JPS6320443B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a new method for producing polybutadiene. The method for producing reinforced polybutadiene is to combine a cobalt compound with the general formula AlR _o in an inert organic solvent.
X _3-o (However, R is an alkyl group having 1 to 6 carbon atoms,
phenyl group or cycloalkyl group, X is a halogen atom, n is a number from 1.5 to 2)
In the presence of a cis-polymerization catalyst obtained from a halogen-containing organoaluminum compound represented by
1,3-butadiene is polymerized to produce cis-1,4-polybutadiene, and then this polymerization system is
Further, a cobalt compound, an organoaluminum compound represented by the general formula AlR ₃ (wherein R is the same as above), and a disulfide compound, with or without addition of 1,3-butadiene and/or the above-mentioned solvent, are added. A method of polymerizing 1,3-butadiene in the presence of a 1,2 polymerization catalyst obtained from carbon is known (Japanese Patent Publication No. 17666/1983). However, the above method uses an organoaluminum compound represented by the general formula AlR ₃ as the aluminum component of the 1,2-polymerization catalyst. Therefore, a method was proposed in which a dialkyl aluminum halide was used as the aluminum component of the 1,2-polymerization catalyst (Japanese Patent Application Laid-open No. 88409/1983). _The above publication describes that in a polymerization solvent, a cis- 1,3- in the presence of a 1,4-polymerization catalyst
Butadiene is polymerized to form cis-1,4-polybutadiene, and then a soluble cobalt compound, a dialkyl aluminum halide is added to the polymerization system with or without further addition of 1,3-butadiene and/or said solvent. , 1 consisting of carbon disulfide and an electron-donating organic compound,
A method for producing reinforced polybutadiene is described in which 1,3-butadiene is polymerized in the presence of a 2-polymerization catalyst. However, the reinforced polybutadiene produced by the above method has a melting point of boiling n-hexane insoluble components.
Relatively low at 188-198°C (depending on the example). The inventors used an organoaluminum halide as the organoaluminum compound to
-This invention was completed as a result of research into a method for producing reinforced polybutadiene whose hexane-insoluble content has a melting point of 200°C or higher. That is, the present invention provides cis-1,4 polymerization consisting of a soluble cobalt compound and an organoaluminum halide in a polymerization solvent solution of 1,3-butadiene.
1,3-butadiene is polymerized in the presence of a polymerization catalyst to produce cis-1,4 polybutadiene, and then a soluble cobalt compound, an organoaluminum halide, an organolithium compound, and carbon disulfide or phenyl isothiocyanate are added to the polymerization system. 1,3-butadiene is polymerized in the presence of a 1,2-polymerization catalyst consisting of
30% and a final polybutadiene having a boiling n-hexane soluble content of 95-70%. The manufacturing method of this invention is shown in FIG. In the method of this invention, the soluble cobalt compound which is the cobalt component of the cis-1,4-polymerization catalyst may be any cobalt compound as long as it is soluble in the polymerization solvent used. For example, as such a soluble cobalt compound, a cobalt β-diketone complex or a cobalt β-keto acid ester complex is preferably used. The β-diketone ligand of these cobalt complexes has the general formula (In the formula, each of R ₁ and R ₂ is a hydrogen atom or an aliphatic hydrocarbon group having 1 to 3 carbon atoms,
Each of R ₃ and R ₄ is an aliphatic hydrocarbon group having 1 to 3 carbon atoms. ) β-diketones, and as β-keto acid esters of the ligand, the general formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same as above.) β-keto acid esters are mentioned. Particularly preferred complexes are cobalt () acetylacetonate, cobalt () acetylacetonate, and cobalt acetoacetic acid ethyl ester complex. Also, as a soluble cobalt compound, carbon number 6
Cobalt salts of the above organic carboxylic acids, such as cobalt octoate, cobalt naphthenate, cobalt benzoate, etc., can be used. Furthermore, as a soluble cobalt compound, for example, a halogenated cobalt complex, that is, a general formula CoXn.Ym (3) (wherein, X is a halogen atom, particularly preferably a chlorine atom, and n is an integer of 2 or 3, A complex represented by Y is a ligand and m is an integer of 1 to 4 can also be suitably used. In the above formula (3), the ligand is any ligand known to form a complex with cobalt halide, such as amines such as pyridine, triethylamine, tributylamine, and dimethylaniline;
Alcohols such as methyl alcohol and ethyl alcohol and N,N-dimethylformamide,
