Conjugated diene-based polymer, rubber composition, rubber crosslinked product, and tire

Abstract

The present invention provides a conjugated diene-based polymer containing at least a conjugated diene monomer unit, having a silicon content of 95 ppm by weight or more and an ionic strength index of 75% or less.

Description

Technical Field

[0001] This invention relates to conjugated diene polymers, rubber compositions, rubber crosslinks, and tires, and more specifically, to conjugated diene polymers that have excellent processability and can form rubber crosslinks with excellent abrasion resistance and fuel economy, as well as rubber compositions, rubber crosslinks, and tires obtained using such conjugated diene polymers. Background Technology

[0002] In recent years, with increasing attention to environmental issues, there is a growing demand for polymer compositions used in automobile tires that offer superior fuel economy. Tires made using rubber compositions incorporating silica as a filler in conjugated diene polymers exhibit improved low-heat properties compared to tires made using conventional rubber compositions incorporating carbon black, thus enabling the production of tires with even better fuel economy.

[0003] As a conjugated diene polymer for forming such tires, Patent Document 1 discloses a conjugated diene polymer that satisfies (1) to (4) below.

[0004] (1) The molecular weight distribution curve obtained by gel permeation chromatography (GPC) has more than two peaks.

[0005] (2) The above molecular weight distribution curve contains a peak (A) with a molecular weight of 500,000 to 2,500,000 and a peak (B) with a molecular weight of 150,000 to 600,000.

[0006] (3) The sum of the areas of the above peak (A) and the above peak (B) is more than 70% of the total area of ​​the above molecular weight distribution curve.

[0007] (4) The absolute value of the difference between the glass transition temperature (Tg(A)) of the conjugated diene polymer contained in the above peak (A) and the glass transition temperature (Tg(B)) of the conjugated diene polymer contained in the above peak (B) is 2℃~30℃.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent document 1: International Publication No. 2018 / 147312. Summary of the Invention

[0011] The problem the invention aims to solve

[0012] The processability of the conjugated diene polymer obtained by the technology of the aforementioned Patent Document 1 is not sufficient. Furthermore, the rubber crosslinks obtained using the conjugated diene polymer have room for improvement in terms of abrasion resistance and fuel economy.

[0013] This invention was made in view of the above-mentioned problems, and its object is to provide a conjugated diene polymer that exhibits excellent processability and is capable of forming rubber crosslinks with excellent abrasion resistance and fuel economy. Furthermore, this invention aims to provide rubber compositions, rubber crosslinks, and tires obtained using such conjugated diene polymers.

[0014] Solution for solving the problem

[0015] In order to achieve the above objectives, the inventors conducted in-depth research and found that the above objectives could be achieved by setting the silicon content and ionic strength index of the conjugated diene polymer to a specific range, thus completing the present invention.

[0016] That is, according to the present invention, a conjugated diene polymer can be provided, which contains at least conjugated diene monomer units, has a silicon content of 95 ppm by weight or more, and an ionic strength index of 75% or less.

[0017] In the conjugated diene polymers of the present invention, a molecular weight distribution (Mw / Mn) of 1.5 or higher is preferred.

[0018] In the conjugated diene polymers of the present invention, the weight-average molecular weight (Mw) is preferably 200,000 or more. In the conjugated diene polymers of the present invention, the silicon content is preferably 150 ppm by weight or more.

[0019] In the conjugated diene polymers of the present invention, the ionic strength index is preferably 0.5 to 60%.

[0020] In the conjugated diene polymers of the present invention, it is preferable that the number of peaks in the molecular weight distribution curve is 2 or more.

[0021] The conjugated diene polymers of the present invention preferably contain terminal modified groups.

[0022] According to the present invention, a rubber composition containing a filler and the above-mentioned conjugated diene polymer can be provided.

[0023] Furthermore, according to the present invention, a rubber crosslinker formed by crosslinking the above-described rubber composition and a tire comprising such a rubber crosslinker can be provided.

[0024] Invention Effects

[0025] According to the present invention, a conjugated diene polymer that exhibits excellent processability and can form rubber crosslinks with excellent abrasion resistance and fuel economy can be provided. Furthermore, according to the present invention, rubber compositions, rubber crosslinks, and tires obtained using such conjugated diene polymers can also be provided. Detailed Implementation

[0026] <Conjugated diene polymers>

[0027] The conjugated diene polymer of the present invention contains at least a conjugated diene monomer unit, has a silicon content of 95 ppm by weight or more, and an ionic strength index of 75% or less.

[0028] The conjugated diene polymers of the present invention contain conjugated diene monomer units. Examples of conjugated diene monomers used to form 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. Furthermore, 1,3-butadiene and isoprene may be used in combination.

[0029] The lower limit of the content ratio of conjugated diene monomer units in the conjugated diene polymer of the present invention is only 0% by weight or more. From the viewpoint of the wear resistance and fuel economy of the obtained rubber crosslinked product, it is preferable that the content ratio of all monomers is 20% by weight or more, more preferably 25% by weight or more, further preferably 30% by weight or more, particularly preferably 40% by weight or more, and most preferably 50% by weight or more, with a total monomer content of 100% by weight. On the other hand, the upper limit of the content ratio of conjugated diene monomer units is only 100% by weight or less. From the viewpoint of the processability of the conjugated diene polymer, the preferred upper limit values ​​with a total monomer content of 100% by weight are, in the preferred order, 95% by weight or less, 90% by weight or less, 85% by weight or less, 80% by weight or less, 75% by weight or less, 70% by weight or less, 66% by weight or less, 64% by weight or less, 62% by weight or less, and 60% by weight or less.

[0030] The amount of vinyl bonds in the conjugated diene monomer units of the conjugated diene polymer of the present invention is preferably 1 to 90 mol%, more preferably 3 to 80 mol%, even more preferably 5 to 70 mol%, even more preferably 7 to 60 mol%, particularly preferably 9 to 50 mol%, and most preferably 10 to 40 mol%. By keeping the vinyl bond content in the conjugated diene monomer units within the above range, the fuel economy of the obtained rubber crosslinked product can be further improved.

[0031] Furthermore, the conjugated diene polymer of the present invention is preferably a copolymer having aromatic vinyl monomer units in addition to the conjugated diene monomer units. Examples of aromatic vinyl monomers used to form the aromatic vinyl monomer units include: styrene, methylstyrene, ethylstyrene, tert-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, vinylnaphthalene, etc. Among these, styrene is preferred. The upper limit of the content of aromatic vinyl monomer units in the conjugated diene polymer is only 0% by weight or more. From the viewpoint of the abrasion resistance and fuel economy of the obtained rubber crosslinked product, with a total monomer content of 100% by weight, it is preferably 80% by weight or less, more preferably 75% by weight or less, further preferably 70% by weight or less, particularly preferably 60% by weight or less, and most preferably 50% by weight or less. On the other hand, the lower limit of the content of aromatic vinyl monomer units is only 0% by weight or more. From the viewpoint of the processability of conjugated diene polymers, with the total amount of all monomers being 100% by weight, the preferred lower limit values ​​in the preferred order are 5% by weight or more, 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, 30% by weight or more, 34% by weight or more, 36% by weight or more, 38% by weight or more, and 40% by weight or more.

[0032] In the case where the conjugated diene polymer of the present invention contains aromatic vinyl monomer units, the aromatic vinyl monomer block ratio in the conjugated diene polymer of the present invention is preferably 30.0% or less, more preferably 20.0% or less, further preferably 10.0% or less, and particularly preferably 5.0% or less. The aromatic vinyl monomer block ratio is determined by using deuterated chloroform as a solvent. 1 ¹H-NMR measurements were performed. The peaks from the aromatic vinyl monomers at 6.1–7.7 ppm of the obtained ¹H-NMR spectrum were taken as peaks from the aromatic vinyl monomer blocks. When the peaks from the aromatic vinyl monomer blocks at 6.1–6.88 ppm were taken as peaks from the aromatic vinyl monomer blocks, the ratio of the peak area from the aromatic vinyl monomer blocks to the peak area from the aromatic vinyl monomers was calculated. This value was multiplied by 2.5, and the percentage value was taken as the aromatic vinyl monomer block ratio. When the aromatic vinyl monomer is styrene, a styrene block ratio within the above range is preferred. By keeping the aromatic vinyl monomer block ratio within the above range, a more balanced abrasion resistance and fuel economy can be achieved in the obtained rubber crosslinked product.

[0033] The block size of aromatic vinyl monomers can be controlled by adjusting the timing of adding the conjugated diene monomer and the aromatic vinyl monomer to the polymerization system. The conjugated diene monomer and the aromatic vinyl monomer can be added to the polymerization system at any time, whether before or after the addition of the polymerization initiator.

[0034] Furthermore, in addition to conjugated diene monomer units and aromatic vinyl monomer units as needed, the conjugated diene polymers of the present invention may also contain units of vinyl compounds with functional groups capable of interacting with silicon dioxide.

[0035] The vinyl compound containing a functional group capable of interacting with silicon dioxide, which is used as a unit for forming a vinyl compound containing a functional group capable of interacting with silicon dioxide, is not particularly limited as long as it contains both a functional group capable of interacting with silicon dioxide and a vinyl group. Here, the functional group capable of interacting with silicon dioxide refers to a functional group that can form a covalent bond with the surface of silicon dioxide, or a functional group that can form an intermolecular force weaker than a covalent bond (e.g., ion-dipole interaction, dipole-dipole interaction, hydrogen bond, van der Waals force, etc.). There is no particular limitation on such a functional group capable of interacting with silicon dioxide, and examples include nitrogen-containing functional groups, silicon-containing functional groups, and oxygen-containing functional groups. Among these, silicon-containing functional groups are preferred from the viewpoint of strong interaction with silicon dioxide.

[0036] As a preferred form of vinyl compound containing a functional group capable of interacting with silicon dioxide, a vinyl compound containing a silicon-containing functional group can preferably be a compound represented by, for example, the following general formula (1).

[0037] [Chemical Formula 1]

[0038]

[0039] In the above general formula (1), X 1 X represents a chemical single bond or a hydrocarbon group. 2 X 3 and X 4 Each can independently represent a substituted amino group, a hydrocarbon group, or a hydrocarbon group that may have substituents.

[0040] In the above general formula (1), X 1 It is a chemical single bond or a hydrocarbon group, preferably a chemical single bond. Examples of hydrocarbon groups include alkylene, alkylenediyl, arylene, or groups bonded to alkylene and arylene.

[0041] Examples of alkylene groups include methylene, ethylene, and trimethylene. Examples of alkylene groups include vinylene and ethylene-1,1-diyl. Examples of aryl groups include phenylene, naphthylene, and biphenylene. Examples of groups bonded to alkylene groups include groups bonded to phenylene and methylene, and groups bonded to phenylene and ethylene. In X 1 In the case of a hydrocarbon group, X 1 Preferably arylene, more preferably phenylene.

[0042] In the above general formula (1), X 2 X 3 and X 4 Each can independently represent a substituted amino group, an alkyl group, or a hydrocarbon group that may have substituents. X is preferred. 2 X 3 and X 4 At least one of them is a substituted amino group, preferably X. 2 X 3 and X 4 Two of them are substituted amino groups.

[0043] As a component of X 2 X 3 and X 4 The substituted amino group is preferably represented by the group represented by the following general formula (2).

[0044] R 1 -N(-R 2 )-(2)

[0045] In the above general formula (2), R 1 and R 2 They can be bonded together or not, in R 1 and R 2 In the absence of mutual bonding, R 1 and R 2 Each can independently represent a hydrocarbon group or a trialkylsilyl group that may have substituents, in R 1 With R 2 When they are bonded together, R 1 and R 2 It indicates that it may contain at least one hydrocarbon group selected from nitrogen, oxygen, sulfur and silicon atoms.

[0046] As can constitute R 1 and R 2 Examples of hydrocarbon groups include: chain alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, and n-octyl; cyclic alkyl groups such as cyclopentyl and cyclohexyl; and aryl groups such as phenyl, benzyl, and naphthyl. Among these, chain alkyl groups are preferred, and methyl or ethyl groups are more preferred.

[0047] In the ability to form R 1 and R 2 When a hydrocarbon group has a substituent, examples include hydrocarbon groups with an alkyloxy group as a substituent, such as alkoxyalkyl groups such as methoxymethyl, ethoxymethyl, and methoxyethyl; and aryloxyalkyl groups such as phenoxymethyl.

[0048] As can constitute R 1 and R 2 Specific examples of trialkylsilyl compounds include trimethylsilyl, triethylsilyl, tert-butyldimethylsilyl, and other trialkylsilyl compounds.

[0049] In R 1 With R 2 When they are bonded together, as a form of R 1 and R 2 Examples of alkylene groups include: trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, decamethylene, dodecylene, 2,2,4-trimethylhexane-1,6-diyl, etc.; pentane-2-en-1,5-diyl, etc., etc. Furthermore, in the formation of R... 1 and R 2 When the alkylene group contains at least one selected from nitrogen atom, oxygen atom, sulfur atom and silicon atom, examples of alkylene groups containing at least one selected from nitrogen atom, oxygen atom, sulfur atom and silicon atom include: the group represented by -CH=N-CH=CH-, the group represented by -CH=N-CH2-CH2-, the group represented by -CH2-CH2-O-CH2-CH2-, the group represented by -CH2-CH2-S-CH2-CH2-, the group represented by -CH2-CH2-SiH2-CH2-CH2-, the group represented by -CH2-CH2-SiMe2-CH2-CH2-, the group represented by -CH2-CH2-SiEt2-CH2-CH2-, etc.

[0050] Preferred R 1 and R 2 It is an alkyl group or R 1 With R 2 They bond together to form alkylene groups, more preferably R 1 and R 2 It is an alkyl group, and R is more preferably used. 1 and R 2 It can be methyl or ethyl.

[0051] As R in the above general formula (2) 1 and R 2Specific examples of the groups represented by the above general formula (2) when the group is a hydrocarbon group include: dialkylamino, diethylamino, ethylmethylamino, di-n-propylamino, diisopropylamino, di-n-butylamino, diisobutylamino, di-sec-butylamino, di-tert-butylamino, and other dialkylamino groups; diarylamino, and other diphenylamino groups. Among these, dialkylamino is preferred, and dimethylamino, diethylamino, and di-n-butylamino are more preferred.

[0052] As R in the above general formula (2) 1 and R 2 Specific examples of the groups represented by the above general formula (2) in the case of hydrocarbon groups having hydrocarbon oxygen as a substituent include: di(methoxymethyl)amino, di(ethoxymethyl)amino, and di(alkoxyalkyl)amino, etc.

[0053] As R in the above general formula (2) 1 and R 2 Specific examples of the groups represented by the above general formula (2) in the case of trialkylsilyl groups include: bis(trimethylsilyl)amino, bis(tert-butyldimethylsilyl)amino, N-trimethylsilyl-N-methylamino, and trialkylsilyl amino groups.

[0054] As R in the above general formula (2) 1 With R 2 Specific examples of the groups represented by the above general formula (2) when they are bonded together to form alkylene groups include: 1-trimethyleneimino, 1-pyrrolidinyl, 1-piperidinyl, 1-hexamethyleneimino, 1-heptamethyleneimino, 1-octamethyleneimino, 1-demomethyleneimino, 1-dodecimethyleneimino, and other 1-alkyleneimino groups.

[0055] As R in the above general formula (2) 1 With R 2 Specific examples of the groups represented by the above general formula (2) when they are bonded together to form alkylene groups containing nitrogen atoms and / or oxygen atoms include 1-imidazolyl, 4,5-dihydro-1-imidazolyl, morpholino, etc.

[0056] As the group represented by the above general formula (2), dialkylamino, 1-alkylimino, more preferably dialkylamino, and even more preferably dimethylamino, diethylamino, or di-n-butylamino are preferred.

[0057] In the above general formula (1), as a form that can constitute X 2 X 3 and X 4Examples of alkyl groups include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, etc.; aryloxy groups include phenoxy, benzyloxy, etc.

[0058] In the above general formula (1), as a form that can constitute X 2 X 3 and X 4 Examples of hydrocarbon groups include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, and tert-butyl; and aryl groups such as phenyl, 4-methyl-1-phenyl, and benzyl.

[0059] In the ability to constitute X 2 X 3 and X 4 When the hydrocarbon group has a substituent, examples include hydrocarbon groups with an alkyloxy group as a substituent, such as methoxymethyl, ethoxymethyl, ethoxyethyl, and other alkoxyalkyl groups.

[0060] As X in the above general formula (1) 1 For chemical single bonds, X 2 X 3 and X 4Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) when one of the amino groups is substituted include: (dimethylamino)dimethylvinylsilane, (ethylmethylamino)dimethylvinylsilane, (di-n-propylamino)dimethylvinylsilane, (diisopropylamino)dimethylvinylsilane, (dimethylamino)diethylvinylsilane, (ethylmethylamino)diethylvinylsilane, (di-n-propylamino)diethylvinylsilane, (diisopropylamino)diethylvinylsilane, etc. (dialkylamino)dialkylvinylsilane; [bis(trimethylsilyl)amino]dimethylvinylsilane, [bis(tert-butyldimethylsilyl)amino]dimethylvinylsilane, [bis(trimethylsilyl)amino]diethylvinylsilane, [bis(tert-butyldimethylsilyl)amino]diethylvinylsilane, etc. [Bis(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, etc. (dialkylamino)di(alkoxyalkyl)vinylsilanes; pyrrolidinyl dimethylvinylsilane, piperidinyl dimethylvinylsilane, hexamethyleneimino dimethylvinylsilane, 4,5-dihydroimidazolyl dimethylvinylsilane, morpholinyl dimethylvinylsilane, etc., cyclic amino dialkylvinylsilane compounds, etc.

