JP7280115B2 - Method for producing modified conjugated diene polymer mixture - Google Patents

Description

The present invention relates to a method for producing a modified conjugated diene polymer mixture.

In recent years, consideration for the environment has become a social demand, and there is an increasing demand for fuel-saving automobiles. At the same time, high safety is also required.
Specifically, from the viewpoint of fuel efficiency, there is a demand for tire materials that have low resistance to the road surface when the vehicle is running. Materials with hysteresis loss are desired.
From the viewpoint of high safety, materials with excellent wet skid resistance and sufficient breaking properties for practical use are required.

Conventionally, carbon black was often used as a reinforcing filler used in tire treads, but in recent years silica has been widely used from the viewpoint of achieving excellent low hysteresis loss and wet skid resistance. tend to be

It is believed that the introduction of a functional group having an affinity for silica into the rubber molecule suppresses the mobility of the rubber molecule, resulting in excellent low hysteresis loss and wet skid resistance. In accordance with this idea, techniques have been proposed for introducing functional groups having an affinity for silica into rubber molecules.

For example, Patent Document 1 proposes a modified diene polymer obtained by using a polymerization initiator having an amino group. Further, Patent Document 2 proposes a rubber composition containing two different types of modified conjugated diene-based polymers.

JP 2015-131955 A JP 2016-17097 A

However, in recent years, further improvement in low hysteresis loss has been demanded, and a method for efficiently producing a modified conjugated diene-based polymer composition having an excellent balance between wear resistance and workability is also desired.

Therefore, in the present invention, a modified conjugated diene polymer mixture that has excellent low hysteresis loss when made into a vulcanizate containing a silica-based inorganic filler and has an excellent balance between wear resistance and workability, An object of the present invention is to provide an efficient manufacturing method.

The present inventors have made intensive studies to solve the above problems, and found that by mixing modified conjugated diene-based polymers (A) and (B) having different weight average molecular weights (Mw), silica-based inorganic fillers It has excellent low hysteresis loss when made into a vulcanizate containing an agent, and it is possible to produce a modified conjugated diene polymer mixture that has an excellent balance between wear resistance and workability. After the diene polymer is polymerized, it is mixed in a solution state and the solvent is removed. The resulting vulcanizate has excellent low hysteresis loss and is modified with an excellent balance between wear resistance and workability. The inventors have found that a conjugated diene-based polymer mixture can be efficiently produced in a single finishing step, and have completed the present invention.
That is, the present invention is as follows.

[1]
Weight average molecular weight (M
a modified conjugated diene-based polymer (A) having w) of 70×10 ⁴ or more and 300×10 ⁴ or less;
Continuously polymerizing a modified conjugated diene-based polymer (B) having an Mw of 10×10 ⁴ or more and less than 70×10 ⁴ as measured by GPC using one or more reactors,
A polymer solution containing the modified conjugated diene polymer (A) and a polymer solution containing the modified conjugated diene polymer (B) are solution-mixed,
Then, the solvent is removed to obtain a modified conjugated diene polymer mixture (C).
A method for producing a modified conjugated diene-based polymer mixture,
The modified conjugated diene-based polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 or more and 4.5 or less,
Weight average of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B)
The molecular weight difference (ΔMw) is 50×10 ⁴ or more.
A method for producing a modified conjugated diene-based polymer mixture.
[2]
The modified conjugated diene polymer (A
) and the modified conjugated diene-based polymer (B) to a mixing mass ratio ((A)/(B)) of 90/1
The method for producing a modified conjugated diene-based polymer mixture according to [1] above, wherein the mixture is adjusted to 0 to 40/60.
[3]
The method for producing a modified conjugated diene polymer mixture according to [1] or [2] above, wherein Mw of the modified conjugated diene polymer (A) is 100×10 ⁴ or more and 300×10 ⁴ or less.
[4]
The modified conjugated diene according to any one of [1] to [3] above, wherein the modified conjugated diene polymer mixture (C) has a modification rate of 50% by mass or more relative to the total amount of the conjugated diene polymer. A method for producing a system polymer mixture.
[5]
3 of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B)
The method for producing a modified conjugated diene polymer mixture according to any one of the above [1] to [4] , wherein the shrinkage factor (g') by D-GPC is 0.70 or more and 1.0 or less.
[6]
3 of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B)
[1] to the above, wherein the contraction factor (g′) by D-GPC is 0.30 or more and less than 0.70
[4] A method for producing a modified conjugated diene polymer mixture according to any one of [4] .
[7]
The modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) are
The method for producing a modified conjugated diene polymer mixture according to any one of the above [1] to [6] , which has a functional group represented by the following general formula (1) at the polymerization initiation end.

(In the general formula (1), R ¹ and R ² are selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and an aryl group having 6 to 20 carbon atoms. and may be the same or different, wherein R ¹ and R ² may combine to form a ring structure together with the adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total of 4 to 12 carbon atoms.R ¹ and R ² may have an unsaturated bond or a branched structure.)

[8]
The modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) are
Having a functional group represented by the general formula (1) at the polymerization initiation terminal, and at a terminal different from the polymerization initiation terminal having the functional group represented by the general formula (1), an alkoxysilyl group and The method for producing a modified conjugated diene-based polymer mixture according to [7] above, which has an amine-containing functional group.
[9]
The modified conjugated diene-based polymer (B) has a modification rate of 5 with respect to the total amount of the conjugated diene-based polymer.
It is 0% by mass or more, and the modification rate of the component with a molecular weight that is 1/2 of the molecular weight of the peak top in the molecular weight curve, or the molecular weight of the peak top with the smallest molecular weight when there are a plurality of the peak tops, is the modified conjugate The modification rate is 1/2 or more of the total amount of the diene-based polymer, and the nitrogen content in the modified conjugated diene-based polymer (B) is 3 mass ppm or more and 70 mass ppm
The method for producing a modified conjugated diene-based polymer mixture according to any one of the above [1] to [6], wherein the average molecular weight is m or less.

According to the present invention, when a vulcanizate containing a silica-based filler is formed, a modified conjugated diene-based polymer mixture having excellent low hysteresis loss and an excellent balance between wear resistance and workability can be efficiently obtained. It is possible to provide a method for producing a modified conjugated diene-based polymer mixture that can be produced in

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail.
It should be noted that the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. .

[Method for producing modified conjugated diene polymer mixture]
The method for producing the modified conjugated diene-based polymer mixture of the present embodiment includes:
a modified conjugated diene-based polymer (A) having a weight average molecular weight (Mw) of 70×10 ⁴ or more and 300×10 ⁴ or less as measured by GPC (gel permeation chromatography);
Continuously polymerizing a modified conjugated diene-based polymer (B) having an Mw of 10×10 ⁴ or more and less than 70×10 ⁴ as measured by GPC using one or more reactors,
A polymer solution containing the modified conjugated diene polymer (A) and a polymer solution containing the modified conjugated diene polymer (B) are solution-mixed,
After that, the solvent is removed to obtain a modified conjugated diene polymer mixture (C),
The modified conjugated diene polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 or more and 4.5 or less.

(Modified conjugated diene polymer (A) and modified conjugated diene polymer (B))
The modified conjugated diene polymer (A) has a weight average molecular weight (Mw) of 70×10 ⁴ or more and 300×10 ⁴ or less as measured by GPC (gel permeation chromatography). B) has an Mw of 10×10 ⁴ or more and 70×10 ⁴ or less as measured by GPC.
In the method for producing a modified conjugated diene-based polymer mixture of the present embodiment, the two types of modified conjugated diene-based polymers (A) and (B) are continuously polymerized using one or more reactors, respectively. , respectively to obtain a polymer solution.

(Method for producing modified conjugated diene polymer (A) and modified conjugated diene polymer (B))
<Polymerization process>
In the polymerization step of the modified conjugated diene-based polymers (A) and (B), at least the conjugated diene compound is polymerized using an organolithium compound as a polymerization initiator to obtain the conjugated diene-based polymer.
The polymerization process is preferably carried out by a growth reaction based on a living anionic polymerization reaction, whereby a conjugated diene-based polymer having an active terminal can be obtained, and there is a tendency to obtain a modified conjugated diene-based polymer with a high degree of modification. It is in.

In the polymerization step, at least a conjugated diene compound is polymerized, and if necessary, a conjugated diene compound and an aromatic vinyl compound are copolymerized to obtain a conjugated diene copolymer.
The conjugated diene compound is not particularly limited as long as it is a polymerizable monomer, but a conjugated diene compound containing 4 to 12 carbon atoms per molecule is preferred, and a conjugated diene compound containing 4 to 8 carbon atoms is more preferred. is a compound.
Examples of 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 individually by 1 type, and may use 2 or more types together.

The aromatic vinyl compound is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene compound, but a monovinyl aromatic compound is preferred.
Examples of monovinylaromatic compounds include, but are not limited to, styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Among these, styrene is preferable from the viewpoint of industrial availability. These may be used individually by 1 type, and may use 2 or more types together.

The conjugated diene-based polymer obtained in the polymerization step may be a random copolymer or a block copolymer.
In order to convert the conjugated diene-based polymer into a rubber-like polymer, the conjugated diene compound is preferably used in an amount of 40% by mass or more, more preferably 55% by mass or more, based on the total monomers of the conjugated diene-based polymer. more preferred.

Examples of random copolymers include, but are not limited to, random copolymers composed of two or more conjugated diene compounds such as butadiene-isoprene random copolymers, butadiene-styrene random copolymers, and isoprene-styrene random copolymers. Copolymers, butadiene-isoprene-styrene random copolymers, random copolymers composed of a conjugated diene compound and an aromatic vinyl compound can be mentioned.
The composition distribution of each monomer in the copolymer chain is not particularly limited. A copolymer is mentioned. 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.

Examples of block copolymers include, but are not limited to, type 2 block copolymers (diblock) consisting of 2 blocks, type 3 block copolymers (triblock) consisting of 3 blocks, A four-type block copolymer (tetrablock) can be mentioned. A polymer constituting one block may be a polymer composed of one type of monomer or a copolymer composed of two or more types of monomers. For example, a polymer block composed of 1,3-butadiene is represented by "B", a copolymer of 1,3-butadiene and isoprene is represented by "B/I", and a copolymer of 1,3-butadiene and styrene is represented by "B/I". is represented by "B/S", and a polymer block made of styrene is represented by "S", a BB/I2 type block copolymer, a BB/S2 type block copolymer, an S-B2 type block It is represented by a copolymer, BB/SS3 type block copolymer, SBS3 type block copolymer, SBSB4 type block copolymer, and the like.

In the above formula, the boundaries of each block do not necessarily need to be clearly distinguished. Further, 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>
An organic lithium compound can be used as a polymerization initiator in the polymerization step.
Examples of organolithium compounds include, but are not limited to, low molecular compounds, solubilized oligomeric organolithium compounds.
Further, the organolithium compound includes, for example, a compound having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond in the bonding mode of the organic group and the lithium.

The amount of the polymerization initiator to be used is preferably determined according to the molecular weight of the target conjugated diene polymer or modified conjugated diene polymer. The degree of polymerization is related to the amount of the monomer such as the conjugated diene compound used relative to the amount of the polymerization initiator used. That is, it tends to be related to number average molecular weight and/or weight average molecular weight. Therefore, in order to increase the molecular weight, the amount of the polymerization initiator should be decreased, and in order to decrease the molecular weight, the amount of the polymerization initiator should be increased.

The organolithium compound as the polymerization initiator is preferably an alkyllithium compound from the viewpoint of industrial availability and ease of control of the polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal is obtained.
Examples of alkyllithium compounds 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 preferable from the viewpoint of industrial availability and ease of control of the polymerization reaction.

A compound having a nitrogen-lithium bond (hereinafter sometimes referred to as a lithium amide compound) as a polymerization initiator is preferable from the viewpoint of being used as one method for introducing a nitrogen atom into a conjugated diene-based polymer. is an alkyllithium compound having a substituted amino group or a dialkylaminolithium compound.
In this case, a conjugated diene-based polymer having a nitrogen atom composed of an amino group, and a modified conjugated diene-based polymer (A), ( B) is obtained.
Introducing a nitrogen atom into a conjugated diene polymer tends to improve low hysteresis loss and wet skid resistance.

(In the general formula (1), R ¹ and R ² are selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and an aryl group having 6 to 20 carbon atoms. and may be the same or different, wherein R ¹ and R ² may combine to form a ring structure with the adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total of 4 to 12 carbon atoms, and R ¹ and R ² may have an unsaturated bond or a branched structure.).

The alkyllithium compound or dialkylaminolithium compound having the substituted amino group is, for example, a compound represented by the following general formula (2).

(In the general formula (2), R ¹ and R ² are selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms and an aryl group having 6 to 20 carbon atoms. and may be the same or different, wherein R ¹ and R ² may be combined to form a ring structure with the adjacent nitrogen atoms, in which case R ¹ and R ² is a hydrocarbon group having a total carbon number of 4 to 12. R ¹ and R ² may have an unsaturated bond or a branched structure).

Examples of the compound represented by formula (2) include 1-lithiopyrrolidine, 1-lithiopiperidine, 1-lithioazacycloheptane, 1-lithioazacyclooctane, 1-lithioazacycloundecane, lithium diethylamide, and lithium. dibutylamide, lithium dihexylamide, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, lithium ethylbutylamide, lithium ethylhexylamide, lithium butylhexylamide, lithium methylphenylamide, lithium benzylmethylamide, 1-lithio-1,2,3,4-tetrahydropyridine and the like.
In addition, the compound represented by the formula (2) is not limited to these, and analogues thereof are included as long as the above conditions are satisfied.

