Conjugated diene polymers, rubber compositions, rubber crosslinks, and tires

Abstract

Provided is a conjugated diene-based polymer containing at least a conjugated diene monomer unit, wherein: the ionic strength index is at least 25%; the number of peaks in a molecular weight distribution curve obtained through gel permeation chromatography measurement is at least 2; and when, among the peaks in the molecular weight distribution curve, a peak having a maximum peak area ratio is defined as a first peak, and a peak having a second largest peak area ratio is defined as a second peak, the molecular weight distribution (Mw / Mn) of the whole conjugated diene-based polymer is at least 1.50, the molecular weight distribution (Mw / Mn) of the first peak is at most 1.30, and the molecular weight distribution (Mw / Mn) of the second peak is at most 1.30.

Description

[Technical Field]

[0001] The present invention relates to a conjugated diene polymer, a rubber composition, a rubber crosslinked product, and a tire, and more particularly to a conjugated diene polymer that can provide a rubber crosslinked product with excellent processability and excellent strength properties, wear resistance properties, and fuel efficiency properties, and to a rubber composition, rubber crosslinked product, and a tire obtained using such a conjugated diene polymer. [Background technology]

[0002] In recent years, with growing concern for environmental issues, polymers used in automobile tires are also required to have excellent fuel efficiency characteristics. Tires obtained using a rubber composition in which silica is compounded as a filler into a conjugated diene polymer exhibit improved low heat generation compared to tires obtained using conventionally used rubber compositions containing carbon black, thus resulting in tires with superior fuel efficiency characteristics.

[0003] As a conjugated diene polymer used to provide such tires, Patent Document 1 discloses a modified conjugated diene polymer that satisfies the following conditions (I) to (IV). (I) The molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement has at least two peaks. (II) In the molecular weight distribution curve, when the peak with the highest molecular weight is designated as peak (B), and the peak with the largest peak area excluding peak (B) is designated as peak (T), the peak molecular weight of peak (B) is 500,000 to 2,500,000, and the peak molecular weight of peak (T) is 150,000 to 600,000. (III) In the molecular weight distribution curve, when the total area is set to 100%, the area of ​​peak (T) is 30% to 80%, and the sum of the areas of peak (B) and peak (T) is 65% or more. (IV) In the molecular weight distribution curve, the proportion of modified polymer chains included from the low molecular weight side to the point where the area is 5% is between 60% and 99%. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2018 / 056025 [Overview of the project] [Problems that the invention aims to solve]

[0005] The conjugated diene polymer obtained by the technology described in Patent Document 1 above lacks sufficient processability, and the rubber crosslinked product obtained using it has room for improvement in terms of strength characteristics, wear resistance characteristics, and fuel efficiency characteristics.

[0006] The present invention has been made in view of the above problems, and aims to provide a conjugated diene polymer that can provide a rubber crosslinked product with excellent processability and excellent strength characteristics, wear resistance characteristics, and fuel efficiency characteristics. The present invention also aims to provide a rubber composition, a rubber crosslinked product, and a tire obtained using such a conjugated diene polymer. [Means for solving the problem]

[0007] As a result of diligent research to achieve the above objective, the present inventors have found that the above objective can be achieved by a conjugated diene polymer having two or more peaks in the molecular weight distribution curve, and in which the overall molecular weight distribution (Mw / Mn), the molecular weight distribution of the first peak having the largest peak area ratio in the molecular weight distribution curve (Mw / Mn), and the molecular weight distribution of the second peak having the second largest peak area ratio in the molecular weight distribution curve (Mw / Mn) are within a specific range, and the ionic strength index is within a specific range. Based on this, the present invention has been completed.

[0008] In other words, according to the present invention, a conjugated diene polymer containing at least conjugated diene monomer units, The ion strength index is 25% or higher. The molecular weight distribution curve obtained by gel permeation chromatography has two or more peaks. If, among the peaks in the molecular weight distribution curve, the peak with the largest peak area ratio is designated as the first peak, and the peak with the second largest peak area ratio is designated as the second peak, A conjugated diene polymer is provided, having an overall molecular weight distribution (Mw / Mn) of 1.50 or higher, a molecular weight distribution (Mw / Mn) of the first peak of 1.30 or lower, and a molecular weight distribution (Mw / Mn) of the second peak of 1.30 or lower.

[0009] In the conjugated diene polymer of the present invention, it is preferable that the peak top molecular weight of the first peak is 3.5 times or more the peak top molecular weight of the second peak. In the conjugated diene polymer of the present invention, it is preferable that the peak area ratio of the first peak to the entire molecular weight distribution curve exceeds 50%. In the conjugated diene polymer of the present invention, it is preferable that the peak-top molecular weight of the first peak is 550,000 or more.

[0010] Furthermore, the present invention provides a rubber composition containing the above-mentioned conjugated diene polymer and a filler. Furthermore, the present invention provides a crosslinked rubber product obtained by crosslinking the above-mentioned rubber composition, and a tire containing such a crosslinked rubber product. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a conjugated diene polymer that can provide a rubber crosslinked product with excellent processability and excellent strength characteristics, wear resistance characteristics, and fuel efficiency characteristics. Furthermore, according to the present invention, it is also possible to provide a rubber composition, a rubber crosslinked product, and a tire obtained using such a conjugated diene polymer. [Modes for carrying out the invention]

[0012] <Conjugated diene polymers> The conjugated diene polymer of the present invention is a conjugated diene polymer containing at least conjugated diene monomer units, The ion strength index is 25% or higher. The molecular weight distribution curve obtained by gel permeation chromatography has two or more peaks. If, among the peaks in the molecular weight distribution curve, the peak with the largest peak area ratio is designated as the first peak, and the peak with the second largest peak area ratio is designated as the second peak, The molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer is 1.50 or higher, the molecular weight distribution (Mw / Mn) of the first peak is 1.30 or lower, and the molecular weight distribution (Mw / Mn) of the second peak is 1.30 or lower.

[0013] The conjugated diene polymer of the present invention contains conjugated diene monomer units. Examples of conjugated diene compounds for forming these 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.

[0014] In the conjugated diene polymer of the present invention, the lower limit of the content of conjugated diene monomer units is greater than 0% by weight, but from the viewpoint of wear resistance and low fuel consumption characteristics of the resulting rubber crosslinked product, the content is preferably 25% by weight or more, more preferably 35% by weight or more, even more preferably 45% by weight or more, particularly preferably 55% by weight or more, and most preferably 65% ​​by weight or more, with the total amount of all monomer units being 100% by weight. On the other hand, the upper limit of the content of conjugated diene monomer units is less than 100% by weight, but from the viewpoint of processability of the conjugated diene polymer, the preferred upper limit is preferably 95% by weight or less, more preferably 90% by weight or less, even more preferably 85% by weight or less, and particularly preferably 80% by weight or less, with the total amount of all monomer units being 100% by weight.

[0015] In the conjugated diene polymer of the present invention, the amount of vinyl bond in the conjugated diene monomer unit is preferably 1 to 90 mol%, more preferably 10 to 80 mol%, even more preferably 20 to 70 mol%, even more preferably 25 to 65 mol%, particularly preferably 30 to 60 mol%, and most preferably 30 to 44 mol%. By setting the vinyl bond content in the conjugated diene monomer unit within the above range, the low fuel consumption characteristics of the resulting rubber crosslinked product can be further enhanced.

[0016] Furthermore, the conjugated diene polymer of the present invention is preferably a copolymer having aromatic vinyl monomer units in addition to conjugated diene monomer units. Examples of aromatic vinyl monomers for forming aromatic vinyl monomer units include styrene, methylstyrene, ethylstyrene, t-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, and vinylnaphthalene. Among these, styrene is preferred.

[0017] In the conjugated diene polymer of the present invention, the upper limit of the content of aromatic vinyl monomer units may be less than 100% by weight. However, from the viewpoint of the wear resistance and low fuel consumption characteristics of the resulting rubber crosslinked product, the content is preferably 75% by weight or less, more preferably 65% ​​by weight or less, even more preferably 55% by weight or less, particularly preferably 45% by weight or less, and most preferably 35% by weight or less, with the total amount of all monomer units being 100% by weight. On the other hand, the lower limit of the content of aromatic vinyl monomer units may be 0% by weight or more. However, from the viewpoint of the processability of the conjugated diene polymer, the preferred lower limit is preferably 5% by weight or more, more preferably 10% by weight or more, even more preferably 15% by weight or more, and particularly preferably 20% by weight or more, with the total amount of all monomer units being 100% by weight.

[0018] Furthermore, the conjugated diene polymer of the present invention may contain, in addition to conjugated diene monomer units and optionally aromatic vinyl monomer units, units of vinyl compounds containing functional groups capable of interacting with silica.

[0019] The vinyl compound containing a functional group that can interact with silica, used to form a unit of a vinyl compound containing a functional group that can interact with silica, is not particularly limited to any compound containing a functional group that can interact with silica and a vinyl group. Here, a functional group that can interact with silica is a functional group that can form a covalent bond between the functional group and the silica surface, or form an intermolecular force weaker than a covalent bond (e.g., ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.). Such a functional group that can interact with silica is not particularly limited, but examples include nitrogen atom-containing functional groups, silicon atom-containing functional groups, and oxygen atom-containing functional groups, and among these, silicon atom-containing functional groups are preferred from the viewpoint of high interaction with silica.

[0020] As a preferred embodiment of a vinyl compound containing a functional group that can interact with silica, for example, a compound represented by the following general formula (1) can be suitably used as a vinyl compound containing a silicon atom-containing functional group. [ka] In the above general formula (1), X 1 X represents a chemical single bond or a hydrocarbylene group. 2 , X 3 and X 4 Each of these independently represents a substituted amino group, a hydrocarbyloxy group, or a hydrocarbyl group which may have substituents.

[0021] In the above general formula (1), X 1is a chemical single bond or a hydrocarbylene group, preferably a chemical single bond. Examples of the hydrocarbylene group include an alkylene group, an alkenediyl group, an arylene group, or a group in which an arylene group and an alkylene group are bonded. Examples of the alkylene group include a methylene group, an ethylene group, a trimethylene group, etc. Examples of the alkenediyl group include a vinylene group, an ethylene-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 and an alkylene group are bonded include a group in which a phenylene group and a methylene group are bonded, a group in which a phenylene group and an ethylene group are bonded, etc. X 1 When X 1 is a hydrocarbylene group, X

[0022] In the above general formula (1), X 2 , X 3 and X 4 each independently represent a substituted amino group, a hydrocarbyloxy group, or a hydrocarbyl group which may have a substituent. Among X 2 , X 3 and X 4 , it is preferable that at least one is a substituted amino group, and it is more preferable that two of X 2 , X 3 and X 4 are substituted amino groups.

[0023] As the substituted amino group that can constitute X 2 , X 3 and X 4 , a group represented by the following general formula (2) is preferable.

Chemical formula

[0024] R 1 and R 2 Examples of hydrocarbyl groups that can constitute a hydrocarbyl group include linear alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, and n-octyl groups; cyclic alkyl groups such as cyclopentyl and cyclohexyl groups; and aryl groups such as phenyl, benzyl, and naphthyl groups. Among these, linear alkyl groups are preferred, and methyl or ethyl groups are more preferred. R 1 and R 2 If the hydrocarbyl group that can constitute the group has substituents, examples include hydrocarbyl groups having a hydrocarbyloxy group as a substituent. Examples of hydrocarbyl groups having a hydrocarbyloxy group as a substituent include alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, and methoxyethyl groups; and aryloxyalkyl groups such as phenoxymethyl groups.

[0025] R 1 and R 2 Specific examples of trihydrocarbyl silyl groups that can constitute this include trimethylsilyl groups, triethylsilyl groups, and trialkylsilyl groups such as tert-butyldimethylsilyl groups.

[0026] R 1 and R 2 When R is connected to each other, 1 and R2 Examples of hydrocarbylene groups that can constitute R include alkylene groups such as trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, dodecamethylene, and 2,2,4-trimethylhexane-1,6-diyl; and alkenediyl groups such as pentane-2-ene-1,5-diyl. 1 and R 2 If the hydrocarbylene group that can constitute the group contains at least one selected from nitrogen, oxygen, sulfur, and silicon atoms, examples of hydrocarbylene groups containing at least one selected from nitrogen, oxygen, sulfur, and silicon atoms include groups represented by -CH=N-CH=CH-, groups represented by -CH=N-CH2-CH2-, groups represented by -CH2-CH2-O-CH2-CH2-, groups represented by -CH2-CH2-S-CH2-CH2-, groups represented by -CH2-CH2-SiH2-CH2-CH2-, groups represented by -CH2-CH2-SiMe2-CH2-CH2-, and groups represented by -CH2-CH2-SiEt2-CH2-CH2-. R 1 and R 2 is either an alkyl group or R 1 and R 2 It is preferable that these groups are bonded to each other to form an alkylene group, R 1 and R 2 It is more preferably an alkyl group, R 1 and R 2 It is more preferable that the group is a methyl group or an ethyl group.

[0027] In the above general formula (2), R 1 and R 2When is a hydrocarbyl group, specific examples of the group represented by the above general formula (2) include dialkylamino groups such as dimethylamino group, diethylamino group, ethylmethylamino group, di-n-propylamino group, diisopropylamino group, di-n-butylamino group, diisobutylamino group, di-sec-butylamino group, and di-tert-butylamino group; diarylamino groups such as diphenylamino group; and the like. Among these, dialkylamino groups are preferred, and dimethylamino group, diethylamino group, and di-n-butylamino group are more preferred.