Examples include N,N-dialkylamides such as N,N-dimethylacetamide and N,N-diethylformamide. Particularly preferred cobalt halide complexes include cobalt chloride pyridine complexes and cobalt chloride ethyl alcohol complexes. In the method of this invention, the organoaluminum halide that is the aluminum component of the cis-1,4-polymerization catalyst has the general formula AlR _o X _3-o (where R is an alkyl group having 1 to 6 carbon atoms, a phenyl group, or is an alkyl group, X is a halogen atom, n
is a number from 1.5 to 2). As the organoaluminum halide, dialkylaluminum halides such as diethylaluminum monochloride, diethylaluminum monobroride, diisobutylaluminum monochloride, and alkylaluminum sesquihalides such as ethylaluminum sesquichloride can be suitably used. The amount of the cis-1,4 polymerization catalyst used is such that the soluble cobalt compound is 0.005 mmol or more, especially 0.01 mmol or more, and the organoaluminum halide is 0.5 mmol or more, especially 1 mmol or more, per 1 mole of 1,3-butadiene. It is preferable that Further, the molar ratio (Al/Co) of the organoaluminium halide to the soluble cobalt compound is preferably 5 or more, particularly 15 or more. The polymerization solvent for the polymerization solvent solution of 1,3-butadiene is not particularly limited as long as it is an organic solvent that can dissolve the formed cis-1,4-polybutadiene, but aromatic solvents such as benzene, toluene, and xylene can be used. Hydrocarbons, aliphatic hydrocarbons such as n-heptane and n-hexane, alicyclic hydrocarbons such as cyclohexane, and their halides, such as chlorobenzene, O-dichlorobenzene, methylene chloride, 1,2-dichloroethane, Examples include 1,1,2-trichloroethane. 1,
The amount of water in the polymerization solvent solution of 3-butadiene is 50
mg/(ppm) or less, particularly preferably 10 to 50 mg/. The polymerization temperature for cis-1,4-polymerization in the method of this invention is preferably -20 to 80°C, particularly 20 to 70°C, the polymerization pressure may be normal pressure or higher, and the polymerization time is 10 minutes to 5 hours. A range is preferred. In addition, cis-1,4 of 1,3-butadiene in the reaction system
-The concentration during polymerization may be in the range of 5 to 40% by weight based on the total polymerization solution. The cis-1,4-polymerization described above is cis-1,4-
The structural content is 90% or more, especially 95% or more, and the intrinsic viscosity [η] (measured in toluene at 30°C) is 1 to 4, especially
It is preferable to carry out the reaction so that cis-1,4-polybutadiene having a molecular weight of 1.3 to 3 is produced. In order to adjust the intrinsic viscosity to a suitable value, known molecular weight regulators, for example, non-conjugated dienes such as cyclooctadiene (hereinafter abbreviated as COD) and allene, or α-olefins can be used. In the method of this invention, the above-mentioned cis-1,
A 1,2-polymerization catalyst is present in a polymerization solution containing cis-1,4-polybutadiene obtained in the 4-polymerization step and a cis-1,4-polymerization catalyst to convert 1,3-butadiene into 1,2-polybutadiene. -It polymerizes. The soluble cobalt compound which is the cobalt component of the 1,2-polymerization catalyst can be exactly the same as the cobalt component of the cis-1,4-polymerization catalyst described above. The organoaluminum halide which is the aluminum component of the 1,2-polymerization catalyst is the above-mentioned cis-1,4
The same aluminum component as the polymerization catalyst can be used. The organolithium compound as a 1,2-polymerization catalyst component used in the method of the present invention is an alkyllithium compound, an aryllithium compound, an alkylene dilithium compound or an allyl dilithium compound. As the organolithium compound, alkyllithium compounds such as ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, and amyllithium can be suitably used. In the method of this invention, carbon disulfide or phenyl isothiocyanate, preferably carbon disulfide, is used as the 1,2-polymerization catalyst component. In the method of this invention, 1,
It is necessary to polymerize 3-butadiene. Even if 1,3-butadiene is polymerized in the presence of a catalyst consisting of other three components without using an organolithium compound, it is not possible to obtain reinforced polybutadiene with a high melting point, high molecular weight, and a content insoluble in boiling n-hexane. (Comparative Example 1). The amount of each component of the 1,2-polymerization catalyst used in the method of this invention is such that the cobalt compound soluble in the polymerization solvent is
0.0005 to 0.1 mol%, organoaluminum halide 0.01 to 1 mol%, organolithium compound 0.01 to 1 mol%
Preferably, the amount of carbon disulfide or phenyl isothiocyanate is 0.001 to 1 mol%. In addition, the amount of organoaluminum halide is 10 to 500 mol per 1 mol of soluble cobalt compound,
In particular, 20 to 200 mol is preferable, and the amount of the organolithium compound is 5 to 5 mol per mol of the soluble cobalt compound.
