JPH0920839A - Rubber for improved tire tread - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber composition not damaging wet skid properties, processability, etc., having extremely excellent performances of modulus, tensile strength, impact resilience, low heat generation and wear resistance, suitably useful as a tire tread. SOLUTION: This rubber for improved tire tread is obtained by blending 100 pts.wt. of a raw material rubber containing at least 10wt.% of a rubber-like polymer, which is a conjugated diolefin polymer or a copolymer of a conjugated diolefin and a vinyl aromatic compound, contains specific terminal modified groups at both the ends of the polymer, has <=2.2 molecular weight distribution (Mw/Mn) of the polymer or the copolymer and 15-150 Mooney viscosity (ML1+4 <100> deg.C), in a rubber component with 10-100 pts.wt. of carbon black, 5-100 pts.wt. of a process oil, 0.3-5 pts.wt. of sulfur and a vulcanization promoter.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composition of a conjugated diolefin polymer or copolymer produced by using an alkyllithium catalyst, which is suitable for a tread of a heat-saving tire.

[0002]

2. Description of the Related Art In recent years, due to the soaring price of crude oil, energy saving has been advocated in various fields of industry, and many attempts have been made to reduce the consumption of gasoline in automobiles as well. The weight of tires is being reduced, and the air resistance of the vehicle body and rolling resistance of tires are being reduced.

Among these energy-saving attempts related to automobiles, various attempts have been made as a method for reducing rolling resistance of automobile tires. For example, a method for improving a tire structure and a tire tread are used. Examples of such improvements include vulcanized rubber.

In an attempt to reduce rolling resistance of these tires, a method for improving vulcanized rubber, that is, a method for reducing energy loss of vulcanized rubber to improve impact resilience or exothermicity, has been proposed. , Methods of improving the raw rubber used for vulcanized rubber, changing the type of carbon black, and reducing the amount of carbon black or oil used for vulcanized rubber to achieve high impact resilience are being studied. .

Among the above-mentioned methods of improvement, as a method of improving the raw material rubber, it is possible to use a polymer having a higher molecular weight than the conventional one, based on the findings on the physical properties of the raw material rubber and the vulcanized rubber up to now. Although the impact resilience can be improved, it cannot be greatly improved because the Mooney viscosity of the rubber and the compound increases and the processability decreases. On the other hand, even in the method of changing the blending formula to reduce the blending amount of oil and carbon black, the Mooney viscosity of the blend is increased, and in this case, the processability is deteriorated, and the processability is sacrificed in any method. It is difficult to improve without doing so.

By the way, in recent years, it has been found that a random styrene-butadiene copolymer rubber having many vinyl bonds and having a branched structure can be suitably used for tire applications, rubbers having various structures have been studied, and various proposals have been made. There is. For example, when a styrene-butadiene copolymer rubber having an increased vinyl content is tin-coupled to form a branched styrene-butadiene copolymer rubber, rolling resistance is improved by adding butadiene immediately before the coupling reaction and polymerizing. A method has been proposed (JP-A-57-8740).
No. 7, JP-A-58-162605). However, even with this method, the rolling resistance cannot be said to be sufficiently improved, and there is a problem that the manufacturing method becomes complicated.

Also, a monomer prepared by continuously introducing a monomer into a polymerization zone having a high stirring efficiency controlled at a temperature of 80 ° C. or higher by a catalyst composed of an organolithium compound and a Lewis base to allow the polymerization to proceed. A random styrene-butadiene copolymer rubber has been proposed (Japanese Patent Laid-Open No. Sho 5).
7-100112). This polymer exhibited excellent properties such as tensile strength, impact resilience, low heat build-up, abrasion resistance, and wet skid resistance. However, this copolymer rubber also needs to be further improved in terms of impact resilience and low heat buildup.

In addition to the above, various methods for introducing functional groups into the ends of the polymer have been proposed as methods for improving the raw rubber. For example, one in which a benzophenone having a substituent at the end of the living polymer is reacted (JP-A-58)
-162604, JP-A-58-189203), at the end of the living polymer

[0009]

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A compound having a bond or the like is reacted (JP-A-60-137913, JP-A-60-13).
No. 7914), but the impact resilience, low heat generation,
In some cases, considerable improvement in wear resistance etc. was observed, but the improvement was insufficient.

There is also a proposal to obtain a conjugated diene-based polymer having a tertiary amino group introduced at one end of the polymer using lithium amide as an initiator, and then to perform branched coupling with a coupling agent (Japanese Patent Application Laid-Open No. 2000-242242). Sho 59-382
No. 09), since lithium amide is used as an initiator, there is a problem that the initiation of polymerization is not uniform, the molecular weight distribution is abnormally expanded, or the polymerization is difficult to proceed and a high molecular weight polymer is difficult to obtain. Improvements in impact resilience, low heat build-up, abrasion resistance, etc. were insufficient.

Further, there is a proposal of a method of introducing an anion-polymerizable monomer having a tertiary amino group as a functional group into a polymer chain of 1 to 30 wt% (Japanese Patent Laid-Open No. 154742/1983). Low heat buildup and abrasion resistance have never been improved.

Further, there is a proposal (Japanese Patent Publication No. 44-855) to carry out polymerization with lithium naphthalene or sodium naphthalene as an initiator and then to modify both terminals by reacting with organic sulfenyl chloride. Since the catalyst was incomplete, the molecular weight distribution was extremely widened, and only one end was connected to the living room, so impact resilience, low heat buildup, and abrasion resistance were not improved.

[0014]

Therefore, as the problems to be solved by the present invention, wet skid properties, workability, etc. are not impaired, and modulus, tensile strength, impact resilience, low heat buildup, and abrasion resistance are extremely high. As a result of intensive studies to develop a rubber composition having excellent performance, the inventors have invented a specific conjugated diolefin polymer or copolymer composition.

[0015]

Means for Solving the Problems That is, the present invention provides a conjugated diolefin polymer or a copolymer of a conjugated diolefin and a vinyl aromatic compound, wherein both ends of the polymer are group IV of the periodic table. , Group V and Group VI, and the electronegativity is represented by the formula 0.41 ≦ Xp / N ≦ 0.60 (where Xp is the electronegativity of the atom and N is the periodic table of the atom). No.), the molecular weight distribution (Mw / Mn) of the polymer or copolymer is 2.2 or less. Carbon black 10 to 100 parts by weight of a raw rubber containing at least 10% by weight of a rubber-like polymer having a Mooney viscosity (ML _{1 + 4} ¹⁰⁰ ° C.) of 15 to 150 in a rubber component.
100 parts by weight, process oil 5 to 100 parts by weight, sulfur 0.
Provided is a rubber composition for a tire tread, which comprises 3 to 5 parts by weight and a vulcanization accelerator.