[0028] In the above general formula (2), R 1 and R 2 However, in the case of a hydrocarbyl group having a hydrocarbyloxy group as a substituent, specific examples of the group represented by the above general formula (2) include di(methoxymethyl)amino groups, di(ethoxymethyl)amino groups, and other di(alkoxyalkyl)amino groups.

[0029] In the above general formula (2), R 1 and R 2 However, in the case of a trihydrocarbyl silyl group, specific examples of the group represented by the above general formula (2) include bis(trimethylsilyl)amino group, bis(tert-butyldimethylsilyl)amino group, N-trimethylsilyl-N-methylamino group, and other trialkylsilyl group-containing amino groups.

[0030] In the above general formula (2), R 1 and R 2 Specific examples of the group represented by the general formula (2) above, when the two groups are bonded to each other to form a hydrocarbylene group, include 1-trimethyleneimino group, 1-pyrrolidino group, 1-piperidino group, 1-hexamethyleneimino group, 1-heptamethyleneimino group, 1-octamethyleneimino group, 1-decamethyleneimino group, 1-dodecamethyleneimino group, and other 1-alkyleneimino groups.

[0031] In the above general formula (2), R 1 and R 2When these groups are bonded to each other to form a hydrocarbylene group containing a nitrogen atom and / or an oxygen atom, specific examples of the group represented by the above general formula (2) include the 1-imidazolyl group, the 4,5-dihydro-1-imidazolyl group, and the morpholino group.

[0032] The group represented by the above general formula (2) is preferably a dialkylamino group or a 1-alkyleneimino group, more preferably a dialkylamino group, and even more preferably a dimethylamino group, a diethylamino group, or a di-n-butylamino group.

[0033] In the above general formula (1), X 2 , X 3 and X 4 Examples of hydrocarbyloxy groups that can constitute a hydrocarbyloxy group include alkoxy groups such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, and tert-butoxy groups; and aryloxy groups such as phenoxy and benzyloxy groups.

[0034] In the above general formula (1), X 2 , X 3 and X 4 Examples of hydrocarbyl groups that can constitute this include alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl groups; and aryl groups such as phenyl, 4-methyl-1-phenyl, and benzyl groups. X 2 , X 3 and X 4 If the hydrocarbyl group that can constitute the compound has substituents, examples include hydrocarbyl groups having a hydrocarbyloxy group as substituents, and alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, and ethoxyethyl groups.

[0035] In the above general formula (1), X 1 X is a chemical single bond, 2 , X 3 and X 4Specific examples of vinyl compounds containing a silicon atom-containing functional group represented by the above general formula (1), in which one of the groups is a substituted amino group, include (dimethylamino)dimethylvinylsilane, (ethylmethylamino)dimethylvinylsilane, (di-n-propylamino)dimethylvinylsilane, (diisopropylamino)dimethylvinylsilane, (dimethylamino)diethylvinylsilane, (ethylmethylamino)diethylvinylsilane, (di-n-propylamino)diethylvinylsilane, (diisopropylamino)diethylvinylsilane, and other (dialkylamino)dialkylvinylsilanes; [bis(trimethylsilyl)amino]dimethylvinylsilane, [bis(t-butyldimethylsilyl)amino]dimethylvinylsilane, [bis(trimethylsilyl)amino]diethylvinylsilane, and other [bis(t-butyldimethylsilyl)amino]diethylvinylsilane, and other [bis(t-butyldimethylsilyl)amino]diethylvinylsilane, and other [bis(t-butyldimethylsilyl)amino]diethylvinylsilane, and other [bis(t-butyldimethylsilyl)amino]diethylvinylsilane, and other [bis(t-) Examples include (trialkylsilyl)amino]dialkylvinylsilanes; (dimethylamino)di(methoxymethyl)vinylsilane, (dimethylamino)di(methoxyethyl)vinylsilane, (dimethylamino)di(ethoxymethyl)vinylsilane, (dimethylamino)di(ethoxyethyl)vinylsilane, (diethylamino)di(methoxymethyl)vinylsilane, (diethylamino)di(methoxyethyl)vinylsilane, (diethylamino)di(ethoxymethyl)vinylsilane, (diethylamino)di(ethoxyethyl)vinylsilane, (diethylamino)di(ethoxyethyl)vinylsilane, and other (dialkylamino)di(alkoxyalkyl)vinylsilanes; and cyclic aminodialkylvinylsilane compounds such as pyrrolidinodimethylvinylsilane, piperidinodimethylvinylsilane, hexamethyleneiminodimethylvinylsilane, 4,5-dihydroimidazolyldimethylvinylsilane, and morpholinodimethylvinylsilane.

[0036] In the above general formula (1), X 1 is a hydrocarbylene group, X 2 , X 3 and X 4Specific examples of vinyl compounds containing a silicon atom-containing functional group represented by the above general formula (1), where one of the groups is a substituted amino group, include (dimethylamino)dimethyl-4-vinylphenylsilane, (dimethylamino)dimethyl-3-vinylphenylsilane, (diethylamino)dimethyl-4-vinylphenylsilane, (diethylamino)dimethyl-3-vinylphenylsilane, (di-n-propylamino)dimethyl-4-vinylphenylsilane, (di-n-propylamino)dimethyl-3-vinylphenylsilane, (di-n-butylamino)dimethyl-4-vinylphenylsilane, and (di-n-butylamino)dimeth Examples include (dialkylamino)dialkylvinylphenylsilanes such as (di-3-vinylphenylsilane), (dimethylamino)diethyl-4-vinylphenylsilane, (dimethylamino)diethyl-3-vinylphenylsilane, (diethylamino)diethyl-4-vinylphenylsilane, (diethylamino)diethyl-3-vinylphenylsilane, (di-n-propylamino)diethyl-4-vinylphenylsilane, (di-n-propylamino)diethyl-3-vinylphenylsilane, (di-n-butylamino)diethyl-4-vinylphenylsilane, and (di-n-butylamino)diethyl-3-vinylphenylsilane.

[0037] In the above general formula (1), X 1 X is a chemical single bond, 2 , X 3 and X 4Specific examples of vinyl compounds containing silicon atom-containing functional groups 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, and bis[bis(tert-butyldimethylsilyl)amino]ethylvinylsilane. Examples include bis[bis(trialkylsilyl)amino]alkylvinylsilanes; bis(dimethylamino)methoxymethylvinylsilane, bis(dimethylamino)methoxyethylvinylsilane, bis(dimethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane, bis(dimethylamino)methoxymethylvinylsilane, bis(diethylamino)methoxyethylvinylsilane, bis(diethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane, 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(cyclicamino)alkylvinylsilane compounds; and so on.

[0038] In the above general formula (1), X 1 is a hydrocarbylene group, X 2 , X 3 and X 4Among them, when two of them are substituted amino groups, specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) 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, and bis(dialkylamino)alkylvinylphenylsilanes such as these.

[0039] In the above general formula (1), X 1 is a chemical single bond, and among X 2 , X 3 and X 4 When three of them are substituted amino groups, specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) include tris(dimethylamino)vinylsilane, tris(diethylamino)vinylsilane, tris(di-n-propylamino)vinylsilane, tris(di-n-butylamino)vinylsilane, and tris(dialkylamino)vinylsilanes such as these.

[0040] In the above general formula (1), X 1 is a hydrocarbylene group, and X 2 , X 3 and X 4Among them, when three of them are substituted amino groups, specific examples of the vinyl compound containing a silicon atom-containing functional group represented by the above general formula (1) 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, and tris(dialkylamino)vinylphenylsilanes such as these.

[0041] In the above general formula (1), X 1 is a chemical single bond, and among X 2 , X 3 and X 4 when none of them is a substituted amino group, 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, tripropoxyvinylsilane; dialkoxyalkylvinylsilanes such as methyldimethoxyvinylsilane, methyldiethoxyvinylsilane; dialkoxyarylvinylsilanes such as di(tert-pentoxy)phenylvinylsilane, di(tert-butoxy)phenylvinylsilane; monoalkoxydialkylvinylsilanes such as dimethylmethoxyvinylsilane; monoalkoxydiarylvinylsilanes such as tert-butoxydiphenylvinylsilane, tert-pentoxydiphenylvinylsilane; monoalkoxyalkylarylvinylsilanes such as tert-butoxymethylphenylvinylsilane, tert-butoxyethylphenylvinylsilane; substituted alkoxyvinylsilane compounds such as tris(β-methoxyethoxy)vinylsilane; and the like.

[0042] Among the compounds represented by the above general formula (1), those in which X 1 is a chemical single bond are preferred, and X1 is a chemical single bond, and X 2 , X 3 and X 4 Of these, compounds in which two are substituted amino groups are more preferred, X 1 is a chemical single bond, and X 2 , X 3 and X 4 Of these, compounds in which two are dialkylamino groups are particularly preferred.

[0043] Among the compounds represented by the above general formula (1), bis(dimethylamino)methylvinylsilane, bis(diethylamino)methylvinylsilane, and bis(di-n-butylamino)methylvinylsilane are preferred, and bis(diethylamino)methylvinylsilane is particularly preferred.

[0044] In addition, vinyl compounds containing functional groups that can interact with silica, other than the compound represented by the general formula (1) above, include bis(trialkylsilyl)aminostyrenes such as 4-N,N-bis(trimethylsilyl)aminostyrene and 3-N,N-bis(trimethylsilyl)aminostyrene; and bis(trialkylsilyl)aminoalkylstyrenes such as 4-bis(trimethylsilyl)aminomethylstyrene, 3-bis(trimethylsilyl)aminomethylstyrene, 4-bis(trimethylsilyl)aminoethylstyrene, and 3-bis(trimethylsilyl)aminoethylstyrene.

[0045] Furthermore, when a compound represented by the above general formula (1) is used as the vinyl compound containing a functional group capable of interacting with silica, a unit represented by the following general formula (3) will be introduced into the conjugated diene polymer of the present invention as the unit of the vinyl compound containing a functional group capable of interacting with silica. [ka] In the above general formula (3), X 5 X represents a chemical single bond or a hydrocarbylene group. 6 , X 7 and X8 Each of these independently represents a hydroxyl group, a substituted amino group, a hydrocarbyloxy group, or a hydrocarbyl group which may have a substituent.

[0046] Furthermore, in the unit represented by the general formula (3) above, X 5 X in the compound represented by the general formula (1) above. 1 Corresponding to the unit represented by the general formula (3) above, X 6 , X 7 and X 8 X in the compound represented by the general formula (1) above. 2 , X 3 and X 4 This corresponds to each of the above general formulas (3). Therefore, in the unit represented by the above general formula (3), X 5 , X 6 , X 7 and X 8 X in the compound represented by the general formula (1) above. 1 , X 2 , X 3 and X 4 These can be considered the same as the above. Also, as a compound represented by the above general formula (1), X 2 , X 3 and X 4 If at least one of them is a substituted amino group or a hydrocarbyloxy group, the substituted amino group or hydrocarbyloxy group is hydrolyzed at any step and timing, resulting in X 2 , X 3 and X 4 At least one of these can be a hydroxyl group.

[0047] In the conjugated diene polymer of the present invention, the content of units of the vinyl compound containing a functional group that can interact with silica is preferably 0.001 to 10.000% by weight, and more preferably 0.001 to 3.000% by weight, with the total amount of all monomer units being 100% by weight. By setting the content of units of the vinyl compound containing a functional group that can interact with silica within the above range, it is possible to improve the fuel efficiency of the resulting rubber crosslinked product while maintaining sufficient processability.

[0048] Furthermore, the conjugated diene polymer of the present invention may contain other monomer units other than conjugated diene monomer units, aromatic vinyl monomer units, and vinyl compound units containing functional groups that can interact 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; and non-conjugated diene compounds such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene.

[0049] In the conjugated diene polymer of the present invention, the bonding mode of each monomer unit can be various, such as block-like, tapered, or random, but a random bonding mode is preferred. By using a random bonding mode, the low fuel consumption characteristics of the resulting rubber crosslinked product can be further enhanced.

[0050] Furthermore, the conjugated diene polymer of the present invention is preferably one that contains a modified group obtained by modifying the end of the polymer chain of the conjugated diene polymer with a modifying agent.

[0051] As a modifying group, it is preferable to use one that contains a functional group that can interact with silica, from the viewpoint of appropriately increasing the affinity to fillers such as silica and further improving the wear resistance and fuel efficiency of the resulting rubber crosslinked product. Here, a functional group that can interact with silica is a functional group that can form a covalent bond between the functional group and the silica surface, or form an intermolecular force weaker than a covalent bond (e.g., ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.). As the interaction formed between silica and the functional group, a covalent bond or an intermolecular force weaker than a covalent bond (e.g., ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.) is preferred, and a weak intermolecular force (e.g., ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.) is more preferred from the viewpoint of easily controlling the ionic strength index within a suitable range. Functional groups that can interact with silica are not particularly limited, but include nitrogen atom-containing functional groups, silicon atom-containing functional groups, and oxygen atom-containing functional groups.

