CN110655697B

CN110655697B - Method for producing modified conjugated diene polymer mixture

Info

Publication number: CN110655697B
Application number: CN201910531216.3A
Authority: CN
Inventors: 京美纪; 笹谷荣治
Original assignee: Asahi Kasei Corp
Current assignee: Asahi Kasei Corp
Priority date: 2018-06-28
Filing date: 2019-06-19
Publication date: 2021-12-21
Anticipated expiration: 2039-06-19
Also published as: CN110655697A; JP2020007532A; JP7280115B2; KR20200001996A; KR102165495B1

Abstract

Disclosed is a method for producing a modified conjugated diene polymer mixture which has excellent hysteresis loss properties and an excellent balance between abrasion resistance and processability when a sulfide containing a silica-based inorganic filler is used. In the method for producing the modified conjugated diene polymer mixture, the weight average molecular weight (Mw) measured by GPC is 70X 10⁴300X 10 above⁴The modified conjugated diene polymer (A) has Mw of 10X 10 as measured by GPC⁴Above and less than 70 × 10⁴The modified conjugated diene polymer (B) of (a) is continuously polymerized using one or more reactors, and a polymer solution containing the modified conjugated diene polymer (a) and a polymer solution containing the modified conjugated diene polymer (B) are solution-mixed, followed by solvent removal to obtain a modified conjugated diene polymer mixture (C); wherein the modified conjugated diene polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 to 4.5.

Description

Method for producing modified conjugated diene polymer mixture

Technical Field

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

Background

In recent years, environmental concerns have become social demands, and there is an increasing demand for fuel economy in automobiles. And also high safety is required at the same time.

Specifically, from the viewpoint of fuel economy, a material for a tire having low resistance to a road surface during running of an automobile is required, and particularly, a material having low rolling resistance, that is, a material having low hysteresis loss is required for a tire tread which is in direct contact with a road surface.

From the viewpoint of high safety, a material having excellent wet skid resistance and practically sufficient fracture characteristics is required.

Conventionally, carbon black has been used in many cases as a reinforcing filler used in a tread portion of a tire, but in recent years, silica has been used in many cases in order to exhibit excellent low hysteresis loss properties and wet skid resistance.

It is considered that by introducing a functional group having affinity with silica into a rubber molecule, the mobility of the rubber molecule is suppressed, and excellent hysteresis loss resistance and wet skid resistance can be exhibited. From this idea, a technique of introducing a functional group having affinity for silicon oxide into a rubber molecule has been proposed.

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 modified conjugated diene polymers.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2015-131955

Patent document 2: japanese patent laid-open publication No. 2016-

Disclosure of Invention

Problems to be solved by the invention

However, in recent years, there has been a demand for a method of efficiently producing a modified conjugated diene polymer composition having an excellent balance between wear resistance and processability while further improving low hysteresis loss properties.

Accordingly, an object of the present invention is to provide a method for efficiently producing a modified conjugated diene polymer mixture having excellent hysteresis loss and excellent balance between abrasion resistance and processability when a sulfide containing a silica-based inorganic filler is contained.

Means for solving the problems

The present inventors have conducted intensive studies to solve the above problems, and as a result, have found that a modified conjugated diene polymer mixture having an excellent balance of low hysteresis loss, wear resistance and processability in the case of a sulfide containing a silica-based inorganic filler can be produced by mixing modified conjugated diene polymers (a) and (B) having different weight average molecular weights (Mw), and that a modified conjugated diene polymer mixture having an excellent balance of low hysteresis loss, wear resistance and processability in the case of a sulfide produced through 1 finishing step can be efficiently produced by mixing two different modified conjugated diene polymers in a solution state after polymerization and removing the solvent, thereby completing the present invention.

Namely, the present invention is as follows.

[1]

A process for producing a modified conjugated diene polymer mixture, which comprises,

continuously polymerizing a modified conjugated diene polymer (A) having a weight average molecular weight (Mw) of 70X 10 as measured by GPC (gel permeation chromatography) and a modified conjugated diene polymer (B) each using one or more reactors⁴300X 10 above⁴The modified conjugated diene polymer (B) has an Mw of 10X 10 as measured by GPC⁴Above and less than 70 × 10⁴，

Mixing a polymer solution containing the modified conjugated diene polymer (A) with a polymer solution containing the modified conjugated diene polymer (B),

then, the solvent is removed to obtain a modified conjugated diene polymer mixture (C),

wherein the modified conjugated diene polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 to 4.5.

[2]

The method for producing a modified conjugated diene polymer mixture according to [1], wherein a mixing mass ratio ((A)/(B)) of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) in the modified conjugated diene polymer mixture (C) is adjusted to 90/10 to 40/60.

[3]

As described above [1]Or [ 2]]The process for producing a modified conjugated diene polymer mixture as described in (1), wherein the modified conjugated diene polymer (A) has an Mw of 100X 10⁴300X 10 above⁴The following.

[4]

As described above [1]～[3]The method for producing the modified conjugated diene polymer mixture according to any one of the above methods, wherein the difference (Δ Mw) between the weight average molecular weights of the modified conjugated diene polymer (A) and the modified conjugated diene polymer (B) is 50 × 10⁴The above.

[5]

The process for producing a modified conjugated diene polymer mixture according to any one of the above [1] to [4], wherein a modification ratio of the modified conjugated diene polymer mixture (C) to the total amount of the conjugated diene polymers is adjusted to 50% by mass or more.

[6]

The process for producing a modified conjugated diene polymer mixture according to any one of [1] to [5], wherein the shrinkage factor (g') of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) is 0.70 or more and 1.0 or less as measured by 3D-GPC.

[7]

The method for producing a modified conjugated diene polymer mixture according to any one of [1] to [5], wherein a shrinkage factor (g') of the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) is 0.30 or more and less than 0.70 as measured by 3D-GPC.

[8]

The process for producing a modified conjugated diene polymer mixture according to any one of the above [1] to [7], wherein,

the modified conjugated diene polymer (a) and/or the modified conjugated diene polymer (B) has a functional group represented by the following general formula (1) at a polymerization initiation end.

[ solution 1]

(in the above general formula (1), R¹And R²Is any one 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, R¹And R²May be the same or different. Here, R¹And R²May be bonded to form a cyclic structure together with the adjacent nitrogen atom, R in this case¹And R²Is a hydrocarbon group having 4 to 12 carbon atoms in total. R¹And R²May have an unsaturated bond or a branched structure. )

[9]

The method for producing a modified conjugated diene polymer mixture according to [8], wherein the modified conjugated diene polymer (A) and/or the modified conjugated diene polymer (B) has a functional group represented by the general formula (1) at a polymerization initiation end, and has a functional group containing an alkoxysilyl group and an amine at a terminal different from the polymerization initiation end having the functional group represented by the general formula (1).

[10]

The process for producing a modified conjugated diene polymer mixture according to any one of the above [1] to [7], wherein the modified conjugated diene polymer (B) has a modification ratio of 50% by mass or more with respect to the total amount of the conjugated diene polymer, and a modification ratio of 1/2% by mass or more of the molecular weight of a peak having the smallest molecular weight in a molecular weight curve or when a plurality of the peak tops are present, of the modified conjugated diene polymer having a modification ratio of 1/2 or more with respect to the total amount of the modified conjugated diene polymer; the modified conjugated diene polymer (B) contains nitrogen in an amount of 3 to 70 mass ppm.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide a method for producing a modified conjugated diene polymer mixture which is capable of efficiently producing a modified conjugated diene polymer mixture having excellent hysteresis loss properties and an excellent balance between wear resistance and processability when a sulfide containing a silica-based filler is contained.

Detailed Description

The following describes in detail a specific embodiment of the present invention (hereinafter referred to as "the present embodiment").

The following embodiments are merely examples for illustrating the present invention, and the present invention is not limited to the following embodiments and can be carried out by being variously modified within the scope of the gist thereof.

[ Process for producing modified conjugated diene Polymer mixture ]

In the method for producing a modified conjugated diene polymer mixture according to the present embodiment,

the weight average molecular weight (Mw) measured by GPC (gel permeation chromatography) was 70X 10⁴300X 10 above⁴The modified conjugated diene polymer (A) has Mw of 10X 10 as measured by GPC⁴Above and less than 70 × 10⁴The modified conjugated diene polymer (B) is continuously polymerized in at least one reactor,

(modified conjugated diene Polymer (A) and modified conjugated diene Polymer (B))

The modified conjugated diene polymer (A) had a weight average molecular weight (Mw) of 70X 10 as measured by GPC (gel permeation chromatography)⁴300X 10 above⁴Hereinafter, the modified conjugated diene polymer (B) has Mw of 10X 10 as measured by GPC⁴70X 10 above⁴The following.

In the method for producing a modified conjugated diene polymer mixture according to the present embodiment, the 2 modified conjugated diene polymers (a) and (B) are continuously polymerized using 1 or more reactors to obtain respective polymer solutions.

(methods for producing modified conjugated diene Polymer (A) and modified conjugated diene Polymer (B))

< polymerization step >

In the polymerization step of the modified conjugated diene polymers (a) and (B), at least the conjugated diene compound is polymerized using an organic lithium compound as a polymerization initiator to obtain a conjugated diene polymer.

The polymerization step is preferably a polymerization step in which a growth reaction by living anionic polymerization is carried out, whereby a conjugated diene polymer having an active end can be obtained, and a modified conjugated diene polymer having a high modification ratio tends to be obtained.

In the polymerization step, at least the conjugated diene compound is polymerized, and the conjugated diene compound and the aromatic vinyl compound are copolymerized as necessary to obtain a conjugated diene copolymer.

The conjugated diene compound is not particularly limited as long as it is a copolymerizable monomer, and is preferably a conjugated diene compound having 4 to 12 carbon atoms per 1 molecule, and more preferably a conjugated diene compound having 4 to 8 carbon atoms per 1 molecule.

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 preferable in terms of ease of industrial availability. These may be used alone or in combination of two or more.

The aromatic vinyl compound is not particularly limited as long as it is a monomer copolymerizable with the conjugated diene compound, and a monovinyl aromatic compound is preferred.

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

The conjugated diene polymer obtained in the polymerization step may be a random copolymer or a block copolymer.

In order to form the conjugated diene polymer into a rubbery polymer, the conjugated diene compound is used in an amount of preferably 40% by mass or more, more preferably 55% by mass or more, based on the total monomers of the conjugated diene polymer.

Examples of the random copolymer include, but are not limited to, random copolymers composed of a conjugated diene compound and an aromatic vinyl compound, such as a butadiene-isoprene random copolymer and a random copolymer composed of 2 or more conjugated diene compounds, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer.

The composition distribution of each monomer in the copolymer chain is not particularly limited, and examples thereof include a completely random copolymer having a nearly statistically random composition and a tapered (gradient) random copolymer having a tapered composition. The composition of the conjugated diene in the form of a bond, i.e., a1, 4-bond, a1, 2-bond, etc., may be uniform or may have a distribution.

Examples of the block copolymer include, but are not limited to, a 2-type block copolymer (diblock) composed of 2 blocks, a 3-type block copolymer (triblock) composed of 3 blocks, and a 4-type block copolymer (tetrablock) composed of 4 blocks. The polymer constituting the 1 block may be a polymer composed of 1 kind of monomer, or a copolymer composed of 2 or more kinds of monomers. For example, when 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", a copolymer of 1, 3-butadiene and styrene is represented by "B/S", and a polymer block composed of styrene is represented by "S", the block copolymers are represented by B-B/I2 type block copolymers, B-B/S2 type block copolymers, S-B2 type block copolymers, B-B/S-S3 type block copolymers, S-B-S-B4 type block copolymers, and the like.

In the above formula, the boundaries of the blocks do not necessarily need to be clearly distinguished. In addition, in the case where 1 polymer block is a copolymer composed of two monomers a and B, a and B in the block may be uniformly distributed or may be distributed in a tapered manner.

< polymerization initiator >

As the polymerization initiator in the polymerization step, an organolithium compound can be used.

Examples of the organic lithium compound include, but are not limited to, low molecular weight compounds and soluble oligomer organic lithium compounds.

Examples of the organic lithium compound include a compound having a carbon-lithium bond, a compound having a nitrogen-lithium bond, and a compound having a tin-lithium bond in the form of a bond between the organic group and lithium.

The amount of the polymerization initiator to be used is preferably determined in accordance with the molecular weight of the target conjugated diene polymer or modified conjugated diene polymer. The amount of the monomer such as a conjugated diene compound used relative to the amount of the polymerization initiator used is related to the degree of polymerization. That is, there is a tendency to be correlated with the number average molecular weight and/or the weight average molecular weight. Therefore, in order to increase the molecular weight, adjustment may be made in a direction to decrease the polymerization initiator; in order to decrease the molecular weight, adjustment may be made in the direction of increasing the amount of the polymerization initiator.

The organic lithium compound as a polymerization initiator is preferably an alkyl lithium compound in view of easiness of industrial availability and easiness of control of polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal is obtained.

Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and lithium stilbene. The alkyl lithium compound is preferably n-butyl lithium or sec-butyl lithium in view of easiness of industrial availability and easiness of control of polymerization reaction.

From the viewpoint of using one method of introducing a nitrogen atom into a conjugated diene polymer, the compound having nitrogen-lithium (hereinafter sometimes referred to as an aminolithium compound) as a polymerization initiator is preferably an alkyllithium compound having a substituted amino group or a dialkylaminolithium compound.

In this case, a conjugated diene polymer having a functional group represented by the following general formula (1) at the polymerization initiation end and having a nitrogen atom constituting an amino group, and modified conjugated diene polymers (a) and (B) can be obtained.

Introduction of a nitrogen atom into a conjugated diene polymer tends to improve hysteresis loss characteristics and wet skid resistance.

[ solution 2]

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

[ solution 3]

Examples of the compound represented by the formula (2) include 1-pyrrolidinium (1-lithiopyrolidide), 1-piperidinium (1-lithitoperidine), 1-azepane lithium (1-lithioazacyclohexapentane), 1-azacyclooctane lithium, 1-azacycloundecanium, diethylaminolithium, dibutylaminoithium, dihexylaminthium, 6-lithium-1, 3, 3-trimethyl-6-azabicyclo [3.2.1] octane, ethylbutylaminolithium, ethylhexylaminolithium, butylhexylaminolithium, methylphenylaminoithium, benzylmethylaminolithium, 1-lithium-1, 2,3, 4-tetrahydropyridine, and the like.

The compound represented by the formula (2) is not limited to these compounds, and includes analogs thereof if the above conditions are satisfied.

From the viewpoint of reducing hysteresis loss of a resin composition using the modified conjugated diene polymer mixture obtained in the present embodiment, the compound represented by the formula (2) is preferably 1-pyrrolidinium lithium, 1-piperidinium lithium, 1-azepane lithium, dibutylaminolithium, 6-lithium-1, 3, 3-trimethyl-6-azabicyclo [3.2.1] octane, 1-lithium-1, 2,3, 4-tetrahydropyridine, or the like.

More preferably 1-lithium pyrrolidine, 1-lithium piperidine, and 1-lithium azepane, and still more preferably 1-lithium piperidine and 1-lithium azepane.

The lithium amide compound can be synthesized by a known method. For example by reacting a secondary amine with an organolithium 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. Specific examples thereof include aliphatic hydrocarbons such as butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene, and hydrocarbons composed of a mixture of these hydrocarbons.