The amount of carbon disulfide or phenyl isothiocyanate is preferably 0.1 to 500 mol, particularly 1 to 500 mol, per mol of the soluble cobalt compound. Further, the amount of the organolithium compound is preferably 1 mol or more per 1 mol of water present in the polymerization system (the amount of water present in the polymerization solvent solution of 1,3-butadiene); The amount is preferably 1.5 times the mole or less of the total amount of the organic aluminum halide and the organic aluminum halide. Also, as an organoaluminum halide, the general formula
When using a compound represented by AlR _1.5 X _1.5 (R,
It is preferably 0.5 mol or more. There are no particular restrictions on the order and method of addition of each component of the 1,2 polymerization catalyst, but the order of addition of carbon disulfide and phenyl phenyl isothiocyanate is preferably at the end of each component. However, as shown in Example 2, it can also be added in advance before cis-1,4 polymerization. Alternatively, the organolithium compound can be added directly to the cis-1,4 polymerization solution as a solution in a hydrocarbon solvent such as hexane or benzene.
Before adding the organolithium compound to the cis-1,4 polymerization solution, 1,3-butadiene, carbon disulfide,
Care must be taken because the 1,2-polymerization activity may be significantly reduced when brought into contact with phenyl phenylisothiothianate. The polymerization temperature for 1,2-polymerization in the method of this invention is preferably -20 to 80°C, particularly 20 to 60°C, the polymerization pressure may be normal pressure or higher, and the polymerization time is 10 to 10°C.
A range of minutes to 5 hours is preferred. The solvent for 1,2-polymerization is the same as the cis-1,4-polymerization solvent. When carrying out this invention, the total amount of 1,3-butadiene and solvent used for polymerization must be reduced to cis-
It may be added in the 1,4-polymerization step, or in the cis-1,4-polymerization step of 1,3-butadiene, part of the 1,3-butadiene and/or solvent may be added, and then the 1,2 - In the polymerization step, the remaining amount of 1,3-butadiene and/or solvent may be added. At this time, the concentration of 1,3-butadiene in the reaction system is preferably in the range of 3 to 40% by weight based on the total polymerization solution. The method of the present invention can also be carried out by carrying out cis-1,4-polymerization and subsequent 1,2-polymerization in the same reaction vessel as a batch method, or by carrying out cis-1,4-polymerization followed by 1,2-polymerization in the same reaction vessel as a batch method, or by carrying out cis-1,4-polymerization followed by 1,2-polymerization as a continuous method. It can also be carried out industrially by continuously polymerizing 1,3-butadiene in a 1,4-polymerization zone and a 1,2-polymerization zone connected thereto. In the process of this invention, the polymerization is carried out until a final polybutadiene is produced having a boiling n-hexane insoluble content of 5 to 30% and a boiling n-hexane soluble content of 95 to 70%. A known method can be applied to obtain polybutadiene after the completion of the polymerization reaction. For example, after the polymerization reaction is complete, a large amount of a polar solvent such as alcohol or water that reacts with organoaluminum halide is added to the polymerization solution, or a large amount of polar solvent is added to the polymerization solution, or an inorganic solvent such as hydrochloric acid or sulfuric acid is added to the polymerization solution. Polymerization of 1,3-butadiene can be carried out by adding a small amount of polar solvent containing acid, organic acids such as acetic acid and benzoic acid, monoethanolamine and