[0052] From the viewpoint of making it easier to control the ionic strength index within a suitable range, nitrogen atom-containing modifying agents are preferred as modifying agents for forming modifying groups. For example, hydrocarbyloxysilane compounds containing nitrogen atoms can be suitably used as nitrogen atom-containing modifying agents.

[0053] A nitrogen atom-containing hydrocarbyloxysilane compound is a silicon-containing compound having at least one nitrogen atom-containing group and at least one hydrocarbyloxy group. While there are no particular limitations on such nitrogen atom-containing hydrocarbyloxysilane compounds, compounds represented by the following general formula (4) can be suitably used. [ka] In the above general formula (4), R 3 is a hydrocarbyl group, and A 1 This is a hydrocarbyloxy group, and A2 A is a group containing a nitrogen atom, where p is an integer from 0 to 2, q is an integer from 1 to 3, r is an integer from 1 to 3, and p+q+r=4. 2 The nitrogen atom-containing group represented by may include a primary amino group having an active hydrogen atom and / or a secondary amino group having an active hydrogen atom, or it may be any other nitrogen atom-containing group.

[0054] Specific examples of compounds represented by the above general formula (4) are not particularly limited, but for example, A in general formula (4) 2 However, as a compound containing a primary amino group having an active hydrogen atom and / or a secondary amino group having an active hydrogen atom, A is a compound such as 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropylmethyldiethoxysilane, and 3-aminopropyltriethoxysilane. 2 Examples include compounds having a 3-aminopropyl group; such as 4-aminobutyldimethylmethoxysilane, 4-aminobutylmethyldimethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyldimethylethoxysilane, 4-aminobutylmethyldiethoxysilane, and 4-aminobutyltriethoxysilane. 2 Examples include compounds having a 4-aminobutyl group; such as 3-(2-aminoethylamino)propyldimethylmethoxysilane, 3-(2-aminoethylamino)propylmethyldimethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, 3-(2-aminoethylamino)propyldimethylethoxysilane, 3-(2-aminoethylamino)propylmethyldiethoxysilane, and 3-(2-aminoethylamino)propyltriethoxysilane. 2 Examples include compounds having a 3-(2-aminoethylamino)propyl group; and so on.

[0055] Also, A in general formula (4) 2However, as a compound whose group is other than a group containing a primary amino group having an active hydrogen atom and / or a secondary amino group having an active hydrogen atom, A is a compound such as 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-dimethylaminopropyldimethylmethoxysilane, 3-dimethylaminopropyltriethoxysilane, 3-dimethylaminopropylmethyldiethoxysilane, and 3-dimethylaminopropyldimethylethoxysilane. 2 Examples include compounds having a 3-dimethylaminopropyl group; such as [3-(diethylamino)propyl]trimethoxysilane, 3-diethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyldimethylmethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-diethylaminopropylmethyldiethoxysilane, and 3-diethylaminopropyldimethylethoxysilane. 2 Examples include compounds having a 3-diethylaminopropyl group; such as 3-dipropylaminopropyltrimethoxysilane, 3-dipropylaminopropylmethyldimethoxysilane, 3-dipropylaminopropyldimethylmethoxysilane, 3-dipropylaminopropyltriethoxysilane, 3-dipropylaminopropylmethyldiethoxysilane, and 3-dipropylaminopropyldimethylethoxysilane. 2 Examples include compounds having a 3-dipropylaminopropyl group; such as 3-dibutylaminopropyltrimethoxysilane, 3-dibutylaminopropylmethyldimethoxysilane, 3-dibutylaminopropyldimethylmethoxysilane, 3-dibutylaminopropyltriethoxysilane, 3-dibutylaminopropylmethyldiethoxysilane, and 3-dibutylaminopropyldimethylethoxysilane. 2 Examples include compounds having a 3-dibutylaminopropyl group; such as 3-phenylmethylaminopropyltrimethoxysilane, 3-phenylmethylaminopropylmethyldimethoxysilane, 3-phenylmethylaminopropyldimethylmethoxysilane, 3-phenylmethylaminopropyltriethoxysilane, 3-phenylmethylaminopropylmethyldiethoxysilane, and 3-phenylmethylaminopropyldimethylethoxysilane.2 Examples include compounds having a 3-phenylmethylaminopropyl group; such as 3-(4-methylpiperazinyl)propyltrimethoxysilane, 3-(4-methylpiperazinyl)propylmethyldimethoxysilane, 3-(4-methylpiperazinyl)propyldimethylmethoxysilane, 3-(4-methylpiperazinyl)propyltriethoxysilane, 3-(4-methylpiperazinyl)propylmethyldiethoxysilane, and 3-(4-methylpiperazinyl)propyldimethylethoxysilane. 2 Examples include compounds having a 3-(4-methylpiperazinyl)propyl group;

[0056] A 2 Examples include compounds having an N,N-bis(trimethylsilyl)aminopropyl group; such as N,N-bis(triethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldimethoxysilane, and N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane. 2 Examples include compounds having an N,N-bis(triethylsilyl)aminopropyl group; such as N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, and N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane. 2 Examples include compounds having an N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyl group.

[0057] Furthermore, as a hydrocarbyloxysilane compound containing a nitrogen atom, compounds represented by the following general formula (5) can also be suitably used. [ka] In the above general formula (5), A 3 is a hydrocarbyl oxy group, R 4 R represents a hydrocarbon group which may have substituents, 5 and R 6 Each of these independently represents a hydrocarbon group which may have substituents, and R 5 and R 6 These atoms may bond to each other, forming a ring structure with the nitrogen atom to which they bond. In the case of forming such a ring structure, they may also form the ring structure with heteroatoms other than the nitrogen atom to which they bond. s is an integer between 0 and 2.

[0058] As a compound represented by the above general formula (5), particularly preferred is R 5 and R 6 Examples include compounds in which hydrocarbon groups represented by are bonded to each other, forming a piperazine ring structure together with the nitrogen atoms to which they are bonded. More specifically, compounds represented by the following general formula (6) are particularly preferred. By using a compound having such a structure as the compound represented by general formula (5), the fuel efficiency characteristics of the resulting rubber crosslinked product can be further improved. [ka] In the above general formula (6), A 3 , R 4 , and s all represent the same things as in the general formula (5) above, R 7 This represents a hydrocarbon group.

[0059] Specific examples of compounds represented by the above general formula (5) include 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, 2,2-diethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane, 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silacyclooctane, and 2-methoxy-2-methyl-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silacyclooctane. These compounds represented by general formula (5) may be used individually or in combination of two or more.

[0060] Among hydrocarbyloxysilane compounds containing nitrogen atoms, the compound represented by the above general formula (4) is preferred because it can further enhance the processability of the conjugated diene polymer, the wear resistance and fuel efficiency of the resulting rubber crosslinked product in a well-balanced manner.

[0061] Furthermore, it is also preferable to use a carbonyl group-containing compound that contains a nitrogen atom as the nitrogen atom-containing modifying agent. A carbonyl group-containing compound that contains a nitrogen atom is a compound having at least one nitrogen atom-containing group and at least one carbonyl group. While there are no particular limitations on such a carbonyl group-containing compound that contains a nitrogen atom, compounds represented by the following general formula (7) can be suitably used. [ka] In the above general formula (7), R 8 , R 9 Each of these independently represents a hydrocarbyl group which may have substituents, and R 10 represents a hydrocarbylene group, R 11 This represents a hydrocarbyl group which may have substituents, or a hydrogen atom. 4 This refers to a chemical single bond, an oxygen atom, or -NR. 12 -(R 12 ) represents a hydrocarbyl group or a hydrogen atom. R 8 , R9 Some of these may bond with each other to form a hydrocarbylene group which may have a nitrogen atom and / or an oxygen atom. 11 R 8 or R 9 It may also form a hydrocarbylene group that, by bonding with a portion of it, may have a nitrogen atom and / or an oxygen atom.

[0062] R 8 , R 9 , R 11 The optionally substituent hydrocarbyl group in this context is a hydrocarbyl group or a substituted hydrocarbyl group. Examples of substituted hydrocarbyl groups include a hydrocarbyl group substituted with a hydrocarbyloxy group and a hydrocarbyl group substituted with a substituted amino group.

[0063] Examples of hydrocarbyl groups include alkyl groups, alkenyl groups, alkynyl groups, aryl groups, and aralkyl groups. Preferred alkyl groups are those having 1 to 12 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-octyl, n-dodecyl, cyclopentyl, and cyclohexyl groups. Preferred alkenyl groups are those having 2 to 12 carbon atoms, such as vinyl, allyl, 1-propenyl, and isopropenyl groups. Preferred alkynyl groups are those having 2 to 12 carbon atoms, such as ethynyl and 2-propynyl groups. Preferred aryl groups are those having 6 to 12 carbon atoms, such as phenyl, methylphenyl, ethylphenyl, benzyl, tolyl, and xylyl groups. Preferred aralkyl groups are those having 7 to 13 carbon atoms, such as benzyl groups.

[0064] Examples of hydrocarbyl groups substituted with hydrocarbyloxy groups include alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, and ethoxyethyl groups.

[0065] Examples of hydrocarbyl groups substituted with substituted amino groups include (N,N-dialkylamino)alkyl groups such as N,N-dimethylaminomethyl, 2-(N,N-dimethylamino)ethyl, 2-(N,N-diethylamino)ethyl, 3-(N,N-dimethylamino)propyl, and 3-(N,N-diethylamino)propyl; (N,N-dialkylamino)aryl groups such as 4-(N,N-dimethylamino)phenyl, 3-(N,N-dimethylamino)phenyl, 4-(N,N-diethylamino)phenyl, and 3-(N,N-diethylamino)phenyl; and 4-(N,N-dimethylamino)methylphenyl and 4-[2-(N,N-dimethylamino) Examples include (N,N-dialkylamino)alkylaryl groups such as [(N)ethyl]phenyl group; alkyl groups substituted with cyclic amino groups such as 3-(1-pyrrolidinyl)propyl group, 3-(1-piperidinyl)propyl group, and 3-(1-imidazolyl)propyl group; aryl groups substituted with cyclic amino groups such as 4-(1-pyrrolidinyl)phenyl group, 4-(1-piperidinyl)phenyl group, and 4-(1-imidazolyl)phenyl group; and alkylaryl groups substituted with cyclic amino groups such as 4-[2-(1-pyrrolidinyl)ethyl]phenyl group, 4-[2-(1-piperidinyl)ethyl]phenyl group, and 4-[2-(1-imidazolyl)ethyl]phenyl group.

[0066] R 10Examples of hydrocarbylene groups include alkylene groups, alkenediyl groups, arylene groups, or arylene-alkylene groups. Examples of alkylene groups include methylene groups, ethylene groups, propylene groups, tetramethylene groups, pentamethylene groups, hexamethylene groups, heptamethylene groups, octamethylene groups, and 2,2,4-trimethylhexane-1,6-diyl groups. Examples of alkenediyl groups include pentane-2-ene-1,5-diyl groups. Examples of arylene groups include phenylene groups, naphthylene groups, and biphenylene groups. Examples of arylene-alkylene groups include phenylene-alkylene groups, naphthylene-alkylene groups, and biphenylene-alkylene groups.

[0067] In the above general formula (7), A 4 This refers to a chemical single bond, an oxygen atom, or -NR. 12 -(R 12 ) represents a hydrocarbyl group or a hydrogen atom. 4 is an oxygen atom, or -NR 12 -(R 12 represents a hydrocarbylene group or a hydrogen atom having 1 to 5 carbon atoms. Preferably, it is a group represented by ), more preferably an oxygen atom or a group represented by -NH-, and even more preferably a group represented by -NH-.

[0068] The compound represented by the above general formula (7) is A 4 Examples of compounds in which the atom is an oxygen atom include 2-(dihydrocarbylamino)ethyl acrylates such as 2-(dimethylamino)ethyl acrylate and 2-(diethylamino)ethyl acrylate; 3-(dihydrocarbylamino)propyl acrylates such as 3-(dimethylamino)propyl acrylate; 2-(dihydrocarbylamino)ethyl methacrylates such as 2-(dimethylamino)ethyl methacrylate and 2-(diethylamino)ethyl methacrylate; and 3-(dihydrocarbylamino)propyl methacrylates such as 3-(dimethylamino)propyl methacrylate.

[0069] Furthermore, as a compound represented by the above general formula (7), A 4 ga-NR 12 -(R 12 ) represents a hydrocarbyl group or hydrogen atom. Examples of compounds that are N-(2-dimethylaminoethyl)acrylamide, N-(2-diethylaminoethyl)acrylamide, etc. N-(2-dihydrocarbylaminoethyl)acrylamide; N-(3-dimethylaminopropyl)acrylamide, N-(3-diethylaminopropyl)acrylamide, etc. N-(3-dihydrocarbylaminopropyl)acrylamide; N-(4-dimethylaminobutyl)acrylamide, N-(4-diethylaminobutyl)acrylamide, etc. N-(2- Examples include N-(2-dihydrocarbylaminoethyl)methacrylamide such as dimethylaminoethyl)methacrylamide and N-(2-diethylaminoethyl)methacrylamide; N-(3-dihydrocarbylaminopropyl)methacrylamide such as N-(3-dimethylaminopropyl)methacrylamide and N-(3-diethylaminopropyl)methacrylamide; and N-(4-dihydrocarbylaminobutyl)methacrylamide such as N-(4-dimethylaminobutyl)methacrylamide and N-(4-diethylaminobutyl)methacrylamide.

