched structure is calculated by sifting the molecular size of the polymer and measuring it by gel permeation chromatography (hereinafter also referred to as "GPC"), which is a relative comparison method with a standard polystyrene sample. tends to be undervalued.
In addition, the absolute molecular weight measured by the GPC-light scattering measurement method with a viscosity detector is compared with the polystyrene equivalent molecular weight determined by gel permeation chromatography (GPC) measurement, and the molecular size is directly observed by the light scattering method. Since the molecular weight (absolute molecular weight) is measured, it is not affected by the structure of the polymer or interaction with the column packing material, and is not affected by the polymer structure such as the branched structure of conjugated diene polymers. Although it tends to be able to accurately measure Difficult to identify.

On the other hand, the Mooney viscosity is an index indicating the comprehensive characteristics of the conjugated diene polymer, including information on the molecular weight, molecular weight distribution, degree of branching, and softener content of the conjugated diene polymer. Furthermore, the method for measuring Mooney viscosity is specified in ISO 289, and the error in measured values due to machine differences is small, making it extremely effective in controlling the performance of conjugated diene polymers.
In general, viscosity can be considered as an indicator that can replace molecular weight, but since it is difficult to accurately determine the molecular weight of polymers with a branched structure, the present inventors Mooney viscosity was set as one of the requirements for the polymer.
The conjugated diene polymer of this embodiment has a Mooney viscosity (hereinafter also referred to as "ML") measured at 100°C of 40 or more and 170 or less, but normally, in the region near the lower limit, the molecular weight is simply lowered. Even if you adjust the ML by adding a softener (oil, etc.), the Mooney relaxation rate (hereinafter also referred to as "MSR") measured at 100°C will be 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 easier to control the MSR to 0.35 or less.
Note that MSR can be controlled by adjusting the type of branching agent, the amount added thereof, and the type of coupling agent, and the amount added thereof.
That is, in order to obtain a rubber composition that exhibits the desired performance, controlling the molecular weight of the conjugated diene polymer and controlling the Mooney viscosity alone were insufficient, so in this embodiment, the control of the rubber composition In order to increase the elastic modulus, increase the degree of branching of the conjugated diene polymer to 8 or more in addition to the Mooney viscosity (adjust the type and amount of the branching agent and the type and amount of the coupling agent added) By combining these requirements, the elastic modulus (rigidity) of the vulcanizate was increased without impairing the processability of the rubber composition, and the handling stability was improved.

Conjugated diene polymers are characterized by their productivity, processability when made into rubber compositions containing fillers such as silica, and durability when made from vulcanized rubber compositions. From the viewpoint of abrasion resistance, handling stability, and fracture strength, the Mooney relaxation rate and degree of branching (Bn) described below are within a specific range, and the Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less. It is preferably 50 or more and 150 or less, 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 when made into a vulcanized product tend to improve, and when the Mooney viscosity measured at 100°C is 170 or less, This suppresses trouble in the production of a conjugated diene polymer, and improves processability when forming a rubber composition containing a filler such as silica.

As a method for adjusting the Mooney viscosity of the conjugated diene polymer to the above range, 1 part by mass or more and 60 parts by mass or less of a rubber softener, which will be described later, is added to 100 parts by mass of the conjugated diene polymer. There are several methods.
Specifically, when producing a conjugated diene polymer by continuous polymerization, extension with oil or the like is generally performed, but such extension reduces Mooney viscosity and increases Mooney relaxation rate.
From this point of view, the present inventors realized that by specifying the stretched and finished state of the conjugated diene polymer rather than the state of the conjugated diene polymer alone, the processability of the conjugated diene polymer can be appropriately controlled. Focusing on this, we decided to specify the Mooney viscosity of the conjugated diene polymer in a state in which it contains a rubber softener when it is finished by adding a rubber softener.

To measure Mooney viscosity, use a sample made of a conjugated diene polymer pressed into a plate shape, set it in the device, preheat the sample at 100°C for 1 minute, and then rotate the rotor 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 below.

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

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

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

The conjugated diene polymer of this embodiment has a Mooney relaxation rate of 0.35 or less, and in order to make the Mooney relaxation rate of the conjugated diene polymer 0.35 or less, the weight average molecular weight is increased; An effective method is to widen the molecular weight distribution in order to increase the amount of high molecular weight components and to control the molecular structure so as to increase the degree of branching.
For example, in a conjugated diene polymer, if the Mooney viscosity is 40 or more and the degree of branching (Bn) described below is 8 or more, the Mooney relaxation rate tends to be 0.35 or less.
In addition, the Mooney relaxation rate is determined by the amount of polymerization initiator added, the functional number of the branching agent used, the amount of branching agent added, the amount of coupling agent or nitrogen atom-containing modifier used in the manufacturing process of the conjugated diene polymer. It can be controlled by adjusting the number of functional groups and the amount of coupling agent or nitrogen atom-containing modifier added.
For example, after reducing the amount of polymerization initiator added and increasing the molecular weight of the conjugated diene polymer before coupling, adding a branching agent with a large number of functional groups, or using a coupling agent with a large number of functional groups or a nitrogen atom. Coupling with the contained modifier tends to yield a conjugated diene polymer having a Mooney viscosity of 40 or more, a degree of branching (Bn) of 8 or more, and a Mooney relaxation rate of 0.35 or less.

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

Mooney relaxation rate (MSR) can be measured using a Mooney viscometer as follows.
The measurement temperature for the Mooney relaxation rate was 100°C. After preheating the sample for 1 minute at 100°C, the rotor was rotated at 2 rpm, and the Mooney viscosity (ML ₍₁₊₄₎ ), immediately stop the rotation of the rotor, record the torque every 0.1 seconds from 1.6 seconds to 5 seconds after stopping in Mooney units, and plot the torque and time (seconds) logarithmically. The slope of the straight line is determined, and its absolute value is taken as the Mooney relaxation rate (MSR).
More specifically, it can be measured by the method described in Examples below.

In order to make the Mooney relaxation rate 0.35 or less, as mentioned 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 to increase the degree of branching. This is effective.
For example, in a conjugated diene polymer, if the Mooney viscosity is 40 or more and the degree of branching (Bn) is 8 or more, the Mooney relaxation rate tends to be 0.35 or less.
In addition, in order to make the Mooney relaxation rate 0.30 or less, for example, in the conjugated diene polymer, if the Mooney viscosity is 60 or more and the degree of branching (Bn) is 8 or more, the Mooney relaxation rate is 0.30. It tends to be as follows.
Furthermore, the degree of branching (Bn) is determined by, for example, the functional number of the branching agent, the amount of branching agent added, the number of functional groups of the coupling agent or the nitrogen atom-containing modifying agent, the coupling agent or the nitrogen atom-containing modifying agent, It can be controlled by adjusting the amount of the agent added.

[Branching degree (Bn)]
The conjugated diene polymer of this embodiment has a degree of branching (Bn) measured by GPC-light scattering method with a viscosity detector (hereinafter simply referred to as degree of branching (Bn)) from the viewpoint of processability, abrasion resistance, and breaking strength. ) is 8 or more.
The degree of branching (Bn) of 8 or more means that the conjugated diene polymer has 8 or more side polymer chains relative to the substantially longest polymer main chain.
The degree of branching (Bn) of the conjugated diene polymer is calculated using the contraction factor (g') measured by GPC-light scattering measurement method with a viscosity detector, g'=6Bn/[(Bn+1)(Bn+2) ] is defined as
Generally, a branched polymer tends to have a smaller molecular size when compared to a linear polymer having the same absolute molecular weight.
The shrinkage factor (g') is a measure of the size ratio of a molecule to a linear polymer of assumedly the same absolute molecular weight. That is, as the degree of branching of the polymer increases, the shrinkage factor (g') tends to decrease.
For this shrinkage factor, in this embodiment, intrinsic viscosity is used as an index of molecular size, and a linear polymer follows the relational expression of intrinsic viscosity [η]=-3.883M ^0.771 . In the above formula, M is the absolute molecular weight.
However, the shrinkage factor expresses the rate of decrease in molecular size and does not accurately express the branched structure of the polymer.
Therefore, the degree of branching (Bn) of the conjugated diene polymer is calculated using the value of the contraction factor (g') at each absolute molecular weight of the conjugated diene polymer. The calculated "branching degree (Bn)" accurately expresses the number of polymers that are directly or indirectly bonded to each other with respect to the longest main chain structure.
The calculated degree of branching (Bn) serves as an index expressing the branched structure of the conjugated diene polymer. For example, in the case of a typical four-branched star-shaped polymer (four polymer chains connected to the center), two polymer chain arms are connected 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, six polymer chain arms are bonded to the longest highly branched main chain structure, and the degree of branching (Bn) is evaluated as 6.
The conjugated diene polymer contained in the rubber composition of the present embodiment has a degree of branching (Bn) of 8 or more. It means that it is a conjugated diene polymer having the following.
Here, "branch" is formed by directly or indirectly bonding one polymer to another polymer. Moreover, "branching degree (Bn)" is the number of polymers that are 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 has extremely excellent processability when made into a vulcanizate, and has excellent wear resistance and fracture strength when made into a vulcanizate.

In general, as the absolute molecular weight increases, processability tends to deteriorate, and when the absolute molecular weight is increased with a linear polymer structure, the viscosity of the vulcanizate increases significantly, resulting in a significant decrease in processability. Getting worse.
Therefore, even if a large number of functional groups are introduced into the conjugated diene polymer to improve its affinity and/or reactivity with the silica blended as a filler, silica cannot be sufficiently absorbed into the conjugated diene polymer during the kneading process. It becomes impossible to disperse in the polymer. As a result, the function of the introduced functional group is not exhibited, and the originally expected effects of improving low hysteresis loss property and wet skid resistance due to the introduction of the functional group tend not to be exhibited.
On the other hand, in the rubber composition of the present embodiment, by specifying the conjugated diene polymer to have a degree of branching (Bn) of 8 or more, the viscosity increases when it is made into a vulcanizate due to an increase in the absolute molecular weight. is significantly suppressed, and, for example, it is sufficiently mixed with silica etc. in the kneading process, making it possible to disperse silica around the conjugated diene polymer. As a result, for example, in conjugated diene polymers, it is possible to improve abrasion resistance and fracture strength by setting a large molecular weight, and by dispersing silica around the polymer by sufficient kneading, functional groups can be It becomes possible to act and/or react, and a rubber composition 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 the Examples below.

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 still more preferably 15 or more. .
Conjugated diene polymers having a degree of branching (Bn) within this range tend to have excellent processability when made into a vulcanizate.
Further, the upper limit of the degree of branching (Bn) of the conjugated diene polymer is not particularly limited, and may be higher than the detection limit, but is preferably 84 or less, more preferably 80 or less, and even more 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 made into a vulcanized product.

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

[Coupled conjugated diene polymer]
In the manufacturing process of the conjugated diene polymer of this embodiment, a trifunctional or higher functional reactive compound (hereinafter referred to as a "coupling agent") is added to the active end of the conjugated diene polymer obtained through the polymerization and branching process. ) is preferably used to conduct the coupling reaction.
In the coupling reaction step, one end of the active end of the conjugated diene polymer is subjected to a coupling reaction 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 below.

[Coupling agent]
In this 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 below.

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

[Modifier with nitrogen atom-containing group]
The conjugated diene polymer of this embodiment is a trifunctional or more reactive compound having a nitrogen atom-containing group, which reacts with the active terminal of the conjugated diene polymer obtained through the polymerization and branching process. A conjugated diene polymer obtained by carrying out a coupling reaction using a chemical compound (hereinafter also referred to as a "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 modifying agent having a nitrogen atom-containing group to obtain a conjugated diene polymer.
Conjugated diene polymers coupled using a modifying agent having a nitrogen atom-containing group have good dispersibility of silica and good processability when made into a rubber composition containing fillers such as silica. Furthermore, when made into a vulcanized product, the abrasion resistance and fracture strength are good, and the balance between low hysteresis loss 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 below.

Examples of the modifier having a nitrogen atom-containing group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen group-containing carbonyl compounds, nitrogen group-containing vinyl compounds, nitrogen group-containing Examples include epoxy compounds.
The nitrogen atom-containing functional group of the modifying agent having a nitrogen atom-containing group is preferably an amine compound that does not have active hydrogen, such as a tertiary amine compound, or a protected amine in which the above-mentioned active hydrogen is substituted with a protecting group. compounds, imine compounds represented by the general formula -N=C, and alkoxysilane compounds bonded to the nitrogen atom-containing group. More specifically, it will be described in the method for producing a conjugated diene polymer described below.

[Modification rate of conjugated diene polymer]
The conjugated diene polymer of this embodiment has a modification rate of 60% by mass or more as measured by column adsorption GPC method.
In this 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 to the total amount of the conjugated diene polymer modified by the nitrogen atom-containing modifier is expressed as a percentage.
On the other hand, even when a polymer is branched using a branching agent containing a nitrogen atom, the resulting conjugated diene polymer will have a nitrogen atom-containing functional group, so this branched polymer will also have a lower modification rate. It will be counted during calculation.
That is, in this specification, the total mass ratio of the polymer subjected to a coupling reaction with a modifier having a nitrogen atom-containing functional group and/or the polymer branched with a branching agent having a nitrogen atom-containing functional group is , is the "denaturation rate".

