JP2595541B2 - Method for producing novel conjugated diene polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a lanthanide-based rare earth metal catalyst that is polymerized with a conjugated diene, and the polymer immediately after the polymerization is reacted with a specific halogen compound. The present invention relates to a method for producing a novel conjugated diene polymer having excellent wear properties and mechanical properties.

[Conventional technology]

In recent years, durability and long life have been increasingly demanded as rubber members, and it has become important to improve rubber properties such as abrasion resistance, mechanical properties, and low heat generation.

Conventionally, polybutadiene, which is a rubbery polymer obtained by using a catalyst containing nickel, cobalt, titanium or the like as a main component, has poor abrasion resistance.

On the other hand, as a rubber-like polymer having excellent abrasion resistance, polybutadiene produced by a lanthanum series rare earth metal catalyst is known, and among them, the present inventors have disclosed JP-A-58-5741.
The polybutadiene produced using the lanthanum series rare earth metal catalyst proposed in Japanese Patent Publication No. 0 is particularly excellent in abrasion resistance.

Japanese Patent Application Laid-Open No. 60-40109 discloses a process for improving processability by reacting a polybutadiene produced with a lanthanum series rare earth metal catalyst with tetrahalomethane or a specific organoaluminum compound. It is stated that an improved polybutadiene can be obtained.

[Problems to be solved by the invention]

However, with these known polybutadienes,
The abrasion resistance is still insufficient.

The present invention has been made in view of the above-mentioned conventional technical problems, and an object of the present invention is to provide a conjugated diene polymer which simultaneously satisfies abrasion resistance, mechanical properties, and low heat generation.

[Means for solving the problem]

That is, the present invention relates to (a) a lanthanum series rare earth element compound and (b) a general formula AlR ¹ R ² R ³ (where R ¹ , R ²
And R ³ are the same or different and each has a hydrogen atom or carbon number 1
To 8 hydrocarbon groups, all of which are not hydrogen atoms), optionally in the presence of a catalyst containing (c) a Lewis acid and / or (d) a Lewis base. The conjugated diene is polymerized in an inert organic solvent, and then (b) a compound of the general formula (X represents a halogen atom) and / or a halogenated isocyano compound having A novel conjugated diene-based polymer characterized by reacting an acid halide having X is the same as described above (hereinafter, the above-mentioned halogenated isocyano compound and acid halide are collectively referred to as "halogen compound"). Is provided.

The present invention, when obtaining a conjugated diene-based polymer such as polybutadiene, by reacting a specific halogen compound to the polymer immediately after polymerization by the lanthanum series rare earth metal catalyst system, abrasion resistance, low heat generation, mechanical It is a further improvement of various characteristics such as the characteristic characteristics.

Lanthanum series rare earth metal catalyst used in the present invention,
(A) a lanthanum series rare earth metal compound (hereinafter referred to as “component (a)”); and (b) an organoaluminum compound represented by the general formula AlR ¹ R ² R ³ (hereinafter referred to as “component (b)”).
Catalyst system. The catalyst system may optionally contain (c) the Lewis acid (hereinafter referred to as “component (c)”) and / or the (d) Lewis base (hereinafter referred to as “component (d)”).
).

First, as the lanthanum series rare earth element compound is a component (a), a compound represented by the general formula LNY _'3 is preferably used. Here, Ln is an atomic number of 57 to
71 is a lanthanum series rare earth element, among which cerium, lanthanum, praseodymium, neodymium and gadolinium are preferred, and neodymium is particularly preferred because it is easily available industrially.

These rare earth elements may be a mixture of two or more kinds.

Y 'is in the form of an alkyl, an alkoxide, a thioalkoxide, an amide, a phosphate, a phosphite, a halogen or a carboxylate, and particularly preferably an alkoxide, a halide or a carboxylate.

Among them, the alkyl type compounds of the lanthanum series rare earth element is represented by LnR _3, as the R include benzyl group, a phenyl group, butyl group, a hydrocarbon group having 1 to 20 carbon atoms, such as cyclopentadienyl group be able to.

The alcohol-type compound (alkoxide) is represented by the general formula Ln (OR) ₃ (wherein Ln and R are the same as described above), and preferred alcohols are 2-ethyl-hexyl alcohol, oleyl alcohol, stearyl alcohol, and phenol. And benzyl alcohol.