[0070] The conjugated diene polymer of the present invention has two or more peaks in the molecular weight distribution curve obtained by gel permeation chromatography (hereinafter sometimes referred to as GPC), and when the peak with the largest peak area ratio in the molecular weight distribution curve is designated as the first peak P1 and the peak with the second largest peak area ratio as the second peak P2, the molecular weight distribution of the entire conjugated diene polymer (Mw / Mn), the molecular weight distribution of the first peak P1 (Mw / Mn), and the molecular weight distribution of the second peak P2 (Mw / Mn) are controlled to a specific range. Note that the number of peaks in the molecular weight distribution curve may be two or more, three or more, or within the range of 3 to 6.

[0071] The number of peaks in the molecular weight distribution curve can be determined by the following procedure. Specifically, a sample solution containing a conjugated diene polymer and an internal standard polystyrene with a molecular weight of 5000 is subjected to GPC measurement using a styrene column. From the obtained molecular weight distribution curve, the region with a molecular weight of less than 5000 is removed, and further, the peak of the internal standard polystyrene is removed to obtain the molecular weight distribution curve of the conjugated diene polymer. The obtained molecular weight distribution curve of the conjugated diene polymer is then divided into regions that are sandwiched between the baseline or minimum value and have one maximum value. The peak area of ​​each divided region is determined, and the number of regions with a peak area of ​​1% or more when the total peak area of ​​the molecular weight distribution curve of the conjugated diene polymer is set to 100% can be determined as the number of molecular weight peaks. The specific measurement conditions can be those described in the examples below. The peak area is determined from the molecular weight distribution curve obtained by GPC measurement as the integral value of the elution time (in seconds) and the RI (Refractive Index) intensity (in mV) at each elution time.

[0072] Furthermore, the conjugated diene polymer of the present invention has a molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer as "(Mw / Mn) all The molecular weight distribution (Mw / Mn) of the first peak P1, which is the peak with the largest peak area ratio, is defined as "(Mw / Mn) P1 The molecular weight distribution (Mw / Mn) of the second peak P2, which has the second largest peak area ratio, is defined as "(Mw / Mn) P2 If this is the case, the overall molecular weight distribution (Mw / Mn) all The molecular weight distribution (Mw / Mn) of the first peak P1 is 1.50 or higher. P1 The molecular weight distribution (Mw / Mn) of the second peak P2 is 1.30 or less. P2 The molecular weight distribution (Mw / Mn) is in the range of 1.30 or less. According to the present invention, these molecular weight distributions (Mw / Mn) all (Mw / Mn) P1 (Mw / Mn) P2By setting the above range and the ionic strength index described later to 25% or higher, the conjugated diene polymer can be made into a rubber crosslinked material that has excellent processability and excellent strength properties, wear resistance properties, and low fuel consumption properties.

[0073] In particular, the inventors have found that by making the conjugated diene polymer have two or more peaks, making the molecular weight distribution (Mw / Mn) of the two peaks with the largest peak areas relatively small (i.e., making the molecular weight distribution sharp), while making the overall molecular weight distribution (Mw / Mn) above a predetermined value (making the overall molecular weight distribution relatively large), and furthermore, by making the ionic strength index, which will be described later, above a predetermined value, the conjugated diene polymer can be made into a rubber crosslinked material that has excellent processability and excellent strength properties, wear resistance properties, and low fuel consumption properties.

[0074] Molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer all The molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer is 1.50 or higher, preferably 1.6 to 3.5, and more preferably 1.7 to 3.0. all If the molecular weight is too small, when compounding agents are added and a compound is formed, the compound will become granular and disorganized, resulting in poor processability, and the resulting rubber crosslinked material will have inferior properties. Molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer. all This can be determined by calculating the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the entire conjugated diene polymer from the molecular weight distribution curve obtained by GPC measurement using a styrene column, in terms of standard polystyrene equivalent, and then calculating the ratio of these two values.

[0075] Also, the molecular weight distribution (Mw / Mn) of the first peak P1. P1The ratio is 1.30 or less, preferably 1.25 or less, more preferably 1.20 or less, and its lower limit is not particularly limited, but preferably 1.00 or more, more preferably 1.05 or more. Also, the molecular weight distribution (Mw / Mn) of the second peak P2 is P2 The ratio is 1.30 or less, preferably 1.25 or less, more preferably 1.20 or less, and even more preferably 1.10 or less. The lower limit is not particularly limited, but is preferably 1.00 or more, and more preferably 1.02 or more. Molecular weight distribution (Mw / Mn) of the first peak P1. P1 Alternatively, the molecular weight distribution (Mw / Mn) of the second peak P2. P2 If the silica content is too large, the dispersibility of silica within the entire conjugated diene polymer becomes insufficient, resulting in poor processability and, furthermore, insufficient improvement in the fuel efficiency characteristics of the resulting rubber crosslinked material.

[0076] Molecular weight distribution (Mw / Mn) of the first peak P1 P1 This can be determined by the following method. First, the peak with the maximum peak area ratio is identified from the molecular weight distribution curve obtained by GPC measurement using a styrene column, and this is extracted as the first peak P1. Then, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in the region corresponding to the first peak P1 (i.e., the region sandwiched between the baseline or minimum value, and having the maximum value corresponding to the first peak P1) are calculated on a standard polystyrene basis, and the ratio of these values ​​is calculated to determine the molecular weight.

[0077] Also, the molecular weight distribution (Mw / Mn) of the second peak P2. P2This can be determined by the following method. First, the peak with the second largest peak area ratio is identified from the molecular weight distribution curve obtained by GPC measurement using a styrene column, and this is extracted as the second peak P2. Then, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) in the region corresponding to the second peak P2 (i.e., the region sandwiched between the baseline or local minimum and having the local maximum corresponding to the second peak P2) are calculated on a standard polystyrene basis, and the ratio of these values ​​is calculated to determine the second peak P2.

[0078] Furthermore, while either the first peak P1 or the second peak P2 may be the peak on the higher molecular weight side, from the viewpoint of providing a rubber crosslinked polymer with better processability and superior strength, wear resistance, and fuel efficiency, it is preferable that the first peak P1 is the peak on the higher molecular weight side than the second peak P2, that is, the peak top molecular weight Mp _P1 (The molecular weight corresponding to the maximum value of the first peak) is the peak top molecular weight Mp of the second peak P2. _P2 It is preferable that the peak top molecular weight Mp is greater than (i.e., the molecular weight corresponding to the maximum value of the second peak), and the peak top molecular weight Mp of the first peak P1. _P1 However, the molecular weight at the top of the second peak P2 is Mp _P2 It is more preferable that it be 3.5 times or more, more preferably 4.5 times or more, and even more preferably 5.5 to 10 times.

[0079] Peak top molecular weight Mp _P1 While not particularly limited, it is preferably 550,000 or more, more preferably 600,000 or more, even more preferably 700,000 to 1,500,000, and especially preferably 800,000 to 1,200,000. Also, the peak top molecular weight Mp of the second peak P2. _P2 The peak top molecular weight Mp is not particularly limited, but is preferably 50,000 to 500,000, more preferably 80,000 to 400,000, even more preferably 100,000 to 300,000, and especially preferably 110,000 to 200,000. _P1 , Mp _P2This can be calculated on a standard polystyrene basis from the molecular weight distribution curve obtained by GPC measurement using the styrene-based column described above.

[0080] Furthermore, the first peak P1 should be the one with the largest peak area ratio in the molecular weight distribution curve of the conjugated diene polymer, but the peak area ratio of the first peak P1 in the entire molecular weight distribution curve is preferably 50% or more, more preferably 51-80%, and even more preferably 52-75%. By setting the peak area ratio of the first peak P1 within the above range, the conjugated diene polymer can be made into a rubber crosslinked product with better processability, strength properties, wear resistance properties, and low fuel consumption properties.

[0081] Furthermore, the second peak P2 only needs to be the second highest in terms of peak area ratio in the molecular weight distribution curve of the conjugated diene polymer. However, the peak area ratio of the second peak P2 in the overall molecular weight distribution curve is preferably 10-50%, more preferably 15-48%, even more preferably 20-48%, and particularly preferably 25-43%.

[0082] The overall weight-average molecular weight (Mw) of the conjugated diene polymer of the present invention is not particularly limited, but is preferably 200,000 to 3,000,000, more preferably 300,000 to 2,000,000, even more preferably 400,000 to 1,500,000, and particularly preferably 420,000 to 800,000.

[0083] In this invention, the conjugated diene polymer has two or more peaks in the molecular weight distribution curve, and the overall molecular weight distribution (Mw / Mn) all , Molecular weight distribution (Mw / Mn) of the first peak P1 P1 , and the molecular weight distribution (Mw / Mn) of the second peak P2. P2Methods for ensuring that the above-mentioned molecular weight distribution is within the specified range are not particularly limited, but include, for example, adding a polymerization initiator during polymerization when synthesizing a conjugated diene polymer by polymerizing a monomer mixture, performing a coupling reaction on the polymer chain obtained by polymerization, and blending two or more conjugated diene polymers having different molecular weight distribution curves. These methods may be used in combination. Among these, the overall molecular weight distribution (Mw / Mn) all , Molecular weight distribution (Mw / Mn) of the first peak P1 P1 , and the molecular weight distribution (Mw / Mn) of the second peak P2. P2 From the viewpoint of being able to more effectively control the properties, when synthesizing a conjugated diene polymer, it is preferable to add a polymerization initiator during the polymerization process and to perform a coupling reaction on the polymer chain obtained by polymerization. Furthermore, from the viewpoint of being able to more effectively control the peak top molecular weight and peak area ratio of the first peak P1 and the second peak P2, it is preferable to add a polymerization initiator during the polymerization process when synthesizing a conjugated diene polymer.

[0084] Furthermore, the conjugated diene polymer of the present invention has an ionic strength index of 25% or higher. Here, the ionic strength index is a value calculated according to the following formula (I) based on the results of gel permeation chromatography (GPC) measurements using a styrene column (hereinafter sometimes referred to as "GPC measurement") and GPC measurements using a cation exchange column for a sample solution containing the conjugated diene polymer and internal standard polystyrene (molecular weight 5000). Ionic strength index (%) = {1 - (A CX / B CX )×(B sty / A sty )} × 100 (I) A CX Peak area of ​​molecular weight distribution curve of conjugated diene polymers measured by GPC using a cation exchange column. B CX Peak area of ​​the internal standard polystyrene peak measured by GPC using a cation exchange column. Bsty Peak area of ​​the internal standard polystyrene peak measured by GPC using a styrene-based column. A sty Peak area of ​​molecular weight distribution curve of conjugated diene polymers measured by GPC using a styrene column. Here, A CX and A sty In the definition, the peak area of ​​the molecular weight distribution curve of a conjugated diene polymer refers to the peak area of ​​the molecular weight distribution curve obtained by removing the region with a molecular weight of less than 5000 from the obtained molecular weight distribution curve, and further removing the peak of the internal standard polystyrene. Furthermore, columns using styrene-divinylbenzene-based gel packing materials are defined as styrene-based columns.

[0085] Furthermore, GPC measurements using styrene columns and GPC measurements using cation exchange columns can be performed under the conditions described in the examples below. Additionally, if the conjugated diene polymer contains impurities such as oil, this may cause errors in the measured ionic strength index. In such cases, Soxhlet extraction or other methods may be performed on the conjugated diene polymer to remove impurities before measuring the ionic strength index.

[0086] In GPC measurements using a cation exchange column, ionic interactions occur between some polymer chains in the conjugated diene polymer and the surface of the cation exchange column. Therefore, the greater the proportion of polymer chains that generate ionic interactions in the conjugated diene polymer, and the stronger the ionic interactions of these polymer chains, the lower the peak intensity originating from these polymer chains in the molecular weight distribution curve obtained using a cation exchange column, compared to the molecular weight distribution curve obtained using a styrene column, and the larger the ionic intensity index calculated by equation (I) above.

[0087] In this invention, the ionic strength index of the conjugated diene polymer measured in this manner is set to 25% or higher. This appropriately enhances the dispersibility of silica in the conjugated diene polymer, achieving excellent processability, and furthermore, appropriately enhances the low fuel consumption characteristics of the resulting rubber crosslinked product. In particular, in this invention, the overall molecular weight distribution (Mw / Mn) all , Molecular weight distribution (Mw / Mn) of the first peak P1 P1 , and the molecular weight distribution (Mw / Mn) of the second peak P2. P2 While keeping the above range, the ionic strength index is set to a range of 25% or higher. This effectively suppresses the decrease in processability caused by increasing the ionic strength index (specifically, the problem that when compounding agents are added and the compound is made, the compound becomes a granular, uncohesive substance), while appropriately obtaining the effect of increasing the ionic strength index, namely the effect of improving the dispersibility of silica.

[0088] The conjugated diene polymer of the present invention has an ionic strength index of 25% or more, preferably 30-100%, more preferably 35-95%, and even more preferably 40-90%.