The conjugated diene polymer of this embodiment has at least one end modified with a nitrogen atom-containing group, which improves processability when forming a rubber composition containing a filler, etc., and improves vulcanization of the rubber composition. There is a tendency for the balance between low hysteresis loss and wet skid resistance to improve dramatically while maintaining wear resistance and breaking strength when used as a product.

The conjugated diene polymer of this embodiment is selected from the column column with respect to the total amount of the conjugated diene polymer from the viewpoint of processability, abrasion resistance, fracture strength, and the balance between low hysteresis loss property and wet skid resistance. It is preferable that the modification rate (hereinafter also simply referred to as "modification rate") measured by adsorption GPC method is 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, which can separate functional group-containing modified components and non-modified components.
This chromatography method uses a gel permeation chromatography column packed with a polar substance such as silica that adsorbs specific functional groups, and quantifies the non-adsorbed components using an internal standard for comparison. method (column adsorption GPC method).
More specifically, the denaturation rate is calculated from the difference between the chromatogram of a sample solution containing a sample and a low molecular weight internal standard polystyrene on a polystyrene gel column and the chromatogram measured on a silica column. Obtained by measuring the amount.
More specifically, the modification rate can be measured by the method described in the Examples.

The modification rate of the conjugated diene polymer can be controlled by adjusting the amount of modifier added and the reaction method, and can thereby be controlled to 60% by mass or more.
For example, a method of polymerizing using an organolithium compound having at least one nitrogen atom in the molecule as described below 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 achieved by combining a method using a modifier having the structural formula and controlling the polymerization conditions.

[Branched structure of conjugated diene polymer]
From the viewpoint of balance between processability and wear resistance, the conjugated diene polymer of this embodiment is a conjugated diene polymer having a star-shaped polymer structure with three or more branches, and at least one star-shaped structure. has a part derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group in the branch chain of A conjugated diene polymer having a branched structure is preferred.

The term "star-shaped polymer structure" as used herein refers to a structure in which multiple polymer chains (arms) are connected from one central branch point.
Moreover, one central branch point here has a substituent containing an atom derived from a coupling agent or a nitrogen atom derived from a modifier.
The "main chain branched structure" as used herein means that a polymer chain forms a branch point at a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group, and further extends from the branch point to a polymer chain. A structure in which the (arm) is extended.

From the viewpoint of improving the degree of branching (Bn) of the conjugated diene polymer, in the conjugated diene polymer, the main chain branching point constituted by a moiety derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group is , 2 or more branching points, preferably 3 or more branching points, more preferably 4 or more branching points, and the branched structure derived from the star-shaped polymer structure formed by the coupling agent in the reaction step, The number of branches is preferably 3 or more, more preferably 4 or more, even more preferably 6 or more, and even more preferably 8 or more.
Note that the degree of branching (Bn) increases both when modifying with a coupling agent that forms a star-shaped structure and when introducing a branching agent into the polymer, but when the entire polymer chain is branched by a coupling agent, The contribution to the degree of branching (Bn) is greater when
In designing a polymer, the degree of branching (Bn) can be controlled by selecting the coupling agent and selecting the type and amount of the branching agent. ) can be easily controlled.

[Main chain branched structure]
The main chain branched structure has two or more branching points, preferably three or more branching points, and four or more branching points at branching points in a portion derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group. It is more preferable.
Further, the branch point forming the main chain branched structure preferably has at least two or more polymer chains, more preferably has three or more polymer chains that are not main chains, and even more preferably has three or more polymer chains that are not main chains. has four or more polymer chains that are not main chains.
In particular, for main chain branched structures consisting of moieties derived from vinyl monomers containing alkoxysilyl groups or halosilyl groups, signal detection using ²⁹ Si-NMR shows a range of -45 ppm to -65 ppm, 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 this 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, the number of branches is 6 or more, and even more preferably 8 or more branches.
A conjugated diene polymer having a star-shaped polymer structure with three or more branches, in which at least one branch chain of the star-shaped structure has a moiety derived from a vinyl monomer containing an alkoxysilyl group or a halosilyl group. However, regarding the method for producing a conjugated diene polymer having an additional main chain branched structure in the moiety derived from the vinyl monomer containing the alkoxysilyl group or halosilyl group, first, 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 branched structure" can be formed by adjusting the number of functional groups of the branching agent, the amount of the branching agent added, and the amount of the branching agent added. can be controlled by adjusting the timing.
The specific manufacturing method involves polymerizing using an organolithium compound as a polymerization initiator, adding a branching agent that provides a specific branching point during or after the polymerization, and continuing the polymerization to achieve a specific branching rate. Examples include a method of denaturing using a denaturing agent that gives .
Means for controlling such polymerization conditions will be described in the production method in Examples described later.

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

(In formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a portion thereof may have a branched structure.
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 a portion thereof may have a branched structure.
When a plurality of R ¹ to R ³ exist, each of them is independent.
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 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 a plurality of R ² to R ⁵ are present, each of them is independent.
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 represents an integer of 0 to 2, b represents an integer of 0 to 3, and c represents an integer of 0 to 3. (a+b+c) indicates 3. )

The conjugated diene polymer of the present embodiment has a monomer unit based on a compound represented by the above formula (1), in which R ¹ is a hydrogen atom and m=0. It is preferable that the conjugated diene polymer has the following properties. This increases the number of branches, resulting in improved wear resistance and workability.

Further, the conjugated diene polymer of the present embodiment has a monomer unit based on a compound represented by the formula (2), where m=0 and b=0. , a conjugated diene polymer is preferred. This provides the effect of improving wear resistance and workability.

Further, in the conjugated diene polymer of the present embodiment, in the formula (2), m = 0, l = 0, n = 3, a = 0, b = 0, and c = 3, A modified conjugated diene polymer having a monomer unit based on the compound represented by the above formula (2) is preferable. This provides the effect of improving wear resistance and workability.

Further, the conjugated diene polymer of the present embodiment has the above formula (1), in which R ¹ is a hydrogen atom, m=0, l=0, and n=3. ) A conjugated diene polymer having a monomer unit based on a compound represented by the following is more preferable. This improves the modification rate and the degree of branching, resulting in improved fuel efficiency, wear resistance, and workability.

<Branching agent>
In the conjugated diene polymer of this embodiment, when constructing the main chain branched 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 monomer containing the alkoxysilyl group or halosilyl group is a monomer unit based on a compound represented by the following formula (1) or (2), and the conjugated diene type of this embodiment It is preferable that the polymer has a structure having a branching point of a polymer chain formed by a monomer unit based on a compound represented by the following formula (1) or (2).

(In formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a portion thereof may have a branched structure.
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 a portion thereof may have a branched structure.
When a plurality of R ¹ to R ³ exist, each of them is independent.
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 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 a plurality of R ² to R ⁵ are present, each of them is independent.
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 represents an integer of 0 to 2, b represents an integer of 0 to 3, and c represents an integer of 0 to 3. (a+b+c) indicates 3. )

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

Furthermore, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is m=0 in formula (2) from the viewpoint of improving the degree of branching. A compound in which b=0 is preferable.

In addition, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is selected from the formula A compound in which R ¹ in (1) is a hydrogen atom, m=0, l=0, and n=3 is more preferable.

In addition, in this embodiment, the branching agent used when constructing the main chain branched structure of the conjugated diene polymer is =0, l=0, n=3, and compounds in which a=0, b=0, c=3 are preferred.

The branching agent represented by the formula (1) is not limited to the following, but examples include 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)silane, -vinylphenyl)silane, dimethylpropoxy(2-vinylphenyl)silane, dimethylbutoxy(2-vinylphenyl)silane, dimethylisopropoxy(2-vinylphenyl)silane, trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-vinylphenyl)silane -isopropenylphenyl) silane, tripropoxy (4-isopropenylphenyl) silane, tributoxy (4-isopropenylphenyl) silane, triisopropoxy (4-isopropenylphenyl) silane, trimethoxy (3-isopropenylphenyl) silane, Triethoxy(3-isopropenylphenyl)silane, tripropoxy(3-isopropenylphenyl)silane, tributoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl) ) silane, triethoxy(2-isopropenylphenyl)silane, tripropoxy(2-isopropenylphenyl)silane, tributoxy(2-isopropenylphenyl)silane, triisopropoxy(2-isopropenylphenyl)silane, dimethoxymethyl(4 -isopropenylphenyl)silane, diethoxymethyl(4-isopropenylphenyl)silane, dipropoxymethyl(4-isopropenylphenyl)silane, dibutoxymethyl(4-isopropenylphenyl)silane, diisopropoxymethyl(4- isopropenylphenyl)silane, dimethoxymethyl(3-isopropenylphenyl)silane, diethoxymethyl(3-isopropenylphenyl)silane, dipropoxymethyl(3-isopropenylphenyl)silane, dibutoxymethyl(3-isopropenylphenyl) ) silane, diisopropoxymethyl (3-isopropenylphenyl) silane, dimethoxymethyl (2-isopropenylphenyl) silane, diethoxymethyl (2-isopropenylphenyl) silane, dipropoxymethyl (2-isopropenylphenyl) silane , dibutoxymethyl(2-isopropenylphenyl)silane, diisopropoxymethyl(2-isopropenylphenyl)silane, dimethylmethoxy(4-isopropenylphenyl)silane, dimethylethoxy(4-isopropenylphenyl)silane, dimethylpropoxy (4-isopropenylphenyl)silane, dimethylbutoxy(4-isopropenylphenyl)silane, dimethylisopropoxy(4-isopropenylphenyl)silane, dimethylmethoxy(3-isopropenylphenyl)silane, dimethylethoxy(3-isopropenylphenyl)silane, nylphenyl)silane, dimethylpropoxy(3-isopropenylphenyl)silane, dimethylbutoxy(3-isopropenylphenyl)silane, dimethylisopropoxy(3-isopropenylphenyl)silane, dimethylmethoxy(2-isopropenylphenyl)silane, dimethyl Ethoxy(2-isopropenylphenyl)silane, dimethylpropoxy(2-isopropenylphenyl)silane, dimethylbutoxy(2-isopropenylphenyl)silane, dimethylisopropoxy(2-isopropenylphenyl)silane, trichloro(4-vinylphenyl) ) silane, trichloro(3-vinylphenyl)silane, trichloro(2-vinylphenyl)silane, tribromo(4-vinylphenyl)silane, tribromo(3-vinylphenyl)silane, tribromo(2-vinylphenyl)silane, dichloromethyl (4-vinylphenyl)silane, dichloromethyl(3-vinylphenyl)silane, dichloromethyl(2-vinylphenyl)silane, dibromomethyl(4-vinylphenyl)silane, dibromomethyl(3-vinylphenyl)silane, dibromomethyl (2-vinylphenyl)silane, dimethylchloro(4-vinylphenyl)silane, dimethylchloro(3-vinylphenyl)silane, dimethylchloro(2-vinylphenyl)silane, dimethylbromo(4-vinylphenyl)silane, dimethylbromo Examples include (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, and 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 formula (2) is not limited to the following, but includes, for example, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxy silylphenyl)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 is 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 are preferred, 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 in which the above-mentioned Mooney viscosity, Mooney relaxation rate, and degree of branching (Bn) are set within specific ranges. a polymerization and branching step for obtaining a conjugated diene polymer having a main chain branched structure by adding a branching agent while polymerizing at least a conjugated diene compound using as a polymerization initiator; and a coupling step of coupling the two with a coupling agent.

A method for producing a conjugated diene polymer includes polymerizing at least a conjugated diene compound using an organolithium compound as a polymerization initiator in the presence of an organolithium compound, and at least one of the various branching agents described above. a polymerization and branching step to obtain a conjugated diene polymer having a main chain branched structure using It is preferable to have the following.

The conjugated diene polymer may be a homopolymer of a single conjugated diene compound, a polymer or copolymer of different types of conjugated diene compounds, or a copolymer of a conjugated diene compound and an aromatic vinyl compound. Good too.

Conjugated diene compounds include, but are not particularly limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1 , 3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of industrial availability.
These may be used alone or in combination of two or more.

Furthermore, examples of the aromatic vinyl compound include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferred from the viewpoint of industrial availability.
These may be used alone or in combination of two or more.

