JP7405521B2 - Modified conjugated diene polymer, modified conjugated diene polymer composition, and rubber composition - Google Patents

Description

The present invention relates to a modified conjugated diene polymer, a modified conjugated diene polymer composition, and a rubber composition.

In recent years, demands for lower fuel consumption for automobiles have increased, and there has been a demand for improvements in the materials used for automobile tires, especially tire treads that come in contact with the ground. Development is required.
Furthermore, in order to reduce the weight of tires, it is necessary to reduce the thickness of the tire tread, and for this reason, materials with even higher wear resistance are required.
On the other hand, materials used for tire treads are required to have excellent wet skid resistance and practically sufficient breaking strength from the viewpoint of safety.

Materials that meet these demands include materials containing rubber-like polymers and reinforcing fillers such as carbon black and silica.
For example, by using a material containing silica, it is possible to improve the balance between low hysteresis loss and wet skid resistance.
In addition, by introducing a functional group that has affinity or reactivity with silica into the molecular end of a highly mobile rubber-like polymer, the dispersibility of silica in the material can be improved, and furthermore, silica Attempts have been made to reduce the hysteresis loss by reducing the mobility of the end portions of rubbery polymer molecules through bonding with particles.

For example, Patent Documents 1 and 2 propose polymers that are functionalized by reacting a cyclic azasilacycle compound with a polymer active end.
Further, Patent Document 3 proposes a diene rubber obtained by coupling a polymer active end with a polyfunctional silane compound.

Special Publication No. 2008-527150 International Publication No. 11/129425 pamphlet International Publication No. 07/114203 pamphlet

However, in conjugated diene rubber materials containing silica, the affinity between silica and conjugated diene rubber is low because silica has a hydrophilic surface, whereas carbon black has a hydrophobic surface. However, compared to carbon black, it has the disadvantage of poor dispersibility of silica. Therefore, the conjugated diene rubber material containing silica needs to contain a silane coupling agent or the like in order to provide a bond between the silica and the conjugated diene rubber and improve dispersibility.
On the other hand, with conjugated diene rubber materials in which a functional group highly reactive with silica is introduced at the molecular end of the conjugated diene rubber, the reaction with silica particles progresses during the kneading process, but the reaction progresses slowly. However, there are problems in that processability tends to deteriorate, such as insufficient kneading because it takes time to increase the torque, and roughness and sheet breakage when forming sheets after kneading. are doing.
Furthermore, when such a conjugated diene rubber material is made into a vulcanizate, especially when it is made into a vulcanizate containing an inorganic filler such as silica, the balance between low hysteresis loss property and wet skid resistance, and the resistance The problem is that there is room for improvement regarding abrasion resistance.

Therefore, in the present invention, the torque of the mixer is applied well when kneading with the filler, and a rubber composition with good dispersibility of the filler can be obtained in a short time. An object of the present invention is to provide a modified conjugated diene polymer having sufficient processability.

As a result of intensive studies to solve the problems of the prior art described above, the present inventors have discovered a modified conjugated diene polymer in which a functional group having affinity or reactivity with a filler is introduced into the molecule of a conjugated diene polymer. It is a polymer with a weight average molecular weight and molecular weight distribution within a specific range, and is obtained by GPC (gel permeation chromatography) using a column packed with a polar substance that can separate modified components containing functional groups from non-modified components. The modification rate of the modified conjugated diene polymer having a molecular weight corresponding to the peak top molecular weight of the unmodified conjugated diene polymer in the modified conjugated diene polymer is equal to or higher than a predetermined value, and the shrinkage factor (g') The present inventors have discovered that a modified conjugated diene polymer having a specific range of is capable of solving the above-mentioned problems of the prior art, and have completed the present invention. That is, the present invention is as follows.

[1]
The weight average molecular weight is 50 × 10 ⁴ or more and 300 × 10 ⁴ or less,
The molecular weight distribution is 1.77 or more and 4.0 or less,
of unmodified conjugated diene polymers in modified conjugated diene polymers obtained by GPC (gel permeation chromatography) using a column packed with a polar substance that can separate modified components containing functional groups from unmodified components. The modification rate of the modified conjugated diene polymer having a molecular weight corresponding to the peak top molecular weight is 40% by mass or more,
The contraction factor (g') is 0.42 or more and less than 0.64,
100 parts by mass of a modified conjugated diene polymer that contains nitrogen and silicon and is a copolymer of a conjugated diene compound and a vinyl aromatic compound ;
20 parts by mass or less of extension oil;
A modified conjugated diene polymer containing.
[2]
The modified conjugated diene polymer according to the above item [1], wherein the modified conjugated diene polymer has a shrinkage factor (g') of 0.60 or more and less than 0.64.
[3]
The modified conjugated diene polymer according to the above item [1], wherein the modified conjugated diene polymer has a shrinkage factor (g') of 0.42 or more and less than 0.60.
[4]
The modified conjugated diene polymer is
It has a branched structure,
It has nitrogen at the branch point,
has no nitrogen at the end of the polymer chain that is not attached to the modifier residue;
The modified conjugated diene polymer according to any one of [1] to [3] above.
[5]
A modified conjugated diene polymer composition containing 10% by mass or more of the modified conjugated diene polymer according to any one of [1] to [4] above.
[6]
100 parts by mass of a rubbery polymer containing 10% by mass or more of the modified conjugated diene polymer according to any one of [1] to [4] above;
5 parts by mass or more and 150 parts by mass or less of filler,
A rubber composition containing.

According to the present invention, the torque of the mixer is applied well when kneading with the filler, and a rubber composition with good dispersibility of the filler can be obtained in a short time, and further, it is sufficient for practical use even if the amount of extension oil added is reduced. It is possible to provide a modified conjugated diene polymer having excellent processability.

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

[Modified conjugated diene polymer]
The modified conjugated diene polymer of this embodiment is
The weight average molecular weight is 20 × 10 ⁴ or more and 300 × 10 ⁴ or less,
The molecular weight distribution is 1.5 or more and 4.0 or less,
Determination of unmodified conjugated diene polymers in modified conjugated diene polymers obtained by GPC (gel permeation chromatography) using a column packed with a polar substance that can separate modified components containing functional groups from unmodified components. The modification rate of the modified conjugated diene polymer having a molecular weight corresponding to the peak top molecular weight is 40% by mass or more,
It has a contraction factor (g') of 0.42 or more and less than 0.64, and contains nitrogen and silicon.

In this specification, "molecular weight" is a standard polystyrene equivalent molecular weight obtained by GPC (gel permeation chromatography).
The number average molecular weight, weight average molecular weight, and molecular weight distribution can be measured by the methods described in the Examples below.

(Weight average molecular weight)
The modified conjugated diene polymer of the present embodiment has a weight average molecular weight of 20×10 ⁴ or more and 300×10 ⁴ or less, preferably 50×10 ⁴ or more, and more preferably 64×10 ⁴ or more. , more preferably 80×10 ⁴ or more.
Moreover, the weight average molecular weight is preferably 250×10 ⁴ or less, more preferably 180×10 ⁴ or less, and still more preferably 150×10 ⁴ or less.
When the weight average molecular weight is 20×10 ⁴ or more, the balance between low hysteresis loss and wet skid resistance and abrasion resistance when made into a vulcanized product are excellent. Moreover, since the weight average molecular weight is 300×10 ⁴ or less, processability and filler dispersibility when making into a vulcanizate are excellent, and practically sufficient breaking strength can be obtained.
The weight average molecular weight of the modified conjugated diene polymer and the conjugated diene polymer described later can be measured by the method described in the Examples described later.

(molecular weight distribution)
The modified conjugated diene polymer of the present embodiment has a molecular weight distribution Mw/Mn, expressed as a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn), of 1.5 or more and 4.0 or less. A modified conjugated diene polymer having a molecular weight distribution in this range tends to have better processability when made into a vulcanizate compared to a polymer having a similar molecular weight and modification rate. Preferably it is 1.8 or more and 3.0 or less, more preferably 1.9 or more and 2.5 or less.
A modified conjugated diene polymer having such a molecular weight distribution can preferably be obtained by continuous polymerization.
Regarding the molecular weight distribution, it is preferable that the molecular weight curve determined by GPC has a single peak (monomodal) shape, or a trapezoidal or mountain range shape when there are multiple peaks. A mountain range type refers to a shape in which the height of the lowest point between two peaks is 50% or more of the height of the peaks on both sides. Modified conjugated diene polymers having such a molecular weight distribution tend to have better processability when made into a vulcanizate.

In addition, the modified conjugated diene polymer of this embodiment is a modified conjugated diene polymer (hereinafter referred to as "specific (also referred to as "high molecular weight component") is preferably 0.25% by mass or more and 20% by mass or less. As a result, when it is made into a vulcanized product, it tends to have a better balance between low hysteresis loss and wet skid resistance, and a better abrasion resistance.
The content of the specific high molecular weight component is more preferably 1.0% by mass or more and 18% by mass or less, still more preferably 2.0% by mass or more and 15% by mass or less, even more preferably 4.5% by mass or more and 12% by mass or less. % by mass or less. By falling within this range, the abrasion resistance of the vulcanized product tends to be better.
In order to obtain a modified conjugated diene polymer in which the content of the specific high molecular weight component is within such a range, for example, the amount of the organic monolithium compound used as a polymerization initiator described below may be adjusted, or the amount of the organic monolithium compound described below may be adjusted. In the polymerization step, it is preferable to select a method that has a residence time distribution, that is, a method that widens the time distribution of the growth reaction, regardless of whether the polymerization is continuous or batchwise.
Specific methods for the continuous type include a method using a backmix reactor with a tank type reactor equipped with an agitator for vigorous mixing with a stirrer, preferably a method using a complete mixing type reactor, and a method using a tubular reactor. A method of recirculating a part of the reactor, a method of feeding the polymerization initiator to the monomer inlet, or another inlet in the polymerization reactor provided near the monomer inlet, and a method of combining a tank type reactor and a tubular reactor. For example, a method using
In these methods, by increasing the residence time distribution, the polymer component with a long residence time can be made into a high molecular weight component.
In addition, as a specific method in the batch method, for example, regarding the method of feeding the polymerization initiator, continuously or intermittently, at least one of the time from the start of polymerization to the middle of polymerization, the beginning of polymerization, and the middle of polymerization, One method is to feed the data.
In this method, the polymer that starts polymerization from the time when the polymerization initiator is first fed becomes a high molecular weight component, and a difference in molecular weight occurs between it and the polymer that starts polymerization later. More specifically, if the amount of polymerization initiator corresponding to the target molecular weight is continuously fed to the monomer, for example, from 0% to 95% by mass at a conversion rate, an expanded molecular weight distribution can be obtained. There is a tendency that it can be made into a polymer with
By using the above-mentioned method, the activity ratio of the living end of the conjugated diene polymer before the reaction process tends to be high, and the coupling rate after coupling, that is, the modified conjugated diene polymer has a high modification rate. tends to be obtained. Among these methods, a method using a tank-type reactor equipped with an agitator to create a backmix reactor in which vigorous mixing is performed using the agitator is more preferable.

In the modified conjugated diene polymer of the present embodiment, the modification rate relative to the total amount of the conjugated diene polymer is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. It is. Since the modification rate is 50% by mass or more, when it is made into a vulcanized product, it has an excellent balance between low hysteresis loss property and wet skid resistance performance.
The modification rate is the content of a polymer component having a specific functional group in the polymer molecule that has affinity or binding reactivity toward a filler, expressed in mass %, based on the total amount of the conjugated diene polymer.
Preferred examples of the polymer component having a specific functional group in the polymer molecule that has affinity or binding reactivity to a filler include a polymer having a functional group containing a nitrogen atom, a silicon atom, or an oxygen atom. More preferably, it is a modified conjugated diene polymer having the functional group at the end of the polymer. Examples include polymers in which a functional group having a nitrogen atom is bonded to the polymerization initiation terminal and/or modified conjugated diene polymers in which a functional group containing a nitrogen atom, silicon atom, or oxygen atom is bonded to the polymerization termination terminal. It will be done.
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. There are several methods. The selection criteria for columns used here will be described later. More specifically, the denaturation rate is determined by calculating the difference between the chromatogram of a sample solution containing the measurement sample and a low molecular weight internal standard polystyrene using a polystyrene gel column and the chromatogram measured using a silica column. It can be obtained by measuring the amount of adsorption to.
The modification rate can be measured by the method described in the Examples below.
In addition to the method described in the Examples described below, the modification rate may be calculated by adsorbing the modification component onto silica and calculating the change in mass before and after adsorption. Specifically, silica and a modified conjugated diene polymer are added to THF (tetrahydrofuran), and the mixture is stirred for 24 hours to allow the modified component to be adsorbed onto the silica. After stirring, the silica is filtered off, THF is removed from the obtained filtrate using an evaporator, etc., and the mass of unmodified components that are not adsorbed to the silica is measured. The modification rate can be calculated by (mass before silica adsorption−mass of unmodified component)/(mass before silica adsorption)×100.