The present invention will be described in detail below. A rubber-like conjugated diolefin polymer having terminal modifying groups at both ends of the present invention or a copolymer of a conjugated diolefin and a vinyl aromatic compound (hereinafter referred to as a conjugated diolefin-based polymer).
Is a rubber-like conjugated diolefin-based polymer of a living room having a modifying group at one end after preliminarily reacting an alkylmonolithium with a specific vinyl compound in a hydrocarbon solvent and then polymerizing or copolymerizing a conjugated diolefin-based monomer. As a combination, a method in which a specific vinyl compound is reacted again to introduce a modifying group at both terminals, and a living rubbery conjugated diolefin polymer having a modifying group at one terminal is reacted with a coupling agent A method of introducing a modifying group at the terminal, and the living rubber-like conjugated diolefin polymer having a modifying group at one terminal has a specific atomic group in the molecule and a functional group that bonds to the active lithium terminal. It can be obtained by a method of reacting a compound provided with and introducing a modifying group at both ends, and a combination or combination of the above methods.

Further, a conjugated diolefin-based monomer is polymerized by using a dilithium catalyst in a hydrocarbon solvent to obtain a rubber-like conjugated diolefin-based polymer containing living lithium at both ends, which is reacted with a specific vinyl compound. A method of introducing a modifying group at the terminal, or having a specific modifying group in the above-mentioned living lithium-containing rubber-like conjugated diolefin polymer containing both ends, and having a functional group that bonds to the living terminal and a function that bonds to the living terminal. It can be obtained by a method of reacting a compound having a group to introduce a modified group at both ends, and a combination or combination thereof.

The conjugated diolefin used in the present invention includes 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-methyl-1,3-butadiene,
1,3-hexadiene and the like are included, preferably 1,3
-Butadiene, isoprene. The vinyl aromatic compound used in the present invention includes styrene, α-methylstyrene, vinyltoluene, vinylnaphthalene, divinylbenzene, trivinylbenzene, divinylnaphthalene, and the like, and preferably styrene.

The terminal modifying group to be introduced into both ends of the polymer of the present invention is selected from Group IV, Group V and Group VI of the periodic table, and has electronegativity of the formula 0.41≤Xp / N ≦ 0.
It has an atomic group containing at least one atom contained in the range of 60 (in the formula, Xp represents the electronegativity of the atom, and N represents the periodic table group number of the atom). Where X
p is the electronegativity of the atom, and Pauling's electronegativity (Chemical Handbook, Basic Edition, Second Edition, page 1288, published by Maruzen Co., Ltd.) is used in the present invention. N is a group number in the periodic table of the atom. Atoms that satisfy such requirements include nitrogen, oxygen, silicon, phosphorus, sulfur, germanium,
There are tin and lead. As the atomic group containing at least one of these atoms, as a nitrogen-containing atomic group,

[0020]

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As the oxygen-containing atomic group,

[0022]

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As the sulfur-containing atomic group,

[0024]

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As the phosphorus-containing atomic group,

[0026]

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As the silicon-, germanium-, tin-, and lead-containing atomic groups, -MX ₃ , -MX ₂ R ₁ , -MX (R ₁ ) ₂ , -M (R ₁ )
₃ (M is any one of Si, Ge, Sn and Pb, X is halogen, R ₁ is a substituent such as alkyl and aryl) and the like. These atomic groups may be adjacent to each other, or 2
One or more may be present in the same terminal modifying group.

Of these, particularly preferred atomic groups are:

[0029]

[Chemical 6]

## EQU1 ##

The specific vinyl compound for introducing the terminal modifying group of the present invention into the conjugated diolefin polymer is a vinyl compound having the above-mentioned atomic group, and among these, particularly, a tertiary amino group-containing vinyl compound. Compounds are preferred.

As the tertiary amino group-containing vinyl compound,
General formula

[0033]

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, The general formula

[0035]

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And a compound selected from vinyl pyridine derivatives, such as p-dimethylaminostyrene,
p-diethylaminostyrene, p-dimethylaminomethylstyrene, p- (2-dimethylaminoethyl) styrene, m- (2-dimethylaminoethyl) styrene, p-
(2-diethylaminoethyl) styrene, p- (2-dimethylaminovinyl) styrene, p- (2-diethylaminovinyl) styrene, 2-vinylpyridine, 4-vinylpyridine, 2-vinyl-5-ethylpyridine and the like. . P- (2-dimethylaminoethyl) styrene is preferably used.

When the active lithium terminal is reacted with these specific vinyl compounds to introduce a terminal modifying group, an average of 10 mol or less, preferably 6 mol or less, more preferably 1 to 4 mol of the terminal modifying group per one terminal is introduced. Introduce. If the number of the terminal-modified groups is more than this, the exothermicity and impact resilience are inferior, and if the number of the terminal groups is less, the exothermicity and impact resilience effects are reduced.

In the compound having a specific atomic group for introducing the terminal modifying group of the present invention into the conjugated diolefin polymer and having a functional group capable of binding to the active lithium terminal, the specific atomic group is It is selected from Group IV, Group V and Group VI of the Periodic Table and has an electronegativity of the formula 0.41 ≦ Xp.
/N≦0.60 (in the formula, Xp represents the electronegativity of the atom, and N represents the periodic group number of the atom), and represents an atomic group containing at least one atom, and the activity The functional group bonded to the lithium terminal is

[0039]

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It is a functional group selected from the following. Of these, particularly compounds having a tertiary amino group and a carbonyl group or a thiocarbonyl group in the molecule, carbodiimides of the general formula (R ₁ ) _l (R ₂ ) _m SnX (R ₁ and R ₂ are alkyl, aryl and alkoxy) Group, X is halogen, l
+ M = 3, l = 0 or an integer of 1 to 3, m = 0 or 1 to 3
A compound having a thioether group and a carbonyl or thiocarbonyl group.