The thioalcohol type compound (thioalkoxide) is represented by the general formula Ln (SR) ₃ (wherein Ln and R are the same as described above), and preferable thioalcohols include thiophenol.

The amide type compound (amide) is represented by the general formula Ln (N
R ₂ ) ₃ (wherein Ln and R are as defined above), and preferred amines include dihexylamine and dioctylamine.

As the phosphate of the rare earth element, a general formula (Wherein Ln and R are the same as described above), and preferably include tris (dihexyl phosphate) neodymium and tris (diphenyl phosphate) neodymium.

As the phosphite of the rare earth element, a general formula (Wherein Ln and R are the same as described above), and preferably include tris (dihexyl phosphite) neodymium and tris [di (2-ethylhexyl) phosphite] neodymium.

The halogen-type compound is represented by the general formula LnX ₃ (where Ln is the same as above, X is the same as above and represents a halogen atom), and the halogen atom is preferably a chlorine atom, a bromine atom, or an iodine atom. It is.

As the carboxylate of the rare earth element, a general formula (RC
OO) ₃ Ln, wherein R is a hydrocarbon group having 1 to 20 carbon atoms, preferably a saturated or unsaturated alkyl group, and a linear, branched or cyclic, carboxyl group Is bonded to a primary, secondary or tertiary carbon atom. Examples of specifically preferred carboxylic acids include octanoic acid, 2-ethyl-hexanoic acid, oleic acid, stearic acid, benzoic acid, and naphthenic acid.

Specific examples of these components (a) include, for example, neodymium trichloride, dymium trichloride (neodymium 72% by weight, lanthanum 20
Mixture of rare earth metal trichloride of 8% by weight of praseodymium), 2-ethylhexanoic acid / neodymium, 2-ethylhexanoic acid / didim, naphthenic acid / neodymium, 2,2
-Diethylhexanoic acid / neodymium, neodymium trimethacrylate, neodymium trimethacrylate polymer and the like.

The organoaluminum compound as the component (b) has the general formula AlR ¹ R ² R ³ (where R ¹ , R ² and R ³ are the same or different and are a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms). Are not all hydrogen atoms), specifically, trimethylaluminum, triethylaluminum, triisopropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum, tricyclohexylaluminum, diisobutylaluminum hydride, Examples thereof include diethylaluminum hydride, dipropylaluminum hydride, ethylaluminum dihydride, propylaluminum dihydride, and isobutylaluminum dihydride.

As the Lewis acid as the component (c), for example, a general formula Al
An aluminum halide compound represented by R ⁴ _m X _3-m (wherein R ⁴ is a hydrocarbon group having 1 to 8 carbon atoms, m is an integer of 0 to 3 and X is the same as described above), a halogen element, and And halides such as tin and titanium.

Among them, particularly preferred are dimethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, methylaluminum sesquichloride, ethylaluminum sesquibromide, ethylaluminum dichloride, and bromides and iodide compounds thereof.

Examples of the Lewis base as the component (d) include acetylacetone, tetrahydrofuran, pyridine, N, N-dimethylformamide, thiophene, diphenyl ether, triethylamine, organic phosphorus compounds, and monohydric or dihydric alcohols.

The composition of the lanthanum series rare earth metal catalyst used in the present invention is usually as follows.

Component (b) / component (a) (molar ratio) is from 10 to 150, preferably from 15 to 100. If it is less than 10, the polymerization activity is low,
On the other hand, if it exceeds 150, the effect on polymerization activity is small, and it is economically disadvantageous.

Component (c) / component (a) (molar ratio) is 0 to
6, preferably from 0.5 to 5.0, and if it exceeds 6, the polymerization activity will be low.

Further, component (d) / component (a) (molar ratio) is 0 to
It is preferably 20 to 1, more preferably 1 to 15. If it exceeds 20, the polymerization activity is undesirably low.

As the catalyst component, (a), (b), (c),
In addition to the component (d), if necessary, a conjugated diene is added to the component (a).
It may be used in a proportion of 0 to 50 mol per 1 mol of the lanthanide series rare earth element compound as a component. The conjugated diene used for catalyst preparation is the same isoprene as the monomer for polymerization,
1,3-butadiene, 1,3-pentadiene and the like are used. Although a conjugated diene as a catalyst component is not essential, the combined use thereof further improves the catalytic activity of the catalyst component.