[0061] As X in the above general formula (1) 1 It is a hydrocarbon group, X 2 X 3 and X 4Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1), where one of the amino groups is substituted, 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 ... (Amino)dimethyl-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, (di-n-butylamino)diethyl-3-vinylphenylsilane, etc. (dialkylamino)dialkylvinylphenylsilane, etc.

[0062] As X in the above general formula (1) 1 For chemical single bonds, X 2 X 3 and X 4Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) in the case where the two amino groups are substituted 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, etc., bis(dialkylamino)alkylvinylsilane; bis[bis(trimethylsilyl)amino]methylvinylsilane, bis[bis(tert-butyldimethylsilyl)amino]methylvinylsilane, bis[bis(trimethylsilyl)amino]ethylvinylsilane, bis[bis(tert-butyldimethylsilyl)amino]ethylvinylsilane, etc. Silanes and other bis[bis(trialkylmethsilyl)amino]alkylvinylsilanes; bis(dimethylamino)methoxymethylvinylsilane, bis(dimethylamino)methoxyethylvinylsilane, bis(dimethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane, bis(diethylamino)methoxymethylvinylsilane, bis(diethylamino)methoxyethylvinylsilane, bis(diethylamino)ethoxymethylvinylsilane, bis(dimethylamino)ethoxyethylvinylsilane, etc., bis(dialkylamino)alkoxyalkylsilanes; bis(pyrrolidinyl)methylvinylsilane, bis(piperidinyl)methylvinylsilane, bis(hexamethyleneimino)methylvinylsilane, bis(4,5-dihydroimidazolyl)methylvinylsilane, bis(morpholinyl)methylvinylsilane, etc., bis(cyclic amino)alkylvinylsilane compounds, etc.

[0063] As X in the above general formula (1) 1 It is a hydrocarbon group, X 2 X 3 and X 4Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) when the two amino groups are substituted are: 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 ... (Amino)methyl-3-vinylphenylsilane, bis(dimethylamino)ethyl-4-vinylphenylsilane, bis(dimethylamino)ethyl-3-vinylphenylsilane, bis(diethylamino)ethyl-4-vinylphenylsilane, bis(diethylamino)ethyl-3-vinylphenylsilane, bis(di-n-propylamino)ethyl-4-vinylphenylsilane, bis(di-n-propylamino)ethyl-3-vinylphenylsilane, bis(di-n-butylamino)ethyl-4-vinylphenylsilane, bis(di-n-butylamino)ethyl-3-vinylphenylsilane, etc., bis(dialkylamino)alkylvinylphenylsilane, etc.

[0064] As X in the above general formula (1) 1 For chemical single bonds, X 2 X 3 and X 4 Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) in the case where the three are substituted amino groups include: tris(dimethylamino)vinylsilane, tris(diethylamino)vinylsilane, tris(di-n-propylamino)vinylsilane, tris(di-n-butylamino)vinylsilane, and tris(dialkylamino)vinylsilane, etc.

[0065] As X in the above general formula (1) 1 It is a hydrocarbon group, X 2 X 3 and X 4 Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) in the case where the three are substituted amino groups include: tris(dimethylamino)-4-vinylphenylsilane, tris(dimethylamino)-3-vinylphenylsilane, tris(diethylamino)-4-vinylphenylsilane, tris(diethylamino)-3-vinylphenylsilane, tris(di-n-propylamino)-4-vinylphenylsilane, tris(di-n-propylamino)-3-vinylphenylsilane, tris(di-n-butylamino)-4-vinylphenylsilane, tris(di-n-butylamino)-3-vinylphenylsilane, and tris(dialkylamino)vinylphenylsilane, etc.

[0066] As X in the above general formula (1)1 For chemical single bonds, X 2 X 3 and X 4 Specific examples of vinyl compounds containing silicon-containing functional groups represented by the above general formula (1) when none of them are substituted amino groups include: trialkoxyvinylsilane, triethoxyvinylsilane, tripropoxyvinylsilane, etc.; dialkoxyalkylvinylsilane, methyldimethoxyvinylsilane, methyldiethoxyvinylsilane, etc.; dialkoxyarylvinylsilane, di(tert-pentoxy)phenylvinylsilane, di(tert-butoxy)phenylvinylsilane, etc.; monoalkoxydialkylvinylsilane, dimethylmethoxyvinylsilane, etc.; monoalkoxydiarylvinylsilane, tert-butoxydiphenylvinylsilane, tert-pentoxydiphenylvinylsilane, etc.; monoalkoxyalkylarylvinylsilane, tert-butoxymethylphenylvinylsilane, tert-butoxyethylphenylvinylsilane, etc.; substituted alkoxyvinylsilane compounds such as tri(β-methoxyethoxy)vinylsilane, etc.

[0067] Among the compounds represented by the above general formula (1), X is preferred. 1 Compounds with single chemical bonds, preferably X 1 It is a chemical single bond, and X 2 X 3 and X 4 Of the two compounds in the mixture that are substituted amino groups, X is particularly preferred. 1 It is a chemical single bond, and X 2 X 3 and X 4 Two of them are dialkylamino compounds.

[0068] 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.

[0069] In addition, examples of vinyl compounds containing functional groups capable of interacting with silicon dioxide, other than those represented by the general formula (1) above, include: 4-N,N-bis(trimethylsilyl)aminostyrene, 3-N,N-bis(trimethylsilyl)aminostyrene, etc.; 4-bis(trimethylsilyl)aminomethylstyrene, 3-bis(trimethylsilyl)aminomethylstyrene, 4-bis(trimethylsilyl)aminoethylstyrene, 3-bis(trimethylsilyl)aminoethylstyrene, etc.

[0070] In addition, when using the compound represented by the above general formula (1) as a vinyl compound containing a functional group capable of interacting with silicon dioxide, that is, introducing the unit represented by the following general formula (3) into the conjugated diene polymer of the present invention as a unit containing a vinyl compound containing a functional group capable of interacting with silicon dioxide.

[0071] [Chemical Formula 2]

[0072]

[0073] In the above general formula (3), X 5 X represents a chemical single bond or a hydrocarbon group. 6 X 7 and X 8 Each can independently represent a hydroxyl group, a substituted amino group, a hydrocarbon oxygen group, or a hydrocarbon group that may have substituents.

[0074] Furthermore, in the unit represented by the above general formula (3), X 5 X in the compound represented by the above general formula (1) 1 Correspondingly, in the unit represented by the above general formula (3), X 6 X 7 and X 8 X in the compound represented by the above general formula (1) 2 X 3 and X 4 Corresponding. Therefore, in the unit represented by the above general formula (3), X 5 X 6 X 7 and X 8 Capable of reacting with X in the compounds represented by the above general formula (1) 1 X 2 X 3 and X 4 Same. Furthermore, when using X 2 X 3 and X 4 When a compound in which at least one of the amino or hydroxyl groups is substituted is represented by the compound of the above general formula (1), X can be hydrolyzed by substituted amino or hydroxyl groups at any step and timing. 2 X 3 and X 4 At least one of them becomes a hydroxyl group.

[0075] The proportion of units containing vinyl compounds with functional groups capable of interacting with silica in the conjugated diene polymer of the present invention is preferably 0 to 10,000% by weight, more preferably 0.001 to 3,000% by weight, and even more preferably 0.002 to 1,000% by weight, based on 100% of the total monomer units. By keeping the proportion of units containing vinyl compounds with functional groups capable of interacting with silica within the above range, the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslinks, and the fuel economy can be further improved in a balanced and favorable manner.

[0076] Furthermore, the conjugated diene polymers of the present invention may contain other monomer units in addition to conjugated diene monomer units, aromatic vinyl monomer units as needed, and monomer units of vinyl compounds containing functional groups capable of interacting with silicon dioxide. Examples of other compounds constituting such 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.

[0077] The bonding of the monomer units in the conjugated diene polymer of the present invention can be of various types, such as block, cone, or random, with random bonding being preferred. By adopting a random bonding pattern, the fuel economy of the resulting rubber crosslinked product can be further improved.

[0078] Furthermore, as the conjugated diene polymer of the present invention, polymers containing modifying groups are preferred, and polymers containing modifying groups (terminal modifying groups) formed by modifying the ends of the polymer chains of the conjugated diene polymer with a modifier are more preferred. In this specification, "conjugated diene polymer containing modifying groups" simply means a polymer in which at least a portion of the polymer chain constituting the conjugated diene polymer contains modifying groups; that is, a portion of the polymer chain constituting the conjugated diene polymer may not contain modifying groups.

[0079] As modifying groups, from the viewpoint of appropriately improving the affinity with fillers such as silica, and further improving the wear resistance and fuel economy of the obtained rubber crosslinked product, modifying groups containing functional groups capable of interacting with silica are preferred. Here, functional groups capable of interacting with silica refer to functional groups that can form covalent bonds with the silica surface, or functional groups that can form intermolecular forces weaker than covalent bonds (e.g., ion-dipole interactions, dipole-dipole interactions, hydrogen bonds, van der Waals forces, etc.). As for the interaction formed between silica and this functional group, covalent bonds and intermolecular forces weaker than covalent bonds (e.g., ion-dipole interactions, dipole-dipole interactions, hydrogen bonds, van der Waals forces, etc.) are preferred. From the viewpoint of easily controlling the ionic strength index within an appropriate range, weak intermolecular forces (e.g., ion-dipole interactions, dipole-dipole interactions, hydrogen bonds, van der Waals forces, etc.) are more preferred. There are no particular limitations on the functional groups that can interact with silicon dioxide; examples include nitrogen-containing functional groups, silicon-containing functional groups, and oxygen-containing functional groups.

[0080] From the viewpoint of high interaction with silica, silicon-containing modifiers having silicon-containing functional groups and nitrogen-containing modifiers having nitrogen-containing functional groups are preferred as modifiers for forming modifying groups, with silicon-containing modifiers being more preferred. Examples of silicon-containing modifiers include siloxane compounds and hydroxyl silane compounds. Examples of nitrogen-containing modifiers include N,N-disubstituted aminoalkyl (methyl)acrylamides such as dimethylaminoethylacrylamide, diethylaminoethylacrylamide, dimethylaminopropylacrylamide, diethylaminopropylacrylamide, dimethylaminobutylacrylamide, diethylaminobutylacrylamide, dimethylaminoethylmethylacrylamide, diethylaminoethylmethylacrylamide, diethylaminopropylmethylacrylamide, diethylaminobutylmethylacrylamide, and diethylaminobutylmethylacrylamide. ; aminoalkoxysilane compounds such as [3-(dimethylamino)propyl]trimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [3-(dimethylamino)propyl]triethoxysilane, [3-(diethylamino)propyl]triethoxysilane, [3-(ethylmethylamino)propyl]trimethoxysilane, and [3-(ethylmethylamino)propyl]triethoxysilane; pyrrolidone compounds such as N-phenyl-2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, and 1-cyclohexyl-2-pyrrolidone.

[0081] As a siloxane compound, any siloxane compound having a siloxane structure (-Si-O-) as the main chain structure is acceptable, and there is no particular limitation. It is preferred to be an organosiloxane having an organic group in the side chain, and more preferably a polyorganosiloxane represented by the following general formula (4).

[0082] [Chemical Formula 3]

[0083]

[0084] In the above general formula (4), R 3 ~R 10 It can be an alkyl group with 1 to 6 carbon atoms, or an aryl group with 6 to 12 carbon atoms; they can be the same or different from each other. X 9 and X 12 It is any group selected from alkyl groups having 1 to 6 carbon atoms, aryl groups having 6 to 12 carbon atoms, alkoxy groups having 1 to 5 carbon atoms, and groups containing an epoxy group having 4 to 12 carbon atoms, which may be the same as or different from each other. X 10 It is an alkoxy group with 1 to 5 carbon atoms, or a group containing an epoxy group with 4 to 12 carbon atoms, when X 10 When multiple X exist, they can be the same or different from each other. 11 A group containing 2 to 20 repeating units of alkylene glycols, when X 11 When multiple integers exist, they can be the same or different from each other. m is an integer from 0 to 200, n is an integer from 0 to 200, k is an integer from 0 to 200, and m+n+k is greater than or equal to 1.

[0085] In the polyorganosiloxanes represented by the above general formula (4), R is the one that can constitute the above general formula (4). 3 ~R 10 X 9 and X 12 Alkyl groups having 1 to 6 carbon atoms include, for example, methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, hexyl, and cyclohexyl. Aryl groups having 6 to 12 carbon atoms include, for example, phenyl and methylphenyl. Among these, methyl and ethyl are preferred from the viewpoint of ease of manufacturing the polyorganosiloxane itself.

[0086] Furthermore, among the polyorganosiloxanes represented by the above general formula (4), as those capable of constituting X 9 X 10 and X 12 Examples of alkoxy groups having 1 to 5 carbon atoms include methoxy, ethoxy, propoxy, isopropoxy, and butoxy. Among these, methoxy and ethoxy are preferred from the viewpoint of ease of manufacturing polyorganosiloxanes themselves.

[0087] Furthermore, among the polyorganosiloxanes represented by the above general formula (4), as those capable of constituting X 9 X 10 and X 12 The group containing an epoxy group and having 4 to 12 carbon atoms can be exemplified by the group represented by the following general formula (5).

[0088] -Z 1 -Z 2 -E 1 (5)

[0089] In the above general formula (5), Z 1 It is an alkylene or alkylarylene group with 1 to 10 carbon atoms, Z 2 E is a methylene, sulfur, or oxygen atom. 1 It is a hydrocarbon group with 2 to 10 carbon atoms that has an epoxy group.

[0090] Z is preferred as the group represented by the above general formula (5). 2 A group consisting of an oxygen atom, more preferably Z. 2 It is an oxygen atom, and E 1 The group is a glycidyl group, and Z is particularly preferred. 1 Alkylene with 1 to 3 carbon atoms, Z 2 It is an oxygen atom, and E 1 It is a glycidyl group.

[0091] Furthermore, in the polyorganosiloxanes represented by the above general formula (4), as X 9 and X 12 Of the above, preferably, the epoxy group is a group having 4 to 12 carbon atoms or an alkyl group having 1 to 6 carbon atoms. Furthermore, as X 10 Of the above, groups containing an epoxy group having 4 to 12 carbon atoms are preferred. Furthermore, X is more preferred. 9 and X 12 X is an alkyl group having 1 to 6 carbon atoms. 10 It is a group containing an epoxy group with 4 to 12 carbon atoms.

[0092] Furthermore, in the polyorganosiloxanes represented by the above general formula (4), as X 11 That is, a group containing 2 to 20 repeating units of alkylene glycols, preferably a group represented by the following general formula (6).

[0093] [Chemical Formula 4]

[0094]

[0095] In the above general formula (6), a is an integer from 2 to 20, X 13It is an alkylene or alkylarylene group with 2 to 10 carbon atoms, R 11 X is a hydrogen atom or a methyl group. 14 It is an alkoxy or aryloxy group having 1 to 10 carbon atoms. Among these, it is preferred that a is an integer from 2 to 8, and X... 13 It is an alkylene group with 3 carbon atoms, R 11 It is a hydrogen atom, and X 14 It is a methoxy group.

[0096] In the polyorganosiloxane represented by the above general formula (4), m is an integer from 0 to 200, preferably an integer from 20 to 150, and more preferably an integer from 30 to 120. When m is 200 or less, the polyorganosiloxane represented by the above general formula (4) becomes easier to manufacture, and its viscosity does not become too high, making operation easier.

[0097] Furthermore, in the polyorganosiloxane represented by the above general formula (4), n is an integer from 0 to 200, preferably an integer from 0 to 150, and more preferably an integer from 0 to 120. k is an integer from 0 to 200, preferably an integer from 0 to 150, and more preferably an integer from 0 to 130. The sum of m, n, and k is 1 or more, preferably 2 to 400, more preferably 20 to 300, and particularly preferably 30 to 250. When the sum of m, n, and k is 1 or more, the reaction between the polyorganosiloxane represented by the above general formula (4) and the active end of the conjugated diene polymer is easily carried out in the manufacturing process of the conjugated diene polymer. Furthermore, when the sum of m, n, and k is 400 or less, the manufacturing of the polyorganosiloxane represented by the above general formula (4) itself becomes easier, and its viscosity does not become too high, and the operation also becomes easier.

[0098] Hydroxyl silane compounds are silicon-containing compounds having at least one hydroxyl group. Preferably, hydroxyl silane compounds are compounds having at least one nitrogen-containing group in addition to having a hydroxyl group; more preferably, compounds having a nitrogen-containing group consisting of a primary amino group having an active hydrogen atom and / or a secondary amino group having an active hydrogen atom.

