JPH10152529A - Polymerization initiator for cyclic, conjugated and diene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a highly active polymerization initiator useful for producing a cyclic conjugated diene-based polymer. SOLUTION: This polymerization initiator is an organic lithium-based polymerization initiator for producing a cyclic conjugated diene-based polymer having polymer main chain of formula I [A to E are each a monomer unit comprising the polymer main chain arranged at random; (a) to (e) are each wt.% of components A to E respectively based on the whole weight of components A to E; A is a cyclic conjugated diene-based monomer unit, B is a linear conjugated diene-based monomer unit, C is a vinyl aromatic-based monomer unit, D is a polar monomer unit, and E is one or more kinds selected from ethylenic and α-olefinic monomer units; (a) to (e) satisfy the formulas (a+b+c+d+e)=100, 0.5<=(a)<=100, 0<=(b)<=99.5, 0<=(c)<=99.5, 0<=(d)<=99.5 and 0<=(e)<=99.5], having carbanions of one or more monomer units of the monomer units A to E, further having a chemical shift within a range of (-2.6) to 3ppm in the measurement of 7Li-NMR and used for producing a cyclic conjugated diene-based polymer of formula II [X is an agent for complex formation; Y is any of the monomer units A to E; (l), (m), (n) and (o) are each >=1].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polymerization initiator for producing a novel cyclic conjugated diene-based polymer.

[0002]

2. Description of the Related Art There have been proposed many polymerization initiators for producing a conjugated diene polymer, and some of them have been industrially used as important polymerization initiators. As typical conjugated diene polymers produced by these polymerization initiators, polybutadiene,
Homopolymers such as polyisoprene, butadiene-isoprene copolymer, styrene-butadiene copolymer, propylene-butadiene copolymer, styrene-isoprene copolymer, α-methylstyrene-butadiene copolymer, α-methylstyrene -Isoprene copolymer, acrylonitrile-butadiene copolymer, acrylonitrile-isoprene copolymer, butadiene-methyl methacrylate copolymer,
Blocks such as isoprene-methyl methacrylate copolymers, grafts, tapered or random copolymers, and even these hydrogenated polymers are known as known materials, such as plastics, elastomers, fibers, sheets, films, Machine parts, food containers, packaging materials, tires,
Belts, insulating agents, adhesives, adhesives, modifiers for other resins, etc.
It is used for various purposes and applications as needed.

For example, in the field of thermoplastic elastomers,
As a unit constituting a polymer chain, a polymer block unit having a Tg (glass transition temperature) higher than room temperature (constrained phase or hard segment) is provided at both ends, and a polymer block unit having a Tg lower than room temperature (rubber phase or Block copolymer having a polymer chain structure comprising a soft segment). Styrene-butadiene (isoprene) -styrene block copolymers and hydrogenated polymers thereof can be exemplified as typical industrial materials in this field.

A polymer blend of the styrene-butadiene (isoprene) -styrene block copolymer and its hydrogenated polymer with polystyrene, polyolefin, polyphenylene ether, styrene-butadiene diblock copolymer or its hydrogenated polymer, etc. The block copolymer composition is widely used to improve various properties of the styrene-butadiene (isoprene) -styrene block copolymer and its hydrogenated polymer, such as heat resistance, fluidity, and adhesive properties. I have. On the other hand, a large number of polymerization initiators for producing a conjugated diene polymer have been proposed so far, and play an extremely important role industrially.

[0005] In particular, in order to obtain a conjugated diene polymer having improved thermal and mechanical properties, high cis 1,
Numerous polymerization initiators that provide 4-bond content have been studied and
Is being developed. For example, lithium, an initiator system mainly containing an alkali metal compound such as sodium, or
Complex initiator systems based on transition metal compounds such as nickel, cobalt and titanium are known, and some of them are already industrially employed as polymerization initiators such as butadiene and isoprene [End . Ing. Che
m. , 48, 784 (1956), Japanese Patent Publication No. 37-819.
No. 8, publication].

On the other hand, in order to achieve a higher cis 1,4-bond content and excellent polymerization activity, rare earth metal compounds and I
Complex initiator systems comprising organometallic compounds of Group III to III metals have been studied and developed, and studies on highly stereospecific polymerization have been actively conducted [J. Polym. Sci. , Po
lym. Chem. Ed. , 18 , 3345 (198
0), Sci, Sinica. , 2/3 , 734 (19
80), Makromol. Chem. Suppl,
4 , 61 (1981), German Patent 2,848,964.
No., Rubber Chem. Technol. , 5
8 , 117 (1985)].

Among these initiator systems, it has been confirmed that a composite initiator containing a neodymium compound and an organoaluminum compound as main components has a high cis-1,4-bond content and excellent polymerization activity. It has already been industrialized as a polymerization initiator such as [Makromol. Che
m. , 94 , 119 (1981), Macromole.
cules, 15 , 230 (1982)]. However, with recent advances in industrial technology, the market requirements for polymer materials have become more and more advanced, and higher thermal (melting point, glass transition temperature, heat distortion temperature, etc.)
There has been a strong demand for the development of polymer materials having mechanical (tensile modulus, flexural modulus, etc.) characteristics.

As one of the most effective means for solving this problem, not only monomers having relatively small steric hindrance such as butadiene, isoprene and styrene, but also monomers having large steric hindrance, that is, cyclic conjugated diene Research activities to improve the polymer chain structure of conjugated diene-based polymers by homopolymerization or copolymerization of these monomers to obtain polymer materials with advanced thermal and mechanical properties It has started to be performed. However, in the prior art, butadiene,
Although an initiator system showing a somewhat satisfactory polymerization activity for a monomer having relatively small steric hindrance such as isoprene and styrene has been proposed, a monomer having large steric hindrance, that is, a cyclic conjugated diene-based monomer has been proposed. On the other hand, an initiator system having sufficiently satisfactory polymerization activity has not been found yet.

That is, in the prior art, the cyclic conjugated diene-based monomer is difficult to homopolymerize, so that not only a sufficient high molecular weight polymer cannot be obtained, but also the thermal and mechanical properties of the monomer to meet various market requirements. Even when copolymerization with another monomer is attempted for the purpose of optimization, it has been possible to obtain only a low-molecular-weight substance such as an oligomer. That is,
A method for producing an excellent cyclic conjugated diene polymer which can be sufficiently satisfied as an industrial material has not yet been known, and this solution has been strongly desired. J. Am. Chem. Soc. ,
81 , 448 (1959) discloses a cyclohexadiene homopolymer obtained by polymerizing 1,3-cyclohexadiene, which is a cyclic conjugated diene monomer, using a composite initiator consisting of titanium tetrachloride and triisobutylaluminum. A polymerization method is disclosed.