The compound having a tertiary amino group and a carbonyl group or a thiocarbonyl group in the molecule is represented by the general formula

[0042]

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[0043] (M is O or S, R _1, R ₂ is alkyl of C ₁ ~ _18, arylalkyl, aryl group) compounds having the general formula

[0044]

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(M is O or S, an integer of m = 1 to 3,
Alkyl of R _1, R ₂ is C ₁ ~ _18, arylalkyl,
Compounds having an aryl group), general formula

[0046]

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(M is O or S, n = 0 to 6 is an integer,
Alkyl of R _1, R ₂ is C ₁ ~ _18, arylalkyl,
Compounds having an aryl group), general formula

[0048]

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(M is O or S, an integer of m = 1 to 3,
Alkyl of R _1, R ₂ is C ₁ ~ _18, arylalkyl,
Compounds having an aryl group), general formula

[0050]

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(M is O or S, m is an integer of 1 to 3,
Alkyl of R _1, R ₂ is C ₁ ~ _18, arylalkyl,
Compounds having an aryl group), general formula

[0052]

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(M is O or S, R ₃ is an atomic group containing a tertiary amino group, a pyridyl group, a quinolyl group and the like).

These are, for example, N, N-dimethylformamide, N, N-diethylformamide, N, N-
Dimethylacetamide, N, N-diethylacetamide, N, N-dimethyl-N ', N'-dimethylaminoacetamide, N, N-dimethylacrylamide, N, N
-Dimethylmethacrylamide, N, N-dimethylpropioamide, N, N-dimethylbenzamide, N, N-dimethyl-N ', N'-(p-dimethylamino) benzamide, N, N-dimethylthioformamide, N , N,
N ', N'-tetramethylurea, N, N, N', N'-
Tetramethylthiourea, N, N'-dimethylethyleneurea, N-ethyl-N-methyl-8-quinolinecarboxamide, N, N-dimethylnicotinamide, N, N-dimethyl-4-pyridylamide, N, N- Dimethylmethacrylamide, N-methyl-ε-caprolactam, N-methyl-δ-valerolactam, N-methyl-γ-butyrolactam, N-methyl-β-propiolactam, N, N,
N ′, N′-tetramethylmaleic acid amide, N, N,
N ', N'-tetramethylphthalamide, N-methylsuccinimide, N-methylphthalimide, 10-acetylphenoxazine, 3,7-bis (diethylamino) -1
0-benzoylphenoxazine, 10-acetylphenothiazine, 3,7-bis (dimethylamino) -10-benzoylphenothiazine, ethyl N, N-diethylcarbamate, N, N-dimethyl-N ' , N '-(p-diethylamino) benzalacetamide, N, N-dimethyl-N', N '-(p-dimethylamino) cinnamylideneacetamide, N, N-dimethyl-N', N '-(2 −
Dimethylamino) vinylamide, p-dimethylaminobenzophenone, 4,4'-bis (dimethylamino) benzophenone, 4,4'-bis (diethylamino) benzophenone, p-dimethylaminobenzaldehyde, p-
Dimethylaminoacetophenone, p- (2-dimethylaminoethyl) acetophenone, 4,4'-bis (2-diethylaminoethyl) benzophenone, 4,4'-bis (3-dimethylaminopropyl) benzophenone, p-
(2-Dimethylaminoethyl) benzaldehyde, 4,
4'-bis (2-dimethylaminovinyl) benzophenone, p- (2-dimethylaminovinyl) acetophenone, p-dimethylaminobenzalacetone, p-diethylaminobenzalacetone, p-dimethylaminobenzalacetophenone, N, N -(P-Dimethylamino) cinnamoyl-N ', N'-(p-dimethylamino) benzene, N, N- (p-dimethylamino) cinnamoyl-
N ', N'-(2-dimethylamino) ethylene, 1,3
-Bis (4'-dimethylaminobenzal) acetone,
2,6-bis (4'-dimethylaminobenzal) cyclohexanone, p-dimethylaminocinnamylideneacetone, p-diethylaminocinnamylideneacetophenone, 4- (p-dimethylaminophenyl) -1,3-butadienyl-N ', N'-(p'-dimethylamino) phenyl ketone, 3,3-bis (p-dimethylaminophenyl) phthalide, 3-diethylamino-6-methylfluorane, 3-diethylamino-6-methyl-7-ani Rinofluorane, 3,6-bis (diethylamino) fluorane-γ-anilinolactam, 2- (p-pyridyl) vinylmethylketone, 2- [4 ′-(2 ′, 6′-dimethyl) pyridyl] vinylmethyl Ketone, 2- (p-pyridyl) vinyl-N ', N'-(p'-dimethylamino) phenyl ketone, 2- (o-pyridyl Vinyl methyl ketone, 4-acetylpyridine, 2-acetylpyridine, 4
-Benzoylpyridine, 2-benzoylpyridine, 4-
(P'-Dimethylaminobenzoyl) pyridine, methyl 4-pyridinecarboxylate, methyl 2-pyridinecarboxylate, 4,4'-dipyridyl ketone, N, N, N ', N'
-Tetramethyl thiuram monosulfide, N, N,
N ', N'-tetrabutyl thiuram disulfide, N,
Examples include N, N ′, N′-pentamethylene thiuram tetrasulfide.

As carbodiimides, general formula -N =
A compound having a C = N-bond, which is a compound including a dialkylcarbodiimide, an alkylarylcarbodiimide, and a diarylcarbodiimide, and examples thereof include dimethylcarbodiimide, diethylcarbodiimide, dipropylcarbodiimide, dibutylcarbodiimide, dihexylcarbodiimide, dicyclohexylcarbodiimide, dibenzylcarbodiimide, and Examples include diphenylcarbodiimide, methylpropylcarbodiimide, butylcyclohexylcarbodiimide, ethylbenzylcarbodiimide, propylphenylcarbodiimide, and phenylbenzylcarbodiimide.

Examples of the tin compound represented by the general formula (R ₁ ) _l (R ₂ ) _m SnX include trimethyltin chloride, triethyltin chloride, tributyltin chloride, tribenzyltin chloride, triphenyltin chloride,
Examples include tritolyltin chloride, methyldibutyltin chloride, phenyldimethyltin chloride, butyldiphenyltin chloride, benzyldiphenyltin chloride.

Examples of the compound having a thioether group and a carbonyl or thiocarbonyl group include thiodipropionic acid ester, alkylthiopropionic acid ester and dialkyldixanthogen compound. Examples thereof include distearyl thiodipropionic acid and myristyl thiodipropionic acid. , Dilauryl thiodipropionate, ethyl lauryl thiopropionate, diisopropyl dixanthate, diethyl dixanthate and the like.