ammonia into the polymerization solution, or introducing hydrogen chloride gas into the polymerization solution. After stopping, the polymer is precipitated by adding a precipitating agent such as methanol or by flashing (by blowing in water vapor or not blowing in water to remove the solvent by evaporation), and after separation, it is dried to obtain polybutadiene rubber. be able to. The polybutadiene obtained by the method of this invention consists of a boiling n-hexane soluble fraction and a boiling n-hexane insoluble fraction (HI), with the boiling n-hexane insoluble fraction being 5 to 30%, and the boiling n-hexane insoluble fraction (HI). Hexane soluble content is 95-70%. Preferably, the boiling n-hexane soluble fraction has an intrinsic viscosity ([η]) (measured at 30°C in toluene) of 1 to 5 and a cis-1,4 structure content.
92% or more, and the intrinsic viscosity ([η]) of the boiling n-hexane insoluble matter (measured at 135°C in tetralin) is 0.5 to
5, the 1,2-structure content is 85% or more, and the melting point is 200 to 220°C. The 1,2-structure portion of the boiling n-hexane insoluble portion mainly has a syndiotactic 1,2-structure. The polybutadiene obtained by the method of the present invention can be blended with known compounding agents conventionally used for natural rubber and high cis-1,4-polybutadiene. Furthermore, the polybutadiene obtained by the method of the present invention can also be used by blending it with natural rubber or other synthetic rubber. Next, examples and comparative examples will be shown. In the description of Examples and Comparative Examples, the boiling n of polybutadiene
-For hexane-insoluble matter, dissolve 2g of reinforced polybutadiene in 200ml of n-hexane at room temperature, then
The insoluble matter was extracted using a Soxhlet extractor for 4 hours, the extracted residue was vacuum-dried, and its weight was precisely weighed. In addition, the boiling n-hexane soluble fraction is the n-hexane soluble fraction obtained as above and the n-hexane soluble fraction extracted by the Soxhlet extractor.
- Determined by removing hexane by evaporation, vacuum drying, and accurately weighing. In addition, the boiling n-hexane soluble content of the reinforced polybutadiene and the cis-1,
The 4-structure content was measured by infrared absorption spectroscopy (IR), the 1,2-structure content of boiling n-hexane-insoluble components was measured by nuclear magnetic resonance spectroscopy (NMR), and the melting point of boiling n-hexane-insoluble components was measured by nuclear magnetic resonance spectroscopy (NMR). (MP) was determined by the peak temperature of the endothermic curve measured by a self-recording differential calorimeter (DSC). In addition, the boiling n-hexane soluble content of the reinforced polybutadiene and the intrinsic viscosity ([η]) of the polybutadiene after cis-1,4 polymerization are the values measured in toluene at 30°C. The intrinsic viscosity ([η]) of the hexane-insoluble portion is the value measured in tetralin at 135°C. Example 1 85 g of dried 1,3-butadiene was dissolved in 860 ml of dehydrated benzene in a separable flask with an inner volume of 2 and equipped with a thermometer, a stirring rod, and a nitrogen gas inlet tube, with the air replaced with nitrogen. Add a benzene solution of 3-butadiene (containing 1.0 mmol of water),
While keeping the liquid temperature at 70℃, add 4.6 mmol of cyclooctadiene and 4.0 mmol of diethylaluminum monochloride to this benzene solution of 1,3-butadiene.
After sequentially adding mmol of cobalt octoate and 0.043 mmol of cobalt octoate with stirring, cis-1,4 polymerization of 1,3-butadiene was carried out at 40° C. for 10 minutes while continuing to stir. The polymer had a cis-1,4 structure content of 96% or more and [η] of 2.4.
