Conjugated diene polymer, conjugated diene polymer composition, rubber crosslinked product, and tire

Abstract

The present invention provides a conjugated diene polymer which at least contains conjugated diene monomer units, the shrinkage factor of the high molecular weight fraction is 0.4 to 0.8, the adsorption rate of the high molecular weight fraction to silica is 75% or less, and the adsorption rate of the medium molecular weight fraction to silica is 40 to 100%.

Description

Technical Field

[0001] The present invention relates to a conjugated diene polymer, a conjugated diene polymer composition, a rubber crosslinked product, and a tire. More specifically, the present invention relates to a conjugated diene polymer having excellent processability and capable of forming a rubber crosslinked product having excellent fuel economy, and a conjugated diene polymer composition, a rubber crosslinked product, and a tire obtained by using such a conjugated diene polymer. Background Art

[0002] In recent years, due to the increasing concern about environmental problems, a polymer composition for automotive tires is also required to have excellent fuel economy. As a polymer composition for automotive tires, for example, a polymer composition containing a conjugated diene polymer such as polybutadiene and a butadiene-styrene copolymer, and a filler such as carbon black and silica can be used.

[0003] For example, Patent Document 1 discloses the following method: when a polymerization initiator is added to a monomer containing a conjugated diene compound in a hydrocarbon solvent to obtain a polymerization solution containing a conjugated diene polymer, the polymerization initiator is further added once or divided into two or more times during the polymerization reaction.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-172548. Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] According to the conjugated diene polymer obtained by the technique of Patent Document 1 above, by compounding a filler such as silica, the fuel economy can be improved, but the processability is insufficient. Therefore, improvement of the processability is desired.

[0009] The present invention has been made in view of the above problems, and an object of the present invention is to provide a conjugated diene polymer having excellent processability and capable of forming a rubber crosslinked product having excellent fuel economy. In addition, an object of the present invention is to provide a conjugated diene polymer composition, a rubber crosslinked product, and a tire obtained by using such a conjugated diene polymer, and a method for producing such a conjugated diene polymer.

[0010] Means for Solving the Problems

[0011] The inventors of the present invention conducted in-depth research to achieve the above object, and as a result, found that the above object can be achieved by making the shrinkage factor and the adsorption rate to silica of the high molecular weight component constituting the conjugated diene polymer, and the adsorption rate of the medium molecular weight component to silica within a specific range, thereby completing the present invention.

[0012] That is, according to the present invention, there is provided a conjugated diene polymer containing at least conjugated diene monomer units, wherein the shrinkage factor of the high molecular weight component is 0.4 to 0.8, the adsorption rate of the high molecular weight component to silica is 75% or less, and the adsorption rate of the medium molecular weight component to silica is 40 to 100%.

[0013] In the conjugated diene polymer of the present invention, it is preferable that the shrinkage factor of the medium molecular weight component is 0.8 to 1.2.

[0014] In the conjugated diene polymer of the present invention, it is preferable that the adsorption rate of the high molecular weight component to silica is 10 to 70%.

[0015] The conjugated diene polymer of the present invention preferably has two or more molecular weight peaks.

[0016] The conjugated diene polymer of the present invention is preferably a copolymer having the above conjugated diene monomer units and aromatic vinyl monomer units.

[0017] In the conjugated diene polymer of the present invention, it is preferable that the molecular weight Mp_ LOW of the low molecular weight component is in the range of 100,000 to 190,000.

[0018] According to the present invention, there is provided a conjugated diene polymer composition containing the above conjugated diene polymer and a filler.

[0019] Furthermore, according to the present invention, there are provided a rubber crosslinked product obtained by crosslinking the above conjugated diene polymer composition and a tire including such a rubber crosslinked product.

[0020] Furthermore, according to the present invention, there can be provided a method for producing a conjugated diene-based polymer, comprising: a first step of polymerizing a monomer containing a conjugated diene compound in an inert solvent in the presence of a polymerization initiator to obtain a solution containing a polymer chain having a living end; a second step of subjecting a part of the polymer chain having a living end obtained in the first step to a coupling reaction to thereby form a coupled polymer chain and obtain a solution containing the coupled polymer chain and the polymer chain having a living end; and a third step of further polymerizing a monomer containing a conjugated diene compound with the polymer chain having a living end after the coupling reaction is carried out in the second step, wherein in at least one of the first step and the third step, as the monomer for polymerization, a monomer containing a vinyl compound in addition to the conjugated diene compound is used, and the vinyl compound is a vinyl compound containing a functional group capable of interacting with silica.

[0021] In the method for producing a conjugated diene-based polymer of the present invention, it is preferable to additionally add a polymerization initiator at any timing during the polymerization in the first step, at the initiation of the polymerization in the third step, and during the polymerization in the third step.

[0022] Advantages of the Invention

[0023] According to the present invention, it is possible to provide a conjugated diene-based polymer having excellent processability and capable of forming a rubber crosslink having excellent fuel economy. In addition, according to the present invention, it is also possible to provide a conjugated diene-based polymer composition, a rubber crosslink, and a tire obtained by using such a conjugated diene-based polymer, and to provide a method for producing such a conjugated diene-based polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 (A), Figure 1 (B) is a graph showing an example of a GPC chart in the case where the conjugated diene-based polymer of the present invention exhibits a unimodal distribution.

[0025] Figure 2 (A), Figure 2 (B) is a graph showing an example of a GPC chart in the case where the conjugated diene-based polymer of the present invention exhibits a bimodal distribution.

[0026] Figure 3 (A), Figure 3 (B) is a graph showing an example of a GPC chart in the case where the conjugated diene-based polymer of the present invention exhibits a bimodal distribution.

[0027] Figure 4 (A), Figure 4(B) is a graph showing an example of a GPC chart in the case where the conjugated diene polymer of the present invention exhibits a trimodal distribution.

[0028] Figure 5 (A), Figure 5 (B) is a graph showing an example of a GPC chart in the case where the conjugated diene polymer of the present invention exhibits a tetramodal distribution.

[0029] Figure 6 It is an example of a graph showing the relationship between molecular weight and the intrinsic viscosity [η] measured by 3D-GPC, the intrinsic viscosity [η]0 of a linear polymer, and the shrinkage factor g'.

[0030] Figure 7 It is a graph schematically showing the GPC measurement results obtained using a styrene-based column and a silica-based column. Detailed Description

[0031] <Conjugated Diene Polymer>

[0032] The conjugated diene polymer of the present invention contains at least conjugated diene monomer units. The shrinkage factor of the high molecular weight fraction in the conjugated diene polymer is 0.4 to 0.8. The adsorption rate of the high molecular weight fraction in the conjugated diene polymer to silica is 75% or less. The adsorption rate of the medium molecular weight fraction in the conjugated diene polymer to silica is 40 to 100%.

[0033] The conjugated diene polymer of the present invention contains conjugated diene monomer units. Examples of the conjugated diene compound used to form the conjugated diene monomer units include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene. Among these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is more preferred.

[0034] In addition, the conjugated diene polymer of the present invention is preferably a copolymer having conjugated diene monomer units and aromatic vinyl monomer units. Examples of the aromatic vinyl compound used to form the aromatic vinyl monomer units include styrene, methylstyrene, ethylstyrene, tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, vinylnaphthalene, etc. Among these, styrene is preferred. Based on the total amount of all monomers in the conjugated diene polymer of the present invention being 100% by weight, the content ratio of the aromatic vinyl monomer units in the conjugated diene polymer of the present invention is preferably 3 to 50% by weight, more preferably 4 to 50% by weight. By making the content ratio of the aromatic vinyl monomer units within the above range, the fuel economy of the resulting rubber crosslinked product can be further improved.

[0035] In addition, the conjugated diene polymer of the present invention preferably contains, in addition to conjugated diene monomer units and aromatic vinyl monomer units, units of a vinyl compound, where the vinyl compound is a vinyl compound containing a functional group capable of interacting with silica.

[0036] As the vinyl compound containing a functional group capable of interacting with silica for forming the units of the vinyl compound containing a functional group capable of interacting with silica, any compound containing a functional group capable of interacting with silica and a vinyl group may be used, and there is no particular limitation. Here, the functional group capable of interacting with silica refers to a functional group capable of forming a covalent bond between the functional group and the silica surface, or a functional group capable of forming an intermolecular force weaker than a covalent bond (for example, ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.). There is no particular limitation on such a functional group capable of interacting with silica, and examples include nitrogen atom-containing functional groups, silicon atom-containing functional groups, oxygen atom-containing functional groups, etc. Among these, from the viewpoint of strong interaction with silica, silicon atom-containing functional groups are preferred.

[0037] As a preferred form of the vinyl compound containing a functional group capable of interacting with silica, a vinyl compound containing a silicon atom-containing functional group, a compound represented by the following general formula (1) can be preferably used.

[0038] [Chemical formula 1]

[0039]

[0040] In the above general formula (1), X 1 represents a chemical single bond or a lower alkylene group, X2 , X 3 and X 4 each independently represents a substituted amino group, a hydrocarbyloxy group, or a hydrocarbyl group which may have substituents.

[0041] In the above general formula (1), X 1 is a chemical single bond or a divalent hydrocarbyl group, preferably a chemical single bond. Examples of the divalent hydrocarbyl group include an alkylene group, an alkenylene group, an arylene group, or a group in which an arylene group is bonded to an alkylene group.

[0042] Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, etc. Examples of the alkenylene group include a vinylidene group, an ethane-1,1-diyl group, etc. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, etc. Examples of the group in which an arylene group is bonded to an alkylene group include a group in which a phenylene group is bonded to a methylene group, a group in which a phenylene group is bonded to an ethylene group, etc. When X 1 is a divalent hydrocarbyl group, X 1 is preferably an arylene group, more preferably a phenylene group.

[0043] In the above general formula (1), X 2 , X 3 and X 4 each independently represents a substituted amino group, a hydrocarbyloxy group, or a hydrocarbyl group which may have substituents. Preferably, at least one of X 2 , X 3 and X 4 is a substituted amino group, and more preferably two of X 2 , X 3 and X 4 are substituted amino groups.

[0044] As the substituted amino group which can form X 2 , X 3 and X 4 , a group represented by the following general formula (2) is preferred.

[0045] [Chemical formula 2]

[0046]

[0047] In the above general formula (2), R 1 and R 2 may be bonded to each other or may not be bonded to each other. When R 1 and R 2 are not bonded to each other, R 1 and R 2 each independently represents a hydrocarbyl group which may have substituents or a trihydrocarbylsilyl group. When R 1 and R 2 are bonded to each other, R 1 and R2 represents a lower alkylene group which may contain at least one selected from a nitrogen atom, an oxygen atom, a sulfur atom and a silicon atom.

[0048] As the hydrocarbon group capable of forming R 1 and R 2 there may be mentioned: chain-like alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl; cyclic alkyl groups such as cyclopentyl, cyclohexyl; aryl groups such as phenyl, benzyl, naphthyl. Among these, chain-like alkyl groups are preferred, and methyl or ethyl is more preferred.

[0049] When the hydrocarbon group capable of forming R 1 and R 2 has a substituent, there may be mentioned a hydrocarbon group having a hydrocarbyloxy group as a substituent, etc. As the hydrocarbon group having a hydrocarbyloxy group as a substituent, there may be mentioned: alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, methoxyethyl; aryloxyalkyl groups such as phenoxymethyl.

[0050] As specific examples of the trihydrocarbylsilyl group capable of forming R 1 and R 2 there may be mentioned trialkylsilyl groups such as trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl.

[0051] When R 1 and R 2 are bonded to each other, as the lower alkylene group capable of forming R 1 and R 2 there may be mentioned: alkylene groups such as trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, dodecamethylene, 2,2,4-trimethylhexane-1,6-diyl; enediyl groups such as pent-2-ene-1,5-diyl. Further, when the lower alkylene group capable of forming R 1 and R 2 contains at least one selected from a nitrogen atom, an oxygen atom, a sulfur atom and a silicon atom, as the lower alkylene group containing at least one selected from a nitrogen atom, an oxygen atom, a sulfur atom and a silicon atom, there may be mentioned a group represented by -CH=N-CH=CH-, a group represented by -CH=N-CH2-CH2-, a group represented by -CH2-CH2-O-CH2-CH2-, a group represented by -CH2-CH2-S-CH2-CH2-, a group represented by -CH2-CH2-SiH2-CH2-CH2-, a group represented by -CH2-CH2-SiMe2-CH2-CH2-, a group represented by -CH2-CH2-SiEt2-CH2-CH2-.

[0052] Preferably, R 1 and R2 is an alkyl group, or R 1 and R 2 bond to each other to form an alkylene group, more preferably R 1 and R 2 are alkyl groups, and further preferably R 1 and R 2 are methyl or ethyl.

[0053] As specific examples of the group represented by the above general formula (2) when R 1 and R 2 in the general formula (2) are hydrocarbon groups, there may be mentioned: dialkylamino groups such as dimethylamino, diethylamino, ethylmethylamino, di-n-propylamino, diisopropylamino, di-n-butylamino, diisobutylamino, di-sec-butylamino, di-tert-butylamino; diarylamino groups such as diphenylamino, etc. Among these, dialkylamino groups are preferred, and dimethylamino, diethylamino, and di-n-butylamino are more preferred.

[0054] As specific examples of the group represented by the above general formula (2) when R 1 and R 2 in the general formula (2) are hydrocarbon groups having a hydrocarbyloxy group as a substituent, there may be mentioned bis(alkoxymethyl)amino groups such as bis(methoxymethyl)amino, bis(ethoxymethyl)amino, etc.

[0055] As specific examples of the group represented by the above general formula (2) when R 1 and R 2 in the general formula (2) are trihydrocarbylsilyl groups, there may be mentioned trialkylsilylamino groups containing bis(trimethylsilyl)amino, bis(tert-butyldimethylsilyl)amino, N-trimethylsilyl-N-methylamino, etc.

[0056] As specific examples of the group represented by the above general formula (2) when R 1 and R 2 bond to each other to form a hydrocarbylene group, there may be mentioned 1-aziridinyl, 1-pyrrolidinyl, 1-piperidinyl, 1-hexamethyleneimino, 1-heptamethyleneimino, 1-octamethyleneimino, 1-decamethyleneimino, 1-dodecamethyleneimino, etc., 1-alkyleneimino groups.

[0057] As specific examples of the group represented by the above general formula (2) when R 1 and R 2 bond to each other to form a hydrocarbylene group containing a nitrogen atom and / or an oxygen atom, there may be mentioned 1-imidazolyl, 4,5-dihydro-1-imidazolyl, morpholinyl, etc.

[0058] As the group represented by the above general formula (2), dialkylamino and 1-alkylideneamino are preferred, dialkylamino is more preferred, and dimethylamino, diethylamino, and di-n-butylamino are further preferred.

[0059] In the above general formula (1), as the group capable of forming X 2 、X 3 and X 4 Examples of the alkoxy group include alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, and tert-butoxy; aryloxy groups such as phenoxy and benzyloxy.

[0060] In the above general formula (1), as the group capable of forming X 2 、X 3 and X 4 Examples of the hydrocarbon group include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl; aryl groups such as phenyl, 4-methyl-1-phenyl, and benzyl.

[0061] When the hydrocarbon group capable of forming X 2 、X 3 and X 4 has a substituent, examples include a hydrocarbon group having an alkoxy group as a substituent, such as alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, and ethoxyethyl.

[0062] As X 1 is a chemical single bond, X 2 、X 3 and X 4Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) when one of them is a substituted amino group include: (dimethylamino)dimethylvinylsilane, (ethylmethylamino)dimethylvinylsilane, (dipropylamino)dimethylvinylsilane, (diisopropylamino)dimethylvinylsilane, (dimethylamino)diethylvinylsilane, (ethylmethylamino)diethylvinylsilane, (dipropylamino)diethylvinylsilane, (diisopropylamino)diethylvinylsilane and other (dialkylamino)dialkylvinylsilanes; [bis(trimethylsilyl)amino]dimethylvinylsilane, [bis(tert-butyldimethylsilyl)amino]dimethylvinylsilane, [bis(trimethylsilyl)amino]diethylvinylsilane, [bis(tert-butyldimethylsilyl)amino]diethylvinylsilane and other [bis(trialkylsilyl)amino]dialkylvinylsilanes; (dimethylamino)bis(methoxymethyl)vinylsilane, (dimethylamino)bis(methoxyethyl)vinylsilane, (dimethylamino)bis(ethoxymethyl)vinylsilane, (dimethylamino)bis(ethoxyethyl)vinylsilane, (diethylamino)bis(methoxymethyl)vinylsilane, (diethylamino)bis(methoxyethyl)vinylsilane, (diethylamino)bis(ethoxymethyl)vinylsilane, (diethylamino)bis(ethoxyethyl)vinylsilane and other (dialkylamino)bis(alkoxyalkyl)vinylsilanes; pyrrolidinyldimethylvinylsilane, piperidinyldimethylvinylsilane, hexamethyleneiminodimethylvinylsilane, 4,5-dihydroimidazolydimethylvinylsilane, morpholinodimethylvinylsilane and other cyclic amino dialkylvinylsilane compounds, etc.

[0063] As X in the above general formula (1) 1 is a divalent hydrocarbon group, X 2 , X 3 and X 4Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) when one of them is a substituted amino group include: (dimethylamino)dimethyl-4-vinylphenylsilane, (dimethylamino)dimethyl-3-vinylphenylsilane, (diethylamino)dimethyl-4-vinylphenylsilane, (diethylamino)dimethyl-3-vinylphenylsilane, (dipropylamino)dimethyl-4-vinylphenylsilane, (dipropylamino)dimethyl-3-vinylphenylsilane, (dibutylamino)dimethyl-4-vinylphenylsilane, (dibutylamino)dimethyl-3-vinylphenylsilane, (dimethylamino)diethyl-4-vinylphenylsilane, (dimethylamino)diethyl-3-vinylphenylsilane, (diethylamino)diethyl-4-vinylphenylsilane, (diethylamino)diethyl-3-vinylphenylsilane, (dipropylamino)diethyl-4-vinylphenylsilane, (dipropylamino)diethyl-3-vinylphenylsilane, (dibutylamino)diethyl-4-vinylphenylsilane, (dibutylamino)diethyl-3-vinylphenylsilane, etc., (dialkylamino)dialkylvinylphenylsilane, etc.