When reacting the active lithium terminal with a compound having a specific atomic group and a functional group that bonds to the active lithium terminal, the compound is used in an amount of 0.5 mol or more, preferably with respect to the active lithium. 0.65-1.2
Used in moles.

As the coupling agent, tin, silicon,
Examples thereof include germanium polyhalogen compounds, polyvinyl compounds, polyallyl compounds, polyphenyl compounds, polybenzyl compounds, and polyalkoxy compounds, such as tin tetrachloride, silicon tetrachloride, germanium tetrachloride,
4 tin bromide, 4 silicon bromide, 3 methyl tin chloride, 3 ethyl tin chloride, 3 butyl tin chloride, 3 methyl methyl chloride,
There are dimethyltin dichloride, dibutyltin dichloride, dimethylsilicon dichloride, tetravinyltin, butyltrivinyltin, tetraallyltin, tetraphenyltin, triphenyltin chloride, tetrabenzyltin, tetraphenoxysilicon, tetramethoxysilicon and the like. Preference is given to using tin tetrachloride, methyltin trichloride, dibutyltin dichloride.

These coupling agents are used in an amount of 0.5 equivalent or more based on the living end, and preferably 0.65 to
Used at 1.2 equivalents. In addition, these methods of introducing a modifying group at the end of the living polymer can be combined and used in combination. In that case, as in the case of reacting with a specific vinyl compound, the case where the living terminal is still present after the reaction, the case where the coupling agent is reacted, or the molecule has a specific atomic group, and is bonded to the active lithium terminal There is a case where the living end is stopped after the reaction as in the case of reacting with a compound having a functional group. In the case of these combinations, in short, the modifying group is effectively 1 mol or more per one end and the average. It is important to react so as to bond 10 moles or less for the effect of impact resilience and exothermicity, and it is practically not to leave the unreacted compound as much as possible, and in view of cost, tensile strength, modulus, hardness It is also necessary in terms of performance.

The hydrocarbon solvent used in the present invention includes n-butane, n-pentane, iso-pentane and n-butane.
Hexane, n-heptane, iso-octane, cyclohexane, methylcyclopentane, benzene, toluene and the like, and particularly preferable solvents are n-hexane, n-heptane and cyclohexane. This hydrocarbon solvent may be used alone or in combination of two or more, and it is usually used in an amount of 1 to 20 parts by weight per 1 part by weight of the monomer.

The alkylmonolithium catalyst is a hydrocarbon having one lithium atom bonded, such as ethyllithium, propyllithium, n-butyllithium,
sec-Butyllithium, tert-butyllithium, phenyllithium, propenyllithium, hexyllithium and the like, particularly preferably n-butyllithium, sec
-Butyllithium. This alkylmonolithium catalyst can be used not only as one type but also as a mixture of two or more types. The amount of the alkylmonolithium catalyst used depends on the Mooney viscosity of the produced polymer, but is usually 0.3 to 3 mmol, preferably 0.5 to 1.5 mmol per 100 g of the monomer.

As the dilithium catalyst used in the present invention, three types are known, depending on the production method. That is, by the reaction of metallic lithium and a dihalogen compound, by the reaction of metallic lithium and diolefins, and by the reaction of organic lithium with a disubstituted vinyl group- or alkenyl group-containing aromatic hydrocarbon. In any case, it is necessary that the dilithium catalyst has a small amount of monolithium portion, preferably the purity of the dilithium catalyst component is 90 mol% or more, and the initiation rates of both lithium atoms are substantially the same as the dilithium catalyst. is there. In this respect, a dilithium catalyst obtained by reacting an organolithium with a disubstituted vinyl group- or alkenyl group-containing aromatic hydrocarbon is preferable.

More preferably, JP-A-58-136603
This is the method according to the publication. The amount of dilithium catalyst used is
Depending on the Mooney viscosity of the polymer produced, usually 10
The amount is 0.4 to 6 mmol, preferably 0.8 to 3 mmol per 0 g.

In the conjugated diolefin rubber of the present invention, the vinyl aromatic compound is used in an amount of 0 to 50% by weight in the monomer, and if it exceeds 50% by weight, the vulcanized rubber is inferior in heat generation.
On the other hand, if the vinyl aromatic compound content is low, the tensile strength of the vulcanized rubber will be low, preferably 5 to 45% by weight.

The vinyl bond in the conjugated diolefin portion of the conjugated diolefin rubber used in the present invention is preferably 10 to 75%, more preferably 15 to 50%. When the vinyl bond is low, the wet skid resistance is low, while when the vinyl bond is high, the abrasion resistance is low.

The molecular weight distribution of the conjugated diolefin rubber used in the present invention is calculated by using GPC using a calibration curve of standard polystyrene, and the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is calculated. The size (Mw / Mn) of the molecular weight distribution represented by 2.2 is 2.2 or less, preferably 1.2 to 2.0, and more preferably 1.3 to 2.0.
1.8. When the molecular weight distribution is larger than 2.2, the impact resilience and heat generation are poor, and when the molecular weight distribution is small, the processability is deteriorated.

The molecular weight distribution by GPC may be one peak or two peaks. Usually, the workability can be improved by coupling with a branching agent having 3 or more branches.

When the conjugated diolefin rubber used in the present invention is a copolymer of a conjugated diolefin and a vinyl aromatic, a random copolymer is preferable. If necessary, a Lewis base can also be used as a randomizing agent. Examples of the randomizing agent include ethers such as tetrahydrofuran, diethylene glycol dimethyl ether and diethylene glycol dibutyl ether, amines such as triethylamine and tetramethylethylenediamine, thioethers, phosphines, phosphoramides, alkylbenzene sulfonates, alkoxides of potassium and sodium, and the like. Can be mentioned.

The vinyl aromatic chain distribution, which is a measure of the randomness of the copolymer of conjugated diolefin and vinyl aromatic compound, is analyzed by GPC of low temperature ozonolysis products of the copolymer rubber. This method was developed by Tanaka et al., And the chain distribution of vinyl aromatic compounds is analyzed by GPC, which is a decomposition product obtained by ozone cleavage of all double bonds of conjugated diolefins ( Macromolecules, 1983,1
6, 1925).