[0099] There are no particular limitations on such alkyloxysilane compounds, but compounds represented by the following general formula (7) are preferred.

[0100] [Chemical Formula 5]

[0101]

[0102] In the above general formula (7), R 12 A is a hydrocarbon group. 1 A is an alkyl group. 2For groups containing nitrogen atoms, 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.

[0103] In the above general formula (7), R 12 Examples of hydrocarbon groups include alkyl, cycloalkyl, alkenyl, aryl, and aralkyl groups, with alkyl groups having 1 to 6 carbon atoms being preferred. Examples of alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, n-propyl, isopropyl, butyl, pentyl, and hexyl groups, with methyl and ethyl groups being more preferred among these.

[0104] In the above general formula (7), A 1 Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, etc.; olefinic groups include vinyloxy and allyloxy; aryloxy groups include phenoxy and naphthoxy; and arylalkoxy groups include benzyloxy. From a reactivity point of view, alkoxy and aryloxy groups are preferred, alkoxy groups are more preferred, and methoxy and ethoxy groups are particularly preferred.

[0105] In the above general formula (7), A 2 The group is a nitrogen-containing group. There is no particular limitation as long as the group contains a nitrogen atom. Organic groups with nitrogen atoms are preferred. Examples include: 3-aminopropyl, 4-aminobutyl, 3-(2-aminoethylamino)propyl, 2-dimethylaminoethyl, 3-dimethylaminopropyl, 3-diethylaminopropyl, 3-diethylaminopropyl, 3-dipropylaminopropyl, 3-dibutylaminopropyl, 3-phenylmethylaminopropyl, 3-(4-methylpiperazinyl)propyl, N,N-bis(trimethylsilyl)aminopropyl, N,N-bis(triethylsilyl)aminopropyl, N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyl, etc. Among these, from the viewpoint of further improving the low heat generation and wet grip of the obtained rubber crosslinked compound, groups containing primary amino groups and / or secondary amino groups with active hydrogen atoms, such as 3-aminopropyl, 4-aminobutyl, and 3-(2-aminoethylamino)propyl, are preferred. Furthermore, "active hydrogen atom" refers to a hydrogen atom bonded to an atom other than a carbon atom, and preferably has a lower bond energy than the carbon-hydrogen bond of the polymethylene chain.

[0106] In the compound represented by the above general formula (7), 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. From the viewpoint of reactivity with polymer chains having active ends and reaction residues generated by the reaction of polymer chains having active ends with siloxane compounds, it is preferable that p is an integer from 0 to 1, q is an integer from 2 to 3, and r is an integer from 1 to 2, and more preferably p=0, q=3, and r=1. In addition, when p is 2, the two R residues contained in one molecule of the compound represented by general formula (7) 12 The groups represented can be the same group or different groups. Similarly, when q is 2 or 3, the multiple A groups contained in one molecule of the compound represented by general formula (7) 1 The groups represented can be the same group or different groups. When r is 2 or 3, the compound represented by one molecule of general formula (7) contains multiple A groups. 2 The groups represented can be the same group or different groups.

[0107] As a specific example of the compound represented by the above general formula (7), there is no particular limitation. For example, A in general formula (7) 2 Compounds containing a primary amino group with an active hydrogen atom and / or a secondary amino group with an active hydrogen atom include: 3-aminopropyldimethylmethoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyldimethylethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, etc., having 3-aminopropyl as an A group. 2 Compounds such as 4-aminobutyldimethylmethoxysilane, 4-aminobutylmethyldimethoxysilane, 4-aminobutyltrimethoxysilane, 4-aminobutyldimethylethoxysilane, 4-aminobutylmethyldiethoxysilane, and 4-aminobutyltriethoxysilane, etc., which contain 4-aminobutyl as an A group. 2 Compounds such as 3-(2-aminoethylamino)propyl dimethylmethoxysilane, 3-(2-aminoethylamino)propyl methyl dimethoxysilane, 3-(2-aminoethylamino)propyl trimethoxysilane, 3-(2-aminoethylamino)propyl dimethyl ethoxysilane, 3-(2-aminoethylamino)propyl methyl diethoxysilane, and 3-(2-aminoethylamino)propyl triethoxysilane, etc., containing 3-(2-aminoethylamino)propyl as A 2 Compounds, etc. Among these, those having a 3-(2-aminoethylamino)propyl group as A are preferred. 2 The compound, more preferably 3-(2-aminoethylamino)propyltrimethoxysilane.

[0108] Furthermore, examples of compounds in which A2 in general formula (7) is a group other than a primary amino group containing an active hydrogen atom and / or a secondary amino group containing an active hydrogen atom include: 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-dimethylaminopropyldimethylmethoxysilane, 3-dimethylaminopropyltriethoxysilane, 3-dimethylaminopropylmethyldiethoxysilane, 3-dimethylaminopropyldimethylethoxysilane, etc., having 3-dimethylaminopropyl as A 2 Compounds such as [3-(diethylamino)propyl]trimethoxysilane, 3-diethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyldimethylmethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-diethylaminopropylmethyldiethoxysilane, and 3-diethylaminopropyldimethylethoxysilane, etc., containing 3-diethylaminopropyl as an A group. 2 Compounds such as 3-dipropylaminopropyltrimethoxysilane, 3-dipropylaminopropylmethyldimethoxysilane, 3-dipropylaminopropyldimethylmethoxysilane, 3-dipropylaminopropyltriethoxysilane, 3-dipropylaminopropylmethyldiethoxysilane, and 3-dipropylaminopropyldimethylethoxysilane, etc., which contain 3-dipropylaminopropyl as an A group, are mentioned. 2 Compounds such as 3-dibutylaminopropyltrimethoxysilane, 3-dibutylaminopropylmethyldimethoxysilane, 3-dibutylaminopropyldimethylmethoxysilane, 3-dibutylaminopropyltriethoxysilane, 3-dibutylaminopropylmethyldiethoxysilane, and 3-dibutylaminopropyldimethylethoxysilane, etc., which contain 3-dibutylaminopropyl as an A group. 2 Compounds such as 3-phenylmethylaminopropyltrimethoxysilane, 3-phenylmethylaminopropylmethyldimethoxysilane, 3-phenylmethylaminopropyldimethylmethoxysilane, 3-phenylmethylaminopropyltriethoxysilane, 3-phenylmethylaminopropylmethyldiethoxysilane, and 3-phenylmethylaminopropyldimethylethoxysilane contain 3-phenylmethylaminopropyl as an A group. 2 Compounds 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, etc., have 3-(4-methylpiperazinyl)propyl as A 2 Compounds;

[0109] N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, and N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, etc., contain N,N-bis(trimethylsilyl)aminopropyl as an A 2 Compounds; N,N-bis(triethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(triethylsilyl)aminopropylmethyldiethoxysilane, etc., having N,N-bis(triethylsilyl)aminopropyl as A 2 Compounds 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, etc., having N,N',N'-tris(trimethylsilyl)-N-(2-aminoethyl)-3-aminopropyl as A 2 Compounds, etc. Among these, those having 3-dimethylaminopropyl as A are preferred. 2 The compound, more preferably 3-dimethylaminopropyltrimethoxysilane.

[0110] Furthermore, as a hydroxyl silane compound, the compound represented by the following general formula (8) is preferred.

[0111] [Chemical Formula 6]

[0112]

[0113] In the above general formula (8), A 3 R is an alkyl group. 13 R represents a hydrocarbon group that can have substituents. 14 and R 15 Each can independently represent a hydrocarbon group that may have substituents, R 14 and R 15 They can also bond to each other and form ring structures with the nitrogen atoms they bond to. In the case of forming such a ring structure, in addition to the nitrogen atoms they bond to, they can also form ring structures with heteroatoms other than the nitrogen atoms they bond to. s is an integer from 0 to 2.

[0114] In the above general formula (8), A3 Examples of alkoxy groups include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, etc.; olefinic groups include vinyloxy and allyloxy; aryloxy groups include phenoxy and naphthoxy; and arylalkoxy groups include benzyloxy. From a reactivity point of view, alkoxy and aryloxy groups are preferred, alkoxy groups are more preferred, and methoxy and ethoxy groups are particularly preferred.

[0115] In the above general formula (8), s (that is, A in general formula (8) 3 The number of groups represented is an integer from 0 to 2, and s is preferably 2. When s in general formula (8) is 2, the two A groups contained in one molecule of the compound represented by general formula (8) 3 The groups represented can be the same group or different groups.

[0116] In the above general formula (8), R 13 This indicates a hydrocarbon group that can have substituents. As a group capable of being R... 13 The hydrocarbon group is not particularly limited, and examples include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; alkenyl groups such as vinyl and allyl; alkynyl groups such as ethynyl and propynyl; aryl groups such as phenyl and naphthyl; and aralkyl groups such as benzyl. Among these, alkyl and aryl groups are preferred, alkyl groups are more preferred, and methyl and ethyl groups are particularly preferred. Furthermore, R 13 The hydrocarbon group represented may have substituents other than hydrocarbon groups. There are no particular limitations on the substituents, but examples include: carboxyl groups, acid anhydride groups, hydrocarbon carbonyl groups, alkoxy carbonyl groups, acyloxy groups, etc., containing carbonyl groups; epoxy groups, oxygen groups, cyano groups, amino groups, halogen groups, etc. Furthermore, when s in general formula (8) is 0, the two R groups contained in one molecule of the compound represented by general formula (8) 13 The groups represented can be the same group or different groups.

[0117] In the above general formula (8), R 14 and R 15 Each can independently represent a hydrocarbon group that may have substituents, R 14 and R 15 They can also bond to each other to form ring structures, and together with the nitrogen atoms they are bonded to, form ring structures. Furthermore, in the case of ring structures, they can form ring structures with heteroatoms other than the nitrogen atoms they are bonded to. In R 14 and R 15 In the absence of mutual bonding, as a form that can be R 14 and R 15The hydrocarbon group is not particularly limited, and examples include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; alkenyl groups such as vinyl and allyl; alkynyl groups such as ethynyl and propynyl; aryl groups such as phenyl and naphthyl; and aralkyl groups such as benzyl. Among these, alkyl and aryl groups are preferred, alkyl groups are more preferred, and methyl and ethyl groups are particularly preferred. Furthermore, in R... 14 and R 15 When the nitrogen atoms bonded to each other and together with them form a ring structure, as R 14 and R 15 The divalent hydrocarbon groups formed by bonding are not particularly limited, but can be exemplified by: n-butylidene (in general formula (8), where the nitrogen atoms bonded to them together form 1-pyrrolidinyl), n-penteneidene (in the case of forming 1-piperidinyl), etc.; butylidenedienyl (in the case of forming 1-pyrrolidinyl), etc.

[0118] Additionally, in R 14 and R 15 When the nitrogen atoms bonded to each other and together form a ring structure, a 4- to 8-membered ring structure is preferred as the ring structure.

[0119] In addition, R 14 and R 15 The hydrocarbon group represented, regardless of whether it forms a ring structure, can have substituents other than the hydrocarbon group. There are no particular limitations on these substituents, and examples include: carboxyl groups, acid anhydride groups, hydrocarbon carbonyl groups, alkoxy carbonyl groups, acyloxy groups, and other carbonyl-containing groups; epoxy groups, oxygen groups, cyano groups, amino groups, halogen groups, etc. Furthermore, in R... 14 and R 15 When nitrogen atoms bonded to each other and together with them form a ring structure, the atoms forming the ring structure may include carbon atoms and heteroatoms other than the nitrogen atoms to which they are bonded. Examples of such heteroatoms include nitrogen atoms and oxygen atoms.

[0120] As a compound represented by the above general formula (8), R is a particularly preferred compound. 14 and R 15 The compounds represented by the hydrocarbon groups are bonded to each other, and together with the nitrogen atoms bonded to them, form a piperazine ring structure. More specifically, compounds represented by the following general formula (9) are particularly preferred. By using compounds having such a structure as those represented by general formula (8), the fuel economy of the obtained rubber crosslinks can be further improved.

[0121] [Chemical Formula 7]

[0122]

[0123] In the above general formula (9), A 3 R13 Both and s represent A in the above general formula (8). 3 R 13 The same content as s, R 16 It indicates a hydrocarbon group.

[0124] In the above general formula (9), R 16 Indicates a hydrocarbon group. As it can be R... 16 The hydrocarbon group is not particularly limited, and examples include: alkyl groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, and tert-butyl; alkenyl groups such as vinyl and allyl; alkynyl groups such as ethynyl and propynyl; aryl groups such as phenyl and naphthyl; and aralkyl groups such as benzyl. Among these, alkyl and aryl groups are preferred, alkyl groups are more preferred, and methyl groups are particularly preferred.

[0125] Specific examples of compounds represented by the above general formula (8) include: 2,2-dimethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silazine octane, 2,2-diethoxy-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silazine octane, 2,2-dimethoxy-8-(N,N-diethylamino)methyl-1,6-dioxa-2-silazine octane, 2-methoxy-2-methyl-8-(4-methylpiperazinyl)methyl-1,6-dioxa-2-silazine octane, etc. These compounds represented by general formula (8) can be used alone or in combination of two or more.

[0126] From the viewpoint of achieving a good balance in further improving the processability of conjugated diene polymers, the abrasion resistance of the resulting rubber crosslinks, and fuel economy, compounds represented by the above general formula (7) are preferred among alkyloxysilane compounds, and A in the above general formula (7) is more preferred. 2 The compound is a compound containing a primary amino group having an active hydrogen atom and / or a secondary amino group having an active hydrogen atom, and more preferably A in the above general formula (7). 2 It is a compound containing both a primary amino group with an active hydrogen atom and a secondary amino group with an active hydrogen atom.

[0127] In the conjugated diene polymer of the present invention, the silicon content is 95 ppm by weight or more. When the silicon content of the conjugated diene polymer is less than 95 ppm by weight, it is difficult to achieve a good balance in improving the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslinked product, and the fuel economy.

[0128] In the conjugated diene polymer of the present invention, the silicon content is not particularly limited as long as it is 95 ppm by weight or more. Preferably, the silicon content is 120 ppm by weight or more, more preferably 150 ppm by weight or more, further preferably 200 ppm by weight or more, and particularly preferably 250 ppm by weight or more. By keeping the silicon content within the above range, the interaction between the conjugated diene polymer and fillers such as silica can be further improved, and the dispersibility of fillers such as silica can be further improved. As a result, the processability of the conjugated diene polymer, the abrasion resistance of the obtained rubber crosslinked product, and the fuel economy can be further improved in a balanced manner.

[0129] On the other hand, a moderately low silicon content implies a moderately high molecular weight of the conjugated diene polymer relative to the silicon content. Furthermore, with a moderately high molecular weight of the conjugated diene polymer, entanglement between the polymer chains tends to occur more effectively, resulting in a tendency for further improvement in the abrasion resistance of the obtained rubber crosslinked product. Therefore, the silicon content is preferably 3000 ppm by weight or less, more preferably 2000 ppm by weight or less, and even more preferably 1000 ppm by weight or less.

[0130] Methods for controlling silicon content include, for example, controlling the content of units in conjugated diene polymers containing vinyl compounds with functional groups capable of interacting with silicon dioxide; and controlling the type and amount of silicon-containing modifiers used.

[0131] Silicon content can be determined by X-ray fluorescence analysis or alkali fusion-inductively coupled plasma atomic emission spectrometry (ICPAES). X-ray fluorescence analysis is preferred. However, in cases where conjugated diene polymers contain impurities, the measured silicon content may sometimes be inaccurate. In such cases, the conjugated diene polymer can be subjected to Soxhlet extraction or similar methods to remove impurities before determining the silicon content.

[0132] The ionic strength index of the conjugated diene polymer of the present invention is below 75%.

[0133] In this specification, the ionic strength index refers to the value calculated according to the following formula (I) based on the results of gel permeation chromatography (GPC) determination using a styrene column (hereinafter sometimes referred to as "GPC determination") and GPC determination using a cation exchange column for a sample solution containing a conjugated diene polymer and an internal standard polystyrene (molecular weight 5000).

[0134] Ionic strength index (%) = {1 - (A)} CX / B CX )×(B sty / A sty)}×100 (I)

[0135] A CX Peak area of ​​molecular weight distribution curves of conjugated diene polymers determined by GPC using a cation exchange column.

[0136] B CX Peak area of ​​internal standard polystyrene determined by GPC using a cation exchange column.

[0137] B sty Peak area of ​​internal standard polystyrene determined by GPC using a styrene-based column.

[0138] A sty Peak areas of molecular weight distribution curves of conjugated diene polymers determined by GPC using a styrene-based column.

[0139] Here, A CX and A sty The peak area of ​​the molecular weight distribution curve of conjugated diene polymers in the definition refers to the peak area of ​​the molecular weight distribution curve obtained by removing the region with a molecular weight of less than 5000 and further removing the peak of the internal standard polystyrene.

[0140] In addition, columns using styrene-divinylbenzene-based gel fillers are defined as styrene-based columns.

[0141] In addition, GPC determinations using styrene-based columns and GPC determinations using cation exchange columns can be performed under the conditions described in the examples described later.