[0089] The ionic strength index can be controlled by adjusting the proportion of polymer chains containing functional groups (e.g., cationic groups such as amino groups) that interact with the cation exchange column in a conjugated diene polymer, the location of these functional groups within the polymer chain (e.g., within the polymer chain or at the polymer chain end), the molecular structure near the functional groups, and the proportion of these functional groups. It is desirable to combine these factors appropriately. For example, the ionic strength index can be controlled by adjusting the type and amount of modifying agent used to introduce modifying groups to the ends of the polymer chains of a conjugated diene polymer.

[0090] The conjugated diene polymer of the present invention preferably has a Mooney viscosity (ML1+4) of 10 to 200, and more preferably 20 to 150. When the Mooney viscosity is within the above range, processability is improved. The Mooney viscosity (ML1+4) is measured at 100°C or 125°C according to JIS K6300-1:2013.

[0091] Furthermore, the conjugated diene polymer of the present invention can be preferably used in a state mixed with a spreading oil, as described later, from the viewpoint of ease of handling. When the conjugated diene polymer is used in a state mixed with a spreading oil, the Mooney viscosity (ML1+4) of the conjugated diene polymer mixed with the spreading oil can be determined as the Mooney viscosity (ML1+4) of the conjugated diene polymer. In this case, the preferred range and measurement conditions for the Mooney viscosity (ML1+4) are the same as those described above.

[0092] <Method for producing conjugated diene polymers> The conjugated diene polymer of the present invention can be obtained, for example, by polymerizing a monomer mixture containing at least a conjugated diene compound in an inert solvent using a polymerization initiator. The conjugated diene polymer of the present invention is preferably polymerized by solution polymerization.

[0093] Examples of conjugated diene compounds included in the monomer mixture are the same as those exemplified above as conjugated diene compounds that can be used to constitute conjugated diene polymers. Furthermore, the monomer mixture may optionally include the aromatic vinyl monomers, vinyl compounds containing functional groups that can interact with silica, and other monomers.

[0094] The inert solvent used in polymerization is not particularly limited as long as it is not inhibited and is commonly used in solution polymerization. Specific examples of inert solvents include linear aliphatic hydrocarbons such as butane, pentane, hexane, heptane, and 2-butene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and cyclohexene; and aromatic hydrocarbons such as benzene, toluene, and xylene. These inert solvents may be used individually or in combination of two or more. The amount of inert solvent used is such that the monomer concentration is, for example, 1 to 50% by weight, preferably 10 to 40% by weight.

[0095] Furthermore, the polymerization initiator used in polymerization is not particularly limited as long as it can polymerize monomer mixtures containing conjugated diene compounds. Specific examples include polymerization initiators that primarily use organoalkali metal compounds, organoalkaline earth metal compounds, and lanthanum series metal compounds as catalysts. Examples of organoalkali metal compounds include organolithium compounds, organosodium compounds, and organokatum compounds. Specifically, examples include organomonolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenithium; organopolyvalent lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, and 1,3,5-tris(lithiomethyl)benzene; organosodium compounds such as sodium naphthalene; and organokatum compounds such as potassium naphthalene. Examples of organic alkaline earth metal compounds include di-n-butylmagnesium, di-n-hexylmagnesium, diethoxycalcium, calcium distearate, di-t-butoxystrontium, diethoxybarium, diisopropoxybarium, diethylmercaptobarium, di-t-butoxybarium, diphenoxybarium, diethylaminobarium, barium distearate, and diketilbarium. Examples of polymerization initiators using lanthanum series metal compounds as the main catalyst include a salt of a lanthanum series metal, such as lanthanum, cerium, praseodymium, neodymium, samarium, or gadolinium, with a carboxylic acid or phosphorus-containing organic acid as the main catalyst, and a polymerization initiator consisting of this and co-catalysts such as alkylaluminum compounds, organoaluminum hydride compounds, and organoaluminum halide compounds. Among these polymerization initiators, organic monolithium compounds and organic polyvalent lithium compounds are preferably used, organic monolithium compounds are more preferably used, and n-butyllithium is particularly preferably used.Furthermore, the organoalkali metal compounds may be reacted beforehand with secondary amine compounds such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, piperidine, hexamethyleneimine, and heptamethyleneimine to be used as organoalkali metal amide compounds. By using organoalkali metal amide compounds as polymerization initiators, the resulting rubber crosslinked products can be made to have better fuel efficiency and wear resistance. These polymerization initiators may be used individually or in combination of two or more.

[0096] The amount of polymerization initiator used can be determined according to the molecular weight distribution curve of the target conjugated diene polymer, but it is usually in the range of 1 to 50 mmol, preferably 1.5 to 20 mmol, and more preferably 2 to 15 mmol per 1000 g of monomer.

[0097] After starting polymerization using a polymerization initiator, a further polymerization initiator may be added to the polymerization system to continue polymerization. The timing and number of times the polymerization initiator is added are not particularly limited and should be determined according to the molecular weight distribution curve of the target conjugated diene polymer. However, the timing of the additional addition is preferably when the polymerization conversion rate reaches 10-90%, and more preferably when it reaches 30-70%. From the viewpoint of excellent processability, vinyl compounds containing functional groups that can interact with silica are preferably copolymerized after the additional addition is completed. The amount of polymerization initiator used per additional addition is not particularly limited and should be determined according to the molecular weight distribution curve of the target conjugated diene polymer. However, it is preferably 1-99 moles, more preferably 1.2-20 moles, per mole of polymerization initiator used at the start of polymerization.

[0098] The polymerization temperature is typically in the range of -80 to +150°C, preferably 0 to 100°C, and more preferably 30 to 90°C. Any polymerization method, such as batch or continuous, can be used, but the batch method is preferred because it allows for easier control of the randomness of the bonding between conjugated diene monomer units and aromatic vinyl monomer units.

[0099] Furthermore, when polymerizing monomer mixtures containing conjugated diene compounds, it is preferable to add a polar compound to the inert organic solvent in order to adjust the vinyl bond content in the conjugated diene monomer units in the resulting conjugated diene polymer. Examples of polar compounds include ether compounds such as dibutyl ether and tetrahydrofuran; tertiary amines such as tetramethylethylenediamine; alkali metal alkoxides; and phosphine compounds. Among these, ether compounds and tertiary amines are preferred, tertiary amines are more preferred, and tetramethylethylenediamine is particularly preferred. These polar compounds may be used individually or in combination of two or more. The amount of polar compound used should be determined according to the desired vinyl bond content, preferably 0.001 to 100 moles, more preferably 0.01 to 10 moles, per mole of polymerization initiator. When the amount of polar compound used is within this range, it is easy to adjust the vinyl bond content in the conjugated diene monomer units, and problems due to deactivation of the polymerization initiator are less likely to occur.

[0100] As described above, a conjugated diene polymer can be obtained in an inert solvent. Furthermore, the conjugated diene polymer obtained in this way usually has active ends.

[0101] A coupling polymer chain may be formed by reacting a conjugated diene polymer containing an active end with a coupling agent. The coupling agent is not particularly limited, but examples include silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, tin tetrachloride, methyltrichlorotin, dimethyldichlorotin, trimethylchlorotin, 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, and 1,6-bis(trichlorosilyl)hexane. The coupling agent can be selected according to the molecular weight distribution curve of the target conjugated diene polymer, but it is preferable to use a coupling agent with three or more functions, and even more preferable to use a coupling agent with four or more functions.

[0102] When using a coupling agent, it is preferable to form a coupling polymer chain by performing a coupling reaction on a portion of the polymer chain having active ends obtained by the polymerization method described above, thereby obtaining a solution containing the polymer chain having active ends and the coupling polymer chain. In this case, there are no particular limitations on the amount of coupling agent used, but it can be selected according to the molecular weight distribution curve of the target conjugated diene polymer. Preferably, it is 0.01 to 0.4 moles, more preferably 0.02 to 0.3 moles, of the coupling agent in terms of functional groups, per mole of polymerization initiator used at the start of polymerization. Upon addition of the coupling agent, the polymer chain having active ends undergoes a coupling reaction at the active ends. As a result, the polymer chain that undergoes the coupling reaction loses its active ends and becomes a polymer chain without active ends, while the polymer chain that does not undergo the coupling reaction retains its active ends.

[0103] It is preferable to convert a conjugated diene polymer into a conjugated diene polymer having a modified group by reacting a modifying agent with the active end contained in the conjugated diene polymer obtained by polymerization, or with the active end that may be contained in the conjugated diene polymer after a coupling reaction. As the modifying agent, the above-mentioned agents can be used as modifying agents for forming the modified group that may be contained in the conjugated diene polymer of the present invention.

[0104] When reacting the above-mentioned modifying agent with the active ends of a conjugated diene polymer, the amount of modifying agent used is not particularly limited, but it is preferably 0.01 to 10.0 moles, more preferably 0.02 to 5.0 moles, and particularly preferably 0.05 to 2.0 moles, as the amount of modifying agent per mole of active ends of the polymer chain having active ends (or, in the case of using an organoalkali metal compound as a polymerization initiator, the amount of modifying agent per mole of metal atoms in the organoalkali metal compound). The above-mentioned modifying agents can be used, and they may be used individually or in combination of two or more.

[0105] Furthermore, there are no particular limitations on the method of reacting the active ends of the conjugated diene polymer with a modifying agent, but one example is to mix the polymer chain having the active ends and the modifying agent in a solvent in which they can be dissolved. The solvent used in this case can be one of those exemplified above as the solvent used for polymerization of the conjugated diene polymer. In this case, it is simpler and preferable to leave the polymer chain having the active ends obtained above in the polymerization solution used for polymerization and add the modifying agent to it. In this case, the modifying agent may be dissolved in the inert solvent used for polymerization as described above and added to the polymerization system, and the concentration of the solution is preferably in the range of 1 to 50% by weight. The reaction temperature is not particularly limited, but is usually 0 to 120°C, and the reaction time is not particularly limited, but is usually 1 minute to 1 hour.

[0106] The timing of adding a denaturing agent to a solution containing polymer chains with active ends is not particularly limited, but it is desirable to add the denaturing agent when the polymerization reaction is not yet complete and the solution containing polymer chains with active ends also contains monomers, more specifically, when the solution containing polymer chains with active ends contains 100 ppm or more, more preferably 300 to 50,000 ppm, of monomers. By adding the denaturing agent in this manner, it is possible to suppress side reactions between the polymer chains with active ends and impurities contained in the polymerization system, thereby enabling good control of the reaction.

[0107] It is preferable to inactivate unreacted active ends of the conjugated diene polymer obtained by polymerization, or any active ends that may remain after reacting with coupling agents or denaturants as needed, by adding an alcohol such as methanol or isopropanol, or a polymerization inhibitor such as water.

[0108] The solution of the conjugated diene polymer obtained by the above method may optionally contain antioxidants such as phenolic stabilizers, phosphorus stabilizers, or sulfur stabilizers. The amount of antioxidant added should be determined appropriately depending on its type. Furthermore, an extensible oil may be added optionally to form an oil-applied rubber. Examples of extensible oils include paraffinic, aromatic, and naphthenic petroleum-based softeners, plant-based softeners, and fatty acids. When using petroleum-based softeners, it is preferable that the content of polycyclic aromatics extracted by the IP346 method (the testing method of THE INSTITUTE PETROLEUM in the UK) is less than 3%. When using an extensible oil, the amount used is usually 5 to 100 parts by weight per 100 parts by weight of the conjugated diene polymer.

[0109] The conjugated diene polymer obtained in this way can then be separated from the reaction mixture by removing the solvent using any method, such as steam stripping or heating the mixture under reduced pressure, to obtain a solid conjugated diene polymer.

[0110] If desired, the conjugated diene polymer of the present invention may be obtained by mixing two or more conjugated diene polymers having different monomer compositions, molecular structures, molecular weight distribution curves, etc. When mixing two or more conjugated diene polymers, they may be mixed in polymer solution form or in solid form, but it is preferable to mix the two or more conjugated diene polymers in solution form. That is, it is more preferable to prepare separate solutions of the two or more conjugated diene polymers to be mixed and then mix each of the prepared solutions.

[0111] <Rubber composition> The rubber composition of the present invention is a composition comprising the conjugated diene polymer of the present invention described above and a filler.

[0112] The rubber composition of the present invention may contain other polymers besides the conjugated diene polymer of the present invention described above. Other polymers include, for example, natural rubber (which may be modified natural rubber such as epoxidized natural rubber (ENR), hydrogenated natural rubber (HNR), deproteinized natural rubber (DPNR), high-purity natural rubber (UPNR), and grafted natural rubber), polyisoprene rubber, emulsion-polymerized styrene-butadiene copolymer rubber, solution-polymerized styrene-butadiene copolymer rubber, polybutadiene rubber (which may be high-cis-BR or low-cis-BR; it may also be polybutadiene rubber containing crystalline fibers made of 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, excluding the conjugated diene polymers mentioned above. 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 individually or in combination of two or more, such as natural rubber and polybutadiene rubber, or natural rubber and styrene-butadiene copolymer rubber.

[0113] In the rubber composition of the present invention, the conjugated diene polymer of the present invention preferably accounts for 10 to 100% by weight of the polymer component in the rubber composition, and particularly preferably accounts for 50 to 100% by weight. By including the conjugated diene polymer of the present invention in the polymer component in such proportions, a better balance can be achieved between the processability of the rubber composition and the wear resistance and fuel efficiency of the resulting crosslinked rubber.