The copolymer used in the present invention is an isolated vinyl aromatic compound analyzed by this method, that is, a vinyl aromatic compound having one chain of vinyl aromatic compound units is 40% of all vinyl aromatic compounds. It is preferably not less than 50% by weight, more preferably not less than 50% by weight, and a long-chain vinyl aromatic compound block, that is, a vinyl aromatic compound having 8 or more chains of vinyl aromatic compound units is 5% by weight of all vinyl aromatic compounds. The following is preferable, and 2.5% by weight or less is more preferable. Whether the isolated vinyl aromatic compound is less than 40% by weight or the long chain vinyl aromatic compound block is more than 5% by weight, the excellent properties of the composition of the present invention are high impact resilience and low elasticity. The balance between heat generation and high wet skid resistance is lowered, which is not preferable.

The Mooney viscosity (ML) of the rubber-like conjugated diolefin polymer having modifying groups at both ends of the present invention is
_{1 + 4} ¹⁰⁰ ° C.) is preferably 15 to 150, more preferably 20 to 130. If the Mooney viscosity is lower than this, the vulcanized rubber will have poor tensile strength, wear resistance, impact resilience, and heat buildup.If the Mooney viscosity is higher than this, it will have poor processability, and excessive torque will be generated during kneading with rolls or Banbury. The performance of the vulcanized rubber is inferior due to aging or poor carbon dispersion.

The specific conjugated diolefin rubber having modifying groups at both ends of the present invention may be used alone or as a blend with another rubber. When used by blending with other rubber, the conjugated diolefin-based rubber having modifying groups at both specific ends of the present invention is used in an amount of 10% by weight or more based on the raw rubber. If it is less than 10% by weight, the balance between high impact resilience, low heat buildup and high wet skid resistance, which are excellent properties of the composition of the present invention, is deteriorated.

Other rubbers to be used together with the conjugated diolefin-based rubber having modifying groups at both specific ends of the present invention include natural rubber, synthetic cis polyisoprene, styrene-
Various diene rubbers vulcanized by sulfur such as butadiene copolymer rubber and polybutadiene rubber are included.

The composition of the present invention, in which the conjugated diolefin rubber having modifying groups at both ends is used alone or in a blend with another rubber, is suitable for a tire tread comprising carbon black, a vulcanizing agent and a vulcanization accelerator. It becomes a thing.

The amount of carbon black used to prepare the specific conjugated diolefin-based rubber composition of the present invention is 10 to 100 parts by weight of carbon black based on 100 parts by weight of the raw rubber. If it is less than 10 parts by weight, the tensile strength, abrasion resistance, etc. are not sufficient, and if it exceeds 100 parts by weight, the rubber elasticity is remarkably lowered, which is not preferable. It is preferably 20 to 80 parts by weight.

The type of carbon black used in the preparation of the specific conjugated diolefin rubber composition of the present invention is preferably iodine adsorption amount (IA) of 60 mg / g or more and dibutyl phthalate oil absorption amount (DBP) of 80 ml.
/ 100 g or more of carbon black is used. Such carbon black is a carbon black having a small particle size and a high structure, and if it is other than this, the high tensile strength, high impact resilience and wear resistance of the present invention may not be obtained in a high balance. IA is preferably 80 mg / g
The carbon black has a DBP of 100 ml / 1.00 g or more. Examples of these carbon blacks include those called HAF, ISAF, and SAF.

In the preparation of the specific conjugated diene rubber composition of the present invention, 0.3 to 5 parts by weight of sulfur is used as a vulcanizing agent with respect to 100 parts by weight of the raw rubber. When the amount of sulfur is small, tensile strength, impact resilience, and abrasion resistance are insufficient, and when it is too large, rubber elasticity decreases. Preferably it is 0.5 to 2.5 parts by weight.

In the preparation of the specific conjugated diene rubber composition of the present invention, various conventionally known vulcanization accelerators may be used as the vulcanization accelerator, but thiazole vulcanization accelerators are preferable. Is used. What is a thiazole vulcanization accelerator?

[0080]

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It is a vulcanization accelerator having a basic structure of. Although these vulcanization accelerators provide the excellent tensile strength, impact resilience, and abrasion resistance of the present invention, other vulcanization accelerators may not provide proper vulcanization. These vulcanization accelerators are preferably vulcanization accelerators M (2-mercaptobenzothiazole), vulcanization accelerators DM (dibenzothiazyl disulfide), vulcanization accelerators CZ (N-cyclohexyl-). Two
-Benzothiazyl sulfenamide). The amount of vulcanization accelerator used is preferably 0.2 to 3 parts per 100 parts of rubber.

In the composition using the specific conjugated diene rubber of the present invention, those which are usually used as a process oil for compounding rubber are used according to the purpose and application.
Depending on its chemical structure, it is divided into paraffin-based, naphthene-based, and aromatic-based types. Aromatic-based types are used in applications where importance is placed on tensile strength and wear resistance, and naphthene-based and paraffin-based types are further used in applications where emphasis is placed on impact resilience and low-temperature properties. Is preferably used. The amount is preferably 5 to 100 parts by weight with respect to 100 parts by weight of the raw rubber. If it is less than 5 parts by weight, the workability is poor and the dispersion of carbon black is poor, so that the performance such as tensile strength and elongation is exhibited. No, on the other hand 100
If it exceeds the weight part, the tensile strength, impact resilience and hardness are remarkably lowered, which is not preferable.

When used, the composition of the specific conjugated diene rubber according to the present invention may further contain a filler other than carbon black, zinc oxide, stearic acid, an antioxidant, an antiozonant and a wax. Etc. can be added.

Fillers other than carbon black include silicic acid, silicates, calcium carbonate, titanium oxide,
Various clays are used.

The composition of the copolymer rubber of the present invention is obtained by kneading the above-mentioned components by a known mixer for the rubber industry, such as an open roll or an internal mixer, by a known method. The rubber product obtained by the vulcanization step exhibits excellent performance as compared with rubber products obtained from conventionally known rubber compositions. Above all, it exhibits particularly high impact resilience, low heat build-up, tensile strength, and wet skidability. Therefore, the composition of a usual conjugated diolefin polymer or a conjugated diolefin-vinyl aromatic compound copolymer is used, and it is particularly preferably used for a tread of a tire.

[0086]

EXAMPLES Examples will be shown below, but these show the present invention more specifically and do not limit the scope of the present invention.