Examples of the secondary amine include, but are not limited to, compounds represented by the following general formula (3).

[ solution 4]

In the above formula (3), R¹And R²Is any one 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, R¹And R²May be the same or different. R¹And R²May be bonded to form a cyclic structure together with the adjacent nitrogen atom, R in this case¹And R²Is a hydrocarbon group having 4 to 12 carbon atoms in total. R¹And R²May have an unsaturated bond or a branched structure.

Examples of the compound represented by the formula (3) include pyrrolidine, piperidine, azepane, azocane, 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 compound represented by the above formula (3) is not limited to these, and if the above conditions are satisfied, analogues of these are included.

The compound represented by the formula (3) is preferably pyrrolidine, piperidine, azepane, dibutylamine, 1,3, 3-trimethyl-6-azabicyclo [3.2.1] octane, or 1,2,3, 4-tetrahydropyridine, from the viewpoint of reducing hysteresis loss of the modified conjugated diene polymer mixture obtained in the present embodiment. More preferably pyrrolidine, piperidine, azepane. Piperidine and azepane are more preferable.

These organolithium compounds having a substituted amino group may be used in the form of an organomonolithium compound which is a soluble oligomer by reacting a copolymerizable monomer, for example, a monomer such as 1, 3-butadiene, isoprene or styrene, in a small amount.

The organic lithium compound is preferably an alkyl lithium compound in view of easiness of industrial availability and easiness of control of polymerization reaction. In this case, a conjugated diene polymer having an alkyl group at the polymerization initiation end is obtained.

Examples of the alkyllithium compound include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and lithium stilbene.

The alkyllithium compound is preferably n-butyllithium or sec-butyllithium in view of easiness of industrial availability and easiness of control of polymerization reaction.

These organic lithium compounds may be used alone or in combination of two or more.

In addition, other organometallic compounds may be used in combination. Examples of the organometallic compound include an alkaline earth metal compound, another alkali metal compound, and another organometallic compound. Examples of the alkaline earth metal compound include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organic strontium compounds. In addition, alkoxide, sulfonate, carbonate and amide compounds of alkaline earth metals are also included. Examples of the organomagnesium compound include dibutylmagnesium and ethylbutylmagnesium. Examples of the other organometallic compounds include organoaluminum compounds.

The polymerization reaction in the polymerization step is preferably carried out as a continuous polymerization reaction.

In the continuous system, polymerization can be carried out using 1 or 2 or more reactors connected to each other.

As the continuous reactor, for example, a tank type or a tubular type reactor with a stirrer is used. In the continuous type, it is preferable that the monomer, the inert solvent, and the polymerization initiator are continuously charged into a reactor, a polymer solution containing the polymer is obtained in the reactor, and the polymer solution is continuously discharged.

The polymerization step is preferably carried out in an inert solvent. Examples of the inert solvent include hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons. Specific examples of the hydrocarbon solvent 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 composed of a mixture of these.

Before being fed to the polymerization reaction, by treating allenes (allenes) and acetylenes as impurities with an organometallic compound, a conjugated diene polymer having a high concentration of active terminals tends to be obtained, and modified conjugated diene polymers (a) and (B) having a high modification ratio tend to be obtained, and thus are preferable.

A polar compound may be added in the polymerization step. The addition of the polar compound tends to allow the aromatic vinyl compound and the conjugated diene compound to be randomly copolymerized and also to be used as a vinylating agent for controlling the microstructure of the conjugated diene portion. There is a tendency that the polymerization reaction is also effective in acceleration or the like.

Examples of the polar compound include, but are not limited to, ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2, 2-bis (2-tetrahydrofuryl) propane; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine and quinuclidine; alkali metal alkoxide compounds such as potassium tert-butoxide, sodium tert-butoxide, and sodium pentoxide; phosphine compounds such as triphenylphosphine; and so on.

These polar compounds may be used alone or in combination of two or more.

The amount of the polar compound to be used is not particularly limited and may be selected according to the purpose, etc., and is preferably 0.01 mol or more and 100 mol or less based on 1 mol of the polymerization initiator. Such a polar compound (vinylating agent) can be used in an appropriate amount depending on the desired vinyl bonding amount as a regulator of the microstructure of the conjugated diene portion of the resulting polymer.

Most of the polar compounds have an effective randomizing effect in the copolymerization of the conjugated diene compound and the aromatic vinyl compound, and tend to be useful as a distribution regulator for the aromatic vinyl compound and a regulator for the styrene block amount.

As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, for example, a method of initiating a copolymerization reaction of the whole amount of styrene and a part of 1, 3-butadiene and then intermittently adding the rest of 1, 3-butadiene in the middle of the copolymerization reaction as described in Japanese patent laid-open No. 59-140211 can be used.

The modified conjugated diene polymer (B) constituting the modified conjugated diene polymer mixture obtained in the present embodiment is preferably such that the modification ratio of the low-molecular-weight component having a molecular weight of 1/2, which is equal to or higher than the modification ratio of the total amount of the conjugated diene polymers, of the peak top in the GPC curve or the peak top having the smallest molecular weight when a plurality of peak tops are present, is 1/2 or more.

In this regard, it is considered that the low molecular weight component in the entire polymer contributes to the processability of the polymer, and the modified conjugated diene polymer (B) tends to have a lower molecular weight than the modified conjugated diene polymer (a) and to have excellent processability in producing a sulfide when the modification ratio of the low molecular weight component of the modified conjugated diene polymer (B) is in the above range.

In order to obtain the modified conjugated diene polymer, it is effective to obtain the conjugated diene polymer by a polymerization method in which termination of the growth reaction or chain transfer hardly occurs.

Therefore, ultra-high purity of the monomer and solvent introduced into the polymerization reactor is required to be at a level above the prior art.

Therefore, in the monomer components used, the total amount of impurities is preferably 30ppm or less, and with respect to the content concentration (mass) of impurities such as allenes, acetylenes, primary amines and secondary amines, the allenes are preferably 20ppm or less, more preferably 10ppm or less, the acetylenes are preferably 20ppm or less, more preferably 10ppm or less, and the primary amines and secondary amines are preferably 4ppm or less, more preferably 2ppm or less in total nitrogen content.

Examples of the allenes include, but are not limited to, allenes and 1, 2-butadienes. Examples of the acetylene group include, but are not limited to, ethyl acetylene and vinyl acetylene. Examples of the primary and secondary amines include, but are not limited to, methylamine and dimethylamine.

By thus ultrahigh-purifying the monomer and the solvent, as described later, even in the modified conjugated diene polymer having a small content of nitrogen of 3 to 70 mass ppm, the modification ratio of the low-molecular-weight component can be made 1/2 or more with respect to the modification ratio of the total amount of the conjugated diene polymer.

Ultra-high purity of the monomer and the solvent can be achieved by sufficiently purifying all of the monomer and the solvent used in the polymerization.

In the purification of butadiene as a monomer, it is important to remove not only the polymerization inhibitor but also dimethylamine, N-methyl-gamma-aminobutyric acid and the like which may adversely affect the anionic polymerization. As a method for removing these, for example, a method in which 1, 3-butadiene containing a polymerization inhibitor is washed with water using low-oxygen water having an oxygen concentration of less than 2mg/L as washing water, and then the polymerization inhibitor in the 1, 3-butadiene is removed can be mentioned.

In the purification of styrene as a monomer, it is important to remove phenylacetylenes and the like which may adversely affect anionic polymerization. Examples of the method for removing phenylacetylenes include a method in which a hydrogenation reaction is carried out using a palladium-supported alumina catalyst.

In the purification of n-hexane as a polymerization solvent, it is important to remove moisture which may adversely affect anionic polymerization. Examples of the method for removing the water include a method using γ -alumina, synthetic zeolite, or the like. Among these, the method of using synthetic zeolite is preferred, and synthetic zeolite having a large pore diameter is preferred, and the pore diameter is more preferably 0.35nm or more, and still more preferably 0.42nm or more.

As a polymerization method in which the termination of the growth reaction or chain transfer rarely occurs, a method of controlling the polymerization temperature and the monomer conversion rate is effective.

The polymerization temperature is preferably lower from the viewpoint of suppressing the stop of the growth reaction or chain transfer, but from the viewpoint of productivity, the polymerization temperature is preferably a temperature at which living anionic polymerization sufficiently proceeds, specifically, preferably 0 ℃ or more, preferably 80 ℃ or less. More preferably 50 ℃ to 75 ℃. In addition, the reaction with the modifier is preferably carried out so that the conversion of the whole monomers is less than 99% by mass. By adding the modifier at a stage where the monomer remains in the polymerizer and reacting the growing polymer chain with the modifier while the monomer is not consumed, it is possible to suppress the formation of a polymer whose terminal is not modified and to suppress the occurrence of other side reactions. More preferably, the conversion is less than 98 mass%.

In the modified conjugated diene polymers (a) and (B) constituting the modified conjugated diene polymer mixture obtained in the present embodiment, the amount of the bonded conjugated diene in the conjugated diene polymer or the modified conjugated diene polymers (a) and (B) obtained in the polymerization step is not particularly limited, and is 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 the bonded aromatic vinyl group in the conjugated diene polymer or modified conjugated diene polymers (a) and (B) is not particularly limited, but is preferably 0 mass% to 60 mass%, more preferably 20 mass% to 45 mass%.

When the amount of the conjugated diene bonded and the amount of the aromatic vinyl bonded are within the above ranges, the resulting vulcanizate tends to have a more excellent balance of hysteresis loss resistance and wet skid resistance, and also more excellent abrasion resistance and fracture properties. The amount of the bonded aromatic vinyl group can be measured by ultraviolet absorption of the phenyl group, and the amount of the bonded conjugated diene can be determined. Specifically, the measurement can be carried out by the method described in the examples described later.

In the conjugated diene polymer or modified conjugated diene polymer, the vinyl bond amount in the conjugated diene bond unit is not particularly limited, but is preferably 10 mol% or more and 75 mol% or less, and more preferably 20 mol% or more and 65 mol% or less. When the vinyl bond content is in the above range, the balance between hysteresis loss resistance and wet skid resistance after production of a vulcanizate, and the wear resistance and fracture strength tend to be more excellent. Here, in the case where the modified diene polymer is a copolymer of butadiene and styrene, the vinyl bond amount (1, 2-bond amount) in the butadiene bond unit can be determined by Hampton method (r.r. Hampton, Analytical Chemistry,21,923 (1949)). Specifically, the measurement can be carried out by the method described in the examples below.

With respect to the microstructures of the modified conjugated diene polymers (a) and (B), when the amount of each bond in the modified conjugated diene polymers (a) and (B) is in the above range and the glass transition temperatures of the modified conjugated diene polymers (a) and (B) are in the range of-45 ℃ to-15 ℃, there is a tendency that a sulfide having a further excellent balance between low hysteresis loss properties and wet skid resistance can be obtained. The glass transition temperature is determined by recording a DSC curve while raising the temperature in a predetermined temperature range in accordance with ISO 22768:2006, and setting the peak top (inflection point) of the DSC differential curve as the glass transition temperature.

When the modified conjugated diene polymers (a) and (B) are a conjugated diene-aromatic vinyl copolymer, the number of blocks in which 30 or more aromatic vinyl units are linked is preferably small or none. More specifically, in the case where the copolymer is a butadiene-styrene copolymer, in a known method of decomposing the copolymer by Kolthoff (method described in i.m. Kolthoff, et al, j.polym.sci.1,429 (1946)), and analyzing the amount of polystyrene insoluble in methanol, a block segment in which 30 or more aromatic vinyl units are linked is preferably 5.0 mass% or less, more preferably 3.0 mass% or less, with respect to the total amount of the copolymer.

When the modified conjugated diene polymer (a) or (B) is a conjugated diene-aromatic vinyl copolymer before modification, the aromatic vinyl unit is preferably present alone in a large proportion. Specifically, when the copolymer is a butadiene-styrene copolymer, it is preferable that the amount of the isolated styrene is 40 mass% or more and the number of the linked styrene structures having 8 or more styrene chains is 5 mass% or less based on the total amount of the linked styrene when the copolymer is decomposed by a method known as a method of Tianzhong et al (Polymer,22,1721(1981)) based on ozonolysis and analyzed for styrene chain distribution by GPC. In this case, the resulting vulcanized rubber has excellent properties 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 according to the present embodiment has an Mw of 70 × 10 measured by GPC⁴300X 10 above⁴The modified conjugated diene polymer (B) has an Mw of 10X 10⁴Above and less than 70 × 10⁴。

In this way, the Mw of each polymer in the continuous polymerization can be controlled by adjusting the polymerization temperature, the amount of monomer to be added, and the amount of polymerization initiator to be added in each polymerization step.

< modification step >

After the polymerization step, the conjugated diene polymer is subjected to a modification step to obtain modified conjugated diene polymers (a) and (B).

In the modification step, the conjugated diene polymer obtained by the above method is reacted with a predetermined modifier having a bonding group that reacts with the active end of the conjugated diene polymer and further having a specific functional group that has affinity or bonding reactivity with the filler.

In addition, it is preferable to perform the modification step immediately after the polymerization step. In this case, a modified conjugated diene polymer having a high modification ratio tends to be obtained.

When a compound having a monofunctional or 2-functional linking group is used as the modifier, a linear terminal-modified diene polymer can be obtained; when a polyfunctional compound having 3 or more functional groups as a linking group is used, a branched modified diene polymer can be obtained.

As the modifier, a monofunctional or polyfunctional compound containing at least one element of nitrogen, silicon, tin, phosphorus, oxygen, sulfur, and halogen is preferably used. In addition, an onium structure can be introduced into the modified conjugated diene polymer by adding a terminal modifier containing an onium generating agent to carry out the reaction. Further, a modifier having a plurality of functional groups containing these elements in a molecule or a modifier having a plurality of functional groups containing these elements may be used.

The modifier is preferably a modifier having a functional group with little or no active hydrogen, such as a hydroxyl group, a carboxyl group, a primary amino group, or a secondary amino group. The active hydrogen tends to deactivate the active terminal of the conjugated diene polymer.

[ modifier ]

The modifier is specifically described below.

Examples of the nitrogen-containing compound include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, carbonyl compounds containing a nitrogen group, vinyl compounds containing a nitrogen group, epoxy compounds containing a nitrogen group, and the like.

Examples of the silicon-containing compound include, but are not limited to, halogenated silicon compounds, epoxidized silicon compounds, vinyl silicon compounds, silicon alkoxide compounds containing a nitrogen-containing group, and the like.

Examples of the tin-containing compound include, but are not limited to, a tin halide compound, an organotin carboxylate compound, and the like.

Examples of the phosphorus-containing compound include, but are not limited to, phosphite compounds and phosphine compounds.

Examples of the oxygen-containing compound include, but are not limited to, epoxy compounds, ether compounds, ester compounds, and the like.

Examples of the sulfur-containing compound include, but are not limited to, mercapto derivatives, thiocarbonyl compounds, isothiocyanates, and the like.

Examples of the halogen-containing compound include, but are not limited to, the above-mentioned silicon halide compound and tin halide compound.

Examples of the onium generator include, but are not limited to, a protected amine compound (ammonium generator) capable of forming a primary or secondary amine, a protected phosphine compound (phosphonium generator) capable of forming a phosphine hydride, and a compound (oxonium or sulfonium generator) capable of forming a hydroxyl group or a thiol group. Examples of the functional group to which the modified conjugated diene polymer is bonded include carbonyl groups (such as ketones and esters), unsaturated groups such as vinyl groups, epoxy groups, silicon halide groups, and silicon alkoxide groups.