As for the so-called microstructure (ratio of aromatic vinyl compound amount and vinyl bond amount) of the copolymer of a conjugated diene compound and an aromatic vinyl compound, the aromatic vinyl compound amount is preferably 0 to 45% by mass, more preferably The vinyl bond amount is preferably 23 to 70 mol%, more preferably 27 to 65 mol%. In a conjugated diene polymer, Mooney viscosity, Mooney relaxation rate, and degree of branching are determined by the amount of polymerization initiator added, the type (functionality) and amount of branching agent, and the type (functionality) and amount of coupling agent. , is controlled by the amount (type) of rubber softener added, and is little influenced by the microstructure. Therefore, it is possible to appropriately design the microstructure within the range of general microstructures. However, as described above, the amount of aromatic vinyl compounds and the amount of vinyl bonds affect the Tg of the conjugated diene polymer, so it is preferable to set them within the above ranges from the viewpoint of fuel efficiency and braking performance.

[Polymerization and branching process]
The polymerization and branching steps in the method for producing a conjugated diene polymer include, for example, using an organic monolithium compound as a polymerization initiator, polymerizing at least a conjugated diene compound, and adding a branching agent to form a main chain branched structure. This is a process for obtaining a conjugated diene polymer.

In the polymerization step, it is preferable to perform polymerization by a growth reaction based on a living anion polymerization reaction, whereby a conjugated diene polymer having an active terminal can be obtained. Thereafter, branching of the main chain can be appropriately controlled in a branching step using a branching agent, and a conjugated diene polymer with a high modification rate can be obtained.

[Polymerization initiator]
As the polymerization initiator, at least an organic monolithium compound can be used.
Examples of the organic monolithium compound include, but are not limited to, low molecular weight compounds and solubilized oligomeric organic monolithium compounds.
In addition, examples of organic monolithium compounds include compounds having a carbon-lithium bond, compounds having a nitrogen-lithium bond, and compounds having a tin-lithium bond in terms of the bonding mode between the organic group and the lithium.

The amount of the organic monolithium compound used as a polymerization initiator is preferably determined depending on the molecular weight of the desired conjugated diene polymer.
The amount of monomer such as a conjugated diene compound used relative to the amount of polymerization initiator used is related to the degree of polymerization of the desired conjugated diene polymer. That is, it tends to be related to number average molecular weight and/or weight average molecular weight.
Therefore, in order to increase the molecular weight of the conjugated diene polymer, the amount of polymerization initiator used should be adjusted to decrease, and in order to decrease the molecular weight, it is better to adjust the amount of polymerization initiator to be increased. good.

The organic monolithium compound is preferably an alkyllithium compound having a substituted amino group or dialkylaminolithium from the viewpoint of being used as one method for introducing a nitrogen atom into a conjugated diene polymer.
In this case, a conjugated diene polymer having a nitrogen atom consisting of an amino group at the polymerization initiation terminal is obtained.

A substituted amino group is an amino group that does not have an active hydrogen or has a structure in which the active hydrogen is protected.
Examples of alkyllithium compounds having an amino group without active hydrogen include, but are not limited to, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-dimethylaminopropyllithium, and 4-(methylpropylamino)butyllithium. - Hexamethyleneiminobutyllithium.
Examples of the alkyllithium compound having an amino group with a protected active hydrogen structure include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.

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

These organic monolithium compounds having substituted amino groups are made by reacting a small amount of a polymerizable monomer, such as 1,3-butadiene, isoprene, or styrene, to make them solubilized in n-hexane or cyclohexane. It can also be used as an oligomeric organomonolithium compound.

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

These organic monolithium compounds may be used alone or in combination of two or more. It may also be used in combination with other organometallic compounds.
Examples of the other organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds.
Examples of alkaline earth metal compounds include, but are not limited to, organic magnesium compounds, organic calcium compounds, and organic strontium compounds. Also included are alkaline earth metal alkoxide, sulfonate, carbonate, and amide compounds.
Examples of organomagnesium compounds include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

In the polymerization step, the polymerization reaction mode is not limited to the following, but includes, for example, a batch type (also referred to as "batch type") and a continuous type polymerization reaction mode.
In continuous mode, one or more connected reactors can be used. As the continuous reactor, for example, a tank type or a tube type with a stirrer is used. In the continuous system, preferably, monomers, inert solvents, and polymerization initiators are continuously fed into a reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymerization is continuously carried out. The coalescent solution is drained.
As the batch reactor, for example, a tank-type reactor equipped with a stirrer is used. In the batch system, preferably the monomer, inert solvent, and polymerization initiator are fed, and if necessary, the monomer is added continuously or intermittently during the polymerization to form the polymer in the reactor. A polymer solution containing the polymer is obtained, and the polymer solution is discharged after the polymerization is completed.
In the method for producing a conjugated diene polymer of this embodiment, in order to obtain a conjugated diene polymer having a high proportion of active terminals, it is necessary to continuously discharge the polymer and use it for the next reaction in a short time. A continuous system is preferred.

The conjugated diene polymer is preferably polymerized in an inert solvent.
Examples of the inert solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic solvents such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; Hydrocarbons include aromatic hydrocarbons such as benzene, toluene, and xylene, and hydrocarbons consisting of mixtures thereof.
By treating allenes and acetylenes, which are impurities, with an organometallic compound before subjecting them to the polymerization reaction, a conjugated diene polymer with a high concentration of active terminals tends to be obtained, resulting in a high modification rate. This is preferred because a conjugated diene polymer tends to be obtained.

In the polymerization step, a polar compound may be added. This allows the aromatic vinyl compound to be randomly copolymerized with the conjugated diene compound, and the polar compound tends to also be used as a vinylating agent to control the microstructure of the conjugated diene moiety. It also tends to be effective in promoting polymerization reactions.

Examples of polar compounds include, but are not limited to, 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, Alkali metal alkoxide compounds such as sodium amylate; phosphine compounds such as triphenylphosphine, etc. can be used.
These polar compounds may be used alone or in combination of two or more.

The amount of the polar compound to be used is not particularly limited and can be selected depending on the purpose, etc., 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 (vinylating agent) can be used in an appropriate amount as a regulator of the microstructure of the conjugated diene moiety of the conjugated diene polymer, depending on the desired amount of vinyl bonds.
Many polar compounds have an effective randomizing effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds, and tend to be used as agents to adjust the distribution of aromatic vinyl compounds and adjust the amount of styrene blocks. It is in.
As a method of 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 combined. A method may be used in which the polymerization reaction is started and the remaining 1,3-butadiene is added intermittently during the copolymerization reaction.

The polymerization temperature in the polymerization step is preferably a temperature at which living anion polymerization proceeds, and from the viewpoint of productivity, it is more preferably 0°C or higher, and even more preferably 120°C or lower. By falling within this range, it tends to be possible to ensure a sufficient amount of the modifier to react with the active end after completion of polymerization. Even more preferably, the temperature is 50°C or more and 100°C or less.

In the method for producing a conjugated diene polymer of the present embodiment, the amount of branching agent added in the branching step of forming a main chain branched structure is not particularly limited, and can be selected depending on the purpose, etc. 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 less, per 1 mol of polymerization initiator. More preferably, it is less than mol.
The branching agent can be used in an appropriate amount depending on the desired number of branching points in the main chain branching structure of the conjugated diene moiety of the target conjugated diene polymer.

In the branching step, the timing of adding the branching agent is not particularly limited and can be selected depending on the purpose, etc., but from the viewpoint of improving the absolute molecular weight and modification rate of the conjugated diene polymer, After adding the polymerization initiator, the timing is preferable when the raw material conversion rate is 20% or more, more preferably 40% or more, even more preferably 50% or more, even more preferably 65% or more, It is even more preferable that 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-mentioned contents may be repeated.
The monomer to be added is not particularly limited, but from the viewpoint of improving the modification rate of the conjugated diene polymer, it is preferably 5% or more of the total amount of conjugated diene monomers used in the polymerization step, for example, the total amount of butadiene. It is more preferably 10% or more, even more preferably 15% or more, even more preferably 20% or more, even more preferably 25% or more, and especially 30% or less. preferable.

When the amount of monomer to be added is within the above range, the molecular weight between the branching point caused by the branching agent and the branching point caused by the coupling agent becomes long, and a highly linear molecular structure tends to be obtained. By creating a highly linear molecular structure, the entanglement of the molecular chains of the conjugated diene polymer increases when it is made into a vulcanizate, resulting in a rubber composition with excellent wear resistance, handling stability, and fracture strength. tend to be obtained.

The conjugated diene polymer of this 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 other monomers. good.
For example, if the conjugated diene monomer is butadiene or isoprene, and this is polymerized with a branching agent containing a vinyl aromatic moiety, the polymer chain will be so-called polybutadiene or polyisoprene, and the branched moiety will contain a vinyl aromatic-derived structure. Becomes a polymer. By having such a structure, it is possible to improve the linearity of each polymer chain and the crosslinking density after vulcanization, thereby improving wear resistance. Therefore, the conjugated diene polymer of the present embodiment is suitable for applications such as tires, resin modification, automobile interior and exterior products, anti-vibration rubber, and footwear.
When using a conjugated diene polymer for tire tread applications, a copolymer of a conjugated diene monomer, an aromatic vinyl monomer, and a branching agent is suitable, and the amount of bonded conjugated diene in the copolymer for this use is 40% by mass. % or more and 100% by mass or less, more preferably 55% by mass or more and 80% by mass or less.
Further, the amount of bonded 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 preferably 20% by mass or more and 45% by mass or less. is more preferable. When the amount of bonded conjugated diene and the amount of bonded aromatic vinyl are in the above ranges, the balance between low hysteresis loss property and wet skid resistance, abrasion resistance, and fracture strength are more excellent when made into a vulcanized product. There is a tendency.
Here, the amount of bonded aromatic vinyl can be measured by ultraviolet absorption of the phenyl group, and from this, the amount of bonded conjugated diene can also be determined. Specifically, it is measured according to the method described in the Examples described later.

In the conjugated diene polymer of this embodiment, the amount of vinyl bonds in the conjugated diene bond units is not particularly limited, but is preferably 10 mol% or more and 75 mol% or less, and 20 mol% or more and 65 mol% or less. It is more preferable that
When the amount of vinyl bonds is within the above range, the balance between low hysteresis loss and wet skid resistance, abrasion resistance, and fracture strength tend to be better when formed into a vulcanized product.
Here, when the conjugated diene polymer is a copolymer of butadiene and styrene, the butadiene bonding units are separated by Hampton's method (R.R. Hampton, Analytical Chemistry, 21, 923 (1949)). The vinyl bond amount (1,2-bond amount) can be determined. Specifically, it is measured by the method described in Examples below.

Regarding the microstructure of the conjugated diene polymer of this embodiment, the amount of each bond in the conjugated diene polymer is within the above range, and the glass transition temperature of the conjugated diene polymer is -70°C or higher -15°C. When the temperature is in the range below .degree. C., it tends to be possible to obtain a more excellent vulcanizate due to the balance between low hysteresis loss property and wet skid resistance.
Regarding the glass transition temperature, according to ISO 22768:2006, a DSC curve is recorded while increasing the temperature in a predetermined temperature range, and the peak top (inflection point) of the DSC differential curve is taken as the glass transition temperature.

When the conjugated diene polymer of this 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 chained is small or absent. . More specifically, when the conjugated diene polymer is a butadiene-styrene copolymer, the method of Kolthoff (I.M. KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)) is used. In a known method of decomposing a copolymer and analyzing the amount of polystyrene insoluble in methanol, the number of blocks in which 30 or more aromatic vinyl units are chained is preferably 5, based on the total amount of the copolymer. 0% by mass or less, more preferably 3.0% by mass or less.

When the conjugated diene polymer of the present embodiment is a conjugated diene-aromatic vinyl copolymer, it is preferable that the proportion of aromatic vinyl units present alone is large from the viewpoint of improving fuel efficiency.
Specifically, when the conjugated diene-based polymer is a butadiene-styrene copolymer, the conjugated diene-based polymer is removed by an ozonolysis method known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)). When the coalescence is decomposed and the styrene chain distribution is analyzed by GPC, the amount of isolated styrene is 40% by mass or more based on the total amount of combined styrene, and the chain styrene structure with 8 or more styrene chains is 5.0% by mass. % or less.
In this case, the resulting vulcanized rubber exhibits excellent performance with particularly low hysteresis loss.

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

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 modifying agent 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 more reactive compound, but preferably has a silicon atom. It is a trifunctional or more reactive compound.
Examples of the trifunctional or higher functional reactive compound having a silicon atom include, but are not limited to, halogenated silane compounds, epoxidized silane compounds, vinylated silane compounds, alkoxysilane compounds, and nitrogen-containing groups. Examples include alkoxysilane compounds.

Examples of the halogenated silane compound as a coupling agent include, but are not limited to, methyltrichlorosilane, tetrachlorosilane, tris(trimethylsiloxy)chlorosilane, tris(dimethylamino)chlorosilane, hexachlorodisilane, bis( trichlorosilyl)methane, 1,2-bis(trichlorosilyl)ethane, 1,2-bis(methyldichlorosilyl)ethane, 1,4-bis(trichlorosilyl)butane, 1,4bis(methyldichlorosilyl)butane, etc. can be mentioned.