The polymerization process described here not only requires a large amount of polymerization initiator and a long reaction time,
The molecular weight of the obtained polymer is extremely low and has no industrial value. J. Polym. Sci. , Pt.
A, 2 , 3277 (1964) discloses a method for polymerizing cyclohexadiene homopolymer obtained by polymerizing 1,3-cyclohexadiene by various methods such as radical, cation, anion, and coordination polymerization. In any of the polymerization methods described herein, the molecular weight of the obtained polymer is extremely low in any case, and has no industrial value.

British Patent 1,042,625 discloses a process for polymerizing cyclohexadiene homopolymer obtained by polymerizing 1,3-cyclohexadiene using a large amount of an organolithium compound as an initiator. The polymerization method disclosed herein requires as much as 1-2% by weight of initiator based on the monomer, which is not only economically disadvantageous but also the molecular weight of the resulting polymer is extremely low. It will be something. Further, there is no suggestion or teaching as to the possibility of obtaining a copolymer. On the other hand, it is difficult to remove a large amount of initiator residue remaining in the polymer by this polymerization method, and the polymer obtained by the polymerization method has no commercial value.

J. Polym. Sci. , Pt. A,
3, the 1553 (1965), cyclohexadiene homopolymer of 1,3-cyclohexadiene was polymerized using an organic lithium compound as an initiator is disclosed. The polymer obtained here had a limit of number average molecular weight of 20,000, although the polymerization reaction was continued for 5 weeks. Polym. Prepr. (Amer. C
hem. Soc. , Div. Polym. Chem. )
12 , 402 (1971), when 1,3-cyclohexadiene is polymerized using an organolithium compound as an initiator, the limit of the number average molecular weight of cyclohexadiene homopolymer is 10,000 to 15,000. It is disclosed that the reason is that a polymerization reaction and a transfer reaction accompanied by abstraction of lithium cation and a elimination reaction (termination reaction) of lithium hydride occur simultaneously with the polymerization reaction.

[0013] Die Makromolekulare
Chemie. , 163 , 13 (1973)
A cyclohexadiene homopolymer obtained by polymerizing 1,3-cyclohexadiene using a large amount of an organolithium compound as an initiator is disclosed. The oligomeric polymer obtained here has a number average molecular weight of only 6,500. European Polymer J. et al. ,
9 , 895 (1973) describes a copolymer of 1,3-cyclohexadiene, butadiene, and isoprene using a π-allyl nickel compound as a polymerization initiator.

However, it has been reported that the polymer obtained here is a very low molecular weight oligomer and has a single glass transition temperature which indicates a random copolymer. Journal of Polymers, Vol. 34, no.
5,333 (1977) describes a copolymer of 1,3-cyclohexadiene and acrylonitrile using zinc chloride as a polymerization initiator. The alternating copolymer obtained here is an oligomer having a very low molecular weight.

US Pat. No. 4,127,710 discloses a polymer mixture obtained by polymerizing a monomer mixture of 1,3-cyclohexadiene, styrene and butadiene using a polyfunctional initiator. However, it is taught that in the polymer mixture obtained here, the yield decreases as the proportion of 1,3-cyclohexadiene in the monomer mixture increases.

US Pat. No. 4,138,536 discloses a polymer mixture obtained by polymerizing a monomer mixture of 1,3-cyclohexadiene and styrene using a polyfunctional initiator. However, in the polymer mixture obtained here, the 1,3
It is taught that the yield decreases as the proportion of cyclohexadiene increases.

J. Polym. Sci. , Polym.
Chem. Ed. , 20 , 901 (1982) have 1,
A cyclohexadiene homopolymer obtained by polymerizing 3-cyclohexadiene using an organic sodium compound as an initiator is disclosed. The organic sodium compound used here is sodium naphthalene, and a dianion formed from a radical anion is actually a polymerization starting point. That is, the number average molecular weight of the cyclohexadiene homopolymer reported here is apparently 3
8,700, but the number average molecular weight is substantially 19,3.
Only 50 molecular chains grew in two directions from the polymerization initiation point.

Further, the polymerization method disclosed herein comprises:
It is a reaction under extremely low temperature and has no industrial value. Makromol. Chem. , 191 , 2743
(1990) describes a method for polymerizing 1,3-cyclohexadiene using polystyryllithium as a polymerization initiator. In the polymerization method described here, it is taught that a transfer reaction accompanied by abstraction of lithium cation and a elimination reaction (termination reaction) of lithium hydride occur at the same time as the polymerization reaction, and polystyryllithium is used as an initiator. Despite the polymerization reaction, it was reported that at room temperature, a styrene-cyclohexadiene block copolymer was not obtained, and only a cyclohexadiene homopolymer was obtained.

Similarly, when polystyryllithium is used as an initiator and blocking is performed at -10.degree. C. or lower, a diblock copolymer of styrene-cyclohexadiene having a molecular weight of about 20,000 can be obtained in an extremely low yield. It is reported that it was obtained with. However, the copolymer obtained here has a very small content of cyclohexadiene block units. That is, in the prior art, a polymerization initiator for producing an excellent cyclic conjugated diene-based copolymer which is sufficiently satisfactory as an industrial material has not yet been known.

The present inventors have conducted various studies to solve the above problems, and as a result, have found that a specific organometallic complex (polymerization initiator)
And succeeded in producing a cyclic conjugated diene-based polymer, which has not been reported previously, by living anionic polymerization (PCT / JP94 / 00822, PCT / JP95 /
02362). However, there has been a strong demand for the development of a more active polymerization initiator for industrially efficiently producing a cyclic conjugated diene-based polymer.

[0021]

SUMMARY OF THE INVENTION The present invention provides a highly active polymerization initiator for producing a cyclic conjugated diene-based polymer.

[0022]

Means for Solving the Problems The inventors of the present invention have conducted repeated studies on the development of a highly active polymerization initiator for producing a cyclic conjugated diene-based polymer. And found the highly active organolithium-based initiator, and completed the present invention. That is, the present invention is as follows. [1] An organic lithium-based polymerization initiator for producing a cyclic conjugated diene-based polymer having a polymer main chain represented by the following formula (I), which is selected from monomer units A to E And containing a carbanion of at least one or more monomer units, and having a chemical shift in the range of -2.6 to 3 ppm in 7Li-NMR measurement, according to the following formula (II). A polymerization initiator for producing the represented cyclic conjugated diene polymer.