The criteria for selecting a column for gel permeation chromatography (hereinafter sometimes referred to as a specific column) using a polar substance such as silica as a packing material that adsorbs the specific functional group described above will be described.
A modified conjugated diene polymer whose molecular weight curve determined by GPC has different peaks for modified components and non-modified components is prepared. When measured using a polystyrene gel column, the peaks of the modified component and the non-denatured component are different, so the area ratio of the modified component to the whole can be regarded as the denaturation rate.
Next, calculate the difference between the chromatogram measured with a polystyrene gel column and the chromatogram measured with a specific column for a sample solution containing the same modified conjugated diene polymer and low molecular weight internal standard polystyrene (see the example below). (method described), the denaturation rate is calculated.
If the denaturation rates calculated by the two methods are compared and the error is within 4%, it is determined that the column can be used as a specific column.
Hereinafter, a modified conjugated diene polymer in which the modified component and the unmodified component have different peaks will be described. In order to obtain a modified conjugated diene polymer in which the peaks of the modified component and the unmodified component are different, the molecular weight distribution of the conjugated diene polymer before the modification reaction is small, specifically, 1.0 or more and 1.3 or less. It is preferable that there be. When the polymerization reaction mode is batchwise, it tends to be easier to obtain a conjugated diene polymer having a molecular weight distribution within the above range before the modification reaction. Moreover, since it is preferable that the unmodified component is not adsorbed to a specific column, it is preferable that the polymerization initiator does not have a functional group that is adsorbed to a specific column. Specifically, it is preferable to use n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.
Since it is preferable that the peaks of the modified component and the unmodified component are different and do not overlap, it is preferable that the difference in molecular weight between the modified component and the unmodified component is large. In order to increase the difference in molecular weight, it is preferable to use a modifier that exhibits a large change in molecular weight before and after the modification reaction. That is, it is preferable to use a polybranched modifier. It is preferable to use a modifier that has 3 or more branches, more preferably to use a modifier that has 4 or more branches, and still more preferably to use a modifier that has 6 or more branches.
Further, the modifier needs to have a functional group that adsorbs to a specific column. Specifically, tetraglycidyl metaxylene diamine, tetraglycidylamino diphenylmethane, tetraglycidyl-p-phenylene diamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane, 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, etc., and any modifier that satisfies the above conditions can be used.
It is preferable not to add an excessive amount of the modifier since the peaks of the modified component and the non-modified component may overlap. Specifically, when using a modifier that branches with More preferably, it is 0.8 times or less.

(Modification rate of low molecular weight components)
By measuring the modification rate in each molecular weight region in a molecular weight curve by GPC, the present inventor found that the modification rate differs depending on the molecular weight region depending on the polymer.
Also, it corresponds to the molecular weight at the peak top of the unmodified conjugated diene polymer in the modified conjugated diene polymer obtained by GPC using a column packed with a polar substance that can separate modified components containing functional groups from unmodified components. A modified conjugated diene polymer having a molecular weight of 40% by mass or more (hereinafter sometimes referred to as a low molecular weight component) has a non-uniform modification rate, In particular, it has been found that when the modification rate of the components in the low molecular weight region is 40% by mass or more, it is superior in specific performance compared to a modified conjugated diene polymer containing less than 40% by mass of the low molecular weight components.

In the modified conjugated diene polymer of the present embodiment, the modification rate of the low molecular weight component (hereinafter sometimes referred to as low molecular weight modification rate) in the GPC curve is 40% by mass or more. Preferably it is 45% by mass or more, more preferably 50% by mass or more.
As a result, the modified conjugated diene polymer has good processability, especially when the mixer torque is applied when kneading with the filler, and a rubber composition with good filler dispersibility can be obtained in a shorter time than before. You can get a combination.
As mentioned above, in addition to the knowledge that the modification rate differs depending on the molecular weight range of some polymers, we also discovered the following mechanism for how torque is transmitted during kneading of modified conjugated diene polymers and fillers. As a result, the present invention was completed.

When a modified conjugated diene polymer and a filler are kneaded, the end of the modified polymer reacts with the filler, and the filler is incorporated into the modified conjugated diene polymer, increasing torque. From the viewpoint of steric hindrance, modified conjugated diene polymers with lower molecular weights tend to react more easily with fillers than modified conjugated diene polymers with higher molecular weights. Therefore, the above-mentioned modified conjugated diene polymer with a high modification rate of the low molecular weight component contains a large amount of a modified conjugated diene polymer with a small molecular weight that easily reacts with the filler. Once the reaction occurs, reaction heat is generated, which promotes the reaction between the filler and other modified conjugated diene polymers with large molecular weights, which shortens the overall reaction time and allows the process to be completed in a shorter time than before. It becomes possible to obtain a rubber composition with good filler dispersibility.

Specifically, by increasing the modification rate of low molecular weight components to 40% by mass or more, we are improving processability, especially when mixing with fillers, the torque of the mixer is increased, and the fillers can be dispersed in a shorter time than before. Improves sex. As a result, thermal deterioration that occurs in the polymer during kneading can be minimized, and since thermal deterioration is difficult to occur, the amount of heat stabilizer to be blended can be reduced.

In addition, since the modification rate of the low molecular weight component is 40% by mass or more, when the modified conjugated diene polymer of this embodiment is used as a vulcanized composition, low hysteresis loss property and wet skid resistance are achieved. The degree of freedom in designing a composition is increased in order to obtain a rubber composition that is excellent in balance, breaking strength, and abrasion resistance, and has excellent fuel efficiency especially for use in tires.

The modified conjugated diene polymer of this embodiment can be obtained by a polymerization method that causes very little termination of the growth reaction or chain transfer, and for this purpose, it is effective to ultra-highly purify the monomer and solvent introduced into the polymerization reactor. In addition, low temperature polymerization and a monomer conversion of less than 99% by mass are effective.
Furthermore, the modified conjugated diene polymer of this embodiment is obtained by kneading a modified conjugated diene polymer with a high molecular weight and a predetermined modification rate and a modified conjugated diene polymer with a low molecular weight and a predetermined modification rate. It can also be obtained by doing.

The modification rate for each molecular weight component 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. There are several methods. More specifically, the denaturation rate for each molecular weight component is the molecular weight component of the chromatogram measured using a polystyrene gel column and the chromatogram measured using a silica column for a sample solution containing a measurement sample and a low molecular weight internal standard polystyrene. It can be obtained by measuring the amount of adsorption onto the silica column from the difference between each time. Moreover, the modification rate can be measured by the method described in the Examples below.

The modified conjugated diene polymer of this embodiment has a contraction factor (g') of 0.42 or more and less than 0.64 as measured using 3D-GPC as described later, and has about 6 to 8 branches. It has a structure that includes.
In the case of a polymer with many branches, the range of increase in molecular weight when comparing the polymer before modification and the polymer after modification is larger than that in the case of a polymer with relatively little branching.
As mentioned above, in order to control how torque is applied during kneading, it is desirable to increase the modification rate of relatively low molecular weight components. The inventor has found that it is appropriate to set the peak top molecular weight of the unmodified polymer remaining in the polymer.
This is because, although it is good to use the peak top molecular weight of this unmodified polymer as an index for controlling how torque is applied during kneading, it has not been used in the past, and branched In the case of polymers with a large number of The molecular weight of the subsequent polymer is equivalent to the peak top molecular weight of the unmodified polymer.The amount of the polymer before modification is small, and the highly branched polymer is equivalent to the peak top molecular weight of the unmodified polymer. The modification rate of a component having a molecular weight tends to be low, and setting the "modification rate of a component having a molecular weight corresponding to the peak top molecular weight of an unmodified polymer" to a predetermined value or more is important for the relatively low molecular weight component. This is because the rate of molecular weight modification will be increased.
In order to increase the modification rate of low molecular weight components, it is necessary to further modify the low molecular weight components. For this purpose, it is necessary to reduce the amount of active terminals that are deactivated during polymerization. Therefore, it corresponds to the peak top molecular weight of the unmodified conjugated diene polymer in the modified conjugated diene polymer obtained by GPC using a column packed with a polar substance that can separate modified components containing functional groups from unmodified components. In order to achieve a modification rate of 40% by mass or more of the modified conjugated diene polymer having a molecular weight of It is effective to adopt methods to reduce this.

(contraction factor)
The modified conjugated diene polymer of the present embodiment has a shrinkage factor (g') measured using 3D-GPC of 0.42 or more and less than 0.64, preferably 0.43 or more and 0.63 or less. Yes, more preferably 0.44 or more and 0.60 or less, still more preferably 0.44 or more and 0.59 or less, even more preferably 0.45 or more and 0.57 or less.
A modified conjugated diene polymer having a shrinkage factor (g') within the above range has an excellent balance between processability when made into a vulcanizate, low hysteresis loss property and wet skid resistance when made into a vulcanizate. There is a tendency.
In addition, from the viewpoint of processability, the shrinkage factor (g') is preferably 0.60 or more and less than 0.64, more preferably 0.60 or more and 0.63 or less, and 0.60 or more and 0.62 The following are more preferred. Furthermore, a modified conjugated diene polymer having a shrinkage factor (g') within the above range tends to have an excellent balance between breaking strength and rigidity.
From the viewpoint of further processability, the shrinkage factor (g') is preferably 0.42 or more and less than 0.60, more preferably 0.42 or more and 0.59 or less, and 0.42 or more and 0.55. The following are more preferred.

Since the shrinkage factor (g') tends to depend on the degree of branching, for example, the shrinkage factor (g') can be controlled using the degree of branching as an index.
Specifically, when a modified conjugated diene polymer has 6 branches, its shrinkage factor (g') tends to be 0.59 or more and 0.63 or less, and it has 8 branches. When a modified conjugated diene polymer is used, its shrinkage factor (g') tends to be 0.45 or more and 0.59 or less.
When the shrinkage factor (g') is in the range of 0.45 or more and 0.59 or less, processability when forming a vulcanizate tends to be particularly excellent.

In order to obtain a modified conjugated diene polymer with a shrinkage factor (g') within the above range, for example, a modifier having X (≧5) or more reactive sites with the active terminal is added to the total number of moles of the polymerization initiator. An effective method is to add about 1/X of the number of moles.
The reactive site of the modifier here may be any functional group that reacts with the active end of the polymer, and is not limited to halogenated silyl groups, azasilyl groups, carbonyl groups, epoxy groups, and ester groups. , an alkoxysilyl group. However, the number of reactive points is not the same as the number of functional groups, and when there is one each of halogenated silyl group, azasilyl group, carbonyl group, and epoxy group, it is considered that there is one reactive point, and one ester group is considered to have one reactive point. In this case, it is considered to have two reaction points.
Furthermore, in the case of alkoxysilyl groups, generally all of the alkoxy groups bonded to a silicon atom do not react, and one alkoxy group tends to remain per silicon atom. If there are three, the number of reaction points is 2, if there are two alkoxy groups, the number of reaction points is 1, and if there is one alkoxy group, the number of reaction points is 0.
As the modifier, it is preferable to use a nitrogen-containing alkoxysilyl compound from the viewpoint of processability when forming a vulcanizate, balance between low hysteresis loss property and wet skid resistance when forming a vulcanizate. Specific modifiers will be described later.

As mentioned above, a modifier is selected by counting the reaction points, and an appropriate number of moles of the modifier is added to the total number of moles of the polymerization initiator, and the shrinkage is achieved by reacting with the active end of the polymer. A modified conjugated diene polymer having a factor of 0.42 or more and less than 0.64 is obtained. If the shrinkage factor of the obtained modified conjugated diene polymer is 0.64 or more, it is possible that the amount of the modifier added is not appropriate, specifically, that it is excessive. If the shrinkage factor is less than 0.42, it is necessary to review the structure of the denaturing agent since the shrinkage factor (g') tends to be less than 0.42 when the reaction point exceeds 12.

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') of the modified conjugated diene polymer of the present embodiment is an index of the ratio of the size of the molecule to the linear polymer, which is assumed to have the same absolute molecular weight. That is, as the degree of branching of a polymer increases, the shrinkage factor (g') tends to decrease.
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 . Calculate the shrinkage factor (g') for each absolute molecular weight of the modified conjugated diene polymer, and calculate the average value of the shrinkage factor (g') when the absolute molecular weight is 100 x 10 ⁴ to 200 x 10 ⁴ . Let it be the contraction factor (g') of the modified conjugated diene polymer. Here, "branch" is formed by directly or indirectly bonding one polymer to another polymer. Moreover, "branching degree" is the number of polymers that are directly or indirectly bonded to each other for one branch. For example, when the five conjugated diene polymer chains described below are bonded to each other indirectly via modifier residues described below, it is 5-branched.

(Nitrogen content)
The modified conjugated diene polymer of the present embodiment contains nitrogen, and the content of nitrogen contained in the modified conjugated diene polymer is preferably 3 mass ppm or more and 70 mass ppm or less, more preferably is 6 mass ppm or more and 60 mass ppm or less, more preferably 10 mass ppm or more and 50 mass ppm or less.
When the nitrogen content is 3 mass ppm or more, when it is made into a vulcanizate, it has an excellent balance between low hysteresis loss property and wet skid resistance. When the nitrogen content is 70 mass ppm or less, it is possible to suppress a decrease in rigidity due to excessive dispersion of silica when it is made into a blend.
By employing a nitrogen-containing compound as a modifier, the nitrogen content tends to be 3 mass ppm or more.
On the other hand, when the ratio of nitrogen contained in the modifier is too high, when the amount of nitrogen-containing modifier added is too large relative to the polymer chain, or when nitrogen is bonded to both the polymerization start end and the polymerization end end. etc., there is a tendency for the nitrogen content to exceed 70 mass ppm.
Therefore, by appropriately adjusting the ratio of nitrogen contained in the modifier, the amount of the nitrogen-containing modifier added, and the amount of the modifier bonded to the polymerization terminal, it is possible to reduce the nitrogen content in the modified conjugated diene polymer. can be controlled to 70 mass ppm or less.