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

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

[Modifier with nitrogen atom-containing group]
Modifiers having a nitrogen atom content include, but are not limited to, for example, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds having a nitrogen atom-containing group, and vinyl compounds having a nitrogen atom-containing group. compounds, epoxy compounds having a nitrogen atom-containing group, and the like.

In the modifier having a nitrogen atom-containing group, the nitrogen atom-containing functional group is preferably an amine compound having no active hydrogen, such as a tertiary amine compound, a protected compound in which the above-mentioned active hydrogen is substituted with a protecting group, etc. amine compounds represented by the general formula -N═C, and alkoxysilane compounds bonded to the nitrogen atom-containing group.

Examples of isocyanate compounds that are modifiers having a nitrogen atom-containing group include, but are not limited to, 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-benzene triisocyanate, and the like.

Examples of isocyanuric acid derivatives that are modifying agents having a nitrogen atom-containing group include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3, 5-Tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinane-2,4,6-trione, 1,3,5 -Tris(isocyanatomethyl)-1,3,5-triazinane-2,4,6-trione, 1,3,5-trivinyl-1,3,5-triazinane-2,4,6-trione, etc. It will be done.

Examples of the carbonyl compound which is a modifying agent having a nitrogen atom-containing group include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazo Lydinone, 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-pyridylketone, methyl-4-pyridylketone, propyl-2-pyridylketone, di-4-pyridylketone, 2-benzoyl Pyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, N,N-methyl diethylcarbamate, N,N-diethylacetamide, N,N -dimethyl-N',N'-dimethylaminoacetamide, N,N-dimethylpicolinic acid amide, N,N-dimethylisonicotinic acid amide, and the like.

Examples of the vinyl compound that is a modifying agent having a nitrogen atom-containing group include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, 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.

Examples of the epoxy compound which is a modifying agent having a nitrogen atom-containing group include, but are not limited to, hydrocarbon compounds containing an epoxy group bonded to an amino group, and further epoxy groups bonded to an ether group. It may have. Examples of such epoxy compounds include, but are not limited to, the epoxy compounds represented by general formula (i).

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

The divalent or higher-valent hydrocarbon group is a saturated or unsaturated hydrocarbon group that may be linear, branched, or cyclic, 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 be a cyclic structure bonded to each other.
Further, when R ³ is a hydrocarbon group, it may be a cyclic structure bonded to R and each other. In the case of the above-mentioned cyclic structure, N bonded to R ³ and R may be directly bonded.
In the formula (i) above, n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

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

The epoxy compound which is a modifying agent having a nitrogen atom-containing group is preferably one having an epoxy group-containing hydrocarbon group, particularly an epoxy group-containing hydrocarbon group bonded to an amino group or an ether group, and more preferably a glycidyl group-containing hydrocarbon group. It has a hydrogen group.
The epoxy group-containing hydrocarbon group bonded to the amino group or ether group is not particularly limited, and examples thereof include a glycidylamino group, a diglycidylamino group, and a glycidoxy group. A more preferred molecular structure is an epoxy group-containing compound having a glycidylamino group or a diglycidylamino group, and a glycidoxy group, such as a compound represented by the following general formula (iii).

In the above formula (iii), R is defined in the same manner as R in the above 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 form a cyclic structure, and in that case, it may be in a form in which N bonded to R ⁶ and R are directly bonded. .
In formula (iii), n is an integer of 1 or more, and m is 0 or an integer of 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 modifying agent having a nitrogen atom-containing group is not limited to the following, but includes, for example, N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4 -Glycidoxy-cyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4- Glycidoxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl) Cyclohexane, N,N,N',N'-tetraglycidyl-m-xylene diamine, 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylaniline), ) cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperazinyl)-(N,N- diglycidyl)aniline, 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N,N-diglycidylaniline, 4,4'-diglycidyl-dibenzylmethylamine, N,N- Examples include diglycidylaniline, N,N-diglycidylorthotoluidine, N,N-diglycidylaminomethylcyclohexane, and the like. Among these, particularly preferred are N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

Examples of alkoxysilane compounds that are modifying agents having a nitrogen atom-containing group include, but are not limited to, 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-trimethoxysilane) 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) Examples include methyl-1,6-dioxa-2-silacyclooctane.

Protected amine compounds that can form a primary or secondary amine with a modifying agent having a nitrogen atom-containing group, and compounds that have an unsaturated bond and a protected amine in the molecule, are not limited to the following: However, 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 include 1-[4-N,N-dimethylaminophenyl]ethylene.

Protected amine compounds that can form primary or secondary amines with a modifying agent having a nitrogen atom-containing group, and compounds that have an alkoxysilane and a protected amine in their molecules, are not limited to the following: 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-hexane) 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 -silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, and the like.

Particularly preferred alkoxysilane compounds that are modifying agents having a nitrogen atom-containing group include, but are not limited to, the following, for example, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine , tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3- 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) pentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy) -1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, pentakis(3-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-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane, 1-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane, 1-[3- (2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexane, 3,4,5-tris(3-trimethoxy silylpropyl)-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-silacyclopentane)propyl]phosphate.

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

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

The divalent or higher-valent hydrocarbon group is a saturated or unsaturated hydrocarbon group that may be linear, branched, or cyclic, 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 be a cyclic structure bonded to each other.
Further, when R ³ is a hydrocarbon group, it may be a cyclic structure bonded to R and each other. In the case of the above-mentioned cyclic structure, N bonded to R ³ and R may be directly bonded.
In the formula (i) above, n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

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

(In 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 represents a carbon number 1 to 10 aryl group. 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 a plurality of R ¹ to R ⁴ are present, each of them is independent. )

(In 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 each independently , represents an alkylene group having 1 to 20 carbon atoms.
m, n, and l each independently represent an integer of 1 to 3, and (m+n+l) represents an integer of 4 or more. When a plurality of R ¹ to R ⁶ are present, each of them is independent. )

(In 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 to 20 carbon atoms. R ¹⁹ and R ²² each independently represent an alkylene group having 1 to 20 carbon atoms, and R ²¹ represents an alkyl group or trialkylsilyl group having 1 to 20 carbon atoms.
m represents an integer of 1 to 3, and p represents 1 or 2.
When a plurality of R ¹² to R ²² , m, and p are each independent, they may be the same or different.
i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, and (i+j+k) represents an integer from 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 oxygen atom, nitrogen atom, silicon atom, sulfur atom, and phosphorus atom, and has no active hydrogen. Represents an organic group. )

Modifiers having a nitrogen atom-containing group represented by formula (A) are not limited to the following, but examples include 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza. -2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacycloheptane, 2,2-dimethoxy-1-(3-dimethoxymethyl silylpropyl)-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)- Examples include 1-aza-2-silacyclopentane.
Among these, those in which 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 preferred. 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 modifying agent having a nitrogen atom-containing group represented by the formula (A) with the polymerization active terminal are not particularly limited, but at a temperature of 0°C or more and 120°C or less, It is preferable to react for 30 seconds or more.

The total number of moles of alkoxy groups bonded to silyl groups in the modifying agent compound having a nitrogen atom-containing group represented by formula (A) is the same as that of the alkali metal compound and/or alkaline earth metal compound of the polymerization initiator. It is preferably in a range of 0.6 times or more and 3.0 times or less of the number of moles added, 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 to be within a range of 0 times or less. From the viewpoint of obtaining a sufficient modification rate, molecular weight, and branched structure of the resulting conjugated diene polymer, it is preferable to increase the molecular weight by 0.6 times or more. In addition to the fact that it is preferable to obtain a combined component, from the viewpoint of modifier cost, it is preferable that the amount is 3.0 times or less.
More specifically, the number of moles of the polymerization initiator is preferably 3.0 times or more, more preferably 4.0 times or more, relative to the number of moles of the modifier.

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

The reaction temperature, reaction time, etc. when reacting the modifying agent having a nitrogen atom-containing group represented by the formula (B) with the polymerization active terminal are not particularly limited, but at a temperature of 0°C or more and 120°C or less, It is preferable to react for 30 seconds or more.
The total number of moles of alkoxy groups bonded to silyl groups in the modifier compound represented by formula (B) is 0.6 times or more and 3.0 times the number of moles of lithium constituting the above-mentioned polymerization initiator. It is preferably in the following range, more preferably in the range from 0.8 times to 2.5 times, even more preferably in the range from 0.8 times to 2.0 times. From the viewpoint of obtaining a sufficient modification rate, molecular weight, and branched structure in the conjugated diene polymer, the ratio is preferably 0.6 times or more, and in order to improve processability, the ends of the polymer are coupled together to form a branched polymer. In addition to the fact that it is preferable to obtain the components, from the viewpoint of modifier cost, it is preferable that the amount is 3.0 times or less.
More specifically, the number of moles of the polymerization initiator is preferably 4.0 times or more, more preferably 5.0 times or more, relative to the number of moles of the modifier.

In the formula (C), A is preferably represented by any one 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. When there is a plurality of B ¹ s, each independently )

(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. (B ² and B ³ are independent when there is more than one of each.)

(In formula (IV), B ⁴ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When there is a plurality of B ⁴ s, each independently )

(In formula (V), B ⁵ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and a represents an integer of 1 to 10. When there is a plurality of B ⁵ s, each independently )

In the above formula (C), when A is represented by formula (II), the modifying agent having a nitrogen atom-containing group 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 -Propanediamine, 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-silacyclopentane)propyl]-(3- trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1 -aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-triethoxy silylpropyl)-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-sila) cyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1, 3-Propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-) 1-Sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilyl propyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza- 2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl) -1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethyl Cyclohexane, 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-bis Aminomethylcyclohexane, Tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane) ) propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3 -bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3- (2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1) -Sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane) )propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-diethoxy-1 -aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3- Bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) ) propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl)-1,6-hexamethylenediamine, and pentakis(3-trimethoxysilylpropyl)-diethylenetriamine.

In the above formula (C), when A is represented by formula (III), the modifying agent having a nitrogen atom-containing group 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 '-(propane-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 is mentioned.

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

In the formula (C), A is preferably represented by formula (II) or formula (III), and k represents 0.
Such modifiers having a nitrogen atom-containing group tend to be easily available, and also provide superior wear resistance and low hysteresis loss performance when a conjugated diene polymer is used as a vulcanizate. There is a tendency to Modifiers having a nitrogen atom-containing group include, but are not limited to, the following, 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 , Tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, Tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, Tris(3-trimethoxysilylpropyl)-methyl-1 , 3-propanediamine, and bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trismethoxysilylpropyl)-methyl-1,3-propanediamine. It will be done.

In the formula (C), A is more preferably represented by formula (II) or formula (III), k represents 0, and in formula (II) or formula (III), a is 2 to 10 indicates an integer.
This tends to result in better wear resistance and low hysteresis loss performance upon vulcanization.
Modifiers having a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1, 3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N ¹ -(3-(bis (3-(trimethoxysilyl)propyl)amino)propyl)-N ¹ -methyl-N ³ -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N ³ -(3-( Trimethoxysilyl)propyl)-1,3-propanediamine is mentioned.

The amount of the compound represented by the formula (C) added 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 becomes a desired stoichiometric ratio. Thus, the conjugated diene polymer can be adjusted to react with a 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, relative to the number of moles of the modifier.
In this case, in formula (C), the number of functional groups ((m-1)×i+p×j+k) of the modifier is preferably an integer of 5 to 10, more preferably an integer of 6 to 10.

In the conjugated diene polymer of this embodiment, the proportion of the nitrogen atom-containing polymer in the conjugated diene polymer is expressed as a modification rate.
The modification rate is preferably 60% by mass or more, more preferably 65% by mass or more, even more preferably 70% by mass or more, even more preferably 75% by mass or more, and even more preferably 80% by mass or more.
By setting the modification rate to 60% by mass or more, the processability when forming a vulcanizate tends to be excellent, and the wear resistance and low hysteresis loss performance when forming a vulcanizate tend to be excellent.

In this embodiment, a condensation reaction step in which the condensation reaction is performed in the presence of a condensation promoter may be performed after the coupling step or before the coupling step.

In the conjugated diene polymer of this embodiment, the conjugated diene moiety may be hydrogenated.
The method for hydrogenating the conjugated diene moiety of the conjugated diene polymer is not particularly limited, and any known method can be used.
A suitable hydrogenation method includes a hydrogenation method in which gaseous hydrogen is blown into the polymer solution in the presence of a catalyst.
The catalyst is not particularly limited, but includes, 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 a salt such as nickel or cobalt is solubilized and reacted with an organoaluminium, etc., titanocene, etc. Examples include homogeneous catalysts such as catalysts using metallocenes. Among these, titanocene catalysts are preferred from the viewpoint of being able to select mild hydrogenation conditions.
Further, hydrogenation of aromatic groups can be carried out by using a supported noble metal catalyst.