[0023]

Embedded image

[Formula (I) represents a composition formula of a polymer. A
To E represent the following monomer units constituting the polymer main chain;
~ E may be arranged in any order. a to e represent the respective weight percentages of the monomer units A to E with respect to the total weight of the monomer units A to E. (A): One or more monomer units selected from cyclic conjugated diene monomer units. (B): One or more monomer units selected from chain conjugated diene monomer units. (C): One or more monomer units selected from vinyl aromatic monomer units. (D): One or more monomer units selected from polar monomer units. (E): One or more monomer units selected from ethylene and α-olefin monomer units.

A to e satisfy the following relationships. a + b + c + d + e = 100, 0.5 ≦ a ≦ 100, 0 ≦ b ≦ 99.5, 0 ≦ c ≦ 99.5, 0 ≦ d ≦ 99.5, and 0 ≦ e ≦ 99.5]

[0026]

Embedded image

[2] The polymerization initiator according to [1], wherein the complexing agent X is a compound containing an element capable of coordinating with lithium and having an lone pair. The polymerization initiator according to the above [1], which is characterized in that: [3] The complexing agent X is one or more organic compounds containing an element selected from oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P). The polymerization initiator according to the above [1]. [4] The polymerization initiator according to the above [1], wherein the carbanion is at least one or more carbanions selected from monomer units A to E.

The cyclic conjugated diene-based monomer in the present invention is a cyclic conjugated diene monomer having 5 or more membered rings constituted by carbon-carbon bonds. Preferred cyclic conjugated diene monomers are 5- to 8-membered cyclic conjugated diene monomers composed of carbon-carbon bonds. Particularly preferred cyclic conjugated diene-based monomers are 6-membered cyclic conjugated diene monomers composed of carbon-carbon bonds.

Specifically, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,3-cyclooctadiene and derivatives thereof can be exemplified. Preferred cyclic conjugated diene monomers include 1,3-cyclopentadiene and 1,3-cyclohexadiene derivatives. The most preferred cyclic conjugated diene monomer is 1,3-cyclohexadiene.

The chain conjugated diene monomer in the present invention is a chain conjugated diene monomer composed of 4 to 8 carbons, specifically, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3
-Pentadiene, 1,3-hexadiene (or their derivatives) and the like. The vinyl aromatic monomer in the present invention is a vinyl aromatic monomer composed of a vinyl group and an aromatic ring, and specifically, styrene, α-methylstyrene, o-methylstyrene, p-
Methylstyrene, p-tert-butylstyrene, 1,
Examples thereof include 3-dimethylstyrene, divinylbenzene, vinylnaphthalene, vinylanthracene, 1,1-diphenylethylene, m-diisoprenylbenzene, and vinylpyridine (or derivatives thereof).

The polar monomer in the present invention is a monomer having 3 to 15 carbon atoms having a polar group such as a carbonyl group or a nitrile group, and specifically, methyl methacrylate, methyl acrylate, Polar vinyl monomers such as acrylonitrile, methyl vinyl ketone, methyl α-cyanoacrylate (or derivatives thereof), or ethylene oxide, propylene oxide, cyclohexene oxide, cyclic lactone, cyclic lactam, cyclic siloxane (or derivatives thereof), etc. Can be exemplified.

The cyclic conjugated diene-based polymer in the present invention is a polymer represented by the above formula (I), wherein at least one cyclic conjugated diene-based monomer unit is provided in a part of the main chain of the polymer. It is a polymer containing. The molecular weight (number-average molecular weight) of the cyclic conjugated diene-based copolymer in the present invention can be produced by living anionic polymerization if the polymerization initiator disclosed in the present invention is employed. Therefore, the molecular weight is arbitrarily set. And the range is not particularly limited, but generally ranges from 600 to 5,000,000.
It is set in the range of 0.

In consideration of industrial production, the number average molecular weight of the polymer chain is usually from 1,000 to 5,000,000.
And preferably in the range of 1,000 to 4,000,000, and in the range of 1,500 to 3,000,000
It is particularly preferred that the range is 2,000 to 2,000.
Most preferably, it is in the range of 000. The cyclic conjugated diene-based copolymer in the present invention may be a homopolymer composed of only a cyclic conjugated diene-based monomer, or a cyclic conjugated diene-based monomer and at least one or more monomers selected from BE. It may be a block copolymer with a monomer unit.

The organolithium initiator in the present invention is a complex compound formed by reacting a complexing agent X with an organolithium compound containing at least one or more monomeric units of carbanion active sites. Can be exemplified. The carbanion in the present invention is at least one or more carbanions selected from the monomer units A to E.

The monomer units A to E in the present invention are compounds in which the following monomers form covalent or ionic bonds with other molecules or atoms by a chemical reaction. (A): One or more monomer units selected from cyclic conjugated diene monomer units. (B): One or more monomer units selected from chain conjugated diene monomer units. (C): One or more monomer units selected from vinyl aromatic monomer units. (D): One or more monomer units selected from polar monomer units. (E): One or more monomer units selected from ethylene and α-olefin monomer units.

Specific examples of the carbanion include C _{1 to} C ₂₀ alkyl groups, C _{2 to} C ₂₀ unsaturated aliphatic hydrocarbon groups, C _{5 to} C ₂₀ aryl groups, and C _{3 to} C _20. cycloalkyl group, can be exemplified carbanion of cyclodienyl group C ₄ -C _20, more specifically,
Examples thereof include carbanions such as 1,3-cyclohexadiene, butadiene, isoprene, styrene, α-methylstyrene, and ethylene.

Particularly preferred carbanions in the present invention include cyclic conjugated diene monomer units (monomer unit A), chain conjugated diene monomer units (monomer unit B),
At least one or more carbanions selected from vinyl aromatic monomer units (monomer units C) can be exemplified. Preferred complexing agent X in the present invention is a compound containing an element having an unshared electron pair capable of coordinating to a lithium atom, for example, oxygen (O), nitrogen (N), sulfur (S), phosphorus (S). One or more organic compounds containing (P) can be exemplified.

As preferred complexing agents among these complexing agents, ether compounds, metal alkoxides, amine compounds and thioether compounds can be exemplified. Particularly preferred complexing agents are cyclic ether compounds (such as tetrahydrofuran and crown ether), metal alkoxide compounds, and amine compounds, and the most preferred complexing agents are amine compounds.