(contains silicon)
The modified conjugated diene polymer of this embodiment contains silicon atoms. This tends to lead to better processability when made into a vulcanizate, and a better balance between low hysteresis loss and wet skid resistance when made into a vulcanizate.
Further, it is preferable that at least one silicon atom of this modified conjugated diene polymer constitutes an alkoxysilyl group or silanol group having 1 to 20 carbon atoms. This tends to improve processability, low hysteresis, and wet skid resistance.
The presence of silicon atoms in the modified conjugated diene polymer can be confirmed by metal analysis using the method described in the Examples below.

The modified conjugated diene polymer of this embodiment preferably has a specific functional group that has affinity or binding reactivity to the filler in order to improve the dispersibility of the filler.
Preferably, the specific functional group having affinity or bonding reactivity with the filler includes a functional group containing a nitrogen atom or a silicon atom.
More preferably, the ratio of the number of moles of nitrogen atoms to the number of moles of silicon atoms in the modified conjugated diene polymer, that is, the molar ratio of N/Si, is preferably 0.1 to 10.0, more preferably It is 0.2 to 7.0.
When N/Si is within the above range, the filler is thought to be physically adsorbed by nitrogen during kneading with the filler and chemically bonded by silicon, so it has particularly good affinity with silica-based fillers. A rubber composition using a filler has low hysteresis loss and exhibits good performance as a rubber composition for fuel-efficient tires.
Examples of the functional group containing a silicon atom include, but are not limited to, a methoxysilyl group, an ethoxysilyl group, a propoxysilyl group, and the like.
In addition, examples of the functional group containing a nitrogen atom include, but are not limited to, secondary amino groups, tertiary amino groups, and the like.
Further, the modified conjugated diene polymer of this embodiment is preferably a modified conjugated diene polymer having a functional group containing a nitrogen atom in the polymer molecule. In such a case, the nitrogen atom-containing functional group preferably contains at least a -NH- type secondary amine. In that case, a rubber composition using a silica-based filler and carbon black as a filler has a low hysteresis loss and exhibits good performance as a composition for a fuel-efficient tire.

(Configuration of modified conjugated diene polymer)
The modified conjugated diene polymer of this embodiment preferably has a branched structure.
There may be one branch point, or there may be multiple branch points in one polymer, but in the case where there are multiple branch points, at least one of the branch points is a structural unit derived from a modifier ( (Hereinafter, it may be simply expressed as a modifier residue) and has a functional group that has affinity or reactivity with the filler.
The modified conjugated diene polymer of this embodiment is a modified conjugated diene polymer in which a modifying agent residue having a functional group having affinity or reactivity with a filler is bonded to the polymerization start end and/or end end. It is. That is, the modified conjugated diene polymer of this embodiment consists of a modifier residue having a functional group and a conjugated diene polymer chain.

(modifier residue)
The modifier residue in the modified conjugated diene polymer of this embodiment is a structural unit of the modified conjugated diene polymer that is bonded to the conjugated diene polymer chain, and is, for example, a conjugated diene polymer described below. It is a structural unit derived from a modifier, which is produced by reacting a modifier with a modifier.
The modifier residue has a specific functional group that has affinity or binding reactivity to the filler.
When the modified conjugated diene polymer of this embodiment is a modified conjugated diene polymer in which a functional group is bonded to the polymerization initiation terminal, the modified conjugated diene polymer has a polymerization initiator having a functional group. It can be obtained by carrying out a polymerization reaction using

(end)
It is preferable that the modified conjugated diene polymer of this embodiment has a branched structure and has nitrogen at the branch point and no nitrogen at the terminal.
The "terminus" in the modified conjugated diene polymer of this embodiment refers to the end of the conjugated diene polymer chain that is not bonded to a branch point, for example, a "modifier residue." When a monomer is polymerized using a polymer, and then a modifier is bonded to the end of the polymerization to form a branch point, the modified conjugated diene polymer has a polymer chain that is not bonded to the modifier residue. The terminal has a structural unit derived from a polymerization initiator.
Preferably, the terminal does not contain nitrogen as described above. If nitrogen is contained at the end, even if the final processability of the vulcanizate is the same, the reaction with the filler is rapid and the sheet processability is poor in the early stage of multi-stage kneading. There is a tendency to On the other hand, if the polymer does not contain nitrogen at the terminal end, it reacts with the filler at an appropriate rate, so sheet processability is also good even in the early stages of multi-stage kneading.

(Monomer constituting the conjugated diene polymer)
The conjugated diene polymer before modification of the modified conjugated diene polymer of this embodiment is obtained by polymerizing at least a conjugated diene compound, and if necessary, copolymerizing both a conjugated diene compound and a vinyl aromatic compound. It can be obtained by
The conjugated diene compound is not particularly limited as long as it is a polymerizable monomer, but conjugated diene compounds containing 4 to 12 carbon atoms per molecule are preferred, and conjugated diene compounds containing 4 to 8 carbon atoms are more preferred. It is a compound. Such conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1 , 3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Among these, 1,3-butadiene and isoprene are preferred from the viewpoint of industrial availability. These may be used alone or in combination of two or more.
The vinyl aromatic compound is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene compound, but monovinyl aromatic compounds are preferred. Examples of monovinyl aromatic compounds 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.

(Preferred embodiment for SBR)
When the modified conjugated diene polymer of this embodiment is a butadiene-styrene random copolymer (SBR), the amount of bound styrene is preferably 5% by mass to 50% by mass, and the amount of vinyl bonds is preferably 10 mol% to 75 mol%. preferable. Within this range, SBR that is suitable for all kinds of uses other than tires can be obtained industrially.
In particular, when the bound styrene content is 25% by mass to 45% by mass and the vinyl bond content is 18mol% to 30mol%, a rubber composition with low hysteresis loss and excellent wear resistance can be obtained.
In addition, when the bound styrene content is 18% to 28% by mass and the vinyl bond content is 45mol% to 65mol%, a rubber composition blended with natural rubber can be used for fuel-saving tires with low hysteresis loss and excellent strength. A rubber composition is obtained.
Note that the amount of bound styrene is the mass % of styrene in all monomer components, and the amount of vinyl bonds is mol% of the vinyl bond component in the butadiene component.

(Glass-transition temperature)
The glass transition temperature, or Tg, of the modified conjugated diene polymer of this embodiment is the temperature at which the molecular chain of the modified conjugated diene polymer starts rotational movement, and has a large effect on fuel efficiency and wet grip performance. .
When Tg is low, fuel efficiency is improved, and when Tg is high, wet grip performance is improved.
The modified conjugated diene polymer of the present embodiment preferably has a Tg of -20°C or more and 0°C or less. This results in extremely good wet grip properties and rigidity. This modified conjugated diene polymer is extremely useful for high performance tires and ultra high performance tires.

Another preferable example of the modified conjugated diene polymer of the present embodiment is one having a Tg of -50°C or more and less than -20°C. This results in an extremely excellent balance between fuel efficiency and wet grip. This modified conjugated diene polymer is extremely useful for summer tires and all-season tires.

Further, another preferable form of the modified conjugated diene polymer of the present embodiment is one in which the Tg is -70°C or more and less than -50°C. This results in extremely good low-temperature performance and wear resistance.
This modified conjugated diene polymer is extremely useful for winter tires.
It is also used in the formulation of various tire treads to improve wear resistance.
The Tg of the modified conjugated diene polymer can be controlled within the desired range described above by adjusting the styrene content and/or the amount of 1,2-vinyl bonds. Specifically, Tg can be increased by increasing the styrene content and the amount of 1,2-vinyl bonds.
The Tg of the modified conjugated diene polymer can be measured in accordance with ISO 22768:2006.

(Preferred form of random SBR)
When the modified conjugated diene polymer of the present embodiment is a butadiene-styrene random copolymer (SBR), it is preferable that the proportion of single styrene units is high, and that the number of long styrene chains is small.
Specifically, when the modified conjugated diene-based polymer is a butadiene-styrene copolymer, the modified conjugated diene is removed by an ozonolysis method known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)). When the system polymer was decomposed and the styrene chain distribution was analyzed by GPC, the amount of isolated styrene was 40% by mass or more based on the total amount of bound styrene, and the chain styrene structure with 8 or more styrene chains was 5% by mass. % or less. In this case, the resulting vulcanized rubber can provide a rubber composition for fuel-efficient tires with excellent performance and particularly low hysteresis loss.

(Hydrogenated conjugated diene polymer)
The modified conjugated diene polymer of this embodiment is obtained by further hydrogenating the modified conjugated diene polymer or the conjugated diene polymer before modification in an inert solvent. Good too. This allows all or part of the double bonds to be converted into saturated hydrocarbons. In such a case, heat resistance and weather resistance are improved, product deterioration can be prevented when processed at high temperatures, and the movement performance as a rubber tends to be improved. Moreover, as a result, it exhibits even better performance in various applications such as automotive applications.
The hydrogenation rate of the unsaturated double bond based on the conjugated diene compound can be arbitrarily selected depending on the purpose and is not particularly limited. When used as a vulcanizate, it is preferable that the double bond in the conjugated diene part remains partially. From this point of view, the hydrogenation rate of the conjugated diene moiety in the conjugated diene polymer is preferably 3.0 mol% or more and 70 mol% or less, and preferably 5.0 mol% or more and 65 mol% or less. More preferably, it is 10 mol% or more and 60 mol% or less. In particular, selective hydrogenation of vinyl groups tends to improve heat resistance and athletic performance. The hydrogenation rate can be determined using a nuclear magnetic resonance apparatus (NMR).

(Oil extended polymer, Mooney viscosity)
The modified conjugated diene polymer of this embodiment may be an oil-extended modified conjugated diene polymer to which extender oil is added.
In addition, from the viewpoint of processability when forming a rubber vulcanizate and wear resistance when forming a vulcanizate, the modified conjugated diene polymer of this embodiment has a Mooney viscosity measured at 100°C. It is preferably 20 or more and 100 or less, more preferably 30 or more and 80 or less. Mooney viscosity can be measured by the method described in Examples below.

The amount of extender oil added is preferably 0 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the modified conjugated diene polymer. Preferably it is 0 to 40 parts by mass, more preferably 0 to 35 parts by mass, and even more preferably 0 to 20 parts by mass.
Generally, as the molecular weight increases, the viscosity of the modified conjugated diene polymer increases, leading to manufacturing difficulties and poor processability when forming a vulcanizate. The purpose of adding extender oil is to eliminate manufacturing difficulties and further improve processability when forming a vulcanizate.
However, if too much extender oil is added, wear resistance will deteriorate. In this embodiment, by increasing the degree of branching, the viscosity is significantly lowered compared to a linear conjugated diene polymer with the same molecular weight, and the modification rate of the low molecular weight component described above is reduced to 40% by mass. % or more, the dispersibility of silica improves when it is made into a rubber compound, and it has been found that the amount of extender oil added can be reduced.
Specifically, when the amount of extension oil added is 0 parts by mass or more and 20 parts by mass or less, better wear resistance can be obtained without impairing processability when forming a vulcanizate; When the amount is 30 parts by mass or less, excellent workability and wear resistance tend to be obtained.

(Preferred structure of modified conjugated diene polymer)
The modified conjugated diene polymer of this embodiment is preferably represented by the following general formula (I).

In formula (I), D ₁ represents a diene polymer chain, R ¹ to R ³ each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, and R ⁴ and R ⁷ each Each independently represents an alkyl group having 1 to 20 carbon atoms, R ⁵ , R ⁸ , and R ⁹ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and R ⁶ and R ¹⁰ are Each independently represents an alkylene group having 1 to 20 carbon atoms, and R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.
m and x represent an integer from 1 to 3, x≦m, p represents 1 or 2, y represents an integer from 1 to 3, y≦(p+1), and z is 1 or represents an integer of 2.
When a plurality of D ₁ , R ¹ to R ¹¹ , m, p, x, y, and z are each independent.
i represents an integer from 0 to 6, j represents an integer from 0 to 6, k represents an integer from 0 to 6, (i+j+k) represents an integer from 1 to 10, and ((x×i)+ (y×j)+(z×k)) is an integer from 1 to 30.
A has a hydrocarbon group having 1 to 20 carbon atoms, or at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a silicon atom, a sulfur atom, and a phosphorus atom, and has active hydrogen. Represents an organic group that does not. However, if (i+j+k) is 1, A may be omitted. As a result, when the modified conjugated diene polymer is made into a vulcanizate, it tends to have a better balance between low hysteresis loss and wet skid resistance, and a better abrasion resistance.

In the modified conjugated diene polymer of the present embodiment, A in the formula (I) represents 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, a represents an integer of 1 to 10, and when multiple B ¹ exist, each independently ing.

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 each independent when a plurality of them exist.

In formula (IV), B ⁴ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, and when multiple B ⁴ exist, each independently There is.

In formula (V), B ⁵ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, and when multiple B ⁵ exist, each independently There is. As a result, when it is made into a vulcanized product, it tends to have a better balance between low hysteresis loss and wet skid resistance, and a better abrasion resistance. In addition, it tends to be easier to obtain in practical terms.