Hydrogenation catalysts include, but are not limited to, the following: (1) Supported heterogeneous hydrogenation in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc.; Catalyst, (2) So-called Ziegler hydrogenation catalyst using an organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organoaluminum, (3) Ti, Ru, Examples include so-called organometallic complexes such as organometallic compounds such as Rh and Zr. Further, examples of hydrogenation catalysts include, but are not limited to, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-37970, and Japanese Patent Publication No. 1-37970. Also mentioned are known hydrogenation catalysts described in Japanese Patent Publication No. 53851, Japanese Patent Publication 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 polymer of this embodiment, after the coupling step, a deactivator, a neutralizing agent, etc. may be added to the polymer solution as necessary.
Examples of the deactivator include, but are not limited to, water; alcohols such as methanol, ethanol, and isopropanol; and the like.
Examples of the neutralizing agent include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of highly branched carboxylic acids with 9 to 11 carbon atoms, mainly 10 carbon atoms). Acids: Examples include aqueous solutions of inorganic acids and carbon dioxide gas.

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

Aspects of controlling the Mooney viscosity measured at 100°C of the conjugated diene polymer of the present embodiment, improving the productivity of the conjugated diene polymer, and the processability of a rubber composition containing fillers, etc. A rubber softener can be added as needed.
Rubber softeners include, but are not particularly limited to, extender oils, liquid rubbers, resins, and the like.
Methods for adding the rubber softener to the conjugated diene polymer include, but are not limited to, the following methods: adding the rubber softener to the conjugated diene polymer solution, mixing, and adding the rubber softener to the conjugated diene polymer. A method of removing the solvent from the combined solution is preferred.

Preferred extender oils include, for example, aroma oils, naphthenic oils, paraffin oils, and the like. Among these, from the viewpoint of environmental safety, oil bleed prevention and wet grip properties, aromatic alternative oils containing 3% by mass or less of polycyclic aromatic (PCA) components according to the IP346 method are preferred. As aroma substitute oils, TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solva) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999) te), and RAE (Residual Aromatic Extracts).

Preferred liquid rubbers include, but are not limited to, liquid polybutadiene, liquid styrene, etc. Examples include butazine rubber.
The effect of adding liquid rubber is that it not only improves the processability of a rubber composition containing a conjugated diene polymer and filler, but also lowers the glass transition temperature of the rubber composition. The ability to shift tends to improve wear resistance, low hysteresis loss properties, and low-temperature properties when made into a vulcanizate.

Preferred resins include, but are not limited to, aromatic petroleum resins, coumaron/indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, 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, phenolic resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde Resin, xylene-formaldehyde resin, monoolefin oligomer, diolefin oligomer, aromatic hydrocarbon resin, aromatic petroleum resin, hydrogenated aromatic hydrocarbon resin, cycloaliphatic hydrocarbon resin, hydrogenated hydrocarbon resin , hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, esters of hydrogenated oil resins and monofunctional or polyfunctional alcohols, 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 remain.

The effect of adding a resin is to improve the processability of a rubber composition containing a conjugated diene polymer and a filler, as well as to improve the breaking strength of a vulcanizate. Furthermore, by being able to shift the glass transition temperature of the rubber composition to a higher temperature side, there is a tendency to improve wet skid resistance.

The amount of extender oil, liquid rubber, resin, etc. added as a rubber softener 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 this embodiment. , more preferably 5 parts by mass or more and 50 parts by mass or less, still more preferably 10 parts by mass or more and 37.5 parts by mass or less.

When the rubber softener 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 a rubber composition containing the conjugated diene polymer and filler etc. The processability when made into a product tends to be good, and the fracture strength and abrasion resistance when made into a vulcanized product tend to be good.

[Solvent removal process]
In the method for producing a conjugated diene polymer of the present embodiment, a known method can be used to obtain the obtained conjugated diene polymer from a polymer solution. Examples of the method include, but are not particularly limited to, methods of separating the solvent by steam stripping or the like, filtering the polymer, dehydrating and drying it to obtain the polymer, concentrating it in a flushing tank, Further examples include a method of devolatilizing with a vent extruder or the like, and a method of directly devolatilizing with a drum dryer or the like.

(Rubber composition)
The rubber composition of the present embodiment includes a rubber component and 30 parts by mass or more and 150 parts by mass or less of silica based on 100 parts by mass of the rubber component, and the silica has a nitrogen adsorption specific surface area of 180 m ² /g or more. .
Further, the rubber component contains the above-mentioned conjugated diene polymer in an amount of 10% by mass or more based on the total amount of the rubber component, from the viewpoint of improving fuel efficiency, processability, and wear resistance.

<Silica>
The rubber composition of this embodiment contains silica with a nitrogen adsorption specific surface area of 180 m ² /g or more.
Silica with a nitrogen adsorption specific surface area within the above range tends to self-agglomerate and is difficult to disperse, which deteriorates the balance between wear resistance, fracture strength, low hysteresis loss property, and wet skid resistance when made into a vulcanized product. There is a tendency.
On the other hand, the conjugated diene polymer of this embodiment, which has the above-mentioned Mooney viscosity, Mooney relaxation rate, and degree of branching, has a highly branched structure. Since the material having a highly branched structure reduces the viscosity of the rubber composition when shear is applied during kneading, it is possible to further improve the dispersion of silica.
The rubber composition of this embodiment contains 10% by mass or more of the above-mentioned conjugated diene polymer in the rubber component. This improves silica dispersibility. The amount of the conjugated diene polymer based on the total amount of the rubber component is 10% by mass or more, preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more.
Conjugated diene polymers have a high ability to disperse silica and mix well with rubber components, so they function as a so-called "compatibilizer" for dispersing silica throughout the rubber component. Therefore, even if the proportion in the rubber component is about 10% by mass, the dispersibility of silica can be sufficiently improved, and as a rubber composition, the abrasion resistance and fracture strength of the vulcanizate due to the dispersion of silica can be improved. Also, the effect of improving the balance between low hysteresis loss property and wet skid resistance was recognized.

By dispersing silica that satisfies the above-mentioned requirements, the rubber composition of this embodiment tends to have better processability when made into a vulcanizate, and has excellent wear resistance, fracture strength, and Also, they tend to have a better balance between low hysteresis loss and wet skid resistance.

(rubber component)
The rubber component contained in the rubber composition of this embodiment is a rubber-like polymer other than the conjugated diene-based polymer of this embodiment described above (hereinafter simply referred to as "rubber-like polymer"). Can be used in combination with other polymers.
Such rubbery polymers include, but are not limited to, conjugated diene polymers or hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds, or hydrogenated products thereof. Examples include block copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, non-diene polymers, and natural rubber.

Specific rubber-like polymers include, but are not limited to, the following: for example, butadiene rubber or its hydrogenated product, isoprene rubber or its hydrogenated product, styrene-butadiene rubber or its hydrogenated product, styrene-butadiene block. Examples include copolymers or hydrogenated products thereof, styrenic elastomers such as styrene-isoprene block copolymers or hydrogenated products thereof, acrylonitrile-butadiene rubber or hydrogenated products thereof.
Non-diene polymers include, but are not limited to, olefin-based polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber. Elastomers, 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.
Examples of natural rubber include, but are not limited to, smoked sheets RSS No. 3 to 5, SMR, and epoxidized natural rubber.
The various rubbery polymers mentioned above may be modified rubbers to which polar functional groups 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 rubbery polymer is preferably 2,000 or more and 2,000,000 or less, more preferably 5,000 or more and 1,500,000 or less, from the viewpoint of balance between performance and processing characteristics. Furthermore, a low molecular weight rubbery polymer, a so-called liquid rubber, can also be used. These rubbery polymers may be used alone or in combination of two or more.

When the rubber composition of this embodiment is a rubber composition containing the above-mentioned conjugated diene-based polymer and rubber-like polymer, the content ratio (mass ratio) of the above-mentioned conjugated diene-based polymer to the rubber-like polymer. is 10/90 or more and 100/0 or less, preferably 20/80 or more and 90/10 or less, and more preferably 50/50 or more and 80/20 or less (as the above-mentioned conjugated diene polymer/rubber-like polymer). preferable.
Therefore, the rubber component preferably contains 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 90 parts by mass, based on the total amount (100 parts by mass) of the rubber component. Parts or less, 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 abrasion resistance and fracture strength, and has low hysteresis loss property and wet skid resistance. The balance is also satisfactory.

(filler)
In addition to the silica having the specific nitrogen adsorption specific surface area, the filler contained in the rubber composition of the present embodiment may include the following.
For example, silica-based inorganic fillers other than "silica whose nitrogen adsorption specific surface area satisfies 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 preferred.
As the filler, silica may be used alone, or two or more types may be used in combination.

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 based on 100 parts by mass of the rubber component containing the above-mentioned conjugated diene polymer. Part by mass.
By setting the content of the specific silica within the above range, the tire will have excellent handling stability and low hysteresis loss. From the viewpoint of improving handling stability, the amount is preferably 50 parts by mass or more, and more preferably 60 parts by mass or more. Moreover, from the viewpoint of improving low hysteresis loss property, the amount is preferably 120 parts by mass or less, and more preferably 90 parts by mass or less.

The above-mentioned other silica-based inorganic _{fillers are not particularly limited and any known ones can be used, but solid particles containing SiO 2 or Si 3 Al as} a constituent unit are preferable _; More preferred are solid particles contained as the main component of the unit. Here, the main component refers to 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 examples of other silica-based inorganic fillers include, but are not limited to, inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Can be mentioned.
Also included are silica-based inorganic fillers whose surfaces have been made hydrophobic, and mixtures of silica-based inorganic fillers and inorganic fillers other than silica-based fillers.
Among these, silica and glass fiber are preferred, and silica is more preferred, 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 preferred from the viewpoint of improving the breaking strength and having an excellent balance of wet skid resistance.

The rubber composition of this embodiment may contain carbon black. Examples of carbon black include, but are not limited to, carbon blacks of various classes 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 preferred.

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, and 3.0 parts by mass, based on 100 parts by mass of the rubber component containing the conjugated diene polymer. It is more preferably 100 parts by mass or less, and even more preferably 5.0 parts by mass or more and 50 parts by mass or less. In the rubber composition of the present embodiment, the carbon black content is 0.5 parts by mass based on 100 parts by mass of the rubber component, from the viewpoint of achieving the performance required for applications such as tires, such as dry grip performance and conductivity. It is preferably at least 100 parts by mass, and from the viewpoint of dispersibility, it is preferably at most 100 parts by mass based on 100 parts by mass of the rubber component.

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

(Silane coupling agent)
The rubber composition of this embodiment may also contain a silane coupling agent. The silane coupling agent has the function of closely interacting the rubber component and the inorganic filler, and has groups that have affinity or binding properties for the rubber component and the silica-based inorganic filler. , a compound having a sulfur bonding moiety and an alkoxysilyl group or silanol group moiety in one molecule is preferred. Examples of such compounds include, but are not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[3-(triethoxysilyl)-propyl]-disulfide. 2-(triethoxysilyl)-ethyl]-tetrasulfide is mentioned.
In the rubber composition of the present embodiment, the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, and 0.5 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the above-mentioned inorganic filler. It is more preferably 1.0 parts by mass or more and 15 parts by mass or less. When the content of the silane coupling agent is within the above range, the effect of the addition of the silane coupling agent tends to be more pronounced.

(Rubber softener)
In order to improve the processability of the rubber composition of this embodiment, a rubber softener is added in a separate process from the rubber softener added to the conjugated diene polymer and other rubber polymers. May be added.
The amount of the rubber softener to be added is based on 100 parts by mass of the rubber component containing the above-mentioned conjugated diene-based polymer, and the amount of the rubber softener that has been previously contained in the above-mentioned conjugated diene-based polymer or other rubber-like polymer. It is expressed by the amount including the softener and the total amount of the rubber softener added when preparing the rubber composition.
As the rubber softener, mineral oil or a liquid or low molecular weight synthetic softener is suitable.
Mineral oil-based rubber softeners called process oils or extender oils, which are used to soften, increase volume, and improve processability of rubber, are a mixture of aromatic rings, naphthenic rings, and paraffin chains. Those in which the number of carbon atoms in the paraffin chain accounts for 50% or more of the total carbons are called paraffinic, those in which the number of carbon atoms in the naphthene ring accounts for 30% to 45% of the total carbon are called naphthenic, and those in which the number of aromatic carbons is all Carbons that account for more than 30% of carbon are called aromatic. When the conjugated diene polymer of this embodiment is a copolymer of a conjugated diene compound and a vinyl aromatic compound, the rubber softener to be used should be one with an appropriate aromatic content that is compatible with the copolymer. This is preferable because it tends to be good.
In the rubber composition of the present embodiment, the content of the rubber softener is preferably 0 parts by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 90 parts by mass or less, based on 100 parts by mass of the rubber component. More preferably 30 parts by mass or more and 90 parts by mass or less. When the content of the rubber softener is 100 parts by mass or less based on 100 parts by mass of the rubber component, bleed-out tends to be suppressed and stickiness on the surface of the rubber composition is suppressed.