From the viewpoint of reducing the hysteresis loss of the resin composition using the modified conjugated diene polymer mixture obtained by the present embodiment, the compounds represented by the formula (2) include 1-lithiopyrrolidine, 1-lithiopiperidine, 1-lithioazacycloheptane, lithium dibutylamide, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, 1-lithio-1,2,3,4-tetrahydropyridine, etc. is preferred.
More preferred are 1-lithiopyrrolidine, 1-lithiopiperidine and 1-lithioazacycloheptane, and still more preferred are 1-lithiopiperidine and 1-lithioazacycloheptane.

The lithium amide compound can be synthesized by a known method. For example, it can be obtained by reacting a secondary amine with an organic lithium compound in a hydrocarbon solvent.
Examples of the hydrocarbon solvent include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene, and xylene; Hydrocarbons composed of mixtures thereof and the like are included.
Examples of the secondary amine include, but are not limited to, compounds represented by the following general formula (3).

In the above formula (3), R ¹ and R ² are any selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and an aryl group having 6 to 20 carbon atoms. and may be the same or different. R ¹ and R ² may be combined to form a ring structure with adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total of 4-12 carbon atoms. R ¹ and R ² may have an unsaturated bond or a branched structure.

Examples of the compound represented by formula (3) include pyrrolidine, piperidine, azacycloheptane, azacyclooctane, azacycloundecane, diethylamine, dibutylamine, dihexylamine, 1,3,3-trimethyl-6-azabicyclo [3.2.1] octane, ethylbutylamine, ethylhexylamine, butylhexylamine, methylphenylamine, benzylmethylamine, 1,2,3,4-tetrahydropyridine and the like.
The compounds represented by the above formula (3) are not limited to these, and analogues thereof are included as long as the above conditions are satisfied.

From the viewpoint of reducing the hysteresis loss of the modified conjugated diene-based polymer mixture obtained by the present embodiment, the compounds represented by the formula (3) include pyrrolidine, piperidine, azacycloheptane, dibutylamine, 1,3,3 -trimethyl-6-azabicyclo[3.2.1]octane, 1,2,3,4-tetrahydropyridine are preferred. More preferred are pyrrolidine, piperidine and azacycloheptane. More preferred are piperidine and azacycloheptane.

These organolithium compounds having a substituted amino group are solubilized oligomeric organomonolithium compounds obtained by reacting a small amount of a polymerizable monomer such as 1,3-butadiene, isoprene, or styrene. It can also be used as

The organolithium compound is preferably an alkyllithium compound from the viewpoint of industrial availability and ease of control of the polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal is obtained.
Examples of alkyllithium compounds 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 preferable from the viewpoint of industrial availability and ease of control of the polymerization reaction.

These organolithium compounds may be used singly or in combination of two or more.
Moreover, you may use together with another organometallic compound. Examples of the organometallic compounds include alkaline earth metal compounds, other alkali metal compounds, and other organometallic compounds. Examples of alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds. Also included are compounds of alkaline earth metal alkoxides, sulfonates, carbonates and amides. Organomagnesium compounds include, for example, dibutylmagnesium and ethylbutylmagnesium. Other organometallic compounds include, for example, organoaluminum compounds.

As a polymerization reaction mode in the polymerization step, a continuous polymerization reaction mode is preferred.
In a continuous mode, the polymerization can be carried out using one or more connected reactors.
As the continuous reactor, for example, a tank-type or tubular-type reactor equipped with a stirrer is used. In the continuous system, the monomer, inert solvent, and polymerization initiator are preferably continuously fed to the reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymerization is continuously performed. The combined solution is discharged.

It is preferred that the polymerization step is carried out in an inert solvent. Examples of inert solvents include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific hydrocarbon solvents include, but are not limited to, aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; ; aromatic hydrocarbons such as benzene, toluene and xylene, and hydrocarbons consisting of mixtures thereof.
By treating allenes and acetylenes, which are impurities, with an organometallic compound before being subjected to a polymerization reaction, there is a tendency to obtain a conjugated diene polymer having a high concentration of active terminals, and a high modification rate. This is preferred because it tends to yield the conjugated diene polymers (A) and (B).

A polar compound may be added in the polymerization step. By adding a polar compound, the aromatic vinyl compound can be randomly copolymerized with the conjugated diene compound, and it tends to be used as a vinylating agent for controlling the microstructure of the conjugated diene portion. In addition, it tends to be effective in promoting the polymerization reaction.

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)propane. Ethers such as; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; potassium-tert-amylate, potassium-tert-butylate, sodium-tert-butylate, sodium amine Alkali metal alkoxide compounds such as phosphate; phosphine compounds such as triphenylphosphine;
These polar compounds may be used individually by 1 type, and may use 2 or more types together.

The amount of the polar compound to be used is not particularly limited and can be selected depending on the purpose, etc., but is preferably 0.01 mol or more and 100 mol or less per 1 mol of the polymerization initiator. Such a polar compound (vinylating agent) can be used in an appropriate amount as a modifier for the microstructure of the conjugated diene portion of the resulting polymer, depending on the desired amount of vinyl bonds.
Many polar compounds tend to have an effective randomization effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds at the same time, and can be used as agents for adjusting the distribution of aromatic vinyl compounds and adjusting the amount of styrene blocks. It is in.
As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, as described in JP-A-59-140211, the total amount of styrene and a part of 1,3-butadiene are mixed. A method of starting the polymerization reaction and intermittently adding the remaining 1,3-butadiene during the copolymerization reaction may also be used.

The modified conjugated diene-based polymer (B) constituting the modified conjugated diene-based polymer mixture obtained by the present embodiment has a peak top in the GPC curve, or when there are multiple peak tops, the peak with the lowest molecular weight It is preferable that the modification ratio of the component with a molecular weight that is half the molecular weight of the top molecular weight, ie, the low molecular weight component, is at least half the modification ratio with respect to the total amount of the conjugated diene polymer.
This is because the low-molecular-weight component in the entire polymer is considered to contribute to the processability of the polymer, and the modified conjugated diene polymer (B) is better than the modified conjugated diene polymer (A). When the molecular weight of the modified conjugated diene polymer (B) is small and the modification rate of the low molecular weight component of the modified conjugated diene polymer (B) is within the above range, the workability of the vulcanizate tends to be excellent.
In order to obtain such a modified conjugated diene-based polymer, it is effective to obtain a conjugated diene-based polymer by a polymerization method that causes very little termination of the growth reaction or chain transfer.
Therefore, the monomers and solvents to be introduced into the polymerization reactor must be made to a higher level than before.
Therefore, the total amount of impurities in the monomer components used is preferably 30 ppm or less, and the content concentration (mass) of impurities such as allenes, acetylenes, primary and secondary amines is 20 ppm or less for allenes. is preferably 10 ppm or less, acetylenes are preferably 20 ppm or less, more preferably 10 ppm or less, and the total nitrogen content of primary and secondary amines is 4 ppm or less. is preferred, and 2 ppm or less is more preferred.
Examples of allenes include, but are not limited to, propadiene and 1,2-butadiene. Examples of acetylenes include, but are not limited to, ethylacetylene and vinylacetylene. Examples of primary and secondary amines include, but are not limited to, methylamine and dimethylamine.
In this way, by making the monomer and solvent ultra-highly purified, even in a modified conjugated diene-based polymer having a relatively low nitrogen content of 3 mass ppm or more and 70 mass ppm or less, as described later, low molecular weight components can be obtained. The modification rate can be set to 1/2 or more with respect to the total amount of the conjugated diene polymer.

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

As a polymerization method that causes very little termination of the growth reaction or chain transfer, it is effective to control the polymerization temperature and the monomer conversion rate.
From the viewpoint of terminating the growth reaction or suppressing chain transfer, the lower the polymerization temperature is, the more preferable it is. It is preferably 0° C. or higher, and preferably 80° C. or lower. More preferably, it is 50°C or higher and 75°C or lower. In addition, it is preferable to react the modifier with the conversion rate of the entire monomer of less than 99% by mass. A modifier is added when the monomer remains in the polymerization vessel, and the growing polymer chain is reacted with the modifier before the monomer is completely consumed. It can suppress the formation of coalescence and the occurrence of other side reactions. More preferably the conversion is less than 98% by mass.

The conjugated diene polymer or the modified conjugated diene polymer (A ) and (B) are not particularly limited, but are preferably 40% by mass or more and 100% by mass or less, and more preferably 55% by mass or more and 80% by mass or less. The amount of bound aromatic vinyl in the conjugated diene-based polymer or modified conjugated diene-based polymer (A) and (B) is not particularly limited, but is preferably 0% by mass or more and 60% by mass or less. It is more preferable that it is not less than 45% by mass and not more than 45% by mass.
When the amount of bonded conjugated diene and the amount of bonded aromatic vinyl are within the above ranges, the balance between low hysteresis loss and wet skid resistance, abrasion resistance, and fracture properties tend to be excellent when vulcanized. . Here, the amount of bound aromatic vinyl can be measured by the ultraviolet absorption of the phenyl group, and the amount of bound conjugated diene can also be obtained from this. Specifically, it can be measured according to the method described in the examples below.

In the conjugated diene-based polymer or modified conjugated diene-based polymer, the amount of vinyl bonds in the conjugated diene unit is not particularly limited, but is preferably 10 mol% or more and 75 mol% or less, and 20 mol% or more and 65 mol. % or less. When the vinyl bond content is within the above range, the vulcanizate tends to have a better balance between low hysteresis loss and wet skid resistance, wear resistance, and breaking strength. Here, when the modified diene-based polymer is a copolymer of butadiene and styrene, by Hampton's method (RR Hampton, Analytical Chemistry, 21, 923 (1949)), The vinyl bond content (1,2-bond content) can be determined. Specifically, it can be measured by the method described in Examples described later.

Regarding the microstructure of the modified conjugated diene polymers (A) and (B), each bond amount in the modified conjugated diene polymers (A) and (B) is within the above range, and the modified conjugated diene system To obtain a more excellent vulcanizate due to the balance between low hysteresis loss and wet skid resistance when the glass transition temperature of polymers (A) and (B) is in the range of -45°C or higher and -15°C or lower. tends to be possible. Regarding the glass transition temperature, according to ISO 22768:2006, a DSC curve is recorded while increasing the temperature in a predetermined temperature range, and the peak top (Inflection point) of the DSC differential curve is taken as the glass transition temperature.

When the modified conjugated diene-based polymers (A) and (B) are conjugated diene-aromatic vinyl copolymers, the number of blocks in which 30 or more aromatic vinyl units are chained should be small or absent. Preferably. More specifically, when the copolymer is a butadiene-styrene copolymer, Kolthoff's method (the method described in IM KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)) In a known method of analyzing the amount of polystyrene insoluble in methanol by decomposing the copolymer by % by mass or less, more preferably 3.0% by mass or less.

When the conjugated diene-based polymer before modification of the modified conjugated diene-based polymer (A) and (B) is a conjugated diene-aromatic vinyl copolymer, the proportion of the aromatic vinyl unit present alone is high. preferable. Specifically, when the copolymer is a butadiene-styrene copolymer, the copolymer is decomposed by ozonolysis known as the method of Tanaka et al. (Polymer, 22, 1721 (1981)). , When the styrene chain distribution is analyzed by GPC, the amount of isolated styrene is 40% by mass or more based on the total amount of bound styrene, and the chain styrene structure with 8 or more styrene chains is 5.0% by mass or less. is preferred. In this case, the resulting vulcanized rubber exhibits excellent performance with particularly low hysteresis loss.

The modified conjugated diene polymer (A) constituting the modified conjugated diene polymer mixture obtained by the method for producing a modified conjugated diene polymer mixture of the present embodiment has an Mw of 70×10 ⁴ or more as measured by GPC. 300×10 ⁴ or less, and the modified conjugated diene polymer (B) has an Mw of 10×10 ⁴ or more and less than 70×10 ⁴ .
As a method for controlling each Mw in continuous polymerization in this manner, there is a method of adjusting the polymerization temperature, the amount of monomer added, and the amount of polymerization initiator added in each polymerization step.

<Degeneration step>
After passing through the above-described polymerization step, the conjugated diene-based polymer is subjected to a modification step to obtain modified conjugated diene-based polymers (A) and (B).

In the modification step, the conjugated diene-based polymer obtained by the method described above has a binding group that reacts with the active terminal of the conjugated diene-based polymer, and further has affinity or binding reactivity to the filler. It is reacted with a given modifier having a given 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 having a monofunctional or difunctional bonding group is used as the modifier, a linear terminal-modified diene-based polymer is obtained, and when a polyfunctional compound having a trifunctional or higher bonding group is used, a branched modification is obtained. A diene polymer is obtained.
As the modifier, a monofunctional or polyfunctional compound containing at least one element selected from nitrogen, silicon, tin, phosphorus, oxygen, sulfur and halogen is preferably used. Moreover, an onium structure can be introduced into the modified conjugated diene-based polymer by adding a terminal modifying agent containing an onium forming agent and reacting it. Modifiers containing a plurality of functional groups containing these elements in the molecule or modifiers containing a plurality of functional groups containing these elements can also be used.
As modifiers, 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 terminal of the conjugated diene polymer.