[Production method of modified conjugated diene polymer]
The method for producing a modified conjugated diene polymer of the present embodiment preferably includes a polymerization step of polymerizing at least a conjugated diene compound using an organic monolithium compound as a polymerization initiator to obtain a conjugated diene polymer; A modification step of reacting a diene polymer with a modifier having a binding group that reacts with the active end of the conjugated diene polymer and further having a specific functional group having affinity or binding reactivity to a filler; , has.

(Polymerization process)
In the method for producing a modified diene polymer of the present embodiment, preferably, in the polymerization step, at least a conjugated diene compound is polymerized using an organic monolithium compound as a polymerization initiator to obtain a conjugated diene polymer.
In the polymerization step, it is preferable to perform polymerization by a growth reaction of a living anion polymerization reaction, whereby a conjugated diene polymer having an active end can be obtained, and a modified diene polymer with a high modification rate can be obtained in the modification step described later. There is a tendency to be able to obtain a combination.

The modified conjugated diene polymer of this embodiment is a non-modified conjugated diene in a modified conjugated diene polymer obtained by GPC using a column packed with a polar substance that can separate modified components containing functional groups from non-modified components. The modification rate of the modified conjugated diene polymer (low molecular weight component) having a molecular weight corresponding to the peak top molecular weight of the polymer is 40% by mass or more.
In order to obtain such a modified conjugated diene polymer, it is effective to obtain the conjugated diene polymer by a polymerization method that causes very little termination of the growth reaction or chain transfer.
Therefore, it is necessary to achieve ultra-high purity of the monomers and solvents introduced into the polymerization reactor at a higher level than before.
Therefore, the total amount of impurities in the monomer components used is preferably 30 mass ppm or less, and the content concentration (mass) of impurities such as arenes, acetylenes, primary and secondary amines is 20% by mass. The amount of acetylenes is preferably at most 20 ppm by mass, more preferably at most 10 ppm by mass, and the amount of acetylenes is preferably at most 20 ppm by mass, more preferably at most 10 ppm by mass. It is preferable that the total nitrogen content is 4 mass ppm or less, and more preferably 2 mass ppm or less.
Examples of arenes include, but are not limited to, propadiene and 1,2-butadiene. Examples of acetylenes include, but are not limited to, ethyl acetylene and vinyl acetylene. Examples of primary and secondary amines include, but are not limited to, methylamine and dimethylamine.

Ultra-high purification of monomers and solvents can be achieved by thoroughly purifying all monomers and solvents used in polymerization.
In purifying the monomer butadiene, it is important to remove not only polymerization inhibitors but also dimethylamine, N-methyl-γ-aminobutyric acid, etc. that may have an adverse effect on anionic polymerization. As a method for removing these, for example, 1,3-butadiene containing a polymerization inhibitor is washed with low-oxygen water with an oxygen concentration of less than 2 mg/L as washing water, and then 1,3-butadiene is A method for removing a polymerization inhibitor from butadiene may be mentioned.
In purifying the monomer styrene, it is important to remove phenylacetylenes and the like that may have an adverse effect on anionic polymerization. Examples of methods for removing phenylacetylenes include a method of carrying out a hydrogenation reaction using a palladium-supported alumina catalyst.
In purifying n-hexane, which is a polymerization solvent, it is important to remove water that may have an adverse effect on anionic polymerization. Examples of methods for removing this include methods using γ-alumina, synthetic zeolite, and the like. Among these, a method using a synthetic zeolite is preferred, and the synthetic zeolite preferably has a large pore diameter, more preferably a pore diameter of 0.35 nm or more, and even more preferably a pore diameter of 0.42 nm or more.

As a polymerization method in which termination of the growth reaction or chain transfer is extremely small, a method in which the polymerization temperature is controlled and the monomer conversion rate is controlled is effective.
From the viewpoint of stopping the growth reaction or suppressing chain transfer, the lower the polymerization temperature is, the more preferable it is, but from the viewpoint of productivity, the polymerization temperature is preferably a temperature at which living anion polymerization sufficiently proceeds. The temperature is preferably 0°C or higher, and preferably 80°C or lower. More preferably, the temperature is 50°C or higher and 75°C or lower. Further, it is preferable that the conversion rate of the entire monomer is less than 99% by mass when reacting with the modifier. By adding a modifier when the monomer remains in the polymerization vessel and reacting the modifier with the growing polymer chain before the monomer is completely consumed, polymer chains whose terminal ends are not modified can be produced. It is possible to suppress the formation of coalescence and the occurrence of other side reactions. More preferably, the conversion rate is less than 98% by mass.

The conjugated diene polymer may be a random copolymer or a block copolymer. In order to make the conjugated diene polymer into a rubber-like polymer, it is preferable to use the conjugated diene compound in an amount of 40% by mass or more, and preferably 55% by mass or more, based on the total monomers of the conjugated diene polymer. More preferred.
Examples of random copolymers include, but are not limited to, random copolymers made of two or more conjugated diene compounds such as butadiene-isoprene random copolymers, butadiene-styrene random copolymers, and isoprene-styrene random copolymers. Examples include random copolymers and random copolymers of butadiene-isoprene-styrene random copolymers consisting of a conjugated diene and a vinyl-substituted aromatic compound.
The composition distribution of each monomer in the copolymer chain is not particularly limited; for example, a completely random copolymer with a composition close to statistically random, a tapered (gradient) random copolymer with a tapered composition distribution, etc. Examples include copolymers. The bonding mode of the conjugated diene, ie, the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or may be distributed.
The block copolymer is not limited to the following, but includes, for example, a type 2 block copolymer (diblock) consisting of two blocks, a type 3 block copolymer (triblock) consisting of three blocks, and a type 3 block copolymer consisting of three blocks (triblock). A type 4 block copolymer (tetra block) consisting of The polymer constituting one block may be a polymer made of one type of monomer or a copolymer made of two or more types of monomers. For example, a polymer block consisting of 1,3-butadiene is represented by "B", a copolymer of 1,3-butadiene and isoprene is represented by "B/I", a copolymer of 1,3-butadiene and styrene is is represented by "B/S" and a polymer block made of styrene is represented by "S", BB/I2 type block copolymer, BB/S2 type block copolymer, S-B2 type block Copolymer, BB/S-S3 type block copolymer, S-B-S3 type block copolymer, S-B-S-B4 type block copolymer, etc.
In the above equation, the boundaries of each block do not necessarily need to be clearly distinguished. In addition, when one polymer block is a copolymer consisting of two types of monomers A and B, A and B in the block may be uniformly distributed or tapered. good.

<Polymerization initiator>
As the polymerization initiator used in the polymerization step, it is preferable to use at least an organic monolithium compound.
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 the organic monolithium compound include compounds having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond in terms of the bonding mode between the organic group and the lithium.
In addition, from the viewpoint of sheet processability, the modified conjugated diene polymer of this embodiment does not have a modified structure at both ends, that is, it has nitrogen at the branch point and preferably has a structure without nitrogen. In order to avoid such a structure in which both ends are modified, it is preferable to use a polymerization initiator that does not contain nitrogen.
The amount of the organic monolithium compound used as a polymerization initiator can be appropriately determined depending on the molecular weight of the target conjugated diene polymer or modified conjugated diene polymer. The amount of a monomer such as a conjugated diene compound used relative to the amount of a polymerization initiator used tends to be related to the degree of polymerization, that is, to the number average molecular weight and/or weight average molecular weight. Therefore, in order to increase the molecular weight of the conjugated diene polymer, it is preferable to adjust the amount of polymerization initiator to decrease, and to decrease the molecular weight, it is preferable to adjust to increase the amount of polymerization initiator. .

Examples of the organic monolithium compound include an alkyllithium compound having a substituted amino group or dialkylaminolithium. 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 a substituted amino group without active hydrogen include, but are not limited to, the following: 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, 4-dimethylaminopropyllithium, 4-(methylpropylamino)butyllithium, - Hexamethyleneiminobutyllithium.
Examples of the alkyllithium compound having a substituted 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, 1-lithio-1,2,3 , 6-tetrahydropyridine.

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 form solubilized oligomeric organic monolithium compounds. It can also be used as a compound.
Preferably, the organic monolithium compound serving as the polymerization initiator includes an alkyllithium compound. 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.

Moreover, the organomonolithium compound may be used in combination with other organometallic compounds.
Examples of the organometallic compound include, but are not limited to, alkaline earth metal compounds, alkali metal compounds other than lithium, and other organometallic compounds.
Examples of alkaline earth metal compounds include, but are not limited to, organic magnesium compounds, organic calcium compounds, and organic strontium compounds. Also included are alkaline earth metal alkoxide, sulfonate, carbonate, and amide compounds. Examples of the organic magnesium compound include dibutylmagnesium and ethylbutylmagnesium. Examples of other organometallic compounds include organoaluminum compounds.

The polymerization reaction mode in the polymerization step is not limited to the following, but includes, for example, batch type (also referred to as "batch type") and 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, a monomer, an inert solvent, and a polymerization initiator are continuously fed into a reactor, a polymer solution containing a polymer is obtained in the reactor, and a polymer solution is continuously fed into a reactor. The 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, and the polymer is contained in the reactor. A polymer solution is obtained, and the polymer solution is discharged after the polymerization is completed.
In the manufacturing process of the modified conjugated diene polymer of this embodiment, in order to obtain a conjugated diene polymer having a high proportion of active terminals, the polymer must be continuously discharged and subjected to the next reaction in a short time. It is preferable to carry out the polymerization step in a continuous manner that allows for.

In the polymerization step, it is preferable to carry out the polymerization in an inert solvent.
Examples of the inert solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons.
Examples of hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; Hydrocarbons include aromatic hydrocarbons such as benzene, toluene, xylene, and 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 vinyl aromatic compound and the conjugated diene compound to be randomly copolymerized, and the polar compound tends to be used as a vinylizing 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, Examples include alkali metal alkoxide compounds such as sodium amylate; phosphine compounds such as triphenylphosphine; and the like.
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 portion of the 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 conjugated diene polymer obtained in the polymerization step and before the reaction step described below preferably has a Mooney viscosity measured at 110° C. of 10 or more and 90 or less, more preferably 15 or more and 85 or less, and even more preferably is 20 or more and 60 or less.
When the Mooney viscosity is within the above range, the modified conjugated diene polymer of this embodiment tends to have excellent processability and wear resistance.

The amount of bound conjugated diene in the modified conjugated diene polymer of this embodiment is not particularly limited, but is preferably 40% by mass or more and 100% by mass or less, more preferably 55% by mass or more and 80% by mass or less. preferable.
Further, the amount of bonded vinyl aromatics in the modified 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 20% by mass or more and 45% by mass or less. It is more preferable.
When the amount of bonded conjugated diene and the amount of bonded vinyl aromatic are within the above ranges, when made into a vulcanized product, the balance between low hysteresis loss property and wet skid resistance, fracture strength and abrasion resistance are more excellent. There is a tendency.
Here, the amount of bonded vinyl aromatics 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 can be measured according to the method described in Examples described later.

In the modified 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 made into a vulcanized product. Here, when the branched-modified diene polymer is a copolymer of butadiene and styrene, the butadiene bonding unit is removed by Hampton's method (RR. Hampton, Analytical Chemistry, 21, 923 (1949)). The vinyl bond amount (1,2-bond amount) can be determined. Specifically, it can be measured by the method described in Examples below.

Regarding the microstructure of the modified conjugated diene polymer, the amount of each bond in the modified conjugated diene polymer of this embodiment is within the numerical range mentioned above, and the glass transition temperature (Tg) of the modified conjugated diene polymer is When the temperature is in the range of -50°C or more and less than -20°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.
Another preferable example of the modified conjugated diene polymer is one having a Tg of -20°C or more and 0°C or less. This results in extremely good wet grip properties and rigidity.
Further, another preferable form of the modified conjugated diene polymer of the present embodiment is one having a Tg of -70°C or more and less than -50°C. This results in extremely good low-temperature performance and wear 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. Specifically, it can be measured by the method described in Examples below.

When the modified conjugated diene polymer of this embodiment is a conjugated diene-vinyl aromatic copolymer, the number of blocks in which 30 or more vinyl aromatic units are chained together may be small or absent. preferable. More specifically, when the copolymer is a butadiene-styrene copolymer, Kolthoff's method (method described in IM. KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)) 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 vinyl aromatic units are chained is preferably 5.0% based on the total amount of the copolymer. It is not more than 3.0% by mass, more preferably not more than 3.0% by mass.

(denaturation process)
In the modification step, the conjugated diene polymer obtained by the method described above is used, and the conjugated diene polymer has a bonding group that reacts with the active end of the conjugated diene polymer, and also has affinity or bonding reactivity to the filler. React with a modifier having a predetermined functional group.
Moreover, it is preferable to carry out the modification step immediately after the polymerization step. In that case, a modified conjugated diene polymer with a high modification rate tends to be obtained.
When a compound with a monofunctional or difunctional bonding group is used as a modifier, a linear terminal-modified diene polymer is obtained, and when a polyfunctional compound with a trifunctional or more bonding group is used, a branched modified diene polymer is obtained. A diene polymer is obtained.
The modifier preferably contains nitrogen, and may also contain silicon, tin, oxygen, sulfur, and halogen. Furthermore, an onium structure can be introduced into the modified conjugated diene polymer by adding and reacting a terminal modifier containing an onium generating agent. Furthermore, a modifier containing a plurality of functional groups containing these elements in a molecule, or a modifier containing a functional group containing a plurality of these elements can also be used.
As the modifier, those having functional groups with little or no active hydrogen, such as hydroxyl groups, carboxyl groups, primary and secondary amino groups, are preferred. Active hydrogen tends to deactivate the active end of the conjugated diene polymer.