The modifier preferably has a nitrogen-containing functional group, and the nitrogen-containing functional group is preferably an amine compound having no active hydrogen, and examples thereof include a tertiary amine compound, a protected amine compound in which the active hydrogen is substituted with a protecting group, and an imine compound represented by the general formula — N ═ C.

Examples of the isocyanate compound of the nitrogen-containing compound as the modifier include, but are not limited to, 2, 4-tolylene diisocyanate, 2, 6-tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, 1,3, 5-benzene triisocyanate, and the like.

Examples of the isocyanuric acid derivative include, but are not limited to, 1,3, 5-tris (3-trimethoxysilylpropyl) isocyanurate, 1,3, 5-tris (3-triethoxysilylpropyl) isocyanurate, 1,3, 5-tris (oxirane-2-yl) -1,3, 5-triazinane-2, 4, 6-trione, 1,3, 5-tris (isocyanatomethyl) -1,3, 5-triazinane-2, 4, 6-trione, and 1,3, 5-trivinyl-1, 3, 5-triazinane-2, 4, 6-trione.

Examples of the nitrogen group-containing carbonyl compound 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 '-bis (diethylamino) benzophenone, 4' -bis (dimethylamino) benzophenone, methyl-2-pyridinone, methyl-4-pyridinone, propyl-2-pyridinone, di-4-pyridinone, 2-benzoylpyridine, methyl-2-imidazolidinone, methyl-2-pyridinone, methyl-2-pyrimidinone, and methyl-pyrimidinone, N, N ' -tetramethylurea, N-dimethyl-N ', N ' -diphenylurea, N-diethylcarbamic acid methyl ester, N-diethylacetamide, N-dimethyl-N ', N ' -dimethylaminoacetamide, N-dimethylpyridinecarboxamide, N-dimethylisonicotinamide, and the like.

Examples of the nitrogen group-containing vinyl compound include, but are not limited to, N-dimethylacrylamide, N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N, n-bistrimethylsilylacrylamide, morpholinoacrylamide, 3- (2-dimethylaminoethyl) styrene, (dimethylamino) dimethyl-4-vinylphenylsilane, 4 '-ethenylbis (N, N-dimethylaniline), 4' -ethenylbis (N, N-diethylaniline), 1-bis (4-morpholinophenyl) ethylene, 1-phenyl-1- (4-N, N-dimethylaminophenyl) ethylene and the like.

Examples of the nitrogen group-containing epoxy compound include, but are not limited to, an epoxy group-containing hydrocarbon compound bonded to an amino group, and may further have an epoxy group bonded to an ether group. Examples thereof include compounds represented by the general formula (4).

[ solution 5]

In the formula (4), R is a hydrocarbon group having a valence of 2 or more, or an organic group having a valence of 2 or more, which has at least one polar group selected from a polar group having oxygen such as ether, epoxy, ketone, etc., a polar group having sulfur such as thioether, thioketone, etc., a polar group having nitrogen such as tertiary amino, imino, etc.

The hydrocarbon group having a valence of 2 or more 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. The hydrocarbon group having 1 to 20 carbon atoms is preferable. Examples thereof include methylene, ethylene, butylene, cyclohexylene, 1, 3-bis (methylene) -cyclohexane, 1, 3-bis (ethylene) -cyclohexane, o-phenylene, m-phenylene, p-phenylene, m-xylene, p-xylene, and bis (phenylene) -methane.

In the above formula (4), R¹、R⁴Is a hydrocarbon group having 1 to 10 carbon atoms, R¹、R⁴May be the same or different from each other.

R²、R⁵Is hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, R²、R⁵May be the same or different from each other.

R³Is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (5).

R¹、R²、R³May have a ring structure formed by bonding to each other.

In addition, R³In the case of a hydrocarbon group, the group may have a cyclic structure in which R and R are bonded to each other. When the cyclic structure is as described above, it may be R³The bonded N and R are in direct bonding.

In the formula (4), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

[ solution 6]

In the above formula (5), R¹、R²With R of the above formula (4)¹、R²Are defined as such, R¹、R²May be the same or different from each other.

The epoxy compound containing a nitrogen group used as the modifier is preferably a compound having a hydrocarbon group containing an epoxy group, and more preferably a compound having a hydrocarbon group containing a glycidyl group.

Examples of the hydrocarbon group containing an epoxy group bonded to an amino group or an ether group include a glycidylamino group, a diglycidylamino group, and a glycidyloxy group. Further preferable molecular structures are compounds containing an epoxy group and having a glycidylamino group, a diglycidylamino group and a glycidyloxy group, respectively, and examples thereof include compounds represented by the following general formula (6).

[ solution 7]

In the above formula (6), R is as defined as R in the above formula (4), and R is⁶Is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (7).

R⁶In the case of a hydrocarbon group, R may be bonded to each other to form a cyclic structure, and in this case, R may be bonded to R⁶The bonded N and R may be in the form of a direct bond.

In the formula (6), n is an integer of 1 or more, and m is an integer of 0 or 1 or more.

[ solution 8]

As the epoxy compound containing a nitrogen group used as a modifier, a compound having 1 or more diglycidylamino groups and 1 or more glycidyloxy groups in the molecule is more preferable.

Examples of the nitrogen group-containing epoxy compound used as the modifier include, but are not limited to, N-diglycidyl-4-glycidoxyaniline, 1-N, N-diglycidyl aminomethyl-4-glycidoxy-cyclohexane, 4- (4-glycidoxyphenyl) - (N, N-diglycidyl) aniline, 4- (4-glycidoxyphenoxy) - (N, N-diglycidyl) aniline, 4- (4-glycidoxybenzyl) - (N, N-diglycidyl) aniline, 4- (N, N' -diglycidyl-2-piperazinyl) -glycidoxybenzene, 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, N-diglycidyl amino-4-glycidoxy-aniline, N-diglycidyl amino-4-glycidoxy-cyclohexane, N-diglycidyl amino-4-glycidoxy-phenyl-N, N-diglycidyl phenyl-4- (4-glycidoxypropyl) aniline, 1, 3-bis (N, N-diglycidyl amino-methyl) cyclohexane, N-glycidyloxy-phenyl-o-phenyl-4-phenyl-4- (4-glycidyloxy) aniline, N-diglycidyl phenyl-glycidyloxy-phenyl-4, N-diglycidyl amino-phenyl, N, n, N, N ', N' -tetraglycidyl m-xylylenediamine, 4-methylene-bis (N, N-diglycidylaniline), 1, 4-bis (N, N-diglycidylamino) cyclohexane, N, N, N ', N' -tetraglycidyl p-phenylenediamine, 4 '-bis (diglycidylamino) benzophenone, 4- (4-glycidylpiperazinyl) - (N, N-diglycidylamino) aniline, 2- [2- (N, N-diglycidylamino) ethyl ] -1-glycidylpyrrolidine, N, N-diglycidylaniline, 4' -diglycidyldibenzylmethylamine, N, N-diglycidylaniline, N, N-diglycidyl o-toluidine, N-diglycidyl aminomethylcyclohexane, and the like. Among these, N-diglycidyl-4-glycidoxyaniline and 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane are particularly preferable.

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

Examples of the silicon epoxide compound as a modifier include, but are not limited to, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, epoxy-modified silicone, and the like.

Examples of the silicon alkoxide compound as the modifier include, but are not limited to, tetramethoxysilane, tetraethoxysilane, triphenoxymethylsilane, and methoxy-substituted polyorganosiloxane.

Examples of the nitrogen group-containing alkoxysilane compound as the modifier include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3- (4-methyl-1-piperazinyl) propyltriethoxysilane, 1- [3- (triethoxysilyl) -propyl ] -3-methylhexahydropyrimidine, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyldiethoxysilane, N-phenyltrimethoxysilane, N-acetyltrimethoxysilane, N-ethylsilyltrimethoxysilane, N-1-hydroxysilane, N-hydroxyiminopropylmethyldiethoxysilane, N-1-hydroxysilane, N-p-N-p-hydroxysilane, N-p-hydroxysilane, N-p-, 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' -tetrakis (3-trimethoxysilylpropyl) ethylenediamine, 3-isocyanatopropyltrimethoxysilane, 3-cyanopropyltrimethoxysilane, 2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza Hetero-2-silacyclopentane, 2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1- (4-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2-dimethoxy-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2-dimethyl-1-aza-2-silacyclopentane, 2-dimethyl-1-aza-2-silacyclopentane, 2-dimethyl-1-aza-silacyclopentane, 2-dimethyl-ethyl-1-aza-silacyclopentane, 2-ethyl-2-silacyclopentane, 2-ethyl-methyl-ethyl-2-silacyclopentane, ethyl-methyl-ethyl-2-ethyl-methyl-ethyl-methyl-2-ethyl-methyl-ethyl-methyl-ethyl-2-ethyl-methyl-2-ethyl-methyl-ethyl-methyl-ethyl-methyl-2-ethyl-methyl-ethyl-methyl-ethyl-2-ethyl-methyl-ethyl-methyl-ethyl-2-ethyl-methyl-ethyl-methyl-ethyl-methyl-ethyl, 2, 2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, 2-dimethoxy-8- (4-methylpiperazinyl) methyl-1, 6-dioxa-2-silacyclooctane, 2-dimethoxy-8- (N, N-diethylamino) methyl-1, 6-dioxa-2-silacyclooctane and the like.

Examples of the protected amine compound capable of forming a primary or secondary amine, which is a modifier, include, but are not limited to, 4 '-vinylidene bis [ N, N-bis (trimethylsilyl) aniline ], 4' -vinylidene bis [ N, N-bis (triethylsilyl) aniline ], 4 '-vinylidene bis [ N, N-bis (t-butyldimethylsilyl) aniline ], 4' -vinylidene bis [ N-methyl-N- (trimethylsilyl) aniline ], 4 '-vinylidene bis [ N-ethyl-N- (trimethylsilyl) aniline ], 4' -vinylidene bis [ N-methyl-N- (triethylsilyl) aniline ], (N-methyl-N- (triethylsilyl) aniline), 4,4 ' -vinylidene bis [ N-ethyl-N- (triethylsilyl) aniline ], 4 ' -vinylidene bis [ N-methyl-N- (t-butyldimethylsilyl) aniline ], 4 ' -vinylidene bis [ 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-dimethylaminophenyl ] ethylene, and the like.

As the compound having an alkoxysilane and a protected amine in the molecule, which is a modifier, a protected amine compound capable of forming a primary or secondary amine, there may be mentioned, but not limited to, N-bis (trimethylsilyl) aminopropyltrimethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N-bis (trimethylsilyl) aminopropylmethyldiethoxysilane, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane, N-bis (triethylsilyl) aminopropylmethyldiethoxysilane, 3- (4-trimethylsilyl-1-piperazinyl) propyltriethoxysilane Alkyl, 3- (3-triethylsilyl-1-imidazolidinyl) propylmethyldiethoxysilane, 3- (3-trimethylsilyl-1-hexahydropyrimidinyl) propyltrimethoxysilane, 2-dimethoxy-1- (3-trimethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-diethoxy-1- (3-triethoxysilylpropyl) -1-aza-2-silacyclopentane, 2-dimethoxy-1- (4-trimethoxysilylbutyl) -1-aza-2-silacyclohexane, 2-dimethoxy-1- (3-dimethoxymethylsilylpropyl) -1-aza-2-silacyclohexane 2-silacyclopentane, 2-dimethoxy-1-phenyl-1-aza-2-silacyclopentane, 2-diethoxy-1-butyl-1-aza-2-silacyclopentane, 2-dimethoxy-1-methyl-1-aza-2-silacyclopentane, and the like.

Examples of tin halide compounds as modifiers include, but are not limited to, tin tetrachloride, tin tetrabromide, butyltin trichloride, octyltin trichloride, dimethyltin dibromide, dibutyltin dichloride, tributyltin chloride, trioctyltin chloride, triphenyltin chloride, 1, 2-bis (trichlorostannyl) ethane, 1, 2-bis (methyldichlorosilyl) ethane, 1, 4-bis (trichlorostannyl) butane, 1, 4-bis (methyldichlorosilyl) butane, and the like.

Examples of the organotin carboxylate compound as the modifier include, but are not limited to, ethyl tin tristearate, butyl tin tricaprylate, butyl tin tristearate, butyl tin trilaurate, dibutyltin dioctoate and the like.

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

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

Examples of the oxygen-containing compound as the modifier include, but are not limited to, polyglycidyl ethers such as ethylene glycol diglycidyl ether and glycerol triglycidyl ether, polyepoxy compounds such as 1, 4-diglycidyl benzene, 1,3, 5-triglycidyl benzene, polyepoxy liquid polybutadiene, epoxidized soybean oil and epoxidized linseed oil, ester compounds such as dimethyl adipate, diethyl adipate, dimethyl terephthalate and diethyl terephthalate, and hydroxyl groups are formed at the polymer terminal.

Examples of the sulfur-containing compound as the modifier include, but are not limited to, protected thiol compounds such as S-trimethylsilylthiopropyltrimethoxysilane and S-triethylsilylthiopropylmethyldiethylsilane, S-methylthiopropyltrimethoxysilane, S-ethylthiopropylmethyldiethoxysilane, N-diethyldithiocarbamate, phenylisothiocyanate, 1, 4-diisothiocyanate, hexamethylene diisothiocyanate and butyl isothiocyanate.

The modifying agent is preferably a compound having a silicon-containing functional group, which preferably has an alkoxysilyl group or a silanol group.

The alkoxysilyl group of the modifier, for example, tends to react with the active terminal of the conjugated diene polymer, to dissociate the lithium alkoxide, and to form a bond between the terminal of the conjugated diene polymer chain and silicon of the modifier residue. The value obtained by subtracting the number of SiOR reduced by the reaction from the total number of SiOR possessed by 1 molecule of the modifier is the number of alkoxysilyl groups possessed by the modifier residue. The aza-silacyclic group of the modifier forms a bond of > N-Li and a bond between the terminal of the conjugated diene polymer and silicon of the modifier residue. The > N — Li bond tends to be > NH or LiOH easily by the action of water or the like during finishing. In addition, in the modifier, the unreacted and remaining alkoxysilyl group tends to be easily changed to silanol (Si — OH group) by the action of water or the like during finishing.

In the modification step, when a modifier having 3 alkoxy groups per 1 silicon atom is used, that is, when 3 moles of active terminals of the conjugated diene polymer are reacted with 1 mole of trialkoxysilyl groups, the active terminals are reacted with at most 2 moles of the conjugated diene polymer, and 1 mole of alkoxy groups tend to remain unreacted. This was confirmed by that 1 mol of the conjugated diene polymer was not reacted and remained as an unreacted polymer. By reacting a large amount of alkoxy groups, the viscosity of the polymer tends to be prevented from being greatly changed due to a condensation reaction during finishing or storage. It is preferable to use a modifier having 1 alkoxysilyl group with respect to 1 silicon atom.

The modified conjugated diene polymer (a) and/or (B) obtained by the modification step preferably has a functional group represented by the general formula (1) at the polymerization initiation end and a functional group containing an alkoxysilyl group and an amine at the end different from the polymerization initiation end having the functional group represented by the general formula (1). This improves the balance between the hysteresis loss factor and the wet skid resistance.