[0142] Furthermore, the measurement of the ionic strength index may be inaccurate when conjugated diene polymers contain impurities such as oil. In such cases, the conjugated diene polymer can be subjected to Soxhlet extraction or other methods to remove impurities before measuring the ionic strength index.

[0143] In GPC measurements using cation exchange columns, some polymer chains in conjugated diene polymers undergo ionic interactions with the surface of the cation exchange column. Therefore, the greater the proportion of ionicly interacting polymer chains in the conjugated diene polymer, and the stronger the ionic interaction of these polymer chains, the lower the peak intensity of the molecular weight distribution curve obtained using a cation exchange column compared to that obtained using a styrene column, and the larger the ionic intensity index calculated from equation (I) above.

[0144] When the ionic strength index of a conjugated diene polymer is greater than 75%, the polymer chains tend to over-aggregate, resulting in insufficient chain entanglement. Consequently, it becomes difficult to achieve a balanced improvement in the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslinked product, and fuel economy. In particular, when the ionic strength index of the conjugated diene polymer is greater than 75%, the abrasion resistance of the resulting rubber crosslinked product tends to decrease.

[0145] The lower limit of the ionic strength index is only required to be 0% or higher, without particular limitation, but preferably 0.5% or higher. When the ionic strength index is within the above range, the interaction between the polymer chains of the conjugated diene polymer is appropriately generated, and the entanglement of the polymer chains is generated more effectively. As a result, the wear resistance of the obtained rubber crosslinked product can be further improved.

[0146] Especially when the processability of conjugated diene polymers is required, there is a tendency to further improve the processability of conjugated diene polymers by setting the upper limit of the ionic strength index to preferably 60% or less, more preferably 45% or less, even more preferably 30% or less, even more preferably 20% or less, particularly preferably 10% or less, and most preferably 5% or less.

[0147] Furthermore, especially when the wear resistance and fuel economy of the obtained rubber crosslinked material are required, there is a tendency to further improve the wear resistance and fuel economy of the obtained rubber crosslinked material by making the lower limit of the ionic strength index more preferably 0.8% or more, more preferably 2% or more, more preferably 3.5% or more, even more preferably 9% or more, particularly preferably 20% or more, and most preferably 30% or more.

[0148] The ionic strength index can be controlled by adjusting the proportion of polymer chains in conjugated diene polymers that have functional groups (e.g., cationic groups such as amino groups) that interact with cation exchange columns, the position of the functional group in the polymer chain (e.g., in the polymer chain or at the end of the polymer chain), the molecular structure near the functional group, and the proportion of the functional group, and preferably by appropriately combining them.

[0149] The weight-average molecular weight (Mw) of the conjugated diene polymer of the present invention is preferably 200,000 or more. The higher the weight-average molecular weight (Mw), the easier it is for the polymer chains of the conjugated diene polymer to entangle, thus tending to further improve the abrasion resistance of the resulting rubber crosslinked product. Furthermore, the weight-average molecular weight (Mw) of the conjugated diene polymer of the present invention is preferably 10 million or less. By appropriately reducing the weight-average molecular weight (Mw), the viscosity of the conjugated diene polymer during processing is appropriately reduced, tending to further improve the processability of the conjugated diene polymer. Therefore, the weight-average molecular weight (Mw) is preferably in the range of 200,000 to 10 million, more preferably in the range of 350,000 to 5 million, even more preferably in the range of 400,000 to 5 million, even more preferably in the range of 500,000 to 3 million, even more preferably in the range of 500,000 to 2 million, particularly preferably in the range of 500,000 to 1.5 million, and most preferably in the range of 550,000 to 1.2 million.

[0150] The molecular weight distribution (Mw / Mn) of the conjugated diene polymer of the present invention is preferably 1.5 or higher. A higher Mw / Mn ratio tends to further improve the processability of the conjugated diene polymer and the abrasion resistance of the resulting rubber crosslinked product. A molecular weight distribution (Mw / Mn) of 1.5 to 5 is more preferred, even more preferred is 1.5 to 3, and particularly preferred is 1.55 to 3.

[0151] In the conjugated diene polymer of the present invention, it is preferable that the number of peaks in the molecular weight distribution curve is 2 or more. A higher number of peaks in the molecular weight distribution curve tends to result in a wider molecular weight distribution, thus the polymer chains of the conjugated diene polymer tend to entangle more easily, leading to further improved wear resistance of the resulting rubber crosslinked product. The number of peaks in the molecular weight distribution curve is more preferably in the range of 2 to 6, and even more preferably in the range of 3 to 5. Methods for ensuring that the number of peaks in the molecular weight distribution curve is 2 or more can be exemplified by, for example, adding a polymerization initiator during the polymerization process when synthesizing the conjugated diene polymer by monomer polymerization, and continuing polymerization; performing a coupling reaction on the polymer chains obtained by polymerization; or mixing two or more conjugated diene polymers with different molecular weight distribution curves, preferably in a polymer solution state, etc. These methods can also be used in combination.

[0152] In this specification, when the number of peaks in the molecular weight distribution curve is two or more, the peak with the lowest molecular weight is defined as the first peak, and after the first peak, peaks are sequentially defined from the lowest molecular weight side as the second peak, the third peak, and so on. Furthermore, the molecular weight at which the molecular weight distribution curve shows a maximum value for each peak is defined as the peak molecular weight of that peak.

[0153] In the conjugated diene polymer of the present invention, for example, when the number of peaks in the molecular weight distribution curve is 3, the molecular weight at the peak of the first peak is preferably in the range of 80,000 to 1,500,000, more preferably in the range of 90,000 to 1,200,000, and even more preferably in the range of 100,000 to 800,000. Furthermore, the molecular weight at the peak of the second peak is preferably in the range of 150,000 to 5,000,000, more preferably in the range of 170,000 to 4,000,000, and even more preferably in the range of 200,000 to 3,000,000. The molecular weight at the peak of the third peak is preferably in the range of 200,000 to 5,000,000, more preferably in the range of 220,000 to 4,000,000, and even more preferably in the range of 250,000 to 3,000,000.

[0154] In the conjugated diene polymer of the present invention, for example, when the number of peaks in the molecular weight distribution curve is four, the molecular weight at the peak of the first peak is preferably in the range of 80,000 to 1,500,000, more preferably in the range of 90,000 to 1,200,000, and even more preferably in the range of 100,000 to 800,000. Furthermore, the molecular weight at the peak of the second peak is preferably in the range of 150,000 to 5,000,000, more preferably in the range of 170,000 to 4,000,000, and even more preferably in the range of 200,000 to 3,000,000. The molecular weight at the peak of the third peak is preferably in the range of 200,000 to 5,000,000, more preferably in the range of 220,000 to 4,000,000, and even more preferably in the range of 250,000 to 3,000,000. The molecular weight at the peak of the fourth peak is preferably in the range of 300,000 to 5,000,000, and even more preferably in the range of 400,000 to 4,000,000.

[0155] In the conjugated diene polymer of the present invention, for example, when the number of peaks in the molecular weight distribution curve is 5, the molecular weight at the peak of the first peak is preferably in the range of 80,000 to 1,500,000, more preferably in the range of 90,000 to 1,200,000, and even more preferably in the range of 100,000 to 800,000. Furthermore, the molecular weight at the peak of the second peak is preferably in the range of 150,000 to 5,000,000, more preferably in the range of 170,000 to 4,000,000, and even more preferably in the range of 200,000 to 3,000,000. The molecular weight at the peak of the third peak is preferably in the range of 200,000 to 5,000,000, more preferably in the range of 220,000 to 4,000,000, and even more preferably in the range of 250,000 to 3,000,000. The molecular weight at the peak of the fourth peak is preferably in the range of 300,000 to 5,000,000, more preferably in the range of 400,000 to 4,000,000, and even more preferably in the range of 500,000 to 3,000,000. The molecular weight at the peak of the fifth peak is preferably in the range of 400,000 to 5,000,000, more preferably in the range of 500,000 to 4,000,000, and even more preferably in the range of 600,000 to 3,000,000.

[0156] The weight-average molecular weight (Mw), molecular weight distribution (Mw / Mn), number of peaks in the molecular weight distribution curve, and peak-top molecular weight of each peak can be determined by the following method. First, for a sample solution containing a conjugated diene polymer and an internal standard polystyrene, GPC analysis using a styrene-based column is performed in the same manner as the determination of the ionic strength index described above to obtain the molecular weight distribution curve of the conjugated diene polymer. Based on the obtained molecular weight distribution curve of the conjugated diene polymer, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) converted from polystyrene can be calculated. Furthermore, the obtained molecular weight distribution curve of the conjugated diene polymer is divided into regions with one maximum value sandwiched between the baseline or the minimum value. The peak area of ​​each divided region is calculated. When the peak area of ​​the entire molecular weight distribution curve of the conjugated diene polymer is set to 100%, the number of regions with a peak area of ​​1% or more can be used as the number of molecular weight peaks. Furthermore, for each segmented region (limited to regions with a peak area of ​​more than 1%), the peak of the region with the lowest molecular weight is taken as the first peak. After the first peak, the regions with the lowest molecular weight are successively defined as the second peak, the third peak, and so on. Based on this, the peak molecular weight of each peak (the molecular weight of the region showing the maximum value) can be calculated.

[0157] As the conjugated diene polymer of the present invention, polymers with a Mooney viscosity (ML1+4) of 10 or more and 200 or less are preferred, more preferably polymers with a value of 20 or more and 150 or less, even more preferably polymers with a value of 30 or more and 145 or less, particularly preferably polymers with a value of 40 or more and 140 or less, and most preferably polymers with a value of 50 or more and 135 or less. When the Mooney viscosity is within the above range, the processability becomes better. The Mooney viscosity (ML1+4) is measured at 100°C according to JIS K6300-1:2013.

[0158] Furthermore, from an operational point of view, the conjugated diene polymer of the present invention can preferably be used in a state of being mixed with the extender oil described later. When the conjugated diene polymer is used in a state of being mixed with the extender oil, the Mooney viscosity (ML1+4) of the conjugated diene polymer mixed with the extender oil can be determined as the Mooney viscosity (ML1+4) of the conjugated diene polymer. The preferred range and measurement conditions of the Mooney viscosity (ML1+4) in this case are the same as those described above.

[0159] <Methods for manufacturing conjugated diene polymers>

[0160] The conjugated diene polymers of the present invention can be obtained, for example, by polymerizing a monomer mixture containing at least a conjugated diene monomer using a polymerization initiator in an inert solvent. The conjugated diene polymers of the present invention are preferably polymerized by solution polymerization.

[0161] The conjugated diene monomer included in the monomer mixture can be the same conjugated diene monomer exemplified above as a conjugated diene monomer capable of constituting conjugated diene polymers. Furthermore, as needed, the monomer mixture may include the aforementioned aromatic vinyl monomers, vinyl compounds containing functional groups capable of interacting with silicon dioxide, and other monomers.

[0162] The inactive solvent used in polymerization is a commonly used in solution polymerization, and there are no particular limitations as long as it does not hinder the polymerization reaction. Specific examples of inactive solvents include: chain 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 inactive solvents can be used alone or in combination of two or more. The amount of inactive solvent used is such that the monomer concentration is, for example, 1 to 50% by weight, preferably 10 to 40% by weight.

[0163] Furthermore, the polymerization initiator used in the polymerization is not particularly limited as long as it is a polymerization initiator capable of polymerizing a mixture of monomers containing conjugated diene monomers. Specific examples include polymerization initiators with organoalkali metal compounds, organoalkaline earth metal compounds, and lanthanide metal compounds as the main catalyst. Examples of organoalkali metal compounds include organolithium compounds, organosodium compounds, and organopotassium compounds. Specifically, examples include: organomonal lithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, and stilbene lithium; organopolylithium compounds such as dilithium methane, 1,4-dilithium butane, 1,4-dilithium-2-ethylcyclohexane, 1,3,5-trilithiumbenzene, and 1,3,5-tris(lithium methyl)benzene; organosodium compounds such as sodium naphthalene; and organopotassium compounds such as potassium naphthalene. In addition, examples of organoalkaline earth metal compounds include di-n-butylmagnesium, di-n-hexylmagnesium, calcium diethoxy, calcium distearate, di-tert-butoxystrontium, barium diethoxy, barium diisopropoxy, barium diethylmercapto, barium di-tert-butoxy, barium diphenoxy, barium diethylamino, barium distearate, and barium dicarbonyl. Examples of polymerization initiators using lanthanide metal compounds as the main catalyst include: polymerization initiators using lanthanide metal salts formed by lanthanide metals such as lanthanum, cerium, praseodymium, neodymium, samarium, and gadolinium with carboxylic acids and phosphorus-containing organic acids as the main catalyst, and using the main catalyst and co-catalysts such as alkyl aluminum compounds, organoaluminum hydride compounds, and organoaluminum halide compounds. Among these polymerization initiators, organolithium monolithic compounds and organolithium multi-component compounds are preferred, organolithium monolithic compounds are more preferred, and n-butyllithium is particularly preferred. In addition, organoalkali metal compounds can be pre-reacted 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 exhibit superior fuel economy and abrasion resistance. These polymerization initiators can be used alone or in combination of two or more.

[0164] Examples of organoalkali metal amide compounds include compounds formed by reacting a secondary amine compound with an organoalkali metal compound, among which compounds represented by the following general formula (10) are preferred.

[0165] R 17 -N(-R 18 )-M 1 (10)

[0166] In general formula (10), M 1 R represents an alkali metal atom. 17 R 18Each independently represents a protecting group of alkyl, cycloalkyl, aryl, aralkyl, or amino groups, or a group capable of hydrolyzing to produce a hydroxyl group, R 17 and R 18 They can also bond to each other and form ring structures with the nitrogen atoms they bond to. In the case of forming such ring structures, in addition to the nitrogen atoms they bond to, they can also form ring structures with heteroatoms other than the nitrogen atoms they bond to.

[0167] The alkyl group is not particularly limited, but alkyl groups with 1 to 20 carbon atoms are preferred, and alkyl groups with 1 to 10 carbon atoms are more preferred. Examples of such alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, and n-decyl.

[0168] The cycloalkyl group is not particularly limited, but it is preferred to be a cycloalkyl group with 3 to 20 carbon atoms, and more preferably a cycloalkyl group with 3 to 12 carbon atoms. Examples of such cycloalkyl groups include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and cyclododecyl.

[0169] There is no particular limitation on the aryl group, but aryl groups with 6 to 12 carbon atoms are preferred, and aryl groups with 6 to 10 carbon atoms are more preferred. Examples of such aryl groups include phenyl, 1-naphthyl, and 2-naphthyl.

[0170] There is no particular limitation on the aralkyl group, but aralkyl groups with 7 to 13 carbon atoms are preferred, and aralkyl groups with 7 to 9 carbon atoms are more preferred. Examples of such aralkyl groups include benzyl and phenethyl.

[0171] There are no particular limitations on the protecting group of the amino group; any group that functions as a protecting group of the amino group is acceptable. Examples of such alkylsilyl groups include: trimethylsilyl, triethylsilyl, triphenylsilyl, methyldiphenylsilyl, ethylmethylphenylsilyl, tert-butyldimethylsilyl, etc.

[0172] Additionally, in R 17 and / or R 18 In the case where the protecting group is an amino group, the R in general formula (12) can be introduced into one end of the polymer chain of the resulting conjugated diene polymer by removing the protecting group from the amino group. 19 and / or R 20 It represents the structure of a hydrogen atom.

[0173] There is no particular limitation on the group that can be hydrolyzed to produce a hydroxyl group. For example, any group that produces a hydroxyl group by hydrolysis in the presence of an acid or the like can be used. Examples include alkoxyalkyl groups and groups containing epoxy groups.

[0174] Examples of alkoxyalkyl groups include: methoxymethyl, ethoxymethyl, ethoxyethyl, propoxymethyl, butoxymethyl, butoxyethyl, propoxyethyl, etc.

[0175] In addition, examples of groups containing epoxy groups include those represented by the following general formula (11).

[0176] -Z 3 -Z 4 -E 2 (11)

[0177] In general formula (11), Z 3 Z is an alkylene or alkylarylene group having 1 to 10 carbon atoms. 4 E is a methylene, sulfur, or oxygen atom. 2 It is a glycidyl group.

[0178] In addition, R 17 and R 18 They can also bond to each other, and the nitrogen atoms bonded to them together form a ring structure, as in this case, R 17 and R 18 Specific examples of structures formed by nitrogen atoms bonded to them include the nitrogen heterocyclic butane ring (R... 17 and R 18 (Propylene), pyrrolidine ring (R) 17 and R 18 (Butylene), piperidine ring (R) 17 and R 18 (amylene), hexamethyleneimine ring (R) 17 and R 18 For example, (as in Aztec). In R 17 and R 18 When the nitrogen atoms bonded to each other and together form a ring structure, the ring structure is preferably a 4- to 8-membered ring structure.

[0179] Furthermore, in general formula (10), M 1 The atom is an alkali metal atom. Examples of such alkali metal atoms include lithium, sodium, and potassium atoms. Among these, lithium atoms are preferred from the viewpoint of polymerization activity.