To prepare the catalyst, for example, (a)-
(D) reacting a component and, if necessary, a conjugated diene. At that time, the order of addition of each component may be arbitrary. These components are mixed and reacted in advance,
Aging is preferred from the viewpoint of improving the polymerization activity and shortening the period of inducing polymerization initiation, but the components of the catalyst may be added directly to the solvent and the monomer during the polymerization.

FIG. 1 shows an example of a method for preparing the catalyst used in the present invention. As is clear from FIG. 1, the lanthanum series rare earth metal catalyst used in the present invention comprises (A) a transition metal component (a) a lanthanum series rare earth element compound,
It comprises (B) an aluminum compound which is an organometallic component, and (C) a third component which is (c) a Lewis acid and / or (d) a Lewis base.
The order of adding the component (d) is not particularly limited.
In this catalyst preparation, the component (a) is preferably brought into contact with the component (d), but the order of addition of the other components is not particularly limited.

The polymerization solvent is an inert organic solvent, for example, aromatic hydrocarbon solvents such as benzene, toluene, xylene, n-pentane, n-hexane, n-butane, aliphatic hydrocarbon solvents such as cyclohexane, methyl Alicyclic hydrocarbon solvents such as cyclopentane and cyclohexane,
Halogenated hydrocarbon solvents such as ethylene dichloride and chlorobenzene and mixtures thereof can be used.

The polymerization temperature is usually -20 ° C to 150 ° C, preferably 30 ° C.
~ 120 ° C. The polymerization reaction may be a batch type or a continuous type.

The monomer concentration in the solvent is usually 5 to 50% by weight,
Preferably it is 10 to 35% by weight.

In addition, in order to not deactivate the lanthanum series rare earth metal catalyst and the polymer of the present invention for producing the polymer, mixing of a compound having a deactivating effect such as oxygen, water, or carbon dioxide gas in the polymerization system is minimized. Careful consideration is required.

The conjugated diene that can be polymerized by the catalyst of the present invention includes isoprene, 1,3-butadiene, 2,3-dimethyl-1,
There are 3-butadiene, 1,3-pentadiene, myrcene, etc., which can be used alone or in combination of two or more.
3-Butadiene is preferred.

In the present invention, during the polymerization of the conjugated diene in an inert organic solvent using the lanthanum series rare earth metal catalyst in this way, taking advantage of the high living polymerizability of the catalyst system,
By chain-transferring the polymer growth terminal mainly to the organoaluminum compound (b), the organoaluminum compound is added to the polymer terminal, and subsequently, a specific halogen compound is caused to react with the obtained polymer terminal, and the organoaluminum polymer and A novel polymer obtained by modifying a halide by exchanging it with a halogen to introduce a functional group into the polymer.

This modification has the effect of improving wear resistance, heat generation characteristics, and mechanical characteristics.

In the present invention, the halogen compound to be reacted after the production of the conjugated diene polymer (hereinafter referred to as “component (e)”) is a compound having a structure represented by the above general formula.

Here, the component (e) and the Examples of the compound having the formula: 2-amino-6-chloropyridine, 2,5-dibromopyridine, 4-chloro-2
-Phenylquinazoline, 2,4,5-tribromoimidazole, 3,6-dichloro-4-methylpyridazine, 3,4,5-trichloropyridazine, 4-amino-6-chloro-2-mercaptopyrimidine, 2-amino -4-chloro-6-methylpyrimidine, 2-amino-4,6-dichloropyridine, 6-chloro-2,4-dimethoxypyridine, 2-chloropyrimidine, 2,4-dichloro-6-methylpyrimidine, 4, 6-dichloro-2- (methylthio) pyrimidine,
2,4,5,6-tetrachloropyrimidine, 2,4,6-trichloropyrimidine, 2-amino-6-chloropyrazine, 2,6-
Dichloropyrazine, 2,4-bis (methylthio) -6-chloro-1,3,5-triazine, 2,4,6-trichloro-1,3,5
-Triazine, 2-bromo-5-nitrothiazole, 2
-Chlorobenzothiazole, 2-chlorobenzoxazole and the like.