[denaturant]
The modifier will be specifically described below.
Examples of nitrogen-containing compounds include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen group-containing carbonyl compounds, nitrogen group-containing vinyl compounds, and nitrogen group-containing epoxy compounds.
Examples of silicon-containing compounds include, but are not limited to, halogenated silicon compounds, epoxidized silicon compounds, vinylated silicon compounds, alkoxy silicon compounds, and alkoxy silicon compounds containing a nitrogen-containing group.
Examples of tin-containing compounds include, but are not limited to, tin halide compounds, organic tin carboxylate compounds, and the like.
Examples of phosphorus-containing compounds include, but are not limited to, phosphite ester compounds, phosphino compounds, and the like.
Examples of oxygen-containing compounds include, but are not limited to, epoxy compounds, ether compounds, ester compounds, and the like.
Examples of sulfur-containing compounds include, but are not limited to, mercapto group derivatives, thiocarbonyl compounds, isothiocyanates, and the like.
Halogen-containing compounds include, but are not limited to, the aforementioned halogenated silicon compounds, halogenated tin compounds, and the like.

Examples of the onium-generating agent include, but are not limited to, a protected amine compound capable of forming a primary or secondary amine (generating ammonium), a protected phosphine compound capable of forming hydrophosphine ( phosphonium), compounds capable of forming hydroxyl groups and thiols (oxonium and sulfonium), and functional groups for bonding the onium-generating agent and the modified conjugated diene-based polymer are respectively incorporated in the molecule. It is preferable to use a terminal modifying agent having Examples of functional groups for bonding the modified conjugated diene-based polymer include carbonyl groups (ketones, esters, etc.), unsaturated groups such as vinyl groups, epoxy groups, halogenated silicon groups, alkoxy silicon groups, and the like.

The modifier preferably has a nitrogen-containing functional group, and the nitrogen-containing functional group is preferably an amine compound having no active hydrogen. A protected amine compound substituted with a protecting group and an imine compound represented by the general formula -N=C can be mentioned.
Examples of the isocyanate compound of the nitrogen-containing compound that is the modifier include, but are not limited to, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, and polymeric type diphenylmethane diisocyanate. isocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3,5-benzene triisocyanate and the like.
Examples of isocyanuric acid derivatives include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinane-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5- triazinane-2,4,6-trione, 1,3,5-trivinyl-1,3,5-triazinane-2,4,6-trione and the like.
Nitrogen group-containing carbonyl compounds include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2 -methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4' -bis(dimethylamino)benzophenone, methyl-2-pyridyl ketone, methyl-4-pyridyl ketone, propyl-2-pyridyl ketone, di-4-pyridyl ketone, 2-benzoylpyridine, N,N,N',N' -tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, methyl N,N-diethylcarbamate, N,N-diethylacetamide, N,N-dimethyl-N',N'-dimethylamino acetamide, N,N-dimethylpicolinic acid amide, N,N-dimethylisonicotinic acid amide and the like.
Examples of the nitrogen group-containing vinyl compound include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N,N-bistrimethylsilylacrylamide, morpholino acrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis(N,N-dimethylaniline), 4,4'-vinylidenebis(N , N-diethylaniline), 1,1-bis(4-morpholinophenyl)ethylene, 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene and the like.
The nitrogen group-containing epoxy compound includes, but is not limited to, for example, an epoxy group-containing hydrocarbon compound bonded to an amino group, and may further have an epoxy group bonded to an ether group. For example, a compound represented by general formula (4) can be mentioned.

In the formula (4), R is a divalent or higher hydrocarbon group, or a polar group having oxygen such as ether, epoxy and ketone, a polar group having sulfur such as thioether and thioketone, a tertiary amino group, imino It is a divalent or higher valent organic group having at least one polar group selected from nitrogen-containing polar groups such as groups.
The divalent or higher hydrocarbon group is a saturated or unsaturated hydrocarbon group which may be linear, branched or cyclic, and includes an alkylene group, an alkenylene group, a phenylene group and the like. Hydrocarbon groups having 1 to 20 carbon atoms are preferred. For example, methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, p-phenylene, m-, p-xylene, bis(phenylene)-methane and the like.
In formula (4), R ¹ and R ⁴ are hydrocarbon groups having 1 to 10 carbon atoms, and R ¹ and R ⁴ may be the same or different.
R ² and R ⁵ are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R ² and R ⁵ may be the same or different.
R ³ is a hydrocarbon group having 1 to 10 carbon atoms or a structure represented by the following formula (5).
R ¹ , R ² and R ³ may be cyclic structures bonded together.
Moreover, when R ³ is a hydrocarbon group, it may be a cyclic structure in which R is bonded to each other. In the case of the above cyclic structure, the form in which N bonded to R ³ and R are directly bonded may be used.
In formula (4), n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

In formula (5), R ¹ and R ² are defined in the same manner as R ¹ and R ² in formula (4), and R ¹ and R ² may be the same or different.

The nitrogen group-containing epoxy compound used as the modifier preferably has an epoxy group-containing hydrocarbon group, and more preferably has a glycidyl group-containing hydrocarbon group.
Epoxy group-containing hydrocarbon groups bonded to amino groups or ether groups include, for example, glycidylamino groups, diglycidylamino groups and glycididoxy groups. A more preferred molecular structure is an epoxy group-containing compound having a glycidylamino group or diglycidylamino group and a glycididoxy group, respectively, and examples thereof include compounds represented by the following general formula (6).

In formula (6), R is defined in the same manner as R in formula (4) above, and R ⁶ is a hydrocarbon group having 1 to 10 carbon atoms or a structure of formula (7) below.
When R ⁶ is a hydrocarbon group, it may be bonded to R to form a cyclic structure, in which case N and R bonded to R ⁶ may be directly bonded. .
In formula (6), n is an integer of 1 or more, and m is 0 or an integer of 1 or more.

As the nitrogen group-containing epoxy compound used as the modifier, a compound having one or more diglycidylamino groups and one or more glycidoxy groups in the molecule is more preferable.
The nitrogen group-containing epoxy compound used as a modifier is not limited to the following, but examples include N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxy- Cyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidoxy) benzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, N , N,N′,N′-tetraglycidyl-m-xylylenediamine, 4,4-methylene-bis(N,N-diglycidylaniline), 1,4-bis(N,N-diglycidylamino)cyclohexane, N,N,N',N'-tetraglycidyl-p-phenylenediamine, 4,4'-bis(diglycidylamino)benzophenone, 4-(4-glycidylpiperazinyl)-(N,N-diglycidyl)aniline , 2-[2-(N,N-diglycidylamino)ethyl]-1-glycidylpyrrolidine, N,N-diglycidylaniline, 4,4′-diglycidyl-dibenzylmethylamine, N,N-diglycidylaniline , N,N-diglycidylorthotoluidine, N,N-diglycidylaminomethylcyclohexane, and the like. Among these, particularly preferred are N,N-diglycidyl-4-glycidoxyaniline and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane.

Examples of silicon halide compounds as modifiers include, but are not limited to, dibutyldichlorosilane, methyltrichlorosilane, dimethyldichlorosilane, methyldichlorosilane, trimethylchlorosilane, tetrachlorosilane, tris(trimethylsiloxy)chlorosilane, tris( dimethylamino)chlorosilane, hexachlorodisilane, bis(trichlorosilyl)methane, 1,2-bis(trichlorosilyl)ethane, 1,2-bis(methyldichlorosilyl)ethane, 1,4-bis(trichlorosilyl)butane, 1 , 4-bis(methyldichlorosilyl)butane and the like.

Examples of the epoxidized silicon compound as a modifier include, but are not limited to, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, Epoxy modified silicone etc. are mentioned.

Alkoxy silicon compounds as modifiers include, but are not limited to, tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, methoxy-substituted polyorganosiloxane, and the like.

Examples of alkoxy silicon compounds containing nitrogen-containing groups that are modifiers include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3 -morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, 1-[3-( triethoxysilyl)-propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3 -(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 3-dimethylamino-2-(dimethylaminomethyl)propyltrimethoxysilane, bis(3-dimethoxymethylsilylpropyl)-N-methylamine, bis (3-trimethoxysilylpropyl)-N-methylamine, bis(3-triethoxysilylpropyl)methylamine, tris(trimethoxysilyl)amine, tris(3-trimethoxysilylpropyl)amine, N,N,N ',N'-tetra(3-trimethoxysilylpropyl)ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)- 1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxy silylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-phenyl- 1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6 -dioxa-2-silacyclooctane and the like.

As the protected amine compound capable of forming a primary or secondary amine which is a modifier, the compound having an unsaturated bond and a protected amine in the molecule is not limited to the following, for example, 4,4'- vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(t- butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4 '-vinylidenebis[N-methyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(triethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl -N-(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(t-butyldimethylsilyl)aniline], 1-[4-N,N-bis(trimethylsilyl) aminophenyl]-1-[4-N-methyl-N-(trimethylsilyl)aminophenyl]ethylene, 1-[4-N,N-bis(trimethylsilyl)aminophenyl]-1-[4-N,N-dimethyl aminophenyl]ethylene and the like.

Compounds having alkoxysilanes and protected amines in the molecule as protected amine compounds capable of forming primary or secondary amines, which are modifiers, are not limited to the following, for example, N,N-bis ( trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane , N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, 3-(4 -trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethylsilyl-1-imidazolidinyl)propylmethyldiethoxysilane, 3-(3-trimethylsilyl-1-hexahydropyrimidinyl)propyltrimethoxysilane, 2, 2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclo Pentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2 -silacyclopentane, 2,2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2,2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2,2-dimethoxy -1-methyl-1-aza-2-silacyclopentane and the like.

Modifier tin halide compounds include, but are not limited to, tetrachlorotin, tetrabromtin, trichlorobutyltin, trichlorooctyltin, dibromodimethyltin, dichlorodibutyltin, chlorotributyltin, chlorotrioctyltin, chlorotrioctyltin, Phenyltin, 1,2-bis(trichlorostanyl)ethane, 1,2-bis(methyldichlorostanyl)ethane, 1,4-bis(trichlorostanyl)butane, 1,4-bis(methyldichlorostanyl) ) butane and the like.

Examples of organotin carboxylate compounds as modifiers include, but are not limited to, ethyltin tristearate, butyltin trioctanoate, butyltin trisstearate, butyltin trilaurate, and dibutyltin bisoctanoate. be done.

Examples of the phosphite ester compound as the modifier include, but are not limited to, trimethyl phosphite, tributyl phosphite, triphenoxide phosphite, and the like.

Examples of the phosphino compound as a modifier include, but are not limited to, P,P-bis(trimethylsilyl)phosphinopropyltrimethoxysilane, P,P-bis(triethylsilyl)phosphinopropylmethylethoxysilane, and the like. protected phosphino compounds, 3-dimethylphosphinopropyltrimethoxysilane, 3-diphenylphosphinopropyltrimethoxysilane and the like.

Examples of oxygen-containing compounds that are modifiers include, but are not limited to, polyglycidyl ethers such as ethylene glycol diglycidyl ether and glycerin triglycidyl ether, 1,4-diglycidylbenzene, and 1,3,5-triglycidyl. polyepoxy compounds such as benzene, polyepoxidized liquid polybutadiene, epoxidized soybean oil and epoxidized linseed oil; ester compounds such as dimethyl adipate, diethyl adipate, dimethyl terephthalate and diethyl terephthalate; A hydroxyl group is generated at the terminal.

Examples of sulfur-containing compounds that are modifiers include, but are not limited to, protected thiol compounds such as S-trimethylsilylthiopropyltrimethoxysilane, S-triethylsilylthiopropylmethyldiethylsilane, S-methylthiopropyltrimethoxy Sisilane, S-ethylthiopropylmethyldiethoxysisilane, ethyl N,N-diethyldithiocarbamate, phenyl isothiocyanate, phenyl-1,4-diisothiocyanate, hexamethylene diisothiocyanate, butyl isothiocyanate etc.

The modifier is preferably a compound having a silicon-containing functional group, which silicon-containing functional group preferably has an alkoxysilyl group or a silanol group.
The alkoxysilyl group possessed by the modifier reacts, for example, with the active terminal possessed by the conjugated diene-based polymer, dissociating the alkoxylithium, and bonding the terminal of the conjugated diene-based polymer chain to the silicon of the modifier residue. tend to form. A value obtained by subtracting the number of SiORs reduced by the reaction from the total number of SiORs possessed by one modifier molecule is the number of alkoxysilyl groups possessed by the modifier residue. In addition, the azasilacycle group possessed by the modifier forms a >N—Li bond and a bond between the end of the conjugated diene polymer and the silicon of the modifier residue. The >N—Li bond tends to easily become >NH and LiOH by water or the like during finishing. Further, in the modifying agent, unreacted alkoxysilyl groups tend to easily become silanol (Si—OH groups) with water or the like during finishing.
In the modification step, when using a modifying agent having three alkoxy groups per silicon atom, that is, when reacting 3 mol of the active terminal of the conjugated diene-based polymer with 1 mol of the trialkoxysilane group, Although reaction with up to 2 mol of the conjugated diene polymer occurs, 1 mol of alkoxy groups tend to remain unreacted. This can be confirmed from the fact that 1 mol of the conjugated diene polymer remains as an unreacted polymer without reacting. By reacting many alkoxy groups, it tends to be possible to suppress a large change in polymer viscosity due to a condensation reaction during finishing and storage. Preferably, modifiers with one alkoxysilyl group per silicon atom are used.

The modified conjugated diene-based polymer (A) and/or (B) obtained by the modification step described above has a functional group represented by the general formula (1) at the polymerization initiation end, and the general formula ( It is preferable to have a functional group having an alkoxysilyl group and an amine at a terminal different from the polymerization initiation terminal having the functional group represented by 1). This provides the effect of improving the balance between low hysteresis loss and wet skid resistance.
Such modified conjugated diene polymers (A) and (B) can be obtained by appropriately selecting a polymerization initiator and a modifier.
Specifically, styrene and butadiene are randomly polymerized with an aminolithium polymerization initiator, and a modifier having a functional group having an alkoxysilyl group and an amine is added and reacted to obtain an amino group at the polymerization initiation end. , a polymer having functional groups with silyl groups and amines at the terminal ends is obtained.
By having functional groups at both ends of the polymer, the affinity and / or reactivity between the silica compounded in the tire resin composition and both ends of the polymer is increased, and it can be expected that the dispersibility of silica will be increased. .

