JPH0155286B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a conjugated diene polymer with controlled molecular weight in the presence of a catalyst containing a lanthanum series rare earth element. Polymerization of butadiene and isoprene using a catalyst containing a rare earth element is described, for example, in Journal of Polymer Science (18 volumes) 3345 (1980), JP-A No. 54-40890, JP-A No. 55-12189, JP-A No. 55-
66903. In addition, polybutadiene obtained using a catalyst containing a rare earth element has a high cis bond content, and is expected to have improved fracture properties due to stretched crystals, etc., making it an industrially interesting material. However, in order to supply various types of polybutadiene depending on the industrial use, it is necessary to find a method to arbitrarily control the molecular weight of the produced polymer. From this perspective, the present inventors conducted intensive studies to obtain industrially useful conjugated diene polymers of arbitrary molecular weights, and found that by using a specific substituted aromatic hydrocarbon as one component of the solvent, the produced polymers could be reduced. We have discovered that the molecular weight of the coalescence can be controlled arbitrarily, and have arrived at the present invention. According to the present invention, (A) the general formula L _o Y ₃ (where L _o is a metal with an atomic number of 57 to 71 in the periodic table and Y is -OR ¹ , -SR ¹ , -NR ¹ , X or
A compound of a lanthanum series rare earth element represented by R ¹ COO−, where R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, and X is a halogen atom excluding fluorine, (B) General formula AlR ² R ³ R ⁴ (wherein R ² , R ³ and R ⁴ are each the same or different and are hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, provided that they are not all hydrogen at the same time) aluminum compound, and (C) general formula AlX _o R ⁵ _3-o (wherein X is a halogen atom excluding fluorine, R ⁵ is a hydrocarbon group having 1 to 8 carbon atoms, n is 1, 1.5,
In polymerizing a conjugated diene in the presence of a catalyst consisting of an aluminum halide compound represented by 2 or 3), in a hydrocarbon polymerization solvent containing 80% by weight or less of a substituted aromatic hydrocarbon having active hydrogen. Provided is a method for producing a conjugated diene polymer, characterized in that the molecular weight of the resulting polymer is controlled by polymerization. Ln used in the present invention is a lanthanum series rare earth element having an atomic number of 57 to 71, and among them, cerium, lanthanum, praseodymium, neodymium, and gadolinium are preferred, and neodymium is particularly preferably used because of its industrial availability. A mixture of two or more rare earth elements may be used. Lanthanum series rare earth element compounds include carboxylates, alkoxides, thioalkoxides,
Halogen and amide forms, particularly carboxylic acid salts, alkoxides, and halogen salts are preferred. Carboxylate salts of rare earth elements are represented by the general formula (R ¹ CO ₂ ) ₃ Ln, where R ¹ has a carbon number of 1 to 20.
hydrocarbon substituents, preferably saturated and unsaturated alkyl, and linear, branched and cyclic, and the carboxyl group is bonded to a primary, secondary or tertiary carbon atom. It is something that exists. Specifically, examples of preferred carboxylic acids include octanoic acid, 2-ethyl-hexanoic acid, oleic acid, stearic acid, benzoic acid, and naphthenic acid. As an alcohol type compound, the general formula Ln
(OR ¹ ) ₃ (in the formula, Ln and R ¹ are as described above), and specifically preferred alcohols include 2
-Ethyl-hexyl alcohol, oleyl alcohol, stearyl alcohol, phenol, benzyl alcohol and the like. As a thioalcohol type compound, the general formula Ln
It is represented by (SR ¹ ) ₃ (in the formula, Ln and R ¹ are as described above), and a specifically preferable thioalcohol is thiophenol. The amide type compound is represented by the general formula Ln(NR ¹ ₂ ) ₃ (wherein Ln and R ¹ are as described above), and specifically, dihexylamine and dioctylamine are preferred. In order to solubilize the above lanthanum series rare earth compound in the polymerization catalyst, a Lewis base and/or
Alternatively, a Lewis acid can be used in combination. The Lewis base or Lewis acid is used in a ratio of 0 to 30 mol, preferably 1 to 10 mol, per 1 mol of the Ln compound (LnY ₃ ), either as a mixture of the two or as a product obtained by reacting the two in advance. Examples of Lewis bases include acetylacetone, tetrahydrofuran, pyridine, N,N'-