Immediately after cis-1,4 polymerization, n-butyllithium
After adding 2.0 mmol and 0.13 mmol of carbon disulfide, 1,3-butadiene was 1,2-polymerized at 40° C. for 8 minutes with stirring. A small amount of 2,6-di-tert-butyl-4-methylphenol and 1 methanol containing hydrochloric acid were added to the resulting polymer product mixture to terminate the polymerization reaction. The precipitated polymer was collected and dried under reduced pressure at about 20°C to obtain 50.8 g of polybutadiene. This polybutadiene contains 15.7% boiling n-hexane insoluble matter, 15.7% boiling n-hexane insoluble matter,
2-The structural content is 92.0%, the melting point is 204℃, the intrinsic viscosity ([η]) is 4.0, and the cis-1,4-structural content of the boiling n-hexane soluble fraction is 96.2.
%, and the intrinsic viscosity ([η]) (toluene, 30℃) is
It was 2.3. Examples 2 to 6 Example 1 except that the polymerization conditions were changed as shown in Table 1.
I did the same thing. The results are shown in Table 2.

【table】

【table】

[Table] Comparative Example 1 The cis-1,4 structure content was 97% in the same manner as in Example 1 except that n-butyllithium was not added.
65 g of cis-1,4 polybutadiene was obtained. Example 7 A benzene solution containing 24% by weight of 1,3-butadiene was put into an autoclave with an internal volume of 20 and equipped with a stirring device, and the water concentration was adjusted to 1.4 mmol/1.
It was adjusted to At 22°C, 49.5 mmol of diethylaluminium monochloride and 13 g of 1,5-cyclooctadiene were added, and the temperature was raised to 40°C. 0.17 mmol of cobalt octoate was added, and the temperature was raised to 40°C while cooling.
Polymerization was carried out for 30 minutes. Thereafter, 25 mmol of n-butyllithium, 0.15 mmol of cobalt octoate, and 1.95 mmol of carbon disulfide were successively added to this solution, and the mixture was reacted at 40° C. for 30 minutes. Polymerization was terminated by adding 30 ml of concentrated hydrochloric acid and 3 methanol containing 60 g of 2,6-di-tert-butyl-4-methylphenol to the polymer production mixture. Thereafter, the polymer solution was added to a storage tank containing 15 methanol with stirring to precipitate the polymer. The polymer was dried under vacuum overnight below 45°C. Polymer yield was 1.25Kg. This polymer has a boiling n-hexane insoluble content of 12.7
%, the 1,2-structure content of the boiling n-hexane insoluble fraction is 93.2%, the melting point is 205°C, the intrinsic viscosity is 4.2, and the boiling n-hexane soluble fraction has a cis-1,4- structure content of 93.2%. The structural content was 98.3% and the intrinsic viscosity was 2.1.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the flow of the polybutadiene production method of the present invention.

Claims (1)

[Scope of Claims] 1. 1,3-Butadiene is polymerized in a polymerization solvent solution of 1,3-butadiene in the presence of a cis-1,4 polymerization catalyst consisting of a soluble cobalt compound and an organoaluminium halide to produce cis-1,3-butadiene. A cis-1,4 polybutadiene with a -1,4 structure content of 90% or more and an intrinsic viscosity [η] of 1 to 4 (measured at 30°C in toluene) is produced, and then a soluble cobalt compound is added to this polymerization system. , 1,3-butadiene is polymerized in the presence of a 1,2-polymerization catalyst consisting of an organoaluminum halide, an organolithium compound, and carbon disulfide or phenyl isothiocyanate, so that the content insoluble in boiling n-hexane is 5 to 30%, A method for producing reinforced polybutadiene, characterized in that a final polybutadiene is produced with a boiling n-hexane soluble content of 95 to 70%. 2 In a polymerization solvent solution of 1,3-butadiene
2. The production method according to claim 1, wherein water is present at a concentration of 50 ppm or less, and the organolithium compound, which is a component of the 1,2-polymerization catalyst, is present in an equimolar amount or more relative to the water.