[0180] When the compound represented by the above general formula (10) is used as a polymerization initiator, the amine structure of the organoalkali metal amide compound remains bonded to the polymerization initiation end of the polymer chain. Therefore, when the compound represented by the above general formula (10) is used as a polymerization initiator, the structure represented by the following general formula (12) is introduced at one end of the polymer chain of the resulting conjugated diene polymer.

[0181] R 19 -N(-R 20 )- (12)

[0182] In general formula (12), R 19 R 20 Each independently represents a hydrogen atom, alkyl, cycloalkyl, aryl, aralkyl, amino protecting group, or a group capable of hydrolyzing to produce a hydroxyl group, R 19 and R 20 They can also bond to each other and form ring structures with the nitrogen atoms they bond to. In the case of forming such ring structures, in addition to the nitrogen atoms they bond to, they can also form ring structures with heteroatoms other than the nitrogen atoms they bond to.

[0183] As someone who can become R 19 R 20 The alkyl, cycloalkyl, aryl, aralkyl, amino protecting groups or groups that can be hydrolyzed to produce hydroxyl groups, can be listed as R in general formula (10). 17 R 18 The same group, in addition, in R 19 and R 20 When the nitrogen atoms bonded to each other and together with them form a ring structure, it is also possible to form a ring structure with R in general formula (10). 17 R 18 Same group. Additionally, it can become R. 19 R 20 The hydrogen atom is introduced through the detachment of the protecting group of the amino group.

[0184] There are no particular limitations on the method for adding the organoalkali metal amide compound, which acts as a polymerization initiator, to the polymerization system. The following methods can be used: reacting a secondary amine compound with the organoalkali metal compound beforehand to obtain the organoalkali metal amide compound, mixing it with a monomer containing a conjugated diene monomer, and then carrying out the polymerization reaction. Alternatively, the following methods can be used: adding the organoalkali metal compound and the secondary amine compound separately to the polymerization system, mixing them with a monomer containing a conjugated diene monomer, thereby generating the organoalkali metal amide compound in the polymerization system, and then carrying out the polymerization reaction. Reaction conditions such as reaction temperature are not particularly limited; for example, the desired polymerization reaction conditions can be followed.

[0185] The amount of secondary amine compound used can be determined based on the amount of polymerization initiator to be targeted, and is typically 0.01 to 1.5 mmol, preferably 0.1 to 1.2 mmol, and more preferably 0.5 to 1.0 mmol per 1 mmol of organoalkali metal compound.

[0186] The amount of polymerization initiator used can be determined based on the molecular weight distribution curve of the target conjugated diene polymer, and is typically 1 to 50 mmol per 1000g of monomer, preferably 1.5 to 20 mmol, and more preferably 2 to 15 mmol.

[0187] After polymerization is initiated using a polymerization initiator, further polymerization initiation can be performed by adding the polymerization initiator to the polymerization system to continue polymerization. There are no particular limitations on the timing or number of times the polymerization initiator is added; it can be determined based on the molecular weight distribution curve of the target conjugated diene polymer. There is no particular limitation on the amount of polymerization initiator used in each addition operation; preferably 0.1 to 0.7 moles, more preferably 0.2 to 0.6 moles, relative to 1 mole of polymerization initiator used during polymerization initiation.

[0188] 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. As for the polymerization method, either batch or continuous polymerization can be used. From the perspective of easily controlling the randomness of the bonding between the conjugated diene monomer unit and the aromatic vinyl monomer unit, batch polymerization is preferred.

[0189] Furthermore, when polymerizing a monomer mixture containing conjugated diene monomers, it is preferable to add a polar compound to an inactive organic solvent in order to adjust the vinyl bond content in the conjugated diene monomer units of the resulting conjugated diene polymer. Examples of polar compounds include ether compounds such as ethylene glycol diethyl ether, ethylene glycol dibutyl ether, dibutyl ether, and tetrahydrofuran; tertiary amines such as tetramethylethylenediamine; alkali metal alkoxides; and phosphine compounds. Among these, ether compounds and tertiary amines are preferred, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, and tertiary amines are more preferred, tertiary amines are even more preferred, and tetramethylethylenediamine is particularly preferred. These polar compounds can be used alone or in combination of two or more. The amount of polar compound used is determined according to the target vinyl bond content, and is preferably 0.001 to 100 moles relative to 1 mole of polymerization initiator, more preferably 0.01 to 10 moles. 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 it is difficult to produce abnormalities due to the deactivation of the polymerization initiator.

[0190] The conjugated diene polymer of the present invention can also be obtained by a manufacturing method having the following steps: in an inactive solvent, a monomer (a) containing isoprene is polymerized by a polymerization initiator to form a polymer block (A) with active ends; the polymer block (A) with active ends is mixed with a monomer (b) containing 1,3-butadiene, and the polymerization reaction is continued to have polymer blocks (A) and polymer blocks (B).

[0191] By employing such a manufacturing method, conjugated diene polymers can be made into polymer blocks containing polymer blocks (A) comprising isoprene monomer units and polymer blocks (B) comprising 1,3-butadiene monomer units linked together. As a result, the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslinks, and fuel economy can be further improved in a balanced manner.

[0192] As the monomer (a) used to form the polymer block (A), any monomer containing isoprene is acceptable; the monomer used should correspond to the monomer composition of the polymer block (A) to be formed. For example, if the polymer block (A) is a polymer block composed of isoprene monomer units and aromatic vinyl monomer units, then the monomer (a) can be a monomer containing isoprene and aromatic vinyl monomers. Furthermore, if the polymer block (A) is a polymer block having units containing vinyl compounds with functional groups capable of interacting with silicon dioxide, in addition to isoprene monomer units and aromatic vinyl monomer units, then the monomer (a) can be a monomer containing vinyl compounds with functional groups capable of interacting with silicon dioxide, in addition to isoprene and aromatic vinyl monomers. This method will be explained below.

[0193] The polymer block (A) is not particularly limited as long as it contains isoprene monomer units. It can be a polymer block formed solely of isoprene monomer units, or it can be a polymer block formed of isoprene monomer units and monomer units other than isoprene monomer units. As a monomer unit other than isoprene monomer units in this case, aromatic vinyl monomer units are preferably examples, and polymer block (A) is preferably a polymer block that contains aromatic vinyl monomer units in addition to isoprene monomer units.

[0194] The isoprene monomer unit content in the polymer block (A) is preferably 50% by weight or more, more preferably 70% by weight or more, and even more preferably 90% by weight or more. Furthermore, there is no particular upper limit to the isoprene monomer unit content, but it is preferably 99% by weight or less. By ensuring the isoprene monomer unit content in the polymer block (A) is within the above range, when fillers such as silica are incorporated into the conjugated diene polymer, the affinity between the conjugated diene polymer and fillers such as silica can be further improved. This results in a balanced and effective improvement in the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslink, and fuel economy.

[0195] As the aromatic vinyl monomer used to form the aromatic vinyl monomer unit included in the polymer block (A), the same monomers as those described above can be used, among which styrene is preferred. Furthermore, these aromatic vinyl monomers can be used alone or in combination of two or more. The content of the aromatic vinyl monomer unit in the polymer block (A) is preferably 50% by weight or less, more preferably 30% by weight or less, and even more preferably 10% by weight or less. Moreover, the lower limit of the content of the aromatic vinyl monomer unit is not particularly limited, but is preferably 1% by weight or more.

[0196] Alternatively, at least one of the polymer block (A) constituting the conjugated diene polymer and the polymer block (B) described later may include a unit containing a vinyl compound with a functional group capable of interacting with silicon dioxide. In this case, the unit containing the vinyl compound with a functional group capable of interacting with silicon dioxide may be contained only in polymer block (A), only in polymer block (B), or in both polymer block (A) and polymer block (B).

[0197] In the case where it is contained in polymer block (A), in the case where it is contained in polymer block (B), or in the case where it is contained in both, the proportion of the vinyl compound unit containing the functional group capable of interacting with silica is preferably adjusted in such a way that the proportion of the vinyl compound unit relative to all the monomer units constituting the conjugated diene polymer is preferably in the range of 0.01 to 20% by weight, more preferably in the range of 0.02 to 2% by weight, and particularly preferably in the range of 0.03 to 1% by weight. By keeping the proportion of the vinyl compound unit containing the functional group capable of interacting with silica within the above range, the processability of the conjugated diene polymer, the abrasion resistance of the obtained rubber crosslinked product, and the balance of fuel economy can be improved, thereby also improving operational stability.

[0198] In addition to isoprene monomer units, and units of aromatic vinyl monomer units and vinyl compounds containing functional groups capable of interacting with silicon dioxide, polymer block (A) may also contain other monomer units as desired. Examples of other compounds used to constitute these monomer units include: chain olefin compounds such as ethylene, propylene, and 1-butene; cyclic olefin compounds such as cyclopentene and 2-norbornene; conjugated diene monomers other than isoprene such as 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2-chloro-1,3-butadiene, 1,3-pentadiene, and 1,3-hexadiene; and non-conjugated diene monomers such as 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene. These other monomers can be used individually or in combination of two or more. The proportion of other monomer units in the polymer block (A) is preferably 20% by weight or less, more preferably 10% by weight or less, and even more preferably 6% by weight or less.

[0199] The polymer block (A) is formed by polymerizing a monomer (a) containing isoprene in an inactive solvent using a polymerization initiator. The resulting polymer block (A) is a polymer block with active ends.

[0200] In order to form the polymer block (A), the same inert solvent as described above can be used as the inert solvent used in the polymerization of the monomer. The amount of inert solvent used is preferably an amount that makes the monomer concentration 1 to 80% by weight, more preferably an amount that makes the monomer concentration 10 to 50% by weight.

[0201] As for the polymerization initiator used to form the polymer block (A), there is no particular limitation as long as it is a polymerization initiator capable of polymerizing the monomer (a) containing isoprene to form a polymer chain with active ends. As a specific example, the same polymerization initiator as described above can be used.

[0202] The amount of polymerization initiator used can be determined based on the target molecular weight, and is preferably 4 to 250 mmol, more preferably 6 to 200 mmol, and particularly preferably 10 to 70 mmol per 100g of monomer (a) containing isoprene.

[0203] The polymerization temperature for polymerizing the monomer (a) containing isoprene is preferably -80 to +150°C, more preferably 0 to 100°C, and even more preferably 20 to 90°C. As the polymerization method, any method such as batch or continuous polymerization can be used. Furthermore, the bonding mode of each monomer when forming copolymer chains from polymer blocks (A) can be various, such as block, conical, and random bonding modes.

[0204] Furthermore, in order to adjust the vinyl bond content in the isoprene monomer unit of the polymer block (A), it is preferable to add a polar compound to the inactive solvent during polymerization. The same polar compound as described above can be used. The amount of polar compound used is determined based on the target vinyl bond content, and is preferably 0.01 to 30 moles, more preferably 0.05 to 10 moles, relative to 1 mole of polymerization initiator. When the amount of polar compound used is within the above range, the vinyl bond content in the isoprene monomer unit is easily adjusted, and abnormalities caused by deactivation of the polymerization initiator are less likely to occur. Furthermore, by increasing the amount of polar compound used within the above range, the vinyl bond content in the isoprene monomer unit can be increased.

[0205] The vinyl bond content in the isoprene monomer unit of the polymer block (A) is preferably 5 to 90% by weight, more preferably 5 to 80% by weight. By keeping the vinyl bond content in the isoprene monomer unit within the above range, the fuel economy of the obtained rubber crosslink can be further improved. Furthermore, in this specification, the vinyl bond content in the isoprene monomer unit refers to the total metric ratio of isoprene monomer units having a 1,2-structure and isoprene monomer units having a 3,4-structure.

[0206] The weight-average molecular weight (Mw) of the polymer block (A) is preferably in the range of 1,000 to 30,000, more preferably in the range of 1,500 to 20,000, and even more preferably in the range of 2,000 to 10,000. By ensuring that the weight-average molecular weight (Mw) of the polymer block (A) is within the above range, the fuel economy of the obtained rubber crosslinked compound can be further improved.

[0207] Furthermore, the molecular weight distribution, expressed as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the polymer block (A) (Mw / Mn), is preferably 1.0 to 1.5, more preferably 1.0 to 1.3. When the value of the molecular weight distribution (Mw / Mn) of the polymer block (A) is within the above range, the manufacture of the conjugated diene polymer becomes easier. In addition, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polymer block (A) can be determined as polystyrene equivalents by gel permeation chromatography.

[0208] The polymer block (B) is not particularly limited as long as it contains a 1,3-butadiene monomer unit. It can be a polymer block formed solely of a 1,3-butadiene monomer unit, or it can be a polymer block composed of a 1,3-butadiene monomer unit and monomer units other than the 1,3-butadiene monomer unit. As a monomer unit other than the 1,3-butadiene monomer unit in this case, an aromatic vinyl monomer unit is preferably mentioned, and the polymer block (B) is preferably a polymer block that contains an aromatic vinyl monomer unit in addition to the 1,3-butadiene monomer unit.

[0209] The content of 1,3-butadiene monomer units in polymer block (B) is preferably 45% by weight or more, more preferably 50 to 94.98% by weight, and even more preferably 55 to 89.97% by weight. By keeping the content of 1,3-butadiene monomer units in polymer block (B) within the above range, the manufacture of conjugated diene polymers becomes easier.

[0210] As the aromatic vinyl monomer used to form the aromatic vinyl monomer unit contained in the polymer block (B), the same monomer as the aromatic vinyl monomers described above can be used, among which styrene is preferred. The content of the aromatic vinyl monomer unit is preferably 54.99% by weight or less, more preferably 5 to 49.98% by weight, and even more preferably 10 to 44.97% by weight.

[0211] Furthermore, it is preferable that at least one of the polymer blocks (A) and polymer blocks (B) contains a unit containing a vinyl compound with a functional group capable of interacting with silica. From the viewpoint of achieving a better balance between the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslink, and fuel economy, it is more preferable that at least one unit containing a vinyl compound with a functional group capable of interacting with silica is included in polymer block (B). When polymer block (B) contains a unit containing a vinyl compound with a functional group capable of interacting with silica, the proportion of such a unit is not particularly limited, but it is preferable that the proportion relative to the total proportion of all monomer units constituting the conjugated diene polymer of the present invention falls within the aforementioned preferred range.

[0212] Furthermore, in addition to the 1,3-butadiene monomer unit, and the aromatic vinyl monomer unit and vinyl compound containing functional groups capable of interacting with silica, the polymer block (B) may also contain other monomer units as desired. As other compounds constituting such monomer units, isoprene may be used, in addition to the same compounds exemplified in the polymer block (A) above (wherein 1,3-butadiene is excluded). The content of other monomer units in the polymer block (B) is preferably 40% by weight or less, more preferably 35% by weight or less, and even more preferably 25% by weight or less.

[0213] Polymer block (B) is formed by continuing the polymerization reaction of the polymer block (A) with active ends described above with a monomer (b) containing 1,3-butadiene, and thus being linked to polymer block (A). The formed polymer block (B) becomes a polymer block with active ends. On the other hand, the active ends disappear from polymer block (A).

[0214] In order to form the polymer block (B), there is no particular limitation on the inactive solvent used in the polymerization of the polymer block (A) and the monomer (b) containing 1,3-butadiene, and the same inactive solvent as described above can be used.

[0215] The amount of polymer block (A) with active ends used when forming polymer block (B) can be determined according to the target molecular weight, and is preferably 0.1 to 5 mmol, more preferably 0.15 to 2 mmol, and even more preferably 0.2 to 1.5 mmol relative to 100g of monomer (b) containing 1,3-butadiene.

[0216] The method of mixing the polymer block (A) with the monomer (b) containing 1,3-butadiene is not particularly limited. The polymer block (A) with an active end can be added to a solution of the monomer (b) containing 1,3-butadiene, or the monomer (b) containing 1,3-butadiene can be added to a solution of the polymer block (A) with an active end. From the viewpoint of controlling polymerization, the method of adding the polymer block (A) with an active end to a solution of the monomer (b) containing 1,3-butadiene is preferred.

[0217] The polymerization temperature for polymerizing the monomer (b) containing 1,3-butadiene is preferably -80 to +150°C, more preferably 0 to 100°C, and even more preferably 20 to 90°C. As the polymerization method, either batch or continuous polymerization can be used. When the polymer block (B) is formed into a copolymer chain, batch polymerization is preferred from the viewpoint of easily controlling the randomness of bonding.

[0218] When polymer blocks (B) are formed into copolymer chains, the bonding of the monomers can take various forms, such as block, cone, and random. Among these, random bonding is preferred. By adopting a random form, the fuel economy of the resulting rubber crosslinked compound can be further improved.

[0219] Furthermore, in one aspect of the present invention, in order to adjust the vinyl bond content in the 1,3-butadiene monomer unit of the polymer block (B), it is preferable to add a polar compound to the inactive solvent during polymerization, similar to the method used when adjusting the vinyl bond content in the isoprene monomer unit of the polymer block (A). However, when preparing the polymer block (A), if a polar compound is added to the inactive solvent in an amount sufficient to adjust the vinyl bond content in the 1,3-butadiene monomer unit of the polymer block (B), it is not necessary to add a new polar compound. As the polar compound used to adjust the vinyl bond content, the same compound as described above can be used. The amount of polar compound used can be determined based on the target vinyl bond content, and is preferably adjusted to a range of 0.01 to 100 mol, more preferably 0.1 to 30 mol, relative to 1 mole of polymerization initiator used in the initial polymerization reaction (polymerization reaction for forming the first polymer block (A)). When the amount of polar compound used is within this range, the vinyl bond content in the 1,3-butadiene monomer unit is easily adjusted, and it is difficult to produce abnormalities due to the deactivation of the polymerization initiator.