Dimethylformamide, thiophene, diphenyl ether, triethylamine, organic phosphorus compounds,
Examples include monohydric or dihydric alcohols. Examples of Lewis acids include hydrogen chloride, hydrogen bromide, hydrogen iodide, carboxylic acids, halogen-substituted carboxylic acids, SnCl ₄ , SiCl ₄ , TiCl ₄ , SnCl ₂
(C ₄ H ₉ ) ₂ , SiCl ₂ (CH ₃ ) ₂ and the like. Specific examples of the organoaluminum compound represented by the general formula AlR ² R ³ R ⁴ of component (B) include triethylaluminum, tributylaluminum, triisobutylaluminum, triisopropylaluminum, diethylaluminium hydride, diisobutylaluminum hydride, trihexyl Aluminum etc. are used. Specific examples of the aluminum halide compound represented by the general formula AlXnR ⁵ _3-o as component (C) include diethylaluminum chloride, ethylaluminum dichloride, ethylaluminum sesquichloride, aluminum trichloride,
Diethylaluminium bromide, ethylaluminum dibromide, dibutylaluminum bromide, diethylaluminium iodide, and the like are used. The composition ratio of the lanthanum series rare earth element compound and the organoaluminum compound (B) is 1:2 to 1:2 in molar ratio.
The ratio is 1:300, preferably 1:10 to 1:150. The composition ratio of the lanthanum series rare earth element compound and the aluminum halide compound (C) is 1:
The ratio is 1 to 1:10, preferably 1:1.5 to 1:5. In addition to the above components (A), (B), and (C) as catalyst components, if necessary, component (D) conjugated diene may be added at a ratio of 0 to 50 moles per mole of component (A) lanthanum series rare earth element compound. May be used in As the conjugated diene used for producing the catalyst, isoprene, butadiene, 1,3-pentadiene, etc. are used like the monomer for polymerization. Although the conjugated diene is not essential as a catalyst component, its combined use has the advantage of further improving the catalyst activity. Catalyst production involves, for example, component (A) dissolved in a solvent,
It consists of reacting (B), (C), and if necessary (D). At this time, the order of addition of each component may be arbitrary.
It is preferable to mix, react, and age each of these components in advance from the viewpoint of improving polymerization activity and shortening the polymerization initiation induction period. It's okay. According to the present invention, when polymerizing a conjugated diene using the catalyst obtained above, the amount of substituted aromatic hydrocarbon having active hydrogen is 80% by weight or less, preferably 0.3 to 80% by weight, more preferably 1% by weight or less. A hydrocarbon polymerization solvent containing ~50% by weight is used. Among the substituted aromatic hydrocarbons having active hydrogen used, those having active hydrogen at the benzyl position are preferred, and specifically, for example, toluene, ethylbenzene, xylene, propylbenzene, isopropylbenzene, mesitylene, 2,4- Examples include dihydronaphthalene. The hydrocarbon polymerization solvent used in the present invention is a hydrocarbon other than a substituted aromatic hydrocarbon having active hydrogen, which is liquid under polymerization conditions, and preferably an aliphatic hydrocarbon having 4 to 8 carbon atoms. saturated hydrocarbons,
Selected from alicyclic saturated hydrocarbons and benzene. Specifically, butane, pentane, hexane, heptane, octane (including isomers), cyclohexane,
benzene and mixtures thereof, especially n-
Hexane and mixed hexane are preferably used. In addition to these, methylene chloride and chlorobenzene can also be used. When the content of the substituted aromatic hydrocarbon having active hydrogen in the hydrocarbon polymerization solvent exceeds 80% by weight, the polymerization activity decreases significantly. Also, considering both molecular weight control effect and polymerization activity, 0.3 to 80% by weight,
Furthermore, 1 to 50% by weight is more preferable. Polymerization temperature is usually -30℃~120℃, preferably 10℃
It ranges from ℃ to 80℃. The polymerization reaction may be carried out either batchwise or continuously. The polymerization reaction is stopped by adding a polymerization terminator to the reaction system after a predetermined polymerization rate is reached, and the conjugated diene polymer is produced by removing the solvent and drying in a conventional manner. Conjugated dienes that can be polymerized with the catalyst of the present invention include isoprene, 1,3-butadiene, 1,3-pentadiene, etc., and they may be used alone or as a mixture of two or more types, and 1,3-butadiene is particularly preferred. The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples unless the gist of the invention is exceeded.