Such modified conjugated diene polymers (a) and (B) can be obtained by appropriately selecting a polymerization initiator and a modifier.

Specifically, a polymer having an amino group at the polymerization initiation end and a functional group containing a silyl group and an amine at the termination end can be obtained by randomly polymerizing styrene and butadiene using a lithium amide polymerization initiator and adding a modifier having a functional group containing an alkoxysilyl group and an amine thereto to perform a reaction.

By having functional groups at both ends of the polymer, affinity and/or reactivity of the silica compounded in the resin composition for a tire with both ends of the polymer is improved, and improvement of dispersibility of the silica can be expected.

The reaction temperature in the modification step is preferably the same as the polymerization temperature of the conjugated diene polymer, and particularly preferably a temperature at which heating is not performed after the polymerization. More preferably 0 ℃ to 120 ℃ and even more preferably 50 ℃ to 100 ℃.

The reaction time in the modification step is preferably 10 seconds or longer, more preferably 30 seconds or longer.

The conjugated diene polymer and the modifier in the modification step may be mixed by any mixing method such as mechanical stirring and stirring with a static mixer. When the polymerization step is a continuous type, the modification step is also preferably a continuous type. As the reactor used in the reforming step, for example, a tank-type or tubular reactor with a stirrer is used. The modifier may be diluted with an inert solvent and continuously supplied to the reactor.

As the modifier, a compound represented by the following general formula (8) is preferable.

[ solution 9]

In the formula (8), R¹²～R¹⁴Each independently represents a single bond or an alkylene group having 1 to 20 carbon atoms, R¹⁵～R¹⁸And R²⁰Each independently represents an alkyl group having 1 to 20 carbon atoms, R¹⁹And R²²Each independently represents an alkylene group having 1 to 20 carbon atoms, R²¹Represents an alkyl group having 1 to 20 carbon atoms or a trialkylsilyl group.

m represents an integer of 1 to 3, and p represents 1 or 2.

R when plural number exists¹²～R²²M and p are each independently.

i represents an integer of 0 to 6, j represents an integer of 0 to 6, k represents an integer of 0 to 6, and (i + j + k) represents an integer of 1 to 10.

A represents a single bond, a hydrocarbon group having 1 to 20 carbon atoms, or an organic group having 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 having no active hydrogen.

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 which does not deactivate the active terminal of the conjugated diene polymer. The organic group is a compound having no hydroxyl group (-OH), a secondary amino group (- (II) (III))>NH), primary amino group (-NH)₂) And an organic group having a functional group of active hydrogen such as a sulfhydryl group (-SH). When (i + j + k) is 1, a may not be present.

In the formula (8), a preferably represents any one of the following general formulae (9) to (12).

[ solution 10]

In the above formula (9), B¹Represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, B¹In the case of plural number, B¹Each independently.

[ solution 11]

In the formula (10), B²Represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, B³Represents an alkyl group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, B²And B³In the case of plural numbers, respectively, B²And B³Each independently.

[ solution 12]

In the formula (11), B⁴Represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, B⁴In the case of plural number, B⁴Each independently.

[ solution 13]

In the formula (12), B⁵Represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, a represents an integer of 1 to 10, B⁵In the case of plural number, B⁵Each independently.

When a in the formula (8) represents any one of the formulae (9) to (12), a modified conjugated diene polymer having more excellent performance tends to be obtained.

As the modifier of the formula (8), examples of the modifier having (i + j + k) of 1 to 2 include, but are not limited to, a modifier which overlaps with the modifier, such as 3-dimethoxymethylsilylpropyldimethylamine (1-functional), 3-trimethoxysilylpropyldimethylamine (2-functional), bis (3-trimethoxysilylpropyl) methylamine (4-functional), bis (3-dimethoxymethylsilylpropyl) methylamine (2-functional), (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] ethylamine (4-functional), and [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - (3-trimethoxysilylpropyl) methylamine (4-functional) Functional), bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] methylamine (4 functional), bis (3-triethoxysilylpropyl) ethylamine (4 functional), 1- (3-triethoxysilylpropyl) -2, 2-diethoxy-1-aza-2-silacyclopentane (4 functional), 1- (3-dimethoxymethylsilylpropyl) -2, 2-dimethoxy-1-aza-2-silacyclopentane (3 functional), [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - (3-diethoxyethylsilylpropyl) methylamine (3 functional), Bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] methylamine (4-functional), (3-trimethoxysilylpropyl) - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -methylamine (3-functional).

Hereinafter, as the modifier in the case where a in the above formula (8) is represented by the formula (9), with respect to the modifier having (i + j + k) of 3 or more, which is a polyfunctional compound, there may be mentioned, but not limited to: 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-trimethoxysilylpropyl) amine, bis (2-methoxy-1-aza-2-silacyclopentane) propyl ] amine, bis (3-trimethoxysilylpropyl) amine, bis (3-methoxy-1-aza-2-silacyclopentane) propyl) amine, bis (3-propyl) amine, bis (2-methoxy-silacyclopentane) amine, bis (2-propyl) amine, bis (trimethoxysilylpropyl) amine, bis (2-amino, bis (trimethoxysilylpropyl) amine, bis (2-amino) propyl) amine, bis (2-amino) amide, bis (methoxy-amino) propyl) amide, tris (methoxy-phenyl) amide, tris (2-phenyl) amide, tris (ethyl) amide, tris (2, tris, bis (2, tris, 2, tris, or (tris, 6, or (tris, 6, bis (tris, 6, 2,6, 2, bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - (3-triethoxysilylpropyl) amine, tris [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] amine, tetrakis (3-trimethoxysilylpropyl) -1, 3-propanediamine, tris (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, bis (3-trimethoxysilylpropyl) -bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, tris [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - (3-trimethoxysilylpropyl) -1, 3-propanediamine, tetrakis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, tris (3-trimethoxysilylpropyl) - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, bis (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - (3-trimethoxysilylpropyl) - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, tris [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] ] -1, 3-propanediamine, tetrakis (3-triethoxysilylpropyl) -1, 3-propanediamine, tris (3-triethoxysilylpropyl) - [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, bis (3-triethoxysilylpropyl) -bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, tris [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - (3-triethoxysilylpropyl) -1, 3-propanediamine, tetrakis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine, tris (3-triethoxysilylpropyl) - [3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, bis (3-triethoxysilylpropyl) - [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - [3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - (3-triethoxysilylpropyl) - [3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, tris [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - [3- (1-ethoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -1, 3-propanediamine, tetrakis (3-trimethoxysilylpropyl) -1, 3-bisaminomethylcyclohexane, tris (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, bis (3-trimethoxysilylpropyl) -bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-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, bis (3-methoxy-1-aza-2-azacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, bis (3-methoxy-2-aza-2-sila-2-azacyclopentane) propyl ester, bis (3-methoxy-1-methoxy-2-azacyclopentane) propyl ester, bis (3-methoxy-1-sila-2-azacyclopentane) propyl ester, bis (3-methyl) propyl ester, tris (3-amino-methyl) methyl ester, tris (2-methyl) ethyl ester, tris (meth) amide, bis (2-amino) methyl ester, tris (meth) methyl ester, bis (2-amino) methyl ester, and (meth) methyl ester, Tetrakis (3-triethoxysilylpropyl) -1, 3-propanediamine, tris (3-triethoxysilylpropyl) - [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, bis (3-triethoxysilylpropyl) -bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, tris [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl ] - (3-triethoxysilylpropyl) -1, 3-propanediamine, tri (3-triethoxysilylpropyl) -1, 3-propanediamine, and mixtures thereof, 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, bis (3-ethoxysilylpropyl) - [1- (2-ethoxy-2-sila-2-azacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, bis (3-triethoxy-1-aza-2-sila-2-azacyclopentane) propyl ] -1, 3-bisaminomethylcyclohexane, bis (3-ethoxysilylpropyl) - [3- (2-ethoxysilylpropyl) -2-azacyclopentane, bis (3-ethyl) propyl ] -1, 3-sila-2-azacyclopentane, and (3-ethyl-2-sila-cyclopentane), Tetrakis (3-trimethoxysilylpropyl) -1, 6-hexanediamine, pentakis (3-trimethoxysilylpropyl) -diethylenetriamine.

Examples of the modifier in the case where a in the formula (8) is represented by the formula (10) include, but are not limited to: tris (3-trimethoxysilylpropyl) -methyl-1, 3-propanediamine, bis (2-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl]-methyl-1, 3-propanediamine, bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl]- (3-trimethoxysilylpropyl) -methyl-1, 3-propanediamine, tris (3-triethoxysilylpropyl) -methyl-1, 3-propanediamine, bis (2-triethoxysilylpropyl) - [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl]-methyl-1, 3-propanediamine, bis [3- (2, 2-diethoxy-1-aza-2-silacyclopentane) propyl]- (3-triethoxysilylpropyl) -methyl-1, 3-propanediamine, N¹,N^1’- (propane-1, 3-diyl) bis (N)¹-methyl-N³,N³Bis (3- (trimethoxysilyl) propyl) -1, 3-propanediamine), N¹- (3- (bis (3- (trimethoxysilyl) propyl) amino) propyl) -N¹-methyl-N³- (3- (methyl (3- (trimethoxysilyl) propyl) amino) propyl) -N³- (3- (trimethoxysilyl) propyl) -1, 3-propanediamine.

Examples of the modifier in the case where A in the formula (8) is represented by the formula (11) include, but are not limited to, tetrakis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, tris [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - (3-trimethoxysilylpropyl) silane, tris [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] silane, bis (3-trimethoxysilylpropyl) -bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, (3-trimethoxysilyl) - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) -bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, bis [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) -bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, tris (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, bis (3-trimethoxysilylpropyl) - [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] silane, bis [3- (1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane) propyl ] -bis (3-trimethoxysilylpropyl) silane, bis (3-trimethoxysilylpropyl) -bis [3- (1-methoxy-2-methyl-1-sila-2- Azacyclopentane) propyl ] silane.

Examples of the modifier in the case where A in the formula (8) is represented by the formula (12) include, but are not limited to, 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.

Examples of the modifier in the case where a in the formula (8) represents an organic group having an oxygen atom and no active hydrogen include, but are not limited to, (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] ether (4-functional), 3,4, 5-tris (3-trimethoxysilylpropyl) -cyclohexyl- [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] ether (8-functional).

Examples of the modifier in the case where a in the formula (8) represents an organic group having a phosphorus atom and no active hydrogen include, but are not limited to, (3-trimethoxysilylpropyl) phosphate, bis (3-trimethoxysilylpropyl) - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] phosphate, bis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] - (3-trimethoxysilylpropyl) phosphate, and tris [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] phosphate.

In the formula (8), a preferably represents the formula (9) or the formula (10), and k preferably represents 0. This tends to be a modifier which is easily obtainable, and the modified conjugated diene polymer tends to be more excellent in the wear resistance and the low hysteresis loss performance after being converted into a vulcanizate.

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-silacyclopentane) propyl ] -1, 3-propanediamine, tetrakis (3-trimethoxysilylpropyl) -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-trimethoxysilylpropyl) -methyl-1, 3-propanediamine.

In the formula (8), A more preferably represents a formula (9) or a formula (10), k represents 0, and a in the formula (9) or the formula (10) represents an integer of 2 to 10. By using such a modifier, the wear resistance and the low hysteresis loss performance tend to be more excellent after the production of the sulfide.

Examples of such a modifier include, but are not limited to, tetrakis [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl group]1, 3-propanediamine, tetrakis (3-trimethoxysilylpropyl) -1, 3-bisaminomethylcyclohexane, N¹- (3- (bis (3- (trimethoxysilyl) propyl) amino) propyl) -N¹-methyl-N³- (3- (methyl (3- (trimethoxysilyl) propyl) amino) propyl) -N³- (3- (trimethoxysilyl) propyl) -1, 3-propanediamine.

The amount of the compound represented by formula (8) as the modifier to be added can be adjusted so that the reaction proceeds in a desired stoichiometric ratio by adjusting the number of moles of the polymerization initiator relative to the number of moles of the modifier, thereby achieving a desired degree of branching. The specific mole number of the polymerization initiator is preferably 1.0-fold mole or more, more preferably 2.0-fold mole or more, based on the mole number of the modifier. In this case, in formula (8), the number of functional groups of the modifier ((m-1). times.i + p.times.j + k) is preferably an integer of 1 to 10, more preferably an integer of 2 to 10.

< hydrogenation step >

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 be hydrogenated in their respective conjugated diene portions.

The method for hydrogenating the conjugated diene portion is not particularly limited, and a known method can be used.

A suitable hydrogenation method is a method in which hydrogenation is carried out by blowing gaseous hydrogen into a polymer solution in the presence of a catalyst.

Examples of the catalyst include heterogeneous catalysts such as a catalyst in which a noble metal is supported on a porous inorganic substance; a catalyst obtained by solubilizing a salt such as nickel or cobalt and reacting the solubilized salt with an organoaluminum or the like, or a homogeneous catalyst using a metallocene such as titanocene. Among these, a titanocene catalyst is preferable in that mild hydrogenation conditions can be selected. In addition, hydrogenation of aromatic groups can be carried out by using a supported catalyst of a noble metal.

Examples of the hydrogenation catalyst include, but are not limited to: (1) a supported heterogeneous hydrogenation catalyst in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called ziegler-type hydrogenation catalysts using organic acid salts such as Ni, Co, Fe, and Cr, transition metal salts such as acetylacetone salts, and reducing agents such as organic aluminum; (3) and so-called organometallic complexes such as organometallic compounds of Ti, Ru, Rh, Zr, etc.

Further, as the hydrogenation catalyst, there may be mentioned, for example, known hydrogenation catalysts described in Japanese patent publication No. 42-8704, Japanese patent publication No. 43-6636, Japanese patent publication No. 63-4841, Japanese patent publication No. 1-37970, Japanese patent publication No. 1-53851, Japanese patent publication No. 2-9041, and Japanese patent application laid-open No. 8-109219. As a preferred hydrogenation catalyst, a reaction mixture of a titanocene compound and a reducing organometallic compound can be cited.

In the production steps of the modified conjugated diene polymers (a) and (B), a deactivator, a neutralizer, or the like may be added to the modified conjugated diene polymer solution after the modification step, as necessary.

Examples of the deactivator include, but are not limited to, water; alcohols such as methanol, ethanol, and isopropanol.

Examples of the neutralizing agent include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and neodecanoic acid (a multi-branched carboxylic acid mixture having 9 to 11 carbon atoms and 10 carbon atoms as the center); aqueous solution of inorganic acid, carbon dioxide.

From the viewpoint of preventing gel formation after polymerization and from the viewpoint of improving stability during processing, it is preferable to add a rubber stabilizer to the modified conjugated diene polymers (a) and (B).

As the rubber stabilizer, known ones can be used, and examples thereof include, but are not limited to, antioxidants such as 2, 6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3- (4 ' -hydroxy-3 ', 5 ' -di-tert-butylphenol) propionate, and 2-methyl-4, 6-bis [ (octylthio) methyl ] phenol.

In order to further improve the processability of the modified conjugated diene polymers (a) and (B), extender oil may be added to the modified conjugated diene copolymer as necessary.

As a method of adding the extender oil to the modified conjugated diene polymers (a) and (B), the following methods are preferable, but not limited to: extender oil is added to the polymer solution and mixed to produce an oil-extended copolymer solution, which is then desolventized.