[0087]

Example 1 Into a glass bottle with a rubber stopper having an inner volume of 300 ml replaced with nitrogen, was added 50 ml of cyclohexane containing 0.52 g of n-butyllithium, and 3.55 g of p- (2-dimethyl) was stirred at room temperature. Aminoethyl) styrene (2.5 mol per Li) was gradually injected over about 15 minutes, and the mixture was reacted by stirring at room temperature for 1 hour.

A reactor equipped with a stirrer having an internal volume of 10 l was charged with 4598 g of cyclohexane, 780 g of purified butadiene, 162 g of purified styrene, and 38 g of tetrahydrofuran, and the temperature was kept at 40 ° C., and then n-butyllithium and p were previously adjusted. The reaction product of-(2-dimethylaminoethyl) styrene was injected to initiate the polymerization, and thereafter the polymerization temperature was raised adiabatically. From the time when the internal temperature reached 75 ° C., a mixture of 138 g of butadiene and 322 g of cyclohexane was added over 10 minutes using a metering pump, and 1 minute after the addition was completed, 3.55 g of p- (2-dimethyl) was added. Aminoethyl) styrene (2.5 mol per Li) was added and the reaction was continued for another 20 minutes. Then, after adding 8 g of BHT (2,6-di-t-butyl-4-methylphenol) as an antioxidant to the polymer solution, the solvent was removed by heating and the polymer was recovered.

The obtained polymer has a Mooney viscosity (ML
_{1 + 4} ¹⁰⁰ ° C.) 25, styrene content 15% by weight, microstructure of butadiene part is 1,4-trans bond 32
%, 1,4 cis bond 22%, 1,2-vinyl bond 46%
It was. In addition, the molecular weight distribution Mw / M of this polymer determined by GPC (gel permeation chromatography)
n = 1.3, which indicated that the GPC curve had one peak.

The styrene content and the microstructure of the butadiene portion were determined by measuring the IR spectrum and calculating by the method of Hampton. Mw / Mn is based on G.M. P. C.
(Shimadzu, LC-3A, column 10 ^4, 10 ^5, 1
0 ^6, one each, the solvent, tetrahydrofuran, detector:
Differential refractometer) and calculated by a method using a calibration curve with polystyrene as a standard substance.

The isolated styrene determined by GPC of the ozonolysis product was 68% by weight, and the long-chain block styrene was 0.3% by weight, based on the total styrene.

Then, using this polymer as a raw material rubber and using the composition shown in Table 1 and a test Banbury mixer having an internal capacity of 1.7 l, the method B of the standard compounding mixing procedure of ASTM-D-3403-75 was used. According to the above, a compounded product was obtained, and these were vulcanized, and each physical property was measured. The measurement was performed by the method shown below.

(1) Hardness, tensile strength; JIS-K-63
Followed 01. (2) Impact resilience; the Ryupke method according to JIS-K-6301, but the impact resilience at 70 ° C. is measured by preheating the sample in an oven at 70 ° C. for 1 hour and then quickly taking it out.

(3) Guddleitch heat generation Using a Guddleitch flexometer, a load of 48 pounds, a displacement of 0.225 inch, a start of 50 ° C., and a rotation speed of 1
The test was carried out under the condition of 800 rpm, and the temperature rise difference after 20 minutes was expressed.

(4) Wet skid resistance Stanley London portable skid tester is used, and a safety walk (3M) is used as the road surface.
Was measured according to the method of ASTM-E-808-74. It was indicated by an index with the measured value of SBR1502 being 100. The measurement results are shown in Table 2.

[0096]

Example 2 As in Example 1, after obtaining a living copolymer rubber having a modifying group bonded to one end, 0.927 g was used instead of p- (2-dimethylaminoethyl) styrene.
N, N'-dimethylethylene urea (1 mol per Li) was added and the polymer was recovered in the same manner. The polymer obtained has a Mooney viscosity of 28, a styrene content of 15% by weight,
The microstructure of the butadiene portion was 33% 1,4-trans bond, 22% 1,4-cis bond and 45% 1,2-vinyl bond. Further, Mw / Mn = 1.4, and G
The curve for PC indicated a single peak. The isolated styrene obtained from GPC of the ozone decomposed product was 65% by weight based on the total styrene, and the long-chain block styrene was 0.1%.
It was 5% by weight. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0097]

Example 3 After obtaining a living copolymer rubber in which a modifying group is bonded to one end in the same manner as in Example 1, 0.159 g was obtained.
Tin tetrachloride (0.3 equivalents to Li) was added, and after 1 minute, 1.53 g of 4,4′-bis (dimethylamino) was added.
Benzophenone (0.7 mol per Li) was added and the polymer was similarly recovered. The polymer obtained has a Mooney viscosity of 55, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bonds of 32% and 1,4-
The cis bond was 21% and the 1,2-vinyl bond was 47%.
Further, Mw / Mn = 1.6, indicating that the GPC curve has two peaks. In addition, the isolated styrene obtained by GPC of the ozone decomposition product is 68% by weight based on the total styrene.
And long-chain block styrene was 0.5% by weight. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0098]

Example 4 A dilithium catalyst was prepared by the method of Example 1 of JP-A-58-136603.

[0099]

Embedded image

Was prepared.

In a reactor equipped with a stirrer having an internal volume of 10 l, 4598 g of cyclohexane, 780 g of purified butadiene, 162 g of purified styrene and 38 g of tetrahydrofuran were charged, the temperature was kept at 40 ° C., and then the cyclohexane solution of the dilithium catalyst prepared above was added. Dilithium catalyst 2.32
Polymerization was initiated by injecting an amount equivalent to g, and thereafter the polymerization temperature was adiabatically raised. 1 when the internal temperature reaches 75 ° C
A mixture of 38 g of butadiene and 322 g of cyclohexane was added over 10 minutes using a metering pump, and 1 minute after the end of the addition, 2.07 g of N-methyl-ε-caprolactam (1.0 mol per Li) was added. In addition, the mixture was further reacted for 20 minutes. Then, after adding 8 g of BHT as an antioxidant to the polymer solution, the solvent was removed by heating and the polymer was recovered. The obtained polymer had a Mooney viscosity of 30, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bonds of 32% and 1,4-cis bonds of 2.
2% and 1,2-vinyl bond 46%. Also, Mw
/Mn=1.3, and the GPC curve indicated that there was one peak. Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Example 1
Compounding and vulcanization were performed in the same manner as in, and the performance was measured. The results are shown in Table 2.