More specifically, an R ¹ R ² N— group (R ¹ , R ² is a polar group having an unshared electron pair and capable of coordinating with an organolithium compound to form a complex. An alkyl group, an aryl group, or a hydrogen atom, which may be the same or different), or an organic amine compound or an organic polymer amine compound containing one or more of these. Among these amine compounds,
Particularly preferred amine compounds are tertiary (tertiary) amine compounds, and most preferred tertiary (tertiary) amine compounds are
It is a tertiary (tertiary) diamine compound.

Specific examples of the complexing agent in the present invention include:
Diethyl ether, dibutyl ether, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 18-crown-
6, dibenzo-18-crown-6, 15-crown-
5, dibenzo-24-crown-8, cryptand, lithium-t-butoxide, potassium-t-butoxide,
Di-t-butoxybarium, porphyrin, 1,2-dipiperazinoethane, trimethylamine, triethylamine, tri-n-butylamine, quinuclidine, pyridine, 2-methylpyridine, 2,6-dimethylpyridine,
Dimethylaniline, diethylaniline, tetramethyldiaminomethane, tetramethylethylenediamine, tetramethyl-1,3-propanediamine, tetramethyl-
1,3-butanediamine, tetramethyl-1,4-butanediamine, tetramethyl-1,6-hexanediamine, tetramethyl-1,2-cyclohexanediamine,
Tetramethyl-1,4-phenylenediamine, tetramethyl-1,8-naphthalenediamine, tetramethylbenzidine, tetraethylethylenediamine, tetraethyl-1,3-propanediamine, tetramethyldiethylenetriamine, tetraethyldiethylenetriamine, pentamethyldiethylenetriamine, pentaethyldiethylenetriamine , Sparteine, diazabicyclo [2,
2,2] octane, 1,5-diazabicyclo [4,3
0] -5-nonene, 1,8-diazabicyclo [5,4,
0] -7-undecene, 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane, tetrakis (dimethylamino) ethylene, tetraethyl-2-butene-1,4-diamine, (-)-2,3
-Dimethoxy-1,4-bis (dimethylamino) butane (DBB), (+)-1- (2-pyrrolidinylmethyl)
Examples include pyrrolidine, 2,2′-bipyridyl, 4,4′-bipyridyl, 1,10-phenanthroline, hexamethylphosphoramide (HMPA), hexamethylphosphorastriamide (HMPT) and the like.

The tertiary (tertiary) amine compound which is a preferable complexing agent in the present invention includes trimethylamine, triethylamine, tri-n-butylamine, quinuclidine, pyridine, 2-methylpyridine, 2,6-dimethylpyridine, dimethyl Aniline, diethylaniline, tetramethyldiaminomethane, tetramethylethylenediamine, tetramethyl-1,3-propanediamine, tetramethyl-1,3-butanediamine, tetramethyl-1,
4-butanediamine, tetramethyl-1,6-hexanediamine, tetramethyl-1,2-cyclohexanediamine, tetramethyl-1,4-phenylenediamine, tetramethyl-1,8-naphthalenediamine, tetramethylbenzidine, tetraethyl Ethylenediamine, tetraethyl-1,3-propanediamine, tetramethyldiethylenetriamine, tetraethyldiethylenetriamine, pentamethyldiethylenetriamine, pentaethyldiethylenetriamine, sparteine, 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4 , 3,0] -5-Nonene, 1,8-diazabicyclo [5,4,0] -7-undecene, 1,4,8,1
1-tetramethyl-1,4,8,11-tetraazacyclotetradecane, tetrakis (dimethylamino) ethylene, tetraethyl-2-butene-1,4-diamine,
(-)-2,3-dimethoxy-1,4-bis (dimethylamino) butane (DBB), (+)-1- (2-pyrrolidinylmethyl) pyrrolidine, 2,2′-bipyridyl,
4,4′-bipyridyl, 1,10-phenanthroline,
Hexamethylphosphoramide (HMPA), hexamethylphosphorustriamide (HMPT) and the like can be exemplified.

In the present invention, a particularly preferred complexing agent is an aliphatic amine compound, and the most preferred amine compound is an aliphatic diamine compound. The most preferred aliphatic diamine compounds include tetramethylmethylenediamine (TMMDA) and tetraethylmethylenediamine (TE
MDA), tetramethylethylenediamine (TMED)
A), tetraethylethylenediamine (TEEDA),
Tetramethyl propylene diamine (TMPDA), tetraethyl propylene diamine (TEPDA), tetramethyl butylenediamine (TMBDA), tetraethyl butylenediamine (TEBDA), tetramethylpentanediamine, tetraethylpentanediamine, tetramethylhexanediamine (TMHDA), tetraethylhexane Diamine (TEHDA) and 1,4-diazabicyclo [2,2,2] octane (DABCO) can be exemplified.

The most preferred aliphatic diamine compound that can be industrially employed is an aliphatic diamine represented by the following formula (III) which reacts with an organolithium compound to form a stable complex compound. Those having 1 to 6 carbon atoms are preferred, and 1 to 1 carbon atoms are preferred.
Particularly preferred are those having 3 carbon atoms, and most preferred are aliphatic diamines having 2 carbon atoms.

[0044]

Embedded image

As particularly preferred complexing agents in the present invention, tetramethylethylenediamine (TMEDA),
1,4-diazabicyclo [2,2,2] octane (DA
BCO) and tetramethylethylenediamine (TMEDA) as the most preferred complexing agent. The above-mentioned complexing agent, preferably an amine compound, can be one kind or, if necessary, a mixture of two or more kinds.

Industrially preferred combinations of organolithium compounds and complexing agents for synthesizing the organolithium initiator of the present invention include poly (1,3-cyclohexadiene), polybutadiene, polyisoprene, polystyrene, polystyrene, -Number average molecular weight in terms of standard polystyrene having an anion such as α-methylstyrene or polyethylene is 5
In the range of 0 to 10,000, preferably 50 to 5,000
And particularly preferably lithium in the range of 50 to 1,000 and tetramethylmethylenediamine (TM
MDA), tetramethylethylenediamine (TMED)
A), tetramethylpropylenediamine (TMPD
A), tetramethylhexanediamine (TMHDA) and 1,4-diazabicyclo [2,2,2] octane (D
ABCO) is a combination composed of at least one complexing agent selected from ABCO).