[0114] Examples of fillers include silica, calcium silicate, aluminum silicate, carbon black, calcium carbonate, talc, aluminum hydroxide, alumina, clay, and mica. Among these, carbon black and silica are preferred, with silica being more preferred, because they can further enhance the wear resistance of the resulting crosslinked rubber product. These can be used individually or in combination of two or more.

[0115] Examples of silica include dry-process white carbon, wet-process white carbon, colloidal silica, precipitated silica, calcium silicate, and aluminum silicate. Among these, wet-process white carbon, which mainly consists of hydrated silica, is preferred. Alternatively, a carbon-silica dual-phase filler, in which silica is supported on the surface of carbon black, may be used. These silicas can be used individually or in combination of two or more types. The nitrogen adsorption specific surface area of ​​the silica used (measured by the BET method in accordance with ASTM D3037-81) is preferably 20 to 400 m². 2 / g, more preferably 50-220m 2 / g, particularly preferably 80-170m 2 The concentration is / g. Furthermore, the pH of the silica is preferably 5 to 10.

[0116] Various commercially available silica products can be used as silica. For example, "Hi-Sil210," "Hi-Sil233," and "Hi-Sil243LD" from PPG Industries; "Zeosil 1115MP," "Zeosil 1165MP," and "Zeosil 165GR" from Solvay; "ULTRASIL VN2," "ULTRASIL VN3," "ULTRASIL 7000GR," and "ULTRASIL 9100GR" from EVONIK; and "NIPSIL VN3," "NIPSIL AQ," "NIPSIL ER," and "NIPSIL RS-150" from Tosoh Silica.

[0117] Examples of carbon black include furnace black, acetylene black, thermal black, channel black, and graphite. Examples of channel black include EPC, MPC, and CC. Examples of furnace carbon black include SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF. Examples of thermal black include FT and MT. Carbon black can be used individually or in combination of two or more types.

[0118] The amount of filler blended in the rubber composition of the present invention is preferably 10 to 250 parts by weight, more preferably 15 to 150 parts by weight, even more preferably 20 to 130 parts by weight, and particularly preferably 75 to 100 parts by weight, per 100 parts by weight of the polymer component in the rubber composition. By setting the amount of filler blended within the above range, it is possible to further improve the low fuel consumption characteristics and low fuel consumption characteristics of the resulting crosslinked rubber product in a well-balanced manner while ensuring sufficient processability of the rubber composition.

[0119] The rubber composition of the present invention may further contain a silane coupling agent from the viewpoint of further improving the low fuel consumption characteristics of the resulting crosslinked rubber. The silane coupling agent is not particularly limited, and various silane coupling agents can be used, but in the present invention, sulfide-based, mercapto-based, protected mercapto-based (for example, those 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 suitably used. Specific examples of silane coupling agents include bis(3-(triethoxysilyl)propyl) disulfide, bis(3-triethoxysilylpropyl) trisulfide, bis(3-(triethoxysilyl)propyl) tetrasulfide, γ-mercaptopropyltriethoxysilane, 3-[ Examples include ethoxybis(3,6,9,12,15-pentaoxacosan-1-yloxy)silyl]-1-propanthol, 3-octanoylthio-1-propyl-triethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, γ-trimethoxysilylpropylbenzothiazyltetrasulfide, 3-trimethoxysilylpropylbenzothiazole tetrasulfide, 3-thiocyanatetopropyltriethoxysilane, vinyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-trimethoxysilylpropyl methacrylate monosulfide, γ-glycidoxypropyltriethoxysilane, 3-nitropropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-chloropropyltrimethoxysilane. Additionally, NXT-Z100, NXT-Z30, NXT-Z45, NXT-Z60, NXT-Z45, and NXT from Momentive Performance Materials, and Si69, Si75, and VP Si363 from Evonik DeGussa can also be used. These silane coupling agents can be used individually or in combination of two or more. Alternatively, one or more of these agents may be pre-oligomerized and used in their oligomerized state.The amount of silane coupling agent added is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight, per 100 parts by weight of the filler.

[0120] Furthermore, the rubber composition of the present invention preferably further contains a crosslinking agent. Examples of crosslinking agents include sulfur, sulfur-containing compounds such as sulfur halides, organic peroxides, quinone dioximes, organic polyhydric amine compounds, and alkylphenol resins having methylol groups. Among these, sulfur is preferably used. The amount of 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, per 100 parts by weight of the polymer component in the rubber composition.

[0121] Furthermore, in addition to the above-mentioned components, the rubber composition of the present invention may contain, in addition to the above-mentioned components, compounding agents such as crosslinking promoters, crosslinking activators, antioxidants, surfactants, process oils, plasticizers, lubricants, and tackifiers in the required amounts according to conventional methods.

[0122] 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 crosslinking accelerators include sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiram-based crosslinking accelerators; dithiocarbamate-based crosslinking accelerators; xanthogenic acid-based crosslinking accelerators; and others. Among these, those containing sulfenamide-based crosslinking accelerators are preferred. These crosslinking accelerators can be used individually or in combination of two or more. The amount of crosslinking accelerator added 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, per 100 parts by weight of the polymer component in the rubber composition.

[0123] Examples of crosslinking activators include higher fatty acids such as stearic acid; zinc oxide; and the like. These crosslinking activators can be used individually or in combination of two or more. The amount of crosslinking activator added is preferably 0.05 to 20 parts by weight, and particularly preferably 0.5 to 15 parts by weight, per 100 parts by weight of the polymer component in the rubber composition.

[0124] To obtain the rubber composition of the present invention, each component can be kneaded according to a conventional method. For example, the components, excluding heat-unstable components such as crosslinking agents and crosslinking accelerators, can be kneaded with a conjugated diene polymer, and then the heat-unstable components such as crosslinking agents and crosslinking accelerators can be mixed into the kneaded mixture to obtain the desired composition. The kneading temperature for the components, excluding heat-unstable components, and the conjugated diene polymer is preferably 80 to 200°C, more preferably 120 to 180°C, and the kneading time is preferably 30 seconds to 30 minutes. Furthermore, the mixing of the kneaded mixture with the heat-unstable components is usually carried out after cooling to 100°C or below, preferably 80°C or below.

[0125] <Rubber Crosslinked Products> The rubber crosslinked material of the present invention is obtained by crosslinking the rubber composition of the present invention described above.

[0126] The crosslinked rubber product of the present invention can be manufactured by using the rubber composition of the present invention, molding it using a molding machine corresponding to the desired shape, such as an extruder, injection molding machine, compressor, or roll, and then heating it to perform a crosslinking reaction and fix the shape as a crosslinked rubber product. In this case, crosslinking may be performed either after molding or 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.

[0127] Furthermore, depending on the shape and size of the crosslinked rubber material, even if the surface is crosslinked, the interior may not be sufficiently crosslinked. In such cases, further heating may be performed to carry out secondary crosslinking.

[0128] For heating, you can appropriately select a common method used for crosslinking rubber, such as press heating, steam heating, oven heating, or hot air heating.

[0129] The crosslinked rubber material of the present invention obtained in this manner is obtained using the conjugated diene polymer of the present invention described above, and therefore has excellent fuel efficiency and wear resistance. For this reason, the crosslinked rubber material of the present invention can be used in a variety of applications, such as materials for various parts of a tire, including the cap tread, base tread, carcass, sidewall, and bead; materials for hoses, belts, mats, vibration damping rubber, and other various industrial products; impact resistance modifiers for resins; resin film cushioning agents; shoe soles; rubber shoes; golf balls; toys; and more. In particular, the crosslinked rubber material of the present invention is suitable as a tire material because of its excellent fuel efficiency and wear resistance. [Examples]

[0130] The present invention will be described below based on more detailed examples, but the present invention is not limited to these examples. In the following, "parts" refers to weight unless otherwise specified. Furthermore, the tests and evaluations were carried out according to the following.

[0131] <Styrene unit content, vinyl bond content> The styrene unit content (weight %) and the amount of vinyl bonded in the conjugated diene monomer unit (mol %) are determined according to JIS K6239:2007. 1 This was determined by 1H-NMR spectroscopy.

[0132] <Mooney viscosity of conjugated diene polymers> The Mooney viscosity (ML1+4) of the conjugated diene polymer was measured under the following conditions, in accordance with JIS K6300-1:2013. • Test temperature: 100℃ or 125℃ • Rotor type: L-shaped • Test equipment used: Shimadzu Mooney Viscometer SMV-300J, manufactured by Shimadzu Corporation.

[0133] <Ionic Strength Index> The ionic strength index was calculated based on the following formula (I) using GPC measurements with a styrene column and a cation exchange column for sample solutions containing conjugated diene polymers (A) to (L) and internal standard polystyrene. Ionic strength index (%) = {1 - (A CX / B CX )×(B sty / A sty )} × 100 (I) A CX Peak area of ​​molecular weight distribution curve of conjugated diene polymers measured by GPC using a cation exchange column. B CX Peak area of ​​the internal standard polystyrene peak measured by GPC using a cation exchange column. B sty Peak area of ​​the internal standard polystyrene peak measured by GPC using a styrene-based column. A sty Peak area of ​​molecular weight distribution curve of conjugated diene polymers measured by GPC using a styrene column. Here, A CX and A sty In this definition, the molecular weight distribution curve of a conjugated diene polymer refers to the molecular weight distribution curve obtained by removing the region with a molecular weight of less than 5000 from the obtained molecular weight distribution curve, and further removing the peak of the internal standard polystyrene.

[0134] GPC measurements using styrene-based columns were performed under the following conditions. (GPC equipment and software) (i) Liquid transfer pump: LC-20AD (manufactured by Shimadzu Corporation) (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation) (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation) (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation) (v) Differential refractive index detector (RID): RID-10A (manufactured by Shimadzu Corporation) (vi) System controller: CBM-20A (manufactured by Shimadzu Corporation) (vii) Measurement and analysis software: LC solution ver. 1.24 SP1 (viii) Measurement conditions GPC Columns: Plus Pore Series Poly Pore 7.5mm ID x 300mm (manufactured by Agilent Technologies) 2 tubes Mobile phase: 25 mg of 2-(ethylamino)ethanol (Fujifilm Wako Chemical Co., Ltd., special grade) was added to 3 L of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., special grade, stabilizer-free). Flow rate: 1mL / min Column oven temperature: 35℃ Detection: Differential refractive index detector (RID) RID cell temperature: 35℃ Sample solution injection volume: 100 μL GPC column calibration standard: PStQuick Kit-H (manufactured by Tosoh Corporation) (ix) Sample solution preparation conditions To 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., special grade, stabilizer-free), 5 mg of standard polystyrene A5000 (manufactured by Tosoh Corporation), with a molecular weight of 5000, was added as an internal standard. Sample solution concentration: 0.5 mg / mL Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation) Dissolution conditions: 10 mg of sample and 20 mL of solvent were placed in a screw vial, sealed tightly, and stirred at room temperature for 120 minutes at a stirring speed of 60 strokes / minute using a DF-8020. The mixture was filtered using a syringe fitted with a filtration filter. Filtration filter: Milex-LG, pore size 0.45 μm, hydrophilic, PTFE, filter diameter 25 mm (Merck)

[0135] GPC measurements using cation exchange columns were performed under the following conditions. The measurement solution used for GPC measurements using cation exchange columns was the same as the measurement solution used for GPC measurements using styrene-based columns described above. (GPC equipment and software) (i) Liquid transfer pump: LC-20AD (manufactured by Shimadzu Corporation) (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation) (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation) (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation) (v) Differential refractive index detector (RID): RID-10A (manufactured by Shimadzu Corporation) (vi) System controller: CBM-20A (manufactured by Shimadzu Corporation) (vii) Measurement and analysis software: LC solution ver. 1.24 SP1 (viii) Measurement conditions GPC columns: Inertcil CX (4.6 x 250 mm, GL Sciences) x 2 Mobile phase: Tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., special grade, stabilizer-free) Flow rate: 0.7mL / min Column oven temperature: 35℃ Detection: Differential refractive index detector (RID) RID cell temperature: 35℃ Sample solution injection volume: 100 μL GPC column calibration standard: PStQuick Kit-H (manufactured by Tosoh Corporation) (ix) Sample solution preparation conditions To 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., special grade, stabilizer-free), 5 mg of standard polystyrene A5000 (manufactured by Tosoh Corporation), with a molecular weight of 5000, was added as an internal standard. Sample solution concentration: 0.5 mg / mL Automatic shaker for dissolution: DF-8020 (manufactured by Tosoh Corporation) Dissolution conditions: 10 mg of sample and 20 mL of solvent were placed in a screw vial, sealed tightly, and stirred at room temperature for 120 minutes at a stirring speed of 60 strokes / minute using a DF-8020. The mixture was filtered using a syringe fitted with a filtration filter. Filtration filter: Milex-LG, pore size 0.45 μm, hydrophilic, PTFE, filter diameter 25 mm (Merck)

[0136] <Weight-average molecular weight (Mw), molecular weight distribution (Mw / Mn), number of peaks in the molecular weight distribution curve, peak-top molecular weight of each peak> For sample solutions containing conjugated diene polymers (A) to (L) and internal standard polystyrene, GPC measurements were performed using a styrene column, similar to the measurement of ionic strength indices described above, to obtain molecular weight distribution curves for the conjugated diene polymers. Based on the obtained molecular weight distribution curves of the conjugated diene polymers, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were determined. Note that the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were calculated in terms of polystyrene equivalent. Furthermore, the obtained molecular weight distribution curves of the conjugated diene polymers were divided into regions sandwiched between the baseline or minimum value and having one maximum value. The peak area of ​​each divided region was determined, and the number of regions with a peak area of ​​1% or more when the total peak area of ​​the molecular weight distribution curve of the conjugated diene polymers is set to 100% was determined as the number of molecular weight peaks. Furthermore, for each divided region (limited to regions with a peak area of ​​1% or more), the peak in the region with the lowest molecular weight was defined as "Peak A," the peak in the next lowest molecular weight region as "Peak B," and the peak in the next lowest molecular weight region as "Peak C." Then, the peak top molecular weight (the molecular weight showing the maximum value in each region), the molecular weight distribution (Mw / Mn) of each peak, and the peak area ratio of each peak were determined.