Examples of the timing of adding the extender oil include, but are not limited to, the following timings: after the modification step, before the polymer solutions are mixed, or after the two polymer solutions are mixed.

When the extender oil is mixed, the viscosity of the polymer solution is lowered, and from the viewpoint of easy mixing of the polymer solutions, it is preferable to add the extender oil after the modification step and before mixing of both the polymer solutions.

Examples of the extender oil include aromatic oil, naphthenic oil, and paraffin oil. Among these, in terms of environmental safety and in terms of prevention of oil exudation and wet grip properties, a substituted aromatic oil having a polycyclic aromatic (PCA) component of 3 mass% or less by the IP346 method is preferable. Examples of the oil include oils derived from vegetable oils, such as "Vivamax 5000" and "Vivamax 5100" manufactured by H & R corporation.

As alternative perfume oils, there may be mentioned TDAE (Treated distilled Aromatic Extracts), MES (Mild Extraction solvent), etc., shown in Kautschuk Gummi Kunststoffe 52(12)799(1999), and RAE (Residual Aromatic Extracts).

The amount of the extender oil to be added is not particularly limited, and is preferably 10 parts by mass or more and 60 parts by mass or less, and more preferably 20 parts by mass or more and 37.5 parts by mass or less, per 100 parts by mass of the modified conjugated diene polymer.

< mixing step >

In the method for producing a modified conjugated diene polymer mixture according to the present embodiment, as described above, the polymer solutions of the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) are obtained through the polymerization step and the modification step, and then the polymer solutions are mixed and the solvent is removed to obtain the modified conjugated diene polymer mixture (C).

In the mixing step, it is preferable to provide a storage tank for storing the polymer solution distilled from each reaction tank, downstream of each of the reaction tank for the modified conjugated diene polymer (a) and the reaction tank for the modified conjugated diene polymer (B). By providing the storage tanks for the respective polymers, the flow rate can be adjusted after the modification step and before the mixing step, the mixing ratio of the polymer solution can be easily finely adjusted, and the polymer solution can be stored in a tank separate from the reaction tank.

More preferably, the storage tank has a capacity larger than that of the reaction tank.

Examples of the mixing means of the present embodiment include, but are not limited to, a method using a tank equipped with a rotary stirrer, and a method using a pipe equipped with a rotary stirrer or a static mixer. From the viewpoint of stirring ability, a tank equipped with a rotary stirrer is preferably used, and from the viewpoint of production efficiency, a pipe equipped with a rotary stirrer or a static mixer is preferably used.

The temperature in the mixing step is not particularly limited, but is preferably 0 ℃ to 120 ℃ and more preferably 50 ℃ to 100 ℃. This is because the viscosity of the polymer solution decreases and mixing becomes easy when the temperature is high. In a preferred embodiment, the solution distilled off from the overhead portion of the polymerization reaction tank is once stored and then mixed, but if the storage time is short, the temperature of the solution can be maintained even after the solution is distilled off from the polymerization reactor, and heating is not necessary in the mixing step; the storage tank, the mixing tank, the piping, and the like may be kept warm or heated under conditions where the temperature of the solution is likely to decrease, such as when the storage time is long or when the temperature is low.

The mixing mass ratio of the modified conjugated diene polymer (a) to 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, and yet more preferably 75/25 to 60/40.

When the mixing mass ratio is within this range, the balance between the wear resistance after producing the vulcanizate and the workability at the time of producing the vulcanizate tends to be excellent.

The above-mentioned ratio is a mass ratio of the modified conjugated diene polymer, and when the concentrations of the polymer solution of the modified conjugated diene polymer (a) and the polymer solution of the modified conjugated diene polymer (B) are the same, the mass ratio of the solutions may be used as it is, but the concentrations of these solutions may be different. This is because, in the case of producing a polymer having a small molecular weight, the reaction heat is easily increased by increasing the amount of the polymerization initiator to be added, and therefore, the concentration of the solution may be decreased in order to maintain the polymerization temperature. In this case, it is preferable to adjust the mixing ratio in consideration of the solution concentration so as to achieve a preferable mass ratio of the polymer.

In the solvent removal step, known methods such as drying and devolatilization can be used. Examples of the method include: a method in which a polymer is filtered out after separating a solvent by steam stripping or the like, and is further dehydrated and dried to obtain a polymer; a method of concentrating with a flash tank and further devolatilizing with an exhaust extruder or the like; a method of directly performing devolatilization using a rotary dryer or the like.

[ Properties ]

(molecular weight)

The modified conjugated diene polymer (A) had a weight average molecular weight (Mw) of 70X 10⁴300X 10 above⁴Hereinafter, preferably 70X 10⁴Above 200 × 10⁴Hereinafter, more preferably 100 × 10⁴Above 180 × 10⁴The following. From the viewpoint of abrasion resistance after production of a vulcanizate, 70X 10⁴As described above, the balance between the wear resistance after production of the vulcanizate and the processability in the production of the vulcanizate is 300X 10⁴Hereinafter, preferably 180X 10⁴The following.

The modified conjugated diene polymer (B) had a weight average molecular weight (Mw) of 10X 10⁴Above and less than 70 × 10⁴Preferably 15X 10⁴Above 60 × 10⁴Hereinafter, more preferably 30 × 10⁴Above 55 × 10⁴The following. 10X 10 in terms of abrasion resistance after production of a vulcanizate⁴Above all, from the viewpoint of the balance between the wear resistance after production of the vulcanizate and the processability in the production of the vulcanizate, it is less than 70X 10⁴Preferably 55X 10⁴The following.

Generally, a large molecular weight provides excellent wear resistance, but poor processability. On the other hand, when the molecular weight is small, the processability is excellent, but the wear resistance is poor.

The weight average molecular weight (Mw) is 70X 10⁴300X 10 above⁴The modified conjugated diene polymer (a) has a large molecular weight and excellent wear resistance, but tends to have poor processability. On the other hand, the weight average molecular weight (Mw) was 10X 10⁴Above and less than 70 × 10⁴The modified conjugated diene polymer (B) has a low molecular weight, but tends to have poor abrasion resistance. But do notThus, by mixing both, the modified conjugated diene polymer mixture (C) having the respective advantages, that is, excellent balance between abrasion resistance and processability tends to be obtained.

The weight-average molecular weight of the modified conjugated diene polymer mixture (C) was 70X 10⁴300X 10 above⁴Hereinafter, preferably 85 × 10⁴Above 200 × 10⁴Hereinafter, more preferably 100 × 10⁴Above 180 × 10⁴The following. It is preferably 70X 10 in terms of abrasion resistance after production into a vulcanizate⁴From the viewpoint of the balance between the wear resistance after production of the vulcanizate and the processability in the production of the vulcanizate, the above ratio is preferably 180 × 10⁴The following.

The difference Δ Mw between the weight average molecular weights of the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) of the present embodiment is preferably 50 × 10⁴Above, more preferably 60 × 10⁴More preferably 70 × 10 or more⁴Above, and more preferably 80 × 10⁴The above.

When the difference between the weight average molecular weights is within this range, the balance between the wear resistance after production of the vulcanizate and the processability during production of the vulcanizate tends to be excellent.

The wear resistance tends to be more excellent as the molecular weight is larger, and the processability tends to be more excellent as the molecular weight is smaller.

The difference in weight average molecular weight between the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) means that the modified conjugated diene polymer (a) is a modified conjugated diene polymer that focuses more on abrasion resistance, and the modified conjugated diene polymer (B) is a modified conjugated diene polymer that focuses more on processability.

Thus, the complementary interaction when the two are mixed tends to increase.

The weight average molecular weights (Mw) of the modified conjugated diene polymers (a) and (B) can be controlled by adjusting the polymerization temperature, the amount of monomer added, the amount of polymerization initiator added in each polymerization step, and the like.

When the polymerization temperature in the polymerization step is increased, the polymerization reaction rate becomes high, and a polymer having a large weight average molecular weight tends to be obtained. However, if the polymerization temperature is too high, the polymer ends are deactivated by heat, and the modification reaction does not proceed, and the weight average molecular weight of the modified conjugated diene polymer tends not to increase easily.

When the amount of the monomer added in the polymerization step is increased, the amount of the monomer to be polymerized is increased relative to 1 molecule of the polymerization initiator, and thus the weight average molecular weight tends to be increased.

When the amount of the polymerization initiator added in the polymerization step is increased, the amount of the monomer to be polymerized is decreased relative to 1 molecule of the polymerization initiator, and thus the weight average molecular weight tends to be decreased.

Thus, the weight average molecular weight difference (Δ Mw) between the modified conjugated diene polymers (a) and (B) can be controlled to the above numerical range by appropriately adjusting the conditions of the modified conjugated diene polymer (a) and/or the modified conjugated diene polymer (B) in the polymerization step.

(molecular weight distribution)

The modified conjugated diene polymer mixture (C) has a molecular weight distribution (Mw/Mn) of 1.8 to 4.5. Preferably 1.85 to 4.0, more preferably 1.90 to 3.50.

When the molecular weight distribution (Mw/Mn) is within this range, the balance between the wear resistance after production of the vulcanizate and the processability during production of the vulcanizate tends to be excellent.

The molecular weight distribution of the modified conjugated diene polymer mixture (C) can be controlled within the above numerical range by adjusting the molecular weight difference, the molecular weight distribution, and the composition ratio of the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B).

(modification ratio)

The modification ratio of the modified conjugated diene polymer mixture (C) is preferably 50% by mass or more, more preferably 60% by mass or more, further preferably 70% by mass or more, and further more preferably 80% by mass or more, relative to the total amount of the conjugated diene polymers. When the modification ratio is within the above range, the processability in producing a sulfide tends to be excellent, and the balance between the hysteresis loss resistance and the wet skid resistance after producing a sulfide tends to be excellent.

The modification ratio of the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) is preferably 50% by mass or more, more preferably 65% by mass or more, and even more preferably 80% by mass or more, relative to the total amount of the conjugated diene polymers.

When the modification ratio is within this range, the processability in producing a sulfide tends to be excellent, and the balance between the hysteresis loss resistance and the wet skid resistance after producing a sulfide tends to be excellent. The modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) are both preferably high in modification ratio.

When a modified conjugated diene polymer having a large molecular weight is compared with a modified conjugated diene polymer having a small molecular weight, the modified conjugated diene polymer having a small molecular weight tends to have an excellent balance between low hysteresis loss properties and wet skid resistance after production of a vulcanizate. Therefore, when only one of the modified conjugated diene polymer (a) and the modified conjugated diene polymer (B) has a high modification ratio, the modification ratio of the modified conjugated diene polymer (B) is preferably high.

The modification ratio of the modified conjugated diene polymer mixture (C) and the modified conjugated diene polymers (a) and (B) can be controlled to the above numerical range, for example, by the purity of the monomer or solvent used for polymerization, the amount of the modifier added, the temperature in the modification step, and the like.

(shrinkage factor)

The shrinkage factor (g') measured by GPC-light scattering measurement with a viscosity detector (hereinafter also referred to simply as "GPC-light scattering measurement with a viscosity detector" or "3D-GPC measurement") 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 polymer (for example, the number of branches of the star polymer (also referred to as "the number of arms of the star polymer")) tends to increase.

When modified conjugated diene polymers having the same molecular weight are compared, the shrinkage factor (g ') decreases as the number of branches of the modified conjugated diene polymers increases, and thus the shrinkage factor (g') in this case can be used as an index of the degree of branching.

The shrinkage factor (g') was measured by 3D-GPC measurement.

The relation between intrinsic viscosity and molecular weight ([ eta. ])]＝KMα([η]: intrinsic viscosity, M: molecular weight) was set to logK-3.883 and α -0.771, and a standard intrinsic viscosity [. eta. ] was prepared]₀Graph relating to molecular weight M.

As intrinsic viscosity [ eta ]]Relative to the standard intrinsic viscosity [. eta. ]]₀At each molecular weight M, the intrinsic viscosity [ eta ] of the sample at each molecular weight M measured by 3D-GPC was calculated]Relative to the standard intrinsic viscosity [. eta. ]]₀Eta of]/[η]₀The average value thereof was taken as the shrinkage factor (g').

More specifically, the measurement can be carried out by the method described in the examples below.

In the modified conjugated diene polymer (a) and/or the modified conjugated diene polymer (B), a preferable embodiment is one in which the shrinkage factor (g') measured by 3D-GPC is 0.70 to 1.0.

When the shrinkage factor (g') of the modified conjugated diene polymer (a) and/or (B) is in the above range, the strength at high temperature tends to be excellent.

The shrinkage factor (g ') is an index of the branched structure of the modified conjugated diene copolymer, and a modified conjugated diene polymer having a shrinkage factor (g') of 0.70 to 1.0 tends to be a modified conjugated diene polymer having 4 or less branches in 1 molecule of the modified diene polymer. In this case, the shrinkage factor (g') is more preferably 0.73 to 0.99, and still more preferably 0.75 to 0.98.

In order to obtain a modified conjugated diene copolymer having a shrinkage factor (g') within the above range, for example, the following method is effective: the modifier having 4 or less reaction sites with the active end is added in a molar amount of at least one-fourth of the total molar amount of the polymerization initiator to obtain a modified conjugated diene copolymer having 4 or less branches.

The strength at high temperature tends to be excellent as the molecular weight increases, if the strength is the same branched structure, and therefore the shrinkage factor (g') of the modified conjugated diene polymer (a) having a large molecular weight is preferably 0.70 to 1.0.

The shrinkage factor (g') of the modified conjugated diene polymer (a) and/or (B) measured by 3D-GPC is more preferably 0.30 or more and less than 0.70.

The composition containing such a modified conjugated diene polymer and a filler has a further reduced viscosity and is excellent in processability.

The shrinkage factor (g ') is an index of the branched structure of the modified conjugated diene copolymer, and a modified conjugated diene polymer having a shrinkage factor (g') of 0.30 or more and less than 0.70 is preferred to be a modified conjugated diene polymer having 5 or more branches in the number of branches in 1 molecule of the modified diene polymer.

In order to obtain a modified conjugated diene copolymer having a shrinkage factor (g') within the above range, for example, the following method is effective: the modifier having 5 or more reaction sites with the active end is added in a mole number of one fifth or less based on the total mole number of the polymerization initiator to obtain a modified conjugated diene copolymer having 5 or more branches.

The modified conjugated diene polymer having a shrinkage factor (g ') of 0.30 or more and less than 0.64 tends to be 6-branched or more, and the modified conjugated diene polymer having a shrinkage factor (g') of 0.30 or more and less than 0.59 tends to be 8-branched or more. The composition containing such a modified conjugated diene polymer and a filler has a further reduced viscosity and further excellent processability.

In the processability, since the smaller the molecular weight, the more excellent the processability tends to be if the molecular weight is the same, the shrinkage factor (g') of the modified conjugated diene polymer (B) having a small molecular weight is preferably 0.30 or more and less than 0.70, more preferably 0.30 or more and less than 0.64, and still more preferably 0.30 or more and less than 0.59.

The shrinkage factor (g ') of the modified conjugated diene polymer (A) as measured by 3D-GPC is preferably 0.70 to 1.0, and the shrinkage factor (g') of the modified conjugated diene polymer (B) as measured by 3D-GPC is preferably 0.30 to less than 0.70. When the shrinkage factor (g') is in such a range, a modified conjugated diene polymer mixture having an excellent balance between high-temperature strength and processability tends to be obtained.