In the examples, Mooney viscosity (measured according to JIS K6383) was used as an index of the molecular weight of the polymer. Example 1 In a 300ml pressure-resistant bottle purged with nitrogen, under nitrogen,
-Mixed solvents of hexane and toluene in various proportions
30g of butadiene (BD) was added to 180g. On the other hand, neodymium octoate (Nd)-acetylacetone-triethylaluminum-diethylaluminum chloride was mixed with BD/Nd=1×10 ⁴ , triethylaluminum/Nd=100, diethylaluminum chloride/Nd=2.5, acetylacetone/Nd=2 (each molar ratio) and polymerized at 60°C for 4 hours. 2 ml of a methanol solution containing 0.2 g of 2,6-ditertiary-butyl-p-cresol was added to stop the reaction. The polymer solution was poured into methanol to precipitate the polymer and dried on a roll at 110°C. Table 1 shows the reaction conditions and the Mooney viscosity of the obtained polymer. For comparison, polymers were obtained by carrying out the polymerization reaction in the same manner as above with lowering the (BD)/Nd ratio in the case of using n-hexane alone and in the case of using toluene alone as the polymerization solvent. The results are shown in Table-1.

[Table] From Table 1, it can be seen that the present invention is excellent in that the molecular weight of polybutadiene can be arbitrarily controlled with a small amount of catalyst. In addition, toluene alone has extremely high polymerization activity.
It's obvious that it's bad. Example 2 A polymer was obtained by polymerizing in the same manner as in Run No. 5 of Example 1, except that 10% by weight each of ethylbenzene, xylene, 2,4-dihydronaphthalene, and mesitylene was used instead of toluene. Also, for comparison, in Run No. 1 of Table 1, n-
Cyclohexane, benzene, and methylene chloride were used instead of hexane, and the polymerization temperature was 30° C. only in the case of methylene chloride, and the other polymers were similarly polymerized to obtain a polymer. The results are shown in Table-2.

[Table] From Table-2, ethylbenzene, xylene, 2,
It is clear that when 4-dihydronaphthalene or mesitylene is used, there is no decrease in polymerization activity and there is a molecular weight regulating effect.

Claims (1)

[Claims] 1 (A) General formula L _o Y ₃ (in the formula, L _o is a metal with an atomic number of 57 to 71 in the periodic table, and Y is -OR ¹ , -SR ¹ , -NR ¹ , X or
A compound of a lanthanum series rare earth element represented by R ¹ COO−, where R ¹ is a hydrocarbon group having 1 to 20 carbon atoms, and X is a halogen atom excluding fluorine, (B) General formula AlR ² R ³ R ⁴ (wherein R ² , R ³ and R ⁴ are each the same or different and are hydrogen or a hydrocarbon group having 1 to 8 carbon atoms, provided that they are not all hydrogen at the same time) aluminum compound, and (C) general formula AlX _o R ⁵ _3-o (wherein X is a halogen atom excluding fluorine, R ⁵ is a hydrocarbon group having 1 to 8 carbon atoms, n is 1, 1.5,
A hydrocarbon polymerization solvent containing 80% by weight or less of a substituted aromatic hydrocarbon (having active hydrogen) in the polymerization of a conjugated diene in the presence of a catalyst consisting of an aluminum halide compound represented by (2 or 3) 1. A method for producing a conjugated diene polymer, which comprises controlling the molecular weight of the resulting polymer by performing polymerization in a medium. 2. The production method according to item 1, wherein the substituted aromatic hydrocarbon having active hydrogen is a substituted aromatic hydrocarbon having active hydrogen at the benzyl position. 3. The manufacturing method according to item 1, wherein the hydrocarbon polymerization solvent is selected from aliphatic saturated hydrocarbons having 4 to 8 carbon atoms, cyclohexane, or benzene.