The reaction temperature in the modification step is preferably the same temperature as the polymerization temperature of the conjugated diene polymer, particularly preferably a temperature at which no heating is performed after polymerization. The temperature is more preferably 0°C or more and 120°C or less, and even more preferably 50°C or more and 100°C or less.
The reaction time in the modification step is preferably 10 seconds or more, more preferably 30 seconds or more.
For mixing in the modification step, any mixing method such as mechanical stirring or stirring using a static mixer may be applied. When the polymerization step is continuous, it is preferable that the modification step is also continuous. The reactor used in the modification step is, for example, a tank type or a tube type with a stirrer. The modifier may be diluted with an inert solvent and fed continuously to the reactor. When the polymerization process is a batch process, the modifier may be introduced into the polymerization reactor, or the reaction process may be performed by transferring the modifier to another reactor.

<Specific description of modifier>
Modifiers include, but are not limited to, 1,3,5-tris(trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(triethoxysilylpropyl)isocyanurate, N-( methoxycarbonylethyl)-N,N-bis(3-trimethoxysilylpropyl)amine, N-(ethoxycarbonylethyl)-N,N-bis(3-triethoxysilylpropyl)amine, N-(methoxycarbonylpropyl) -N,N-bis(3-trimethoxysilylpropyl)amine, N-(ethoxycarbonylpropyl)-N,N-bis(3-triethoxysilylpropyl)amine, and the like.
The modifier preferably has a nitrogen- and silicon-containing functional group, and more preferably the silicon-containing functional group has an alkoxysilyl group or a silanol group.
For example, the alkoxysilyl group of the modifier reacts with the active end of the conjugated diene polymer, dissociating the alkoxylithium, and causing the bond between the end of the conjugated diene polymer chain and the silicon of the modifier residue. tend to form. The value obtained by subtracting the number of SiORs reduced by the reaction from the total number of SiORs that one molecule of the modifier has is the number of alkoxysilyl groups that the modifier residue has. Further, the azasilacycle group possessed by the modifier forms a >N-Li bond and a bond between the terminal of the conjugated diene polymer and the silicon of the modifier residue. Note that >N—Li bonds tend to easily become >NH and LiOH due to water during finishing. Furthermore, in the modifier, unreacted remaining alkoxysilyl groups tend to easily become silanol (Si--OH groups) due to water during finishing.

If the modifier has a structure in which nitrogen atoms and silicon atoms are directly bonded, the following reaction tends to occur when the modified polymer is brought into contact with water, so the polymer after solvent separation tends to The desired degree of branching may not be achieved. In that case, it is preferable to finish using a method that does not use water.
((RO)-Si-D ₂ ) ₃ -N+H ₂ O→3((RO)-Si(OH)-D ₂ )+NH ₃
(In the above formula, D represents a diene polymer, and R represents a single bond or an alkyl group having 1 to 20 carbon atoms.)
In the modification step, when a modifier having three alkoxy groups per silicon atom is used, that is, when 1 mole of trialkoxysilane group is reacted with 3 moles of the active end of the conjugated diene polymer, Although reaction with up to 2 moles of the conjugated diene polymer occurs, 1 mole of the alkoxy group tends to remain unreacted. This is confirmed from the fact that 1 mole of the conjugated diene polymer did not react and remained as an unreacted polymer. Note that by reacting a large amount of alkoxy groups, it tends to be possible to suppress large changes in polymer viscosity due to condensation reactions occurring during finishing and storage. Preferably, a modifier having one alkoxysilyl group per silicon atom is used.

As the modifier, a compound represented by the following general formula (VI) is preferred.

In formula (VI), 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 a group having 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.
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 1 to 10.
A has a single bond, 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 contains active hydrogen. Represents an organic group that does not have
The hydrocarbon group represented by A includes saturated, unsaturated, aliphatic, and aromatic hydrocarbon groups. The organic group having no active hydrogen is an organic group that inactivates the active end of the conjugated diene polymer. The organic groups include hydroxyl groups (-OH), secondary amino groups (>NH), primary amino groups (-NH ₂ ), and sulfhydryl groups (-SH), which do not have active hydrogen-containing functional groups. It is the basis. Note that if (i+j+k) is 1, A may be omitted.
In the formula (VI), A preferably represents 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, a represents an integer of 1 to 10, and when multiple B ¹ exist, each independently ing.

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 each independent when a plurality of them exist.

In formula (IV), B ⁴ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, and when multiple B ⁴ exist, each independently There is.

In formula (V), B ⁵ represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, and when multiple B ⁵ exist, each independently There is.

In the above formula (VI), when A represents one of the following general formulas (II) to (V), it tends to be possible to obtain a modified conjugated diene polymer having better performance. .

The modifier when A is represented by formula (II) in formula (VI) is not limited to the following, but examples include tris(trimethoxysilyl)amine, tris(triethoxysilyl)amine, tris( 3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2, 2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] Amine, tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3- (2,2-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-silacyclo) pentane)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-silacyclo) pentane)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-propane Diamine, Tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl ]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy) -1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-aza) cyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-( 1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl ]-(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2, 2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis (3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl] -1,3-bisaminomethylcyclohexane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisamino Methylcyclohexane, 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-bis Aminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-triethoxysilylpropyl)-1,3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1 -aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl)-bis[3-(2,2-diethoxy-1-aza-2-silacyclo) pentane)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 is mentioned.

The modifier when A is represented by formula (III) in formula (VI) 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-triethoxysilylpropyl)-methyl-1,3 -Propanediamine, bis(2-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3- (2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, N ¹ ,N ¹ '-(propane-1, 3-diyl)bis(N ¹ -methyl-N ³ ,N ³ -bis(3-(trimethoxysilyl)propyl)-1,3-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.

In formula (VI), when A is represented by formula (IV), the modifier is not limited to the following, but for example, tetrakis[3-(2,2-dimethoxy-1-aza-2-silyl) cyclopentane)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-azacyclopentane)propyl]silane are mentioned. It will be done.

In formula (VI), when A is represented by formula (V), the modifier 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.

In formula (VI), A is preferably represented by formula (II) or formula (III), and k represents 0. Such modifiers tend to be easily available, and also tend to provide better wear resistance and low hysteresis loss performance when the modified conjugated diene polymer is used as a vulcanizate. Such modifiers 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-tri methoxysilylpropyl)-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.

In formula (VI), 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. Examples of such modifiers 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-(trimethoxy silyl)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 formula (VI) as a modifier can be adjusted so that the number of moles of the conjugated diene polymer to the number of moles of the modifier is reacted in a desired stoichiometric ratio. , thereby tending to achieve the desired degree of branching. Specifically, the number of moles of the polymerization initiator 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 (VI), the number of modified functional groups ((m-1)×i+p×j+k) is preferably an integer of 5 to 10, more preferably an integer of 6 to 10.

(Hydrogenation process)
The modified conjugated diene polymer of this embodiment may be one in which the conjugated diene moiety is hydrogenated. The method for hydrogenating the conjugated diene moiety 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.
As a catalyst, 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., or a metallocene such as titanocene is used. Examples include homogeneous catalysts such as catalysts. 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, as a hydrogenation catalyst, for example, Japanese Patent Publication No. 42-8704, Japanese Patent Publication No. 43-6636, Japanese Patent Publication No. 63-4841, Japanese Patent Publication No. 1-37970, Japanese Patent Publication No. 1-53851, Also mentioned are known hydrogenation catalysts described in Hei 2-9041 and JP-A-8-109219. Preferred hydrogenation catalysts include reaction mixtures of titanocene compounds and reducing organometallic compounds.

(Other processes)
In the manufacturing process of the modified conjugated diene polymer of the present embodiment, a deactivator, a neutralizing agent, etc. may be added to the modified conjugated diene polymer solution as necessary after the modification step.
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.

It is preferable to add a rubber stabilizer to the modified conjugated diene polymer of this embodiment from the viewpoint of preventing gel formation after polymerization and from the viewpoint of improving stability during processing.
As the rubber stabilizer, known stabilizers can be used, including, but not limited to, 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl- Examples of antioxidants include 3-(4'-hydroxy-3',5'-di-tert-butylphenol)propinate and 2-methyl-4,6-bis[(octylthio)methyl]phenol.

In order to further improve the processability of the modified conjugated diene polymer of this embodiment, if necessary, extending oil may be added to the modified conjugated diene polymer to obtain an oil-extended modified conjugated diene polymer. can.
The method of adding the extender oil to the modified conjugated diene polymer is not limited to the following method, but the extender oil is added to the polymer solution and mixed to form an oil extended copolymer solution, which is then desolvated. A method of doing so is preferred.
Examples of the extender oil include aroma oil, naphthenic oil, paraffin oil, 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. Other examples include oils derived from vegetable oils, such as "Vivamax 5000" and "Vivamax 5100" manufactured by H&R.
As aroma substitute oils, TDAE (Treated Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999) are used. ), as well as RAE (Residual Aromatic Extracts).
The amount of extension oil added is not particularly limited, but is preferably 0 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the modified conjugated diene polymer. Preferably it is 0 to 40 parts by mass, more preferably 0 to 35 parts by mass, and even more preferably 0 to 20 parts by mass.
Moreover, from the viewpoint that processability deteriorates if the amount of extender oil added is too small, it is preferably more than 20 parts by mass and 30 parts by mass or less.

A known method can be used to obtain the modified conjugated diene polymer of this embodiment from a polymer solution. Examples of this method include separating the solvent by steam stripping, filtering the polymer, dehydrating and drying it to obtain a polymer, concentrating it in a flushing tank, and then using a vent extruder. Examples include a method of devolatilizing with a drum dryer, and a method of directly devolatilizing with a drum dryer.
However, if a modifier in which silicon is directly bonded to the nitrogen atom is used, reactions with water as shown below tend to occur easily, so a method that does not use water is preferred.
((RO)-Si-D ₂ ) ₃ -N+H ₂ O→3((RO)-Si(OH)-D ₂ )+NH ₃
(In the above formula, D represents a diene polymer, and R represents a single bond or an alkyl group having 1 to 20 carbon atoms.)
Examples of methods that do not use water include a method of concentrating in a flushing tank and further devolatilizing with a vent extruder or the like, and a method of directly devolatilizing with a drum dryer or the like.

[Modified conjugated diene polymer composition]
The modified conjugated diene polymer composition of the present embodiment (hereinafter sometimes referred to as a polymer composition) contains 10% by mass or more of the modified conjugated diene polymer of the present embodiment.
The polymer composition of this embodiment may contain a polymer other than the modified conjugated diene polymer of this embodiment.
Polymers other than the modified conjugated diene polymer of this embodiment include rubbery polymers having structures other than the modified conjugated diene polymer of this embodiment (hereinafter referred to as "other rubbery polymers"). ), or resinous polymers.
Other rubber-like polymers include, but are not limited to, the following: for example, conjugated diene polymers or hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds, or hydrogenated products thereof. , a block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof, a non-diene polymer, and natural rubber. Specific examples of other rubbery polymers include, but are not limited to, butadiene rubber or its hydrogenated product, isoprene rubber or its hydrogenated product, styrene-butadiene rubber or its hydrogenated product, styrene-butadiene rubber or its hydrogenated product, and styrene-butadiene rubber or its hydrogenated product. Examples include styrenic elastomers such as butadiene block copolymers or hydrogenated products thereof, styrene-isoprene block copolymers or hydrogenated products thereof, acrylonitrile-butadiene rubber or hydrogenated products thereof.
The non-diene polymers include, but are not limited to, olefins 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, polysulfide rubber can be mentioned.
Examples of the natural rubber include, but are not limited to, smoked sheets RSS No. 3 to 5, SMR, and epoxidized natural rubber.

As a method of mixing the modified conjugated diene polymer of this embodiment and a polymer other than the modified conjugated diene polymer of this embodiment (referred to as other polymer), a solution of the modified conjugated diene polymer and a polymer other than the modified conjugated diene polymer of this embodiment are mixed. Various methods can be used, such as a method of mixing a solution of another polymer and a method of mechanically mixing a modified conjugated diene polymer with another polymer.
The other polymer mentioned above may be a modified rubber provided with a polar functional group such as a hydroxyl group or an amino group. When used for tires, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber are preferably used.
When the other polymer is the above-mentioned "other rubbery polymer", its weight average molecular weight is preferably 2,000 or more and 2,000,000 or less from the viewpoint of the balance between performance and processing characteristics, More preferably, it is 5,000 or more and 1,500,000 or less. Furthermore, a low molecular weight rubbery polymer, a so-called liquid rubber, can also be used. These other rubbery polymers may be used alone or in combination of two or more.