[0220] The vinyl bond content in the 1,3-butadiene monomer unit of the polymer block (B) is preferably 1 to 90% by weight, more preferably 3 to 80% by weight, and particularly preferably 5 to 75% by weight. By keeping the vinyl bond content in the 1,3-butadiene monomer unit of the polymer block (B) within the above range, the fuel economy of the obtained rubber crosslinked product can be improved.

[0221] In this way, a polymer chain having polymer blocks (A) and polymer blocks (B) and having active ends can be obtained. From a productivity point of view, it is preferable that the polymer chain with active ends is composed of polymer blocks (A)-polymer blocks (B), and the end of polymer block (B) is the active end, but it can also be a polymer chain having multiple polymer blocks (A), or a polymer chain having other polymer blocks. Examples of polymer chains with active ends include polymer blocks (A)-polymer blocks (B)-polymer blocks (A). In this case, the active end is formed at the end of the polymer block (A) formed following the polymer block (B). When the polymer block (A) is formed on the active end side of the conjugated diene polymer, the amount of isoprene used is preferably 10 to 100 moles, more preferably 15 to 70 moles, and particularly preferably 20 to 35 moles, relative to 1 mole of polymerization initiator used in the initial polymerization reaction (polymerization reaction for forming the first polymer block (A)).

[0222] The weight ratio of polymer block (A) to polymer block (B) in the polymer chain with active ends (in the case of multiple polymer blocks (A) and polymer blocks (B), the weight ratio is based on their total weight) is expressed as (weight of polymer block (A)) / (weight of polymer block (B)), preferably 0.001 to 0.2, more preferably 0.005 to 0.1, and particularly preferably 0.01 to 0.05. By keeping the weight ratio of polymer block (A) to polymer block (B) within the above range, a better balance can be achieved between the processability of the conjugated diene polymer, the abrasion resistance of the resulting rubber crosslinked product, and fuel economy.

[0223] As described above, conjugated diene polymers can be obtained in inert solvents. Furthermore, the conjugated diene polymers obtained in this way are typically polymers with active ends.

[0224] For conjugated diene polymers containing active terminals, coupling polymer chains can also be formed by reacting with coupling agents. No particular limitation is made to coupling agents, but examples include: silicon tetrachloride, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, tin tetrachloride, methyltin trichloride, dimethyltin dichloride, trimethyltin chloride, tetramethoxysilane, methyltrimethoxysilane, dimethoxydimethylsilane, methyltriethoxysilane, ethyltrimethoxysilane, dimethoxydiethylsilane, diethoxydimethylsilane, tetraethoxysilane, ethyltriethoxysilane, diethoxydiethylsilane, bis(trichlorosilyl)methane, 1,2-bis(trichlorosilyl)ethane, 1,3-bis(trichlorosilyl)propane, 1,4-bis(trichlorosilyl)butane, 1,5-bis(trichlorosilyl)pentane, 1,6-bis(trichlorosilyl)hexane, etc. Among these, from the viewpoint of improving the mechanical properties of the obtained rubber crosslinked product while fully maintaining the processability of the conjugated diene polymer, it is preferable to use a coupling agent with trifunctionality or higher, and more preferably a coupling agent with tetrafunctionality or higher.

[0225] When using a coupling agent, it is preferable to perform a coupling reaction on a portion of the polymer chain with active ends obtained by the above-described polymerization method, thereby forming a coupled polymer chain and obtaining a solution containing both the polymer chain with active ends and the coupled polymer chain. The amount of coupling agent used in this case is not particularly limited, but from the viewpoint of easily performing a coupling reaction on only a portion of the polymer chain with active ends, it is preferable to use less than 1 mole relative to 1 mole of the polymerization initiator used for polymerization initiation, preferably 0.01 to 0.4 moles, and more preferably 0.02 to 0.3 moles. By using the amount of coupling agent within the above range, the fuel economy of the obtained rubber crosslinked product can be further improved. With the addition of the coupling agent, the polymer chain with active ends undergoes a coupling reaction at its active ends, thereby causing the active ends of the polymer chain after the coupling reaction to disappear, resulting in a polymer chain without active ends.

[0226] For a portion of the polymer chain with active ends, after the coupling reaction, it is preferable to further polymerize the polymer chain with active ends other than the polymer chain after the coupling reaction, using a monomer containing a conjugated diene compound. These reactions are preferably carried out continuously, specifically, preferably in the following manner: after initiating polymerization, while continuing the polymerization reaction, a coupling reaction is carried out by adding a coupling agent, followed by a polymerization reaction after the coupling reaction.

[0227] As monomers used for polymerization after the coupling reaction, any monomer containing at least a conjugated diene monomer is acceptable. From the viewpoint of making the conjugated diene polymer a polymer having conjugated diene monomer units and aromatic vinyl monomer units, monomers containing aromatic vinyl monomers are preferred. Furthermore, in polymerization after the coupling reaction, monomers containing vinyl compounds with functional groups capable of interacting with silica are preferred. By using vinyl compounds with functional groups capable of interacting with silica, units containing vinyl compounds with functional groups capable of interacting with silica can be preferentially introduced into polymer chains other than the polymer chains after the coupling reaction. Moreover, this effectively increases the adsorption rate of silica on polymer chains other than the polymer chains after the coupling reaction, resulting in good processability and further improved fuel economy of the obtained rubber crosslinked product.

[0228] Furthermore, the polymerization after the coupling reaction can be carried out in a non-reactive solvent. There are no particular limitations on the non-reactive solvent; the same solvent as described above can be used. The polymerization temperature and polymerization method are also not particularly limited, as long as they are the same as those described above. Moreover, the bonding mode of each monomer can be various, such as block, cone, and random bonding. Among these, random bonding is preferred. By using a random bonding mode, the fuel economy of the resulting rubber crosslinked compound can be further improved.

[0229] Furthermore, it is preferable to add the polymerization initiator at the initiation of polymerization after the coupling reaction or at a point during polymerization. There are no particular limitations on the timing or number of times the polymerization initiator is added; it can be determined based on the desired molecular weight distribution of the conjugated diene polymer. There are no particular limitations on the amount of polymerization initiator added during the addition operation; preferably 0.1 to 0.7 moles, more preferably 0.2 to 0.6 moles, relative to 1 mole of polymerization initiator used during polymerization initiation.

[0230] Furthermore, from the viewpoint of making the effects of the present invention more significant, it is preferable to react the modifier with the active ends contained in the conjugated diene polymer obtained by polymerization, or with the active ends that the conjugated diene polymer after coupling reaction can contain, so that the conjugated diene polymer becomes a conjugated diene polymer with modified groups (modified conjugated diene polymer). As a modifier, the above-mentioned modifier can be used as a modifier for forming the modified groups that the conjugated diene polymer of the present invention can contain. In addition, by using a modifier capable of coupling (e.g., polyorganosiloxane) as a modifier, the number of peaks in the molecular weight distribution curve of the conjugated diene polymer can be controlled.

[0231] When using siloxane compounds as modifiers, it is preferable to react the polymer chain with the active terminal, the siloxane compound, and the organometallic compound, thereby improving the processability of the conjugated diene polymer. Examples of organometallic compounds used in this process include organoalkali metal compounds, such as organolithium compounds, organosodium compounds, and organopotassium compounds. Specifically, examples include: organomonal lithium compounds such as n-butyllithium, sec-butyllithium, tert-butyllithium, hexyllithium, phenyllithium, and lithium stilbene; organopolylithium compounds such as dilithium methane, 1,4-dilithium butane, 1,4-dilithium-2-ethylcyclohexane, 1,3,5-trilithiumbenzene, and 1,3,5-tris(lithium methyl)benzene; organosodium compounds such as sodium naphthalene; and organopotassium compounds such as potassium naphthalene. Among these organometallic compounds, n-butyllithium is preferred. Furthermore, the amount of organometallic compound used is preferably 0.05 to 10 moles, more preferably 0.01 to 5 moles, relative to 1 mole of siloxane compound used. When the amount of organometallic compound used is within the above range, the processability of the conjugated diene polymer can be improved. One organometallic compound can be used alone, or two or more can be used in combination.

[0232] As a method for reacting polymer chains with active ends, siloxane compounds, and organometallic compounds, examples include: mixing polymer chains with active ends with siloxane compounds and then mixing with organometallic compounds; mixing polymer chains with active ends with organometallic compounds and then mixing with siloxane compounds; and simultaneously adding siloxane compounds and organometallic compounds (or sequentially adding siloxane compounds and organometallic compounds) to polymer chains with active ends and then mixing them. From the viewpoint of further improving the processability of conjugated diene polymers, the method of mixing polymer chains with active ends with organometallic compounds and then mixing with siloxane compounds is preferred.

[0233] In the method of mixing a polymer chain with active ends with an organometallic compound and a siloxane compound, the organometallic compound is added to the polymerization solution used in the polymerization to obtain the polymer chain with active ends. This method of adding the siloxane compound to the mixed solution after mixing is simple and therefore preferred. Furthermore, the organometallic compound is preferably dissolved in an inactive solvent and added to the polymerization solution, with a solution concentration preferably in the range of 1 to 50% by weight. The temperature at which the organometallic compound is added is not particularly limited, and is typically 0 to 120°C.

[0234] There is no particular limitation on the timing of adding organometallic compounds to a solution containing polymer chains with active ends. From the viewpoint of improving the reactivity of siloxane compounds in the presence of organometallic compounds, it is preferable to add organometallic compounds to the solution after the polymerization conversion rate has reached 90% or more, more preferably 95% or more. In addition, it is preferable to add organometallic compounds to the solution when the monomer concentration is 5000 ppm or less.

[0235] When adding a siloxane compound to a solution containing polymer chains with active ends and organometallic compounds, the siloxane compound is preferably dissolved in an inactive solvent and added to the polymerization system, with a solution concentration preferably in the range of 1–50% by weight. The reaction temperature for reacting the siloxane compound is not particularly limited, typically ranging from 0 to 120°C, and the reaction time is also not particularly limited, typically ranging from 1 to 60 minutes.

[0236] Furthermore, regarding the timing of adding the siloxane compound to the solution containing the polymer chain with active ends and the organometallic compound, there are no particular limitations as long as the organometallic compound is added after the polymer chain with active ends has been in the solution. Preferably, the siloxane compound is added to the solution after mixing for 1 to 180 minutes, more preferably 5 to 60 minutes, and even more preferably 10 to 30 minutes. By adding the siloxane compound in this way, the processability of the conjugated diene polymer can be further improved.

[0237] In addition, the conjugated diene polymer obtained by mixing polymer chains with organometallic compounds and then mixing siloxane compounds is a polymer containing polymer chains with siloxane-based modified structures introduced at the ends of the polymer chains and then reacted with organometallic compounds. Alternatively, it can be a polymer containing unmodified conjugated diene polymer chains that have not undergone siloxane-based modification and siloxane-modified conjugated diene polymer chains that have not reacted with organometallic compounds.

[0238] The amount of modifier used when reacting the above-mentioned modifier with the active ends of the conjugated diene polymer is not particularly limited. The amount of modifier relative to 1 mole of the active end of the polymer chain with the active end (or, in the case of an organoalkali metal compound used as a polymerization initiator, the amount of modifier relative to 1 mole of the metal atoms in the organoalkali metal compound) 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. Furthermore, the modifier can be used alone or in combination of two or more.

[0239] Furthermore, the method for reacting the modifier with the active ends of the conjugated diene polymer is not particularly limited, and methods such as mixing the polymer chain with active ends and the modifier in a solvent capable of dissolving them can be cited. As the solvent used in this process, solvents exemplified as those used in the polymerization of the aforementioned conjugated diene polymer can be used. Moreover, this method is convenient and preferred because it allows the polymer chain with active ends to remain in the state of the polymerization solution used in the polymerization process, and the method of adding the modifier to it is simple. Additionally, the modifier can be dissolved in the inactive solvent used in the polymerization process and added to the polymerization system, with a solution concentration preferably in the range of 1 to 50% by weight. The reaction temperature is not particularly limited, typically ranging from 0 to 120°C, and the reaction time is not particularly limited, typically ranging from 1 minute to 1 hour.

[0240] There is no particular limitation on the timing of adding the modifier to a solution containing polymer chains with active ends. It is preferable to add the modifier when the polymerization reaction is not yet complete and the solution still contains monomers. More specifically, the modifier is added to the solution when it contains 100 ppm or more, more preferably 300 to 50,000 ppm of monomers. By adding the modifier in this way, side reactions between the conjugated diene polymer chains with active ends and impurities contained in the polymerization system can be suppressed, thus effectively controlling the reaction.

[0241] Preferably, polymerization terminators such as methanol and isopropanol or water are added to the active ends of the conjugated diene polymer obtained by polymerization, or to the active ends that can remain after reacting with coupling agents or modifiers as needed, to deactivate the unreacted active ends.

[0242] In the solution of the conjugated diene polymer obtained by the above method, antioxidants such as phenolic stabilizers, phosphorus stabilizers, and sulfur stabilizers may be added as needed. The amount of antioxidant added can be appropriately determined according to its type, etc. Furthermore, as needed, it can be combined with filler oil to produce oil-extended rubber. Examples of filler oils include paraffinic, aromatic, and cycloalkane-based petroleum-based softeners, plant-based softeners, and fatty acids. When using petroleum-based softeners, it is preferable that the content of polycyclic aromatic hydrocarbons extracted by the IP346 method (the British Petroleum Institute's testing method) is less than 3%. When using filler oil, its amount used is typically 5 to 100 parts by weight relative to 100 parts by weight of the conjugated diene polymer.

[0243] Moreover, the conjugated diene polymer obtained in this way can be separated from the reaction mixture by removing the solvent by any method, such as steam stripping or heating the mixture under reduced pressure, thereby obtaining it as a solid conjugated diene polymer.

[0244] As desired, two or more conjugated diene polymers with different monomer compositions, molecular structures, and molecular weight distribution curves can be mixed to obtain the conjugated diene polymers of the present invention. When mixing two or more conjugated diene polymers, they can be mixed in a polymer solution state or in a solid state; preferably, they can be mixed in a solution state. That is, more preferably, solutions of the two or more conjugated diene polymers for mixing are prepared separately, and the prepared solutions are then mixed.

[0245] <Rubber Composition>

[0246] The rubber composition of the present invention is a composition containing the conjugated diene polymer and filler of the present invention described above.

[0247] The rubber composition of the present invention may contain other polymers besides the conjugated diene polymers of the present invention described above. Other polymers refer to, 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), grafted natural rubber, etc.), polyisoprene rubber, emulsion-polymerized styrene-butadiene copolymer rubber, solution-polymerized styrene-butadiene copolymer rubber, polybutadiene rubber (which may be high cis-BR, low cis-BR. In addition, it may also be polybutadiene rubber containing crystalline fibers formed from 1,2-polybutadiene polymers), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, acrylonitrile-styrene-butadiene copolymer rubber, butyl rubber (IIR), ethylene-propylene copolymer, chloroprene rubber, nitrile chloroprene rubber, and nitrile isoprene rubber, etc., other than 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 with polybutadiene rubber or natural rubber with styrene-butadiene copolymer rubber.

[0248] 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 50 to 100% by weight. By including the conjugated diene polymer of the present invention in the polymer component in such a proportion, a better balance can be achieved between the processability of the rubber composition, the abrasion resistance of the resulting rubber crosslinks, and fuel economy.

[0249] 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, and silica is more preferred, from the perspective of further improving the abrasion resistance of the obtained rubber crosslinked product. These can be used alone or in combination of two or more.

[0250] Examples of silica include dry-process silica, wet-process silica, colloidal silica, precipitated silica, calcium silicate, and aluminum silicate. Among these, wet-process silica, primarily composed of hydrated silicic acid, is preferred. Additionally, carbon-silica dual-phase fillers with silica supported on the surface of carbon black can also be used. These silicas can be used individually or in combination of two or more. The nitrogen adsorption specific surface area of ​​the silica used (determined by the BET method according to ASTM D3037-81) is preferably 20–400 m². 2 / g, more preferably 50-220m 2 / g, particularly preferably 80-170mg 2 / g. Furthermore, the pH of silica is preferably 5–10.

[0251] As silicon dioxide, various commercially available silicon dioxides can be used. Examples include: PPG Industries' "Hi-Sil210", "Hi-Sil233", and "Hi-Sil243LD"; Solvay's "Zeosil1115MP", "Zeosil1165MP", and "Zeosil165GR"; Evonik's "ULTRASIL VN2" and "ULTRASIL VN3"; and Tosoh Silicon Chemicals Co., Ltd.'s "NIPSIL VN3", "NIPSIL AQ", "NIPSIL ER", and "NIPSIL RS-150", etc.

