JPH0238081B2 - HOKYOHORIBUTA JENGOMUNOSEIZOHO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to converting 1,3-butadiene into cis-1,
The present invention relates to an improvement in a method for producing reinforced polybutadiene rubber by performing tetrapolymerization and then 1,2 polymerization. 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 this polymerization system is subsequently
Furthermore, a cobalt compound, an organoaluminum compound represented by the general formula AlR ₃ (where R is the same as above), and a disulfide compound, with or without addition of 1,3-butadiene and/or the above-mentioned solvent. 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 method for producing polybutadiene rubber described in the above publication uses a 1,2 polymerization catalyst obtained from a cobalt compound, an organoaluminum compound represented by the general formula _AlR3 , and carbon disulfide in the second step. , 3-butadiene, and the polymerization activity (yield of 1,2-polybutadiene per unit time and unit amount of catalyst) of this 1,2 polymerization catalyst is higher than that of a cis-1,4 polymerization catalyst. This has the disadvantage that the yield of polymer per unit time is extremely low. moreover,
In the method for producing polybutadiene rubber described in the above publication, carbon disulfide, which is a component of the 1,2 polymerization catalyst, is added during the 1,2 polymerization. After the completion of the polymerization reaction, it is necessary to separate carbon disulfide from 1,3-butadiene and an inert organic solvent, but carbon disulfide cannot be completely separated from these two components, especially 1,3-butadiene, by distillation. On the other hand, when carbon disulfide comes into contact with a halogen-containing organoaluminum compound in the absence of moisture, it is easy to cause side reactions, and the side reaction products produced in this side reaction are - It is difficult to handle carbon disulfide because it significantly inhibits the cis polymerization of butadiene, and therefore it has been difficult to commercialize the production of the above-mentioned reinforced polybutadiene rubber. Therefore, the inventors completed this invention as a result of intensive research aimed at improving the drawbacks of conventionally known methods for producing reinforced polybutadiene rubber. That is, the present invention provides a method in which 1,3-butadiene is cis-1,4-polymerized and then 1,2-polymerized, in which the total amount of 1,3-butadiene and an inert organic solvent is 20 mmol or less per 1. 1,3-butadiene is polymerized in an inert organic solvent solution containing an amount of carbon disulfide and 0.2 mmol of water in the presence of a cis-1,4 polymerization catalyst containing a cobalt compound as a component. Cis-1,4 polybutadiene is produced, and the polymerization reaction mixture is added to the obtained polymerization reaction mixture.
In addition to adding 1 to 50 parts by weight of 1,3-butadiene per 100 parts by weight, the general formula AlR ₃ which is a component of the 1,2 polymerization catalyst other than the carbon disulfide (wherein R is a carbon number of 1 to 6 An organoaluminum compound represented by an alkyl group, phenyl group or cycloalkyl group) and optionally a cobalt compound which is another component of the 1,2 polymerization catalyst are added to convert 1,3-butadiene into 1,3-butadiene. Double polymerization, boiling n
- A process for producing reinforced polybutadiene, characterized in that it produces a final polybutadiene rubber consisting of 5 to 30% by weight of hexane insolubles and 95 to 70% of boiling n-hexane solubles. According to the method of this invention, 1, 2 polymerization,
Since the yield of 2-volibutadiene can be increased, the yield of polymer (reinforced polybutadiene rubber) per unit time can be increased. Furthermore, according to the method of the present invention, despite the presence of carbon disulfide in the polymerization system during cis-1,4 polymerization, cis-1,4 polymerization is not adversely affected, and after the completion of the polymerization reaction, carbon disulfide is present in the polymerization system. There is no need to separate carbon sulfide from 1,3-butadiene or an inert organic solvent;
These mixtures can be recycled and used. In addition, since the concentration of carbon disulfide is already uniform at the inlet of the 1,2 polymerization tank, the polymerization reaction of 1,3-butadiene by the 1,2 polymerization catalyst becomes uniform, and the polymerization in the 1,2 polymerization tank becomes uniform. The amount of adhesion is reduced, and continuous operation time can be extended. In the method of this invention, 1,3-butadiene and an inert organic solvent, and the total amount thereof per 1