[0064] As X in the above general formula (1) 1 is a chemical single bond, X 2 , X 3 and X 4Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) when two of them are substituted amino groups include: bis(dimethylamino)methylvinylsilane, bis(diethylamino)methylvinylsilane, bis(di-n-propylamino)methylvinylsilane, bis(di-n-butylamino)methylvinylsilane, bis(dimethylamino)ethylvinylsilane, bis(diethylamino)ethylvinylsilane, bis(di-n-propylamino)ethylvinylsilane, bis(di-n-butylamino)ethylvinylsilane and other bis(dialkylamino)alkylvinylsilanes; bis[bis(trimethylsilyl)amino]methylvinylsilane, bis[bis(tert-butyldimethylsilyl)amino]methylvinylsilane, bis[bis(trimethylsilyl)amino]ethylvinylsilane, bis[bis(tert-butyldimethylsilyl)amino]ethylvinylsilane and other bis[bis(trialkylsilyl)amino]alkylvinylsilanes; bis(dimethylamino)methoxymethylvinylsilane, bis(dimethylamino)methoxyethylvinylsilane, bis(dimethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane, bis(diethylamino)methoxymethylvinylsilane, bis(diethylamino)methoxyethylvinylsilane, bis(diethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane and other bis(dialkylamino)alkoxyalkylsilanes; bis(pyrrolidino)methylvinylsilane, bis(piperidino)methylvinylsilane, bis(hexamethyleneimino)methylvinylsilane, bis(4,5-dihydroimidazolyl)methylvinylsilane, bis(morpholino)methylvinylsilane and other bis(cyclic amino)alkylvinylsilane compounds, etc.

[0065] As X in the above general formula (1) 1 is a divalent hydrocarbon group, X 2 , X 3 and X 4Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) in the case where two of them are substituted amino groups include: bis(dimethylamino)methyl-4-vinylphenylsilane, bis(dimethylamino)methyl-3-vinylphenylsilane, bis(diethylamino)methyl-4-vinylphenylsilane, bis(diethylamino)methyl-3-vinylphenylsilane, bis(di-n-propylamino)methyl-4-vinylphenylsilane, bis(di-n-propylamino)methyl-3-vinylphenylsilane, bis(di-n-butylamino)methyl-4-vinylphenylsilane, bis(di-n-butylamino)methyl-3-vinylphenylsilane, bis(dimethylamino)ethyl-4-vinylphenylsilane, bis(dimethylamino)ethyl-3-vinylphenylsilane, bis(diethylamino)ethyl-4-vinylphenylsilane, bis(diethylamino)ethyl-3-vinylphenylsilane, bis(di-n-propylamino)ethyl-4-vinylphenylsilane, bis(di-n-propylamino)ethyl-3-vinylphenylsilane, bis(di-n-butylamino)ethyl-4-vinylphenylsilane, bis(di-n-butylamino)ethyl-3-vinylphenylsilane, etc., such as bis(dialkylamino)alkylvinylphenylsilane.

[0066] As X in the above general formula (1) 1 is a chemical single bond, X 2 , X 3 and X 4 Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) in the case where three of them are substituted amino groups include: tris(dimethylamino)vinylsilane, tris(diethylamino)vinylsilane, tris(di-n-propylamino)vinylsilane, tris(di-n-butylamino)vinylsilane, etc., such as tris(dialkylamino)vinylsilane.

[0067] As X in the above general formula (1) 1 is a divalent hydrocarbon group, X 2 , X 3 and X 4 Specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) in the case where three of them are substituted amino groups include: tris(dimethylamino)-4-vinylphenylsilane, tris(dimethylamino)-3-vinylphenylsilane, tris(diethylamino)-4-vinylphenylsilane, tris(diethylamino)-3-vinylphenylsilane, tris(di-n-propylamino)-4-vinylphenylsilane, tris(di-n-propylamino)-3-vinylphenylsilane, tris(di-n-butylamino)-4-vinylphenylsilane, tris(di-n-butylamino)-3-vinylphenylsilane, etc., such as tris(dialkylamino)vinylphenylsilane.

[0068] As X in the above general formula (1)1 is a chemical single bond, X 2 , X 3 and X 4 are not substituted amino groups, specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) include: trialkoxyvinylsilanes such as trimethoxyvinylsilane, triethoxyvinylsilane, and tripropoxyvinylsilane; dialkoxyalkylvinylsilanes such as methyldimethoxyvinylsilane and methyldiethoxyvinylsilane; dialkoxyarylvinylsilanes such as bis(tert-pentyloxy)phenylvinylsilane and bis(tert-butoxy)phenylvinylsilane; monoalkoxydialkylvinylsilanes such as dimethylmethoxyvinylsilane; monoalkoxydiarylvinylsilanes such as tert-butoxydiphenylvinylsilane and tert-pentyloxydiphenylvinylsilane; monoalkoxyalkylarylvinylsilanes such as tert-butoxymethylphenylvinylsilane and tert-butoxyethylphenylvinylsilane; substituted alkoxyvinylsilane compounds such as tris(β-methoxyethoxy)vinylsilane, etc.

[0069] Among the compounds represented by the above general formula (1), compounds in which X 1 is a chemical single bond are particularly preferred, and compounds in which X 1 is a chemical single bond and two of X 2 , X 3 and X 4 are substituted amino groups are more preferred, and compounds in which X 1 is a chemical single bond and two of X 2 , X 3 and X 4 are dialkylamino groups are particularly preferred.

[0070] Among the compounds represented by the above general formula (1), bis(dimethylamino)methylvinylsilane, bis(diethylamino)methylvinylsilane, and bis(di-n-butylamino)methylvinylsilane are particularly preferred, and bis(diethylamino)methylvinylsilane is especially preferred.

[0071] In addition, as vinyl compounds containing functional groups capable of interacting with silica other than the compounds represented by the above general formula (1), there can be mentioned: bis(trimethylsilyl)aminostyrenes such as 4-N,N-bis(trimethylsilyl)aminostyrene and 3-N,N-bis(trimethylsilyl)aminostyrene; bis(trimethylsilyl)aminoalkylstyrenes such as 4-bis(trimethylsilyl)aminomethylstyrene, 3-bis(trimethylsilyl)aminomethylstyrene, 4-bis(trimethylsilyl)aminoethylstyrene, and 3-bis(trimethylsilyl)aminoethylstyrene, etc.

[0072] Further, when using the compound represented by the above general formula (1) as a vinyl compound having a functional group capable of interacting with silica, a unit represented by the following general formula (3) is introduced into the conjugated diene polymer of the present invention as a unit of a vinyl compound having a functional group capable of interacting with silica.

[0073] [Chemical Formula 3]

[0074]

[0075] In the above general formula (3), X 5 represents a chemical single bond or a lower alkylene group, X 6 , X 7 and X 8 each independently represent a hydroxyl group, a substituted amino group, an alkoxy group, or a hydrocarbon group which may have a substituent.

[0076] Further, in the unit represented by the above general formula (3), X 5 corresponds to X 1 in the compound represented by the above general formula (1), and in the unit represented by the above general formula (3), X 6 , X 7 and X 8 correspond to X 2 , X 3 and X 4 in the compound represented by the above general formula (1), respectively. Therefore, in the unit represented by the above general formula (3), X 5 , X 6 , X 7 and X 8 can be the same as X 1 , X 2 , X 3 and X 4 in the compound represented by the above general formula (1), respectively. In addition, when using a compound in which at least one of X 2 , X 3 and X 4 is a substituted amino group or an alkoxy group as the compound represented by the above general formula (1), the substituted amino group or the alkoxy group can be hydrolyzed at any process and timing to make at least one of X 2 , X 3 and X 4 become a hydroxyl group.

[0077] In the conjugated diene polymer of the present invention, based on the total amount of all monomers being 100% by weight, the content ratio of the unit of the vinyl compound having a functional group capable of interacting with silica is preferably 0.001 to 10.000% by weight, more preferably 0.001 to 3.000% by weight. By making the content ratio of the unit of the vinyl compound having a functional group capable of interacting with silica within the above range, the processability of the conjugated diene polymer can be sufficient, and the fuel economy of the resulting rubber crosslinked product can be further improved.

[0078] In addition, the conjugated diene polymer of the present invention may further contain other monomer units in addition to the conjugated diene monomer unit, the aromatic vinyl monomer unit, and the unit of the vinyl compound having a functional group capable of interacting with silica. Examples of other compounds constituting such other monomer units include: chain olefin compounds such as ethylene, propylene, and 1-butene; cyclic olefin compounds such as cyclopentene and 2-norbornene; non-conjugated diene compounds such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene, etc.

[0079] In addition, the shrinkage factor of the high molecular weight fraction of the conjugated diene polymer of the present invention is 0.4 to 0.8, the adsorption rate of the high molecular weight fraction to silica is 75% or less, and the adsorption rate of the medium molecular weight fraction to silica is 40 to 100%.

[0080] Here, the low molecular weight fraction, the medium molecular weight fraction, and the high molecular weight fraction constituting the conjugated diene polymer of the present invention will be described. Hereinafter, the low molecular weight fraction is P_ LOW , the medium molecular weight fraction is P_ MID , the high molecular weight fraction is P_ HIGH , and the description will be made while referring to Figures 1 to 5 . In addition, Figures 1 to 5 FIG. is a graph schematically showing an example of a GPC chart obtained by gel permeation chromatography measurement of the conjugated diene polymer of the present invention using a styrene column.

[0081] First, the case where the conjugated diene polymer of the present invention has a single maximum value in the molecular weight distribution measured by gel permeation chromatography, that is, has a unimodal distribution as shown in Figure 1 (A) will be described.

[0082] As shown in Figure 1 (B), in the case of having a unimodal distribution, first, the molecular weight showing the maximum value of the molecular weight distribution is taken as the molecular weight Mp_ MID of the medium molecular weight fraction P_ MIDIn addition, the peak intensity S of the molecular weight showing a maximum with respect to the molecular weight distribution MID shows half the intensity (i.e., 1 / 2S MID ), and the molecular weight on the low molecular weight side of the molecular weight showing half the intensity is taken as the molecular weight Mp_ LOW of the low molecular weight species P_ LOW On the other hand, the peak intensity S of the molecular weight showing a maximum with respect to the molecular weight distribution MID shows half the intensity (i.e., 1 / 2S MID ), and the molecular weight on the high molecular weight side of the molecular weight showing half the intensity is taken as the molecular weight Mp_ HIGH of the high molecular weight species P_ HIGH .

[0083] In addition, Figure 2 (A) shows a mode having two maxima in the molecular weight distribution measured by gel permeation chromatography, i.e., a mode having a bimodal distribution. Here, Figure 2 (A) shows the following mode: a bimodal distribution, and in the two peaks including the maxima, the peak area on the low molecular weight side is larger than the peak area on the high molecular weight side.

[0084] As Figure 2 (B) shows, in the case of a mode having a bimodal distribution and a larger peak area on the low molecular weight side, in the peak on the low molecular weight side with a larger peak area, the molecular weight showing a maximum in the molecular weight distribution is taken as the molecular weight Mp_ MID of the medium molecular weight species P_ MID . In addition, in the peak on the high molecular weight side with a smaller peak area, the molecular weight showing a maximum in the molecular weight distribution is taken as the molecular weight Mp_ HIGH of the high molecular weight species P_ HIGH . Moreover, in the peak on the low molecular weight side with a larger peak area, the peak intensity S of the molecular weight showing a maximum with respect to the molecular weight distribution MID shows half the intensity (i.e., 1 / 2S MID ), and the molecular weight on the low molecular weight side of the molecular weight showing half the intensity is taken as the molecular weight Mp_ LOW of the low molecular weight species P_ LOW .

[0085] On the other hand, Figure 3 (A) shows a mode having two maxima in the molecular weight distribution measured by gel permeation chromatography, i.e., in a mode having a bimodal distribution, in the two peaks including the maxima, the peak area on the high molecular weight side is larger than the peak area on the low molecular weight side.

[0086] As Figure 3As shown in (B), in the case of a distribution having bimodality and with a larger peak area on the high molecular weight side, in the peak on the high molecular weight side with a large peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ MID of the medium molecular weight body P_ MID . Further, in the peak on the low molecular weight side with a small peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ LOW of the low molecular weight body P_ LOW . Moreover, in the peak on the high molecular weight side with a large peak area, the molecular weight on the high molecular weight side among the molecular weights at which the peak intensity S MID shows half of the intensity (i.e., 1 / 2S MID ) of the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ HIGH of the high molecular weight body P_ HIGH .

[0087] Further, Figure 4 (A) shows a mode having three maxima in the molecular weight distribution measured by gel permeation chromatography, that is, a mode having a trimodal distribution.

[0088] As Figure 4 shown in (B), in the case of a mode having a trimodal distribution, the molecular weights at which the three existing molecular weight distributions show maxima are taken as the molecular weight Mp_ LOW of the low molecular weight body P_ LOW , the molecular weight Mp_ MID of the medium molecular weight body P_ MID and the molecular weight Mp_ HIGH of the high molecular weight body P_ HIGH from the low molecular weight side.

[0089] Further, Figure 5 (A) shows a mode having four maxima in the molecular weight distribution measured by gel permeation chromatography, that is, a mode having a tetramodal distribution.

[0090] As Figure 5 shown in (B), in the case of a mode having a tetramodal distribution, among the four peaks showing four maxima, a combination of three consecutive peaks is selected, and the combination in which the sum of the peak areas of the three consecutive peaks becomes the largest is selected. In the mode shown in Figure 5 (B), a combination of three consecutive peaks including the peak on the highest molecular weight side is selected. Then, for the selected three consecutive peaks, from the low molecular weight side, the molecular weights at which the molecular weight distribution shows maxima are taken as the molecular weight Mp_ LOW of the low molecular weight body P_ LOW , the molecular weight Mp_ MID of the medium molecular weight body P_MID and high molecular weight polymer P_ HIGH with a molecular weight Mp_ HIGH . In addition, in Figure 5 (A), Figure 5 (B), a mode having four maxima, i.e., a distribution mode having four-peak property, is described. However, for a mode having five or more maxima, i.e., a distribution mode having five-peak property or more, a combination in which the sum of the peak areas of three consecutive peaks becomes the largest is also selected in the same manner, and the molecular weight Mp_ LOW of the low molecular weight polymer P_ LOW , the molecular weight Mp_ MID of the medium molecular weight polymer P_ MID and the molecular weight Mp_ HIGH of the high molecular weight polymer P_ HIGH are determined in the same manner.

[0091] The molecular weight Mp_ LOW of the low molecular weight polymer P_ LOW is preferably in the range of 50,000 to 200,000, more preferably in the range of 60,000 to 190,000, further preferably in the range of 60,000 to 180,000, and particularly preferably in the range of 70,000 to 160,000. By making the molecular weight Mp_ LOW of the low molecular weight polymer P_ LOW fall within the above range, the fuel economy of the obtained rubber crosslinked product can be made excellent, and the processability of the conjugated diene-based polymer can be further improved.

[0092] The molecular weight Mp_ MID of the medium molecular weight polymer P_ MID is preferably in the range of 210,000 to 600,000, more preferably in the range of 300,000 to 500,000, and further preferably in the range of 330,000 to 450,000. By making the molecular weight Mp_ MID of the medium molecular weight polymer P_ MID fall within the above range, the fuel economy of the obtained rubber crosslinked product can be made excellent, and the processability of the conjugated diene-based polymer can be further improved.

[0093] The molecular weight Mp_ HIGH of the high molecular weight polymer P_ HIGH is preferably in the range of 610,000 to 1,400,000, more preferably in the range of 700,000 to 1,300,000, and further preferably in the range of 740,000 to 1,200,000. By making the molecular weight Mp_ HIGH of the high molecular weight polymer P_ HIGH fall within the above range, good processability can be achieved, and the abrasion resistance and mechanical strength can be improved.

[0094] In addition, the overall weight-average molecular weight Mw_ of the conjugated diene polymer of the present invention TOTAL is preferably in the range of 300,000 to 900,000, more preferably in the range of 350,000 to 800,000, still more preferably in the range of 400,000 to 700,000, and particularly preferably in the range of 420,000 to 600,000. By making the overall weight-average molecular weight Mw_ of the conjugated diene polymer TOTAL fall within the above range, the fuel economy of the resulting rubber crosslinked product can be made excellent, and the processability of the conjugated diene polymer can be further improved.

[0095] The overall molecular weight distribution represented by the ratio (Mw / Mn) of the overall weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the conjugated diene polymer of the present invention is preferably 1.1 to 3.0, more preferably 1.2 to 2.5, and particularly preferably 1.2 to 2.2.

[0096] In addition, the above molecular weights can all be determined by gel permeation chromatography using a styrene column and obtained as values in terms of polystyrene conversion. Specifically, according to the above method described Figures 1 to 5 it is possible to obtain the molecular weight Mp_ of the low molecular weight fraction P_ LOW , the molecular weight Mp_ of the medium molecular weight fraction P_ LOW , and the molecular weight Mp_ of the high molecular weight fraction P_ MID . MID and the molecular weight Mp_ of the high molecular weight fraction P_ HIGH . HIGH .

[0097] In addition, as a method for making the molecular weight distribution of the conjugated diene polymer of the present invention have a distribution with bimodality or more, there is no particular limitation, and the following methods can be mentioned: when synthesizing a conjugated diene polymer by polymerizing monomers, a method of additionally adding a polymerization initiator in the middle of the polymerization; a method of performing a coupling reaction on the polymer chain obtained by polymerization, etc. In addition, at this time, for example, by selecting the timing of additionally adding the polymerization initiator, the amount of the additionally added polymerization initiator, the timing of performing the coupling reaction, the type of the coupling agent used, etc., it is possible to control the molecular weight Mp_ of the low molecular weight fraction P_ LOW , the molecular weight Mp_ of the medium molecular weight fraction P_ LOW , and the molecular weight Mp_ of the high molecular weight fraction P_ MID . MID and the molecular weight Mp_ of the high molecular weight fraction P_ HIGH . HIGH .