[0102]

[Example 5] In the same manner as in Example 4, a living copolymer rubber at both ends was obtained with a dilithium catalyst, and N-methyl-ε-
4.36 g of 4,4'-bis (dimethylamino) benzophenone (1.0 per Li) instead of caprolactam
Mol) was added and the polymer was similarly recovered. The obtained polymer had a Mooney viscosity of 32, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bond 32%, 1,4-cis bond 21%, and 1,2-vinyl bond 47. It was in%. In addition, Mw / Mn = 1.3, indicating that the GPC curve has one peak. Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0103]

Example 6 In the same manner as in Example 4, a living copolymer rubber at both ends was obtained with a dilithium catalyst, and N-methyl-ε-
Instead of caprolactam, 7.10 g of p- (2-dimethylaminoethyl) styrene (2.5 mol per Li) was added, and the polymer was similarly recovered. The polymer obtained has a Mooney viscosity of 35, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bond 32.
%, 1,4-cis bond 21%, 1,2-vinyl bond 47
%. In addition, Mw / Mn = 1.4, GPC
Curve indicated that there was one mountain. Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0104]

Example 7 In the same manner as in Example 4, a living copolymer rubber at both ends was obtained with a dilithium catalyst, and N-methyl-ε-
Instead of caprolactam, 3.35 g of N, N'-cyclohexylcarbodiimide (1.0 mol per Li) was added, and the polymer was similarly recovered. The obtained polymer had a Mooney viscosity of 32, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bond of 32%.
The content was 1,4-cis bond 21% and 1,2-vinyl bond 47%. In addition, Mw / Mn = 1.3, indicating that the GPC curve has one peak. In addition, the isolated styrene obtained from GPC of the ozone decomposition product is 6 with respect to the total styrene.
5% by weight, 0.5% by weight of long-chain block styrene
It was. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0105]

[Example 8] In the same manner as in Example 4, a living copolymer rubber at both ends was obtained with a dilithium catalyst, and N-methyl-ε-
Instead of caprolactam, 4.26 g of 4-vinylpyridine (2.5 mol per Li) was added and the polymer was recovered in the same manner. The obtained polymer has a Mooney viscosity of 37, a styrene content of 15% by weight, and a microstructure of a butadiene portion having a 1,4-trans bond of 32% and a 1,4-cis bond of 2.
1% and 1,2-vinyl bond 47%. Also, Mw
/Mn=1.4, indicating that the GPC curve had one peak. Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Example 1
Compounding and vulcanization were performed in the same manner as in, and the performance was measured. The results are shown in Table 2.

[0106]

[Example 9] In the same manner as in Example 4, a living copolymer rubber at both ends was obtained with a dilithium catalyst, and N-methyl-ε-
Instead of caprolactam, 6.25 g of triphenyltin chloride (1.0 mol per Li) was added, and the polymer was similarly recovered. The polymer obtained has a Mooney viscosity of 3
7. The styrene content was 15% by weight, and the microstructure of the butadiene portion was 1,4-trans bond 32%, 1,4-cis bond 21%, and 1,2-vinyl bond 47%. Further, Mw / Mn = 1.4, indicating that the GPC curve has one peak. Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene.
Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0107]

[Example 10] In the same manner as in Example 4, a dilithium catalyst was used to obtain a living copolymer rubber at both ends, and N-methyl-ε was obtained.
Instead of caprolactam, 4.90 g of ethyl lauryl thiopropionate (1.0 mol per Li) were added and the polymer likewise recovered. The obtained polymer has a Mooney viscosity of 38, a styrene content of 15% by weight, and a microstructure of the butadiene portion is 1,4-trans bond 32%, 1,4.
-Cis bond was 21% and 1,2-vinyl bond was 47%. Further, Mw / Mn = 1.4, indicating that the GPC curve has one peak. GP of ozone decomposition products
The isolated styrene determined from C was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0108]

Example 11 In the same manner as in Example 4, a dilithium catalyst was used to obtain a living copolymer rubber at both ends, and N-methyl-ε was obtained.
-3.38 g of N, N, N ', instead of caprolactam,
N′-Tetramethylthiuram monosulfide (1.0 mol per Li) was added and the polymer was similarly recovered. The polymer obtained has a Mooney viscosity of 36 and a styrene content of 1
5% by weight, the microstructure of the butadiene part is 1,4-trans bond 32%, 1,4-cis bond 21%, 1,2-
The vinyl bond was 47%. Also, Mw / Mn = 1.3
And the GPC curve indicated that there was one peak.
Further, the isolated styrene determined by GPC of the ozone decomposition product was 65% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Formulated as in Example 1,
It was vulcanized and the performance was measured. The results are shown in Table 2.

[0109]

Comparative Example 1 A reactor equipped with a stirrer having an internal volume of 10 l was charged with 4598 g of cyclohexane, 780 g of purified butadiene, 162 g of purified styrene and 38 g of tetrahydrofuran, and the temperature was kept at 40 ° C., and then 0.52 g of n-butyllithium was added. Was injected to start the polymerization, and thereafter the polymerization temperature was raised adiabatically. From the time when the internal temperature reached 75 ° C., a mixture of 138 g of butadiene and 322 g of cyclohexane was added over a period of 10 minutes by using a metering pump, and after the addition was completed, the mixture was reacted for 10 minutes and then oxidized into a polymer solution. After adding 8 g of BHT as an inhibitor, the solvent was removed by heating and the polymer was recovered. The obtained polymer had a Mooney viscosity of 22, a styrene content of 15% by weight, and a butadiene portion having a microstructure of 1,4-trans bond of 34%.
The content was 1,4-cis bond 23% and 1,2-vinyl bond 43%. In addition, Mw / Mn was 1.1, indicating that the GPC curve had one peak. In addition, the isolated styrene obtained from GPC of ozone decomposition products is 5 for all styrene.
1% by weight, long-chain block styrene is 1.3% by weight
It was. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0110]

Comparative Example 2 After obtaining a living polymer in the same manner as in Comparative Example 1, 3.55 g of p- (2-dimethylaminoethyl) styrene (2.5 mol per Li) was added and the reaction was continued for 20 minutes. Then, the polymer was recovered in the same manner. The obtained polymer had a Mooney viscosity of 30, a styrene content of 15% by weight, and a microstructure of a butadiene portion having a 1,4-trans bond of 32%, a 1,4-cis bond of 21% and a 1,2-vinyl bond of 47. It was in%. In addition, Mw / Mn = 1.3, indicating that the GPC curve has one peak. The isolated styrene determined by GPC of the ozone decomposed product was 63% by weight, and the long-chain block styrene was 0.5% by weight, based on the total styrene. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0111]