(Nitrogen content)

In the production method of the present embodiment, the nitrogen content of the modified conjugated diene polymer (B) is preferably 3 to 70 mass ppm.

When the nitrogen content is 3 ppm by mass or more, the effect of improving the balance between the hysteresis loss resistance and the wet skid resistance in producing a sulfide can be obtained; when the amount is 70 mass ppm or less, the effect of suppressing the decrease in rigidity due to excessive dispersion of silica after the formulation is obtained.

The nitrogen content is more preferably 6 mass ppm to 60 mass ppm, 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 proportion of nitrogen contained in the modifier, the amount of the nitrogen-containing modifier added, and the amount of the modifier bonded to the polymerization terminal.

[ Polymer composition ]

The modified conjugated diene polymer mixture obtained by the method for producing a modified conjugated diene polymer mixture according to the present embodiment can be combined with another material to produce 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).

Examples of the polymer other than the modified conjugated diene polymer mixture (C) include a rubbery polymer having a structure other than the structures of the modified conjugated diene polymers (a) and (B) (hereinafter referred to as "other rubbery polymer") and a resinous polymer.

Examples of the other rubbery polymer include, but are not limited to, a conjugated diene polymer or a hydrogenated product thereof, a random copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof, a block copolymer of a conjugated diene compound and a vinyl aromatic compound or a hydrogenated product thereof, a non-diene polymer, and natural rubber. Specific examples of the other rubbery polymer include, but are not limited to, styrene-based elastomers such as butadiene rubber or a hydrogenated product thereof, isoprene rubber or a hydrogenated product thereof, styrene-butadiene rubber or a hydrogenated product thereof, a styrene-butadiene block copolymer or a hydrogenated product thereof, a styrene-isoprene block copolymer or a hydrogenated product thereof, and nitrile rubber or a hydrogenated product thereof.

Examples of the non-diene polymer include, but are not limited to, olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, bromobutyl rubber, acrylic rubber, fluorine rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β -unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.

Examples of the natural rubber include, but are not limited to, RSS 3-5, SMR, and epoxidized natural rubber, which are smoke film adhesives.

Examples of the method of 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) include a method of mixing a solution of the modified conjugated diene polymer mixture (C) with a solution of another polymer, and a method of mechanically mixing the modified conjugated diene polymer mixture (C) with another polymer.

The other polymer may be a modified rubber to which a functional group having polarity such as a hydroxyl group or an amino group is added. In the case of use for tire applications, butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, butyl rubber are preferably used.

When the other polymer is the above-mentioned "other rubbery polymer", the weight average molecular weight thereof is preferably 2,000 to 2,000,000, more preferably 5,000 to 1,500,000, from the viewpoint of balance between performance and processability. In addition, a rubber-like polymer having a low molecular weight, so-called liquid rubber, may be used. These other rubbery polymers may be used alone 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 (mass ratio) of the modified conjugated diene polymer mixture (C) to the other rubbery polymer is preferably 10/90 or more and 100/0 or less, more preferably 20/80 or more and 90/10 or less, and further preferably 50/50 or more and 80/20 or less, in terms of (modified conjugated diene polymer mixture (C)/other rubbery polymer).

Therefore, in the polymer composition, the modified conjugated diene polymer mixture (C) is contained in an amount of preferably 10 parts by mass or more and 100 parts by mass or less, more preferably 20 parts by mass or more and 90 parts by mass or less, and still more preferably 50 parts by mass or more and 80 parts by mass or less, based on the total amount (100 parts by mass) of the polymer composition.

When the content ratio of (modified conjugated diene polymer mixture (C)/other rubbery polymer) is in the above range, the vulcanizate produced has an excellent balance between hysteresis loss resistance and wet skid resistance, and also satisfies abrasion resistance and breaking strength.

The modified conjugated diene polymer mixture (C) is suitably used in the form of a sulfide. Examples of the vulcanizate include tires, hoses, shoe soles, vibration-proof rubbers, automobile parts, vibration-free rubbers, and resin-reinforcing rubbers such as high impact polystyrene and ABS resins. The modified conjugated diene polymer is particularly suitable for use in a composition for a tread rubber for a tire. The sulfide can be obtained, for example, as follows: the modified conjugated diene polymer mixture (C) is kneaded with, if necessary, a silica-based inorganic filler, an inorganic filler such as carbon black, a rubber-like polymer other than the modified conjugated diene polymer mixture (C), a silane coupling agent, a rubber softener, a vulcanizing agent, a vulcanization accelerator, a vulcanization aid, and the like to prepare a rubber composition, and then heated and vulcanized to obtain a vulcanizate.

[ rubber composition ]

The modified conjugated diene polymer mixture obtained by the production method of the present embodiment can be used for a rubber composition.

The rubber composition preferably contains 100 parts by mass of a rubbery 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.

The filler preferably contains a silica-based inorganic filler.

In the rubber composition, the silica-based inorganic filler is dispersed, so that the processability in producing a vulcanizate tends to be more excellent, the balance between the hysteresis loss resistance and the wet skid resistance after producing a vulcanizate tends to be more excellent, and the breaking strength and the abrasion resistance tend to be more excellent.

When the rubber composition is used for automobile parts such as tires and vibration-proof rubbers, and vulcanized rubber such as shoes, the rubber composition preferably further contains a silica-based inorganic filler.

Examples of the filler include, but are not limited to, silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. These may be used alone or in combination of two or more.

The content of the filler in the rubber composition is preferably 5.0 parts by mass or more and 150 parts by mass or less, more preferably 10 parts by mass or more and 120 parts by mass or less, and still more preferably 20 parts by mass or more and 100 parts by mass or less, with respect to 100 parts by mass of the rubber-like polymer comprising the modified conjugated diene polymer mixture (C).

The content of the filler is preferably 5.0 parts by mass or more in view of exhibiting the effect of adding the filler, and is preferably 150 parts by mass or less in view of sufficiently dispersing the filler and practically satisfying the processability and mechanical strength of the rubber composition.

The silica-based inorganic filler is not particularly limited, and a known one can be used, and preferably contains SiO as a constituent unit₂Or Si₃Solid particles of Al, more preferably SiO as a main component of the structural unit₂Or Si₃Solid particles of Al. The main component herein means a component contained in the silica-based inorganic filler by 50 mass% or more, preferably 70 mass% or more, and more preferably 80 mass% or more.

Examples of the silica-based inorganic filler include, but are not limited to, inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber. Further, there may be mentioned a silica-based inorganic filler having a surface hydrophobized, and a mixture of a silica-based inorganic filler and an inorganic filler other than silica. Among these, silica and glass fibers are preferable, and silica is more preferable, from the viewpoint of strength, abrasion resistance and the like. Examples of the silica include dry silica, wet silica, and synthetic silicate silica. Among these silicas, wet silica is preferred because of its excellent balance between the effect of improving the fracture characteristics and the 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 preferably 100m in view of obtaining practically excellent wear resistance and fracture characteristics²300m above g²A ratio of 170m or less²More than 250 m/g²The ratio of the carbon atoms to the carbon atoms is less than g.

In addition, the specific surface area may be relatively small (for example, less than 200 m) as required²The silica-based inorganic filler has a relatively large specific surface area (e.g., 200 m)²/g or more) of a silica-based inorganic filler.

Especially when the specific surface area is relatively large (e.g. 200 m)²/g or more), the modified conjugated diene polymer has an effect of improving the dispersibility of silica, particularly improving the abrasion resistance, and has a function of improving the abrasion resistanceThe good fracture characteristics and the low hysteresis loss factor tend to be well balanced.

The content of the silica-based inorganic filler in the rubber composition is preferably 5.0 parts by mass or more and 150 parts by mass or less, and more preferably 20 parts by mass or more and 100 parts by mass or less, with respect to 100 parts by mass of the rubber-like polymer comprising the modified conjugated diene-based polymer mixture (C). The content of the silica-based inorganic filler is preferably 5.0 parts by mass or more from the viewpoint of exhibiting the effect of adding the inorganic filler, and is preferably 150 parts by mass or less from the viewpoint of sufficiently dispersing the inorganic filler and practically satisfying the processability and mechanical strength of the rubber composition.

Examples of the carbon black include, but are not limited to, various grades of carbon black such as SRF, FEF, HAF, ISAF, and SAF. Of these, the nitrogen adsorption specific surface area is preferably 50m²A carbon black having a dibutyl phthalate (DBP) oil absorption of 80mL/100g or less.

The content of the carbon black is preferably 0.5 to 100 parts by mass, more preferably 3.0 to 100 parts by mass, and still more preferably 5.0 to 50 parts by mass, based on 100 parts by mass of the rubber-like polymer comprising the modified conjugated diene polymer mixture (C). The content of carbon black is preferably 0.5 parts by mass or more in view of exhibiting properties required for applications such as tires, such as dry grip performance and conductivity, and is preferably 100 parts by mass or less in view of dispersibility.

The metal oxide is a solid particle having a chemical formula MxOy (M represents a metal atom, and x and y each independently represent an integer of 1 to 6) as a main component of a structural unit. Examples of the metal oxide include, but are not limited to, aluminum oxide, titanium oxide, magnesium oxide, and zinc oxide.

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

The rubber composition may contain a silane coupling agent.

The silane coupling agent has a function of making the interaction between the rubbery polymer and the inorganic filler tight, and has groups having affinity or bonding properties with respect to the rubbery polymer and the silica-based inorganic filler, respectively, and is preferably a compound having a sulfur-bonding portion and an alkoxysilyl or silanol portion in one molecule. Examples of such compounds include bis [3- (triethoxysilyl) -propyl ] -tetrasulfide, bis- [3- (triethoxysilyl) -propyl ] -disulfide, and bis- [2- (triethoxysilyl) -ethyl ] -tetrasulfide.

The content of the silane coupling agent is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 20 parts by mass, and still more preferably 1.0 to 15 parts by mass, based on 100 parts by mass of the inorganic filler. 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 remarkable.

The rubber composition may contain a rubber softener in order to improve the processability thereof.

As the softener for rubber, mineral oil or a liquid or low molecular weight synthetic softener is suitable. A softening agent for mineral oil-based rubber, which is called process oil or extender oil and is used for softening, extending and improving the processability of rubber, is a mixture of aromatic rings, naphthenic rings and paraffinic chains, a substance having 50% or more of the total carbon atoms of paraffinic chains is called paraffinic, a substance having 30% or more to 45% or less of the total carbon atoms of naphthenic rings is called naphthenic, and a substance having more than 30% of the total carbon atoms of aromatic rings is called aromatic.

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, the softening agent for rubber used preferably has a moderate aromatic compound content because the softening agent for rubber tends to have good fusibility with the copolymer.

The content of the rubber softener is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass, and still more preferably 30 to 90 parts by mass, based on 100 parts by mass of the rubber-like polymer containing the modified conjugated diene polymer mixture (C). When the content of the rubber softener is 100 parts by mass or less based on 100 parts by mass of the rubber-like polymer, bleeding can be suppressed, and stickiness on the surface of the rubber composition can be suppressed.

Examples of the method for mixing the modified conjugated diene polymer mixture (C) with additives such as other rubbery polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, rubber softeners and the like include, but are not limited to, melt-kneading methods using a common mixer such as an open mill, a banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, a multi-screw extruder and the like; a method in which the respective components are dissolved and mixed, and then the solvent is removed by heating.

Among these methods, a melt kneading method using a roll, a banbury mixer, a kneader, or an extruder is preferable from the viewpoint of productivity and excellent kneading property. Further, any of a method of kneading the rubber-like polymer with other fillers, silane coupling agents and additives at once and a method of mixing the rubber-like polymer several times can be applied.

The rubber composition may be a vulcanized composition obtained by vulcanizing the rubber composition with a vulcanizing agent. Examples of the vulcanizing agent include, but are not limited to, radical initiators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur-containing compounds.

The sulfur-containing compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymer polysulfide compounds, and the like. The content of the vulcanizing agent is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, relative to 100 parts by mass of the rubber-like polymer. As the vulcanization method, conventionally known methods can be applied, and the vulcanization temperature is preferably 120 ℃ to 200 ℃ inclusive, more preferably 140 ℃ to 180 ℃ inclusive.

In the vulcanization, a vulcanization accelerator may be used as needed. As the vulcanization accelerator, conventionally known materials can be used, and examples thereof include, but are not limited to, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators. Examples of the vulcanization aid include, but are not limited to, zinc white and stearic acid. The content of the vulcanization accelerator is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 15 parts by mass, per 100 parts by mass of the rubber component.

In the rubber composition, various additives such as softening agents and fillers other than the above, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, lubricants and the like may be used within a range not to impair the object of the present embodiment. As the other softener, a known softener can be used. Examples of the other filler include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate. As the heat stabilizer, antistatic agent, weather stabilizer, aging inhibitor, colorant and lubricant, known materials can be used.

[ tires ]

The rubber composition is suitably used as a rubber composition for a tire.

The rubber composition can be applied to, but not limited to, various tire parts such as treads, tire carcasses, beads, and bead parts of various tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires. In particular, the rubber composition for a tire containing the modified conjugated diene polymer mixture (C) is excellent in the balance between low hysteresis loss properties and wet skid resistance and abrasion resistance after being vulcanized, and therefore is more suitable for use as a tread of a fuel-efficient tire or a high-performance tire.

Examples

The present embodiment will be described in more detail below by referring to specific examples and comparative examples, but the present embodiment is not limited to the following examples and comparative examples.

The materials used in examples and comparative examples and the evaluation methods of various characteristics are as follows.

[ purification of 1, 3-butadiene ]

1, 3-butadiene used in the polymerization of the modified conjugated diene polymer was purified by the following procedure.

(washing step)

In the circulating water amount of 1m³Hr, 0.1m of water for renewal (supplement)³Run at/hr.

The 1, 3-butadiene and the washing water were mixed using a static mixer (series of static mixers N60 manufactured by NORITAKE COMPANY LIMITED, Ltd.), and then transferred to a decanter, and separated into a1, 3-butadiene phase and an aqueous phase by the decanter.

The operation was carried out at a liquid temperature of 30 ℃ and a decanter pressure of 1.0 MPaG.

The residence time of the 1, 3-butadiene phase in the decanter was 30 minutes.

The aqueous phase separated by the decanter was introduced into a1, 3-butadiene removal tank, mixed with steam, heated at 89 ℃ and brought to a total pressure of 0.01MPaG to separate 1, 3-butadiene from the aqueous phase.

(oxygen removal step by deoxidant)

Next, a 10% aqueous solution of DICLEAN F-504 (manufactured by Tantaki Kasei Kogyo Co., Ltd.) was used as a deoxidizer, and a static mixer was used at 1m³The 1, 3-butadiene after the above (washing step) was mixed with the aqueous solution of the deoxidizer at a circulation flow rate of/hr, and liquid-liquid extraction was performed.

The resulting mixture was transferred to a decanter, and separated into a1, 3-butadiene phase and an aqueous phase by the decanter.

The residence time of the 1, 3-butadiene phase in the decanter was 30 minutes. The operation was carried out at a liquid temperature of 30 ℃ and a decanter pressure of 1.0 MPaG.