[0098] As the conjugated diene polymer of the present invention, from the viewpoint of further improving processability and fuel economy, as the molecular weight distribution, it preferably has a distribution with bimodality or more (having two or more peaks), and more preferably has a trimodal distribution (having three peaks). In addition, in the present invention, a value with an intensity three times or more that of the closest minimum value is defined as the maximum value, and the peak including such a maximum value is counted as the number of peaks. That is, even if a maximum value is shown, if the intensity relative to the closest minimum value is less than three times, it is not regarded as the maximum value forming a peak.

[0099] Moreover, the shrinkage factor of the high molecular weight fraction P_ HIGH of the conjugated diene polymer of the present invention is 0.4 to 0.8, and the adsorption rate of the high molecular weight fraction P_ HIGH of the conjugated diene polymer of the present invention to silica is 75% or less. Furthermore, the adsorption rate of the medium molecular weight fraction P_ MID of the conjugated diene polymer of the present invention to silica is 40 to 100%.

[0100] Here, the shrinkage factor of the high molecular weight fraction P_ HIGH is an index showing the degree of branching of the high molecular weight fraction P_ HIGH . Using tetrahydrofuran as a solvent, a GPC device (3D-GPC) equipped with a viscosity detector, a light scattering detector, and a differential refractive index (RI) detector can be used to measure the intrinsic viscosity [η] of the conjugated diene polymer, and the ratio of the measured intrinsic viscosity to the standard intrinsic viscosity [η]0 can be calculated. Specifically, 3D-GPC measurement can be performed on the conjugated diene polymer, and based on the measurement results, the intrinsic viscosity [η] at the molecular weight Mp_ HIGH of the high molecular weight fraction P_ HIGH can be obtained. According to the obtained intrinsic viscosity [η] and the standard intrinsic viscosity [η]0, the shrinkage factor is calculated as g' = [η] / [η]0. In addition, the standard intrinsic viscosity [η]0 is the calculated value of the intrinsic viscosity of the conjugated diene polymer without a branched structure (the intrinsic viscosity of a linear polymer), and there is a tendency that the lower the value of the shrinkage factor g', the higher the degree of branching.

[0101] Figure 6 An example of a graph showing the relationship between molecular weight and the intrinsic viscosity [η], standard intrinsic viscosity [η]0, and shrinkage factor g' measured by 3D-GPC is shown. In addition, Figure 6 a graph of the molecular weight distribution measured by GPC is also shown. As Figure 6 shown, by the molecular weight Mp_ HIGH of the high molecular weight fraction P_ HIGHThe intrinsic viscosity [η] measured by 3D-GPC under the following conditions and the standard intrinsic viscosity [η]0 are used to calculate their ratio (η / η0), and the high molecular weight component P_ HIGH is obtained.

[0102] In the conjugated diene polymer of the present invention, the shrinkage factor of the high molecular weight component P_ HIGH is in the range of 0.4 to 0.8, preferably 0.4 to 0.7, and more preferably 0.4 to 0.6. When the shrinkage factor of the high molecular weight component P_ HIGH is too low, the mechanical strength is poor. On the other hand, when the shrinkage factor of the high molecular weight component P_ HIGH is too high, the processability is reduced. In addition, as a method for making the shrinkage factor of the high molecular weight component P_ HIGH fall within the above range, there is no particular limitation, and examples thereof include a method of subjecting the polymer chain obtained by polymerization to a coupling reaction using a coupling agent having three or more functional groups.

[0103] In addition, the shrinkage factor of the medium molecular weight component P_ MID in the conjugated diene polymer of the present invention can also be obtained in the same manner as the shrinkage factor of the high molecular weight component P_ HIGH by calculating the ratio (η / η0) of the intrinsic viscosity [η] measured by 3D-GPC under the following conditions and the standard intrinsic viscosity [η]0 based on the molecular weight Mp_ MID of the medium molecular weight component P_ HIGH . The shrinkage factor of the medium molecular weight component P_ MID is not particularly limited, preferably 0.8 to 1.2, more preferably 0.8 to 1.0, and further preferably 0.8 to 0.9. By making the shrinkage factor of the medium molecular weight component P_ MID fall within the above range, the processability can be further improved.

[0104] In addition, the adsorption rates of the high molecular weight component P_ HIGH and the medium molecular weight component P_ MID of the conjugated diene polymer of the present invention are within a specific range. That is, the adsorption rate of the high molecular weight component P_ HIGH of the conjugated diene polymer of the present invention to silica is 75% or less, and the adsorption rate of the medium molecular weight component P_ MID to silica is in the range of 40 to 100%. In addition, in the present invention, the adsorption rates of the high molecular weight component P_ HIGH and the medium molecular weight component P_ MID to silica can be obtained, for example, by performing GPC measurements using a styrene-based column and a silica-based column on the conjugated diene polymer and calculating based on these results according to the following formula (1).

[0105] Adsorption rate to silica (%) = (1 - (area A of this material measured by GPC using a silica-based column Si / area B of standard polystyrene measured by GPC using a silica-based column Si )) × (area B of standard polystyrene measured by GPC using a styrene-based column sty / area A of this material measured by GPC using a styrene-based column sty )) × 100 (1)

[0106] Herein, Figure 7 is a graph schematically showing the GPC measurement results obtained using a styrene-based column and a silica-based column. As Figure 7 shown, in the GPC measurement using a styrene-based column, no adsorption or the like occurred. On the other hand, in the GPC measurement using a silica-based column, a part of the polymer chain was adsorbed to silica, and thus these results were different. In the present invention, the adsorption rate of the high molecular weight body P_ HIGH to silica and the adsorption rate of the medium molecular weight body P_ MID to silica are defined.

[0107] In addition, the GPC measurement using a styrene column can be measured in the following manner: using a standard polystyrene with a molecular weight of 5000, using two Plus Pore series Poly Pore (7.5mm ID×300mm, manufactured by Agilent Technologies) as columns, using a column oven (CTO-20A, manufactured by Shimadzu Corporation) and an RI detector (RID-10A, manufactured by Shimadzu Corporation) at a temperature of 35°C, using a mixed solution of tetrahydrofuran and 2-(ethylamino)ethanol as a mobile phase, and measuring at a flow rate of 1.0 mL / min. As a column, a column connecting three PLgel Mini MIXED-C (4.6mm ID×250mm, manufactured by Agilent Technologies) or a column connecting three PLgel MIXED-C (7.5mm ID×300mm, manufactured by Agilent Technologies) can also be used. In addition, GPC measurement using a silica column can be measured in the following manner: using standard polystyrene with a molecular weight of 5000, using a total of three columns, namely, one Zorbax PSM1000-S (6.2×250 mm, manufactured by Agilent Technologies Inc.), one Zorbax PSM-300 (6.2×250 mm, manufactured by Agilent Technologies Inc.), and one Zorbax PSM60-S (6.2×250 mm, manufactured by Agilent Technologies Inc.) as columns, using a column oven (CTO-20A, manufactured by Shimadzu Corporation) and an RI detector (RID-10A, manufactured by Shimadzu Corporation) at a temperature of 35°C, using tetrahydrofuran as the mobile phase, and measuring at a flow rate of 0.7 mL / min.

[0108] And, specifically, the high molecular weight body P_ HIGH Adsorption rate of silica and medium molecular weight P_ MID The adsorption rate of silica was determined as follows.

[0109] That is, Figure 1 As shown in (A), when the conjugated diene polymer of the present invention has a unimodal distribution, the medium molecular weight body P_ MID The adsorption rate of silica is Figure 1 (B) Mp_ LOW With Mp_ HIGH The area between is taken as the object of measurement. Specifically, the medium molecular weight body P_ MID The adsorption rate of silica can be calculated as follows: Figure 1 (B) Mp_ LOW With Mp_ HIGH The area between Si , A sty(i.e., the area A between Mp_ LOW and Mp_ HIGH measured by GPC using a silica-based column, and the area A between Mp_ Si and Mp_ LOW measured by GPC using a styrene-based column (both of these areas)), using the obtained areas A HIGH and A sty , is calculated by the above formula (1). In addition, the adsorption rate of the high molecular weight polymer P_ Si to silica is determined by taking the area between Mp_ sty and Mp HIGH shown in Figure 1 (B) (where Mp HIGH is the molecular weight on the high molecular weight side among the molecular weights showing a strength of 1 / 100 of the maximum intensity (S _1％_HIGH in _1％_HIGH (B))) as the object of measurement. Specifically, the adsorption rate of the high molecular weight polymer P_ MID to silica can be calculated as follows: The areas A HIGH and A HIGH between Mp_ _1％_HIGH shown in Figure 1 and Mp Si are respectively obtained, and using the obtained areas A sty and A Si , the calculation is performed by the above formula (1).

[0110] In addition, as shown in Figure 2 (A), in the case of a bimodal distribution where the peak area on the low molecular weight side is larger, the adsorption rate of the medium molecular weight polymer P_ sty to silica can be calculated as follows: The areas A MID and A LOW between Mp_ 谷 shown in Figure 2 and Mp_ 谷 (where Mp_ MID is the molecular weight showing the minimum value between Mp_ HIGH and Mp_ Si ) are respectively obtained, and using the obtained areas A sty and A Si , the calculation is performed by the above formula (1). In addition, the adsorption rate of the high molecular weight polymer P_ sty to silica can be calculated as follows: The areas A HIGH and A 谷 between Mp_ _1％_HIGH shown in Figure 2 and Mp _1％_HIGH (where Mp MIDTo show the area A between the molecular weights on the high molecular weight side in the molecular weight of the intensity that is 1 / 100 of the maximum intensity (S in (B)) Figure 2 (in (B) is S MID ), the calculated area A Si 、A sty is calculated by the above formula (1) using the obtained areas A Si 、A sty .

[0111] In addition, as shown in (A), in the case of a bimodal distribution where the peak area on the high molecular weight side is larger, the adsorption rate of the medium molecular weight body P Figure 3 to silica can be calculated as follows: The areas A MID between Mp Figure 3 (shown in (B)) (Mp 谷 (Mp 谷 is the molecular weight showing the minimum value between Mp LOW and Mp MID ) and Mp HIGH are respectively obtained, and the adsorption rate of the high molecular weight body P Si 、A sty is calculated by the above formula (1) using the obtained areas A Si 、A sty . In addition, the adsorption rate of the high molecular weight body P HIGH to silica can be calculated as follows: The areas A Figure 3 between Mp HIGH and Mp _1％_HIGH (Mp _1％_HIGH is to show the molecular weight of the intensity that is 1 / 100 of the maximum intensity (S in (B)) Figure 3 (in (B) is S MID ) on the high molecular weight side) are respectively obtained, and the adsorption rate is calculated by the above formula (1) using the obtained areas A Si 、A sty 、A Si 、A sty .

[0112] In addition, as shown in (A), in the case of a trimodal distribution, the adsorption rate of the medium molecular weight body P Figure 4 to silica can be calculated as follows: The areas A MID between Mp Figure 4 (shown in (B)) (Mp _谷_1 (Mp _谷_1 is the molecular weight showing the minimum value between Mp LOW and Mp MID ) and Mp _谷_2 (Mp _谷_2 is the molecular weight showing the minimum value between Mp MID and MpHIGH the area A between the minimum molecular weight) Si and A sty , using the obtained area A Si and A sty , calculated by the above formula (1). In addition, the adsorption rate of the high molecular weight polymer P_ HIGH to silica can be calculated as follows: separately obtain Figure 4 Mp shown in (B) _谷_2 and Mp _1％_HIGH (Mp _1％_HIGH is the molecular weight on the high molecular side among the molecular weights of the intensity that is 1 / 100 of the maximum intensity (S in (B)) Figure 4 ) the area A between MID ) Si and A sty , using the obtained area A Si and A sty , calculated by the above formula (1).

[0113] In addition, as Figure 5 (A) shows, in the case of a distribution with four peaks, the adsorption rate of the medium molecular weight polymer P_ MID to silica can be calculated as follows: separately obtain Figure 5 Mp shown in (B) _谷_2 (Mp _谷_2 is the molecular weight showing the minimum value between Mp_ LOW and Mp_ MID ) and Mp _谷_3 (Mp _谷_3 is the molecular weight showing the minimum value between Mp_ MID and Mp_ HIGH ) the area A between Si and A sty , using the obtained area A Si and A sty , calculated by the above formula (1). In addition, the adsorption rate of the high molecular weight polymer P_ HIGH to silica can be calculated as follows: separately obtain Figure 5 Mp shown in (B) _谷_3 and Mp _1％_HIGH (Mp _1％_HIGH is the molecular weight on the high molecular side among the molecular weights of the intensity that is 1 / 100 of the maximum intensity (S in (B)) Figure 5 ) the area A between MID ) Si and A sty , using the obtained area A Si and A sty, calculated by the above formula (1). In addition, for a mode having five or more maxima, that is, a distribution having pentapeakedness or more, it can be carried out in the same manner as in the case of a distribution having quadripeakedness, and the medium molecular weight body P_ MID The adsorption rate to silica and the high molecular weight body P_ HIGH The adsorption rate to silica. Here, in any mode, the molecular weight range for calculating the area is measured using a styrene-based column, and in the GPC chart measured using a silica-based column, the range of the molecular weight determined by the styrene-based column is also used to calculate the area. In addition, the area can be calculated by confirming the elution time showing each of the above molecular weights and integrating the elution time to calculate the area, and thus carried out.

[0114] High molecular weight body P_ HIGH The adsorption rate to silica is 75% or less, preferably 10 - 70%, more preferably 10 - 60%. When the adsorption rate of the high molecular weight body P_ HIGH to silica is too high, the processability decreases. As a method for making the adsorption rate of the high molecular weight body P_ HIGH to silica within the above range, there is no particular limitation, and examples include a method of adjusting the amount and type of units of a vinyl compound containing a functional group capable of interacting with silica contained in the high molecular weight body P_ HIGH and the like.

[0115] In addition, the adsorption rate of the medium molecular weight body P_ MID to silica is 40 - 100%, preferably 50 - 100%, more preferably 50 - 80%. When the adsorption rate of the medium molecular weight body P_ MID to silica is too low, the effect of improving fuel economy cannot be obtained. As a method for making the adsorption rate of the medium molecular weight body P_ MID to silica within the above range, there is no particular limitation, and examples include a method of adjusting the amount and type of units of a vinyl compound containing a functional group capable of interacting with silica contained in the medium molecular weight body P_ MID and the like.

[0116] In addition, in the conjugated diene polymer of the present invention, the content ratios of the low molecular weight body P_ LOW , the medium molecular weight body P_ MID and the high molecular weight body P_ HIGH are not particularly limited. The content ratio of the low molecular weight body P_ LOW is preferably 5 - 20% by weight, more preferably 8 - 17% by weight, the content ratio of the medium molecular weight body P_ MID is preferably 30 - 70% by weight, more preferably 50 - 60% by weight, and the content ratio of the high molecular weight body P_ HIGHThe content ratio is preferably 20 to 60% by weight, more preferably 25 to 40% by weight. In addition, the content ratio of the low molecular weight body P_ LOW , the medium molecular weight body P_ MID and the high molecular weight body P_ HIGH can be obtained by the following method.

[0117] That is, as shown in Figure 1 (A), when the conjugated diene polymer of the present invention has a unimodal distribution, the content ratio of the low molecular weight body P_ LOW is obtained by taking the area between Mp _1％_LOW (Mp _1％_LOW is the molecular weight on the low molecular side among the molecular weights showing 1 / 100 of the maximum intensity (S Figure 1 in MID )(B)) and Mp_ Figure 1 (B) shown in LOW as the area of the low molecular weight body P_ LOW . In addition, the content ratio of the medium molecular weight body P_ MID is obtained by taking the area between Figure 1 (B) shown Mp_ LOW and Mp_ HIGH as the area of the medium molecular weight body P_ MID . Moreover, the content ratio of the high molecular weight body P_ HIGH is obtained by taking the area between Figure 1 (B) shown Mp_ HIGH and Mp _1％_HIGH as the area of the high molecular weight body P_ HIGH .

[0118] As shown in Figure 2 (A), in the case of a bimodal distribution and the peak area on the low molecular weight side is larger, the content ratio of the low molecular weight body P_ LOW is obtained by taking the area between Mp _1％_LOW (Mp _1％_LOW is the molecular weight on the low molecular side among the molecular weights showing 1 / 100 of the maximum intensity (S Figure 2 in MID )(B)) and Mp_ Figure 2 (B) shown Mp_ LOW as the area of the low molecular weight body P_ LOW . In addition, the content ratio of the medium molecular weight body P_ MID is obtained by taking the area between Figure 2 (B) shown Mp_ LOW and Mp_ 谷 as the area of the medium molecular weight body P_ MIDis obtained from the area. Furthermore, the content ratio of the high molecular weight polymer P_ HIGH is determined by taking the area between Figure 2 Mp_ shown in (B) 谷 and Mp _1％_HIGH as the area of the high molecular weight polymer P_ HIGH and calculating it.