[0137] <Processability (compound cohesion)> The rubber composition after primary kneading was visually observed and evaluated for processability (compound cohesion). Specifically, a glossy, clay-like consistency was marked with a circle (○), while a dull, sandy, and incoherent consistency was marked with a cross (×). The glossier and more cohesive the rubber composition after primary kneading, the better the processability of the conjugated diene polymer.

[0138] <Processability (silica dispersion)> Uncrosslinked rubber compositions were processed to prepare test specimens measuring 3 cm square and weighing approximately 5 g. After preheating the test specimens at 100°C for 4 minutes, the storage modulus G' was measured at dynamic strains of 0.7% and 42% under conditions of 40°C and 10 Hz using a PREMIER RPA (ALPHA TECHNOLOGIES). The difference (ΔG') between the storage modulus G' at 0.7% dynamic strain and the storage modulus G' at 42% dynamic strain was calculated. For the difference (ΔG') in storage modulus G' in each example and comparative example, an index was calculated with the difference (ΔG') in Example 2 set to 100, and this was used as the processability (silica dispersion) value. A larger processability (silica dispersion) value indicates better silica dispersion in the uncrosslinked rubber composition, meaning the conjugated diene polymer has excellent processability.

[0139] <Fuel efficiency characteristics> A rubber crosslinked sheet was punched out into strips 2 mm thick and 40 mm long to obtain test specimens. The loss tangent (tanδ(70°C)) of the obtained test specimens was measured using a viscoelasticity measuring device (manufactured by Ueshima Seisakusho Co., Ltd.) under the conditions of a frequency of 10 Hz, initial elongation of 10%, strain amplitude of 0.25%, and temperature of 70°C. For the loss tangent (tanδ(70°C)) in each example and comparative example, an index was calculated with the loss tangent (tanδ(70°C)) in Example 1 set to 100, and this was used as the value for low fuel consumption characteristics. A larger value for low fuel consumption characteristics indicates that the resulting rubber crosslinked material has superior low fuel consumption characteristics.

[0140] <Strength Characteristics> Using a crosslinked rubber sheet, the tensile strength (MPa) and elongation (%) at fracture were measured under the following conditions in accordance with JIS K6251:2010, and the product of tensile strength and elongation was calculated. For the obtained product of tensile strength and elongation, an index was calculated with the product of tensile strength and elongation in Example 1 set to 100, and this was used as the strength characteristic value. A larger strength characteristic value indicates that the resulting crosslinked rubber has superior strength characteristics. • Specimen preparation method: Sheets are prepared by press crosslinking, followed by punching. • Test specimen shape: Dumbbell-shaped, type 3 • Specimen sampling direction: Parallel to the grain • Number of test specimens: 3 ·Measurement temperature: 23℃ • Test speed: 500 mm / min • Test equipment used: ALPHA TECHNOLOGIES TENSOMETER 10k • Test machine capacity: Load cell type 1kN

[0141] <Wear resistance properties> Test specimens were obtained by molding rubber crosslinked sheets to an outer diameter of 50 mm, an inner diameter of 15 mm, and a thickness of 10 mm. The wear resistance of the obtained test specimens was measured using an FPS wear tester manufactured by Ueshima Seisakusho Co., Ltd., under conditions of a load of 1 kgf and a slip ratio of 7%. For the wear resistance of each example and comparative example, an index was calculated with the wear resistance of Example 1 set to 100, and this was used as the value of the wear resistance characteristic. A higher value of the wear resistance characteristic indicates that the resulting rubber crosslinked material has superior wear resistance.

[0142] <Preparation of polymer block (A) with active ends> 140.8 g of cyclohexane and 3.0 mmol of tetramethylethylenediamine were added to an 800 ml nitrogen-purged container, followed by the addition of 30.0 mmol of n-butyllithium. Then, 113.6 g of isoprene and 9.2 g of styrene were slowly added, and the mixture was reacted in a container at 50°C for 120 minutes to obtain a polymer block (A) with active ends. The obtained polymer block (A) had a weight-average molecular weight (Mw) of 6,500, a molecular weight distribution (Mw / Mn) of 1.10, a styrene monomer unit content of 7.5% by weight, an isoprene monomer unit content of 92.5% by weight, and a vinyl bond content of 7.0 mol%.

[0143] <Manufacturing Example 1> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 12.03 mL of tetrahydrofuran, 3.69 mL of ethylene glycol diethyl ether, 1087 g of 1,3-butadiene, and 416 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 22.06 mmol of n-butyllithium, and polymerization was started at 32°C. Immediately after the start of the polymerization reaction, 1298 g of 1,3-butadiene was added continuously over 160 minutes, and 199 g of styrene was added continuously over 140 minutes. After confirming that the polymerization conversion rate was in the range of 95% to 100%, 1.74 mmol of silicon tetrachloride was added 10 minutes later, and the reaction was allowed to proceed for 15 minutes. Next, 15.11 mmol of [3-(diethylamino)propyl]trimethoxysilane was added and reacted for 15 minutes, then 18.13 mmol of n-butyllithium was added and reacted for another 15 minutes. Subsequently, 1.5 equivalents of methanol relative to the total amount of lithium in the autoclave was added as a polymerization inhibitor to obtain a solution containing the conjugated diene polymer. To this solution, 0.75 parts of 2,4-bis(octylthiomethyl)-6-methylphenol (manufactured by RIANOX, trade name "RIANOX1520") was added as an antioxidant for 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0144] <Manufacturing Example 2> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 13.22 mL of tetrahydrofuran, 2.73 mL of ethylene glycol dibutyl ether, 497 g of 1,3-butadiene, and 452 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that could deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 1.46 mmol of bis(diethylamino)methylvinylsilane. Subsequently, 2.03 mmol of n-butyllithium was added, and polymerization was started at 43°C. Twenty minutes after the start of the polymerization reaction, 755 g of 1,3-butadiene was continuously added over 200 minutes. Then, when the polymerization conversion rate reached 60%, 2.03 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 6.77 mmol of N-(3-dimethylaminopropyl)acrylamide was added 20 minutes later, and the mixture was reacted for 15 minutes. Then, as a polymerization inhibitor, 1.5 equivalents of methanol relative to the total amount of lithium in the autoclave was added to obtain a solution containing the conjugated diene polymer. To this solution, 0.56 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0145] <Manufacturing Example 3> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 13.22 mL of tetrahydrofuran, 2.73 mL of ethylene glycol dibutyl ether, 497 g of 1,3-butadiene, and 452 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 3.65 mmol of bis(diethylamino)methylvinylsilane. Subsequently, 2.24 mmol of n-butyllithium was added, and polymerization was started at 43°C. Twenty minutes after the start of the polymerization reaction, 755 g of 1,3-butadiene was continuously added over 200 minutes. Then, when the polymerization conversion rate reached 60%, 5.23 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 7.47 mmol of N-(3-dimethylaminopropyl)acrylamide was added 20 minutes later, and the mixture was reacted for 15 minutes. Then, as a polymerization inhibitor, 1.5 equivalents of methanol relative to the total amount of lithium in the autoclave was added to obtain a solution containing the conjugated diene polymer. To this solution, 0.56 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0146] <Manufacturing Example 4> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 13.22 mL of tetrahydrofuran, 2.73 mL of ethylene glycol dibutyl ether, 497 g of 1,3-butadiene, and 452 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that could deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 2.03 mmol of n-butyllithium, and polymerization was started at 43°C. Twenty minutes after the start of the polymerization reaction, 755 g of 1,3-butadiene was continuously added over 200 minutes. Subsequently, when the polymerization conversion rate reached 60%, 2.03 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 10.15 mmol of [3-(diethylamino)propyl]trimethoxysilane was added 20 minutes later, and the mixture was reacted for 15 minutes. Then, as a polymerization inhibitor, 1.5 equivalents of methanol relative to the total amount of lithium in the autoclave was added to obtain a solution containing the conjugated diene polymer. To this solution, 0.56 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0147] <Manufacturing Example 5> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 13.22 mL of tetrahydrofuran, 3.09 mL of ethylene glycol dibutyl ether, 497 g of 1,3-butadiene, and 452 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 1.98 mmol of n-butyllithium, and polymerization was started at 43°C. Twenty minutes after the start of the polymerization reaction, 755 g of 1,3-butadiene was continuously added over 200 minutes. Subsequently, when the polymerization conversion rate reached 50%, 7.02 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 20 minutes later, 13.50 mmol of [3-(diethylamino)propyl]trimethoxysilane was added and reacted for 15 minutes, then 20.25 mmol of n-butyllithium was added and reacted for another 15 minutes. After that, as a polymerization inhibitor, 1.5 equivalents of methanol relative to the total amount of lithium in the autoclave was added to obtain a solution containing the conjugated diene polymer. To this solution, 0.56 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0148] <Manufacturing Example 6> In a 20 L autoclave equipped with a stirrer, 8160 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 2340 g of cyclohexane, 8.02 mL of tetrahydrofuran, 0.78 mL of ethylene glycol dibutyl ether, 400 g of 1,3-butadiene, and 600 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 1.36 mmol of n-butyllithium, and polymerization was started at 45°C. Thirty minutes after the start of the polymerization reaction, 500 g of 1,3-butadiene was continuously added over 150 minutes. Subsequently, when the polymerization conversion rate reached 50%, 6.00 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 10 minutes later, 11.04 mmol of [3-(diethylamino)propyl]trimethoxysilane was added and reacted for 20 minutes, followed by the addition of 16.56 mmol of n-butyllithium, and the reaction was continued for another 20 minutes. Then, as a polymerization inhibitor, 2.0 equivalents of methanol relative to the total amount of lithium in the autoclave were added to obtain a solution containing the conjugated diene polymer. To this solution, 0.40 parts and 0.20 parts of 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer GM) and pentaerythrityltetrakis(3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer TP-D) were added to 100 parts of the conjugated diene polymer as antioxidants to obtain a polymer solution.

[0149] <Manufacturing Example 7> In a 20 L autoclave equipped with a stirrer, under a nitrogen atmosphere, 8160 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 2340 g of cyclohexane, 8.02 mL of tetrahydrofuran, 0.75 mL of ethylene glycol dibutyl ether, 452 g of 1,3-butadiene, and 194 g of styrene were charged. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger. Then, 0.99 mmol of piperidine was added and stirred for 1 minute, followed by the addition of 1.98 mmol of n-butyllithium, and polymerization was started at 45°C. Ten minutes after the start of the polymerization reaction, 639 g of 1,3-butadiene was continuously added over 160 minutes. Subsequently, when the polymerization conversion rate reached 50%, 5.80 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 0.39 mmol of silicon tetrachloride was added and the mixture was reacted for 20 minutes. Then, 11.17 mmol of [3-(diethylamino)propyl]trimethoxysilane was added and the mixture was reacted for 20 minutes, followed by the addition of 16.76 mmol of n-butyllithium, and the mixture was reacted for another 20 minutes. Finally, as a polymerization inhibitor, 2.0 equivalents of methanol relative to the total amount of lithium in the autoclave were added to obtain a solution containing the conjugated diene polymer. To this solution, 0.80 parts and 0.40 parts of 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer GM) and pentaerythrityltetrakis(3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer TP-D) were added to 100 parts of the conjugated diene polymer as antioxidants to obtain a polymer solution.