(polymerization inhibitor removing step)

Then, a 10% aqueous sodium hydroxide solution was further introduced into a packed column packed with a pall ring at a volume of 1m³Circulation flow rate/hr and the flow rate after the above-mentioned (oxygen removal step by deoxidizer)Mixing 1, 3-butadiene, extracting, transferring to other decanter, and separating into 1, 3-butadiene phase and water phase.

The residence time of the 1, 3-butadiene phase in the further decanter was 60 minutes. In the polymerization inhibitor removal step, the operation was carried out at a liquid temperature of 30 ℃ and a decanter pressure of 1.0 MPaG.

(dehydration step)

The 1, 3-butadiene phase separated by another decanter in the above-described (polymerization inhibitor removing step) was supplied with mixed hexane so that the 1, 3-butadiene concentration became 50 mass%, and then supplied to a dehydration column.

The azeotropic mixture of 1, 3-butadiene and water distilled from the top (overhead) of the dehydration column is cooled, condensed, transferred to a decanter, and separated into a1, 3-butadiene phase and an aqueous phase by the decanter.

The aqueous phase was removed, and the 1, 3-butadiene phase was returned to the inlet of the dehydration column, thereby continuously conducting the dehydration column step.

The mixture of dehydrated 1, 3-butadiene and hexane was taken out from the bottom (bottom) of the dehydration column.

(adsorption step)

The mixed solution of 1, 3-butadiene and hexane after the above-mentioned (dehydration step) was passed through a 500L adsorption dryer (vertical cylinder tank, manufactured by Hitachi, Ltd.) filled with activated alumina to remove a small amount of residual impurities in 1, 3-butadiene by adsorption, thereby obtaining purified 1, 3-butadiene.

[ purification of styrene ]

Styrene used for polymerization of the modified conjugated diene polymer was purified by the following procedure.

An aqueous solution of palladium chloride having a concentration of 0.6% was impregnated into gamma-alumina formed into a cylindrical shape of 3 mm. phi. times.3 mm, and dried at 100 ℃ for 1 day and night. Then, the dried product was subjected to reduction treatment at 400 ℃ for 16 hours under a hydrogen stream to obtain a composition of Pd (0.3%)/γ -Al₂O₃The hydrogenation catalyst of (1). 2000g of the obtained hydrogenation catalyst was packed in a tubular reactor, and the temperature of the catalyst was maintainedPurified styrene was obtained at 80 ℃ with 8 hours of circulation.

[ purification of n-hexane ]

N-hexane used for polymerization of the modified conjugated diene polymer was purified by the following procedure.

2000g of molecular sieve 13-X (UNION SHOWA) was charged into a tubular reactor and allowed to circulate at room temperature for 24 hours, whereby purified n-hexane was obtained.

[ analysis of purity of raw Material (calculation of Total impurities) ]

Quantitative analysis of allenes, acetylenes, and amines was performed as impurities in the raw materials.

Allenes and acetylenes were characterized/quantified by gas chromatography.

The column used was Rt-Alumina BOND/MAPD (Shimadzu corporation).

In addition, the amines were extracted with boric acid, and quantified by titration, and the total amount of impurities (ppm) was calculated.

[ (Property 1) amount of bonded styrene ]

The modified conjugated diene polymer was used as a sample, and 100mg of the sample was dissolved in chloroform to a volume of 100mL to prepare a measurement sample.

The amount (mass%) of bound styrene relative to 100 mass% of the modified conjugated diene polymer as a sample was measured from the amount of styrene absorbed by the phenyl group at an ultraviolet absorption wavelength (around 254 nm) (spectrophotometer "UV-2450" manufactured by Shimadzu corporation).

[ (physical Property 2) microstructure of butadiene moiety (1, 2-vinyl bond amount) ]

A sample of the modified conjugated diene polymer was dissolved in 10mL of carbon disulfide (50 mg) to prepare a measurement sample.

Using a solution vessel at 600-1000 cm^-1The infrared spectrum was measured, and the microstructure of the butadiene portion, that is, the 1, 2-vinyl bond content (mol%) was determined from the absorbance at a predetermined wave number according to the calculation formula of the Hampton method (the method described in R.R. Hampton, Analytical Chemistry 21,923(1949)) (manufactured by Nippon spectral Co., Ltd.) (the method is described inA Fourier transform infrared spectrophotometer "FT-IR 230").

[ (physical Property 3) molecular weight ]

The weight average molecular weight (Mw) was determined based on a calibration curve obtained using standard polystyrene by measuring a chromatogram using a GPC measurement apparatus (trade name "HLC-8320 GPC" manufactured by Tosoh corporation) to which 3 columns each containing a polystyrene gel as a filler were connected, and using an RI detector (trade name "HLC 8020" manufactured by Tosoh corporation) using a GPC measurement apparatus using a modified conjugated diene polymer as a sample₁) Number average molecular weight (Mn)₁) And molecular weight distribution (Mw)₁/Mn₁)。

THF (tetrahydrofuran) was used as eluent.

The column was used by connecting 3 units of the trade name "TSKgel Super Multipore HZ-H" manufactured by Tosoh corporation, and connecting the former to a trade name "TSK guard column Super MP (HZ) -H" manufactured by Tosoh corporation as a guard column.

10mg of a sample for measurement was dissolved in 20mL of THF to prepare a measurement solution, and 10. mu.L of the measurement solution was injected into a GPC measurement apparatus and measured at an oven temperature of 40 ℃ and a THF flow rate of 0.35 mL/min.

[ (Property 4) modification ratio based on the total amount of conjugated diene Polymer ]

The chromatogram measurement was performed by using the modified conjugated diene polymer as a measurement sample and by using the property that the modified basic polymer component is adsorbed on a GPC column using a silica gel as a filler.

The adsorption amount on the silica-based column was measured from the difference between the chromatogram measured with the polystyrene-based column and the chromatogram measured with the silica-based column in the measurement sample solution containing the measurement sample and low-molecular-weight internal standard polystyrene, and the modification ratio was determined.

Specifically, as described below.

Preparation of sample solution for measurement:

10mg of the above-mentioned sample for measurement and 5mg of standard polystyrene were dissolved in 20mL of THF (tetrahydrofuran) to prepare a sample solution for measurement.

GPC measurement conditions using polystyrene columns:

a10. mu.L sample solution for measurement was poured into the apparatus using "HLC-8320 GPC" product of Tosoh corporation and THF as an eluent, and a chromatogram was obtained using an RI detector under conditions of a column box temperature of 40 ℃ and a THF flow rate of 0.35 mL/min. The column was used by connecting 3 TSKgel Super Multi-HZ-H, a trade name of the protection column TSK guard column Super MP (HZ) -H, a trade name of the protection column manufactured by Tosoh.

GPC measurement conditions using a silica-based column:

a50. mu.L sample solution for measurement was poured into the apparatus using "HLC-8320 GPC" product of Tosoh corporation and THF as an eluent, and a chromatogram was obtained using an RI detector under conditions of a column box temperature of 40 ℃ and a THF flow rate of 0.5 mL/min. The column was used under the trade name "Zorbax PSM-1000S", "PSM-300S" or "PSM-60S", and the column was used under the trade name "DIOL 4.6X 12.5mm5 micron" as a guard column in the preceding stage.

The calculation method of the modification rate comprises the following steps:

the total peak area of the chromatogram obtained using the polystyrene column was set to 100, the peak area of the sample was set to P1, and the peak area of the standard polystyrene was set to P2; the modification ratio (%) was determined by the following formula, with the peak area of the chromatogram using the silica-based column taken as a whole as 100, the peak area of the sample as P3, and the peak area of the standard polystyrene as P4.

Modification rate (mass%) [1- (P2 × P3)/(P1 × P4) ] × 100

(in the above formula, P1+ P2 is P3+ P4 is 100.)

[ (Property 5) modification ratio of Low molecular weight component ]

According to the measurement (Property 3), a GPC measurement apparatus (trade name "HLC-8320 GPC" manufactured by Tosoh corporation) to which 3 columns each containing a polystyrene gel as a filler were connected was used, and a chromatogram was measured using an RI detector (trade name "HLC 8020" manufactured by Tosoh corporation), based on a chromatogram obtained using standard polystyreneThe weight average molecular weight (Mw) of the modified conjugated diene polymer was determined from the calibration curve₂) Number average molecular weight (Mn)₂) Molecular weight distribution (Mw)₂/Mn₂) And peak molecular weight (Mp) of the modified conjugated diene polymer₂)。

The peak molecular weight (Mp) is₂) The molecular weight of the peak top in the molecular weight curve or the peak top having the smallest molecular weight when a plurality of peak tops exist is defined as the peak molecular weight (Mp)₂) The spectrum height at the molecular weight of 1/2 was set to L1.

The peak molecular weight (Mp) was measured as a spectrum obtained by measurement using a silica column (physical property 3)₂) The height at molecular weight of 1/2 was set to L2.

The low molecular weight component was 1/2 having a molecular weight of the peak top.

The modification ratio of the low molecular weight component was calculated from 1-L1/L2.

[ degree of modification of Low molecular weight component ]

The degree of modification of the low-molecular-weight component is calculated by dividing the modification ratio (FL) of the low-molecular-weight component described above (property 5) by the modification ratio (FT) of the low-molecular-weight component described above (property 4) with respect to the total amount of the conjugated diene polymer.

Degree of modification of low molecular weight component (FL/FT). times.100

[ (Property 6) shrinkage factor (g') ]

The molecular weight was determined based on the solution viscosity and the light scattering method by measuring the chromatogram using a GPC-light scattering measuring apparatus with a viscosity detector in which 3 columns each containing a polystyrene gel as a filler were connected, using the modified conjugated diene polymer as a sample.

A mixed solution of tetrahydrofuran and triethylamine (THF in TEA: 5mL of triethylamine was mixed in 1L of tetrahydrofuran) was used as an eluent.

With respect to the pillars, the pillars will be protected: trade name "TSK guard column HHR-H" manufactured by Tosoh corporation and column: the products "TSKgel G6000 HHR", "TSKgel G5000 HHR" and "TSKgel G4000 HHR" manufactured by Tosoh corporation were used in combination.

A GPC-light scattering measuring apparatus (trade name "Viscotek TDAmax" manufactured by Malvern) equipped with a viscosity detector was used under conditions of an oven temperature of 40 ℃ and a THF flow rate of 1.0 mL/min.

10mg of the measurement sample was dissolved in 20mL of THF to prepare a measurement sample solution, and 200. mu.L of the measurement sample solution was injected into a GPC measurement apparatus and measured.

The intrinsic viscosity and the molecular weight of the obtained sample solution for measurement were expressed by a relational expression ([ eta ] molecular weight]＝KMα([η]: intrinsic viscosity, M: molecular weight) is logK-3.883 and α is 0.771, and a molecular weight M of 1000 to 20000000 is input to produce a standard intrinsic viscosity [. eta. ]]₀Relation to molecular weight M, for the standard intrinsic viscosity [. eta. ]]₀Relationship with molecular weight M, as intrinsic viscosity [. eta. ] at each molecular weight M]Relative to the standard intrinsic viscosity [. eta. ]]₀The intrinsic viscosity [ eta ] at each molecular weight M was calculated from the relationship of (A)]Relative to the standard intrinsic viscosity [. eta. ]]₀Eta of]/[η]₀The average value thereof was taken as the shrinkage factor (g').

In addition, g' is an average value of M in the range of 100 to 200 ten thousand.

[ production of modified conjugated diene Polymer ]

(modified conjugated diene Polymer A1)

A polymerization reactor was prepared by connecting 2 pressure vessels of a tank type having an internal volume of 10L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and a stirrer and a jacket for temperature control.

1, 3-butadiene from which moisture had been removed in advance was mixed under conditions of 22.2 g/min, 12.0 g/min for styrene, and 210 g/min for n-hexane. This mixture contained 9ppm of allenes, 15ppm of acetylenes and 2ppm of amines. The total of impurities was 26 ppm.

A static mixer was placed in the middle of the piping for supplying the mixed solution to the inlet of the 1 st reactor, and n-butyllithium for inerting the residual impurities was added to the static mixer at a rate of 0.0800 mmol/min, and after mixing, the mixed solution was continuously supplied to the bottom of the 1 st reactor.

Further, a mixed solution of piperidino lithium (abbreviated as "LA-1" in the table) and n-butyl lithium (prepared by mixing piperidino lithium and n-butyl lithium at a molar ratio of 0.75: 0.25, and 0.75: 1.00 piperidine: n-butyl lithium) which had been prepared in advance as a polymerization initiator at a rate of 0.0120 g/min was supplied to the bottom of the 1 st polymerization reactor vigorously mixed with a stirrer at a rate of 0.0800mmol (lithium molar ratio)/min to continuously carry out the polymerization reaction.

The temperature was controlled so that the temperature of the polymerization solution at the outlet of the top of the 1 st reactor was 65 ℃. The polymer solution was continuously supplied from the top of the 1 st reactor to the bottom of the 2 nd reactor by connecting the top of the 1 st reactor to the bottom of the 2 nd reactor. The temperature was controlled so that the temperature of the polymer at the outlet of the top of the 2 nd reactor was 70 ℃.

Subsequently, when the polymerization was sufficiently stabilized, 0.2g of an antioxidant (BHT) per 100g of the polymer was continuously added at 0.055 g/min (n-hexane solution) to the polymer solution discharged from the outlet of the 2 nd reactor, thereby terminating the polymerization reaction.

Extender oil (JOMO Process NC140, manufactured by JX Nikkiso Stone energy Co., Ltd.) was continuously added to 100g of the polymer together with the antioxidant, and the mixture was mixed by a static mixer.

The solvent was removed by steam stripping from the modified conjugated diene polymer solution containing the oil extender, to obtain a modified conjugated diene polymer a 1. Various measurements were made and the results are shown in Table 1.

The resulting polymer solution was further charged into a tank-type pressure vessel having an internal volume of 100L.

(modified conjugated diene Polymer A2)

Further, a mixed solution of piperidino lithium (abbreviated as "LA-1" in the table) and n-butyl lithium (prepared by mixing piperidino lithium and n-butyl lithium at a molar ratio of piperidine to n-butyl lithium of 0.75: 0.25, and 0.75: 1.00) which was prepared in advance as a polymerization initiator at a rate of 0.0157 g/min was supplied to the bottom of the 1 st polymerization reactor vigorously mixed with a stirrer at a rate of 0.144mmol (lithium molar ratio)/min to continue the polymerization reaction.

Subsequently, when the polymerization was sufficiently stabilized, bis (3-trimethoxysilylpropyl) methylamine (abbreviated as "A" in the table) as a modifier was continuously added at a rate of 0.0360 mmol/min to the polymer solution discharged from the outlet of the 2 nd reactor, and the polymer solution to which the modifier was added was mixed by a static mixer and modified.

An antioxidant (BHT) was continuously added to the modified polymer solution at 0.055 g/min (n-hexane solution) in an amount of 0.2g per 100g of the polymer, to terminate the modification reaction.

The solvent was removed by steam stripping from the modified conjugated diene polymer solution containing the oil extender, to obtain a modified conjugated diene polymer a 2. Various measurements were made and the results are shown in Table 1.

The obtained modified conjugated diene polymer solution was further charged into a tank-type pressure vessel having an internal volume of 100L.

(modified conjugated diene Polymer A3, modified conjugated diene Polymer B1-B3)

The modified conjugated diene polymer A3 and the modified conjugated diene polymers B1 to B3 were obtained in the same manner as the modified conjugated diene polymer a2 by adjusting the amount of the polymerization initiator added, the amount of the polar substance added, the type of the modifier, and the amount of the modifier added, as shown in tables 1 to 2 below.