The most preferred combination is poly (1,3
(Cyclohexadienyl) lithium, polybutadienyllithium, polyisoprenyllithium, polystyryllithium, poly-.alpha.-methylstyryllithium, polyethylenyllithium, at least one organic lithium compound and tetramethylethylenediamine. T
MEDA) and 1,4-diazabicyclo [2,2,2]
It is a combination composed of at least one amine compound selected from octane (DABCO).

The lithium cation in the present invention is exemplified by a lithium cation in a complex compound formed by reacting a complexing agent X with an organolithium compound containing at least one or more carbanion monomer units. can do. It is preferable that one to five lithium cations are contained in one molecule of the initiator, and it is particularly preferable that one or two lithium cations are contained. Further, the organolithium initiator in the present invention is not particularly limited to a dissociated state or an association state of two or more molecules.

However, the preferred association state is 2 to
8 associations, particularly preferably in the range of 2 to 6 associations. The state of the polymerization initiator of the present invention is lithium cation 7
It can be known from the chemical shift of Li-NMR. In general, it is known that the chemical shift of NMR can provide information on the electronic state of observed nuclei and the interaction with surrounding nuclides.

Regarding the polymerization initiator in the present invention, it can be interpreted that an efficient initiation reaction occurs because the ionicity of the lithium cation increases to some extent and the nucleophilicity to the monomer increases. Specifically, when the peak shifts to a low magnetic field due to a change in the electronic state of the lithium cation, the ionicity of the lithium cation decreases, and the initiation reaction with the cyclic conjugated diene-based monomer does not occur.

On the other hand, when the peak is remarkably shifted to a high magnetic field due to a change in the electronic state of the lithium cation, it can be interpreted that the ionicity of the lithium cation is increased. A transfer reaction accompanied by the extraction of lithium and a elimination reaction of lithium hydride occur to stop the reaction. That is, a preferred range of a chemical initiator for efficiently initiating the polymerization reaction of the cyclic conjugated diene-based monomer has a specific range of chemical shift.

The 7Li-NMR chemical shift in the present invention refers to the 7Li-NM of lithium cation as an initiator.
It is the chemical shift of the peak top of the main peak of the lithium cation of the initiator in methylcyclohexane at 25 ° C when the chemical shift of lithium chloride in water at 25 ° C is 0 ppm in R measurement. The atmosphere for handling the sample for NMR measurement of the polymerization initiator in the present invention is preferably an atmosphere of an inert gas such as helium, nitrogen, or argon, and is sufficiently dried and free of impurities such as oxygen and carbon dioxide. It is particularly desirable that the atmosphere be a pure inert gas atmosphere.

The NMR of the polymerization initiator according to the present invention
The measurement sample had a lithium cation concentration of 0.05.
It is desirably 0.5 mM, and is used after degassing under reduced pressure and sealing. A preferable 7Li-NMR chemical shift in the lithium cation of the polymerization initiator of the present invention is-
The chemical shift of the initiator is 2.6 to 3.0 ppm, and particularly preferred is -2.5 to 2.5 ppm, most preferably -0.5 to 1.0 ppm.

7Li-NMR on lithium cation
When the chemical shift is in a low magnetic field outside the scope of the present invention,
The ionicity of the lithium cation is reduced, the bond distance between the lithium cation and the carbanion is also reduced, and the monomer is difficult to approach, so that the polymerization initiation rate is reduced. 7Li-N
When the MR chemical shift is outside the range of the present invention and is in a high magnetic field, the ionicity of the lithium cation increases, and a transfer reaction involving the extraction of a proton at the α-position and a elimination reaction of lithium hydride occur to stop the reaction. Not preferred.

Further, in the initiator of the present invention, the lithium cation and the complexing agent contained in the initiator are each Amo.
When 1 and B mol are used, these composition ratios are appropriately selected depending on the type of the target carbanion, complexing agent, and the monomer for performing the polymerization reaction. A / B = 60/1 to 1/60, preferably A / B = 50/1 to 1/50, and A / B = 30/1 to 1/30. It is more preferable that A / B is in the range of 20/1 to 1/20, and that A / B is in the range of 10/1 to 1/10 expresses a high polymerization initiating ability. It is most preferable to do so. If the composition ratio of the lithium cation and the complexing agent is out of the range of the present invention, not only is it economically disadvantageous, but also undesirable results such as a transfer reaction and a termination reaction occur simultaneously with the polymerization reaction. become.

As a typical polymerization initiator of the present invention, lithium (Amo) having an anion such as poly (1,3-cyclohexadiene), polybutadiene, polyisoprene, polystyrene, poly-α-methylstyrene and polyethylene is used.
l, tetramethylmethylenediamine (TMMDA),
At least one complexing agent selected from tetramethylethylenediamine (TMEDA), tetramethylpropylenediamine (TMPDA), tetramethylhexanediamine (TMHDA) and 1,4-diazabicyclo [2,2,2] octane (DABCO); Especially amine compounds)
Complex compounds in which Bmol is in the range of A / B = 10/1 to 1/10 can be exemplified. Among these complex compounds, those in which A / B is in the range of 8/1 to 1/8 are further exemplified. A / B = 6/1 to 1/6 is particularly preferable, and A / B = 4/1 to 1/4 is most preferable.

The synthesis of the complex compound as the polymerization initiator of the present invention is not particularly limited, and conventionally known techniques can be applied as needed. For example, a method of dissolving an organolithium compound in an organic solvent under a dry inert gas atmosphere and adding a complexing agent solution thereto to synthesize a complex compound, or a method of dissolving an organic complexing compound in a dry inert gas atmosphere For example, a method of dissolving in a solvent and adding a solution of an organolithium compound to the solution to synthesize a complex compound can be exemplified, and it is possible to appropriately select as needed.

The above-mentioned organic solvent is preferably selected as appropriate according to the type and amount of the organolithium compound and the type and amount of the complexing agent, and is preferably used after sufficiently degassing and drying. Also,
The temperature conditions for reacting the organolithium compound with the complexing agent are also
Generally, it is possible to select a suitable time within the range of -100 to 100 ° C. Industrially, it is preferably carried out in the range of -20 to 80 ° C, and most preferably in the range of -10 to 60 ° C. Helium, nitrogen, and argon are preferable as the dry inert gas, and nitrogen or argon is preferably used industrially. As the organic solvent used for synthesizing the polymerization initiator of the present invention, a solvent which is sufficiently degassed and dried by a conventional method and which is inert to an organic lithium compound and a complexing agent is preferable.