[0252] Examples of carbon black include furnace black, acetylene black, thermal cracking black, channel black, and graphite. Examples of channel black include EPC, MPC, and CC. Examples of furnace black include SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF, and ECF. Examples of thermal cracking black include FT and MT. Carbon black can be used alone or in combination of two or more types.

[0253] Relative to 100 parts by weight of polymer in the rubber composition, the amount of filler in the rubber composition of the present invention is preferably 10 to 250 parts by weight, more preferably 15 to 150 parts by weight, and even more preferably 20 to 130 parts by weight. By keeping the amount of filler within the above range, the processability of the rubber composition can be adequately ensured, and the fuel economy and fuel efficiency of the resulting rubber crosslinked product can be further improved in a balanced manner.

[0254] In the rubber composition of the present invention, from the viewpoint of further improving the fuel economy of the obtained rubber crosslinked product, a silane coupling agent may be further incorporated. There are no particular limitations on the silane coupling agent; various silane coupling agents can be used. In the present invention, sulfide-based, mercapto-based, protected mercapto-based (e.g., silane coupling agents having a carbonyl thio group), thiocyanate-based, vinyl-based, amino-based, methacrylate-based, epoxy-propoxy-based, nitro-based, epoxy-based, or chlorine-based silane coupling agents are preferred. Specific examples of silane coupling agents include: bis(3-(triethoxysilyl)propyl)disulfide, bis(3-triethoxysilyl)propyl)trisulfide, bis(3-(triethoxysilyl)propyl)tetrasulfide, γ-mercaptopropyltriethoxysilane, 3-[ethoxybis(3,6,9,12,15-pentaoxaoctadecane-1-yloxy)silyl]-1-propanethiol, 3-octanoylthio-1-propyl-triethoxysilane, and 3-trimethoxysilylpropyl-N,N-dimethylthioaminomethyl Acyl tetrasulfides, γ-trimethoxysilylpropylbenzothiazole tetrasulfides, 3-trimethoxysilylpropylbenzothiazole tetrasulfides, 3-thiocyanate-propyltriethoxysilane, vinyltriethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-trimethoxysilylpropylmethacrylate monosulfides, γ-epoxypropoxypropyltriethoxysilane, 3-nitropropyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and 3-chloropropyltrimethoxysilane, etc. In addition, Momentive Advanced Materials' NXT-Z100, NXT-Z30, NXT-Z45, NXT-Z60, NXT-Z45, NXT, and Evonik Degussa's Si69, Si75, and VPSi363, etc., can also be used. These silane coupling agents can be used alone or in combination of two or more. Furthermore, one or more of these agents can be pre-oligomerized and used in an oligomerized state. The amount of silane coupling agent incorporated is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight, relative to 100 parts by weight of filler.

[0255] Furthermore, the rubber composition of the present invention preferably also contains a crosslinking agent. Examples of crosslinking agents include sulfur-containing compounds such as sulfur and sulfur halides, organic peroxides, quinone dioximes, organic polyamine compounds, and alkylphenol resins having hydroxymethyl groups. Among these, sulfur is preferred. 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, relative to 100 parts by weight of the polymer component in the rubber composition.

[0256] Furthermore, in the rubber composition of the present invention, in addition to the above-mentioned components, crosslinking accelerators, crosslinking activators, antioxidants, activators, processing oils, plasticizers, lubricants, tackifiers and other compounding agents can be added in accordance with conventional methods in the required amounts.

[0257] When using sulfur or sulfur-containing compounds as crosslinking agents, it is preferable to use both a crosslinking accelerator and a crosslinking activator. Examples of crosslinking accelerators include: sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamate-based crosslinking accelerators; xanthic acid-based crosslinking accelerators, etc. Among these, sulfenamide-based crosslinking accelerators are preferred. These crosslinking accelerators can be used alone or in combination of two or more. The amount of crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight, relative to 100 parts by weight of polymer components in the rubber composition.

[0258] Examples of crosslinking activators include, for example, higher fatty acids such as stearic acid and zinc oxide. These crosslinking activators can be used alone or in combination of two or more. The amount of crosslinking activator is preferably 0.05 to 20 parts by weight, and particularly preferably 0.5 to 15 parts by weight, relative to 100 parts by weight of polymer in the rubber composition.

[0259] To obtain the rubber composition of the present invention, the components can be mixed using conventional methods. For example, after mixing the components other than the heat-labile components such as crosslinking agents and crosslinking accelerators with a conjugated diene polymer, the heat-labile components such as crosslinking agents and crosslinking accelerators can be mixed into the mixture to obtain the target composition. The mixing temperature of the components other than the heat-labile components and the conjugated diene polymer is preferably 80 to 200°C, more preferably 120 to 180°C, and the mixing time is preferably 30 seconds to 30 minutes. Furthermore, the mixing of the mixture with the heat-labile components is usually carried out after cooling to below 100°C, preferably below 80°C.

[0260] <Rubber Crosslinkings>

[0261] The rubber crosslinked product of the present invention is formed by crosslinking the rubber composition of the present invention described above.

[0262] The rubber crosslinked compound of the present invention can be manufactured by molding the rubber composition of the present invention using, for example, a molding machine corresponding to the desired shape, such as an extruder, injection molding machine, compressor, roller, etc., and performing a crosslinking reaction by heating, thereby fixing the shape as a rubber crosslinked compound. In this case, crosslinking can be performed after pre-molding or simultaneously with molding. The molding temperature is typically 10 to 200°C, preferably 25 to 120°C. The crosslinking temperature is typically 100 to 200°C, preferably 130 to 190°C, and the crosslinking time is typically 1 minute to 24 hours, preferably 2 minutes to 12 hours, and particularly preferably 3 minutes to 6 hours.

[0263] In addition, depending on the shape and size of the rubber crosslinker, sometimes even if the surface has been crosslinked, it has not been fully crosslinked into the interior. Therefore, it can be further heated to carry out secondary crosslinking.

[0264] As for heating methods, any commonly used methods for crosslinking rubber, such as pressing heating, steam heating, oven heating, or hot air heating, can be appropriately selected.

[0265] The rubber crosslinked compound of the present invention thus obtained is derived using the conjugated diene polymer of the present invention described above, and therefore exhibits excellent fuel economy and abrasion resistance. Therefore, the rubber crosslinked compound of the present invention can effectively utilize its excellent properties for applications such as: materials for various parts of tires, including the tread, base tread, carcass, sidewall, and bead portion; materials for hoses, belts, pads, shock-absorbing rubber, and various other industrial products; resin impact modifiers; resin film cushioning agents; shoe soles; rubber shoes; golf balls; toys, and various other uses. In particular, the rubber crosslinked compound of the present invention is suitable for use as a tire material due to its excellent fuel economy and abrasion resistance.

[0266] Example

[0267] The present invention will be further described below based on detailed embodiments, but the present invention is not limited to these embodiments. Furthermore, unless otherwise specified, "parts" and "%" in the examples are by weight. Various measurements and evaluations are performed according to the following methods.

[0268] <Styrene unit content, vinyl bond quantity>

[0269] The content of styrene units (wt%) and the amount of vinyl bonds in the conjugated diene monomer units (mol%) were determined according to JIS K6239 (2007) by... 1 Determined by H-NMR method.

[0270] <Styrene Block Ratio>

[0271] The styrene block ratio, as the block ratio of aromatic vinyl monomers, was determined by 1H-NMR using deuterated chloroform as solvent, referring to the following literature. The peaks from 6.1 to 7.7 ppm in the obtained 1H-NMR spectrum were taken as those originating from styrene, with the peaks from 6.1 to 6.88 ppm taken as those originating from styrene blocks. The ratio of the peak area originating from styrene blocks to the peak area originating from styrene was calculated, multiplied by 2.5, and expressed as a percentage as the styrene block ratio.

[0272] References: Sardelis, K. Michels, H. J. Allen, G. Polymer, 1984, 25, 1011

[0273] Mooney viscosity of conjugated diene polymers

[0274] Mooney viscosity (ML1+4) of conjugated diene polymers was determined according to JIS K6300-1:2013 under the following conditions.

[0275] • Test temperature: 100℃

[0276] Rotor type: L-shaped

[0277] • Testing machine used: Shimadzu Mooney Viscometer SMV-300J, manufactured by Shimadzu Corporation.

[0278] <Silicon content>

[0279] The silicon content was determined by X-ray fluorescence spectrometry of compressed sheets obtained by pressing conjugated diene polymers (A) to (L). The pressing conditions and X-ray fluorescence spectrometry conditions are described below.

[0280] (Compression molding conditions)

[0281] Using a compression molding machine (model AYSR-10) manufactured by Shinto Metal Industries, Ltd., the conjugated diene polymer was heated for 5 minutes at 150°C without pressure. Then, the heating and pressing process was repeated 20 times for 5 minutes each at 150°C and a maximum pressure of 5 MPa. Following this, the material was rapidly cooled at 25°C without pressure to obtain a compressed sheet (25 mm in diameter and 30 mm in thickness). Furthermore, to prevent the conjugated diene polymers (A) to (L) from contacting the metal, compression molding was performed using a mold covered with a PTFE film (NAFLON tape TOMBO9001, manufactured by Nigas Corporation).

[0282] (X-ray fluorescence measurement conditions)

[0283] An X-ray fluorescence apparatus (ZSX Primus II, manufactured by Rigaku Corporation) was used for the X-ray fluorescence determination. A pressed sheet was placed on a sample holder, and a membrane (Ultra-Polyester, 1.5 μm thick, manufactured by Chemplex Industries) was adhered to the measurement surface. For the obtained sample, X-ray fluorescence determination was performed under the following conditions, and the silicon content was determined based on the calibration curve shown below.

[0284] (i) Measurement conditions: X-ray tube Rh 30kV 100mA, aperture Φ20mm

[0285] (ii) Measurement environment: vacuum

[0286] (iii) Calibration curve

[0287] Polyethylene standard material (RRM-PE-01, manufactured by Rigaku Corporation) was used as the standardized sample for the calibration curve. X-ray fluorescence was measured for standardized samples with silicon contents of 82 ppm by weight, 544 ppm by weight, and 808 ppm by weight to construct a linear calibration curve.

[0288] <Ion strength index>

[0289] The sample solution containing conjugated diene polymers (A) to (L) and internal standard polystyrene was subjected to GPC measurements using a styrene-based column and GPC measurements using a cation exchange column. Based on the results, the ionic strength index was calculated according to the following formula (I).

[0290] Ionic strength index (%) = {1 - (A)} CX / B CX )×(B sty / A sty )}×100 (I)

[0291] A CX Peak area of ​​molecular weight distribution curves of conjugated diene polymers determined by GPC using a cation exchange column.

[0292] B CX Peak area of ​​internal standard polystyrene determined by GPC using a cation exchange column.

[0293] B sty Peak area of ​​internal standard polystyrene determined by GPC using a styrene-based column.

[0294] A sty Peak areas of molecular weight distribution curves of conjugated diene polymers determined by GPC using a styrene-based column.

[0295] Here, ACX and A sty The molecular weight distribution curve of conjugated diene polymers in the definition 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 internal standard polystyrene.

[0296] GPC determinations using styrene-based columns were performed under the following conditions.

[0297] (GPC device and software)

[0298] (i) Liquid delivery pump: LC-20AD (manufactured by Shimadzu Corporation)

[0299] (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation)

[0300] (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation)

[0301] (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation)

[0302] (v) Differential Refractive Index Detector (RID): RID-10A (manufactured by Shimadzu Corporation)

[0303] (vi) System Controller: CBM-20A (manufactured by Shimadzu Corporation)

[0304] (vii) Analytical software: LC solution ver.1.24SP1

[0305] (viii) Measurement conditions

[0306] GPC Posts: Plus Pore Series Poly Pore 7.5mm ID×300mm (manufactured by Agilent Technologies) 2 posts

[0307] Mobile phase: 25 mg of 2-(ethylamino)ethanol (Fujifilm and Photonics Co., Ltd., extra grade, without stabilizer) was added to 3 L of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., extra grade).

[0308] Flow rate: 1 mL / min

[0309] Column oven temperature: 35℃

[0310] Detection: Differential Refractive Index Detector (RID)

[0311] RID unit temperature: 35℃

[0312] Sample solution injection volume: 100 μL

[0313] GPC column calibration standard material: PStQuick Kit-H (manufactured by Tosoh Corporation)

[0314] (ix) Sample solution preparation conditions

[0315] Solvent: Add 5 mg of standard polystyrene A5000 (manufactured by Tosoh Corporation) with a molecular weight of 5000 as an internal standard to 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., premium grade, without stabilizer).

[0316] Sample solution concentration: 0.5 mg / mL

[0317] Automatic shaker for dissolving: DF-8020 (manufactured by Tosoh Corporation)

[0318] Dissolution conditions: Place 10 mg of the sample and 20 mL of solvent into a screw-top bottle and seal. Stir with a DF-8020 at a stirring speed of 60 reciprocating strokes per minute at room temperature for 120 minutes. Filter through a syringe equipped with a filter.

[0319] Filter for filtration: Millex-LG, pore size 0.45μm, hydrophilic, PTFE, filter diameter 25mm (Merck).

[0320] The GPC assay using a cation exchange column was performed under the following conditions. Furthermore, the assay solution used in the GPC assay using a cation exchange column was the same as that used in the GPC assay using the styrene-based column described above.

[0321] (GPC device and software)

[0322] (i) Liquid delivery pump: LC-20AD (manufactured by Shimadzu Corporation)

[0323] (ii) Degasser: DGU-20A3 (manufactured by Shimadzu Corporation)

[0324] (iii) Autosampler: SIL-20A HT (manufactured by Shimadzu Corporation)

[0325] (iv) Column oven: CTO-20A (manufactured by Shimadzu Corporation)

[0326] (v) Differential Refractive Index Detector (RID): RID-10A (manufactured by Shimadzu Corporation)

[0327] (vi) System Controller: CBM-20A (manufactured by Shimadzu Corporation)

[0328] (vii) Analysis software: LC solution ver.1.24SP1

[0329] (viii) Measurement conditions

[0330] GPC columns: 2 Inertcil CX (4.6×250mm, manufactured by GL Sciences)

[0331] Mobile phase: Tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., premium grade, stabilizer-free)

[0332] Flow rate: 0.7 mL / min

[0333] Column oven temperature: 35℃

[0334] Detection: Differential Refractive Index Detector (RID)

[0335] RID unit temperature: 35℃

[0336] Sample solution injection volume: 100 μL

[0337] GPC column calibration standard material: PStQuick Kit-H (manufactured by Tosoh Corporation)

[0338] (ix) Sample solution preparation conditions

[0339] Solvent: Add 5 mg of standard polystyrene A5000 (manufactured by Tosoh Corporation) with a molecular weight of 5000 as an internal standard to 20 mL of tetrahydrofuran (manufactured by Kanto Chemical Co., Ltd., premium grade, without stabilizer).

[0340] Sample solution concentration: 0.5 mg / mL

[0341] Automatic shaker for dissolving: DF-8020 (manufactured by Tosoh Corporation)

[0342] Dissolution conditions: Place 10 mg of the sample and 20 mL of solvent into a screw-top bottle and seal. Stir with a DF-8020 at a stirring speed of 60 reciprocating strokes per minute at room temperature for 120 minutes. Filter through a syringe equipped with a filter.

[0343] Filter for filtration: Millex-LG, pore size 0.45μm, hydrophilic, PTFE, filter diameter 25mm (Merck).

[0344] <Weight-average molecular weight (Mw), molecular weight distribution (Mw / Mn), number of peaks in the molecular weight distribution curve, and peak molecular weight of each peak>

[0345] For sample solutions containing conjugated diene polymers (A) to (L) and the internal standard polystyrene, GPC analysis was performed using a styrene column, similar to the determination of the ionic strength index described above, to obtain the molecular weight distribution curve of the conjugated diene polymers. Based on the obtained molecular weight distribution curve of the conjugated diene polymers, the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) were calculated. Furthermore, the weight-average molecular weight (Mw) and number-average molecular weight (Mn) were calculated using polystyrene conversion. In addition, the obtained molecular weight distribution curve of the conjugated diene polymers was divided into regions with one maximum value sandwiched between the baseline or the minimum value. The peak area of ​​each divided region was calculated. When the peak area of ​​the overall molecular weight distribution curve of the conjugated diene polymers was set to 100%, the number of regions with a peak area of ​​1% or more was used as the number of molecular weight peaks. Furthermore, for each segmented region (limited to regions with a peak area of ​​more than 1%), the peak of the region with the lowest molecular weight is taken as the first peak. After the first peak, the regions with the lowest molecular weight are sequentially defined as the second peak, the third peak, and so on. Based on this, the peak molecular weight of each peak (the molecular weight of the region showing the maximum value) is calculated.

[0346] <Processability (Gloss of the sheet)>

[0347] By visually observing the surface of the rubber composition sheet after one mixing, a strong gloss is rated as ◎, a weak gloss as ○, and no gloss as ×. The stronger the gloss of the rubber composition sheet after one mixing, the better the processability of the conjugated diene polymer.