When the polymer composition of this embodiment is a composition containing the modified conjugated diene polymer of this embodiment and another rubbery polymer, the modification of this embodiment to the other rubbery polymer The content ratio (mass ratio) of the conjugated diene polymer (modified conjugated diene polymer/other rubbery polymer) is preferably 10/90 or more and 100/0 or less, and 20/80 or more and 90/10 or less. is more preferable, and even more preferably 50/50 or more and 80/20 or less. Therefore, the composition preferably contains 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass, of the modified conjugated diene polymer of the present embodiment based on the total amount (100 parts by mass) of the composition. Parts by weight or more and 90 parts by weight or less, more preferably 50 parts by weight or more and 80 parts by weight or less.
When the content ratio of (modified conjugated diene polymer/other rubbery polymer) is within the above range, when it is made into a vulcanized product, it has an excellent balance between low hysteresis loss property and wet skid resistance, and has excellent wear resistance. The durability and breaking strength are also satisfactory.

The modified conjugated diene polymer of this embodiment is suitably used as a vulcanizate. Applications of the vulcanizate include, for example, tires, hoses, shoe soles, anti-vibration rubber, automobile parts, and anti-vibration rubber, as well as rubber for reinforcing resins such as impact-resistant polystyrene and ABS resin. In particular, modified conjugated diene polymers are suitably used in tread rubber compositions for tires. For example, the vulcanizate may include the modified conjugated diene polymer of this embodiment, an inorganic filler such as a silica-based inorganic filler or carbon black, and a material other than the modified conjugated diene polymer of this embodiment, if necessary. Obtained by kneading with a rubbery polymer, silane coupling agent, rubber softener, vulcanizing agent, vulcanization accelerator, vulcanization aid, etc. to form a rubber composition, and then heating and vulcanizing it. be able to.

[Rubber composition]
The rubber composition of this embodiment contains 100 parts by mass of a rubbery polymer containing 10% by mass or more of the modified conjugated diene copolymer of this embodiment, and 5 to 150 parts by mass of a filler.
Further, it is preferable that the filler includes a silica-based inorganic filler.
The rubber composition of this embodiment tends to have better processability when made into a vulcanizate by dispersing a silica-based inorganic filler, and when made into a vulcanizate, it has low hysteresis loss property and wet skid property. It tends to have a better balance with resistance, fracture strength, and wear resistance.
Even when the rubber composition of this embodiment is used for vulcanized rubber applications such as tires, automobile parts such as anti-vibration rubber, and shoes, it is preferable that the rubber composition contains a silica-based inorganic filler.
Examples of fillers include, but are not limited to, silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. These may be used alone or in combination of two or more.

The content of the filler in the rubber composition of this embodiment is 5.0 parts by mass or more and 150 parts by mass or less based on 100 parts by mass of the rubbery polymer containing the modified conjugated diene polymer of this embodiment. It is preferably 10 parts by mass or more and 120 parts by mass or less, more preferably 20 parts by mass or more and 100 parts by mass or less.
The content of the filler is 5.0 parts by mass or more from the viewpoint of exhibiting the effect of adding the filler, and the filler is sufficiently dispersed, and the processability and breaking strength of the rubber composition are practically sufficient. From the viewpoint of this, it is 150 parts by mass or less.

The silica-based inorganic filler is not particularly limited and any known one can be used, but solid particles containing SiO ₂ or Si ₃ Al as a constituent unit are preferred, and SiO ₂ or Si ₃ Al is the main constituent unit. Solid particles contained as a component are more preferred. 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.
Examples of the silica-based inorganic filler include, but are not limited to, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. 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.
In the rubber composition of this embodiment, from the viewpoint of obtaining practically good wear resistance and fracture strength, the nitrogen adsorption specific surface area of the silica-based inorganic filler determined by the BET adsorption method is 100 m ² /g or more and 300 m ² /g. It is preferably 170 m ² /g or more and 250 m ² /g or less. In addition, if necessary, a silica-based inorganic filler with a relatively small specific surface area (for example, a specific surface area of 200 m ² /g or less) and a silica-based filler with a relatively large specific surface area (for example, a specific surface area of 200 m ² /g or more) may be used. (inorganic filler) can be used in combination.
In this embodiment, especially when using a silica-based inorganic filler having a relatively large specific surface area (for example, 200 m ² /g or more), the modified conjugated diene-based polymer improves the dispersibility of silica and is particularly resistant to It is effective in improving wear resistance, and tends to be able to achieve a high balance between good fracture strength and low hysteresis loss.
The content of the silica-based inorganic filler in the rubber composition is 5.0 parts by mass or more and 150 parts by mass, and 20 parts by mass or more, based on 100 parts by mass of the rubbery polymer containing the modified conjugated diene polymer. It is preferably 100 parts by mass or less. The content of the silica-based inorganic filler is 5.0 parts by mass or more from the viewpoint of exhibiting the effect of adding the silica-based inorganic filler, and the silica-based inorganic filler is sufficiently dispersed and the processability of the rubber composition is improved. The amount is 150 parts by mass or less from the viewpoint of achieving practically sufficient breaking strength.

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.
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 or more and 100 parts by mass or less, based on 100 parts by mass of the rubbery polymer containing the modified conjugated diene polymer. More preferably, it is 5.0 parts by mass or more and 50 parts by mass or less. The content of carbon black is preferably 0.5 parts by mass or more from the viewpoint of achieving the performance required for applications such as tires such as dry grip performance and conductivity, and from the viewpoint of dispersibility, it is preferably 100 parts by mass. The following is preferable.

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 the metal hydroxide include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

The rubber composition of this embodiment may also contain a silane coupling agent.
The silane coupling agent has the function of strengthening the interaction between the rubbery polymer and the inorganic filler, and has affinity or bonding groups for the rubbery polymer 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 preferable. Examples of such compounds include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, bis-[2-(triethoxysilyl)-propyl]-tetrasulfide, and bis-[2-(triethoxysilyl)-propyl]-disulfide. silyl)-ethyl]-tetrasulfide.
The content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, based on 100 parts by mass of the above-mentioned inorganic filler. It is more preferably 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 adding the silane coupling agent tends to be more pronounced.

The rubber composition of this embodiment may contain a rubber softener from the viewpoint of improving its processability.
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% by mass or more of all carbons are called paraffinic, and those in which the number of carbon atoms in the naphthene ring accounts for 30% by mass or more and 45% by mass or less of all carbons are called naphthenic and aromatic carbons. Carbons that account for more than 30% by mass of all carbons are called aromatic carbons.
When the modified 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 having an appropriate aromatic compound content. This is preferable because it tends to have good familiarity.
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 rubbery polymer containing the modified conjugated diene polymer. It is 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 rubbery polymer, bleed-out tends to be suppressed and stickiness on the surface of the rubber composition is suppressed.

For methods of mixing modified conjugated diene polymers with other rubber-like polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, rubber softeners, and other additives, see below. Examples include, but are not limited to, melt-kneading methods using common mixing machines such as open rolls, Banbury mixers, kneaders, single-screw extruders, twin-screw extruders, and multi-screw extruders. An example of this method is to heat and remove the solvent after dissolving and mixing.
Among these, melt-kneading methods using rolls, Banbury mixers, kneaders, and extruders are preferred from the viewpoint of productivity and good kneading properties. Furthermore, either a method of kneading the rubbery polymer, 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. The content of the vulcanizing agent 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 rubbery polymer. 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-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based. , thiourea-based, and dithiocarbamate-based vulcanization accelerators. In addition, the vulcanization aid is not limited to the following, but includes, for example, 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 may contain other softeners and fillers other than those mentioned above, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, and lubricants, within a range that does not impair the purpose of this embodiment. You may use various additives such as. As the other softeners, known softeners can be used. Examples of the other fillers include 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.
The rubber composition of this embodiment is not limited to the following, but includes, for example, various tires such as fuel-saving tires, all-season tires, high-performance tires, and studless tires: Tires such as treads, carcass, sidewalls, bead parts, etc. It can be used for various parts. In particular, the rubber composition for tires containing the modified conjugated diene polymer of the present embodiment has an excellent balance between low hysteresis loss and wet skid resistance and wear resistance when made into a vulcanized product. Therefore, it is more suitably used for treads of fuel-saving tires and high-performance tires.

Hereinafter, the present embodiment will be described in 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 were measured by the methods shown below.

[Purification of 1,3-butadiene]
1,3-butadiene used in the polymerization of a modified conjugated diene polymer was purified by the following steps.
(Washing process)
It was operated under conditions of a circulating water amount of 1 m ³ /hr and a renewal (make-up) water amount of 0.1 m ³ /hr.
1,3-butadiene and washing water are mixed using a static mixer (static mixer N60 series manufactured by Noritake Company Limited), and then transferred to a decanter, where the 1,3-butadiene is mixed. The phase and aqueous phase were separated.
The operation was carried out under conditions of a liquid temperature of 30° C. and a decanter pressure of 1.0 MPaG.
The residence time of the 1,3-butadiene phase in the decanter was 30 minutes.
The aqueous phase separated by the decanter is introduced into a 1,3-butadiene removal tank, mixed with steam and heated to 89°C, and at the same time, 1,3-butadiene is removed from the aqueous phase at a total pressure of 0.01 MPaG. separated.

(Oxygen removal process using oxygen scavenger)
Subsequently, using a 10% aqueous solution of Daiclean F-504 (manufactured by Kurita Kogyo) as an oxygen scavenger, the ^1,3 -butadiene after the water washing step and the deoxidized The mixture was mixed with an aqueous solution of an oxygen agent using a static mixer, and liquid-liquid extraction was performed.
Thereafter, the mixture was transferred to a decanter, where a 1,3-butadiene phase and an aqueous phase were separated.
The residence time of the 1,3-butadiene phase in the decanter was 30 minutes. The operation was carried out under conditions of a liquid temperature of 30° C. and a decanter pressure of 1.0 MPaG.

(Polymerization inhibitor removal process)
Furthermore, 10% caustic soda aqueous solution is mixed with the 1,3-butadiene after the above (oxygen removal step using an oxygen scavenger) using a packed column with a Pall ring at a circulating flow rate of 1 m ³ /hr, Liquid-liquid extraction was performed, and the mixture was further transferred to another decanter, where the 1,3-butadiene phase and the aqueous phase were separated.
The residence time of the 1,3-butadiene phase in the other decanter was 60 minutes. In addition, in the polymerization inhibitor removal step, operation was carried out under conditions of a liquid temperature of 30° C. and a decanter pressure of 1.0 MPaG.

(Dehydration tower process)
Mixed hexane was added to the 1,3-butadiene phase separated in the other decanter to give a 1,3-butadiene concentration of 50% by mass, and the mixture was supplied to the dehydration tower.
The azeotropic mixture of 1,3-butadiene and water distilled from the top of the dehydration tower is cooled and condensed, then transferred to a decanter, where it is separated into a 1,3-butadiene phase and an aqueous phase. was separated.
The aqueous phase was removed, and the 1,3-butadiene phase was returned to the inlet of the dehydration tower to carry out the dehydration tower process continuously.
A mixed solution of dehydrated 1,3-butadiene and hexane was taken out from the bottom of the dehydration tower.

(Adsorption process)
The mixed solution of 1,3-butadiene and hexane was passed through a 500L desiccant dryer containing activated alumina (vertical cylindrical tank manufactured by Hitachi, Ltd.) to adsorb trace amounts of residual impurities in the 1,3-butadiene. This was removed to obtain purified 1,3-butadiene.

[Styrene purification]
Styrene used for polymerization of a modified conjugated diene polymer was purified through the following steps.
γ-Alumina molded into a cylindrical shape of 3 mmφ×3 mm was impregnated with an aqueous palladium chloride solution having a concentration of 0.6%, and dried at 100° C. for one day and night. Next, the dried product was subjected to reduction treatment at a temperature of 400° C. for 16 hours under a hydrogen stream to obtain a hydrogenation catalyst having a composition of Pd (0.3%)/γ-Al ₂ O ₃ . Purified styrene was obtained by filling 2000 g of the obtained catalyst into a tubular reactor and circulating styrene for 8 hours while maintaining the temperature of the catalyst at 80°C.

[Purification of normal hexane]
Normal hexane used for polymerization of a modified conjugated diene polymer was purified through the following steps.
Purified normal hexane was obtained by filling a tubular reactor with 2000 g of Molecular Sieve 13-X (Union Showa) and circulating normal hexane at room temperature for 24 hours.

[Raw material purity analysis]
Quantitative analysis of arenes, acetylenes, and amines was performed as impurities in the raw materials.
Arenes and acetylenes were qualitatively and quantitatively determined by gas chromatography.
The column used was Rt-Alumina BOND/MAPD (Shimadzu Corporation).
In addition, amines were extracted using boric acid, quantified by titration, and the total amount of impurities (ppm) was calculated.

[(Physical properties 1) Amount of bound styrene]
Using a modified conjugated diene polymer as a sample, 100 mg of the sample was diluted to 100 mL with chloroform and dissolved to obtain a measurement sample.
The amount of bound styrene (mass %) with respect to 100 mass % of the sample modified conjugated diene polymer was measured based on the absorption amount of the ultraviolet absorption wavelength (near 254 nm) by the phenyl group of styrene. Photometer "UV-2450").

[(Physical properties 2) Microstructure of butadiene moiety (1,2-vinyl bond amount)]
Using a modified conjugated diene polymer as a sample, 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 (Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

[(Physical properties 3) Molecular weight]
Using a modified conjugated diene polymer 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 filler was used. The chromatogram was measured using HLC8020 (product name: HLC8020), and based on the calibration curve obtained using standard polystyrene, weight average molecular weight (Mw), number average molecular weight (Mn), molecular weight distribution (Mw /Mn), the peak top molecular weight (Mp) of the modified conjugated diene polymer, and the proportion of the modified conjugated diene polymer with a molecular weight of 2 million to 5 million.
THF (tetrahydrofuran) 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 sample for measurement was dissolved in 20 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.
The peak top molecular weight (Mp) was determined as follows.
In the GPC curve obtained by measurement, the peak detected as the highest molecular weight component was selected. For the selected peak, the molecular weight corresponding to the maximum value of the peak was calculated and defined as the peak top molecular weight.
Further, the above ratio of molecular weight of 2 million to 5 million was determined as the ratio of the mass of molecular weight of 2 million to 5 million to the total mass of the polymer.