[Method for producing rubber composition]
For methods of mixing conjugated diene polymers and other rubber-like polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, rubber softeners, and other additives, see below. For example, but not limited to, a melt-kneading method using a general mixing machine such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, etc., and dissolving each component. An example of this method is to remove the solvent by heating after mixing. Among these, melt-kneading methods using rolls, Banbury mixers, kneaders, and extruders are preferred from the viewpoint of productivity and good kneading properties. Moreover, either a method of kneading the rubber component, other fillers, silane coupling agents, and additives at once, or a method of mixing them in a plurality of batches can be applied.

The rubber composition of this embodiment may be a vulcanized composition subjected to vulcanization treatment using a vulcanizing agent. Examples of the vulcanizing agent include, but are not limited to, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric 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, based on 100 parts by mass of the rubber component. More preferred. As the vulcanization method, conventionally known methods can be applied, and the vulcanization temperature is preferably 120°C or more and 200°C or less, more preferably 140°C or more and 180°C or less.

During vulcanization, a vulcanization accelerator may be used if necessary. As the vulcanization accelerator, conventionally known materials can be used, including, but not limited to, sulfenamide, guanidine, thiuram, aldehyde-amine, aldehyde-ammonia, and thiazole. , thiourea-based, and dithiocarbamate-based vulcanization accelerators. Further, the vulcanization aid is not limited to the following, but examples thereof include zinc white 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, more preferably 0.1 parts by mass or more and 15 parts by mass or less, based on 100 parts by mass of the rubber component.

The rubber composition of the present embodiment may include other softeners and fillers other than those mentioned above, a heat stabilizer, an antistatic agent, a weather stabilizer, an anti-aging agent, within a range that does not impair the purpose of the present embodiment. Various additives such as colorants and lubricants may also be used. As other softeners, known softeners can be used. Other fillers include, but are not particularly limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. As the above-mentioned heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant, known materials can be used.

〔tire〕
The rubber composition of this embodiment is suitably used as a rubber composition for tires. That is, the tire of this embodiment uses a conjugated diene polymer composition.

Rubber compositions for tires include, but are not limited to, the following: For example, various tires such as fuel-saving tires, all-season tires, high-performance tires, and studless tires: Tire components such as treads, carcass, sidewalls, bead parts, etc. It can be used on the body part. In particular, rubber compositions for tires have an excellent balance between abrasion resistance, breaking strength, low hysteresis loss, and wet skid resistance when made into a vulcanizate. It is suitably 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, a conjugated diene polymer coupled with a modifier is referred to as a "coupled polymer," and a conjugated diene polymer that is not coupled with a modifier is referred to as a "conjugated diene polymer before the coupling reaction." polymer” or “conjugated diene polymer”. Furthermore, these may be collectively referred to as "conjugated diene polymers."

[Physical property measurement method]
(Physical property 1) Polymer Mooney viscosity Conjugated diene polymer before coupling reaction, or conjugated diene polymer coupled with a nitrogen atom-containing modifier (hereinafter also referred to as "coupled conjugated diene polymer") As a sample, Mooney viscosity was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) and 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 the sample, and 100° C. when the sample was the coupled conjugated diene polymer.
Note that for samples that had not undergone the coupling step, measurements were performed at 110°C and 100°C using the manufactured conjugated diene polymer as the sample.
First, after preheating the sample at the test temperature for 1 minute, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured and defined as Mooney viscosity (ML ₍₁₊₄₎ ).

(Physical property 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.), in accordance with ISO 289, After measuring the Mooney viscosity using the rotor, immediately stop the rotation of the rotor, record the torque in Mooney units for 1.6 seconds to 5 seconds after stopping, and record the torque and time (seconds). The slope of the straight line when plotted log-logarithmically was determined, and its absolute value was taken as the Mooney relaxation rate (MSR).

(Physical property 3) Degree of branching (Bn)
The degree of branching (Bn) of the conjugated diene polymer was measured by GPC-light scattering measurement method equipped with a viscosity detector as follows.
Each conjugated diene polymer produced as described below was used as a sample, and a gel permeation chromatography (GPC) measurement device (product name: "GPCmax VE" manufactured by Malvern Co., Ltd.) consisting of three columns connected with polystyrene gel as a packing material was used. The standard Based on polystyrene, the absolute molecular weight was determined from the results of the light scattering detector and the RI detector, and the intrinsic viscosity was determined from the results of the RI detector and the viscosity detector.
The linear polymer was used as having an intrinsic viscosity [η]=-3.883M ^0.771 , and the shrinkage factor (g') as a ratio of the intrinsic viscosity corresponding to each molecular weight was calculated. In addition, in the formula, M represents an absolute molecular weight.
Thereafter, the degree of branching (Bn) defined as g'=6Bn/[(Bn+1)(Bn+2)] was calculated using the obtained contraction factor (g').
Tetrahydrofuran (hereinafter also referred to as "THF") containing 5 mmol/L of triethylamine was used as the eluent.
The columns used were those manufactured by Tosoh Corporation under the trade names "TSKgel G4000HXL,""TSKgelG5000HXL," and "TSKgel G6000HXL."
20 mg of a 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, and measurement was performed under the conditions of an oven temperature of 40° C. and a THF flow rate of 1 mL/min.

(Physical property 4) Molecular weight Measurement conditions 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) consisting of three columns connected with polystyrene gel as a packing material was 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 number average molecular weight ( Mn) and molecular weight distribution (Mw/Mn) were determined.
THF (tetrahydrofuran) containing 5 mmol/L of triethylamine was used as the eluent. Three columns, manufactured by Tosoh Corporation under the trade name "TSKgel SuperMultiporeHZ-H", were connected, and a guard column manufactured by Tosoh Corporation under the trade name "TSKguardcolumn SuperMP (HZ)-H" was connected in front of the column.
10 mg of a measurement sample was dissolved in 10 mL of THF to obtain a measurement solution, and 10 μL of the measurement solution was injected into a GPC measuring device, and measurement was performed under the conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL/min.
Among the various samples measured under measurement condition 1 above, samples whose molecular weight distribution (Mw/Mn) value was less than 1.6 were measured again under measurement condition 2 below.
For samples whose molecular weight distribution value was 1.6 or more when measured under measurement condition 1, measurement was performed under measurement condition 1.
Measurement conditions 2:
Using each conjugated diene polymer produced as described below as a sample, a chromatogram was measured using a GPC measuring device that connected three columns using polystyrene gel as a packing material, and standard polystyrene was used. The weight average molecular weight (Mw) and number average molecular weight (Mn) were determined based on the calibration curve.
THF containing 5 mmol/L of triethylamine was used as the eluent. The columns used were a guard column: "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation, and a column: "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" manufactured by Tosoh Corporation.
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 a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into a GPC measuring device for measurement.
For samples whose molecular weight distribution value was less than 1.6 when measured under measurement condition 1, measurement was performed under measurement condition 2.

(Physical property 5) Modification rate The modification rate of each conjugated diene polymer produced as described below was measured by column adsorption GPC method as follows.
Using a coupled conjugated diene polymer as a sample, measurements were made by applying the property of adsorption of modified basic polymer components to a GPC column using silica gel as a filler.
The amount of adsorption to the silica column is measured from the difference between the chromatogram measured using a polystyrene column and the chromatogram measured using a silica column for a sample solution containing a sample and a low molecular weight internal standard polystyrene, and the denaturation rate is determined. I asked for it.
Specifically, it is as shown below. In addition, for samples whose molecular weight distribution value was 1.6 or more when measured under measurement condition 1 of (Physical Properties 4) above, the following measurement condition 3 was used when the molecular weight distribution value was less than 1.6. Some samples were measured under measurement conditions 4 below.
Preparation of sample solution:
10 mg of the sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF to prepare a sample solution.
Measurement conditions 3: GPC measurement conditions using a polystyrene column:
Using Tosoh Corporation's product name "HLC-8320GPC", 10 μL of the sample solution was injected into the device using THF containing 5 mmol/L triethylamine as the eluent, the column oven temperature was 40°C, and the THF flow rate was 0.35 mL/L. A chromatogram was obtained using an RI detector under the conditions of 10 minutes. Three columns, manufactured by Tosoh Corporation under the trade name "TSKgel SuperMultiporeHZ-H", were connected, and a guard column manufactured by Tosoh Corporation under the trade name "TSKguardcolumn SuperMP (HZ)-H" was connected in front of the column.
Measurement conditions 4: THF containing 5 mmol/L triethylamine was used as the eluent, and 20 μL of the sample solution was injected into the device for measurement. The columns used were a guard column: "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation, and a column: "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" manufactured by Tosoh Corporation. A chromatogram was obtained by measuring 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 silica column:
Using Tosoh Corporation's product name "HLC-8320GPC," 50 μL of the sample solution was injected into the device using THF as the eluent, and RI was performed under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 ml/min. A chromatogram was obtained using a detector. Columns with the product name "Zorbax PSM-1000S", "PSM-300S", and "PSM-60S" are connected and used, and the product name "DIOL 4.6 x 12.5 mm 5 micron" is used as a guard column in the preceding stage. Connected and used.
How to calculate denaturation rate:
The peak area of the sample is P1, the peak area of the standard polystyrene is P2, the total peak area of the chromatogram using the silica column is 100, the total peak area of the chromatogram using the polystyrene column is 100, and the peak area of the sample is P1. The modification rate (%) was determined from the following formula, with the peak area of P3 as P3 and the peak area of standard polystyrene as P4.
Denaturation rate (%) = [1-(P2×P3)/(P1×P4)]×100
(However, P1+P2=P3+P4=100)

(Physical property 6) Amount of bound styrene Using each conjugated diene polymer produced as described below, which does not contain a rubber softener, as a sample, 100 mg of the sample was diluted to 100 mL with chloroform, dissolved, and used as a measurement sample. did.
The amount of bound styrene (mass %) with respect to 100 mass % of the coupled conjugated diene polymer sample was measured based on the absorption amount of ultraviolet absorption wavelength (near 254 nm) by the phenyl group of styrene (measuring device: Shimadzu Corporation) Spectrophotometer "UV-2450" manufactured by Co., Ltd.).

(Physical property 7) Microstructure of butadiene moiety (1,2-vinyl bond amount)
Each conjugated diene polymer containing no rubber softener and manufactured as described below 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 is measured in the range of 600 to 1000 cm ^-1 and the absorbance at a predetermined wave number is determined by Hampton's method (method described in R.R. Hampton, Analytical Chemistry 21, 923 (1949)). The microstructure of the butadiene moiety, that is, the amount of 1,2-vinyl bonds (mol%) was determined according to the calculation formula (measuring device: Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

(Physical property 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 equipped with three columns using polystyrene gel as a packing material, and the solution viscosity was determined. 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: prepared by mixing 5 mL of triethylamine with 1 L of tetrahydrofuran).
The columns were used by connecting a guard column: "TSKguardcolumn HHR-H" manufactured by Tosoh Corporation, and columns: "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 a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 200 μL of the measurement solution was injected into a GPC measuring device for measurement.

[Conjugated diene polymer]
(Coupled conjugated diene polymer (sample 1))
A tank-type reactor with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L/D) of 4.0, an inlet at the bottom, an outlet at the top, and a stirrer. Two tank-type pressure vessels each having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
1,3-butadiene from which water had been removed in advance was mixed at 18.6 g/min, styrene at 10.0 g/min, and n-hexane at 175.2 g/min to obtain a mixed solution. In a static mixer installed in the middle of the pipe that supplies this mixed solution to the inlet of the reaction group, n-butyllithium for inactivating residual impurities was added at a rate of 0.103 mmol/min and mixed, and then added to the bottom of the reaction group. Supplied continuously. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance was mixed vigorously with a stirrer at a rate of 0.081 mmol/min, and n-butyllithium was mixed as a polymerization initiator at a rate of 0.143 mmol/min. The reactor was supplied to the bottom of the reactor, and the reactor internal temperature was maintained at 67°C.
The polymer solution was continuously extracted from the top of the first reactor, continuously supplied to the bottom of the second reactor, where the reaction was continued at 70°C, and further supplied to the static mixer from the top of the second reactor. When the polymerization is sufficiently stable, while copolymerizing 1,3-butadiene and styrene, trimethoxy(4-vinylphenyl)silane (in the table, "BS") is added as a branching agent from the bottom of the second reactive group. -1") was added at a rate of 0.0190 mmol/min to carry out a polymerization reaction and a branching reaction to obtain a conjugated diene polymer having a main chain branched structure. Furthermore, when the polymerization reaction and branching reaction were stabilized, a small amount of the conjugated diene polymer solution before addition of the coupling agent was extracted, and an antioxidant (BHT) was added at a concentration of 0.2 g per 100 g of the polymer. was removed, and the Mooney viscosity at 110°C and various molecular weights were measured. The physical properties 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. The mixture was mixed using a mixer to perform a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 68°C. The difference from the temperature was 2°C. After the coupling reaction, a small amount of the conjugated diene polymer solution is taken out, and an antioxidant (BHT) is added in an amount of 0.2 g per 100 g of the polymer, and then the solvent is removed and the amount of bound styrene (physical property 6) and The microstructure (1,2-vinyl bond amount: physical property 7) of the butadiene moiety was measured. The measurement results are shown in Table 1.
Next, an antioxidant (BHT) was continuously added to the coupling-reacted polymer solution at a rate of 0.055 g/min (n-hexane solution) at a rate of 0.2 g per 100 g of the polymer. The reaction has ended. At the same time as the antioxidant, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added as a rubber softener in an amount of 25.0 g per 100 g of polymer and mixed with a static mixer. .
After removing the solvent by steam stripping, some of the main chains have 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 coupled conjugated diene polymer (Sample 1) having a three-branched star polymer structure derived from a coupling agent was obtained.
Table 1 shows the physical properties of Sample 1. In addition, for the polymer before adding the branching agent, the polymer after adding the branching agent, and the polymer in each step after adding the coupling agent, the molecular weight by GPC measurement and the degree of branching by GPC measurement with a viscometer are calculated. Through comparison, the structure of the coupled conjugated diene polymer was identified. Below, the structure of each sample was similarly identified.