[0348] <Processability (cracks at the edge of the sheet)>

[0349] Visually inspecting the edges of the rubber composition sheets after one mixing step reveals the following characteristics: smooth edges without cracks are rated ◎; uneven edges without cracks are rated ○; and cracked edges are rated ×. The more effectively crack formation is suppressed at the edges of the rubber composition sheets after one mixing step, the better the processability of the conjugated diene polymer.

[0350] Processability (Silica Dispersion)

[0351] Uncrosslinked rubber compositions were processed to prepare test pieces, each 3 cm square and weighing approximately 5 g. After preheating the test pieces at 100°C for 4 minutes, the storage modulus G' at dynamic strains of 0.7% and 42% was measured using a PREMIER RPA (manufactured by Alpha Technologies) at 40°C and 10 Hz. The difference (ΔG') between the storage modulus G' at 0.7% and 42% dynamic strain was calculated. For the difference (ΔG') of storage modulus G' in each example and comparative example, the difference (ΔG') in storage modulus G' from Example 1 was calculated as an exponent of 100, representing the processability (silica dispersion) value. A higher processability (silica dispersion) value indicates better dispersion of silica in the uncrosslinked rubber composition, and consequently, better processability of the conjugated diene polymer.

[0352] Fuel Economy

[0353] The rubber crosslinked sheet was punched into short strips with a thickness of 2 mm and a length of 40 mm to obtain test pieces. For the obtained test pieces, the loss tangent (tanδ(60°C)) was measured using a viscoelasticity measuring device (manufactured by Uejima Manufacturing Co., Ltd.) under the conditions of a frequency of 10 Hz, an initial tensile rate of 10%, a strain amplitude of 2%, and a temperature of 60°C. For the loss tangent (tanδ(60°C)) in each example and comparative example, the exponent with the loss tangent (tanδ(60°C)) in Example 1 as 100 was calculated as the fuel economy value. A higher fuel economy value indicates better fuel economy of the obtained rubber crosslinked material.

[0354] <Abrasion Resistance Properties>

[0355] The rubber crosslinked sheets were subjected to the DIN abrasion test as specified in JIS K6264-2 (2005) to determine the relative abrasion volume. For the relative abrasion volumes in each example and comparative example, the index of the relative abrasion volume in Example 2 as 100 was calculated as the abrasion resistance value. The larger the abrasion resistance value, the better the abrasion resistance of the obtained rubber crosslinked material.

[0356] <Preparation of polymer blocks (A) with active ends>

[0357] In a nitrogen-replaced 800 ml container, 140.8 g of cyclohexane and 3.0 mmol of tetramethylethylenediamine were added, followed by 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 at 50 °C for 120 min to obtain a polymer block (A) with active ends. The resulting polymer block (A) had a weight-average molecular weight (Mw) of 6500, a molecular weight distribution (Mw / Mn) of 1.10, a styrene monomer content of 7.5 wt%, an isoprene monomer content of 92.5 wt%, and a vinyl bond content of 7.0 mol%.

[0358] <Manufacturing Example 1>

[0359] In a 20L autoclave equipped with a stirrer, under a nitrogen atmosphere, 7956g of industrial hexane (manufactured by Sumitomo Chemical Co., Ltd., trade name: hexane (general grade), density 0.68g / mL), 1014g of cyclohexane, 3.08mmol of tetramethylethylenediamine, 425g of 1,3-butadiene, 680g of styrene, and 4.27mmol of piperidine were added. To pre-detoxify impurities that could deactivate the polymerization, a small amount of n-butyllithium was added as a scavenging agent to the autoclave, followed by the addition of 4.27mmol of n-butyllithium, and polymerization was initiated at 55°C. After continuing the polymerization reaction for 15 minutes, 595g of 1,3-butadiene was added continuously over a period of 85 minutes. Then, after confirming that the polymerization conversion rate was in the range of 95% to 100%, after 10 minutes, the polyorganosiloxane represented by the following formula (13) was added in a manner with an epoxy group content of 3.42 mmol, and the reaction was allowed to proceed for 20 minutes. Then, 2 equivalents of methanol were added as a polymerization terminator relative to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. In this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol (manufactured by RIANOX, trade name: RIANOX1520) were added as an antioxidant relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0360] [Chemical Formula 8]

[0361]

[0362] <Manufacturing Example 2>

[0363] In a 20L autoclave equipped with a stirrer, under nitrogen conditions, 7956g of industrial hexane, 1014g of cyclohexane, 2.63mmol of tetramethylethylenediamine, 425g of 1,3-butadiene, and 680g of styrene were added. To pre-detoxify impurities that could lead to polymerization deactivation, a small amount of n-butyllithium was added as a scavenger to the autoclave, followed by the addition of the polymer block (A) with active ends obtained above, which had a lithium atom content of 4.38mmol. The polymerization growth reaction was carried out at 55°C. After continuing the polymerization reaction for 15 minutes, 595g of 1,3-butadiene was added continuously over 85 minutes. Then, after confirming that the polymerization conversion rate was in the range of 95% to 100%, 1.2mmol of n-butyllithium was added, and after another 10 minutes, the polyorganosiloxane represented by the above formula (13) was added with an epoxy group content of 3.42mmol, and the reaction was allowed to proceed for 20 minutes. Then, relative to the total amount of lithium in the autoclave, 2 equivalents of methanol were added as a polymerization terminator to obtain a solution containing a conjugated diene polymer. In this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol were added as an antioxidant relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0364] <Manufacturing Example 3>

[0365] In a 20L autoclave equipped with a stirrer, under nitrogen atmosphere, 9180g of industrial hexane, 1170g of cyclohexane, 5.2mmol of tetramethylethylenediamine, 500g of 1,3-butadiene, and 800g of styrene were added. To pre-detoxify impurities that could deactivate the polymerization, a small amount of n-butyllithium was added as a scavenger, followed by the addition of the aforementioned polymer block (A) with an active end, equivalent to 20.0mmol of lithium atoms. The polymerization growth reaction was carried out at 55°C. After continuing the polymerization reaction for 15 minutes, 700g of 1,3-butadiene was added continuously over a period of 75 minutes. Then, after confirming that the polymerization conversion rate was in the range of 95% to 100%, the polyorganosiloxane represented by formula (13) was added at a concentration of 12 mmol of epoxy groups after 10 minutes, and the reaction was allowed to proceed for 20 minutes. Then, 20 mmol of 3-(2-aminoethylamino)propyltrimethoxysilane was added, and the reaction was allowed to proceed for 15 minutes. Then, 2 equivalents of methanol were added as a polymerization terminator relative to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. In this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol were added as an antioxidant relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0366] <Manufacturing Example 4>

[0367] In a 20L autoclave equipped with a stirrer, under nitrogen atmosphere, 9180g of industrial hexane, 1170g of cyclohexane, 5.06mmol of tetramethylethylenediamine, 400g of 1,3-butadiene, and 560g of styrene were added. To pre-detoxify impurities that could deactivate the polymerization, a small amount of n-butyllithium was added as a scavenger, followed by the addition of the aforementioned polymer block (A) with an active end, equivalent to 8.03mmol of lithium atoms. The polymerization was carried out at 45°C. After 20 minutes of continued polymerization, 544g of 1,3-butadiene was added continuously over 82 minutes, followed by 96g of styrene over 60 minutes. 55 minutes after the start of chain polymerization, 0.55mmol of 1,6-bis(trichlorosilyl)hexane was added as a coupling agent. Five minutes after adding 1,6-bis(trichlorosilyl)hexane, 1.02 g of bis(diethylamino)methylvinylsilane and the aforementioned polymer block (A) with an active end, equivalent to 2.90 mmol of lithium atoms, were added. Then, after confirming that the polymerization conversion was in the range of 95% to 100%, the polyorganosiloxane represented by formula (13) was added after 10 minutes, with a total epoxy content of 11.45 mmol. The reaction time after each addition was 10 minutes. Then, 25.7 mmol of n-butyllithium was added and reacted for 10 minutes, followed by the addition of the polyorganosiloxane represented by formula (13) with an epoxy content of 8.09 mmol, and reacted for 10 minutes. Then, 2 equivalents of methanol were added as a polymerization terminator relative to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. In this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol were added as an antioxidant relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0368] <Manufacturing Example 5>

[0369] In a 20L autoclave equipped with a stirrer, under nitrogen atmosphere, 9180g of industrial hexane, 1170g of cyclohexane, 5.2mmol of tetramethylethylenediamine, 500g of 1,3-butadiene, 800g of styrene, and 0.43g of bis(diethylamino)methylvinylsilane were added. To pre-detoxify impurities that could cause polymerization deactivation, a small amount of n-butyllithium was added as a scavenger to the autoclave, followed by the addition of the polymer block (A) with an active end, equivalent to 20.0mmol of lithium atoms. The polymerization growth reaction was carried out at 55°C. After continuing the polymerization reaction for 15 minutes, 0.86g of bis(diethylamino)methylvinylsilane was added, followed by the continuous addition of 700g of 1,3-butadiene over 75 minutes. Then, after confirming that the polymerization conversion rate was in the range of 95% to 100%, the polyorganosiloxane represented by formula (13) was added after 10 minutes, with an epoxy group content of 12 mmol, and the reaction was allowed to proceed for 20 minutes. Then, 2 equivalents of methanol were added as a polymerization terminator relative to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. In this solution, 0.20 parts of 2,4-bis(octylthiomethyl)-6-methylphenol were added as an antioxidant relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0370] <Manufacturing Example 6>

[0371] Without adding the polyorganosiloxane represented by the above formula (13), the same operation as in Manufacturing Example 1 was performed to obtain a polymer solution.

[0372] <Manufacturing Example 7>

[0373] In a 20L autoclave equipped with a stirrer, under a nitrogen atmosphere, 7650g of industrial hexane, 2925g of cyclohexane, 8.81mL of tetrahydrofuran, 0.88mL of ethylene glycol dibutyl ether, 248g of 1,3-butadiene, and 526g of styrene were added. To pre-detoxify impurities that could deactivate the polymerization, a small amount of n-butyllithium was added as a scavenging agent to the autoclave, followed by 3.16mmol of n-butyllithium, and polymerization was initiated at 43°C. After continuing the polymerization reaction for 20 minutes, 680g of 1,3-butadiene was added continuously over 200 minutes, followed by 93g of styrene over 55 minutes. Then, after confirming that the polymerization conversion was in the range of 95% to 100%, 0.31mmol of silicon tetrachloride was added after 10 minutes, and the reaction was allowed to proceed for 30 minutes. Then, 1.5 equivalents of methanol were added as a polymerization terminator relative to the total amount of lithium in the autoclave to obtain a solution containing a conjugated diene polymer. In this solution, 0.40 parts of 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenylacrylate (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer GM) and 0.20 parts of pentaerythritol tetra(3-lauryl thiopropionate) (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumilizer TP-D) were added as antioxidants relative to 100 parts of the conjugated diene polymer to obtain a polymer solution.

[0374] <Manufacturing Example 8>

[0375] Without adding 1.2 mmol of n-butyllithium and the polyorganosiloxane represented by the above formula (13), the same operation as in Manufacturing Example 2 was performed to obtain a polymer solution.

[0376] <Manufacturing Example 9>

[0377] The tetramethylethylenediamine was changed to 5.37 mmol, and the polyorganosiloxane represented by the above formula (13) was not added. Otherwise, the same operation as in manufacturing example 5 was performed to obtain a polymer solution.

[0378] <Manufacturing Example 10>

[0379] After 15 minutes from polymerization initiation, 1.83 g of bis(diethylamino)methylvinylsilane was added, and 6.41 mmol of [3-(diethylamino)propyl]trimethoxysilane was added in place of the polyorganosiloxane represented by formula (13) above. The reaction was carried out for 15 minutes, and otherwise the same operation as in manufacturing example 1 was performed to obtain a polymer solution.

[0380] [Examples 1-8 and Comparative Examples 1-4]

[0381] Table 1 shows the mass ratio of each conjugated diene polymer contained in the polymer solutions obtained in Examples 1-10 to the mass of oil (manufactured by Nippon Oil Co., Ltd., trade name "Aromax T-DAE"). The polymer solutions and oil were mixed and stirred until homogeneous. The solvent was removed by steam stripping, and the mixture was dried in a vacuum dryer set to 60°C for 24 hours to obtain conjugated diene polymers (A) to (L). The content of styrene units, the amount of vinyl bonds, the styrene block ratio, Mooney viscosity, silicon content, ionic strength index, weight-average molecular weight (Mw), molecular weight distribution (Mw / Mn), the number of peaks in the molecular weight distribution curve, and the peak molecular weight of each peak were measured and evaluated in the obtained conjugated diene polymers (A) to (L). The results are shown in Table 1.

[0382] The conjugated diene polymers (A) to (L) of Examples 1-8 and Comparative Examples 1-4 were kneaded for 30 seconds in a 250 mL Labo Plastomill. Then, materials other than sulfur and vulcanization accelerators were added according to the proportions (parts by weight) shown in Table 2, and the mixture was further kneaded for 3.5 minutes. The rubber composition after one-time kneading was discharged from the Labo Plastomill. The indicated temperature of the Labo Plastomill at the time of discharge was 140°C. The resulting one-time kneaded rubber composition was passed twice directly through an open roller with a gap width set to 1.5 mm and a temperature set to 50°C to obtain a one-time kneaded rubber composition sheet. The processability (sheet gloss) and processability (cracks at the sheet edges) of the obtained one-time kneaded rubber composition sheet were evaluated. The results are shown in Table 2.

[0383] Next, the rubber composition sheet after one-time mixing was wound on an open roller set to 50°C, sulfur and a vulcanization accelerator were added, and they were mixed to obtain a sheet-like uncrosslinked rubber composition. The processability (silica dispersion) of the obtained uncrosslinked rubber composition was evaluated. The results are shown in Table 2.

[0384] The uncrosslinked rubber composition obtained above was crosslinked by heating at 160°C for 30-35 minutes to obtain crosslinked rubber sheets. The fuel economy and abrasion resistance of the obtained crosslinked rubber sheets were evaluated. The results are shown in Table 2.

[0385] [Table 1]

[0386]

[0387] [Table 2]

[0388]

[0389] In addition, the materials shown in Table 2 are described below.

[0390] • Silica: Manufactured by Evonik Industries, trade name "ULTRASIL (registered trademark) 7000GR"

[0391] Oil: Manufactured by Nippon Oil Co., Ltd., trade name "Aromax T-DAE"

[0392] • Silane coupling agent: bis(3-(triethoxysilyl)propyl)tetrasulfide (manufactured by Degussa, trade name "Si69")

[0393] • Carbon black: Manufactured by Cabot Japan, trade name "N339"

[0394] • Zinc oxide: Manufactured by Zhengtong Chemical Industry Co., Ltd., trade name "Zinc Oxide (2 types)"

[0395] Antioxidant: 6PPD, N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name "Nocrac 6C")

[0396] • Stearic acid: Manufactured by Nippon Oil Co., Ltd., trade name "Beaded Stearic Acid Camellia".

[0397] • Sulfur: Manufactured by Tsurumi Chemical Co., Ltd., trade name "Sulfur 325 Mesh"

[0398] • Vulcanization accelerator (1): N-cyclohexyl-2-benzothiazolyl sulfenamide (manufactured by Ouchi Shinshin Chemical Industry Co., Ltd., trade name "Nocceler CZ-G")

[0399] • Vulcanization accelerator (2): Diphenylguanidine (manufactured by Ouchi Shinsei Chemical Co., Ltd., trade name "NoccelerD")

[0400] Based on Tables 1 and 2, the following can be confirmed.

[0401] That is, the conjugated diene polymers, which are conjugated diene polymers with a silicon content of 95 ppm or more by weight and an ionic strength index of 75% or less, have excellent processability and can form rubber crosslinks with excellent wear resistance and fuel economy (Examples 1 to 8).

[0402] On the other hand, when the silicon content is less than 95 ppm by weight and the ionic strength index is greater than 75%, the balance between processability, abrasion resistance of the obtained rubber crosslinks and fuel economy is poor (Comparative Examples 1-4).

Claims

1. A conjugated diene polymer, which contains at least a conjugated diene monomer unit, the silicon content of the conjugated diene polymer is 95 ppm by weight or more, the ionic strength index is 45% or less, and the weight average molecular weight (Mw) is 500,000 to 10 million.

2. The conjugated diene polymer of claim 1, wherein, the molecular weight distribution (Mw / Mn) of the conjugated diene polymer is 1.5 or more.

3. The conjugated diene polymer according to claim 1 or 2, wherein, the silicon content of the conjugated diene polymer is 150 ppm by weight or more.

4. The conjugated diene polymer according to claim 1 or 2, wherein, the ionic strength index of the conjugated diene polymer is 0.5 to 45%.

5. The conjugated diene polymer according to claim 1 or 2, wherein, the number of peaks in the molecular weight distribution curve of the conjugated diene polymer is 2 or more.

6. The conjugated diene polymer according to claim 1 or 2, wherein, the conjugated diene polymer contains a terminal-modified group.

7. A rubber composition, which contains a filler and the conjugated diene polymer according to any one of claims 1 to 6.

8. A rubber crosslinked product, which is obtained by crosslinking the rubber composition according to claim 7.

9. A tire, which contains the rubber crosslinked product according to claim 8.

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