[0150] <Manufacturing Example 8> In a 30 L autoclave equipped with a stirrer, 15,300 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 13.22 mL of tetrahydrofuran, 2.73 mL of ethylene glycol dibutyl ether, 497 g of 1,3-butadiene, and 452 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that could deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 1.97 mmol of n-butyllithium, and polymerization was started at 43°C. Twenty minutes after the start of the polymerization reaction, 755 g of 1,3-butadiene was continuously added over 200 minutes. Subsequently, when the polymerization conversion rate reached 60%, 4.60 mmol of n-butyllithium was added. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 20 minutes later, methanol in an amount equal to 1.5 equivalents relative to the total amount of lithium in the autoclave was added as a polymerization inhibitor to obtain a solution containing the conjugated diene polymer. To this solution, 0.56 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0151] <Manufacturing Example 9> In a 20L autoclave equipped with a stirrer, 7956g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68g / mL), 1014g of cyclohexane, 3.08mm of tetramethylethylenediamine, 425g of 1,3-butadiene, 680g of styrene, and 4.27mm of piperidine were charged under a nitrogen atmosphere. To pre-detoxify impurities that could deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, followed by the addition of 4.27mm of n-butyllithium, and polymerization was started at 55°C. After continuing the polymerization reaction for 15 minutes, 8.54mm of bis(diethylamino)methylvinylsilane was added, and 595g of 1,3-butadiene was continuously added over 85 minutes. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 6.41 mmol of [3-(diethylamino)propyl]trimethoxysilane was added 15 minutes later, and the mixture was reacted for 15 minutes. Then, as a polymerization inhibitor, 2 equivalents of methanol relative to the total amount of lithium in the autoclave were added to obtain a solution containing the conjugated diene polymer. To this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0152] <Manufacturing Example 10> In a 20 L autoclave equipped with a stirrer, 7956 g of industrial hexane, 1014 g of cyclohexane, 2.63 mmol of tetramethylethylenediamine, 425 g of 1,3-butadiene, and 680 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger. Then, 4.38 mmol of the polymer block (A) with active ends obtained above was added (calculated in terms of lithium atom content), and polymerization was started at 55°C. After continuing the polymerization reaction for 15 minutes, 595 g of 1,3-butadiene was continuously added over 85 minutes. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 10 minutes later, 2 equivalents of methanol relative to the total amount of lithium in the autoclave were added as a polymerization termination agent to obtain a solution containing a conjugated diene polymer. To this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0153] <Manufacturing Example 11> In a 20 L autoclave equipped with a stirrer, 9180 g of industrial hexane, 1170 g of cyclohexane, 5.37 mmol of tetramethylethylenediamine, 500 g of 1,3-butadiene, 800 g of styrene, and 2.00 mmol of bis(diethylamino)methylvinylsilane were charged under a nitrogen atmosphere. To pre-detoxify impurities that could deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger. Then, 18.52 mmol of the polymer block (A) with active ends obtained above was added (calculated in terms of lithium atom content), and polymerization was started at 55°C. After continuing the polymerization reaction for 15 minutes, 4.00 mmol of bis(diethylamino)methylvinylsilane was added, and 700 g of 1,3-butadiene was continuously added over 75 minutes. Subsequently, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 10 minutes later, methanol in an amount of 2 equivalents relative to the total amount of lithium in the autoclave was added as a polymerization inhibitor to obtain a solution containing the conjugated diene polymer. To this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol was added as an antioxidant for every 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0154] <Manufacturing Example 12> The polymer solution was obtained by following the same procedure as in Production Example 8, except that the amount of polymer block (A) with active ends was changed to 4.86 mmol when converted to lithium atom content, and 10 minutes after confirming that the polymerization conversion rate was in the range of 95% to 100%, 0.87 mmol of 1,6-bis(trichlorosilyl)hexane was added in the form of a 40 wt% cyclohexane solution, stirred for 20 minutes, and then the polymerization inhibitor was added.

[0155] <Manufacturing Example 13> The polymer solution was obtained by following the same procedure as in Production Example 9, except that the amount of tetramethylethylenediamine added was changed to 4.23 mmol, the amount of polymer block (A) with active ends was changed to 37.74 mmol when converted to lithium atom content, and after confirming that the polymerization conversion rate was in the range of 95% to 100%, a polyorganosiloxane represented by the following formula (8) was added so that the amount of epoxy groups was 24.00 mmol, and after reacting for 10 minutes, a polymerization inhibitor was added. [ka]

[0156] <Manufacturing Example 14> In a 20 L autoclave equipped with a stirrer, 8160 g of industrial hexane (Sumitomo Chemical Co., Ltd., trade name: Hexane (general product), density 0.68 g / mL), 2340 g of cyclohexane, 8.02 mL of tetrahydrofuran, 0.67 mL of ethylene glycol dibutyl ether, 921 g of 1,3-butadiene, and 217 g of styrene were charged under a nitrogen atmosphere. To pre-detoxify impurities that would act to deactivate polymerization, a small amount of n-butyllithium was added to the autoclave as a scavenger, then 3.61 mmol of n-butyllithium was added, and polymerization was started at 40°C. Immediately after the start of polymerization, 1030 g of 1,3-butadiene was continuously added over 170 minutes. After confirming that the polymerization conversion rate was in the range of 95% to 100%, 10 minutes later, 2.0 equivalents of methanol relative to the total amount of lithium in the autoclave was added as a polymerization termination agent to obtain a solution containing a conjugated diene polymer. To this solution, 0.40 parts and 0.20 parts of 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer GM) and pentaerythrityltetrakis(3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumirizer TP-D) were added to 100 parts of the conjugated diene polymer as antioxidants to obtain a polymer solution.

[0157] <Production Example 15> Into an autoclave with a stirrer having an internal volume of 20 L, 8160 g of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: Hexane (general grade), density 0.68 g / mL), 2340 g of cyclohexane, 8.02 mL of tetrahydrofuran, 0.50 mL of ethylene glycol dibutyl ether, 550 g of 1,3-butadiene, and 130 g of styrene were charged under a nitrogen atmosphere. In order to detoxify impurities that act on the deactivation of polymerization in advance, a small amount of normal butyllithium was added to the autoclave as a scavenger, and then 14.40 mmol of the polymer block (A) having an active end obtained above was added in terms of lithium atom content, and polymerization was started at 40°C. Immediately after the start of polymerization, 616 g of 1,3-butadiene was continuously added over 140 minutes. Then, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 14.40 mmol of N-(3-dimethylaminopropyl)acrylamide was added 10 minutes later, and the reaction was carried out for 20 minutes. As a polymerization terminator, 2.0 equivalents of methanol was added to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. To this solution, 0.40 parts and 0.20 parts of 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer GM) and pentaerythrityl tetrakis(3-laurylthiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) were added per 100 parts of the conjugated diene polymer as antioxidants, respectively, to obtain a polymer solution.

[0158] [Examples 1 to 7, Comparative Examples 1 and 5] The blending amounts of each conjugated diene polymer contained in each polymer solution obtained in Production Examples 1 to 8, 14, and 15, and the blending amount of oil (manufactured by JXTG Energy Corporation, trade name "Process NC140") were as shown in Table 1. Each polymer solution obtained in Production Examples 1 to 8, 14, and 15 and the oil were mixed, stirred and mixed until uniform, then spread on a bat, left standing at room temperature for 12 hours, and dried at 65°C in a vacuum dryer for 6.5 hours to remove the solvent, thereby obtaining conjugated diene polymers (A) to (H), (L) (in Examples 1, 6, 7, and Comparative Example 5, no oil was blended). For the obtained conjugated diene polymers (A) to (H), (L), according to the above method, the content of styrene units, the amount of vinyl bonds, Mooney viscosity, ionic strength index, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) of the conjugated diene polymer, the number of peaks in the molecular weight distribution curve, the peak top molecular weight of each peak, the molecular weight distribution (Mw / Mn) of each peak, and the peak area ratio of each peak were measured and evaluated. The results are shown in Table 1.

[0159] [Comparative Examples 2 to 4] The blending amounts of each conjugated diene polymer contained in each polymer solution obtained in Production Examples 9 to 13, and the blending amount of oil (manufactured by Nippon Oil Corporation, trade name "Aromax T-DAE") were as shown in Table 1. Each polymer solution obtained in Production Examples 9 to 13 and the oil were mixed, stirred and mixed until uniform, then the solvent was removed by steam stripping, and dried at 60°C in a vacuum dryer for 24 hours to obtain conjugated diene polymers (I) to (K). For the obtained conjugated diene polymers (I) to (K), the content of styrene units, the amount of vinyl bonds, Mooney viscosity, ionic strength index, weight average molecular weight (Mw), molecular weight distribution (Mw / Mn) of the conjugated diene polymer, the number of peaks in the molecular weight distribution curve, the peak top molecular weight of each peak, the molecular weight distribution (Mw / Mn) of each peak, and the peak area ratio of each peak were measured and evaluated. The results are shown in Table 1.

[0160] [Preparation of Rubber Composition; Examples 1 to 7, Comparative Examples 1 to 5] In a 250 mL laboplast mill, the conjugated diene polymers (A) to (L) from Examples 1 to 7 and Comparative Examples 1 to 5 were kneaded for 30 seconds. Then, each component except sulfur and vulcanization accelerator was added in the proportions shown in Table 2, and the mixture was kneaded for a further 3.5 minutes. The rubber composition after primary kneading was then released from the laboplast mill. The indicated temperature of the laboplast mill at the time of release of the rubber composition after primary kneading was 140°C. The processability (compound cohesion) of the obtained rubber composition after primary kneading was evaluated according to the method described above. The results are shown in Table 2.

[0161] Next, the rubber composition after primary kneading was wound onto an open roll set to 50°C, sulfur and a vulcanization accelerator were added, and these were kneaded to obtain a sheet-like uncrosslinked rubber composition. The processability (silica dispersion) of the obtained uncrosslinked rubber composition was evaluated according to the method described above. The results are shown in Table 2.

[0162] The uncrosslinked rubber composition obtained above was crosslinked by heating at 160°C for 30 to 35 minutes to obtain a crosslinked rubber sheet. The obtained crosslinked rubber sheet was evaluated for fuel efficiency, strength, and abrasion resistance according to the method described above. The results are shown in Table 2.

[0163] [Table 1]

[0164] [Table 2]

[0165] The materials listed in Table 2 are as follows: • Silica: Manufactured by EVONIK, product name "ULTRASIL(R)7000GR" • Oil: Manufactured by Shin Nippon Oil Corporation, product name "Aromax T-DAE" • Silane coupling agent: Bis(3-(triethoxysilyl)propyl) tetrasulfide (manufactured by Degussa, trade name "Si69") • Carbon Black: Manufactured by Cabot Japan, product name "N339" • Zinc oxide: Manufactured by Seido Chemical Industry Co., Ltd., product name "Zinc Oxide Type 2" • Anti-aging agent: 6PPD, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Nocrac 6C") • Stearic acid: Manufactured by NOF Corporation, product name "Beads Stearic Acid Tsubaki" • Sulfur: Manufactured by Tsurumi Chemical Co., Ltd., product name "Sulfur 325 Mesh" • Vulcanization accelerator (1): N-cyclohexyl-2-benzothiadylsulfenamide (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Noxellar CZ-G") • Vulcanization accelerator (2): Diphenylguanidine (manufactured by Ouchi Shinko Chemical Industry Co., Ltd., product name "Noxellar D")

[0166] As shown in Tables 1 and 2, the overall molecular weight distribution (Mw / Mn) all The molecular weight distribution (Mw / Mn) of the first peak P1, where the ratio is 1.50 or higher and the peak area ratio is the largest. P1 The molecular weight distribution (Mw / Mn) of the second peak with the second largest peak area ratio, where the value is 1.30 or less. P2 Conjugated diene polymers having a ratio of 1.30 or less and an ionic strength index of 25% or more were able to provide rubber crosslinked materials with excellent processability and superior strength, wear resistance, and fuel efficiency (Examples 1-7).

[0167] On the other hand, conjugated diene polymers with an ionic strength index of less than 25% exhibited poor silica dispersibility, and the resulting rubber crosslinked products had poor fuel efficiency characteristics (Comparative Examples 1, 3, 5). Overall molecular weight distribution (Mw / Mn) all Conjugated diene polymers with a ratio of less than 1.50 resulted in a compound that was granular and lacked cohesion, exhibiting poor processability. Furthermore, the resulting rubber crosslinked material had inferior strength, wear resistance, and fuel efficiency characteristics (Comparative Example 2). Furthermore, the molecular weight distribution (Mw / Mn) of the second peak, which has the second largest peak area ratio. P2Conjugated diene polymers with a ratio greater than 1.30 exhibited poor silica dispersibility, and the resulting rubber crosslinked products had poor fuel efficiency characteristics (Comparative Example 3).

Claims

1. A conjugated diene polymer containing at least conjugated diene monomer units, It contains at least one of the following: a modified group containing a nitrogen atom-containing functional group and a silicon atom-containing functional group, and a unit of a vinyl compound containing a nitrogen atom-containing functional group and a silicon atom-containing functional group. The ion strength index is 25% or higher. The number of peaks in the molecular weight distribution curve obtained by gel permeation chromatography is two or more. If, among the peaks in the molecular weight distribution curve, the peak with the largest peak area ratio is designated as the first peak, and the peak with the second largest peak area ratio is designated as the second peak, The molecular weight distribution (Mw / Mn) of the entire conjugated diene polymer is 1.50 or higher, the molecular weight distribution (Mw / Mn) of the first peak is 1.30 or lower, and the molecular weight distribution (Mw / Mn) of the second peak is 1.30 or lower. A conjugated diene polymer in which the peak-top molecular weight of the first peak is 5.5 to 10 times that of the peak-top molecular weight of the second peak.

2. The conjugated diene polymer according to Claim 1, wherein the peak top molecular weight of the second peak is 50,000 to 500,000.

3. The conjugated diene polymer according to claim 1 or 2, wherein the peak area ratio of the first peak to the entire molecular weight distribution curve exceeds 50%.

4. The conjugated diene polymer according to claim 1 or 2, wherein the peak-top molecular weight of the first peak is 550,000 or more.

5. A rubber composition comprising a conjugated diene polymer according to claim 1 or 2 and a filler.

6. A crosslinked rubber product obtained by crosslinking the rubber composition described in claim 5.

7. A tire comprising the rubber crosslinking material described in claim 6.

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