(In formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a portion thereof may have a branched structure.
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 a portion thereof may have a branched structure.
When a plurality of R ¹ to R ³ exist, each of them is independent.
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. )

(Coupled conjugated diene polymer (sample 2))
Example except that 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. In the same manner as 1, a coupled conjugated diene 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. (Sample 2) was obtained. Table 1 shows the physical properties of Sample 2.

(Coupled 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. Other than that, the same procedure as in Example 1 was carried out, with some of the main chains having a 4-branched structure derived from the branching agent structure (1) and a 4-branched star-shaped polymer structure derived from the coupling agent. A conjugated diene polymer (sample 3) was obtained. Table 1 shows the physical properties of Sample 3.

(Coupled conjugated diene polymer (sample 4))
The coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and the addition of The procedure was the same as in Example 1, except that the amount was changed to 0.0360 mmol/min, and some of the main chains had a 4-branched structure derived from the branching agent structure (1), and a 4-branched structure derived from the coupling agent. A coupled conjugated diene polymer (sample 4) having a star-shaped polymer structure was obtained. Table 1 shows the physical properties of Sample 4.

(Coupled 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 amount added was changed to 0.0250 mmol/min. Similarly, a coupled conjugated diene polymer ( Sample 5) was obtained. Table 1 shows the physical properties of Sample 5.

(Coupled 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. Other than that, a coupling agent having a 4-branched structure derived from the branching agent structure (1) in part of the main chain and an 8-branched star-shaped polymer structure derived from the coupling agent was prepared in the same manner as in Example 1. A conjugated diene polymer (Sample 6) was obtained. Table 1 shows the physical properties of Sample 6.

(Coupled 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. Other than that, a coupling agent having a 4-branched structure derived from the branching agent structure (1) in part of the main chain and an 8-branched star-shaped polymer structure derived from the coupling agent was prepared in the same manner as in Example 1. A conjugated diene polymer (sample 7) was obtained. Table 1 shows the physical properties of Sample 7.

(Coupled 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( 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). , abbreviated as "F") and the amount added was changed to 0.0160 mmol/min. A coupled conjugated diene polymer (Sample 8) having a branched structure and an 8-branched star-shaped polymer structure derived from a coupling agent was obtained. Table 1 shows the physical properties of Sample 8.

(Coupled 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( 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). , abbreviated as "F") and the amount added was changed to 0.0160 mmol/min. A coupled conjugated diene polymer (Sample 9) having a branched structure and an 8-branched star polymer structure derived from a coupling agent was obtained. Table 2 shows the physical properties of Sample 9.

(Coupled conjugated diene polymer (sample 10))
The addition rate 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 some of the main chains in the same manner as in Example 1, except that 1,3-propanediamine (abbreviated as "F" in the table) was used and the amount added was changed to 0.0160 mmol/min. A coupled conjugated diene polymer (Sample 10) having a four-branched structure derived from the coupling agent structure (1) and an eight-branched star polymer structure derived from the coupling agent was obtained. Table 2 shows the physical properties of sample 10.

(Coupling conjugated diene polymer (sample 11))
The branching agent was changed from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table), and the amount added was changed to 0.0350 mmol/min. 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 amount added was changed to 0.0360 mmol/min. Similarly, a coupled conjugated diene polymer ( Sample 11) was obtained. Table 2 shows the physical properties of Sample 11.

(Coupling conjugated diene polymer (sample 12))
The branching agent was changed from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table), and the amount added was changed to 0.0350 mmol/min. Changing the ring agent from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table)) and adding it. The procedure was the same as in Example 1 except that the amount was changed to 0.0360 mmol/min, but some of the main chains had a two-branched structure derived from the branching agent structure (1), and a four-branched structure derived from the coupling agent. A coupled conjugated diene polymer (Sample 12) having a star-shaped polymer structure was obtained. Table 2 shows the physical properties of Sample 12.

(Coupling conjugated diene polymer (sample 13))
The branching agent was changed from trimethoxy(4-vinylphenyl)silane to dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table), and the amount added was changed to 0.0350 mmol/min. Except that the ring 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. In the same manner as in Example 1, a coupling conjugate having a two-branched structure derived from the branching agent structure (1) in a part of the main chain and an eight-branched star-shaped polymer structure derived from the coupling agent was prepared. A diene polymer (Sample 13) was obtained. Table 2 shows the physical properties of Sample 13.

(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. 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. In the same manner as in Example 1, except for A coupled conjugated diene polymer (Sample 14) having a 3-branched structure and a 4-branched star polymer structure derived from a coupling agent was obtained. Table 2 shows the physical properties of Sample 14.

(In 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 a plurality of R ² to R ⁵ exist, they are each independent.
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 represents an integer of 0 to 2, b represents an integer of 0 to 3, and c represents an integer of 0 to 3. (a+b+c) indicates 3. )

(Coupled 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. 0120 mmol/min, and the coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table). )), except that the amount added was changed to 0.0360 mmol/min, except that part of the main chain had a tri-branched structure derived from the branching agent structure (2), A coupled conjugated diene polymer (sample 15) having a four-branched star polymer structure derived from a coupling agent was obtained. Table 2 shows the physical properties of Sample 15.

(Coupled 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. 0120 mmol/min, the coupling agent was changed from tetraethoxysilane to tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table), and the amount added was 0.0120 mmol/min. The procedure was the same as in Example 1, except that the rate was changed to 0160 mmol/min, and a part of the main chain had a 3-branched structure derived from the branching agent structure (2), and an 8-branched star-shaped polymer derived from the coupling agent. A coupled conjugated diene polymer (Sample 16) having the following structure was obtained. Table 2 shows the physical properties of sample 16.

(Coupled 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/ Except that 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. In the same manner as in Example 1, a coupling conjugate having a 7-branched structure derived from the branching agent structure (2) in a part of the main chain and a 4-branched star-shaped polymer structure derived from the coupling agent was prepared. A diene polymer (Sample 17) was obtained. Table 3 shows the physical properties of sample 17.

(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/ 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table)). The procedure was the same as in Example 1 except that the addition amount was changed to 0.0360 mmol/min, but some of the main chains had a 7-branched structure derived from the branching agent structure (2), and the coupling A coupled conjugated diene polymer (Sample 18) having a four-branched star-shaped polymer structure derived from the agent was obtained. Table 3 shows the physical properties of Sample 18.

(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/ The procedure was the same as in Example 1, except that some of the main chains had a 7-branched structure derived from the branching agent structure (2), and an 8-branched star-shaped polymer structure derived from the coupling agent. A coupled conjugated diene polymer (Sample 19) was obtained. Table 3 shows the physical properties of Sample 19.

(Coupled 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), the amount added was changed to 0.0190 mmol/min, and coupling was performed. Example 1 except that the 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. Similarly, a coupled conjugated diene polymer (sample 20) was obtained. Table 3 shows the physical properties of sample 20.

(Coupled 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), the amount added was changed to 0.0190 mmol/min, and coupling was performed. 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 was The procedure was the same as in Example 1, except that 0.0360 mmol/min was used, and some of the main chains had a 4-branched structure derived from the branching agent structure (1), and an 8-branched star derived from the coupling agent. A coupled conjugated diene polymer (Sample 21) having a shaped polymer structure was obtained. Table 3 shows the physical properties of Sample 21.

(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), the amount added was changed to 0.0190 mmol/min, and coupling was performed. 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. , in the same manner as in Example 1, a coupled conjugated diene having a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and an 8-branched star-shaped polymer structure derived from the coupling agent. A system polymer (sample 22) was obtained. Table 3 shows the physical properties of sample 22.

(Coupling conjugated diene polymer (sample 23))
The amount of 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 The procedure was the same as in Example 1 except that (3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) was used and the amount added was changed to 0.0190 mmol/min. A coupled conjugated diene polymer (Sample 23) which has a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and has an 8-branched star-shaped polymer structure derived from the coupling agent. I got it. Table 3 shows the physical properties of sample 23.

(Coupled conjugated diene polymer (sample 24))
The amount of 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 tetrakisylsilane. The procedure was the same as in Example 1 except that (3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) was used and the amount added was changed to 0.0190 mmol/min. A coupled conjugated diene polymer (Sample 24) having a 4-branched structure derived from the branching agent structure (1) in some of its main chains and an 8-branched star-shaped polymer structure derived from the coupling agent. I got it. Table 4 shows the physical properties of sample 24.

(Coupled conjugated diene polymer (sample 25))
The amount of 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 tetrakisylsilane. The procedure was the same as in Example 1 except that (3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "F" in the table) was used and the amount added was changed to 0.0190 mmol/min. A coupled conjugated diene polymer (Sample 25) having a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and an 8-branched star-shaped polymer structure derived from the coupling agent. I got it. Table 4 shows the physical properties of sample 25.

(Coupled 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 A coupled conjugated diene polymer (sample 26) was obtained, which had a four-branched structure derived from ) and an eight-branched star-shaped polymer structure derived from a coupling agent. Table 4 shows the physical properties of sample 26.

(Coupled 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) was added to some of the main chains in the same manner as in Example 1, except that the resin (terpene resin YS Resin PX1250, manufactured by Yasuhara Chemical Co., Ltd.) was used instead of the SRAE oil added as a rubber softener. A coupled conjugated diene polymer (sample 27) was obtained, which had a four-branched structure derived from the above-mentioned compound and an eight-branched star-shaped polymer structure derived from the coupling agent. Table 4 shows the physical properties of sample 27.

(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. The procedure was the same as in Example 1, except that the SRAE oil added as a rubber softener was changed to naphthenic oil (naphthenic oil Nytex 810, manufactured by Nynas), with some main chains derived from the branching agent structure (1). A coupled conjugated diene polymer (Sample 28) having a four-branched structure and an eight-branched star polymer structure derived from a coupling agent was obtained. Table 4 shows the physical properties of sample 28.

(Coupled 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. The procedure was the same as in Example 1, except that no rubber softener was added, and some of the main chains had a 4-branched structure derived from the branching agent structure (1), and an 8-branched star derived from the coupling agent. A coupled conjugated diene polymer (sample 29) having a shaped polymer structure was obtained. Table 4 shows the physical properties of sample 29.

(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 some of the main chains in the same manner as in Example 1, except that the amount of SRAE oil added as a rubber softener was changed from 25.0 g to 37.5 g per 100 g of polymer. A coupled conjugated diene polymer (sample 30) having a four-branched structure derived from structure (1) and an eight-branched star-shaped polymer structure derived from the coupling agent was obtained. Table 4 shows the physical properties of sample 30.