[(Physical properties 4) Polymer Mooney viscosity]
Using an oil extension modified conjugated diene polymer as a measurement sample, Mooney viscosity was measured using a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) in accordance with JIS K6300 and an L-shaped rotor.
The measurement temperature was 100°C.
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 5) Glass transition temperature (Tg)]
An oil-extended modified conjugated diene polymer was used as a measurement sample in accordance with ISO 22768:2006 using a differential scanning calorimeter "DSC3200S" manufactured by Mac Science, under a helium flow of 50 mL/min, at -100 A DSC curve was recorded while increasing the temperature from .degree. C. to 20.degree. C./min, and the peak top (inflection point) of the DSC differential curve was taken as the glass transition temperature. Note that Tg is a value measured for a sample before adding oil.

[(Property 6) Modification rate relative to the total amount of conjugated diene polymer]
Using a modified conjugated diene polymer as a measurement sample, a chromatogram was measured by applying the property of adsorption of the modified basic polymer component to a GPC column using silica gel as a packing material.
Measure the adsorption amount on the silica column from the difference between the chromatogram measured on a polystyrene column and the chromatogram measured on a silica column of the measurement sample solution containing the measurement sample and low molecular weight internal standard polystyrene. Then, the denaturation rate was determined.
Specifically, it is as shown below.
Preparation of sample solution for measurement:
10 mg of the measurement sample and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to prepare a measurement sample solution.
GPC measurement conditions using polystyrene column:
Using Tosoh Corporation's product name "HLC-8320GPC," 10 μL of the measurement sample solution was injected into the device using THF as the eluent, and the column oven temperature was 40°C and the THF flow rate was 0.35 mL/min. , chromatograms were obtained using an RI detector. 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.
GPC measurement conditions using silica column:
Using Tosoh Corporation's product name "HLC-8320GPC," 50 μL of the measurement sample solution was injected into the device using THF as the eluent, and the column oven temperature was 40°C and the THF flow rate was 0.5 mL/min. , chromatograms were obtained using an RI 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 (mass %) 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 (mass%) = [1-(P2×P3)/(P1×P4)]×100
(In the above formula, P1+P2=P3+P4=100.)

[(Property 7) Modification rate of low molecular weight components]
In (Physical Properties 6), for the measurement results of the polystyrene column and silica column, create a molecular weight distribution chart using the calibration curve obtained using standard polystyrene, and then superimpose the two charts obtained. Ta. At this time, the heights of the peak tops of both standard polystyrenes were adjusted to be the same.
The peak top molecular weight in the measurement results of the silica column, that is, the peak top molecular weight of the unmodified conjugated diene polymer is defined as _Mp2 . However, if there are multiple peak tops, the peak top (Mp ₂ ) is the molecular weight of the peak top with the minimum molecular weight, and the height of the peak at this peak top molecular weight (Mp ₂ ) is defined as L2. did.
The height of the molecular weight chart corresponding to Mp ₂ in the measurement results of the polystyrene column was defined as L1. Among the components having a molecular weight corresponding to the above Mp ₂ in the measurement results of the polystyrene column, that is, the component having a molecular weight equal to the above (Mp ₂ ) value among the modified conjugated diene polymers, the low molecular weight component Say.
The modification rate of the low molecular weight component was calculated by (1-L1/L2)×100.

[(Property 8) Contraction factor (g')]
Using a modified conjugated diene polymer as a sample, a chromatogram was measured using a GPC-light scattering measuring device equipped with a viscosity detector that connected three columns with polystyrene gel as a packing material, and the solution viscosity and light were measured. Molecular weight was determined based on scattering method.
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 equipped with a viscosity detector (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 sample solution for measurement, and 200 μL of the sample solution for measurement was injected into a GPC measuring device for measurement.
The intrinsic viscosity and molecular weight of the obtained measurement sample solution are expressed as the constants (K, α) in the relational expression between intrinsic viscosity and molecular weight ([η]=KMα ([η]: intrinsic viscosity, M: molecular weight), logK= -3.883, α=0.771, and the standard intrinsic viscosity created by inputting the range of molecular weight M from 1000 to 20000000 [η] For the relationship between ₀ and molecular weight M, the intrinsic viscosity at each molecular weight M [η] is the relationship between the intrinsic viscosity [η] and the standard intrinsic viscosity [η] ₀ , and [η]/[η] ₀ is calculated for each molecular weight M, and the average value thereof is used as the shrinkage factor (g').
Note that g' is an average value when M is 1 million or more and 2 million or less.

[(Physical properties 9) Silicon content]
The silicon content in the modified conjugated diene polymer was measured using an ICP mass spectrometer (Agilent 7700s manufactured by Agilent Technologies).
Note that an oil-extended modified conjugated diene polymer was used as the measurement sample.

[(Physical properties 10) Nitrogen content]
The nitrogen content in the modified conjugated diene polymer was measured using a trace total nitrogen analyzer (TN-2100H manufactured by Mitsubishi Chemical Analytech).
Note that an oil-extended modified conjugated diene polymer was used as the measurement sample.

[( Reference Example 1) Modified conjugated diene polymer (Sample 1)]
The internal volume is 10L, the ratio of internal height (L) to diameter (D) (L/D) is 4.0,
The polymerization reactor was a tank-type pressure vessel having an inlet at the bottom and an outlet at the top, a stirrer, and a jacket for temperature control.
18.0 g/min of 1,3-butadiene, 9.7 g/min of styrene, from which moisture has been removed in advance.
N-hexane was mixed at 145.3 g/min. The arenes contained in this mixture are 8
ppm, acetylenes were 13 ppm, and amines were 1 ppm. Total impurities were 21 ppm.
In a static mixer installed in the middle of the piping that supplies this mixed solution to the inlet of the reaction group, n-butyllithium for inactivating residual impurities was added at a rate of 0.0864 mmol/min and mixed, and then added to the bottom of the reaction group. Supplied continuously.
Furthermore, 0.0216 g/2,2-bis(2-oxolanyl)propane was added as a polar substance.
n-butyllithium (indicated as "NBL" in the table) was added as a polymerization initiator at a rate of 0.5 min.
The mixture was supplied to the bottom of the polymerization reactor with vigorous mixing using a stirrer at a rate of 207 mmol/min to continue the polymerization reaction continuously. The temperature was controlled so that the temperature of the polymerization solution at the top outlet of the reactor was 70°C.
When the polymerization was sufficiently stabilized, a small amount of the polymer solution before addition of the coupling agent was extracted from the top outlet of the reactor, and after adding an antioxidant (BHT) at 0.2 g per 100 g of polymer, the solvent was removed. It was removed and the molecular weight of each species was measured. Other physical properties are also shown in Table 1.
Next, 0.0% of tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "A" in the table) was added as a modifier to the polymer solution flowing out from the outlet of the reactor.
The polymer solution to which the modifier was added was continuously added at a rate of 259 mmol/min, and was mixed by passing through a static mixer to undergo a modification reaction.
An antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.055 g/min (n-hexane solution) at a rate of 0.2 g per 100 g of polymer to terminate the coupling reaction. , a modified conjugated diene polymer was obtained.
At the same time as antioxidant, add oil (manufactured by JX Nippon Oil & Energy Co., Ltd.) per 100g of polymer.
25 g of JOMO Process NC140) was added continuously and mixed using a static mixer.
After removing the solvent by steam stripping, the modified conjugated diene polymer (sample 1) was prepared.
I got it. Table 1 shows the physical properties of Sample 1.

[(Example 2) Modified conjugated diene polymer (Sample 2)]
The addition rate was 0.130 mm for n-butyllithium for residual impurity inactivation treatment.
ol/min, the polymerization initiator n-butyllithium at 0.346 mmol/min, and the polar substance at 0.346 mmol/min.
0277 g/min, and the modifier was 0.0432 mmol/min. Oil was continuously added in an amount of 10.0 g per 100 g of polymer. Other conditions were the same as in Reference Example 1 to obtain a modified conjugated diene polymer (Sample 2). Table 1 shows the physical properties of Sample 2.

[( Reference Example 3) Modified conjugated diene polymer (Sample 3)]
The addition rates were 0.164 mmol/min for the polymerization initiator, 0.0185 g/min for the polar substance, and 0.0205 mmol/min for the modifier. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 3). Table 1 shows the physical properties of Sample 3.

[(Example 4) Modified conjugated diene polymer (Sample 4)]
The addition rate was 16.6 g/min for butadiene, 11.1 g/min for styrene, 0.268 mmol/min for the polymerization initiator n-butyllithium, 0.0371 g/min for the polar substance, and 0.0 g/min for the modifier. 0335 mmol/min. 10.0 oil per 100g of polymer
It was added continuously so that the amount of Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 4). Table 1 shows the physical properties of Sample 4.

[( Reference Example 5) Modified conjugated diene polymer (Sample 5)]
The respective addition rates were 25.2 g/min for butadiene, 2.5 g/min for styrene, 0.264 mmol/min for the polymerization initiator n-butyllithium, and 0.0213 g/min for the polar substance.
The denaturant was 0.0329 mmol/min. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 5). Table 1 shows the physical properties of Sample 5.

[( Reference Example 6) Modified conjugated diene polymer (Sample 6)]
The addition rate was 0.130 mm for n-butyllithium for residual impurity inactivation treatment.
ol/min, the polymerization initiator n-butyllithium at 0.341 mmol/min, and the polar substance at 0.341 mmol/min.
0274 g/min. The modifier was N,N,N'-tris(3-trimethoxysilylpropyl)-N'-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3- Replaced with propanediamine (abbreviated as “B” in the table) and increased the addition rate to 0.04.
It was set to 26 mmol/min. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 6). Table 1 shows the physical properties of Sample 6.

[( Reference Example 7) Modified conjugated diene polymer (Sample 7)]
The addition rate was 0.130 mm for n-butyllithium for residual impurity inactivation treatment.
ol/min, the polymerization initiator n-butyllithium at 0.341 mmol/min, and the polar substance at 0.341 mmol/min.
0274 g/min. The modifier was changed to tris(3-trimethoxysilylpropyl)amine (abbreviated as "C" in the table), and the addition rate was set to 0.0569 mmol/min. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 7). Table 1 shows the physical properties of Sample 7.

[(Example 8) Modified conjugated diene polymer (Sample 8)]
Oil was added to 100 g of polymer to give a total amount of 10.0 g. Other conditions were the same as in ( Reference Example 7) to obtain a modified conjugated diene polymer (Sample 8).

[( Reference Example 9) Modified conjugated diene polymer (Sample 9)]
The addition rate was 0.130 mm for n-butyllithium for residual impurity inactivation treatment.
ol/min, the polymerization initiator n-butyllithium at 0.341 mmol/min, and the polar substance at 0.341 mmol/min.
0274 g/min. The modifier is bis(3-trimethoxysilylpropyl)-[3-(2
,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine (in the table, "D
”. ) and the addition rate was changed to 0.0569 mmol/min. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 9). The physical properties of Sample 9 are shown in Table 1.

[( Reference Example 10) Modified conjugated diene polymer (Sample 10)]
The addition rate was 0.130 mm for n-butyllithium for residual impurity inactivation treatment.
ol/min, the polymerization initiator n-butyllithium at 0.341 mmol/min, and the polar substance at 0.341 mmol/min.
0274 g/min. The modifier was N-(methoxycarbonylethyl)-N,N-bis(3
-trimethoxysilylpropyl)amine (abbreviated as "E" in the table) and the addition rate was set to 0.
．． 0569 mmol/min. Other conditions were the same as in ( Reference Example 1) to obtain a modified conjugated diene polymer (Sample 10). Table 1 shows the physical properties of sample 10.

[(Example 11) Modified conjugated diene polymer (Sample 11)]
Sample 11 was obtained by kneading Sample 2 and Sample 3 at a mass ratio of 1:2. Table 1 shows the physical properties of Sample 11.