The reaction temperature in the modification step is preferably the same temperature as the polymerization temperature of the conjugated diene-based polymer, and particularly preferably the temperature without heating after the polymerization. It is more preferably 0° C. or higher and 120° C. or lower, and still more preferably 50° C. or higher and 100° C. or lower.
The reaction time in the modification step is preferably 10 seconds or longer, more preferably 30 seconds or longer.
For mixing the conjugated diene-based polymer and the modifier in the modifying step, any mixing method such as mechanical stirring or stirring using a static mixer may be applied. When the polymerization step is continuous, the modification step is also preferably continuous. The reactor used in the modification step is, for example, a vessel-type vessel equipped with a stirrer or a tubular type. The modifier may be diluted with an inert solvent and fed continuously to the reactor.

A compound represented by the following general formula (8) is preferable as the modifier.

In formula (8), R ¹² to R ¹⁴ each independently represent a single bond or an alkylene group having 1 to 20 carbon atoms, and R ¹⁵ to R ¹⁸ and R ²⁰ each independently represent 1 to 20 carbon atoms. R ¹⁹ and R ²² each independently represent an alkylene group having 1 to 20 carbon atoms, and R ²¹ represents an alkyl group having 1 to 20 carbon atoms or a trialkylsilyl group.
m represents an integer of 1 to 3; p represents 1 or 2;
R ¹² to R ²² , m and p are each independent when a plurality of R 12 to R 22 are present.
i represents an integer of 0-6, j represents an integer of 0-6, k represents an integer of 0-6, and (i+j+k) represents an integer of 1-10.
A is a single bond, 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 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 deactivates the active terminal of the conjugated diene polymer. As the organic group _, an organic is the base. Note that when (i+j+k) is 1, A may be absent.
In the above formula (8), A preferably represents any one of the following general formulas (9) to (12).

In the above formula (9), 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 B ¹ is each independently are doing.

In formula (10), 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 there are a plurality of each.

In formula (11), 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 B ⁴ is each independently there is

In formula (12), 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 B ⁵ is each independently there is

In the above formula (8), when A represents any one of the above formulas (9) to (12), it tends to be possible to obtain a modified conjugated diene polymer with better performance.

As modifiers of formula (8), those having (i+j+k) of 1 to 2 include those overlapping with the modifiers described above and are not limited to the following, for example, 3-dimethoxymethylsilylpropyldimethylamine (monofunctional), 3-trimethoxysilylpropyldimethylamine (bifunctional), bis(3-trimethoxysilylpropyl)methylamine (tetrafunctional), bis(3-dimethoxymethylsilylpropyl)methylamine (bifunctional), (3-Trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ethylamine (tetrafunctional), [3-(2,2-dimethoxy-1-aza -2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)methylamine (tetrafunctional), bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]methylamine (tetrafunctional), bis(3-triethoxysilylpropyl)ethylamine (tetrafunctional), 1-(3-triethoxysilylpropyl)-2,2-diethoxy-1-aza-2-silacyclopentane (tetrafunctional) , 1-(3-dimethoxymethylsilylpropyl)-2,2-dimethoxy-1-aza-2-silacyclopentane (trifunctional), [3-(2,2-diethoxy-1-aza-2-silacyclo pentane)propyl]-(3-diethoxyethylsilylpropyl)methylamine (trifunctional), bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]methylamine (tetrafunctional) , (3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-methylamine (trifunctional).

Hereinafter, as a polyfunctional compound, (i + j + k) is 3 or more, and in the above formula (8), the modifier when A is represented by formula (9) is not limited to the following, for example, tris (3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2 , 2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl ] amine, tris(3-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-silacyclo pentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-sila cyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3 -propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2 ,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine,
Tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl) )-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]- 1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2- trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-( 1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-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-silacyclo pentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propane diamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-triethoxy silylpropyl)-[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-bisaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza-2 -silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]- 1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane , bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila- 2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl) -[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-dimethoxy-1-aza- 2-silacyclopentane)propyl]-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-triethoxysilyl propyl)-1,3-propanediamine,
Tris(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis(3-triethoxysilylpropyl) )-bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza- 2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)-1,3-propanediamine, tetrakis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1 , 3-propanediamine, tris(3-triethoxysilylpropyl)-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, Bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2 -azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-(3-triethoxysilylpropyl)- [3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tris[3-(2,2-diethoxy-1-aza-2 -silacyclopentane)propyl]-[3-(1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-bisaminomethylcyclohexane, tetrakis(3-trimethoxysilylpropyl) )-1,6-hexamethylenediamine, pentakis(3-trimethoxysilylpropyl)-diethylenetriamine.

In the above formula (8), when A is represented by the above formula (10), the modifier is not limited to the following, but for example, tris(3-trimethoxysilylpropyl)-methyl-1,3-propane Diamine, 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), 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 the above formula (8), when A is represented by formula (11), the modifier is not limited to the following, but for example, tetrakis[3-(2,2-dimethoxy-1-aza-2-sila 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, bis(3-trimethoxysilylpropyl)-bis[3-(1-methoxy-2-methyl-1-sila-2-azacyclopentane)propyl]silane .

In the above formula (8), when A is represented by the above formula (12), 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, 3-tris[2-(2,2-dimethoxy-1-aza-2- silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane.

In the above formula (8), when A represents an organic group having an oxygen atom and no active hydrogen, the modifier is not limited to the following, for example, (3-trimethoxysilylpropyl) -[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ether (tetrafunctional), 3,4,5-tris(3-trimethoxysilylpropyl)-cyclohexyl-[3- (2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]ether (octafunctional).

When A in the formula (8) represents an organic group having a phosphorus atom and no active hydrogen, the modifier is not limited to the following, but for example, (3-trimethoxysilylpropyl) phosphate , bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate, bis[3-(2,2-dimethoxy-1-aza- 2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)phosphate, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]phosphate.

In the formula (8), A preferably represents the formula (9) or the formula (10), and k represents 0. As a result, the modified conjugated diene polymer tends to be an easily available modifier, and when the modified conjugated diene polymer is vulcanized, it tends to be more excellent in wear resistance and low hysteresis loss performance.
Examples of such modifiers include, but are not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, Tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclo pentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilyl propyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis[ 3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trismethoxysilylpropyl)-methyl-1,3-propanediamine.

In the formula (8), A more preferably represents formula (9) or formula (10), k represents 0, and in formula (9) or formula (10), a is an integer of 2 to 10 show. The use of such a modifier tends to result in better wear resistance and low hysteresis loss performance when vulcanized.
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, 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 may be mentioned.

The amount of the compound represented by formula (8) added as a modifier can be adjusted so that the number of moles of the polymerization initiator to the number of moles of the modifier is reacted at the desired stoichiometric ratio, and The desired degree of branching is thereby achieved. Specifically, the number of moles of the polymerization initiator is preferably 1.0 times or more, more preferably 2.0 times or more, with respect to the number of moles of the modifier. In this case, in formula (8), the functional group number ((m−1)×i+p×j+k) of the modifier is preferably an integer of 1 to 10, more preferably an integer of 2 to 10.

<Hydrogenation process>
The modified conjugated diene polymers (A) and (B) constituting the modified conjugated diene polymer mixture obtained by the production method of the present embodiment may each have a hydrogenated conjugated diene portion.
A method for hydrogenating the conjugated diene portion is not particularly limited, and a known method can be used.
A suitable hydrogenation method includes a method of hydrogenating by blowing gaseous hydrogen into a polymer solution in the presence of a catalyst.
Examples of catalysts include heterogeneous catalysts such as catalysts in which noble metals are supported on porous inorganic substances; catalysts in which salts such as nickel and cobalt are solubilized and reacted with organic aluminum and the like; and metallocenes such as titanocene are used. Homogeneous catalysts such as catalysts can be mentioned. Among these, a titanocene catalyst is preferable from the viewpoint of being able to select mild hydrogenation conditions. Hydrogenation of aromatic groups can also be carried out by using a noble metal-supported catalyst.

Examples of hydrogenation catalysts include, but are not limited to: (1) supported heterogeneous hydrogenation catalysts in which metals such as Ni, Pt, Pd, and Ru are supported on carbon, silica, alumina, diatomaceous earth, etc.; (2) a so-called Ziegler-type 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 organic aluminum; So-called organometallic complexes such as organometallic compounds such as Zr can be used.
Furthermore, as a hydrogenation catalyst, for example, Also included are known hydrogenation catalysts described in JP-A-2-9041 and JP-A-8-109219. Preferred hydrogenation catalysts include reaction mixtures of titanocene compounds and reducing organometallic compounds.

In the manufacturing process of the modified conjugated diene polymers (A) and (B), after the modification step, a deactivator, a neutralizer, etc. are added to the modified conjugated diene polymer solution, if necessary. good too.
Examples of deactivators include, but are not limited to, water; alcohols such as methanol, ethanol, 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 (mixture of highly branched carboxylic acids with 9 to 11 carbon atoms, mainly 10 carbon atoms); An aqueous solution of an inorganic acid and carbon dioxide gas can be mentioned.

It is preferable to add a rubber stabilizer to the modified conjugated diene polymers (A) and (B) from the viewpoint of preventing gel formation after polymerization and improving the stability during processing.
As the rubber stabilizer, known ones can be used, and examples thereof include, but are not limited to, 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4 Antioxidants such as '-hydroxy-3',5'-di-tert-butylphenol)propinate, 2-methyl-4,6-bis[(octylthio)methyl]phenol and the like can be mentioned.

In order to further improve the processability of the modified conjugated diene-based polymers (A) and (B), an extender oil can be added to the modified conjugated diene-based copolymers, if necessary.
The method for adding the extender oil to the modified conjugated diene polymers (A) and (B) is not limited to the following method, but the extender oil is added to the polymer solution and mixed to obtain an oil-extended copolymer solution. A method of desolvating the resulting product is preferred.
The timing for adding the extender oil is not limited to the timing described below, but examples include after the modification step and before mixing the polymer solution, or after mixing both polymer solutions.
Mixing the extender oil lowers the viscosity of the polymer solution, making it easier to mix the polymer solutions.
Examples of extender oils include aromatic oils, naphthenic oils, paraffin oils and the like. Among these, from the viewpoints of environmental safety, prevention of oil bleed and wet grip properties, aromatic alternative oils containing 3% by mass or less of polycyclic aromatic (PCA) components according to the IP346 method are preferable. Other examples include oils derived from vegetable oils, such as H&R brand names "Vivamax5000" and "Vivamax5100".
Examples of alternative aromatic oils include TDAE (Treatted Distillate Aromatic Extracts) and MES (Mild Extraction Solvate) shown in Kautschuk Gummi Kunststoffe 52 (12) 799 (1999), as well as RAE (Residual Aromatic Extract). tracts).
The amount of the extender oil to be added is not particularly limited, but is preferably 10 parts by mass or more and 60 parts by mass or less, more preferably 20 parts by mass or more and 37.5 parts by mass or less with respect to 100 parts by mass of the modified conjugated diene polymer.

<Mixing process>
In the method for producing the modified conjugated diene-based polymer mixture of the present embodiment, as described above, the modified conjugated diene-based polymer (A) and the modified conjugated diene-based polymer (B) are polymerized through the polymerization step and the modification step. After the combined solution is obtained, these are solution-mixed and the solvent is removed to obtain a modified conjugated diene polymer mixture (C).
Regarding the mixing step, a storage for storing the polymer solution distilled from each reaction vessel downstream of the reaction vessel for the modified conjugated diene polymer (A) and the reaction vessel for the modified conjugated diene polymer (B). A tank is preferably provided. By providing a storage tank for each polymer, it is possible to adjust the flow rate after the modification process and before the mixing process, making it easy to finely adjust the mixing ratio of the polymer solution, and storing it in a tank separate from the reaction tank. can enter.
More preferably, the storage tank has a larger volume than the reaction tank.

Mixing means in this embodiment include, but are not limited to, using a vessel equipped with a rotary stirrer or a tube equipped with a rotary stirrer or a static mixer. From the viewpoint of stirring capacity, it is preferable to use a vessel equipped with a rotary stirrer, and from the viewpoint of production efficiency, it is preferable to use a tube equipped with a rotary stirrer or a static mixer.

Although the temperature in the mixing step is not particularly limited, it is preferably 0° C. or higher and 120° C. or lower, and more preferably 50° C. or higher and 100° C. or lower. This is because the higher the temperature, the lower the viscosity of the polymer solution and the easier it is to mix. In a preferred embodiment, the solution distilled from the top of the polymerization reactor is temporarily stored and then mixed. Heating is not required in the mixing process, but if the storage time is long or the temperature is low, the temperature of the solution can easily drop. You may

The mixing mass ratio of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) in the mixing step is preferably ((A)/(B)) = 90/10 to 40/60. , more preferably 85/15 to 50/50, still more preferably 80/20 to 55/45, still more preferably 75/25 to 60/40.
Within this range, there tends to be an excellent balance between wear resistance and workability when vulcanized.
The above ratio is the mass ratio of the modified conjugated diene-based polymer, and when the concentrations of the polymer solution of the modified conjugated diene-based polymer (A) and the polymer solution of the modified conjugated diene-based polymer (B) are the same may be adopted as the mass ratio of the solution as it is, but these solution concentrations may differ. This is because, when producing a polymer with a small molecular weight, increasing the amount of the polymerization initiator added tends to increase the heat of reaction, so the concentration of the solution may be lowered in order to maintain the polymerization temperature. . In this case, it is preferable to adjust the mixing ratio so as to obtain a preferable polymer mass ratio, taking into account the solution concentration.