Organic solvents that can be suitably used include butane, n-pentane, n-hexane, n-heptane and n-heptane.
Aliphatic hydrocarbon solvents such as octane, iso-octane, n-nonane, n-decane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decalin, norbornane Alicyclic hydrocarbon solvents, benzene, toluene, xylene, ethylbenzene, aromatic hydrocarbon solvents such as cumene, diethyl ether, tetrahydrofuran, ether solvents such as tetrahydropyran and the like can be exemplified. It can be selected at the same time.

These organic solvents may be used alone or, if necessary, as a mixture of two or more. Preferred organic solvents include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents. Most preferred organic solvents are aliphatic hydrocarbon solvents,
An alicyclic hydrocarbon solvent or a mixed solvent thereof.

The most preferred organic solvent employed in the synthesis of the complex compound as the polymerization initiator of the present invention is at least one kind of organic solvent selected from n-hexane, cyclohexane and methylcyclohexane, or two or more kinds of these solvents. It is a mixed solvent. The most preferable production method of the cyclic conjugated diene copolymer produced by the polymerization initiator of the present invention employs the above polymerization initiator and appropriately selects gas phase polymerization, bulk polymerization (bulk polymerization), solution polymerization, or the like. Can be implemented. As the polymerization reaction process, for example, a batch system, a semi-batch system, a continuous system, or the like can be appropriately selected and used. The polymerization reactor may be appropriately selected according to the purpose and requirements, for example, an autoclave,
Examples include a coil reactor, a tube reactor, a kneader, and an extruder.

When the method for producing the cyclic conjugated diene copolymer produced by the polymerization initiator of the present invention is solution polymerization, preferably used polymerization solvents include butane, n-pentane, n-hexane and n-hexane. Heptane, n-octane, is
Aliphatic hydrocarbon solvents such as o-octane, n-nonane and n-decane, alicyclics such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, cyclooctane, decalin, norbornane Aromatic hydrocarbon solvents, benzene, toluene, xylene, ethylbenzene, aromatic hydrocarbon solvents such as cumene, diethyl ether, tetrahydrofuran, ether solvents such as tetrahydropyran and the like can be exemplified. You can select it at any time.

These polymerization solvents may be used alone or, if necessary, in a mixture of two or more. Preferred examples of the polymerization solvent include aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents. Most preferred polymerization solvents are aliphatic hydrocarbon solvents,
An alicyclic hydrocarbon solvent or a mixed solvent thereof.

The most preferred polymerization solvent in the polymerization reaction of the present invention is at least one polymerization solvent selected from n-hexane, cyclohexane and methylcyclohexane, or a mixed solvent of two or more thereof. In the polymerization reaction of the cyclic conjugated diene-based copolymer produced by the polymerization initiator of the present invention, the amount of the polymerization initiator used is not particularly limited because it varies depending on the purpose, but is generally not limited. is in the range of ^{1 × 10 -6 mol~5 × 10 -1} mol of lithium atom relative to the monomer 1 mol, preferably ^{5 × 10 -6 mol~1 × 10 -1} mo
1 can be implemented.

The polymerization temperature in the polymerization reaction of the present invention is set to various ones as necessary, but is generally -100 to 150 ° C, preferably -80 to 120 ° C, particularly preferably -30 to 110 ° C. ° C, most preferably 0-1
It can be carried out in the range of 00 ° C. Furthermore, from an industrial viewpoint, it is preferable to carry out the polymerization reaction at room temperature to 90 ° C, most preferably at 40 to 80 ° C.

The time required for the polymerization reaction varies depending on the purpose and the polymerization conditions and cannot be particularly limited. However, it is usually within 48 hours, particularly preferably 0.5 to 24 hours. It is industrially most preferable to carry out the reaction for 1 to 10 hours. The atmosphere of the reaction system in the polymerization reaction is preferably an inert gas atmosphere such as helium, nitrogen, or argon, and is a sufficiently pure inert gas atmosphere that is sufficiently dried and contains few impurities such as oxygen and carbon dioxide. Is particularly desirable. From an industrial point of view, it is preferable to use sufficiently dried high-purity nitrogen or argon, and it is most preferable to use nitrogen.

The pressure of the polymerization reaction system may be set within the above-mentioned polymerization temperature range and within the pressure range necessary to maintain each monomer and polymerization solvent in a liquid phase, and may be appropriately set as necessary. Can do things. In the polymerization reaction of the present invention, it is necessary to maintain a state in which a polymerization catalyst and impurities that inactivate a growth (active) terminal, for example, water, oxygen, carbon dioxide gas, and the like are not mixed in the polymerization reaction system. It is preferable to obtain a copolymer. The polymerization initiator of the present invention is used industrially as an excellent polymerization initiator for producing a novel cyclic conjugated diene-based polymer, and a cyclic conjugated diene-based polymer represented by the formula (I): It can be used not only for polymerizing butadiene, isoprene, styrene and copolymers thereof, but also as a general living anionic polymerization initiator.

[0068]

The present invention will be described in more detail with reference to the following examples and comparative examples. However, the scope of the present invention is not limited by these examples. The chemicals used in the present invention are of the highest purity available,
General solvents are degassed according to the usual method, and under an inert gas atmosphere,
Refluxed and dehydrated on an active metal, and then distilled and purified were used. The 7Li-NMR measurement of the polymerization initiator is performed according to JE
The measurement was performed using an NMR measurement device (JEOLEX-270) manufactured by OL Corporation. A 1% aqueous solution of lithium chloride was used as an external standard.

The number average molecular weight (Mn) and the molecular weight distribution (Mw / Mn) of the polymer were measured using a liquid chromatograph (HLC-8020) manufactured by Tosoh Corporation and a column manufactured by Showa Denko KK. (Showdex: K805 + K8
04 + K802). P. The values in terms of standard polystyrene measured by the C (gel permeation chromatography) method are shown. The conversion (mol%) of the monomer in the polymerization reaction system was determined using a gas chromatograph (GC14A) manufactured by Shimadzu Corporation using the absolute amount of the monomer remaining in the reaction system (internal standard method). ) Was calculated. Ethylbenzene was used as an internal standard.