[0119] As Figure 3 (A) shows, in the case of a bimodal distribution with a larger peak area on the high molecular weight side, the content ratio of the low molecular weight polymer P_ LOW is determined by taking the area between Mp _1％_LOW (where Mp _1％_LOW is the molecular weight corresponding to 1 / 100 of the maximum intensity (S in Figure 3 (B)) and located on the low molecular weight side) and MID Mp_ shown in (B) Figure 3 as the area of the low molecular weight polymer P_ 谷 and calculating it. In addition, the content ratio of the medium molecular weight polymer P_ LOW is determined by taking the area between MID Mp_ shown in (B) Figure 3 and Mp_ 谷 as the area of the medium molecular weight polymer P_ HIGH and calculating it. Moreover, the content ratio of the high molecular weight polymer P_ MID is determined by taking the area between HIGH Mp_ shown in (B) Figure 3 and Mp HIGH as the area of the high molecular weight polymer P_ _1％_HIGH and calculating it. HIGH

[0120] As Figure 4 (A) shows, in the case of a trimodal distribution, the content ratio of the low molecular weight polymer P_ LOW is determined by taking the area between Mp _1％_LOW (where Mp _1％_LOW is the molecular weight corresponding to 1 / 100 of the maximum intensity (S in Figure 4 (B)) and located on the low molecular weight side) and MID Mp shown in (B) Figure 4 as the area of the low molecular weight polymer P_ _谷_1 and calculating it. In addition, the content ratio of the medium molecular weight polymer P_ LOW is determined by taking the area between MID Mp shown in (B) Figure 4 and Mp _谷_1 as the area of the medium molecular weight polymer P_ _谷_2 and calculating it. MID ​is obtained by the area. Furthermore, the content ratio of the high molecular weight polymer P_ HIGH is obtained by taking the area between Mp shown in Figure 4 (B) and Mp _谷_2 as the area of the high molecular weight polymer P_ _1％_HIGH . HIGH is obtained.

[0121] As Figure 5 (A) shows, in the case of a distribution having four peaks, the content ratio of the low molecular weight polymer P_ LOW is obtained by taking the area between Mp _1％_LOW (Mp _1％_LOW is the molecular weight on the low molecular side in the molecular weight having a strength of 1 / 100 of the maximum intensity (S in Figure 5 (B)) and Mp shown in MID ) as the area of the low molecular weight polymer P_ Figure 5 (B) and Mp _谷_2 . Furthermore, the content ratio of the medium molecular weight polymer P_ LOW is obtained by taking the area between Mp shown in MID Figure 5 and Mp (B) and Mp _谷_2 as the area of the medium molecular weight polymer P_ _谷_3 . Moreover, the content ratio of the high molecular weight polymer P_ MID is obtained by taking the area between Mp shown in HIGH Figure 5 and Mp (B) and Mp _谷_3 as the area of the high molecular weight polymer P_ _1％_HIGH . In addition, in this case, the area can also be calculated by confirming the elution time showing each of the above molecular weights and integrating the elution time to calculate the area. HIGH Thus, it is carried out.

[0122] The vinyl bond content in the conjugated diene monomer units (e.g., isoprene monomer units and 1,3-butadiene monomer units) in the whole conjugated diene-based polymer of the present invention is preferably 1 to 90% by weight, more preferably 3 to 85% by weight, and particularly preferably 5 to 80% by weight. By making the vinyl bond content in the conjugated diene monomer units in the whole conjugated diene-based polymer within the above range, fuel economy can be made more excellent.

[0123] Furthermore, the Mooney viscosity (ML 1+4 , 100 °C) of the conjugated diene-based polymer of the present invention is preferably 20 to 100, more preferably 30 to 90, and particularly preferably 35 to 80. In addition, when the conjugated diene-based polymer is made into an oil-extended rubber, it is preferable that the Mooney viscosity of the oil-extended rubber is within the above range.

[0124] The glass transition temperature (Tg) of the conjugated diene polymer of the present invention is not particularly limited, and is preferably 20 to -110 °C, more preferably 10 °C to -70 °C. The glass transition temperature of the conjugated diene rubber used in the present invention can be appropriately adjusted, for example, by adjusting the content of the aromatic vinyl monomer unit in the conjugated diene polymer and the vinyl bond content in the conjugated diene monomer unit.

[0125] <Manufacturing method of conjugated diene polymer>

[0126] The manufacturing method of the conjugated diene polymer of the present invention includes the following steps: a first step of polymerizing a monomer containing a conjugated diene compound in an inert solvent in the presence of a polymerization initiator to obtain a solution containing a polymer chain having a living end; a second step of subjecting a part of the polymer chain having a living end obtained in the first step to a coupling reaction to form a coupled polymer chain and obtain a solution containing the coupled polymer chain and the polymer chain having a living end; and a third step of further polymerizing a monomer containing a conjugated diene compound with the polymer chain having a living end after the coupling reaction in the second step. In at least one of the first step and the third step, as the monomer for polymerization, a monomer containing a conjugated diene compound and a vinyl compound is used, and the vinyl compound is a vinyl compound containing a functional group capable of interacting with silica.

[0127] The first step is the following step: polymerizing a monomer containing a conjugated diene compound in an inert solvent in the presence of a polymerization initiator to obtain a solution containing a polymer chain having a living end.

[0128] The inert solvent for polymerization is not particularly limited as long as it is an inert solvent commonly used in solution polymerization and does not hinder the polymerization reaction. Specific examples of the inert solvent include: chain or branched aliphatic hydrocarbons such as propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, propylene, 1-butene, isobutene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, n-heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane; aromatic hydrocarbons such as benzene, ethylbenzene, toluene, xylene; ether compounds such as tetrahydrofuran, diethyl ether. These inert solvents can be used alone or in combination of two or more. The amount of the inert solvent is not particularly limited. For example, it is an amount such that the monomer concentration becomes 1 to 50% by weight, preferably an amount such that the monomer concentration becomes 5 to 40% by weight.

[0129] As a polymerization initiator for polymerization, there is no particular limitation as long as it is a polymerization initiator capable of polymerizing a monomer containing a conjugated diene compound to impart a conjugated diene polymer chain having an active end. Specific examples thereof include polymerization initiators using an organic alkali metal compound, an organic alkaline earth metal compound, a lanthanide metal compound, etc. as a main catalyst. Examples of the organic alkali metal compound include: organic monolithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, ethyllithium, n-propyllithium, isopropyllithium, tert-octyllithium, n-decyllithium, 2-naphthyllithium, 2-butylphenyllithium, 4-phenylbutyllithium, hexyllithium, cyclopentyllithium, the reaction product of diisopropenylbenzene and butyllithium, stilbenelithium, etc.; organic poly-lithium compounds such as dilithio methane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, 1,3,5-tris(lithiummethyl)benzene, the reaction product of sec-butyllithium and diisopropenylbenzene, the reaction product of n-butyllithium, 1,3-butadiene and divinylbenzene, the reaction product of n-butyllithium and a polyacetylene compound, etc.; organic sodium compounds such as sodium naphthalene; organic potassium compounds such as potassium naphthalene; organic rubidium compounds; organic cesium compounds, etc. In addition, alcoholates, sulfonates, carbonates, amides, etc. of lithium, sodium, potassium, etc. can also be cited. In addition, it can also be used in combination with other organic metal compounds. Furthermore, known organic alkali metal compounds disclosed in, for example, U.S. Patent No. 5708092, British Patent No. 2241239, U.S. Patent No. 5527753, etc. can also be used.

[0130] The amount of the polymerization initiator is not particularly limited, and is generally in the range of 1 to 50 millimoles, preferably in the range of 1.2 to 20 millimoles, and more preferably in the range of 2 to 15 millimoles, relative to 1000 g of the monomer.

[0131] The polymerization temperature is generally in the range of -80 to +150 °C, preferably in the range of 0 to 100 °C, and more preferably in the range of 30 to 90 °C. As the polymerization method, any method such as batchwise and continuous can be adopted. In the case of copolymerizing a conjugated diene compound and an aromatic vinyl compound, from the aspect of easily controlling the randomness of the bonding of the conjugated diene monomer unit and the aromatic vinyl monomer unit, the batchwise method is preferred. In addition, the bonding mode of each monomer can be various bonding modes such as block, cone, and random. Among these, the random mode is preferred. By being in the random mode, the low heat generation property of the obtained rubber crosslinked product can be further improved.

[0132] In addition, when polymerizing monomers containing a conjugated diene compound, in order to adjust the vinyl bond content in the conjugated diene monomer units in the obtained conjugated diene-based polymer chain, a polar compound can also be added to the non-reactive organic solvent. As the polar compound, for example, an ether compound, a tertiary amine, a phosphine compound, an alkali metal alcoholate, an alkali metal phenolate, etc. can be used. As the ether compound, for example, cyclic ethers such as tetrahydrofuran, tetrahydropyran, 1,4-dioxane; aliphatic monoethers such as diethyl ether, dibutyl ether; aliphatic diethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether; aliphatic triethers such as diethylene glycol diethyl ether, diethylene glycol dibutyl ether; aromatic ethers such as diphenyl ether, anisole, 1,2-dimethoxybenzene, 3,4-dimethoxytoluene, etc. can be cited. As the tertiary amine, for example, triethylamine, tripropylamine, tributylamine, 1,1,2,2-tetramethylethylenediamine, N,N-diethylaniline, pyridine, quinoline, etc. can be cited. As the phosphine compound, for example, trimethylphosphine, triethylphosphine, triphenylphosphine, etc. can be cited. As the alkali metal alcoholate, for example, sodium tert-butoxide, potassium tert-butoxide, sodium tert-pentoxide, potassium tert-pentoxide, etc. can be cited. As the alkali metal phenolate, for example, sodium phenoxide, potassium phenoxide, etc. can be cited. These polar compounds can be used alone or in combination of two or more. The amount of the polar compound used can be determined as long as it is based on the target vinyl bond content. Preferably, it is 0.001 to 100 moles, more preferably 0.01 to 10 moles, relative to 1 mole of the polymerization initiator. When the amount of the polar compound used is within this range, the adjustment of the vinyl bond content in the conjugated diene monomer units is easy, and there is also little adverse effect caused by the inactivation of the polymerization initiator. Alkanes and other cyclic ethers; aliphatic monoethers such as diethyl ether and dibutyl ether; aliphatic diethers such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, and ethylene glycol dibutyl ether; aliphatic triethers such as diethylene glycol diethyl ether and diethylene glycol dibutyl ether; aromatic ethers such as diphenyl ether, anisole, 1,2-dimethoxybenzene, and 3,4-dimethoxytoluene. As the tertiary amine, for example, triethylamine, tripropylamine, tributylamine, 1,1,2,2-tetramethylethylenediamine, N,N-diethylaniline, pyridine, quinoline, etc. can be cited. As the phosphine compound, for example, trimethylphosphine, triethylphosphine, triphenylphosphine, etc. can be cited. As the alkali metal alcoholate, for example, sodium tert-butoxide, potassium tert-butoxide, sodium tert-pentoxide, potassium tert-pentoxide, etc. can be cited. As the alkali metal phenolate, for example, sodium phenoxide, potassium phenoxide, etc. can be cited. These polar compounds can be used alone or in combination of two or more. The amount of the polar compound used can be determined as long as it is based on the target vinyl bond content. Preferably, it is 0.001 to 100 moles, more preferably 0.01 to 10 moles, relative to 1 mole of the polymerization initiator. When the amount of the polar compound used is within this range, the adjustment of the vinyl bond content in the conjugated diene monomer units is easy, and there is also little adverse effect caused by the inactivation of the polymerization initiator.

[0133] In addition, in the first step, it is sufficient to use at least a monomer containing a conjugated diene compound as the monomer for polymerization. From the viewpoint of making the conjugated diene-based polymer a polymer having a conjugated diene monomer unit and an aromatic vinyl monomer unit, a monomer containing an aromatic vinyl compound is preferred. Furthermore, as the monomer for polymerization, a monomer containing a vinyl compound having a functional group capable of interacting with silica can also be used. From the viewpoint of further improving the processability of the conjugated diene-based polymer, it is preferred not to use a vinyl compound having a functional group capable of interacting with silica in the first step, and to use a vinyl compound having a functional group capable of interacting with silica in the third step described later.

[0134] The second step is the following step: A coupling reaction is carried out on a part of the polymer chain having a living end obtained in the first step, thereby forming a coupled polymer chain, and a solution containing the coupled polymer chain and the polymer chain having a living end is obtained.

[0135] As the coupling agent, there is no particular limitation, and examples thereof include silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, tin tetrachloride, methyltin trichloride, dimethylditin dichloride, trimethyltin chloride, tetramethoxysilane, methyltrimethoxysilane, dimethoxydimethylsilane, methyltriethoxysilane, ethyltrimethoxysilane, dimethoxydiethylsilane, diethoxydimethylsilane, tetraethoxysilane, ethyltriethoxysilane, diethoxydiethylsilane, bis(trichlorosilyl)methane, 1,2-bis(trichlorosilyl)ethane, 1,3-bis(trichlorosilyl)propane, 1,4-bis(trichlorosilyl)butane, 1,5-bis(trichlorosilyl)pentane, 1,6-bis(trichlorosilyl)hexane, etc. Among these, from the viewpoint that the shrinkage factor of the high molecular weight body P_ HIGH contained in the obtained conjugated diene-based polymer can be within a specific range, the reduction in processability caused by high molecular weight can be well suppressed, and the mechanical properties can be appropriately improved, a coupling agent having three or more functional groups is preferably used, and a coupling agent having four or more functional groups is more preferably used.

[0136] The amount of the coupling agent used is not particularly limited. From the viewpoint of only subjecting a part of the polymer chains having active ends obtained in the first step to a coupling reaction, in terms of the functional groups of the coupling agent, it is preferably less than 1 mole, more preferably 0.03 to 0.4 mole, and further preferably 0.05 to 0.3 mole, relative to 1 mole of the polymerization initiator used in the first step. By making the amount of the coupling agent within the above range, fuel economy can be further improved. By adding the coupling agent, the polymer chains having active ends undergo a coupling reaction at the active ends. As a result, the active ends of the polymer chains after the coupling reaction disappear, and the polymer chains become those without active ends.

[0137] The third step is the following step: after the above coupling reaction is carried out in the second step, the monomer containing a conjugated diene compound is further polymerized with the polymer chains having active ends.

[0138] In the third step, as the monomer used, it is sufficient to use a monomer containing at least a conjugated diene compound. From the viewpoint of making the conjugated diene polymer into a polymer having a conjugated diene monomer unit and an aromatic vinyl monomer unit, a monomer containing an aromatic vinyl compound is preferred. Further, in the third step, as the monomer for polymerization, a monomer containing a vinyl compound having a functional group capable of interacting with silica is preferably included. In the third step, by using a vinyl compound having a functional group capable of interacting with silica, it is possible to preferentially introduce a unit of a vinyl compound having a functional group capable of interacting with silica into polymer chains other than the polymer chains that have undergone a coupling reaction in the second step. Moreover, thereby, it is possible to effectively increase the adsorption rate of polymer chains other than the polymer chains that have undergone a coupling reaction to silica. As a result, it is possible to further improve fuel economy while maintaining good processability.

[0139] In addition, the polymerization in the third step may be carried out in an inert solvent. The inert solvent is not particularly limited, and the same solvent as the inert solvent exemplified in the first step above can be used. The polymerization temperature and the polymerization method are also not particularly limited, and the same as those in the first step above. In addition, the bonding mode of each monomer can be various bonding modes such as block-like, conical, and random. Among these, a random mode is preferred. By being random, the low heat generation property of the obtained rubber crosslinked product can be further improved.

[0140] Further, in the production method of the present invention, it is preferred to additionally add a polymerization initiator at any time during the polymerization in the first step, or at the start of the polymerization in the third step and during the polymerization in the third step. The timing of additionally adding the polymerization initiator and the number of times of additionally adding the polymerization initiator are not particularly limited, and can be determined according to the molecular weight distribution of the conjugated diene polymer desired to be obtained. In the production method of the present invention, it is preferred to additionally add a polymerization initiator at any time during the polymerization in the first step, or at the start of the polymerization in the third step and during the polymerization in the third step. However, it is preferred to additionally add the polymerization initiator at the start of the polymerization in the third step and during the polymerization in the third step. The amount of the additionally added polymerization initiator is not particularly limited, and is preferably 0.1 to 0.7 mol, more preferably 0.2 to 0.6 mol, relative to 1 mol of the polymerization initiator used at the start of the polymerization.

[0141] In addition, the above-mentioned first step, second step, and third step are preferably carried out as continuous steps. For example, the following method is preferred: while continuing the polymerization reaction in the first step, the coupling reaction caused by the addition of the coupling agent in the second step is carried out, and then the polymerization reaction in the third step is carried out.

[0142] Moreover, after the polymerization reaction of the third step is completed, by adding an alcohol such as methanol, ethanol, and isopropyl alcohol or a polymerization terminator such as water into the polymerization system, the active terminal is deactivated, whereby a solution of a conjugated diene polymer can be obtained.

[0143] If desired, an antioxidant such as a phenolic stabilizer, a phosphorus stabilizer, and a sulfur stabilizer, a granulating agent, and a scale inhibitor are added to the solution of the conjugated diene polymer obtained as described above, and then the polymerization solvent is separated from the reaction solution by direct drying or stripping, etc., and a solid conjugated diene rubber is recovered from the reaction solution. Further, if desired, a filling oil is compounded to prepare an oil-extended rubber from the conjugated diene polymer. Examples of the filling oil include paraffinic, aromatic, and naphthenic petroleum softeners, vegetable softeners, and fatty acids. When a petroleum softener is used, it is preferred that the content of polycyclic aromatics extracted by the method of IP346 (inspection method of the Institute of Petroleum, UK) is less than 3%. When a filling oil is used, its amount is usually 5 to 100 parts by weight relative to 100 parts by weight of the conjugated diene polymer.

[0144] In addition, examples of the phenolic stabilizer added to the solution of the conjugated diene polymer of the present invention include: 1'-hydroxy[2,2'-ethylidenebis[4,6-bis(1,1-dimethylpropyl)benzene]]-1-acrylate, 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate, 2,6-di-tert-butyl-p-cresol, pentaerythritol tetra[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, 4,6-bis(octylthiomethyl)-o-cresol, etc. Examples of the sulfur stabilizer include: dilauryl 3,3'-thiodipropionate, bis[3-(dodecylthio)propionic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediol ester, ditridecyl 3,3'-thiodipropionate, etc. Examples of the phosphorus stabilizer include tris(2,4-di-tert-butylphenyl) phosphite, etc.