Comparative Example 3 After obtaining a living polymer in the same manner as in Comparative Example 2, 2.18 g of 4,4′-bis (dimethylamino) benzophenone (per Li was used instead of p- (2-dimethylaminoethyl) styrene. 1 mol) was added and the polymer was similarly recovered. The obtained polymer has a Mooney viscosity of 28,
The styrene content was 15% by weight, and the microstructure of the butadiene part was 1,4-trans bond 32%, 1,4-cis bond 22%, and 1,2-vinyl bond 46%. Also, M
The w / Mn was 1.2, and the GPC curve indicated that there was one peak. Further, the isolated styrene obtained by GPC of the ozone decomposition product was 65% by weight based on the total styrene,
The long-chain block styrene was 0.3% by weight. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results are shown in Table 2.

[0112]

Comparative Example 4 Emulsion-polymerized SBR-1502 was compounded and vulcanized in the same manner as in Example 1 and the performance was measured. Table 2 shows the results
Shown in

[0113]

Comparative Example 5 A reactor equipped with a stirrer having an internal volume of 10 l was charged with 4920 g of cyclohexane, 908 g of purified butadiene, 162 g of purified styrene and 25 g of tetrahydrofuran, and then 4.32 g of lithium morpholinide was injected to initiate polymerization. Then, polymerization was carried out at 60 ° C. for 1 hour. Five minutes after the addition of 10 g of butadiene, 0.378 g of tin tetrachloride was added and the reaction was continued for another 30 minutes. Then, the polymer was recovered in the same manner as in Comparative Example 1. The obtained polymer had a Mooney viscosity of 50, a styrene content of 15% by weight, a microstructure of a butadiene portion of 1,4-trans bond of 35%,
The content was 1,4-cis bond 22% and 1,2-vinyl bond 43%. In addition, Mw / Mn = 2.7, and the GPC curve showed a polymodal shape. The isolated styrene determined by GPC of the ozone decomposed product was 50% by weight, and the long-chain block styrene was 6.5% by weight, based on the total styrene. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results were as follows.

Formulation Mooney viscosity: 78 Hardness (Hs): 62 300% Modulus (kg / cm): 108 Tb (kg / cm): 215 El (%): 470 Lupke impact resilience [23 ° C]: 52 Lupke Impact resilience [70 ° C.]: 63 Heat generation 50 ° C. ΔT ° C .: 34 Wet skid resistance (index): 98

[0115]

Comparative Example 6 In the same manner as in Example 1, a reaction product of n-butyllithium and p- (2-dimethylaminoethyl) styrene was prepared. [10-fold scale] Two reactors with a stirrer having an internal volume of 10 liters and an L / D (ratio of length to width) of 4 were connected in series, and purified butadiene and purified styrene (85/15 weight ratio). Then, cyclohexane was used as a solvent, tetrahydrofuran was used as a vinylating agent, and the n-butyllithium reaction product prepared above was used as a catalyst at a rate of 0.42 g per 100 g of monomer (phm) for continuous polymerization. The monomer was a 22% by weight cyclohexane solution, and the butadiene solution was divided into a ratio of 1: 2: 7.
Position 2/3 of the vertical length from the bottom of the reactor, 1
From the / 3 position and the bottom position, and all other substances from the bottom were metered in so that the average residence time was 45 minutes. Moreover, the polymerization temperature of the first group was controlled with a jacket so as to be 110 ° C.

Next, this polymer solution was continuously introduced into the second group, and in the second group, p- (2-dimethylaminoethyl) styrene was added at a ratio (phm) of 0.36 g per 100 g of the polymer. It was added continuously and reacted at 80 ° C.
Then, BHT was added to the polymer solution, the solvent was removed by heating, and the polymer was recovered. The obtained polymer had a Mooney viscosity of 23, a styrene content of 15% by weight, and a microstructure of the butadiene portion of 1,4-trans bond of 33%,
22% of 4-cis bond and 45% of 1,2-vinyl bond. In addition, Mw / Mn = 2.4, and the GPC curve had one peak but was broad. In addition, the isolated styrene obtained by GPC of the ozone decomposed product is 6 with respect to the total styrene.
3% by weight, long-chain block styrene is 0.3% by weight
It was. Compounding and vulcanization were performed in the same manner as in Example 1, and the performance was measured. The results were as follows.

Formulation Mooney viscosity: 74 Hardness (Hs): 62 300% Modulus (kg / cm): 110 Tb (kg / cm): 220 El (%): 480 Lupke impact resilience [23 ° C]: 53 Lupke Impact resilience [70 ° C]: 65 Exothermic 50 ° C ΔT ° C: 33 Wet skid resistance (index): 100

[0118]

[Table 1]

[0119]

[Table 2]

[0120]

As described above, the conjugated diolefin rubber according to the present invention has extremely good tensile strength, impact resilience and exothermicity. The composition of the present invention is particularly suitable for tire tread applications and has great industrial significance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C08K 3/06 KCU C08K 3/06 KCU 5/01 KCZ 5/01 KCZ

Claims (1)

[Claims] 1. A conjugated diolefin polymer or a copolymer of a conjugated diolefin and a vinyl aromatic compound, wherein both ends of the polymer are group IV, group V and group VI of the periodic table.
Selected from the group and having electronegativity of the formula 0.41 ≦ Xp / N
A terminal modifying group having an atomic group containing at least one atom contained in the range of ≦ 0.60 (wherein Xp represents the electronegativity of the atom, and N represents the periodic group number of the atom). And the molecular weight distribution (Mw / Mn) of the polymer or copolymer is 2.2 or less, and the Mooney viscosity (ML _{1 + 4} ¹⁰⁰ ° C.) is 1
10 to 100 parts by weight of carbon black, 5 to 100 parts by weight of process oil, and 0.3 to 5 of sulfur based on 100 parts by weight of a raw rubber containing at least 10% by weight of a rubbery polymer of 5 to 150 in a rubber component. A rubber composition for a tire tread, which comprises a part by weight and a vulcanization accelerator.