(Coupling conjugated diene polymer (sample 31))
A tank-type reactor with an internal volume of 10 L, a ratio of internal height (L) to diameter (D) (L/D) of 4.0, an inlet at the bottom, an outlet at the top, and a stirrer. Two tank-type pressure vessels each having a stirrer and a jacket for temperature control were connected as a polymerization reactor.
1,3-butadiene, from which water had been removed in advance, was mixed at 18.6 g/min, styrene at 10.0 g/min, and n-hexane at 175.2 g/min. In a static mixer installed in the middle of the pipe that supplies this mixed solution to the inlet of the reaction group, n-butyllithium for inactivating residual impurities was added at a rate of 0.103 mmol/min and mixed, and then added to the bottom of the reaction group. Supplied continuously. Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance was mixed vigorously with a stirrer at a rate of 0.081 mmol/min, and n-butyllithium was mixed as a polymerization initiator at a rate of 0.143 mmol/min. The reactor was supplied to the bottom of the reactor, and the reactor internal temperature was maintained at 67°C.
The polymer solution was continuously extracted from the top of the first reactor, continuously supplied to the bottom of the second reactor, where the reaction was continued at 70°C, and further supplied to the static mixer from the top of the second reactor. When the polymerization was sufficiently stabilized, a small amount of the polymer solution before the addition of the coupling agent was taken out, an antioxidant (BHT) was added at a concentration of 0.2 g per 100 g of the polymer, the solvent was removed, and the solution was heated at 110°C. Mooney viscosity and various molecular weights were measured. The physical properties 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. The mixture was mixed using a mixer to perform a coupling reaction. At this time, the time until the coupling agent was added to the polymer solution flowing out from the outlet of the reactor was 4.8 minutes, and the temperature was 68°C. The difference from the temperature was 2°C. After the coupling reaction, a small amount of the conjugated diene polymer solution is taken out, an antioxidant (BHT) is added at a concentration of 0.2 g per 100 g of the polymer, the solvent is removed, and the amount of bound styrene (physical property 6) and The microstructure (1,2-vinyl bond amount: physical property 7) of the butadiene moiety was measured. The measurement results are shown in Table 5.
Next, an antioxidant (BHT) was continuously added to the coupling-reacted polymer solution at a rate of 0.055 g/min (n-hexane solution) at a rate of 0.2 g per 100 g of the polymer. The reaction has ended. At the same time as the antioxidant, as a rubber softener, SRAE oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added in an amount of 25.0 g per 100 g of polymer, and mixed with a static mixer. did. The solvent was removed by steam stripping to obtain a coupled conjugated diene polymer (sample 31) that had no main chain branches derived from the branching agent and had a 3-branched star-shaped polymer structure derived from the coupling agent. . Table 5 shows the physical properties of sample 31.

(Coupling conjugated diene polymer (sample 32))
The coupling agent was changed from tetraethoxysilane to 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane (abbreviated as "D" in the table), and the addition of A coupled conjugated diene having no main chain branching derived from the branching agent and having a four-branched star-shaped polymer structure derived from the coupling agent was prepared in the same manner as Sample 31 except that the amount was changed to 0.0360 mmol/min. A system polymer (sample 32) was obtained. Table 5 shows the physical properties of sample 32.

(Coupled 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. Except for this, a coupled conjugated diene polymer (Sample 33) was obtained in the same manner as Sample 31, having no main chain branching derived from the branching agent and having an 8-branched star-shaped polymer structure derived from the coupling agent. . Table 5 shows the physical properties of Sample 33.

(Conjugated diene polymer (sample 34))
When the polymerization is sufficiently stable, 0.0190 mmol/min of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) is added as a branching agent from the bottom of the second reactive group. The procedure was the same as Sample 31 except that the coupling agent was added at a high speed and no coupling agent was added. A conjugated diene polymer (Sample 34) not showing a star-shaped coupling structure was obtained. Table 5 shows the physical properties of sample 34.
Although sample 34 was not subjected to a coupling reaction, (physical properties 1 to 8) were described in the column of coupled conjugated diene polymer.

(Coupled conjugated diene polymer (sample 35))
When the polymerization is sufficiently stable, 0.0190 mmol/min of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) is added as a branching agent from the bottom of the second reactive group. The procedure was the same as that of 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 coupled conjugated diene polymer (Sample 35), which has a 4-branched structure derived from the branching agent structure (1) in a part of the main chain and a 3-branched star-shaped polymer structure in a part derived from the coupling agent. ) was obtained. Table 5 shows the physical properties of sample 35.

(Coupled conjugated diene polymer (sample 36))
When the polymerization is sufficiently stable, 0.0190 mmol/min of trimethoxy(4-vinylphenyl)silane (abbreviated as "BS-1" in the table) is added as a branching agent from the bottom of the second reactive group. 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 reduced to 0. 0038 mmol/min, except that the sample 31 had a 4-branched structure derived from the branching agent structure (1) in part of the main chain, and a part with an 8-branched star-shaped high-branch structure derived from the coupling agent. A coupled conjugated diene polymer (sample 36) having a molecular structure was obtained. Table 5 shows the physical properties of sample 36.

(Coupling conjugated diene polymer (sample 37))
When the polymerization was sufficiently stabilized, 0.0350 mmol/min of dimethylmethoxy(4-vinylphenyl)silane (abbreviated as "BS-2" in the table) was added as a branching agent 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 Sample 31, except that the amount of the coupling agent tetraethoxysilane was changed from 0.0480 mmol/min to 0.0120 mmol/min. A coupled conjugated diene polymer (Sample 37) having a bi-branched structure derived from (1) and a partially tri-branched star-shaped polymer structure derived from the coupling agent was obtained. Table 5 shows the physical properties of sample 37.

(Coupled 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 added as a branching agent from the bottom of the second reactive group. was added at a rate of 0.0120 mmol/min, and some of the main A coupled conjugated diene polymer (sample 38) was obtained, which had 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. Table 5 shows the physical properties of sample 38.

(Coupling conjugated diene polymer (sample 39))
When the polymerization was sufficiently stabilized, 0% of 1,1-bis(4-trimethoxysilylphenyl)ethylene (abbreviated as "BS-4" in the table) was added as a branching agent from the bottom of the second reactive group. The procedure was the same as Sample 31, except that the coupling agent tetraethoxysilane was added at a rate of 0.0210 mmol/min and the amount of tetraethoxysilane added was changed from 0.0480 mmol/min to 0.0120 mmol/min. A coupled conjugated diene polymer (Sample 39) having a seven-branched structure derived from the branching agent structure (2) and a partially three-branched star-shaped polymer structure derived from the coupling agent was obtained. Table 5 shows the physical properties of sample 39.

(Coupled conjugated diene polymer (sample 40))
When the polymerization was sufficiently stabilized, trichloro(4-vinylphenyl)silane (abbreviated as "BS-5" in the table) was added as a branching agent from the bottom of the second reactive group at a rate of 0.0190 mmol/min. The branching agent structure (1 A coupled conjugated diene polymer (sample 40) was obtained, which had a four-branched structure derived from ) and a partially tri-branched star-shaped polymer structure derived from the coupling agent. Table 5 shows the physical properties of sample 40.

[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 material rubbers, rubber compositions containing the respective raw material rubbers were obtained according to the formulations shown below.

(rubber component)
・Coupled conjugated diene polymer or conjugated diene polymer (Samples 1 to 40)
:80 parts by mass (parts by mass excluding rubber softener)
・High-cis polybutadiene (trade name “UBEPOL BR150” manufactured by Ube Industries, Ltd.)
:20 parts by mass

(Combination conditions)
The amount of each compounding agent added was expressed in parts by mass relative to 100 parts by mass of the rubber component not containing the rubber softener.
・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 "Seest 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 Corporation) Product name “Process NC140”)
: 42.0 parts by mass (including the amount added in advance as a rubber softener contained in Samples 1 to 40)
・Zinc white: 2.5 parts by mass ・Stearic acid: 1.0 parts by mass ・Antioxidant (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 parts by mass・Sulfur: 2.2 parts by mass ・Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide)
: 1.7 parts by mass - Vulcanization accelerator 2 (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 formulation.
・Silica (trade name “Zeosil Premium 200MP” manufactured by Rhodia)
Nitrogen adsorption specific surface area 220m2/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 formulation.
・Silica (trade name “Zeosil Premium 200MP” manufactured by Rhodia)
Nitrogen adsorption specific surface area 220m2/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 formulation.
・Silica (product name: “Ultrasil 9100GR” manufactured by Evonik)
Nitrogen adsorption specific surface area 235m2/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 components were changed as shown below.
(rubber component)
・Coupled conjugated diene polymer (sample 1)
:20 parts by mass (parts by mass excluding rubber softener)
・Styrene-butadiene rubber (trade name “Tufden 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 formulation.
・Silica (trade name “Zeosil Premium 200MP” manufactured by Rhodia)
Nitrogen adsorption specific surface area 220m2/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 formulation.
・Silica (trade name “Zeosil Premium 200MP” manufactured by Rhodia)
Nitrogen adsorption specific surface area 220m2/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 formulation.
・Silica (product name: “Ultrasil 7000GR” manufactured by Evonik)
Nitrogen adsorption specific surface area 175m2/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 components were changed as shown below.
(rubber component)
・Coupled conjugated diene polymer (sample 1)
: 5 parts by mass (parts by mass excluding rubber softener)
・Styrene-butadiene rubber (trade name “Tufden 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 components were changed as shown below.
(rubber component)
・Styrene-butadiene rubber (trade name “Tufden 3835” manufactured by Asahi Kasei Corporation)
: 80 parts by mass ・High-cis polybutadiene (product 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 (inner capacity 0.3L) equipped with a temperature control device, raw rubber (samples 1 to 40), Fillers (silica, carbon black), silane coupling agent, SRAE oil, zinc white and stearic acid were kneaded. At this time, the temperature of the closed mixer was controlled, and each rubber composition (compound) was obtained at a discharge temperature of 155 to 160°C.
Next, in the second stage of kneading, the mixture obtained above was cooled to room temperature, 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 blend was adjusted to 155-160° C. by temperature control of the mixer. After cooling, sulfur and vulcanization accelerators 1 and 2 were added and kneaded using open rolls set at 70° C. as the third stage of kneading. Thereafter, it was molded and vulcanized in a vulcanization press at 160° C. for 20 minutes.
A conjugated diene polymer composition before vulcanization and a conjugated diene 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) Mooney viscosity of the compound The compound obtained above after the second stage kneading and before the third stage kneading was used as a sample, using a Mooney viscometer, and measured at 130°C in accordance with ISO 289. After preheating for 1 minute, the viscosity was measured after rotating the rotor at 2 revolutions per minute for 4 minutes. The results of Comparative Example 1 were set as 100 and indexed. The smaller the index, the better the workability.

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

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

(Evaluation 4) Viscoelastic parameters Viscoelastic parameters were measured in torsion mode using a viscoelasticity tester "ARES" manufactured by Rheometrics Scientific. Each measurement value was expressed as an index, with the result for the rubber composition of Comparative Example 1 set as 100.
Tan δ, which was measured at 0° C. at a frequency of 10 Hz and a strain of 1%, was used as an index of wet grip property. The larger the index, the better the wet grip properties.
Further, tan δ measured at 50° C., frequency of 10 Hz, and strain of 3% was used as an index of fuel efficiency. The smaller the index, the better the fuel efficiency.
Furthermore, 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 lower Mooney viscosity and good processability when made into vulcanizates compared to Comparisons 1 to 15. It was confirmed that the material has excellent abrasion resistance, handling stability, and breaking strength when used, and also has an excellent balance between low hysteresis loss and wet skid resistance.

The rubber composition according to the present invention can be used industrially in fields such as tire treads, interior and exterior parts of automobiles, anti-vibration rubber, belts, footwear, foams, and various industrial products.

Claims (5)

100 parts by mass of a rubber component,
30 to 150 parts by mass of silica having a nitrogen adsorption specific surface area of 180 m ² /g or more,
A rubber composition containing,
The rubber component contains 10% by mass or more of a conjugated diene polymer,
The conjugated diene polymer is
It has a star-shaped polymer structure with three or more branches,
A bicarbonate containing an alkoxysilyl group or a halosilyl group in at least one branch chain of the star-shaped structure.
Bicarbonate having a moiety derived from a vinyl monomer and containing the alkoxysilyl group or halosilyl group
The part derived from the nyl monomer has an additional main chain branched structure,
The portion derived from the vinyl monomer containing the alkoxysilyl group or halosilyl group is
A monomer unit based on a compound represented by the following formula (1) or (2),
Branching point of a polymer chain by a monomer unit based on a compound represented by the following formula (1) or (2)
has
In the formula (1), R ¹ is a hydrogen atom, m = 0,
In the formula (2), m = 0, b = 0,

(In formula (1), R ¹ is a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 6 to 20 carbon atoms.
It represents a lyl group, and a portion thereof may have a branched structure.
R ² to R ³ are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms.
represents a group, and a portion thereof may have a branched structure.
When a plurality of R ¹ to R ³ exist , each of them is independent.
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 formula (2), R ² to R ⁵ are each independently an alkyl group having 1 to 20 carbon atoms or a carbon number 6 to
20 aryl groups, and a portion thereof may have a branched structure. If there are multiple
R ² to R ⁵ are each independent.
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 represents an integer of 0 to 2, b represents an integer of 0 to 3, and c represents an integer of 0 to 3.
(a+b+c) indicates 3. )
Mooney viscosity measured at 100 ° C. is 40 or more and 170 or less,
Mooney relaxation rate measured at 100°C is 0.35 or less,
The degree of branching (Bn) as measured by GPC-light scattering measurement method with a viscosity detector is 8 or more,
Rubber composition. The rubber composition according to claim 1, wherein a modification rate of the conjugated diene polymer measured by column adsorption GPC method is 60% by mass or more. In the formula (1), R ¹ is a hydrogen atom, m = 0, l = 0, and n = 3, a monomer unit based on the compound represented by the formula (1), The rubber composition according to claim 1 , comprising: In the formula (2), m=0, l=0, n=3, a=0, b=0
The rubber composition according to claim 1 , having a monomer unit based on the compound represented by the formula (2), where c=3. A tire containing the rubber composition according to any one of claims 1 to 4 .