A known method such as drying or devolatilization can be used for the solvent removal step. As a method, for example, after separating the solvent by steam stripping or the like, the polymer is separated by filtration, dehydrated and dried to obtain the polymer, concentrated in a flushing tank, further vented extruder, etc. and a method of directly devolatilizing with a drum dryer or the like.

[Physical properties]
(molecular weight)
The weight average molecular weight (Mw) of the modified conjugated diene polymer (A) is 70×10 ⁴ or more and 300×10 ⁴ or less, preferably 70×10 ⁴ or more and 200×10 ⁴ or less, more preferably 100. ×10 ⁴ or more and 180×10 ⁴ or less. It is 70×10 ⁴ or more from the viewpoint of wear resistance when vulcanized, and 300×10 ⁴ from the viewpoint of the balance between wear resistance when vulcanized and workability when vulcanized. or less, preferably 180×10 ⁴ or less.
The weight average molecular weight (Mw) of the modified conjugated diene polymer (B) is 10×10 ⁴ or more and less than 70×10 4 , preferably 15×10 ⁴ or more and 60×10 ⁴ or ^less , more preferably 30. ×10 ⁴ or more and 55×10 ⁴ or less. It is 10×10 ⁴ or more from the viewpoint of wear resistance when vulcanized, and 70×10 from the viewpoint of the balance between wear resistance when vulcanized and workability when vulcanized. It is less than ⁴ , preferably 55×10 ⁴ or less.
In general, the higher the molecular weight, the better the abrasion resistance, but the lower the workability. On the other hand, when the molecular weight is small, the workability is excellent, but the abrasion resistance is poor.
The modified conjugated diene polymer (A) of 70×10 ⁴ or more and 300×10 ^{4 or} less has a large molecular weight and is excellent in abrasion resistance, but tends to be inferior in workability. On the other hand, the modified conjugated diene polymer (B) of 10×10 ⁴ or more and less than 70×10 ⁴ has a small molecular weight and tends to be inferior in abrasion resistance. However, by mixing both, there is a tendency to obtain a modified conjugated diene-based polymer mixture (C) that has respective advantages, ie, an excellent balance between abrasion resistance and workability.
The weight average molecular weight of the modified conjugated diene polymer mixture (C) is 70×10 ⁴ or more and 300×10 ⁴ or less, preferably 85×10 ⁴ or more and 200×10 ⁴ or less, more preferably 100×10. ⁴ or more and 180×10 ⁴ or less. It is 70×10 ⁴ or more from the viewpoint of wear resistance when vulcanized, and 180×10 ⁴ from the viewpoint of the balance between wear resistance when vulcanized and workability when vulcanized. The following are preferred.

ΔMw, which is the difference in weight average molecular weight between the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) of the present embodiment, is preferably 50×10 ⁴ or more, more preferably 60×. It is 10 ⁴ or more, more preferably 70×10 ⁴ or more, and even more preferably 80×10 ⁴ or more.
Within this range, there tends to be an excellent balance between the wear resistance of the vulcanized product and the workability of the vulcanized product.
The higher the molecular weight, the better the abrasion resistance, and the lower the molecular weight, the better the workability.
The larger the difference in weight average molecular weight between the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B), the more wear resistant the modified conjugated diene polymer (A). It means that it becomes a modified conjugated diene-based polymer, and if it is a modified conjugated diene-based polymer (B), it becomes a modified conjugated diene-based polymer that is more specialized in workability.
Therefore, when the two are mixed, they tend to have a large mutual complementary effect.
The weight average molecular weights (Mw) of the modified conjugated diene polymers (A) and (B) can be controlled by adjusting the polymerization temperature, amount of monomer added, and amount of polymerization initiator added in each polymerization step. can.
When the polymerization temperature in the polymerization step is raised, the polymerization reaction rate tends to be faster and a polymer with a large weight average molecular weight can be obtained. However, if the polymerization temperature is too high, the polymer terminals are deactivated by heat, and the modification reaction does not proceed, and the weight average molecular weight of the modified conjugated diene polymer tends to be difficult to increase.
When the amount of monomer added in the polymerization step is increased, the amount of monomer polymerized per molecule of the polymerization initiator increases, so the weight average molecular weight tends to increase.
When the amount of the polymerization initiator added in the polymerization step is increased, the amount of the monomer polymerized per molecule of the polymerization initiator decreases, so the weight average molecular weight tends to decrease.
From this, the weight average molecular weight difference (ΔMw) between the modified conjugated diene polymer (A) and (B) can be can be controlled within the above numerical range by appropriately adjusting the conditions in .

(Molecular weight distribution)
The modified conjugated diene polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 or more and 4.5 or less. It is preferably 1.85 or more and 4.0 or less, more preferably 1.90 or more and 3.50 or less.
Within this range, there tends to be an excellent balance between the wear resistance of the vulcanized product and the workability of the vulcanized product.
The molecular weight distribution of the modified conjugated diene polymer mixture (C) can be adjusted to the above values by adjusting the molecular weight difference, molecular weight distribution, and composition ratio between the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B). Range can be controlled.

(denaturation rate)
The modification rate of the modified conjugated diene-based polymer mixture (C) is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass with respect to the total amount of the conjugated diene-based polymer. % or more, and more preferably 80 mass % or more. When the modification rate is within the above range, the processability of the vulcanizate tends to be excellent, and the vulcanizate tends to have an excellent balance between low hysteresis loss and wet skid resistance.
The modification rate of the modified conjugated diene-based polymer (A) and the modified conjugated diene-based polymer (B) is preferably 50% by mass, preferably 65% by mass or more, relative to the total amount of the conjugated diene-based polymer. More preferably, it is still more preferably 80% by mass or more.
Within this range, the workability of the vulcanizate is excellent, and the vulcanizate tends to have a good balance between low hysteresis loss and wet skid resistance. It is preferable that both the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) have a high modification rate.
Comparing a modified conjugated diene polymer with a large molecular weight and a modified conjugated diene polymer with a small molecular weight, the modified conjugated diene polymer with a small molecular weight exhibits low hysteresis loss and wet skid when vulcanized. It tends to be well balanced with resistance. Therefore, when only one of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) has a high modification rate, the modified conjugated diene polymer (B) preferably has a high modification rate.
The modification rate of the modified conjugated diene polymer mixture (C) and the modified conjugated diene polymers (A) and (B) is determined by, for example, the purity of the monomers and solvents used for polymerization, the amount of modifier added, the temperature in the modification step, etc., it is possible to control within the numerical range described above.

(contraction factor)
The shrinkage factor (g') measured by GPC with a viscosity detector-light scattering method measurement (hereinafter also simply referred to as "GPC with a viscosity detector-light scattering method measurement" or "3D-GPC measurement") is It is an index of the number of branches of the modified conjugated diene polymer. For example, as the shrinkage factor (g′) decreases, the number of branches of the modified conjugated diene-based polymer (for example, the number of branches of the star polymer (also referred to as “the arm number of the star polymer”)) increases. There is a tendency.
When comparing modified conjugated diene-based polymers having the same molecular weight, the shrinkage factor (g′) decreases as the number of branches in the modified conjugated diene-based polymer increases. It can be used as an index of degree.
Contraction factor (g') is measured using 3D-GPC measurements.
Constants (K, α) in the relational expression between intrinsic viscosity and molecular weight ([η] = KMα ([η]: intrinsic viscosity, M: molecular weight) are logK = -3.883, α = 0.771, standard A graph of the relationship between intrinsic viscosity [η] ₀ and molecular weight M is created.
With respect to this standard intrinsic viscosity [η] ₀ , the intrinsic viscosity [η] at each molecular weight M of the sample obtained by 3D-GPC measurement is expressed as the relationship between the intrinsic viscosity [η] and the standard intrinsic viscosity [η] ₀ [ η]/[η] ₀ is calculated for each molecular weight M, and the average value is taken as the shrinkage factor (g').
More specifically, it can be measured by the method described in Examples below.

In the modified conjugated diene-based polymer (A) and/or the modified conjugated diene-based polymer (B), the shrinkage factor (g') measured using 3D-GPC is 0.70 or more and 1.0 or less. is mentioned as a preferred form.
When the shrinkage factor (g') of the modified conjugated diene polymer (A) and/or (B) is within the above range, the strength at high temperatures tends to be excellent.
The shrinkage factor (g') is an index of the branched structure of the modified conjugated diene-based copolymer. It tends to be a modified conjugated diene polymer having 4 or less branches in one polymer molecule. In such a case, the shrinkage factor (g') is more preferably 0.73 or more and 0.99 or less, more preferably 0.75 or more and 0.98 or less.
In order to obtain a modified conjugated diene copolymer having a shrinkage factor (g') within the above range, for example, a modifier having 4 or less reaction points with living active terminals is added to the total number of moles of the polymerization initiator. On the other hand, it is effective to obtain a modified conjugated diene-based copolymer having 4 or less branches by adding 1/4 or more of the molar number.
If the branched structure is the same, the strength at high temperatures tends to be superior as the molecular weight increases. It is preferably 0 or less.

Further, the modified conjugated diene-based polymer (A) and/or (B) more preferably has a shrinkage factor (g') measured using 3D-GPC of 0.30 or more and less than 0.70.
Such a modified conjugated diene-based polymer has a lower viscosity in a composition to which a filler is added, and has better workability.
The shrinkage factor (g') is an index of the branched structure of the modified conjugated diene-based copolymer. The diene polymer tends to be a modified conjugated diene polymer having 5 or more branches per molecule.
In order to obtain a modified conjugated diene copolymer having a shrinkage factor (g′) within the above range, for example, a modifier having 5 or more reaction points with the living active terminal is added to the total number of moles of the polymerization initiator. On the other hand, it is effective to obtain a modified conjugated diene copolymer having 5 or more branches by adding 1/5 or less of the number of moles.
The modified conjugated diene-based polymer having a shrinkage factor (g′) of 0.30 or more and less than 0.64 has 6 or more branches, and the modified conjugated diene-based polymer of 0.30 or more and less than 0.59 is They tend to have 8 or more branches. Such modified conjugated diene-based polymers result in even lower viscosities in filled compositions and even better processability.
Processability tends to be better when the molecular weight is smaller if the branched structure is the same. It is preferably less than, more preferably 0.30 or more and less than 0.64, and even more preferably 0.30 or more and less than 0.59.

The shrinkage factor (g′) measured using 3D-GPC of the modified conjugated diene polymer (A) is 0.70 or more and 1.0 or less, and the 3D-GPC of the modified conjugated diene polymer (B) is used. It is preferable that the shrinkage factor (g') measured by Within such a range, there is a tendency to obtain a modified conjugated diene-based polymer mixture having an excellent balance between high-temperature strength and workability.

(Nitrogen content)
In the production method of the present embodiment, the modified conjugated diene polymer (B) preferably has a nitrogen content of 3 ppm by mass or more and 70 ppm by mass or less.
When it is 3 mass ppm or more, the effect of improving the balance between low hysteresis loss and wet skid resistance when made into a vulcanizate is obtained, and when it is 70 mass ppm or less, silica is dispersed when it is made into a compound. It is possible to obtain the effect of suppressing the decrease in rigidity due to excessive tightening.
More preferably, it is 6 mass ppm or more and 60 mass ppm or less, and still more preferably 10 mass ppm to 50 mass ppm.
The nitrogen content can be controlled within the above numerical range 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 end.

[Polymer composition]
The modified conjugated diene-based polymer mixture obtained by the method for producing a modified conjugated diene-based polymer mixture of the present embodiment can be combined with other materials to form a polymer composition.
The polymer composition preferably contains 10% by mass or more of the modified conjugated diene polymer mixture (C).
The polymer composition may contain a polymer other than the modified conjugated diene polymer mixture (C).
Polymers other than the modified conjugated diene polymer mixture (C) include rubber-like polymers having structures other than those of the modified conjugated diene-based polymers (A) and (B) (hereinafter referred to as “other rubber-like polymers coalescence"), or resinous polymers.
Examples of other rubber-like polymers include, but are not limited to, conjugated diene-based polymers or hydrogenated products thereof, random copolymers of conjugated diene-based 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. Other specific rubber-like polymers include, but are not limited to, the following: Examples include butadiene block copolymers or hydrogenated products thereof, styrene-based elastomers such as styrene-isoprene block copolymers or hydrogenated products thereof, acrylonitrile-butadiene rubbers or hydrogenated products thereof.
Examples of the non-diene polymer include, but are not limited to the following, olefins such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber. elastomer, butyl rubber, brominated butyl rubber, acrylic rubber, fluorine rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber are mentioned.
Examples of the natural rubber include, but are not limited to, smoked sheet RSS Nos. 3 to 5, SMR, and epoxidized natural rubber.

As a method for mixing the modified conjugated diene polymer mixture (C) with a polymer other than the modified conjugated diene polymers (A) and (B) (referred to as another polymer), a modified conjugated diene polymer There are various methods such as a method of mixing a solution of the mixture (C) and a solution of another polymer, a method of mechanically mixing the modified conjugated diene polymer mixture (C) and another polymer, and the like.
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 "other rubber-like polymer", the weight average molecular weight thereof is preferably 2,000 or more and 2,000,000 or less from the viewpoint of the balance between performance and processability. It is more preferably 5,000 or more and 1,500,000 or less. Low-molecular-weight rubber-like polymers, so-called liquid rubbers, can also be used. These other rubber-like polymers may be used singly or in combination of two or more.