[0145] The stabilizer can be used alone or in combination of two or more. For example, phenolic stabilizers and other stabilizers can be used in combination. As a combination of two stabilizers, examples include: the combination of 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester; the combination of 1'-hydroxy[2,2'-ethylidenebis[4,6-bis(1,1-dimethylpropyl)benzene]]-1-acrylate and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester; the combination of 4,6-bis(octylthiomethyl)-o-cresol and 2,6-di-tert-butyl-p-cresol; the combination of 4,6-bis(octylthiomethyl)-o-cresol and 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate; the combination of 4,6-bis(octylthiomethyl)-o-cresol and 1'-hydroxy[2,2'-ethylidenebis[4,6-bis(1,1-dimethylpropyl)benzene]]-1-acrylate; the combination of 4,6-bis(octylthiomethyl)-o-cresol and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester; the combination of 4,6-bis(octylthiomethyl)-o-cresol and didodecyl 3,3'-thiodipropionate, etc.

[0146] As a combination of three stabilizers, examples include: the combination of 4,6-bis(octylthiomethyl)-o-cresol, 1'-hydroxy[2,2'-ethylidenebis[4,6-bis(1,1-dimethylpropyl)benzene]]-1-acrylate and didodecyl 3,3'-thiodipropionate; the combination of 4,6-bis(octylthiomethyl)-o-cresol, 2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl acrylate and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester; the combination of 4,6-bis(octylthiomethyl)-o-cresol, 2,6-di-tert-butyl-p-cresol and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester; the combination of 4,6-bis(octylthiomethyl)-o-cresol, 1'-hydroxy[2,2'-ethylidenebis[4,6-bis(1,1-dimethylpropyl)benzene]]-1-acrylate and bis[3-(dodecylthio)propanoic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediyl ester, etc.

[0147] Furthermore, from the viewpoint of further improving the affinity for fillers such as silica, the polymer chain ends of the conjugated diene polymer of the present invention can be modified with a heteroatom-containing functional group. As the heteroatom-containing functional group, there is no particular limitation as long as it is a group containing a heteroatom. As the heteroatom, a group containing at least one selected from a nitrogen atom, an oxygen atom, and a silicon atom is preferably contained, and a group containing a silicon atom is particularly preferably contained from the viewpoint of the affinity for silica.

[0148] The heteroatom-containing functional group can be introduced into the polymer chain ends of the conjugated diene rubber, for example, by reacting a heteroatom-containing compound with the active ends of the conjugated diene polymer chain having active ends via the above-described third step. Examples of the heteroatom-containing compound include compounds having a silicon atom, preferably alkoxysilane compounds or vinylsilane compounds, and more preferably alkoxysilane compounds having an amino group or vinylsilane compounds having an amino group.

[0149] Examples of the alkoxysilane compound having an amino group include [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [3-(dimethylamino)propyl]triethoxysilane, [3-(diethylamino)propyl]triethoxysilane, [3-(ethylmethylamino)propyl]trimethoxysilane, [3-(ethylmethylamino)propyl]triethoxysilane, [3-(dimethylamino)propyl]methyldimethoxysilane, [3-(diethylamino)propyl]methyldimethoxysilane, [3-(dimethylamino)propyl]ethyldimethoxysilane, [3-(diethylamino)propyl]ethyldimethoxysilane, [(3-methyl-3-ethylamino)propyl]methyldimethoxysilane, [(3-methyl-3-ethylamino)propyl]ethyldimethoxysilane, [3-(dimethylamino)propyl]methyldiethoxysilane, [3-(diethylamino)propyl]methyldiethoxysilane, [3-(dimethylamino)propyl]ethyldiethoxysilane, [3-(diethylamino)propyl]ethyldiethoxysilane, [3-(ethylmethylamino)propyl]methyldiethoxysilane, [3-(ethylmethylamino)propyl]ethyldiethoxysilane, [3-(benzylmethylamino)propyl]trimethoxysilane, [3-(benzylmethylamino)propyl]triethoxysilane, {3-[bis(methoxymethyl)amino]propyl}trimethoxysilane, {3-[bis(methoxyethyl)amino]propyl}trimethoxysilane, {3-[bis(methoxymethyl)amino]propyl}triethoxysilane, {3-[bis(methoxyethyl)amino]propyl}triethoxysilane, {3-[bis(ethoxyethyl)amino]propyl}trimethoxysilane, {3-[bis(ethoxymethyl)amino]propyl}trimethoxysilane, {3-[bis(ethoxyethyl)amino]propyl}triethoxysilane, {3-[bis(ethoxymethyl)amino]propyl}triethoxysilane, {3-[N,N-bis(trimethylsilyl)amino]propyl}trimethoxysilane, {3-[N,N-bis(trimethylsilyl)amino]propyl}triethoxysilane, {3-[N,N-bis(tert-butyldimethylsilyl)amino]propyl}trimethoxysilane, {3-[N,N-bis(tert-butyldimethylsilyl)amino]propyl}triethoxysilane, {3-[N,N-bis(trimethylsilyl)amino]propyl}methyldimethoxysilane, {3-[N,N-bis(trimethylsilyl)amino]propyl}methyldiethoxysilane, {3-[N,N-bis(tert-butyldimethylsilyl)amino]propyl}methyldimethoxysilane, {3-[N,N-bis(tert-butyldimethylsilyl)amino]propyl}methyldiethoxysilane, [3-(ethylmethylamino)propyl]trimethoxysilane, [3-(ethylmethylamino)propyl]triethoxysilane, [3-(ethylmethylamino)propyl]methyldimethoxysilane, [3-(ethylmethylamino)propyl]ethyldimethoxysilane, [3-(ethylmethylamino)propyl]methyldiethoxysilane, [3-(ethylmethylamino)propyl]ethyldiethoxysilane, etc.,

[0150] Among these, [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [3-(dimethylamino)propyl]triethoxysilane, and [3-(diethylamino)propyl]triethoxysilane are preferably used.

[0151] Examples of the vinylsilane compound having an amino group include bis(dimethylamino)methylvinylsilane, bis(diethylamino)methylvinylsilane, bis(n-propylamino)methylvinylsilane, bis(di(n-butyl)amino)methylvinylsilane, bis(dimethylamino)ethylvinylsilane, bis(diethylamino)ethylvinylsilane, bis(dipropylamino)ethylvinylsilane, bis(dibutylamino)ethylvinylsilane, etc.

[0152] In addition, as the compound having a silicon atom, a siloxane compound can also be preferably used. As the siloxane compound, any siloxane compound having a siloxane structure (-Si-O-) as the main chain can be used, and there is no particular limitation. An organosiloxane having an organic group in the side chain is preferred, and a polyorganosiloxane represented by the following general formula (4) is more preferred.

[0153] [Chemical formula 4]

[0154]

[0155] In the above general formula (4), R 3 ~R 10 is an alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms, and they may be the same or different from each other. X 9 and X 12 are any group selected from an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, and a group having 4 to 12 carbon atoms containing an epoxy group, and they may be the same or different from each other. X 10 is an alkoxy group having 1 to 5 carbon atoms or a group having 4 to 12 carbon atoms containing an epoxy group. When there are a plurality of X 10 , they may be the same or different from each other. X 11 is a group containing a repeating unit of 2 to 20 alkylene glycols. When X11 When there are multiple, they can be the same or different from each other. m is an integer from 1 to 200, n is an integer from 0 to 200, k is an integer from 0 to 200, and m + n + k is 1 or more.

[0156] In the polyorganosiloxane represented by the above general formula (4), as R that can form in the above general formula (4) 3 ~R 10 、X 9 and X 12 alkyl groups having 1 to 6 carbon atoms, examples thereof include: methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and cyclohexyl, etc. As aryl groups having 6 to 12 carbon atoms, examples thereof include phenyl and methylphenyl, etc. Among these, from the viewpoint of the ease of manufacturing the polyorganosiloxane itself, methyl and ethyl are preferred.

[0157] In addition, in the polyorganosiloxane represented by the above general formula (4), as alkoxy groups having 1 to 5 carbon atoms that can form X 9 、X 10 and X 12 examples thereof include methoxy, ethoxy, propoxy, isopropoxy, and butoxy, etc. Among these, from the viewpoint of the ease of manufacturing the polyorganosiloxane itself, methoxy and ethoxy are preferred.

[0158] Furthermore, in the polyorganosiloxane represented by the above general formula (4), as groups having 4 to 12 carbon atoms containing an epoxy group that can form X 9 、X 10 and X 12 groups represented by the following general formula (5) can be cited.

[0159] -Z 1 -Z 2 -E (5)

[0160] In the above general formula (5), Z 1 is an alkylene or alkylarylene group having 1 to 10 carbon atoms, Z 2 is a methylene group, a sulfur atom, or an oxygen atom, and E is a hydrocarbon group having 2 to 10 carbon atoms with an epoxy group.

[0161] As the group represented by the above general formula (5), a group in which Z 2 is an oxygen atom is preferred, and a group in which Z 2 is an oxygen atom and E is a glycidyl group is more preferred, and a group in which Z 1 is an alkylene group having 1 to 3 carbon atoms, Z 2 is an oxygen atom, and E is a glycidyl group is particularly preferred.

[0162] In addition, in the polyorganosiloxane represented by the above general formula (4), as X 9 and X 12 , in the above, a group having 4 to 12 carbon atoms containing an epoxy group or an alkyl group having 1 to 6 carbon atoms is particularly preferable. In addition, as X 10 , in the above, a group having 4 to 12 carbon atoms containing an epoxy group is particularly preferable. Further, it is more preferable that X 9 and X 12 are alkyl groups having 1 to 6 carbon atoms, and X 10 is a group having 4 to 12 carbon atoms containing an epoxy group.

[0163] In addition, in the polyorganosiloxane represented by the above general formula (4), as X 11 , that is, a group having a repeating unit of 2 to 20 alkylene glycols, a group represented by the following general formula (6) is preferable.

[0164] [Chemical formula 5]

[0165]

[0166] In the above general formula (6), t is an integer of 2 to 20, X 13 is an alkylene or alkarylene group having 2 to 10 carbon atoms, R 11 is a hydrogen atom or a methyl group, and X 14 is an alkoxy or aryloxy group having 1 to 10 carbon atoms. Among these, it is particularly preferable that t is an integer of 2 to 8, X 13 is an alkylene group having 3 carbon atoms, R 11 is a hydrogen atom, and X 14 is a methoxy group.

[0167] In the polyorganosiloxane represented by the above general formula (4), m is an integer of 1 to 200, preferably an integer of 20 to 150, and more preferably an integer of 30 to 120. When m is 1 to 200, the production of the polyorganosiloxane itself represented by the above general formula (4) becomes easier, and its viscosity does not become too high, and the operation also becomes easier.

[0168] In addition, in the polyorganosiloxane represented by the above general formula (4), n is an integer of 0 to 200, preferably an integer of 0 to 150, more preferably an integer of 0 to 120. k is an integer of 0 to 200, preferably an integer of 0 to 150, more preferably an integer of 0 to 130. The total of m, n, and k is 1 or more, preferably 3 to 400, more preferably 20 to 300, and particularly preferably 30 to 250. When the total of m, n, and k is 1 or more, the reaction of the polyorganosiloxane represented by the above general formula (4) with the conjugated diene polymer chain having an active end easily proceeds. Further, when the total of m, n, and k is 400 or less, the production of the polyorganosiloxane represented by the above general formula (4) itself becomes easy, its viscosity does not become too high, and the operation also becomes easy.

[0169] The method for reacting the conjugated diene polymer chain having an active end with the heteroatom-containing compound is not particularly limited, and examples thereof include a method of mixing them in a solvent capable of dissolving them respectively. As the solvent used at this time, solvents exemplified as the inactive solvents that can be used in the first step can be used. In addition, at this time, the method of adding the heteroatom-containing compound to the polymerization solution obtained through the third step is simple, and thus is preferred. Further, at this time, the heteroatom-containing compound may be dissolved in an inactive solvent and added to the polymerization system. The reaction temperature is not particularly limited, and is usually 0 to 120 °C. The reaction time is also not particularly limited, and is usually 1 minute to 1 hour.

[0170] When reacting the conjugated diene polymer chain having an active end with the heteroatom-containing compound, the amount of the heteroatom-containing compound used is preferably 0.1 to 100 moles, more preferably 0.3 to 50 moles, relative to 1 mole of the total amount of the polymerization initiator used for polymerization. When the amount of the heteroatom-containing compound used is within the above range, fuel economy can be further improved.

[0171] <Conjugated diene polymer composition>

[0172] The conjugated diene polymer composition of the present invention is a composition containing the above-described conjugated diene polymer of the present invention and a filler.

[0173] The conjugated diene polymer composition of the present invention may further contain other polymers in addition to the above-mentioned conjugated diene polymer of the present invention. As other polymers, for example, natural rubber (which may be modified natural rubbers such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), grafted natural rubber, etc.), polyisoprene rubber, emulsion-polymerized styrene-butadiene copolymer rubber, solution-polymerized styrene-butadiene copolymer rubber, polybutadiene rubber (which may be high-cis BR, low-cis BR. In addition, it may also be a polybutadiene rubber containing crystal fibers formed from 1,2-polybutadiene polymer), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber, butyl rubber (IIR), ethylene-propylene copolymer, chloroprene rubber, nitrile chloroprene rubber, and nitrile isoprene rubber, etc., other rubbers except the above-mentioned conjugated diene rubbers. Among these, natural rubber, polyisoprene rubber, polybutadiene rubber, and solution-polymerized styrene-butadiene copolymer rubber are preferred. Natural rubber is more preferred. These polymers can be used alone respectively, or two or more of them can be used in combination such as natural rubber and polybutadiene rubber, natural rubber and styrene-butadiene copolymer rubber, etc.

[0174] In the conjugated diene polymer composition of the present invention, the conjugated diene polymer of the present invention preferably accounts for 10 to 100% by weight of the polymer components in the conjugated diene polymer composition, and particularly preferably accounts for 50 to 100% by weight. By including the conjugated diene rubber of the present invention in the polymer components in such a proportion, the fuel economy can be made sufficiently excellent.

[0175] As fillers, for example, silica, calcium silicate, aluminum silicate, carbon black, calcium carbonate, talc, aluminum hydroxide, alumina, clay, and mica, etc. can be cited. Among these, from the aspect of being able to further improve the fuel economy, carbon black and silica are preferred, and silica is more preferred. These can be used alone respectively or two or more of them can be used in combination.

[0176] As silica, for example, dry-process silica, wet-process silica, colloidal silica, precipitated silica, calcium silicate, aluminum silicate, etc. can be cited. Among these, wet-process silica mainly composed of hydrous silicic acid is preferred. In addition, carbon-silica biphasic fillers in which silica is loaded on the surface of carbon black can also be used. These silicas can be used alone respectively or two or more of them can be used in combination. The nitrogen adsorption specific surface area of the silica used (measured by the BET method according to ASTM D3037-81) is preferably 20 to 400 m 2 / g, and more preferably 50 to 220 m 2 / g, particularly preferably 80 to 170 m 2 / g. In addition, the pH of the silica is preferably 5 to 10.

[0177] As the silica, various commercially available silicas can be used, for example. Examples include: "Hi-Sil 210", "Hi-Sil 233", "Hi-Sil 243LD" manufactured by PPG Industries, Inc.; "Zeosil 1115MP", "Zeosil 1165MP", "Zeosil 165GR" manufactured by Solvay; "ULTRAASIL VN2", "ULTRAASIL VN3" manufactured by Evonik; "NIPSIL VN3", "NIPSIL AQ", "NIPSIL ER", "NIPSIL RS-150" manufactured by Tosoh Silicone Co., Ltd., etc.

[0178] As the carbon black, examples include furnace black, acetylene black, thermal black, channel black, and graphite. As the channel black, examples include EPC, MPC, and CC. As the furnace black, examples include SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF. As the thermal black, examples include FT and MT. The carbon black can be used alone or in combination of two or more.

[0179] With respect to the polymer component in 100 parts by weight of the conjugated diene polymer composition, the compounding amount of the filler in the conjugated diene polymer composition of the present invention is preferably 10 to 250 parts by weight, more preferably 15 to 150 parts by weight, and further preferably 20 to 130 parts by weight. By making the compounding amount of the silica within the above range, the processability can be made sufficient, and the fuel economy can be further improved.

[0180] From the viewpoint of further improving fuel economy, a silane coupling agent can be further incorporated into the conjugated diene polymer composition of the present invention. The silane coupling agent is not particularly limited, and various silane coupling agents can be used. In the present invention, sulfide-based, mercapto-based, protected mercapto-based (e.g., silane coupling agent having a carbonylthio group), thiocyanate-based, vinyl-based, amino-based, methacrylate-based, glycidoxy-based, nitro-based, epoxy-based or chloro-based silane coupling agents can be preferably used. Specific examples of the silane coupling agent include: bis(3-(triethoxysilyl)propyl) disulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-(triethoxysilyl)propyl) tetrasulfide, γ-mercaptopropyltriethoxysilane, 3-[ethoxy bis(3,6,9,12,15-pentaoxaoctacosane-1-yloxy)silyl]-1-propanethiol, 3-octanoylthio-1-propyl-triethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, γ-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-trimethoxysilylpropylbenzothiazolyl tetrasulfide, 3-thiocyanatepropyltriethoxysilane, vinyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-trimethoxysilylpropyl methacrylate monosulfide, γ-glycidoxypropyltriethoxysilane, 3-nitropropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane and 3-chloropropyltrimethoxysilane, etc. In addition, NXT-Z100, NXT-Z30, NXT-Z45, NXT-Z60, NXT-Z45, NXT manufactured by Momentive Performance Materials Inc., Si69, Si75, VPSi363 manufactured by Evonik Corporation, etc. can also be used. These silane coupling agents can be used alone or in combination of two or more. In addition, one or two or more of these can be pre-oligomerized and used in an oligomerized state. The compounding amount of the silane coupling agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight, based on 100 parts by weight of the filler.