Further, among the components (e), Examples of the compound having the following include propionyl chloride, octanoic chloride, stearic chloride, benzoic chloride, phthalic chloride, and maleic chloride.

Of these components (e), 2,4,6-trichloro-1,3,5-triazine and benzoic acid chloride are preferred.

The amount of the component (e) used relative to the component (a) is (component (e) / component (a) (molar ratio) = 0.1 to 200, more preferably 0.5 to 100. In addition, the effect of improving abrasion resistance is not exhibited. On the other hand, even when the amount exceeds 200, the effect of improving physical properties is saturated, which is not economically preferable.

This denaturation reaction is performed at 160 ° C. or lower, preferably -30 to +130.
It is desirable to carry out the stirring at a temperature of ° C. for 0.1 to 10 hours, preferably 0.2 to 5 hours.

After completion of the reaction, steam may be blown into the polymer solution to remove the solvent, or a poor solvent such as methanol may be added to solidify the modified polymer, and then dried under a hot roll or under reduced pressure to obtain a polymer. it can. The polymer can also be obtained by directly removing the solvent from the polymer solution under reduced pressure.

The polymer obtained in the present invention is a high cis 1,4-diene polymer, and in the case of polybutadiene, cis 1,4-diene is used.
The 4-bond content is at least 70%, preferably at least 80%.
In the case of polyisoprene, the cis 1,4-bond content is 88% or more.

The high cis 1,4-butadiene-isoprene copolymer has a cis 1,4-bond content of the butadiene unit of 80% or more and a cis 1,4-bond content of the isoprene unit of 88%.
% Or more.

The composition of butadiene and isoprene in the copolymer at this time can be arbitrarily selected.

The molecular weight of the polymer obtained in the present invention can be varied over a wide range, and particularly when used as an industrial rubber product, its Mooney viscosity (ML _{1 + 4} , 100 ° C.)
Is usually in the range of 10 to 120, preferably 15 to 100, but is not particularly limited.

Further, the polymer of the present invention generally has, for example, an infrared absorption spectrum. When modified with a compound having Absorption around 1,500-1650 cm ^-1 based on When modified with a compound having the following formula, the structure having a functional group added thereto can be confirmed by absorption near 1,650 to 1,750 cm ^-1 .

Further, in the gel permeation chromatography (GPC) analysis, when ultraviolet light (UV) of 254 nm is used for a detector, the molecular weight distribution of polybutadiene without using the component (e) cannot be measured.

However, when a compound containing, for example, a phenyl group is used as the component (e), the molecular weight distribution determined by ultraviolet rays and the molecular weight distribution determined by a differential refractometer correspond to each other because the phenyl group absorbs ultraviolet light. It can be confirmed that a functional group has been introduced into the polymer.

Thus, the polymer of the present invention, alone or natural rubber,
Including cis-1,4-polyisoprene, emulsion-polymerized styrene-butadiene copolymer, solution-polymerized styrene-butadiene copolymer, low cis-1,4-polybutadiene, high cis-1,4-polybutadiene, ethylene- Propylene-diene copolymer, chloroprene, halogenated butyl rubber, NB
It is used by blending with R etc., if necessary, aromatic,
Oil-extended with naphthenic or paraffinic oils, then fillers such as carbon black, silica, magnesium carbonate, calcium carbonate, glass fiber, stearic acid,
A common vulcanized rubber compounding agent such as zinc white, an antioxidant, a vulcanization accelerator and a vulcanizing agent can be added to form a composition.

The resulting composition is subjected to vulcanization after molding, tread, undertread, car curse, sidewall,
It can be used not only for tires such as beat parts, but also for hoses, belts, shoe soles, window frames, seal materials, vibration isolating rubber, and other industrial products.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention.

In the examples, parts and% are unless otherwise specified.
It means parts by weight and% by weight.

Various measurements in the examples were based on the following methods.

The reaction between the polymer immediately after being polymerized by the lanthanum series rare earth metal catalyst and the specific halogen compound is confirmed by GPC analysis and infrared analysis by changing the Mooney viscosity before and after the reaction or performing a model reaction with a number average molecular weight of several thousand. Was done.

The Mooney viscosity was measured at a preheating time of 1 minute, a measurement time of 4 minutes, and a temperature of 100 ° C. (according to JIS K6300).

The microstructure of the polymer was determined by an infrared absorption spectrum method (Morello method).