When the polymer composition containing the modified conjugated diene polymer mixture (C) contains another rubbery polymer, the content ratio of the modified conjugated diene polymer mixture (C) to the other rubbery polymer ( The mass ratio) is preferably 10/90 or more and 100/0 or less, more preferably 20/80 or more and 90/10 or less, as (modified conjugated diene polymer mixture (C)/other rubber-like polymer). /50 or more and 80/20 or less is more preferable.
Therefore, the polymer composition preferably contains 10 parts by mass or more and 100 parts by mass or less of the modified conjugated diene polymer mixture (C) with respect to the total amount (100 parts by mass) of the polymer composition, and more It is preferably contained in an amount of 20 to 90 parts by mass, more preferably 50 to 80 parts by mass.
When the content ratio of (modified conjugated diene-based polymer mixture (C)/other rubber-like polymer) is within the above range, the vulcanized product has a good balance between low hysteresis loss and wet skid resistance. Excellent, wear resistance and breaking strength are also satisfied.

The modified conjugated diene polymer mixture (C) is preferably used as a vulcanizate. Examples of the vulcanizates include tires, hoses, shoe soles, anti-vibration rubbers, automobile parts, and anti-vibration rubbers, as well as resin-reinforced rubbers such as impact-resistant polystyrene and ABS resins. In particular, the modified conjugated diene-based polymer is suitably used in the composition of tread rubber for tires. The vulcanizate is, for example, the modified conjugated diene polymer mixture (C), optionally silica-based inorganic fillers, inorganic fillers such as carbon black, modified conjugated diene polymer mixtures other than (C) It is obtained by kneading with a rubber-like polymer, a silane coupling agent, a rubber softening agent, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, etc. to form a rubber composition, and then vulcanizing by heating. be able to.

[Rubber composition]
The modified conjugated diene-based polymer mixture obtained by the production method of the present embodiment can be used in rubber compositions.
The rubber composition preferably contains 100 parts by mass of a rubber-like polymer containing 10% by mass or more of the modified conjugated diene copolymer mixture (C) and 5 to 150 parts by mass of a filler.
Moreover, the filler preferably contains a silica-based inorganic filler.
By dispersing the silica-based inorganic filler, the rubber composition tends to be more excellent in processability when vulcanized, and when vulcanized, it has low hysteresis loss and wet skid resistance. balance, breaking strength and wear resistance.
Also when the rubber composition is used for vulcanized rubber applications such as automobile parts such as tires and anti-vibration rubbers and shoes, it is preferable to contain 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 individually by 1 type, and may use 2 or more types together.

The content of the filler in the rubber composition is 5.0 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the rubber-like polymer containing the modified conjugated diene polymer mixture (C). It is preferably 10 parts by mass or more and 120 parts by mass or less, and even more preferably 20 parts by mass or more and 100 parts by mass or less.
The content of the filler is preferably 5.0 parts by mass or more from the viewpoint of expressing the effect of adding the filler. From the viewpoint of sufficient content, it is preferably 150 parts by mass or less.

_{The silica-based inorganic filler is not particularly limited, and known ones can be used. Solid particles containing SiO 2 or Si 3 Al as} a _structural unit are preferable, and Solid particles included as a component are more preferred. Here, the main component means a component contained in the silica-based inorganic filler in an amount of 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more.
Examples of silica-based inorganic fillers include, but are not limited to, inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. In addition, a silica-based inorganic filler having a hydrophobized surface, and a mixture of a silica-based inorganic filler and a non-silica-based inorganic filler may also be used. 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 preferable from the viewpoint of an excellent balance between the effect of improving fracture properties and wet skid resistance.
In the rubber composition, 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 or less, from the viewpoint of obtaining practically good abrasion resistance and fracture characteristics. 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 less than 200 m ² /g) and a silica-based filler with a relatively large specific surface area (for example, 200 m ² /g or more) and inorganic fillers can be used in combination.
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 effective in improving wear resistance. It tends to be highly effective and provides a good balance between good fracture properties 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 with respect to 100 parts by mass of the rubber-like polymer containing the modified conjugated diene polymer mixture (C). is preferred, and more preferably 20 parts by mass or more and 100 parts by mass or less. The content of the silica-based inorganic filler is preferably 5.0 parts by mass or more from the viewpoint of expressing the effect of adding the inorganic filler, sufficiently dispersing the inorganic filler, and improving the processability and From the viewpoint of making the mechanical strength practically sufficient, it is preferably 150 parts by mass or less.

Examples of carbon black include, but are not limited to, each class of carbon black such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon black having a nitrogen adsorption specific surface area of 50 m ² /g or more and a dibutyl phthalate (DBP) oil absorption of 80 mL/100 g or less is preferable.
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 with respect to 100 parts by mass of the rubber-like polymer containing the modified conjugated diene polymer mixture (C). It is more preferably 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 expressing the performance required for tires such as dry grip performance and conductivity, and 100 parts by mass from the viewpoint of dispersibility. It is preferable to:

A metal oxide is a solid particle whose structural unit is a main component of the chemical formula MxOy (M represents a metal atom, and x and y each independently represents an integer of 1 to 6.) . Examples of metal oxides include, but are not limited to, alumina, titanium oxide, magnesium oxide, and zinc oxide.
Examples of metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.

The rubber composition may contain a silane coupling agent.
The silane coupling agent has the function of enhancing the interaction between the rubber-like polymer and the inorganic filler, and provides groups with affinity or bonding to the rubber-like polymer and the silica-based inorganic filler, respectively. A compound having a sulfur-bonding portion and an alkoxysilyl group or silanol group portion in one molecule is preferred. Examples of such compounds include bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, bis-[2-(triethoxy 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 with respect to 100 parts by mass of the inorganic filler. 0 parts by mass or more and 15 parts by mass or less is more preferable. 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 may contain a rubber softener from the viewpoint of improving its processability.
Suitable rubber softeners are mineral oils or liquid or low molecular weight synthetic softeners. Mineral oil-based rubber softeners called process oils or extender oils used to soften, expand, and improve the processability of rubber are mixtures of aromatic rings, naphthenic rings, and paraffin chains. , Paraffinic chain carbon atoms occupying 50 mass% or more of the total carbon are called paraffinic, naphthenic ring carbon atoms occupying 30 mass% or more and 45 mass% or less of the total carbon are naphthenic, aromatic carbon Those whose number accounts for more than 30% by mass of the total carbon are called aromatic systems.
When the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) contained in the modified conjugated diene polymer mixture (C) are copolymers of a conjugated diene compound and a vinyl aromatic compound, As the softening agent for rubber to be used, one having an appropriate content of aromatic compounds tends to have good compatibility with the copolymer, and thus it is preferable.
The content of the softener for rubber is preferably 0 parts by mass or more and 100 parts by mass or less, and 10 parts by mass or more and 90 parts by mass with respect to 100 parts by mass of the rubber-like polymer containing the modified conjugated diene polymer mixture (C). Part or less is more preferable, and 30 to 90 parts by mass is even more preferable. When the content of the softening agent for rubber is 100 parts by mass or less with respect to 100 parts by mass of the rubber-like polymer, bleeding out is suppressed and stickiness of the surface of the rubber composition tends to be suppressed.

About the method of mixing the modified conjugated diene-based polymer mixture (C) with other rubber-like polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, additives such as rubber softeners Is not limited to the following, for example, an open roll, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, a melt-kneading method using a general kneading machine such as a multi-screw extruder, each A method of removing the solvent by heating after dissolving and mixing the components may be used.
Among these, a melt-kneading method using rolls, a Banbury mixer, a kneader, or an extruder is preferable from the viewpoint of productivity and good kneading properties. In addition, both a method of kneading the rubber-like polymer and other fillers, a silane coupling agent, and additives at once, and a method of mixing them in multiple batches can be applied.

The rubber composition may be a vulcanized composition vulcanized with a vulcanizing agent. Examples of vulcanizing agents 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 with respect to 100 parts by mass of the rubber-like polymer. As the vulcanization method, a conventionally known method can be applied, and the vulcanization temperature is preferably 120° C. or higher and 200° C. or lower, more preferably 140° C. or higher and 180° C. or lower.
For vulcanization, a vulcanization accelerator may be used as necessary. As the vulcanization accelerator, conventionally known materials can be used, and are not limited to the following; , thiourea-based and dithiocarbamate-based vulcanization accelerators. Examples of vulcanizing aids include, but are not limited to, 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 with respect to 100 parts by mass of the rubber component.
The rubber composition may contain softeners and fillers other than those mentioned above, heat stabilizers, antistatic agents, weather stabilizers, anti-aging agents, colorants, Various additives such as lubricants may be used. As other softening agents, known softening agents can be used. Other fillers include, for example, calcium carbonate, magnesium carbonate, aluminum sulfate and barium sulfate. As the heat stabilizer, antistatic agent, weather stabilizer, anti-aging agent, colorant, and lubricant, known materials can be used.

〔tire〕
The rubber composition is suitably used as a rubber composition for tires.
The rubber composition is not limited to the following, for example, various tires such as fuel-saving tires, all-season tires, high-performance tires, studless tires: tread, carcass, sidewall, bead portion, etc. is available. In particular, the rubber composition for tires containing the modified conjugated diene polymer mixture (C) is excellent in balance between low hysteresis loss and wet skid resistance and wear resistance when vulcanized. Therefore, it is more preferably used for treads of fuel-saving tires and high-performance tires.

EXAMPLES Hereinafter, the present embodiment will be described in more detail with specific examples and comparative examples, but the present embodiment is not limited by the following examples.
Materials used in Examples and Comparative Examples and evaluation methods for various properties are shown below.

[Purification of 1,3-butadiene]
1,3-butadiene used for polymerization of the 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 (makeup) 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 Co., Ltd.), then transferred to a decanter, and 1,3-butadiene is mixed in the decanter. The phases and aqueous phase were separated.
The operation was performed under the 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 water phase separated by the decanter is introduced into the 1,3-butadiene removal tank, mixed with steam and heated to 89° C. At the same time, the total pressure is set to 0.01 MPaG to remove 1,3-butadiene from the water phase. separated.

(Oxygen removal step with oxygen scavenger)
Subsequently, a 10% aqueous solution of Daiclean F-504 (manufactured by Kurita Water Industries) was used as a deoxidizing agent, and the circulation flow rate was 1 m ³ /hr. An aqueous solution of an oxygen agent was mixed using a static mixer to perform liquid-liquid extraction.
After that, it was moved to a decanter, and the 1,3-butadiene phase and the aqueous phase were separated in the decanter.
The residence time of the 1,3-butadiene phase in the decanter was 30 minutes. The operation was performed under the conditions of a liquid temperature of 30° C. and a decanter pressure of 1.0 MPaG.

(Polymerization inhibitor removal step)
Subsequently, a 10% caustic soda aqueous solution is mixed with 1,3-butadiene after the above (oxygen removal step with a deoxidizing agent) at a circulation flow rate of 1 m ³ /hr using a packed column with pole rings, Liquid-liquid extraction was carried out and transferred to another decanter, where the 1,3-butadiene phase and 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 removing step, the operation was performed under the 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 by another decanter in the above (polymerization inhibitor removal step) to adjust the 1,3-butadiene concentration to 50% by mass, and the mixture was supplied to the dehydration tower.
After cooling and condensing the azeotropic mixture of 1,3-butadiene and water distilled from the top (top) of the dehydration tower, it is transferred to a decanter, where the 1,3-butadiene phase and the water phase are separated. separated.
The aqueous phase was removed, and the 1,3-butadiene phase was returned to the inlet of the dehydration tower to continuously carry out the dehydration tower process.
A mixture of dehydrated 1,3-butadiene and hexane was taken out from the bottom of the dehydration tower.

(adsorption process)
After the above (dehydration step), the mixed liquid of 1,3-butadiene and hexane is passed through a 500 L desiccant dryer containing activated alumina (a vertical cylindrical tank manufactured by Hitachi, Ltd.), and was removed by adsorption to obtain purified 1,3-butadiene.

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

[Purification of normal hexane]
Normal hexane used for polymerization of the modified conjugated diene polymer was purified by the following steps.
A tubular reactor was filled with 2000 g of molecular sieve 13-X (Union Showa) and circulated at room temperature for 24 hours to obtain purified normal hexane.

[Purity analysis of raw materials (calculation of total impurities)]
Allenes, acetylenes, and amines were quantitatively analyzed as impurities in the raw material.
Allenes and acetylenes were qualitatively and quantitatively determined by gas chromatography.
The column used was Rt-Alumina BOND/MAPD (Shimadzu Corporation).
Amines were extracted with boric acid and quantified by a titration method to calculate the total amount (ppm) of impurities.

[(Physical property 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 (% by mass) with respect to 100% by mass of the modified conjugated diene-based polymer as a sample was measured from the absorption amount of the ultraviolet absorption wavelength (around 254 nm) by the phenyl group of styrene (spectrophotometer manufactured by Shimadzu Corporation "UV-2450").

[(Physical property 2) Microstructure of butadiene portion (1,2-vinyl bond content)]
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 wavenumber is measured by Hampton's method (RR Hampton, Analytical Chemistry 21, 923 (1949)). The microstructure of the butadiene portion, that is, the amount of 1,2-vinyl bonds (mol %) was determined according to the formula of (Fourier transform infrared spectrophotometer "FT-IR230" manufactured by JASCO Corporation).