[0181] In addition, the conjugated diene polymer composition of the present invention preferably further contains a crosslinking agent. Examples of the crosslinking agent include: sulfur, sulfur-containing compounds such as sulfur halides, organic peroxides, quinone dioximes, organic polyamine compounds, alkylphenol resins having a hydroxymethyl group, etc. Among these, sulfur is preferably used. The compounding amount of the crosslinking agent is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight, based on 100 parts by weight of the polymer component in the conjugated diene polymer composition.

[0182] Furthermore, in the conjugated diene polymer composition of the present invention, in addition to the above components, compounding agents such as crosslinking accelerators, crosslinking activators, anti-aging agents, activators, processing oils, plasticizers, lubricants, tackifiers, etc. can be respectively compounded in required amounts according to conventional methods.

[0183] When sulfur or a sulfur-containing compound is used as a crosslinking agent, it is preferable to use a crosslinking accelerator and a crosslinking activator in combination. Examples of the crosslinking accelerator include: sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamate-based crosslinking accelerators; xanthate-based crosslinking accelerators, etc. Among these, a crosslinking accelerator containing a sulfenamide-based crosslinking accelerator is preferred. These crosslinking accelerators can be used alone or in combination of two or more. With respect to 100 parts by weight of the polymer component in the conjugated diene polymer composition, the compounding amount of the crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight.

[0184] Examples of the crosslinking activator include higher fatty acids such as stearic acid; zinc oxide, etc. These crosslinking activators can be used alone or in combination of two or more. With respect to 100 parts by weight of the polymer component in the conjugated diene polymer composition, the compounding amount of the crosslinking activator is preferably 0.05 to 20 parts by weight, and particularly preferably 0.5 to 15 parts by weight.

[0185] To obtain the conjugated diene polymer composition of the present invention, each component can be kneaded according to a conventional method. For example, after kneading components other than heat-unstable components such as crosslinking agents and crosslinking accelerators with the conjugated diene rubber, the crosslinking agent, crosslinking accelerator and other heat-unstable components can be mixed in the kneaded product to obtain the target composition. The kneading temperature of the components other than the heat-unstable components and the conjugated diene rubber is preferably 80 to 200 °C, more preferably 120 to 180 °C, and the kneading time is preferably 30 seconds to 30 minutes. In addition, the mixing of the kneaded product and the heat-unstable components is usually carried out after cooling to 100 °C or lower, preferably cooling to 80 °C or lower.

[0186] <Rubber crosslinked product>

[0187] The rubber crosslinked product of the present invention is obtained by crosslinking the above-mentioned conjugated diene polymer composition of the present invention.

[0188] The rubber crosslinked product of the present invention can be produced by the following method: using the conjugated diene polymer composition of the present invention, molding with a molding machine corresponding to a desired shape, such as an extruder, an injection molding machine, a compressor, a roll, etc., and heating to thereby carry out a crosslinking reaction, and fixing the shape as the rubber crosslinked product. In this case, crosslinking can be carried out after pre-molding, or crosslinking can be carried out simultaneously with molding. The molding temperature is usually 10 to 200°C, preferably 25 to 120°C. The crosslinking temperature is usually 100 to 200°C, preferably 130 to 190°C, and the crosslinking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, and particularly preferably 3 minutes to 6 hours.

[0189] In addition, depending on the shape, size, etc. of the rubber crosslinked product, sometimes even if the surface is crosslinked, the inside is not sufficiently crosslinked, so secondary crosslinking can also be carried out by further heating.

[0190] As the heating method, it is sufficient to appropriately select a usual method for rubber crosslinking such as press heating, steam heating, oven heating, hot air heating, etc.

[0191] Since the rubber crosslinked product of the present invention thus obtained is a rubber crosslinked product obtained by using the above-mentioned conjugated diene polymer of the present invention, it has excellent fuel economy. Therefore, the rubber crosslinked product of the present invention can effectively utilize its excellent fuel economy and be used for, for example: materials for various parts of a tire such as a tread, a base tread, a carcass, a sidewall, a bead portion, etc. in a tire; materials for hoses, belts, mats, shock-absorbing rubbers, and other various industrial products; an impact resistance improver for resins; a resin film buffer; soles; rubber shoes; golf balls; toys and other various uses. In particular, since the rubber crosslinked product of the present invention has excellent fuel economy, it is suitable for use as a material for tires.

[0192] Examples

[0193] Hereinafter, the present invention will be further described based on detailed examples, but the present invention is not limited to these examples. In addition, hereinafter, unless otherwise specified, "parts" are based on weight. Furthermore, the tests and evaluations are carried out in the following manner.

[0194] <1. Mooney viscosity (ML 1+4 )>

[0195] According to JIS K 6300 (1994), the Mooney viscosity of the conjugated diene polymer is measured at 100°C.

[0196] <2. Content of styrene units and amount of vinyl bonds>

[0197] According to JIS K6239 (2007), from 1The content (wt%) of styrene units and the vinyl bond amount (mol%) of conjugated diene units in the conjugated diene polymer are determined by the 1H-NMR method.

[0198] <3. Weight-average molecular weight (Mw)>

[0199] Under the following conditions (1) to (8), the weight-average molecular weight (Mw) of the entire conjugated diene polymer is measured by gel permeation chromatography (GPC).

[0200] (GPC apparatus and software)

[0201] (i) Liquid delivery pump: LC-20AD (manufactured by Shimadzu Corporation)

[0202] (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation)

[0203] (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation)

[0204] (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation)

[0205] (v) Differential refractive index detector (RID): RID-10A (manufactured by Shimadzu Corporation)

[0206] (vi) System controller: CBM-20A (manufactured by Shimadzu Corporation)

[0207] (vii) Measurement and analysis software: LC solution ver.1.24SP1

[0208] (viii) Measurement conditions

[0209] GPC column: Two Plus Pore series Poly Pore 7.5 mm I.D.×300 mm (manufactured by Agilent Technologies, Inc.)

[0210] Mobile phase: 25 mg of 2-(ethylamino)ethanol (manufactured by Fujifilm Wako Pure Chemical Corporation, special grade) is added to 3 L of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer)

[0211] Flow rate: 1 mL / min

[0212] Column oven temperature: 35°C

[0213] Detection: Differential refractive index detector (RID)

[0214] RID unit temperature: 35°C

[0215] Sample solution injection volume: 100 μL

[0216] Standard substance for GPC column calibration: PStQuick Kit-H (manufactured by Tosoh Corporation)

[0217] (ix) Sample solution preparation conditions

[0218] Solvent: Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer)

[0219] Sample solution concentration: 0.5 mg / mL

[0220] Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation)

[0221] Dissolution conditions: Add 10 mg of the sample and 20 mL of the solvent to a screw vial, stopper tightly, and stir at room temperature for 120 minutes at a stirring speed of 60 reciprocations / minute using DF-8020. Filter through a syringe equipped with a filter for filtration.

[0222] Filter for filtration: Millex-LG, pore size 0.2 μm, hydrophilic, PTFE, filter diameter 25 mm (manufactured by Merck KGaA)

[0223] <4. Low molecular weight P_ LOW , Medium molecular weight P_ MID , High molecular weight P_ HIGH 's molecular weight >

[0224] Based on the GPC chart of the conjugated diene polymer obtained by the above "3. Weight average molecular weight (Mw)", the molecular weight Mp_ of the low molecular weight P_ is determined by the above method LOW of LOW , Medium molecular weight P_ MID 's molecular weight Mp_ MID and High molecular weight P_ HIGH 's molecular weight Mp_ HIGH .

[0225] In addition, the conjugated diene polymers obtained in Synthesis Examples 1 to 5 and the conjugated diene polymers obtained by mixing used in Examples 4 to 6 all have a tri-modal distribution (i.e., have a GPC chart as shown in Figure 4 (A), Figure 4 (B)), so the molecular weights of the peaks at the peak tops of each peak are respectively taken as the molecular weight Mp_ of the low molecular weight P_ from the low molecular weight side LOW of LOW , Medium molecular weight P_ MID 's molecular weight Mp_ MID and High molecular weight P_ HIGH 's molecular weight Mp_ HIGH .

[0226] <5. Proportion of low molecular weight P_ LOW , medium molecular weight P_ MID , high molecular weight P_ HIGH >

[0227] Based on the GPC chart of the conjugated diene polymer obtained from the above-mentioned "3. Weight average molecular weight (Mw)", the proportion of low molecular weight P_ LOW was determined, the proportion of medium molecular weight P_ MID was determined, and the proportion of high molecular weight P_ HIGH was determined according to the above method.

[0228] In addition, the conjugated diene polymers obtained in Synthesis Examples 1 to 5 and the conjugated diene polymers obtained by mixing used in Examples 4 to 6 all had a three-peak distribution (i.e., they were Figure 4 (A), Figure 4 (as shown in the GPC chart of (B)). Therefore, the proportion of low molecular weight P_ LOW was calculated based on the area between Mp _1％_LOW and Figure 4 the Mp _谷_1 shown in (B), the proportion of medium molecular weight P_ MID was calculated based on the area between Figure 4 the Mp _谷_1 shown in (B) and Mp _谷_2 , and the proportion of high molecular weight P_ HIGH was calculated based on the area between Figure 4 the Mp _谷_2 shown in (B) and Mp _1％_HIGH .

[0229] <6. Contraction factor of medium molecular weight P_ MID , high molecular weight P_ HIGH >

[0230] The conjugated diene polymer was dissolved in tetrahydrofuran as a solvent at a concentration of 20 mg / 10 ml, and measurement was carried out using a GPC device (3D-GPC) (manufactured by Malvern Panalytical Ltd., trade name: "OMNISEC") equipped with a viscosity detector, a light scattering detector, and an RI detector. In the calibration of the light scattering detector (LS) and the viscosity detector (VISC) and the correction of the delay volume between the detectors, Polycal TDS-PS-N (weight average molecular weight Mw 104,349, polydispersity 1.04) from Malvern Panalytical Ltd. as a polystyrene standard substance was used at a solution concentration of 1 mg / ml. The refractive index increment (dn / dc) of the sample in tetrahydrofuran was 0.152 ml / g. The dn / dc of the polystyrene standard substance was 0.185 ml / g. When calculating the absolute molecular weight and the intrinsic viscosity ([η]; unit: dl / g) from the data of each detector, the data processing software OmniSEC (version 4.7) from Malvern Panalytical Ltd. was used, and the calculation was carried out with reference to the literature "Size Exclusion Chromatography, Springer (1999)". In addition, the refractive index increment refers to the rate of change of the refractive index with respect to the change in concentration. Moreover, from the intrinsic viscosity [η] obtained by the above measurement and the intrinsic viscosity [η]0 of the linear polymer obtained by calculation, the shrinkage factor g' = [η] / [η]0 at the molecular weight Mp_ MID of the medium molecular weight fraction P_ MID and the molecular weight Mp_ HIGH of the high molecular weight fraction P_ HIGH was calculated, and from this, the shrinkage factor g' of the medium molecular weight fraction P_ MID and the shrinkage factor g' of the high molecular weight fraction P_ HIGH were calculated. Here, the intrinsic viscosity [η]0 of the linear polymer was calculated and used by the following formula.

[0231] [η]0 = 10 -3.883 ×M 0.771 (dl / g)

[0232] Here, M is the absolute molecular weight.

[0233] <Measurement conditions>

[0234] Measurement device: OMNISEC manufactured by Malvern Panalytical Ltd.

[0235] Detectors: Light scattering detector, RI detector, UV detector, viscosity detector

[0236] GPC columns: TSKgel G4000HXL, TSKgel G5000HXL, TSKgel G6000HXL manufactured by Tosoh Corporation

[0237] Concentration of sample solution: 20 mg / 10 ml

[0238] Solvent: Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer)

[0239] Injection volume: 100 μl

[0240] Measurement temperature: 40 °C

[0241] Dissolution conditions: Stir at room temperature for 2 hours

[0242] Mobile phase: Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer) containing 0.3 vol% of 2-ethylaminoethanol

[0243] Flow rate of mobile phase: 1 ml / minute

[0244] <7. Medium molecular weight body P_ MID , High molecular weight body P_ HIGH Adsorption rate to silica >

[0245] Based on the GPC chart of the conjugated diene polymer obtained by the above "3. Weight average molecular weight (Mw)", the molecular weight range showing the medium molecular weight body P_ MID and the molecular weight range showing the high molecular weight body P_ HIGH are determined. Medium molecular weight body P_ MID , High molecular weight body P_ HIGH The adsorption rate to silica is calculated from the results of GPC measurement using a styrene-based column measured under the following conditions and the results of GPC measurement using a silica-based column measured under the following conditions. The conditions for GPC measurement using a styrene-based column are as follows.

[0246] (GPC apparatus and software)

[0247] (i) Liquid delivery pump: LC-20AD (manufactured by Shimadzu Corporation)

[0248] (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation)

[0249] (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation)

[0250] (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation)

[0251] (v) Differential refractive index detector (RID): RID-10A (manufactured by Shimadzu Corporation)

[0252] (vi) System Controller: CBM-20A (manufactured by Shimadzu Corporation)

[0253] (vii) Measurement and Analysis Software: LC solution ver.1.24SP1

[0254] (viii) Measurement Conditions

[0255] GPC Column: Two PlusPore series PolyPore 7.5mm I.D.×300mm (manufactured by Agilent Technologies, Inc.)

[0256] Mobile Phase: Add 25 mg of 2-(ethylamino)ethanol (manufactured by Fujifilm Wako Pure Chemical Corporation, special grade) to 3 L of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer).

[0257] Flow Rate: 1 mL / min

[0258] Column Oven Temperature: 35°C

[0259] Detection: Differential Refractometer Detector (RID)

[0260] RID Unit Temperature: 35°C

[0261] Sample Solution Injection Volume: 100 μL

[0262] Standard Substance for GPC Column Calibration: PSt Quick Kit-H (manufactured by Tosoh Corporation)

[0263] (ix) Sample Solution Preparation Conditions

[0264] Solvent: Add 5 mg of standard polystyrene A5000 with a molecular weight of 5000 (manufactured by Tosoh Corporation) as an internal standard to 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer).

[0265] Sample Solution Concentration: 0.5 mg / mL

[0266] Automatic Oscillator for Dissolution: DF-8020 (manufactured by Tosoh Corporation)

[0267] Dissolution Conditions: Add 10 mg of the sample and 20 mL of the solvent to a screw vial, seal it tightly, and stir at room temperature for 120 minutes with a stirring speed of 60 reciprocations / min using DF-8020. Filter through a syringe equipped with a filter for filtration.

[0268] Filter for Filtration: Millex-LG, pore size 0.2 μm, hydrophilic, PTFE, filter diameter 25 mm (manufactured by Merck KGaA)

[0269] The conditions for GPC measurement using a silica-based column are as follows.

[0270] (GPC apparatus and software)

[0271] (i) Liquid delivery pump: LC-20AD (manufactured by Shimadzu Corporation)

[0272] (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation)

[0273] (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation)

[0274] (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation)

[0275] (v) Differential refractive index detector (RID): RID-10A (manufactured by Shimadzu Corporation)

[0276] (vi) System controller: CBM-20A (manufactured by Shimadzu Corporation)

[0277] (vii) Measurement and analysis software: LC solution ver.1.24SP1

[0278] (viii) Measurement conditions

[0279] GPC columns: 1 Zorbax PSM1000-S (6.2×250 mm, manufactured by Agilent Technologies), 1 Zorbax PSM-300 (6.2×250 mm, manufactured by Agilent Technologies), 1 Zorbax PSM60-S (6.2×250 mm, manufactured by Agilent Technologies)

[0280] Mobile phase: Tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer)

[0281] Flow rate: 0.7 mL / min

[0282] Column oven temperature: 35 °C

[0283] Detection: Differential refractive index detector (RID)

[0284] RID cell temperature: 35 °C

[0285] Sample solution injection volume: 100 μL

[0286] Standard substance for GPC column calibration: PSt Quick Kit-H (manufactured by Tosoh Corporation)

[0287] (ix) Sample solution preparation conditions

[0288] Solvent: To 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Inc., special grade, without stabilizer), 5 mg of standard polystyrene A5000 with a molecular weight of 5000 (manufactured by Tosoh Corporation) as an internal standard was added.

[0289] Sample solution concentration: 0.5 mg / mL

[0290] Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation)

[0291] Dissolution conditions: 10 mg of the sample and 20 mL of the solvent were added to a screw vial and sealed tightly, and stirred at room temperature for 120 minutes with a stirring speed of 60 reciprocations / minute using DF-8020. Filtration was performed through a syringe equipped with a filter for filtration.

[0292] Filter for filtration: Millex-LG, pore size 0.2 μm, hydrophilic, PTFE, filter diameter 25 mm (manufactured by Merck & Co., Inc.)

[0293] Then, based on the obtained measurement results, the medium molecular weight fraction P_ MID The adsorption rate to silica was calculated by the following formula (2), and the high molecular weight fraction P_ HIGH The adsorption rate to silica was calculated by the following formula (3).

[0294] Medium molecular weight fraction P_ MID Adsorption rate to silica (%) = {1 - (b1 × c1) / (a1 × d1)} × 100 (2)

[0295] a1: Area (%) of the medium molecular weight fraction P_ MID measured by GPC using a styrene-based column

[0296] b1: Area (%) of the internal standard polystyrene using a styrene-based column

[0297] c1: Area (%) of the medium molecular weight fraction P_ MID measured by GPC using a silica-based column

[0298] d1: Area (%) of the internal standard polystyrene using a silica-based column

[0299] High molecular weight fraction P_ HIGH Adsorption rate to silica (%) = {1 - (b2 × c2) / (a2 × d2)} × 100 (3)

[0300] a2: Area (%) of the high molecular weight fraction P_ HIGH measured by GPC using a styrene-based column

[0301] b2: Area (%) of internal standard polystyrene using a styrene-based column

[0302] c2: High molecular weight body P_ determined by GPC using a silica-based column HIGH Area (%)

[0303] d2: Area (%) of internal standard polystyrene using a silica-based column

[0304] In addition, the conjugated diene polymers obtained in Synthesis Examples 1 to 5 and the conjugated diene polymers obtained by mixing used in Examples 4 to 6 all have a tri-modal distribution (i.e., have a GPC chart as shown in Figure 4 (A), Figure 4 (B)). Therefore, the area between Mp Figure 4 shown in (B) and Mp _谷_1 is taken as the area of the medium molecular weight body P_ _谷_2 MID , and the area between Mpshown in (B) and Mp Figure 4 (B) and Mp _谷_2 and Mp _1％_HIGH is taken as the area of the high molecular weight body P_ HIGH .