In tables 1 and 2, modifier "B" is N, N, N '-tris (3-trimethoxysilylpropyl) -N' - [3- (2, 2-dimethoxy-1-aza-2-silacyclopentane) propyl ] -1, 3-propanediamine.

(modified conjugated diene Polymer A4)

1, 3-butadiene from which moisture had been removed in advance was mixed under conditions of 18.0 g/min, 9.7 g/min for styrene and 145 g/min for n-hexane. This mixture contained 9ppm of allenes, 15ppm of acetylenes and 2ppm of amines. The total of impurities was 26 ppm.

A static mixer was provided in the middle of the piping for supplying the mixed solution to the inlet of the reactor, and n-butyllithium for inerting the residual impurities was added to the static mixer at 0.0648 mmol/min, and was continuously supplied to the bottom of the reactor after mixing.

Further, 2-bis (2-tetrahydrofuryl) propane as a polar substance was fed at a rate of 0.0216 g/min to the bottom of the polymerization reactor vigorously mixed with a stirrer, and n-butyllithium (abbreviated as "NBL" in the table) as a polymerization initiator was fed at a rate of 0.0864 mmol/min to continue the polymerization reaction continuously. The temperature was controlled so that the temperature of the polymer solution at the outlet of the top of the reactor was 75 ℃.

When the polymerization was sufficiently stabilized, 3- (4-methyl-1-piperazinyl) propyltriethoxysilane (abbreviated as "C" in the table) as a modifier was continuously added to the polymer solution discharged from the outlet of the reactor at a rate of 0.0432 mmol/min, and the polymer solution to which the modifier was added was mixed by a static mixer to carry out a modification reaction.

The antioxidant (BHT) was continuously added to the polymer solution subjected to the modification reaction at 0.055 g/min (n-hexane solution) to 0.2g per 100g of the polymer, to terminate the coupling reaction. Oil (JOMO Process NC140, manufactured by JX Nikkiso Risk Ltd.) was continuously added to 100g of the polymer together with the antioxidant in an amount of 37.5g, and the mixture was mixed by a static mixer.

The solvent was removed by steam stripping from the modified conjugated diene polymer solution containing the oil extender, to obtain a modified conjugated diene polymer a 4. Various measurements were carried out, and the results are shown in table 1.

(modified conjugated diene polymers A5 to A11 and modified conjugated diene polymers B4 to B10)

Modified conjugated diene polymers a5 to a11 and modified conjugated diene polymers B4 to B10 were obtained in the same manner as the modified conjugated diene polymer a4 by adjusting the amount of addition of the polymerization initiator, the amount of addition of the polar substance, the type of the modifier, and the amount of addition of the modifier as shown in tables 1 and 2 below.

The results of various measurements are shown in tables 1 and 2.

The obtained modified conjugated diene polymer solutions were each charged into a tank-type pressure vessel having an internal volume of 100L.

In tables 1 and 2, modifier "D" was tetraglycidyl-1, 3-bisaminomethylcyclohexane.

Modifier "E" is tris (3-trimethoxysilylpropyl) amine.

In the table, when 2 numerical values are described in the polymerization temperature, the former indicates the polymerization temperature of the 1 st stage, and the latter indicates the polymerization temperature of the 2 nd stage.

The modifiers are 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-piperazinyl) 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 polymer a6 and the polymer solution of the modified conjugated diene polymer B1 produced by the above method and fed into a tank-type pressure vessel were mixed in such a manner that the mass ratio of the modified conjugated diene polymer a6 to the modified conjugated diene polymer B1 was (a 6): (B1) 70: 30, and joining them together in a pipe. After the confluence, the mixture was stirred and mixed by a rotary stirrer.

Subsequently, the solvent was removed by steam stripping, whereby a modified conjugated diene polymer mixture C1 was obtained.

The results of various measurements are shown in Table 3.

Examples 2 to 21 modified conjugated diene Polymer mixtures C2 to C21

The combination of the modified conjugated diene polymer a and the modified conjugated diene polymer B used was changed, and the content of the modified conjugated diene polymer a in the modified conjugated diene polymer mixture C was changed as shown in tables 3 and 4, and the modified conjugated diene polymer mixtures C2 to C21 were obtained in the same manner as the modified conjugated diene polymer mixture C1.

The results of various measurements are shown in tables 3 and 4.

Examples 22 to 42 and comparative examples 1 to 21

Modified conjugated diene polymer compositions containing the respective raw material rubbers were obtained in the following compounding ratios using the samples (modified conjugated diene polymer mixtures C1 to C21, modified conjugated diene polymers a1 to a11, and modified conjugated diene polymers B1 to B10) shown in tables 1 to 4 as the raw material rubbers.

Sample: 100 parts by mass

Silica (trade name "Ultrasil 7000 GR" manufactured by Evonik Degussa, nitrogen adsorption specific surface area: 175m²(iv)/g): 75 parts by mass

A silane coupling agent (manufactured by Evonik Degussa, trade name "Si 75" (tetraethoxysilylpropyl disulfide)): 6 parts by mass

Process oil (manufactured by JX ri shi energy source company, trade name "NC 140"): 42 parts by mass

Carbon black (trade name "SEAST KH (N339)" manufactured by Toshiba carbon Co., Ltd.), iodine adsorption amount of 90g/kg, and CTAB specific surface area of 95m²(iv)/g): 5 parts by mass

Zinc white (manufactured by mitsui metal mining corporation, trade name "zinc white No. 1"): 2.5 parts by mass

Stearic acid: 1.0 part by mass

Wax (product name "Sunnoc" manufactured by Dainiji chemical industries, Ltd., yellowish white granular color, solidification point of 65 ℃ or higher, relative density of 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-benzothiazylsulfenamide): 1.7 parts by mass

Vulcanization accelerator (diphenylguanidine): 2.0 parts by mass

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

As the first kneading step, a kneader (internal volume: 0.5L) equipped with a temperature control device was used to knead the modified conjugated diene polymer (modified SBR1), silica inorganic filler (silica), silane coupling agent and process oil for 4 minutes at a filling rate of 65% and a rotor speed of 50 rpm. In this case, the temperature of the kneader is controlled so that the modified conjugated diene polymer composition is obtained at a discharge temperature (compounding product) of 155 to 160 ℃.

Next, as a second kneading step, the compound obtained above was cooled to room temperature, and then carbon black, zinc white, stearic acid, wax and an antioxidant were added and kneaded for 3 minutes by the kneader. In this case, the discharge temperature (mixture) was also adjusted to 155 to 160 ℃ by controlling the temperature of the mixer. After that, the above compound was discharged from the kneader, and immediately after passing the compound 6 times through a 10-inch Φ mill, a sheet-like unvulcanized rubber composition was produced, cooled, and then the processability was evaluated.

Further, the unvulcanized composition was heated at 70 ℃ for 30 minutes in an oven, and then, as a third kneading stage, sulfur and a vulcanization accelerator were added to a 10-inch Φ roll mill set at 70 ℃ to knead the mixture, thereby obtaining a composition. Thereafter, the residue of the composition was subjected to vulcanization molding at 160 ℃ for 20 minutes by a press vulcanizer to obtain a sulfide. The physical properties of the rubber composition were measured after vulcanization. The results of the physical property measurements are shown in tables 5 to 10 below.

[ methods of measuring physical Properties ]

(Mooney viscosity of Compound)

After the second-stage kneading, the rubber composition was used as a sample, and the Mooney viscosity was measured using an L-shaped rotor in accordance with JIS K6300 using a Mooney viscometer (trade name "VR 1132" manufactured by Shanghai Co., Ltd.).

The measurement temperature was set at 100 ℃.

The sample was first preheated at the test temperature for 1 minute, then the rotor was rotated at 2rpm, and the torque after 4 minutes was measured as the Mooney viscosity (ML)₍₁₊₄₎)。

The result of comparative example 6 was indexed with 100 as an index of workability. The larger the index, the better the processability.

(viscoelasticity parameter)

For the rubber composition after vulcanization, the viscoelasticity parameter was measured in a torsional mode using a viscoelasticity tester "ARES" manufactured by Rheometric Scientific. The results for the rubber composition of comparative example 6 were set to 100, and the respective measured values were indexed.

The tan δ measured at 0 ℃ under the conditions of frequency 10Hz and strain 1% was used as an index of wet grip performance. The larger the value, the better the wet grip. Further, the reciprocal of tan δ measured at 50 ℃ under conditions of a frequency of 10Hz and a strain of 3% was used as an index of fuel economy. The larger the value, the better the fuel economy.

(tensile breaking Strength)

The rubber composition after vulcanization was subjected to an exponential reaction with the result of comparative example 6 being 100, by measuring the tensile breaking strength according to the tensile test method of JIS K6251.

(abrasion resistance)

The rubber composition after vulcanization was indexed with the result of comparative example 6 being 100 by measuring the abrasion loss at a load of 44.4N and 1000 revolutions in accordance with JIS K6264-2 using an AKRON abrasion tester (manufactured by Anda Seiko Seisaku-Sho Ltd.). The larger the index is, the better the abrasion resistance is.

The predicted values 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 were calculated from the evaluation results of the compositions of comparative examples 1 to 21 using only a single substance of each of the modified conjugated diene polymers a1 to a11 and the modified conjugated diene polymers B1 to B10, taking into account the mass fractions of the modified conjugated diene polymer a and the modified conjugated diene polymer B.

For example, in the case of the modified conjugated diene polymer mixture C1, since the mass ratio of the modified conjugated diene polymer a to the modified conjugated diene polymer B is 70: thus, the value (predicted value of the evaluation result of the modified conjugated diene polymer C1) × (70/100) + (evaluation result of the modified conjugated diene polymer B) × (30/100) was calculated.

The actual results are likewise compared with the respectively calculated predicted values.

The predicted values and the measurement results are shown in tables 5 to 8 below.

In tables 5 to 8, the left-hand numerical values in the columns of the respective examples are actual measured values, and the right-hand numerical values are predicted values calculated from mass fractions.

[ Table 5]

Left: actually measuring, and rightwards: value predicted from weight fraction

[ Table 6]

[ Table 7]

[ Table 8]

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 21 were inferior in abrasion resistance to the compositions using the modified conjugated diene polymers A1 to A11 alone, but were excellent in processability.

Further, it is found that the composition is more excellent in the actual measurement results and has a good balance between low hysteresis loss properties, wet skid resistance, abrasion resistance and processability, as compared with the estimated value of the composition of the modified conjugated diene polymer mixture C in which the mass fractions of the modified conjugated diene polymer a and the modified conjugated diene polymer B are taken into consideration. Similarly, the modified conjugated diene polymers were superior in processability to compositions using a single modified conjugated diene polymer B1 to B10, respectively, but excellent in abrasion resistance.

It is also found that the actual measurement results are more excellent than the estimated values of evaluation of the composition using the modified conjugated diene polymer mixture C in consideration of the mass fractions of the modified conjugated diene polymer a and the modified conjugated diene polymer B, and the balance between the hysteresis loss resistance, the wet skid resistance, the abrasion resistance, and the processability is good. In addition, it was confirmed that the tensile strength was practically sufficient.

In order to obtain the modified conjugated diene polymer mixture C, the modified conjugated diene polymer a in a state where the solvent was removed after the polymerization and the modified conjugated diene polymer B were not mixed, but the modified conjugated diene polymer a in a state of a solution before the solvent was removed after the polymerization and the modified conjugated diene polymer B were mixed and finished. Thus, the step of finishing was originally required 2 times, but the efficiency of the production step can be improved by obtaining the modified conjugated diene polymer C in 1 finishing step.

Industrial applicability

The method for producing a modified conjugated diene polymer mixture of the present invention has industrial applicability in the fields of tire treads, interior/exterior parts of automobiles, vibration-proof rubbers, belts, footwear, foams, various industrial product applications, and the like.

Claims

1. A process for producing a modified conjugated diene polymer mixture, which comprises,

continuously polymerizing a modified conjugated diene polymer A having a weight average molecular weight Mw of 70X 10 as measured by GPC (gel permeation chromatography)⁴300X 10 above⁴The modified conjugated diene polymer B has an Mw of 10X 10 as measured by GPC⁴Above and less than 70 × 10⁴，

Solution-mixing a polymer solution containing the modified conjugated diene polymer A and a polymer solution containing the modified conjugated diene polymer B,

wherein the modified conjugated diene polymer mixture (C) has a molecular weight distribution Mw/Mn of 1.8 to 4.5,

the difference Δ Mw between the weight average molecular weights of the modified conjugated diene polymer A and the modified conjugated diene polymer B is 50X 10⁴In the above-mentioned manner,

the modification ratio of the modified conjugated diene polymer mixture (C) to the total amount of conjugated diene polymers is adjusted to 50% by mass or more,

the mixing mass ratio A/B of the modified conjugated diene polymer A and the modified conjugated diene polymer B in the modified conjugated diene polymer mixture (C) is adjusted to 90/10-40/60.

2. The method for producing the modified conjugated diene polymer mixture according to claim 1, wherein the modified conjugated diene polymer A has an Mw of 100X 10⁴300X 10 above⁴The following.

3. The method for producing the modified conjugated diene polymer mixture according to claim 1 or 2, wherein the shrinkage factor g' of the modified conjugated diene polymer A and/or the modified conjugated diene polymer B measured by 3D-GPC is 0.70 or more and 1.0 or less.

4. The method for producing the modified conjugated diene polymer mixture according to claim 1 or 2, wherein the shrinkage factor g' of the modified conjugated diene polymer A and/or the modified conjugated diene polymer B measured by 3D-GPC is 0.30 or more and less than 0.70.

5. The method for producing a modified conjugated diene polymer mixture according to claim 1 or 2, wherein,

the modified conjugated diene polymer A and/or the modified conjugated diene polymer B has a functional group represented by the following general formula (1) at the polymerization initiation end,

[ solution 1]

In the general formula (1), R¹And R²Is selected from the group consisting of C1-12 alkyl, C3-14 cycloalkyl and C6-20Any one of the group consisting of aryl, R¹And R²May be the same or different; here, R¹And R²May be bonded to form a cyclic structure together with the adjacent nitrogen atom, R in this case¹And R²Is a hydrocarbon group having 4 to 12 carbon atoms in total; r¹And R²May have an unsaturated bond or a branched structure.

6. The method for producing the modified conjugated diene polymer mixture according to claim 5, wherein the modified conjugated diene polymer A and/or the modified conjugated diene polymer B has a functional group represented by the general formula (1) at a polymerization initiation end, and has a functional group containing an alkoxysilyl group and an amine at a different end from the polymerization initiation end having the functional group represented by the general formula (1).

7. The method for producing a modified conjugated diene polymer mixture according to claim 1 or 2, wherein, with respect to the modified conjugated diene polymer B,

a modification ratio of 50% by mass or more relative to the total amount of the conjugated diene polymer;

1/2, which is equal to or more than 1/2, the modification ratio of the modified conjugated diene polymer with respect to the total amount, and the molecular weight of the component is equal to or greater than the molecular weight of the peak top in the molecular weight curve or the molecular weight of the peak top having the smallest molecular weight when a plurality of the peak tops are present;

the modified conjugated diene polymer B has a nitrogen content of 3 to 70 mass ppm.