[(Physical property 3) molecular weight]
Using a modified conjugated diene-based polymer as a sample, a GPC measuring device (manufactured by Tosoh Corporation, trade name "HLC-8320GPC") in which three columns with polystyrene gel as a filler are connected, an RI detector (Tosoh Measure the chromatogram using the company's product name "HLC8020"), and based on the calibration curve obtained using standard polystyrene, the weight average molecular weight (Mw ₁ ), the number average molecular weight (Mn ₁ ), and the molecular weight A distribution (Mw ₁ /Mn ₁ ) was obtained.
THF (tetrahydrofuran) was used as the eluent.
As for the columns, three columns manufactured by Tosoh under the trade name of "TSKgel SuperMultiporeHZ-H" were connected, and a guard column manufactured by Tosoh under the trade name of "TSKguardcolumn SuperMP (HZ)-H" was connected to the preceding column.
10 mg of a sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 10 μL of the measurement solution was injected into a GPC measurement device and measured under the conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL/min.

[(Physical property 4) Modification rate with respect to total amount of conjugated diene polymer]
Using the modified conjugated diene-based polymer as a measurement sample, a chromatogram was measured by applying the characteristics of adsorption of the modified basic polymer component to a GPC column filled with silica-based gel.
The amount of adsorption to the silica column is measured from the difference between the chromatogram of the measurement sample solution containing the measurement sample and low molecular weight internal standard polystyrene measured with a polystyrene column and the chromatogram measured with a silica column. and the denaturation rate was calculated.
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 a polystyrene column:
Using Tosoh Corporation's trade name "HLC-8320GPC", using THF as an eluent, injecting 10 μL of the sample solution for measurement into the device, column oven temperature 40 ° C., THF flow rate 0.35 mL / min. , chromatograms were obtained using an RI detector. As the columns, three columns of Tosoh's product name "TSKgel Super MultiporeHZ-H" were connected, and a Tosoh company's product name "TSKguardcolumn SuperMP(HZ)-H" was connected as a guard column in front of them.
GPC measurement conditions using a silica-based column:
Using Tosoh's trade name "HLC-8320GPC", using THF as an eluent, injecting 50 μL of the sample solution for measurement into the device, column oven temperature 40 ° C., THF flow rate 0.5 mL / min. , chromatograms were obtained using an RI detector. The columns are used by connecting the product names "Zorbax PSM-1000S", "PSM-300S", and "PSM-60S". connected and used.
How to calculate the denaturation rate:
The total peak area of the chromatogram using a polystyrene column is 100, the peak area of the sample is P1, the peak area of standard polystyrene is P2, and the total peak area of the chromatogram using a silica column is 100, and the sample Using the peak area of P3 as P3 and the peak area of standard polystyrene as P4, the modification rate (% by mass) was obtained from the following formula.
Modification rate (mass%) = [1-(P2 × P3) / (P1 × P4)] × 100
(In the above formula, P1+P2=P3+P4=100.)

[(Physical property 5) Modification rate of low molecular weight component]
According to the measurement of (physical property 3), using a GPC measuring device (trade name "HLC-8320GPC" manufactured by Tosoh Corporation) in which three columns with polystyrene gel as a filler are connected, an RI detector (Tosoh Corporation (trade name "HLC8020" manufactured by Sanken Co., Ltd.), and based on a calibration curve obtained using standard polystyrene, the weight average molecular weight (Mw ₂ ) and number average molecular weight ( Mn ₂ ), molecular weight distribution (Mw ₂ /Mn ₂ ), and peak top molecular weight (Mp ₂ ) of the modified conjugated diene polymer were measured.
The peak top molecular weight (Mp ₂ ) is the peak top molecular weight in the molecular weight curve, or when there are a plurality of peak tops, the molecular weight of the peak top with the smallest molecular weight, and this peak top molecular weight (Mp ₂ ) L1 is the height of the chart at a molecular weight that is 1/2 of .
L2 was defined as the height at the molecular weight that is 1/2 the peak top molecular weight (Mp ₂ ) of the chart measured according to the measurement of (physical property 3) using a silica column.
A component with a molecular weight that is half the molecular weight at the peak top is defined as a low molecular weight component.
The denaturation rate of low molecular weight components was calculated by 1-L1/L2.

[Degree of denaturation of low molecular weight component]
The degree of modification of the low-molecular-weight component was calculated by dividing the (physical property 5) modification rate (FL) of the low-molecular-weight component by the (physical property 4) modification rate (FT) relative to the total amount of the conjugated diene-based polymer.
Degree of denaturation of low molecular weight component = (FL/FT) x 100

[(Physical Property 6) Shrinkage Factor (g′)]
Using a modified conjugated diene polymer as a sample, a chromatogram is measured using a GPC-light scattering measurement device with a viscosity detector in which three columns filled with polystyrene gel are connected to measure the solution viscosity and light. Molecular weight was determined based on the scattering method.
A mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mL of triethylamine with 1 L of tetrahydrofuran) was used as an eluent.
As the columns, a guard column (trade name: "TSKguardcolumn HHR-H" manufactured by Tosoh Corporation) and columns: trade names (trade names: "TSKgel G6000HHR", "TSKgel G5000HHR", and "TSKgel G4000HHR" manufactured by Tosoh Corporation) were connected and used.
A GPC-light scattering measurement device with a viscosity detector (trade name “Viscotek TDAmax” manufactured by Malvern) was used under 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 measurement device for measurement.
The intrinsic viscosity and molecular weight of the obtained sample solution for measurement 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), log K = -3.883, α = 0.771, the standard intrinsic viscosity [η] created by inputting the range of molecular weight M from 1000 to 20000000 For the relationship between ₀ and molecular weight M, the intrinsic viscosity at each molecular weight M Assuming that [η] is the relation of intrinsic viscosity [η] to standard intrinsic viscosity [η] ₀ , [η]/[η] ₀ was calculated for each molecular weight M, and the average value was taken as the shrinkage factor (g').
Note that g' is an average value when M is 1 million or more and 2 million or less.

[Production of modified conjugated diene polymer]
(Modified conjugated diene polymer A1)
A tank reactor with an internal volume of 10 L, a ratio (L/D) of internal height (L) to diameter (D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected to form a polymerization reactor.
22.2 g/min of 1,3-butadiene, 12.0 g/min of styrene, and 210 g/min of n-hexane, from which moisture had been removed in advance, were mixed. This mixture contained 9 ppm of allenes, 15 ppm of acetylenes, and 2 ppm of amines. Total impurities were 26 ppm.
In a static mixer provided in the middle of the pipe that supplies this mixed solution to the inlet of the first reaction group, n-butyllithium for deactivation treatment of residual impurities is added at 0.0800 mmol/min, mixed, and then one group is mixed. It was continuously fed to the bottom of the second reactor.
Further, 2,2-bis(2-oxolanyl)propane as a polar substance was added at a rate of 0.0120 g/min, and previously prepared piperidinolithium as a polymerization initiator (abbreviated as “LA-1” in the table). and n-butyllithium (molar ratio piperidinolithium:n-butyllithium = 0.75:0.25, piperidine and n-butyllithium, molar ratio piperidine:n-butyllithium = 0.75:1.00 ) at a rate of 0.0800 mmol (molar ratio of lithium)/min to the bottom of the first polymerization reactor, which is vigorously mixed with a stirrer, and the polymerization reaction is continuously continued. let me
The temperature was controlled so that the temperature of the polymer 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, the polymer solution was continuously supplied from the top of the first reactor to the bottom of the second reactor. The temperature was controlled so that the temperature of the polymer at the top outlet of the second reactor was 70°C.
Next, when the polymerization is sufficiently stabilized, the polymer solution flowing out from the outlet of the second reactor is
An antioxidant (BHT) was continuously added at a rate of 0.055 g/min (n-hexane solution) to 0.2 g per 100 g of polymer to terminate the polymerization reaction.
At the same time as the antioxidant, 37.5 g of extender oil (JOMO Process NC140 manufactured by JX Nikko Nisseki Energy Co., Ltd.) was continuously added to 100 g of the polymer and mixed with a static mixer.
The modified conjugated diene polymer solution mixed with the extender oil was subjected to steam stripping to remove the solvent to obtain a modified conjugated diene polymer A1. Various measurements were performed and the results are shown in Table 1.
Furthermore, the obtained polymer solution was sent to a tank-type pressure vessel having an internal volume of 100 L.

(Modified conjugated diene polymer A2)
A tank reactor with an internal volume of 10 L, a ratio (L/D) of internal height (L) to diameter (D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected to form a polymerization reactor.
22.2 g/min of 1,3-butadiene, 12.0 g/min of styrene, and 210 g/min of n-hexane, from which moisture had been removed in advance, were mixed. This mixture contained 9 ppm of allenes, 15 ppm of acetylenes, and 2 ppm of amines. Total impurities were 26 ppm.
In a static mixer provided in the middle of the pipe that supplies this mixed solution to the inlet of the first reaction group, n-butyllithium for deactivation treatment of residual impurities is added at 0.0800 mmol/min, mixed, and then one group is mixed. It was fed continuously to the bottom of the second reactor.
Furthermore, 2,2-bis(2-oxolanyl)propane as a polar substance was added at a rate of 0.0157 g/min, and previously prepared piperidinolithium as a polymerization initiator (abbreviated as “LA-1” in the table). and n-butyllithium (molar ratio piperidinolithium:n-butyllithium = 0.75:0.25, piperidine and n-butyllithium, molar ratio piperidine:n-butyllithium = 0.75:1.00 ) at a rate of 0.144 mmol (molar ratio of lithium)/min to the bottom of the first polymerization reactor, which is vigorously mixed with a stirrer, and the polymerization reaction is continuously continued. let me
The temperature was controlled so that the temperature of the polymer 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, the polymer solution was continuously supplied from the top of the first reactor to the bottom of the second reactor. The temperature was controlled so that the temperature of the polymer at the top outlet of the second reactor was 70°C.
Next, when the polymerization was sufficiently stabilized, bis(3-trimethoxysilylpropyl)methylamine (abbreviated as "A" in the table) was added as a modifier to the polymer solution flowing out from the outlet of the second reactor. was added continuously at a rate of 0.0360 mmol/min, and the polymer solution to which the modifier was added was mixed and modified by passing through a static mixer.
Antioxidant (BHT) was continuously added to the modified polymer solution at 0.055 g/min (n-hexane solution) so as to be 0.2 g per 100 g of polymer to complete the modification reaction.
At the same time as the antioxidant, 37.5 g of extender oil (JOMO Process NC140 manufactured by JX Nikko Nisseki Energy Co., Ltd.) was continuously added to 100 g of the polymer and mixed with a static mixer.
The modified conjugated diene polymer solution mixed with the extender oil was subjected to steam stripping to remove the solvent to obtain a modified conjugated diene polymer A2. Various measurements were performed and the results are shown in Table 1.
Further, the resulting modified conjugated diene polymer solution was sent to a tank-type pressure vessel having an internal volume of 100 L.

(Modified conjugated diene-based polymer A3, modified conjugated diene-based polymers B1 to B3)
The production method is the same as for the modified conjugated diene-based polymer A2, and the addition amount of the polymerization initiator, the addition amount of the polar substance, the type of modifier, and the addition amount of the modifier are as shown in Tables 1 and 2 below. A modified conjugated diene polymer A3 and modified conjugated diene polymers B1 to B3 were obtained.
In Tables 1 and 2, modifier "B" means N,N,N'-tris(3-trimethoxysilylpropyl)-N'-[3-(2,2-dimethoxy-1-aza-2- silacyclopentane)propyl]-1,3-propanediamine.

(Modified conjugated diene polymer A4)
A tank reactor with an internal volume of 10 L, a ratio (L/D) of internal height (L) to diameter (D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with a stirrer. Two tank-type pressure vessels having a stirrer and a jacket for temperature control were connected to form a polymerization reactor.
18.0 g/min of 1,3-butadiene, 9.7 g/min of styrene, and 145 g/min of n-hexane, all of which had previously been dehydrated, were mixed. This mixture contained 9 ppm of allenes, 15 ppm of acetylenes, and 2 ppm of amines. Total impurities were 26 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 is added at 0.0648 mmol/min, mixed, and then added to the bottom of the reaction group. fed continuously.
Further, 2,2-bis(2-oxolanyl)propane as a polar substance at a rate of 0.0216 g/min, and n-butyllithium (abbreviated as “NBL” in the table) as a polymerization initiator at 0.0864 mmol/min. minutes at a rate of 10 minutes to the bottom of the polymerization reactor, which is vigorously mixed with an agitator to continue the polymerization reaction continuously. The temperature was controlled so that the temperature of the polymer solution at the reactor top outlet was 75°C.
When the polymerization was sufficiently stabilized, 3-(4-methyl-1-piperazino)propyltriethoxysilane (abbreviated as "C" in the table) was added as a modifier to the polymer solution flowing out from the outlet of the reactor. The polymer solution added continuously at a rate of 0.0432 mmol/min was passed through a static mixer and mixed to undergo a modification reaction.
An antioxidant (BHT) was continuously added to the modified polymer solution at a rate of 0.2 g per 100 g of polymer at 0.055 g/min (n-hexane solution) to terminate the coupling reaction. . Simultaneously with the antioxidant, 37.5 g of oil (JOMO Process NC140 manufactured by JX Nippon Oil & Energy Corporation) was continuously added to 100 g of the polymer, and mixed with a static mixer.
The solvent was removed from the modified conjugated diene polymer solution mixed with the extender oil by steam stripping to obtain a modified conjugated diene polymer A4. Various measurements were performed and the results are shown in Table 1.
Further, the resulting modified conjugated diene polymer solution was sent to a tank-type pressure vessel having an internal volume of 100 L.