(Example 1) 2
The inside of the 00 ml Schlenk tube was replaced with dry argon. 6.25 ml of cyclohexane was injected into the Schlenk tube, and the temperature of the solution was kept at room temperature. A solution of s-BuLi in cyclohexane (0.7 M) was added in an amount of 3.0 mm mol in terms of lithium (Li) atoms, and then 3.1 ml of styrene was added, followed by a stirring reaction for 10 minutes. The number average molecular weight (Mn) of the obtained polystyryllithium is 500.
Met. The inside of a 100 ml pressure-resistant glass bottle which had been sufficiently dried according to another conventional method was replaced with dry argon. 20 ml of cyclohexane was poured into the pressure-resistant bottle, and the temperature of the solution was kept at room temperature under a dry argon atmosphere.

Next, the above polystyryllithium solution 1
Then, a 1.0 M solution of TMEDA in cyclohexane was added to Li / TMEDA = 4/2 (molar ratio).
After reacting at 70 ° C. for 10 minutes, the temperature was raised to 40 ° C., and a 1.0 M cyclohexane solution of TMEDA was further added to Li / TMEDA = 4/5 (molar ratio).
It was added and held so that The chemical shift of the main peak in 7Li-NMR measurement of lithium cation of this polymerization initiator was 0.4 ppm. In this solution, 1,3-cyclohexadiene (1,3-CHD)
3.6 ml was added, and a polymerization reaction was performed at 40 ° C. for 2 hours under a dry argon atmosphere.

After the completion of the polymerization reaction, the reaction was stopped by adding a methanol solution, the polymer was separated with a large excess amount of a methanol solvent, washed with methanol, dried in vacuo at 40 ° C., and the yield was 100% by weight. A white polymer was obtained. The number average molecular weight (Mn) of the obtained copolymer was 13,600, and the molecular weight distribution (Mw / Mn) was 1.29. FIG. 1 shows a GPC chart of the obtained polymer.

(Example 2) 2
The inside of the 00 ml Schlenk tube was replaced with dry argon. 6.25 ml of cyclohexane was injected into the Schlenk tube, and the temperature of the solution was kept at room temperature. A cyclohexane solution of s-BuLi (0.7 M) was added in an amount of 3.0 mm in terms of lithium atom, and then 3.1 m of styrene was added.
1 was added and the mixture was stirred and reacted for 10 minutes. The number average molecular weight (Mn) of the obtained polystyryllithium was 500.

The inside of a 100 ml pressure-resistant glass bottle which had been sufficiently dried according to another conventional method was replaced with dry argon. 20 ml of cyclohexane was poured into the pressure-resistant bottle, and the temperature of the solution was kept at room temperature under a dry argon atmosphere. Then
1 ml of the reaction solution was added, and a 0.5 M solution of 1,4-diazabicyclo [2,2,2] octane (DABCO) in cyclohexane was added to Li / DABCO = 4/2 (mo
1 ratio), reacted at 70 ° C. for 10 minutes, heated to 40 ° C., and further added a 0.5 M cyclohexane solution of DABCO to Li / DABCO = 4/5 (mol
(Ratio).

7 L of lithium cation of this polymerization initiator
The chemical shift of the main peak in i-NMR measurement was -0.5 ppm. To this solution, 3.6 ml of 1,3-cyclohexadiene (1,3-CHD) was added, and a polymerization reaction was performed at 40 ° C. for 2 hours under a dry argon atmosphere. After completion of the polymerization reaction, the reaction was stopped by adding a methanol solution, and the polymer was further separated with a large excess amount of a methanol solvent, washed with methanol, and dried in vacuo at 40 ° C.,
A white polymer was obtained with a yield of 100% by weight. The number average molecular weight (Mn) of the obtained copolymer was 13,000, and the molecular weight distribution (Mw / Mn) was 1.14.

(Example 3) 2
The inside of the 00 ml Schlenk tube was replaced with dry argon. 6.25 ml of cyclohexane was injected into the Schlenk tube, and the temperature of the solution was kept at room temperature. A cyclohexane solution of s-BuLi (0.7 M) was added in an amount of 3.0 mm in terms of lithium atom, and then 3.1 m of styrene was added.
1 was added and the mixture was stirred and reacted for 10 minutes. The number average molecular weight (Mn) of the obtained polystyryllithium was 500.

The inside of a 100 ml pressure-resistant glass bottle which had been sufficiently dried according to another conventional method was replaced with dry argon. 20 ml of cyclohexane was poured into the pressure-resistant bottle, and the temperature of the solution was kept at room temperature under a dry argon atmosphere. Then
1 ml of the above polystyryllithium solution was added,
A 1.0 M solution of TMHDA in cyclohexane was added to Li /
Added so that TMMDA = 4/2 (molar ratio),
After reacting at 70 ° C for 10 minutes, the temperature was raised to 40 ° C, and T
A 1.0 M solution of MHDA in cyclohexane was added to Li / T
It was added and held so that MHDA = 4/5 (molar ratio).

7 L of lithium cation of the polymerization initiator
The chemical shift of the main peak in i-NMR measurement was -2.4 ppm. To this solution, 3.6 ml of 1,3-cyclohexadiene (1,3-CHD) was added, and a polymerization reaction was performed at 40 ° C. for 2 hours under a dry argon atmosphere. After completion of the polymerization reaction, the reaction was stopped by adding a methanol solution, and the polymer was further separated with a large excess amount of a methanol solvent, washed with methanol, and dried in vacuo at 40 ° C.,
A white polymer was obtained with a yield of 98% by weight. The number average molecular weight (Mn) of the obtained copolymer was 19,600, and the molecular weight distribution (Mw / Mn) was 1.27.

(Comparative Example 1) 2
The inside of the 00 ml Schlenk tube was replaced with dry argon. 6.25 ml of cyclohexane was injected into the Schlenk tube, and the temperature of the solution was kept at room temperature. A cyclohexane solution of s-BuLi (0.7 M) was added in an amount of 3.0 mm in terms of lithium atom, and then 3.1 m of styrene was added.
1 was added and the mixture was stirred and reacted for 10 minutes. The number average molecular weight (Mn) of the obtained polystyryllithium was 500.

The inside of a 100 ml pressure-resistant glass bottle which had been sufficiently dried according to another conventional method was replaced with dry argon. 20 ml of cyclohexane was poured into the pressure-resistant bottle, and the temperature of the solution was kept at room temperature under a dry argon atmosphere. Then
1 ml of the above polystyryllithium solution was added,
A 1.0 M solution of triethylamine in cyclohexane is
Li / triethylamine = 4/2 (molar ratio), and the mixture was reacted at 70 ° C. for 10 minutes, heated to 40 ° C., and further added a 1.0 M solution of triethylamine in cyclohexane to Li / triethylamine = 4 (mol ratio). / 5 (mol
(Ratio).