Using the polymer of the present invention, according to the following formulation, kneading and blending with a 230 cc Brabender and a 6-inch roll were performed, and various measurements were performed using a vulcanized product that was vulcanized at 145 ° C. for a predetermined time. . Formulation (parts) Polymer 100 Carbon black (HAF) 50 Zinc white 3 Stearic acid 2 Antioxidant (810NA) ^{* 1} 1 Vulcanization accelerator (TP) ^{* 2} 0.8 Vulcanization accelerator (MSA) ^{* 3} 1 Sulfur 1.5 * 1) N-phenyl-N'-isopropyl-p-phenylenediamine * 2) Sodium dibutyl dithiocarbamate * 3) N-oxydiethylene-2-benzothiazole sulfenamide Tensile properties and hardness are measured according to JIS K6301. did.

As an index of heat build-up, rebound resilience (%) by a Dunlop rebound resilience test was used. This measuring method conformed to BS903. The larger the rebound resilience (%), the better the heat generation and the better.

The abrasion test conformed to ASTM D2228 (pico method). The pico abrasion index was calculated using a butadiene copolymer (Nippon Synthetic Rubber Co., Ltd.)
Of the vulcanized product of Polybutadiene BR-01) manufactured by Pico Method was determined as a reference index of 100. The larger the index, the better the wear resistance.

Example 1 60 g of cyclohexane and 6 g of 1,3-butadiene were charged into a pressure-resistant bottle having an inner volume of 100 ml under a nitrogen atmosphere, and then (a) in the presence of 0.555 mmol of 1,3-butadiene in advance.
Neodymium 2-ethylhexanoate 0.111 mmol, (b)
3.33 mmol of diisobutylaluminum hydride,
(C) 0.222 mmol of diethylaluminum chloride and (d) 0.167 mmol of acetylacetone are mixed, and a catalyst prepared by aging at 40 ° C. for 30 minutes is added.
Polymerization was carried out at 60 ° C. for 1 hour under adiabatic reaction. The polymerization rate of 1,3-butadiene was almost 100%.

Next, (e) 2,4,6-trichloro-1,3,5-
3.3 mmol of triazine (hereinafter referred to as “TCT”) was added.

Thereafter, the mixture was left to stir for 1 hour and solidified with methanol.
The operation of dissolving the obtained polymer in toluene and coagulating with methanol was performed three times to completely remove unreacted TCT. This was dried under reduced pressure at room temperature.

The microstructure of poly-1,3-butadiene obtained by this reaction had a cis-1,4 bond content of 97.4%, a trans-1,4 bond content of 1.2%, and a vinyl bond content of 1.4%.

 The GPC chart of this polymer is shown in FIG.

As apparent from FIG. 2, the molecular weight distribution obtained by the differential refractometer and the molecular weight distribution obtained by the ultraviolet ray (UV, 254 nm) appear in correspondence with the GPC count, and the UV absorption spectrum is lower at the lower molecular weight side. It can be seen that the absorption intensity is large and corresponds to the number of terminals of the polymer.

Next, FIG. 3 shows an infrared absorption spectrum of this polymer. As is evident from FIG. 3, around 1,540 cm ⁻¹ ,
An absorption spectrum based on the 3,5-triazine ring appeared, confirming that TCT had reacted and added to the polymer.

Comparative Example 1 1,3-Butadiene was polymerized in the same manner as in Example 1,
Example 1 except that TCT was not used as the component (e)
A polymer was obtained in exactly the same manner as described above.

The GPC chart of the polymer obtained in Comparative Example 1 is shown in FIG. 4, and the infrared absorption spectrum is shown in FIG.

From Example 1 and Comparative Example 1, it can be seen that the polymer of the present invention has a high cis-1,4 structure and a functional group added thereto, and is a novel polymer which has never existed before.

Example 2 The same operation as in Example 1 was carried out except that the polymer was modified using benzoic acid chloride as the component (e) instead of the TCT of Example 1.

The GPC chart of the obtained polymer is shown in FIG. Sixth
From the figure, it can be seen that a functional group has been added to the polymer.