[( Reference Example 12) Modified conjugated diene polymer (Sample 12)]
The internal volume is 10L, the ratio of internal height (L) to diameter (D) (L/D) is 4.0,
Two tank-type pressure vessels having an inlet at the bottom and an outlet at the top, a stirrer, and a jacket for temperature control were connected to form a polymerization reactor.
1,3-butadiene, from which water had been removed in advance, was mixed at 22.3 g/min, styrene at 12.5 g/min, and n-hexane at 214.0 g/min. This mixture contained 8 ppm of arenes, 13 ppm of acetylenes, and 1 ppm of amines. Total impurities were 21 ppm.
In a static mixer installed in the middle of the piping that supplies this mixed solution to the inlet of the reaction group, n-butyllithium for inactivating residual impurities was added at a rate of 0.130 mmol/min.
After mixing, it was continuously fed to the bottom of the reaction group.
Furthermore, 0.0347 g/2,2-bis(2-oxolanyl)propane was added as a polar substance.
minutes, the piperidinolithium prepared in advance as a polymerization initiator (abbreviated as "LA-1" in the table) and n-butyllithium (molar ratio piperidinolithium: n-butyllithium = 0.5 min.
72:0.28, obtained by adjusting the molar ratio of piperidine and n-butyllithium to piperidine:n-butyllithium=0.72:1.00).
(lithium molar ratio)/min to the bottom of the first polymerization reactor, which was vigorously mixed with a stirrer, and the polymerization reaction was continued continuously.
The temperature was controlled so that the temperature of the polymerization solution at the top outlet of the first reactor was 65°C.
By connecting the top of the first reactor and the bottom of the second reactor, it is possible to connect the top of the first reactor to the bottom of the second reactor.
The polymer solution was continuously fed to the bottom of the reactor. The temperature was controlled so that the temperature of the polymer at the top outlet of the second reactor was 70°C.
Next, tris(3-trimethoxysilylpropyl)amine (abbreviated as "C" in the table) was added as a modifier to the polymer solution flowing out from the outlet of the second reactor at a rate of 0.0560 mmol/min. The polymer solution to which the modifier was added was mixed and modified by passing through a static mixer.

[(Comparative Example 1) Modified conjugated diene polymer (Sample 12)]
In the purification of 1,3-butadiene, the residence time of the 1,3-butadiene phase in the decanter in the water washing step was adjusted to 10 minutes. In addition, 1,
The residence time of the 3-butadiene phase was adjusted to 20 minutes.
In addition, a Pd (0.3%)/γ-Al ₂ O ₃ hydrogenation catalyst was obtained in the purification of styrene. A tubular reactor was filled with 2000 g of the obtained catalyst, and while the temperature of the catalyst was maintained at 80° C., the purified styrene was circulated for 4 hours. In the purification of normal hexane, the same purification as in (Example 1) was carried out.
The amount of allenes contained in the mixture of 1,3-butadiene, styrene, and n-hexane is 23pp.
m, acetylenes were 24 ppm, and amines were 10 ppm. Total impurities were 57 ppm. A modified conjugated diene polymer (Sample 12) was obtained in the same manner as in ( Reference Example 1) except that this was used. Table 2 shows the physical properties of Sample 12.

[(Comparative Example 2) Modified conjugated diene polymer (Sample 13)]
The respective addition rates were 0.130 mmol/min for n-butyllithium for inactivating residual impurities, 0.341 mmol/min for n-butyllithium as a polymerization initiator, and 0.0274 g/min for the polar substance. The modifier was changed to tris(3-trimethoxysilylpropyl)amine ("C" in the table), and the addition rate was set to 0.0569 mmol/min. Other conditions were the same as in Comparative Example 1 to obtain a modified conjugated diene polymer (Sample 13). Table 2 shows the physical properties of Sample 13.

[(Comparative Example 3) Modified conjugated diene polymer (Sample 14)]
The respective addition rates were 0.130 mmol/min for n-butyllithium for inactivating residual impurities, 0.250 mmol/min for n-butyllithium as a polymerization initiator, and 0.0192 g/min for the polar substance. The modifier was changed to bis(3-trimethoxysilylpropyl)methylamine ("G" in the table), and the addition rate was set to 0.0853 mmol/min. Other conditions were the same as in Comparative Example 1 to obtain a modified conjugated diene polymer (Sample 14). Table 2 shows the physical properties of Sample 14.

[(Comparative Example 4) Modified conjugated diene polymer (Sample 15)]
The modifier was changed to a coupling agent bis(trimethoxysilyl)ethane ("H" in the table). Other conditions were the same as in Comparative Example 3 to obtain a conjugated diene polymer (Sample 15). Table 2 shows the physical properties of Sample 15.

[( Reference Examples 13, 15, 17-19, 21-22, Example 23, Reference Example 24), and (Comparative Examples 5-8)]
Using the raw material rubbers shown in Tables 1 and 2 (Samples 1, 3, 5-7, 9-16), rubber compositions containing the respective raw material rubbers were obtained according to the formulations shown below.
Modified conjugated diene polymer (Samples 1, 3, 5-7, 9-16): 100 parts by mass (oil removed)
Silica 1 (trade name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m2/g): 50.0 parts by mass Silica 2 (trade name "Zeosil Premium 200MP" manufactured by Rhodia, nitrogen adsorption specific surface area 220 m2/g) : 25.0 parts by mass Carbon black (trade name "SEAST KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.
0 parts by mass Silane coupling agent (trade name "Si75" manufactured by Evonik Degussa, bis(triethoxysilylpropyl) disulfide): 6.0 parts by mass S-RAE oil (trade name "Si75" manufactured by JX Nippon Oil & Energy Corporation) Process NC140”):
37.5 parts by mass Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by mass Anti-aging agent (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine): 2.0 Parts by mass Sulfur: 2.2 parts by mass Vulcanization accelerator 1 (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7
Parts by mass: Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass Total: 234.9 parts by mass The above-mentioned materials were kneaded by the following method to obtain a rubber composition.
Using a closed kneader (inner capacity 0.3 L) equipped with a temperature control device, as the first stage kneading,
Under the conditions of a filling rate of 65% and a rotor rotation speed of 30 to 50 rpm, raw rubber (samples 1 to 16),
Fillers (silica 1, silica 2, carbon black), silane coupling agent, process oil, zinc white, and stearic acid were kneaded.
At this time, each rubber composition (
A formulation) was obtained.

[(Examples 14, 16, 20)]
Using the raw material rubbers shown in Table 1 (Samples 2, 4, and 8), rubber compositions containing the respective raw material rubbers were obtained according to the formulations shown below.
Modified conjugated diene polymer (Samples 2, 4, 8): 100 parts by mass (oil removed)
Silica 1 (trade name "Ultrasil 7000GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area 170 m2/g): 50.0 parts by mass Silica 2 (trade name "Zeosil Premium 200MP" manufactured by Rhodia, nitrogen adsorption specific surface area 220 m2/g) : 25.0 parts by mass Carbon black (trade name "SEAST KH (N339)" manufactured by Tokai Carbon Co., Ltd.): 5.0 parts by mass Silane coupling agent (trade name "Si75" manufactured by Evonik Degussa, bis(triethoxy silylpropyl) disulfide): 6.0 parts by mass S-RAE oil (trade name "Process NC140" manufactured by JX Nippon Oil & Energy Corporation): 10 parts by mass Zinc white: 2.5 parts by mass Stearic acid: 1.0 parts by mass parts 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 -benzothiazyl sulfinamide): 1.7 parts by mass Vulcanization accelerator 2 (diphenylguanidine): 2.0 parts by mass Total: 219.9 parts by mass The above-mentioned materials were kneaded by the following method to obtain a rubber composition. Obtained.
Using a closed kneader (inner capacity 0.3L) equipped with a temperature control device, raw rubber (Samples 2, 4, 8 ), fillers (silica 1, silica 2, carbon black), silane coupling agent, process 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.

[Physical property evaluation method]
(Evaluation 1) Torque rise time During the first stage of kneading in the manufacturing process of the rubber composition, the time required for the torque to reach a constant value after the closed kneader starts kneading is measured. did.
Each measured value was indexed with the result of Comparative Example 6 set as 100.
The smaller the index, the shorter the rising time and the better the moldability.

(Evaluation 2) Sheet processability Using the rubber composition (compound) obtained through the first stage of kneading as described above, a sheet-like composition was processed using an open roll set at 70°C. processed.
The state of the sheet of the obtained sheet composition was visually observed and evaluated on a five-point scale based on the following criteria.
A higher score indicates better sheet processability.
5: Good cohesion during roll work, smooth sheet texture, and no jagged sheet edges.
4: Cohesion is good during roll operation, but the sheet surface is slightly rough and the sheet edges are also slightly jagged.
3: Cohesiveness during rolling operation was a little poor, the sheet surface was a little rough, and the sheet edges were also a little jagged.
2: Cohesiveness during rolling operation was somewhat poor, the sheet surface was rough, and the sheet edges were jagged.
1: Cohesion is poor during roll operation, the sheet surface is rough, and the sheet edges are jagged.

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. The rubber composition before vulcanization and the rubber composition after vulcanization were evaluated. Specifically, it was evaluated by the following method. The evaluation results are shown in Tables 3 and 4.

(Evaluation 3) Compound Mooney viscosity After the second stage of kneading, the rubber composition was used as a sample, using a Mooney viscometer (trade name "VR1132" manufactured by Uejima Seisakusho Co., Ltd.) and an L-shaped rotor in accordance with JIS K6300. Mooney viscosity was measured using
The measurement temperature was 110°C.
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₎ ). The smaller the value, the better the workability.

(Evaluation 4) Viscoelastic Parameters The viscoelastic parameters of the vulcanized rubber composition were measured in torsion mode using a viscoelastic tester "ARES" manufactured by Rheometrics Scientific. Each measurement value was expressed as an index, with the result for the rubber composition of Comparative Example 6 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 value, the better the wet grip property. 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 value, the better the fuel efficiency.
G' measured at 50° C. at a frequency of 10 Hz and a strain of 3% was used as an index of rigidity. The larger the value, the better.

(Evaluation 5) Tensile strength at break, tensile elongation at break Regarding the rubber composition after vulcanization, the tensile strength at break, tensile elongation at break, and M100 (elastic modulus at 100% stretching) were determined according to the tensile test method of JIS K6251. The results of Comparative Example 6 were set as 100 and indexed.

(Evaluation 6) Abrasion resistance The amount of wear of the rubber composition after vulcanization was measured using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) and at a load of 44.4N and 1000 revolutions in accordance with JIS K6264-2. was measured and indexed with the result of Comparative Example 6 set as 100. The larger the index, the better the wear resistance.

As shown in Tables 3 and 4, the rubbers of Reference Example 13, Example 14, Reference Example 15, Example 16, Reference Examples 17-19, Example 20, Reference Examples 21-22, Example 23, and Reference Example 24 It was confirmed that the compositions had a rapid torque increase during kneading, a short torque increase time, and exhibited good processability compared to the rubber compositions of Comparative Examples 5 to 8.
However, for Examples 14, 16, and 20, the modified conjugated diene polymer sample No. The added extender oils Nos. 2, 4, and 8 were the modified conjugated diene polymer sample No. 2 used in Comparative Examples 5 to 8. Although it was expected that the workability would be lower than that of Nos. 13 to 16, it was confirmed that the workability was sufficient for practical use as it showed the same or better workability.
It was also confirmed that when made into a vulcanizate, it has an excellent balance between wet grip properties and low fuel consumption, and is also excellent in wear resistance. However, regarding Reference Example 17, the modified conjugated diene polymer sample No. The glass transition temperature of No. 5 is that of the modified conjugated diene polymer sample No. 5 used in Comparative Examples 5 to 8. Since it is lower than 13 to 16, the result is specialized in wet grip properties.
Furthermore, it was confirmed that it had practically sufficient breaking strength when made into a vulcanized product.
Rigidity also differs depending on the glass transition temperature, so when making comparisons, it is necessary to compare materials with the same glass transition temperature. Further, the higher the molecular weight and the less extender oil contained, the higher the rigidity tends to be.
Comparing Example 14 and Example 20, they have the same breaking strength, but Example 20 has higher rigidity and better balance between breaking strength and rigidity.
Comparing Reference Example 19 and Reference Example 24, it is found that the modified conjugated diene polymer sample No. Since No. 12 contains a nitrogen atom in the polymerization initiator, the nitrogen content is as high as 131 ppm (>70 ppm), so the sheet processability is poor and the rigidity is low.

The modified conjugated diene polymer according to the present invention has industrial applicability in fields such as tire treads, interior and exterior parts of automobiles, anti-vibration rubber, belts, footwear, foams, and various industrial products.

Claims (6)

The weight average molecular weight is 50 × 10 ⁴ or more and 300 × 10 ⁴ or less,
The molecular weight distribution is 1.77 or more and 4.0 or less,
of unmodified conjugated diene polymers in modified conjugated diene polymers obtained by GPC (gel permeation chromatography) using a column packed with a polar substance that can separate modified components containing functional groups from unmodified components. The modification rate of the modified conjugated diene polymer having a molecular weight corresponding to the peak top molecular weight is 40% by mass or more,
The contraction factor (g') is 0.42 or more and less than 0.64,
100 parts by mass of a modified conjugated diene polymer that contains nitrogen and silicon and is a copolymer of a conjugated diene compound and a vinyl aromatic compound ;
20 parts by mass or less of extension oil;
A modified conjugated diene polymer containing. The modified conjugated diene polymer has a contraction factor (g') of 0.60 or more and less than 0.64.
The modified conjugated diene polymer according to claim 1. The modified conjugated diene polymer has a contraction factor (g') of 0.42 or more and less than 0.60.
The modified conjugated diene polymer according to claim 1. The modified conjugated diene polymer is
It has a branched structure,
It has nitrogen at the branch point,
has no nitrogen at the end of the polymer chain that is not attached to the modifier residue;
The modified conjugated diene polymer according to any one of claims 1 to 3. A modified conjugated diene polymer composition comprising 10% by mass or more of the modified conjugated diene polymer according to any one of claims 1 to 4. 100 parts by mass of a rubbery polymer containing 10% by mass or more of the modified conjugated diene polymer according to any one of claims 1 to 4;
5 parts by mass or more and 150 parts by mass or less of filler,
A rubber composition containing.