7 L of lithium cation of the polymerization initiator
The chemical shift of the main peak in i-NMR measurement was -2.7 ppm. To this solution, 3.6 ml of 1,3-cyclohexadiene (1,3-CHD) was added, and a polymerization reaction was performed at 40 ° C. for 2 hours under a dry argon atmosphere. After completion of the polymerization reaction, the reaction was stopped by adding a methanol solution, and the polymer was further separated with a large excess amount of a methanol solvent, washed with methanol, and dried in vacuo at 40 ° C.,
A white polymer was obtained with a yield of 23% by weight. The number average molecular weight (Mn) of the obtained copolymer was 5,400, and the molecular weight distribution (Mw / Mn) was 1.44.

(Example 4) 2
The inside of the 00 ml Schlenk tube was replaced with dry argon. 20 ml of cyclohexane was injected into the Schlenk tube, and the temperature of the solution was kept at room temperature. n- of n-BuLi
A hexane solution (1.7 M) was added in an amount of 0.4 mm in terms of lithium atom, and then 1.0 M-
The cyclohexane solution was converted to Li / TMEDA = 4/2 (m
ol ratio). After reacting at 70 ° C for 10 minutes, the temperature was raised to 40 ° C, and 1.0M
-The cyclohexane solution was prepared using Li / TMEDA = 4/5
(Mol ratio). afterwards,
0.2 g of 1,3-cyclohexadiene was added and reacted with stirring for 1 hour.

The number average molecular weight (Mn) of the obtained polycyclohexadienyl lithium was 500. The chemical shift of the main peak in 7Li-NMR measurement of lithium cation of this polymerization initiator was 0.6 ppm. FIG. 2 shows a 7Li-NMR spectrum chart of the obtained polymerization initiator. To this solution, 2.5 g of 1,3-cyclohexadiene (1,3-CHD) was added, and a polymerization reaction was performed at 40 ° C. for 1 hour under a dry argon atmosphere.
After the completion of the polymerization reaction, the reaction was stopped by adding a methanol solution, the polymer was further separated with a large excess amount of a methanol solvent, washed with methanol, and dried in vacuo at 40 ° C. to give a yield of 1
A white polymer was obtained at 00% by weight. The number average molecular weight (Mn) of the obtained CHD homopolymer is 6,000,
The molecular weight distribution (Mw / Mn) was 1.44.

[0084]

The polymerization initiator of the present invention has a desired electronic state for efficiently initiating the polymerization reaction of the cyclic conjugated diene-based monomer. It has excellent initiator efficiency in the polymerization of diene polymers. Further, the molecular weight distribution of the obtained polymer is narrow, and the molecular weight can be arbitrarily controlled, so that the polymer is industrially used in a wide range. Further, the polymer obtained by the polymerization initiator of the present invention contains a cyclic conjugated diene-based monomer unit exhibiting thermal and mechanical properties in a polymer chain. Since the monomer unit can contain a cyclohexene ring and a cyclohexane ring, which are the most stable 6-membered ring structures as cyclic organic compounds, high-performance plastics can be used as excellent industrial materials (structural materials or functional materials). , Transparent impact-resistant plastic, special elastomer, thermoplastic elastomer, elastic fiber, sheet, film, tube, hose, optical material, sealing agent, elastic adhesive, general adhesive, adhesive, sealant, elastic paint, general Paints, coatings, insulating agents, lubricants, plasticizers, separation membranes, permselective membranes, microporous membranes, functional membranes, vibration and sound insulation materials, vibration and sound insulation materials, functional films ( Electric films, photosensitive films, etc.), functional beads (molecular sieves, polymer catalysts, polymer catalyst bases, etc.), automotive parts, electric parts, aerospace parts, railway parts, marine parts, electronic parts, battery parts , Electronics-related parts, multimedia-related parts, plastic battery materials, solar cell parts, functional fibers,
Functional sheets, mechanical parts, building materials and civil engineering parts, medical equipment parts, pharmaceutical packaging materials, sustained-release packaging materials, pharmacological substance supporting substrates,
Not only is it used as a print base material, food container, general packaging material, clothing, sports and leisure goods, general miscellaneous goods, tires, belts, other resin modifiers, etc.
Thermosetting resin by blending a crosslinking agent as needed,
It can be used as a curable resin such as an ultraviolet curable resin, an electron beam curable resin, and a wet curable resin.

[Brief description of the drawings]

FIG. 1 is a GPC chart of a polymer obtained in Example 1.

FIG. 2 shows 7Li of a polymerization initiator obtained in Example 4.
FIG. 4 is an NMR spectrum chart.

Claims (4)

[Claims] An organic lithium-based polymerization initiator for producing a cyclic conjugated diene-based polymer having a polymer main chain represented by the following formula (I), which is selected from monomer units A to E: Contains at least one or more monomeric unit carbanions, and in 7Li-NMR measurement,
A polymerization initiator for producing a cyclic conjugated diene-based polymer represented by the following formula (II), wherein the chemical shift is in the range of -2.6 to 3 ppm. Embedded image [Formula (I) represents a composition formula of a polymer. A to E represent the following monomer units constituting the polymer main chain, and A to E may be arranged in any order. a to e are monomer units A to
The respective weight percentages of the monomer units A to E with respect to the total weight of E are shown. (A): One or more monomer units selected from cyclic conjugated diene monomer units. (B): One or more monomer units selected from chain conjugated diene monomer units. (C): One or more monomer units selected from vinyl aromatic monomer units. (D): One or more monomer units selected from polar monomer units. (E): One or more monomer units selected from ethylene and α-olefin monomer units. ae
Satisfies the following relationship: a + b + c + d + e = 100, 0.5 ≦ a ≦ 100, 0 ≦ b ≦ 99.5, 0 ≦ c ≦ 99.5, 0 ≦ d ≦ 99.5, and 0 ≦ e ≦ 99.5] 2. The polymerization initiator according to claim 1, wherein the complexing agent X is a compound containing an element capable of coordinating with lithium and having an unshared electron pair. The polymerization initiator according to claim 1, wherein 3. The complexing agent X containing an element selected from oxygen (O), nitrogen (N), sulfur (S) and phosphorus (P).
The polymerization initiator according to claim 1, wherein the polymerization initiator is at least one kind or two or more kinds of organic compounds. 4. The polymerization initiator according to claim 1, wherein the carbanion is at least one or more carbanions selected from monomer units A to E.