[0305] <8. Mooney viscosity of the mixture (ML 1+4 )>

[0306] The Mooney viscosity (mixture Mooney viscosity) of the conjugated diene polymer composition is measured at 100 °C in accordance with JIS K6300 (1994).

[0307] <9. Fuel economy>

[0308] Test pieces with a width of 1 mm or 2 mm and a length of 40 mm are punched out from the rubber crosslinked sheet for testing. The loss tangent (tanδ(30 °C)) of the test piece at a temperature of 30 °C is measured under the conditions of a frequency of 10 Hz, an initial elongation of 10%, and a strain amplitude of 0.25% by a viscoelasticity measuring device (manufactured by Ueshima Seisakusho Co., Ltd.).

[0309] [Synthesis Example 1]

[0310] The stainless-steel polymerization reactor with a content volume of 30 L and a stirring device is cleaned and dried, and the internal environment of the polymerization reactor is replaced with dry nitrogen. Then, 12.24 kg of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (ordinary product), density 0.68 g / ml), 3.51 kg of cyclohexane, 608 g of 1,3-butadiene, 743 g of styrene, 9.12 mL of tetrahydrofuran, 0.75 mL of ethylene glycol diethyl ether, and 2.24 mL of ethylene glycol dibutyl ether are put into the polymerization reactor. Then, in order to detoxify in advance the impurities that play a role in the inactivation of the polymerization initiator, a small amount of a hexane solution of n-butyllithium (n-BuLi) as a scavenger is put into the polymerization reactor, and then a n-hexane solution containing 12.17 mol of n-BuLi is put into the polymerization reactor to initiate the polymerization reaction. During the polymerization reaction, the temperature in the polymerization reactor is adjusted to 65 °C, and the solution in the polymerization reactor is stirred at a stirring speed of 130 rpm. After 20 minutes of polymerization initiation, 1,3-butadiene and styrene are continuously supplied into the polymerization reactor.

[0311] After 80 minutes of polymerization reaction, a n-hexane solution containing 1.17 mmol of silicon tetrachloride (SiCl4) is put into the polymerization reactor and the polymerization reaction is carried out for 10 minutes. Then, a n-hexane solution containing 5.76 mmol of bis(diethylamino)methylvinylsilane and 2.52 mmol of n-BuLi is put into the polymerization reactor and the polymerization reaction is carried out for 160 minutes. In addition, during the total polymerization period of 4 hours and 40 minutes, 1,3-butadiene is continuously supplied into the polymerization reactor over 200 minutes, and styrene is continuously supplied into the polymerization reactor over 115 minutes. The total supply amount of 1,3-butadiene is 1039 g, and the total supply amount of styrene is 310 g.

[0312] While maintaining the temperature in the polymerization reactor at 65 °C, the polymerization solution in the polymerization reactor is stirred at a stirring speed of 130 rpm, and 15.01 mmol of [3-(diethylamino)propyl]trimethoxysilane as a modifier is added to the polymerization solution and stirred for 15 minutes. Then, a n-hexane solution containing 30.00 mmol of n-BuLi is added to the polymerization solution and stirred for 15 minutes. Then, 20 mL of a n-hexane solution containing 2.8 mL of methanol is put into the polymerization reactor, and the polymerization solution is stirred for 5 minutes.

[0313] The stirrer in the polymerization reactor is extracted, and a part of the stirrer is dried at room temperature for 24 hours to evaporate most of the volatile components, and then dried under reduced pressure at 55 °C for 12 hours to obtain a polymer sample for measurement, and the amount of vinyl bonds, the content of styrene units, the molecular weight (weight-average molecular weight (Mw), and low molecular weight body P_LOW , medium molecular weight polymer P_ MID and high molecular weight polymer P_ HIGH in terms of molecular weight), medium molecular weight polymer P_ MID and high molecular weight polymer P_ HIGH in terms of shrinkage factor, and medium molecular weight polymer P_ MID and high molecular weight polymer P_ HIGH in terms of the adsorption rate for silica. The results are shown in Table 1.

[0314] The stirrer in the polymerization reactor was extracted, and 10.8 g of 4,6-bis(octylthiomethyl)-o-cresol (manufactured by BASF Corporation, trade name: Irganox 1520L, manufactured by BASF Corporation) and 675 g of filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to the stirrer to obtain a mixture. Then, most of the volatile components in the obtained mixture were evaporated at room temperature for 24 hours, and further dried under reduced pressure at 55 °C for 12 hours to obtain a conjugated diene-based polymer (A1).

[0315] [Synthesis Example 2]

[0316] A stainless steel polymerization reactor with a stirring device having an internal volume of 30 L was cleaned and dried, and the environment inside the polymerization reactor was replaced with dry nitrogen. Then, 12.24 kg of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (ordinary product), density 0.68 g / ml), 3.51 kg of cyclohexane, 608 g of 1,3-butadiene, 743 g of styrene, 9.12 mL of tetrahydrofuran, 0.75 mL of ethylene glycol diethyl ether, and 2.24 mL of ethylene glycol dibutyl ether were charged into the polymerization reactor. Then, in order to previously detoxify the impurities that play a role in the inactivation of the polymerization initiator, a small amount of a hexane solution of n-butyllithium (n-BuLi) as a scavenger was charged into the polymerization reactor, and then a n-hexane solution containing 10.27 mmol of n-BuLi was charged into the polymerization reactor to initiate a polymerization reaction. During the polymerization reaction, the temperature inside the polymerization reactor was adjusted to 65 °C, and the solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm. After 20 minutes of polymerization initiation, 1,3-butadiene and styrene were continuously supplied into the polymerization reactor.

[0317] After 80 minutes of polymerization reaction, a n-hexane solution containing 0.65 mmol of 1,6-bis(trichlorosilyl)hexane was introduced into the polymerization reactor and the polymerization reaction was carried out for 10 minutes. Then, a n-hexane solution containing 5.76 mmol of bis(diethylamino)methylvinylsilane and 5.77 mmol of n-BuLi was introduced into the polymerization reactor, and the polymerization reaction was carried out for 160 minutes. In addition, during the total polymerization period of 4 hours and 40 minutes, 1,3-butadiene was continuously supplied to the polymerization reactor over 200 minutes, and styrene was continuously supplied to the polymerization reactor over 115 minutes. The total supply amount of 1,3-butadiene was 1039 g, and the total supply amount of styrene was 310 g.

[0318] While maintaining the temperature in the polymerization reactor at 65 °C, the polymerization solution in the polymerization reactor was stirred at a stirring speed of 130 rpm, and 18.21 mmol of [3-(diethylamino)propyl]trimethoxysilane as a modifier was added to the polymerization solution and stirred for 15 minutes. Then, a n-hexane solution containing 36.40 mmol of n-BuLi was added to the polymerization solution and stirred for 15 minutes. Then, 20 mL of a hexane solution containing 3.2 mL of methanol was introduced into the polymerization reactor, and the polymerization solution was stirred for 5 minutes.

[0319] The stirrer in the polymerization reactor was extracted, and a part of the stirrer was dried at room temperature for 24 hours to evaporate most of the volatile components, and then dried under reduced pressure at 55 °C for 12 hours to obtain a polymer sample for measurement, and the same measurement as in Synthesis Example 1 was carried out. The results are shown in Table 1.

[0320] The stirrer in the polymerization reactor was extracted, 10.8 g of 4,6-bis(octylthiomethyl)-o-cresol (manufactured by BASF Corporation, trade name: Irganox 520L, manufactured by BASF Corporation) and 675 g of a filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to the stirrer to obtain a mixture. Moreover, most of the volatile components in the obtained mixture were evaporated at room temperature for 24 hours, and then dried under reduced pressure at 55 °C for 12 hours to obtain a conjugated diene polymer (A2).

[0321] [Synthesis Example 3]

[0322] The stainless steel polymerization reactor with a stirring device and an internal volume of 20 L was cleaned and dried, and the internal environment of the polymerization reactor was replaced with dry nitrogen. Subsequently, 8.16 kg of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (ordinary grade), density 0.68 g / ml), 2.34 kg of cyclohexane, 405 g of 1,3-butadiene, 495 g of styrene, 6.08 mL of tetrahydrofuran, 0.50 mL of ethylene glycol diethyl ether, and 1.50 mL of ethylene glycol dibutyl ether were charged into the polymerization reactor. Next, in order to detoxify in advance the impurities that play a role in the inactivation of the polymerization initiator, a small amount of hexane solution of n-butyllithium (n-BuLi) as a scavenger was charged into the polymerization reactor, and then a hexane solution containing 6.86 mmol of n-BuLi was charged into the polymerization reactor to initiate the polymerization reaction. During the polymerization reaction, the temperature inside the polymerization reactor was adjusted to 65 °C, and the solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm. After 20 minutes of polymerization initiation, 1,3-butadiene and styrene were continuously supplied into the polymerization reactor.

[0323] After 80 minutes of polymerization reaction, a hexane solution containing 0.043 mmol of 1,6-bis(trichlorosilyl)hexane was charged into the polymerization reactor and the polymerization reaction was carried out for 10 minutes. Next, a hexane solution containing 3.84 mmol of bis(diethylamino)methylvinylsilane and 3.84 mmol of n-BuLi was charged into the polymerization reactor and the polymerization reaction was carried out for 160 minutes. In addition, during the total polymerization period of 4 hours and 50 minutes, 1,3-butadiene was continuously supplied into the polymerization reactor over 200 minutes, and styrene was continuously supplied into the polymerization reactor over 115 minutes. The total supply amount of 1,3-butadiene was 693 g, and the total supply amount of styrene was 207 g.

[0324] While maintaining the temperature inside the polymerization reactor at 65 °C, the polymerization solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm, 3.24 mmol of 2-butanol was added to the polymerization solution, and it was stirred for 15 minutes. Next, 7.29 mmol of [3-(diethylamino)propyl]trimethoxysilane as a modifier was added to the polymerization solution. After stirring for 15 minutes, a hexane solution containing 14.6 mmol of n-BuLi was added to the polymerization solution and it was stirred for 15 minutes. Next, 20 mL of a hexane solution containing 1.6 mL of methanol was charged into the polymerization reactor, and the polymerization solution was stirred for 5 minutes.

[0325] The stirrer in the polymerization reactor was extracted. A portion of the stirrer was dried at room temperature for 24 hours to evaporate most of the volatile components, and then vacuum dried at 55 °C for 12 hours to obtain a polymer sample for measurement. The same measurements as in Synthesis Example 1 were carried out. The results are shown in Table 1.

[0326] The stirrer in the polymerization reactor was extracted. 7.2 g of 4,6-bis(octylthiomethyl)-o-cresol (manufactured by BASF Corporation, trade name: Irganox 520L, manufactured by BASF Corporation) and 450 g of filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to the stirrer to obtain a mixture. Moreover, most of the volatile components in the obtained mixture were evaporated at room temperature for 24 hours, and then vacuum dried at 55 °C for 12 hours to obtain a conjugated diene polymer (A3).

[0327] [Synthesis Example 4]

[0328] A stainless steel polymerization reactor with a stirring device and an internal volume of 20 L was cleaned and dried, and the internal environment of the polymerization reactor was replaced with dry nitrogen. Next, 8.16 kg of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (ordinary product), density 0.68 g / ml), 2.34 kg of cyclohexane, 405 g of 1,3-butadiene, 495 g of styrene, 6.08 mL of tetrahydrofuran, 0.50 mL of ethylene glycol diethyl ether, and 1.50 mL of ethylene glycol dibutyl ether were charged into the polymerization reactor. Next, in order to detoxify in advance the impurities that play a role in the inactivation of the polymerization initiator, a small amount of a hexane solution of n-butyllithium (n-BuLi) as a scavenger was charged into the polymerization reactor, and then a n-hexane solution containing 1.25 mmol of n-BuLi was charged into the polymerization reactor to initiate a polymerization reaction. During the polymerization reaction, the temperature inside the polymerization reactor was adjusted to 65 °C, and the solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm. After 20 minutes of polymerization initiation, 1,3-butadiene and styrene were continuously supplied into the polymerization reactor.

[0329] After 40 minutes of the polymerization reaction, a hexane solution containing 3.75 mmol of n-BuLi was introduced into the polymerization reactor and the polymerization reaction was carried out for 35 minutes. Then, 3.84 mmol of bis(diethylamino)methylvinylsilane was introduced into the polymerization reactor. After 35 minutes of the polymerization reaction, a hexane solution containing 5.00 mmol of n-BuLi was introduced into the polymerization reactor and the polymerization reaction was carried out for 140 minutes. In addition, during the total polymerization period of 4 hours and 40 minutes, 1,3-butadiene was continuously supplied to the polymerization reactor over 200 minutes, and styrene was continuously supplied to the polymerization reactor over 115 minutes. The total supply amount of 1,3-butadiene was 693 g, and the total supply amount of styrene was 207 g.

[0330] While maintaining the temperature in the polymerization reactor at 65 °C, the polymerization solution in the polymerization reactor was stirred at a stirring speed of 130 rpm, and 15.0 mmol of [3-(diethylamino)propyl]trimethoxysilane as a modifier was added to the polymerization solution and stirred for 15 minutes. Then, a hexane solution containing 26.25 mmol of n-BuLi was added to the polymerization solution and stirred for 15 minutes. Then, 20 mL of a hexane solution containing 2.23 mL of methanol was introduced into the polymerization reactor, and the polymerization solution was stirred for 5 minutes.

[0331] The stirrer in the polymerization reactor was extracted, and a part of the stirrer was dried at room temperature for 24 hours to evaporate most of the volatile components, and then dried under reduced pressure at 55 °C for 12 hours to obtain a polymer sample for measurement, and the same measurement as in Synthesis Example 1 was carried out. The results are shown in Table 1.

[0332] The stirrer in the polymerization reactor was extracted, 7.2 g of 4,6-bis(octylthiomethyl)-o-cresol (manufactured by BASF, trade name: Irganox 520L, manufactured by BASF) and 450 g of a filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to the stirrer to obtain a mixture. Moreover, most of the volatile components in the obtained mixture were evaporated at room temperature for 24 hours, and then dried under reduced pressure at 55 °C for 12 hours to obtain a conjugated diene polymer (B1).

[0333] [Synthesis Example 5]

[0334] The stainless-steel polymerization reactor with a stirring device and an internal volume of 20 L was cleaned and dried, and the internal environment of the polymerization reactor was replaced with dry nitrogen. Subsequently, 8.16 kg of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (ordinary grade), density 0.68 g / ml), 2.34 kg of cyclohexane, 405 g of 1,3-butadiene, 495 g of styrene, 6.08 mL of tetrahydrofuran, 0.50 mL of ethylene glycol diethyl ether, and 1.50 mL of ethylene glycol dibutyl ether were charged into the polymerization reactor. Subsequently, in order to detoxify in advance the impurities that play a role in the inactivation of the polymerization initiator, a small amount of a hexane solution of n-butyllithium (n-BuLi) as a scavenger was charged into the polymerization reactor, and a n-hexane solution containing 1.25 mmol of n-BuLi was charged into the polymerization reactor to initiate the polymerization reaction. During the polymerization reaction, the temperature inside the polymerization reactor was adjusted to 65 °C, and the solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm. Twenty minutes after the polymerization was initiated, 1,3-butadiene and styrene were continuously supplied into the polymerization reactor.

[0335] Forty minutes after the polymerization reaction was carried out, a n-hexane solution containing 3.75 mmol of n-BuLi was charged into the polymerization reactor and the polymerization reaction was carried out for 35 minutes. Subsequently, 3.84 mmol of bis(diethylamino)methylvinylsilane was charged into the polymerization reactor. After the polymerization reaction was carried out for 35 minutes, a n-hexane solution containing 5.00 mmol of n-BuLi was charged into the polymerization reactor, and the polymerization reaction was carried out for 140 minutes. In addition, during the total polymerization period of 4 hours and 40 minutes, 1,3-butadiene was continuously supplied into the polymerization reactor over 200 minutes, and styrene was continuously supplied into the polymerization reactor over 115 minutes. The total supply amount of 1,3-butadiene was 693 g, and the total supply amount of styrene was 207 g.

[0336] While maintaining the temperature inside the polymerization reactor at 65 °C, the polymerization solution inside the polymerization reactor was stirred at a stirring speed of 130 rpm, and 20.0 mmol of [3-(diethylamino)propyl]trimethoxysilane as a modifier was added to the polymerization solution and stirred for 15 minutes. Subsequently, a n-hexane solution containing 26.25 mmol of n-BuLi was added to the polymerization solution and stirred for 15 minutes. Subsequently, 20 mL of a n-hexane solution containing 2.77 mL of methanol was charged into the polymerization reactor, and the polymerization solution was stirred for 5 minutes.

[0337] The stirrer inside the polymerization reactor was extracted, and a part of the stirrer was dried at room temperature for 24 hours to evaporate most of the volatile components, and then dried under reduced pressure at 55 °C for 12 hours to obtain a polymer sample for measurement, and the same measurement as in Synthesis Example 1 was carried out. The results are shown in Table 1.

[0338] The stirred material in the polymerization reactor was extracted and divided into two portions in the same weight. To one portion of the stirred material, 3.6 g of 4,6-bis(octylthiomethyl)-o-cresol (manufactured by BASF, trade name: Irganox 520L, manufactured by BASF) and 225 g of a filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to obtain a mixture. Then, most of the volatile components in the obtained mixture were evaporated at room temperature for 24 hours, and further dried under reduced pressure at 55 °C for 12 hours to obtain a conjugated diene polymer (B2).