(Modified conjugated diene polymers A5 to A11, modified conjugated diene polymers B4 to B10)
The production method is the same as for modified conjugated diene polymer A4, and the amount of polymerization initiator added, the amount of polar substance added, the type of modifier, and the amount of modifier added are adjusted as shown in Tables 1 and 2 below. Then, modified conjugated diene polymers A5 to A11 and modified conjugated diene polymers B4 to B10 were obtained.
Various measurements were performed and the results are shown in Tables 1 and 2.
Further, the resulting modified conjugated diene-based polymer solution was sent to tank-type pressure vessels each having an internal volume of 100 L.
In Tables 1 and 2, modifier "D" is tetraglycidyl-1,3-bisaminomethylcyclohexane.
Modifier “E” is tris(3-trimethoxysilylpropyl)amine.

In the table, when two numerical values are described for the polymerization temperature, the former indicates the polymerization temperature for the first unit and the latter indicates the polymerization temperature for the second unit.
The denaturant is shown below.
A: bis (3-trimethoxysilylpropyl) methylamine B: N,N,N'-tris (3-trimethoxysilylpropyl) -N'-[3-(2,2-dimethoxy-1-aza-2 -silacyclopentane)propyl]-1,3-propanediamine C: 3-(4-methyl-1-piperazino)propyltriethoxysilane D: tetraglycidyl-1,3-bisaminomethylcyclohexane E: tris (3- trimethoxysilylpropyl)amine

(Example 1: Modified conjugated diene polymer mixture C1)
The polymer solution of the modified conjugated diene-based polymer A6 and the polymer solution of the modified conjugated diene-based polymer B1, which were produced by the method described above and were sent to the tank-type pressure vessel, were combined with the modified conjugated diene-based polymer A6 and the modified The mass ratio of the conjugated diene polymer B1 was (A6):(B1)=70:30, and the two were combined in the pipe. After merging, they were stirred and mixed with a rotary stirrer.
Next, the solvent was removed by steam stripping to obtain a modified conjugated diene polymer mixture C1.
Various measurements were performed and the results are shown in Table 3.

(Examples 2-13, Reference Example 14, Example 15, Reference Examples 16-17, Examples 18-21 : Modified Conjugated Diene Polymer Mixtures C2-C21)
The production method is the same as the modified conjugated diene polymer mixture C1, changing the combination of the modified conjugated diene polymer A and the modified conjugated diene polymer B to be used, and modifying in the modified conjugated diene polymer mixture C The content of the conjugated diene polymer A was varied as shown in Tables 3 and 4 to obtain modified conjugated diene polymer mixtures C2 to C21.
Various measurements were performed and the results are shown in Tables 3 and 4.

[Examples 22-34, Reference Example 35, Example 36, Reference Examples 37-38, Examples 39-42 , Comparative Examples 1-21]
The samples shown in Tables 1 to 4 above (modified conjugated diene polymer mixtures C1 to C21, modified conjugated diene polymers A1 to A11, modified conjugated diene polymers B1 to B10) were used as raw material rubbers according to the formulation shown below. , to obtain a modified conjugated diene polymer composition containing each raw material rubber.
・Sample: 100 parts by mass ・Silica (manufactured by Evonik Degussa, trade name “Ultrasil 7000GR”, nitrogen adsorption specific surface area: 175 m / g): 75 parts by mass ・Silane coupling agent (manufactured by Evonik Degussa, trade name “Si75” (Tetraethoxysilylpropyl disulfide): 6 parts by mass Process oil (manufactured by JX Nippon Oil & Energy Corporation, trade name “NC140”): 42
Parts by mass Carbon black (manufactured by Tokai Carbon Co., Ltd., trade name "Siest KH (N339)", iodine adsorption amount 90 g / kg, CTAB specific surface area 95 m ² / g): 5 parts by mass Zinc white (manufactured by Mitsui Kinzoku Mining Co., Ltd., Product name “Zinchua No. 1”): 2.5 parts by mass Stearic acid: 1.0 parts by mass Wax: (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., product name “Sannok”, yellowish white granules, freezing point 6
5 ° C. or higher, specific gravity 0.93,: 1.5 parts by mass Anti-aging agent (N-isopropyl-N'-phenyl-p-phenylenediamine): 2.0
Parts by mass Sulfur: 2.2 parts by mass Vulcanization accelerator (N-cyclohexyl-2-benzothiazylsulfinamide): 1.7 parts by mass Vulcanization accelerator (diphenylguanidine): 2.0 parts by mass

The above materials were kneaded by the following method to obtain an unvulcanized rubber composition and a vulcanized rubber sheet.

Using a kneader (contents 0.5 L) equipped with a temperature control device, as the first stage of kneading, the modified conjugated diene polymer (modified SBR1), silica The system inorganic filler (silica), silane coupling agent and process oil were kneaded for 4 minutes. At this time, the temperature of the kneader was controlled, and the discharge temperature (mixture) was 155 to 160° C. to obtain a modified conjugated diene polymer composition.

Next, as the second step of kneading, after the mixture obtained above was cooled to room temperature, carbon black, zinc white, stearic acid, wax and antioxidant were added and kneaded for 3 minutes with the kneader. In this case as well, the discharge temperature (formulation) was adjusted to 155-160° C. by controlling the temperature of the mixer. Immediately after discharging the compound from the kneader, the compound was passed through a 10-inch φ open roll six times to prepare a sheet-like unvulcanized rubber composition, which was cooled and evaluated for processability.

Furthermore, after heating the unvulcanized composition to 70°C for 30 minutes using an oven, sulfur and a vulcanization accelerator were added using a 10-inch φ open roll set at 70°C as the third stage of kneading. and kneaded to obtain a composition. After that, the remainder of the composition was vulcanized and molded with a vulcanizing press at 160° C. for 20 minutes to obtain a vulcanized product. After vulcanization, physical properties of the rubber composition were measured. The physical property measurement results are shown in Tables 5 to 10 below.

[Method for measuring physical properties]
(Compound Mooney viscosity)
After kneading in the second stage, the rubber composition was used as a sample, and a Mooney viscometer (trade name "VR1132" manufactured by Ueshima Seisakusho Co., Ltd.) was used to measure the Mooney viscosity using an L-shaped rotor in accordance with JIS K6300. .
The measurement temperature was 100°C.
First, after preheating the sample for 1 minute at the test temperature, the rotor was rotated at 2 rpm, and the torque after 4 minutes was measured to obtain the Mooney viscosity (ML ₍₁₊₄₎ ).
The result of Comparative Example 6 was indexed as 100 and used as an index of workability. A larger index indicates better workability.

(viscoelastic parameter)
A viscoelasticity tester "ARES" manufactured by Rheometrics Scientific Co., Ltd. was used to measure the viscoelasticity parameters of the vulcanized rubber composition in a torsion mode. Each measured value was indexed by setting the result for the rubber composition of Comparative Example 6 to 100.
Tan δ measured at 0° C. with a frequency of 10 Hz and a strain of 1% was used as an index of wet grip properties. A higher value indicates better wet grip. In addition, the reciprocal of tan δ measured at 50° C. with a frequency of 10 Hz and a strain of 3% was used as an index of fuel economy. A larger value indicates better fuel economy.

(Tensile breaking strength)
The rubber composition after vulcanization was measured for tensile strength at break according to the tensile test method of JIS K6251, and indexed with the result of Comparative Example 6 as 100.

(wear resistance)
For the rubber composition after vulcanization, using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho), in accordance with JIS K6264-2, load 44.4N, 1000 rotations to measure the amount of wear, Comparative Example 6 The result was indexed as 100. A larger index indicates better wear resistance.

From the evaluation results of the compositions of Comparative Examples 1 to 21 using only the modified conjugated diene polymers A1 to A11 and the modified conjugated diene polymers B1 to B10, respectively, the modified conjugated diene polymer A and the modified conjugated diene By considering the mass fraction of the system polymer B, the expected value of the evaluation results of the compositions of Examples 22 to 32 using the modified conjugated diene polymer mixtures C1 to C21 of Examples 1 to 21 was calculated. .
For example, in the case of the modified conjugated diene polymer mixture C1, the mass ratio of the modified conjugated diene polymer A and the modified conjugated diene polymer B is 70:30. expected value)=(evaluation result of modified conjugated diene polymer A)×(70/100)+(evaluation result of modified conjugated diene polymer B)×(30/100).
In the same way, the predicted values calculated for each were compared with the actual results.
Expected values and measurement results are shown in Tables 5 to 8 below.
In Tables 5 to 8, the numerical value on the left side of each example column is the actual measured value, and the numerical value on the right side is the predicted value calculated from the mass fraction.

The measured values of Comparative Examples 1 to 21 are shown in Tables 9 and 10 below.

As shown in Tables 5 to 10, the compositions using the modified conjugated diene polymer mixtures of Examples 1 to 13, Reference Examples 14, 15, Reference Examples 16 to 17, and Examples 18 to 21 were It was found that although the abrasion resistance was inferior to that of the compositions using the corresponding modified conjugated diene polymers A1 to A11 alone, the workability was excellent.
In addition, the actual measurement result is superior to the estimated evaluation value of the composition of the modified conjugated diene polymer mixture C considering the mass fractions of the modified conjugated diene polymer A and the modified conjugated diene polymer B. It was found to have a good balance between low hysteresis loss, wet skid resistance, wear resistance and workability. Similarly, it was found that the processability is superior to the composition using the corresponding modified conjugated diene polymers B1 to B10 alone, but the abrasion resistance is also superior.
In addition, the actual measurement result is more than the expected evaluation value of the composition using the modified conjugated diene polymer mixture C considering the mass fractions of the modified conjugated diene polymer A and the modified conjugated diene polymer B. It was found to have a good balance between low hysteresis loss, wet skid resistance, wear resistance and workability. Moreover, it was confirmed that it has practically sufficient tensile strength.
Furthermore, in order to obtain a modified conjugated diene polymer mixture C, instead of mixing the modified conjugated diene polymer A and the modified conjugated diene polymer B from which the solvent has been removed after polymerization, Mixing the modified conjugated diene-based polymer A and the modified conjugated diene-based polymer B in a solution state,
Finished. As a result, the modified conjugated diene-based polymer C can be obtained in one finishing step, although two finishing steps were originally required, and the production process is made more efficient.

The method for producing a modified conjugated diene-based polymer mixture according to the present invention is industrially applicable in fields such as tire treads, automobile interior and exterior parts, anti-vibration rubber, belts, footwear, foams, and various industrial products. have a nature.

Claims (9)

Weight average molecular weight (M
a modified conjugated diene-based polymer (A) having w) of 70×10 ⁴ or more and 300×10 ⁴ or less;
Continuously polymerizing a modified conjugated diene-based polymer (B) having an Mw of 10×10 ⁴ or more and less than 70×10 ⁴ as measured by GPC using one or more reactors,
A polymer solution containing the modified conjugated diene polymer (A) and a polymer solution containing the modified conjugated diene polymer (B) are solution-mixed,
Then, the solvent is removed to obtain a modified conjugated diene polymer mixture (C).
A method for producing a modified conjugated diene-based polymer mixture,
The modified conjugated diene-based polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 or more and 4.5 or less,
Weight average of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B)
The molecular weight difference (ΔMw) is 50×10 ⁴ or more.
A method for producing a modified conjugated diene-based polymer mixture. The modified conjugated diene polymer (A
) and the modified conjugated diene-based polymer (B) to a mixing mass ratio ((A)/(B)) of 90/1
adjust from 0 to 40/60,
The method for producing the modified conjugated diene-based polymer mixture according to claim 1. The method for producing a modified conjugated diene polymer mixture according to claim 1 or 2, wherein the modified conjugated diene polymer (A) has an Mw of 100 x ¹⁰⁴ or more and 300 x ¹⁰⁴ or less. Adjusting the modified conjugated diene-based polymer mixture (C) to a modification rate of 50% by mass or more with respect to the total amount of the conjugated diene-based polymer,
A method for producing a modified conjugated diene-based polymer mixture according to any one of claims 1 to 3 . 3 of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B)
The contraction factor (g') by D-GPC is 0.70 or more and 1.0 or less.
A method for producing a modified conjugated diene-based polymer mixture according to any one of claims 1 to 4 . 3 of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B)
The contraction factor (g') by D-GPC is 0.30 or more and less than 0.70.
A method for producing a modified conjugated diene-based polymer mixture according to any one of claims 1 to 4 . The modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) are
Having a functional group represented by the following general formula (1) at the polymerization initiation end,
A method for producing a modified conjugated diene-based polymer mixture according to any one of claims 1 to 6 .

(In the general formula (1), R ¹ and R ² are selected from the group consisting of an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 14 carbon atoms, and an aryl group having 6 to 20 carbon atoms. and may be the same or different, wherein R ¹ and R ² may combine to form a ring structure with the adjacent nitrogen atoms, in which case R ¹ and R ² are hydrocarbon groups having a total of 4 to 12 carbon atoms.R ¹ and R ² may have an unsaturated bond or a branched structure.) The modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) are
Having a functional group represented by the general formula (1) at the polymerization initiation terminal, and at a terminal different from the polymerization initiation terminal having the functional group represented by the general formula (1), an alkoxysilyl group and having functional groups containing amines,
The method for producing the modified conjugated diene polymer mixture according to claim 7 . The modified conjugated diene-based polymer (B) has a modification rate of 5 with respect to the total amount of the conjugated diene-based polymer.
It is 0% by mass or more, and the modification rate of the component with a molecular weight that is 1/2 of the molecular weight of the peak top in the molecular weight curve, or the molecular weight of the peak top with the smallest molecular weight when there are a plurality of the peak tops, is the modified conjugate The modification rate is 1/2 or more of the total amount of the diene-based polymer, and the nitrogen content in the modified conjugated diene-based polymer (B) is 3 mass ppm or more and 70 mass ppm
is less than or equal to m
A method for producing a modified conjugated diene-based polymer mixture according to any one of claims 1 to 6 .