Example 3 2.5 kg of cyclohexane and 350 g of 1,3-butadiene were charged into a reactor having an internal volume of 5 with a stirrer under a nitrogen atmosphere, and (a) 2-ethyl was added in advance in the presence of 4.6 mmol of 1,3-butadiene. 0.43 mmol of neodymium hexanoate,
(B) 12.1 mmol of triethylaluminum, (b) 9.5 mmol of diisobutylaluminum hydride,
(C) 0.56 mmol of diethylaluminum chloride,
And (d) 0.86 mmol of acetylacetone are mixed,
A catalyst prepared by aging at 40 ° C. for 30 minutes was added, and a reaction was performed at 70 ° C. for 1.5 hours by adiabatic reaction. The polymerization rate of 1,3-butadiene was almost 100%. In order to measure Mooney viscosity, a part of the polymerization solution was withdrawn, coagulated and dried.
The Mooney viscosity was 31.

Next, after the temperature of the polymerization solution was cooled to 60 ° C., 2.88 mmol of TCT was added as the component (e), and the mixture was left to stir for 1 hour.

Then, 2,6-di-t-butyl-p-cresol 2.1 g
Was added, steam coagulated, and dried with a hot roll at 100 ° C. The microstructure of the poly-1,3-butadiene obtained by this reaction had a cis-1,4 bond content of 97.0%, a trans-1,4 bond content of 1.8%, and a vinyl bond content of 1.2%. The Mooney viscosity was 37. Table 1 shows the evaluation results of the physical properties of the vulcanized product.

Comparative Example 2 In the same manner as in Example 3, 1,3-butadiene was polymerized,
Example 1 except that TCT was not used as the component (e)
A polymer was obtained in exactly the same manner as described above.

Table 1 shows the evaluation results of the microstructure and vulcanization properties of the obtained polymer.

Comparative Example 3 Table 1 shows the vulcanization properties of a commercially available polybutadiene (manufactured by Nippon Synthetic Rubber Co., Ltd., polybutadiene BR-01).

It can be seen that the polymer of the present invention obtained by reacting the polymer immediately after polymerization with the lanthanum series rare earth metal catalyst with TCT has greatly improved abrasion resistance, heat generation characteristics and tensile strength.

Example 4 In place of TCT as the component (e) of Example 3, 8.64 mmol of benzoic acid chloride was added, and poly-1,3-butadiene was modified in the same manner as in Example 3. Table 1 shows the evaluation results of the microstructure and vulcanization properties of the obtained polymer.

Comparative Example 4 A polymer was obtained in the same manner as in Example 3 except that 5.1 mmol of carbon tetrachloride was used instead of TCT as the component (e) of Example 3. Table 1 shows the polymerization results and the vulcanization properties of the obtained polymer.

[Effects of the Invention] The present invention provides a novel conjugated diene-based polymer by reacting a polymer obtained by polymerizing a conjugated diene with a lanthanide rare earth metal catalyst in an inert organic solvent, with a specific halogen compound. This is a method for producing a coalesced product. When used as a rubber vulcanizate, the resulting polymer has a specific functional group. When used as an industrial rubber product, it has mechanical properties (especially, modulus and tensile strength) and heat generation. A vulcanizate having good properties and having abrasion resistance greatly improved over known conjugated diene polymers can be obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart for explaining an example of a method for preparing a catalyst used in the present invention, FIG. 2 is a GPC chart of the polymer obtained in Example 1, FIG. FIG. 4 is a GPC chart of the polymer obtained in Comparative Example 1, FIG. 5 is the same infrared absorption spectrum, and FIG. 6 is Example 2.
3 is a GPC chart of the polymer obtained in 1.

Claims (2)

(57) [Claims] (1) (a) (a) a lanthanum series rare earth element compound, and (b) a general formula AlR ¹ R ² R ³ (where R ¹ , R ² and R ³ are the same or different and a hydrogen atom or carbon atom Numbers 1-8
Which is not a hydrogen atom, and is not a hydrogen atom), and if necessary, is not reacted in the presence of a catalyst containing (c) Lewis acid and / or (d) Lewis base. In an active organic solvent, a conjugated diene is polymerized. (X represents a halogen atom) and / or a halogenated isocyano compound having A method for producing a novel conjugated diene-based polymer, comprising reacting an acid halogen compound having (X is the same as described above). 2. The method for producing a novel conjugated diene polymer according to claim 1, wherein the conjugated diene is 1,3-butadiene and / or isoprene.