[0339] [Synthesis Example 6]

[0340] To the remaining stirred material that was divided into two portions in the above Synthesis Example 5, 3.6 g of "Irganox 520L (Irganox 1520L: 4,6-bis(octylthiomethyl)-o-cresol, manufactured by BASF)", 1.8 g of "Sumilizer GM (acrylate-2-tert-butyl-4-methyl-6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl ester, manufactured by Sumitomo Chemical Co., Ltd.)", 0.9 g of "Sumilizer TP-D (bis[3-(dodecylthio)propionic acid] 2,2-bis[[3-(dodecylthio)-1-oxopropoxy]methyl]-1,3-propanediol ester, manufactured by Sumitomo Chemical Co., Ltd.)" and 225 g of a filling oil (manufactured by Nippon Energy Corporation, trade name: JOMO PROCESS NC-140) were added to obtain a mixture. Most of the volatile components in the mixture were evaporated at room temperature for 24 hours, and further dried under reduced pressure at 55 °C for 12 hours to obtain a conjugated diene polymer (B3).

[0341] Table 1 shows the properties, etc. of the conjugated diene polymers obtained in Synthesis Examples 1 to 6.

[0342] [Table 1]

[0343] Table 1

[0344] Synthesis Example 1 Synthesis Example 2 Synthesis Example 3 Synthesis Example 4 Synthesis Example 5 Synthesis Example 6 Types of polymers (A1) (A2) (A3) (B1) (B2) (B3) Content of styrene units (wt%) 39 39 39 39 39 39 Amount of vinyl bonds (mol%) 38 37 38 38 37 37 <![CDATA[Mooney viscosity (ML 1+4 )]]> 45 38 35 48 51 51 <![CDATA[Weight-average molecular weight Mw (×10 4 )]]> 48.2 48.9 47.3 39 55.6 55.6 Molecular weight distribution pattern Trimodality Trimodality Trimodality Trimodality Trimodality Trimodality <![CDATA[High molecular weight polymer P_ HIGH with a molecular weight Mp_ HIGH (×10 4 )]]> 76.1 120.4 107.2 75.8 100.7 100.7 <![CDATA[Content ratio (wt%) of high molecular weight substance P_ HIGH > 40 28 23 35 49 49 <![CDATA[Medium molecular weight body P_MID with a molecular weight Mp_ MID (×10 4 )]]> 38.8 42.9 36.9 34.4 34.2 34.2 <![CDATA[Content ratio (wt%) of medium molecular weight body P_ MID > 50 56 62 53 39 39 <![CDATA[Low molecular weight substance P_LOW has a molecular weight Mp_ LOW (×10 4 )]]> 14.5 12.5 10.6 7.2 1.52 15.2 <![CDATA[Content ratio (wt%) of low molecular weight body P_ LOW > 10 16 15 12 12 12 <![CDATA[High molecular weight polymer P_ HIGH shrinkage factor]]> 0.73 0.47 0.44 0.83 0.93 0.93 <![CDATA[Medium molecular weight body P_ MID contraction factor]]> 0.91 0.86 0.86 0.87 0.87 0.87 <![CDATA[High molecular weight polymer P_ HIGH Adsorption rate (%) for silica]]> 40.0 20.4 11.4 80.0 90.9 90.9 <![CDATA[Medium molecular weight body P_ MID Adsorption rate to silica (%)]]> 78.7 73.2 46.5 71.2 87.0 87.0

[0345] <Preparation of Conjugated Diene Polymer Composition and Fabrication of Rubber Crosslinked Sheet>

[0346] The materials other than sulfur and vulcanization accelerators were kneaded at 150 °C for 5 minutes using a LABO PLAST mill at the compounding ratios (parts by weight) shown in Table 2 to prepare the conjugated diene polymer compositions of Examples 1 to 6 and Comparative Examples 1 to 3. Then, using the obtained conjugated diene polymer compositions, the Mooney viscosity of the mixtures was measured according to the above method. The results are shown in Table 2. In addition, in Examples 4 to 6, two conjugated diene polymers were mixed, but a mixture of two conjugated diene polymers was separately prepared, and the shrinkage factors of the medium molecular weight fraction P_ MID and the high molecular weight fraction P_ HIGH , and the adsorption rates of the medium molecular weight fraction P_ MID and the high molecular weight fraction P_ HIGH to silica were measured.

[0347] Next, sulfur and a vulcanization accelerator were added to the obtained conjugated diene polymer compositions, and sheets were formed using a 6-inch roll at 50 °C, and the sheets were heated at 160 °C for 35 to 40 minutes to crosslink them, thereby producing the rubber crosslinked sheets of Examples 1 to 6 and Comparative Examples 1 to 3. The results are shown in Table 2.

[0348] [Table 2]

[0349]

[0350] In addition, the respective materials shown in Table 2 are as follows.

[0351] · Silica: manufactured by Evonik, trade name “Ultrasil VN3-GR”

[0352] · Oil: manufactured by JXT Energy, trade name “JOMO PROCESS NC-140”

[0353] · Silane coupling agent: bis(3-(triethoxysilyl)propyl)tetrasulfide (manufactured by Degussa, trade name “Si69”)

[0354] · Carbon black: manufactured by Cabot Japan, trade name “N339”

[0355] · Zinc oxide: manufactured by Shoindo Chemical Industry Co., Ltd., trade name “Zinc Oxide 2 Types”

[0356] · Antioxidant: 6PPD, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., trade name “Nocrac 6C”)

[0357] · Stearic acid: trade name “Pearl Stearic Acid Tsubaki” manufactured by NOF Corporation

[0358] · Wax: manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Sunnoc N"

[0359] · Processing aid: manufactured by Struktol, trade name "Struktol EF44"

[0360] · Vulcanization accelerator (1): manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Nocceler CZ-G" of N-cyclohexyl-2-benzothiazolesulfonamide

[0361] · Vulcanization accelerator (2): diphenylguanidine (manufactured by Ouchi Shinsei Chemical Industry Co., Ltd., trade name "Nocceler D")

[0362] · Sulfur: manufactured by Tsurumi Chemical Co., Ltd., trade name "Sulfur 325 mesh"

[0363] Table 2 shows the results of the Mooney viscosity (A) and fuel economy (B) of the mixtures in each example and comparative example. The smaller the value of the Mooney viscosity (A) of the mixture, the better the processability. The smaller the value of the fuel economy (B), the more fuel-efficient.

[0364] Moreover, as shown in Table 2, the shrinkage factor of the high molecular weight polymer P_ HIGH is 0.4 to 0.8, the adsorption rate of the high molecular weight polymer P_ HIGH to silica is 75% or less, and the adsorption rate of the medium molecular weight polymer P_ MID to silica is 40 to 100%. When a conjugated diene-based polymer is compounded with silica as a filler to form a conjugated diene-based polymer composition, the value obtained by multiplying the Mooney viscosity (A) of the mixture by the fuel economy (B) when forming a rubber crosslink ( (A)×(B)) is low, and the balance between processability and fuel economy is excellent (Examples 1 to 6).

[0365] On the other hand, for a conjugated diene-based polymer in which the shrinkage factor of the high molecular weight polymer P_ HIGH is greater than 0.8 and the adsorption rate of the high molecular weight polymer P_ HIGH to silica is greater than 75%, the value obtained by multiplying the Mooney viscosity (A) of the mixture by the fuel economy (B) ((A)×(B)) is high, and the processability and fuel economy are poor (Comparative Examples 1 to 3).

[0366] In addition, in Table 2, the value obtained by multiplying the Mooney viscosity (A) of the mixture by the fuel economy (B) is shown as an index (the larger the index, the better) with the result of Comparative Example 1 as 100.

Claims

1. A conjugated diene polymer containing at least conjugated diene monomer units, The shrinkage factor of the high molecular weight fraction of the conjugated diene polymer is 0.4 to 0.8, The adsorption rate of the high molecular weight fraction of the conjugated diene polymer to silica is 75% or less, The adsorption rate of the medium molecular weight fraction of the conjugated diene polymer to silica is 40 to 100%, The shrinkage factor of the high molecular weight fraction is measured as follows: The conjugate diene polymer is measured using a GPC device equipped with a viscosity detector, a light scattering detector, and a differential refractive index detector, and the molecular weight Mp_ of the high molecular weight component is determined from the measurement results. HIGH The intrinsic viscosity [η] at is obtained, and based on the obtained intrinsic viscosity [η] and the standard intrinsic viscosity [η]0, the shrinkage factor g’ = [η] / [η]0 is calculated. The standard intrinsic viscosity [η]0 is the calculated value of the intrinsic viscosity of a conjugate diene polymer without a branched structure, which is calculated and used by the following formula. [η]0 = 10 -3.883 ×M 0.771 Among them, M is the absolute molecular weight, and the unit of [η]0 is dl / g. In the case of a distribution having a single peak in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the medium molecular weight fraction MID , and the molecular weight on the low molecular weight side among the molecular weights having an intensity half of the peak intensity showing the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the low molecular weight fraction LOW , and the molecular weight on the high molecular weight side among the molecular weights having an intensity half of the peak intensity showing the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the high molecular weight fraction HIGH , In the case of a bimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, and in such a way that the peak area on the low molecular weight side is larger, in the peak on the low molecular weight side with a large peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the medium molecular weight fraction MID , in the peak on the high molecular weight side with a small peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the high molecular weight fraction HIGH , in the peak on the low molecular weight side with a large peak area, the molecular weight on the low molecular weight side among the molecular weights at which the intensity is half of the peak intensity at the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the low molecular weight fraction LOW , In the case of a bimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, and in such a way that the peak area on the high molecular weight side is larger, in the peak on the high molecular weight side with a large peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the middle molecular weight fraction MID , in the peak on the low molecular weight side with a small peak area, the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the low molecular weight fraction LOW , in the peak on the high molecular weight side with a large peak area, the molecular weight on the high molecular weight side among the molecular weights at which the intensity is half of the peak intensity at the molecular weight at which the molecular weight distribution shows a maximum is taken as the molecular weight Mp_ of the high molecular weight fraction HIGH , In the case of a distribution having a trimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, the molecular weights at which the three existing molecular weight distributions show maxima are taken as the molecular weight Mp_ of the low molecular weight fraction, LOW the molecular weight Mp_ of the medium molecular weight fraction, MID and the molecular weight Mp_ of the high molecular weight fraction HIGH , respectively, starting from the low molecular weight side. In the case of a mode having a distribution with four or more peaks in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, a combination in which the sum of the peak areas of three consecutive peaks is the largest is selected. For the three consecutive peaks thus selected, starting from the low molecular weight side, the molecular weights at which the molecular weight distribution shows a maximum are taken as the molecular weight Mp_ of the low molecular weight fraction, LOW the molecular weight Mp_ of the medium molecular weight fraction, MID and the molecular weight Mp_ of the high molecular weight fraction, HIGH , The adsorption rate of the high molecular weight fraction to silica and the adsorption rate of the medium molecular weight fraction to silica are determined as follows: The conjugated diene polymer is subjected to GPC measurement using a styrene column and GPC measurement using a silica column, and based on these results, it is determined according to the following formula (1). Adsorption rate of silica (%) = (1 - (area A of this material measured by GPC using a silica-based column Si / area B of standard polystyrene measured by GPC using a silica-based column Si )) × (area B of standard polystyrene measured by GPC using a styrene-based column sty / area A of this material measured by GPC using a styrene-based column sty )) × 100 (1) In the case of a conjugate diene polymer having a unimodal distribution in the molecular weight distribution measured by gel permeation chromatography, the adsorption rate of the medium molecular weight fraction to silica is determined by separately obtaining the area A OW between Mp_L HIGH and Mp_ Si , A sty . Using the obtained areas A Si , A sty , it is calculated by the above formula (1). The adsorption rate of the high molecular weight fraction to silica is determined by separately obtaining the area A HIGH between Mp_ 1％_HIGH and Mp_ Si , A sty . Using the obtained areas A Si , A sty , it is calculated by the above formula (1). The Mp_ 1％_HIGH is the molecular weight on the high molecular weight side among the molecular weights at an intensity of 1 / 100 of the maximum intensity, In the case of a bimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, and in such a manner that the peak area on the low molecular weight side is larger, the adsorption rate of the medium molecular weight component to silica is determined by separately obtaining Mp_ LOW and showing Mp_ MID and Mp_ HIGH the molecular weight Mp_ 谷 between the minima between and the area A Si 、A sty , using the obtained area A Si 、A sty , calculated by the above formula (1), the adsorption rate of the high molecular weight component to silica is determined by separately obtaining the molecular weight Mp_ MID showing the minimum between Mp_ HIGH and Mp_ 谷 and the area A _1％_HIGH between Mp Si 、A sty , using the obtained area A Si 、A sty , calculated by the above formula (1), In the case of a bimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography and with a larger peak area on the high molecular weight side, the adsorption rate of the medium molecular weight fraction to silica is determined by separately obtaining the molecular weight Mp_ LOW and Mp_ MID at the minimum value between them, Mp_ 谷 and Mp_ HIGH and the area A Si , A sty . Using the obtained areas A Si , A sty , it is calculated by the above formula (1). The adsorption rate of the high molecular weight fraction to silica is determined by separately obtaining the areas A HIGH between Mp_ _1％_HIGH and Mp Si , A sty . Using the obtained areas A Si , A sty , it is calculated by the above formula (1). In the case of a trimodal distribution in the molecular weight distribution of a conjugated diene polymer measured by gel permeation chromatography, the adsorption rate of the medium molecular weight fraction to silica is determined by separately obtaining the molecular weight Mp LOW between Mp_ MID and the minimum value, and the molecular weight Mp _谷_1 between Mp_ MID and Mp_ HIGH and the minimum value, and the area A _谷_2 between them, and the area A Si and A sty are obtained. Using the obtained areas A Si and A sty , the adsorption rate of the high molecular weight fraction to silica is calculated by the above formula (1). The adsorption rate of the high molecular weight fraction to silica is determined by separately obtaining the molecular weight Mp MID between Mp_ HIGH and the minimum value, and the molecular weight Mp _谷_2 between Mp _1％_HIGH and the area A Si between them, and the area A sty and A Si are obtained. Using the obtained areas A sty , the adsorption rate is calculated by the above formula (1). When the molecular weight distribution of the conjugated diene polymer measured by gel permeation chromatography has a distribution with four or more peaks, the adsorption rate of the medium molecular weight fraction to silica is determined by separately obtaining the molecular weight Mp LOW between Mp_ MID and the minimum value between Mp_ _谷_2 and the molecular weight Mp MID between Mp_ HIGH and the minimum value between Mp_ _谷_3 to obtain the area A Si 、A sty , and using the obtained areas A Si 、A sty , calculated by the above formula (1), the adsorption rate of the high molecular weight fraction to silica is determined by separately obtaining the molecular weight Mp MID between Mp_ HIGH and the minimum value between Mp _谷_3 and Mp _1％_HIGH to obtain the area A Si 、A sty , and using the obtained areas A Si 、A sty , calculated by the above formula (1).

2. The conjugated diene polymer according to claim 1, wherein The shrinkage factor of the medium molecular weight fraction is 0.8 to 1.2, The shrinkage factor of the medium molecular weight fraction is measured as follows: The conjugate diene polymer is measured using a GPC device equipped with a viscosity detector, a light scattering detector, and a differential refractive index detector, and the molecular weight Mp_ of the medium molecular weight fraction is determined from the measurement results. MID The intrinsic viscosity [η] at MID is determined. Based on the obtained intrinsic viscosity [η] and the standard intrinsic viscosity [η]0, the shrinkage factor g’ = [η] / [η]0 is calculated. The standard intrinsic viscosity [η]0 is the calculated value of the intrinsic viscosity of a conjugate diene polymer without a branched structure, which is calculated and used according to the following formula. [η]0 = 10 -3.883 ×M 0.771 where M is the absolute molecular weight, and the unit of [η]0 is dl / g.

3. The conjugated diene polymer according to claim 1 or 2, wherein The adsorption rate of the high molecular weight fraction to silica is 10 to 70%.

4. The conjugated diene polymer according to claim 1 or 2, wherein The conjugated diene polymer has two or more molecular weight peaks.

5. The conjugated diene polymer according to claim 1 or 2, wherein, The conjugated diene polymer is a copolymer having aromatic vinyl monomer units and the conjugated diene monomer units.

6. The conjugated diene polymer according to claim 1 or 2, wherein The molecular weight Mp_ of the low molecular weight substance LOW is in the range of 70,000 to 190,000.

7. A conjugated diene polymer composition containing a filler and the conjugated diene polymer according to any one of claims 1 to 6.

8. A rubber crosslinked product obtained by crosslinking the conjugated diene polymer composition according to claim 7.

9. A tire comprising the rubber crosslinked product according to claim 8.

10. A method for producing a conjugated diene polymer, which is a method for producing the conjugated diene polymer according to any one of claims 1 to 6. In the conjugated diene polymer, based on the total amount of all monomers being 100% by weight, the content ratio of the units of the vinyl compound containing a functional group capable of interacting with silica is 0.001 to 10.000% by weight, and the functional group capable of interacting with silica is a nitrogen atom-containing functional group, a silicon atom-containing functional group, or an oxygen atom-containing functional group. The production method includes the following steps: The first step, in an inert solvent, in the presence of a polymerization initiator, polymerize a monomer containing a conjugated diene compound to obtain a solution containing a polymer chain having a living end; The second step, perform a coupling reaction on a part of the polymer chain having a living end obtained in the first step, thereby forming a coupled polymer chain, and obtain a solution containing the coupled polymer chain and the polymer chain having a living end; And The third step, after performing the coupling reaction in the second step, further polymerize a monomer containing a conjugated diene compound with the polymer chain having a living end. In at least one of the first step and the third step, as the monomer for polymerization, use a monomer containing, in addition to the conjugated diene compound, a vinyl compound, wherein the vinyl compound is a vinyl compound containing a functional group capable of interacting with silica.

11. The method for producing a conjugated diene polymer according to claim 10, wherein, An additional amount of a polymerization initiator is added at any one of the following times: during the polymerization in the first step, at the initiation of the polymerization in the third step, and during the polymerization in the third step.

Images