20 mmol or less, preferably 0.01 to 20 mmol,
Particularly preferably, carbon disulfide and water are present in the above amounts in the solution, such as by mixing 0.01 to 10 mmol of carbon disulfide and 0.2 to 5 mmol, preferably 0.5 to 5 mmol of water. It is necessary to let it happen. Even if the amount of carbon disulfide, which is a component of the 1,2 polymerization catalyst, present in the solution is greater than the above amount, the 1,2
This is not preferable because the polymerization activity of the double polymerization catalyst does not improve, but rather the amount of unrecovered carbon disulfide increases. Further, if the amount of water present in the solution is outside the above range, the polymerization activity of the cis-1,4 polymerization catalyst and the 1,2 polymerization catalyst will decrease, which is not preferable. As a method for making each of these components exist in a solution, for example, a method for mixing each component, a method known per se can be employed. If the 1,3-butadiene and inert organic solvent already contain a certain amount of carbon disulfide or water, such as when reusing purified recovered solvent, only the missing components should be added. Just that is enough. Alternatively, a compound that decomposes in the polymerization system to generate carbon disulfide may be used. As the inert organic solvent, cis-1,4
Can dissolve polybutadiene
There is no particular restriction as long as the organic solvent does not adversely affect the 1,4 polymerization catalyst and the 1,2 polymerization catalyst, but aromatic hydrocarbons such as benzene, toluene, xylene, n-heptane, n-hexane, etc. Examples include aliphatic hydrocarbons, alicyclic hydrocarbons such as cyclohexane and cyclopentane, and halogen compounds thereof, such as chlorobenzene and methylene chloride. The ratio of the inert organic solvent and 1,3-butadiene is such that the ratio of 1,3-butadiene to the total amount of the inert organic solvent and 1,3-butadiene is 5 to 40.
Preferably it is 10 to 35% by weight, especially 10 to 35% by weight. In the method of this invention, the concentration of each component in the solution is adjusted by, for example, mixing 1,3-butadiene, an inert organic solvent, carbon disulfide, and water, and the mixture is preferably kept at a temperature below 10°C. In this inert organic solvent, the cis-
In the presence of a cis-1,4 polymerization catalyst containing a cobalt compound as one component, such as a 1,4 polymerization catalyst, 1,3-
Butadiene is polymerized to produce cis-1,4 polybutadiene. In the method of the present invention, before adding cis polymerization catalyst components such as a halogen-containing organoaluminum compound and a cobalt compound to the polymerization system, a predetermined amount of water is allowed to be present to remove the carbon disulfide. Side reactions can be suppressed, and cis-1,4 polybutadiene can be obtained in high yield despite the presence of carbon disulfide in the polymerization system. The cobalt compound which is one component of the cis-1,4 polymerization catalyst is not particularly limited as long as it is soluble in the inert organic solvent used. For example, as such a cobalt compound, a cobalt β-diketone complex or a cobalt β-keto acid ester complex is preferably used. The β-diketone which is the 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 β-keto acid esters of the ligand include 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 include cobalt () acetylacetonate, cobalt () acetylacetonate,
It is a cobalt acetoacetate ethyl ester complex. Further, as the cobalt compound, a cobalt salt of an organic carboxylic acid having 6 or more carbon atoms, such as cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. can be used. Furthermore, as a cobalt compound, for example, a halogenated cobalt complex, that is, a general formula CoX _o Y _n (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-dialkylamide such as N,N-dimethylacetamide and N,N-dimethylformamide. Particularly preferred cobalt halide complexes include cobalt chloride pyridine complexes and cobalt chloride ethyl alcohol complexes. As the aluminum component of the cis-1,4 polymerization catalyst, halogen-containing organoaluminum compounds are preferably used, such as diethylaluminum monochloride, diethylaluminum monobromide, diisobutylaluminum monochloride, ethylaluminum sesquichloride, etc. can. In the method of this invention, the cis-1,4
The amount of the polymerization catalyst used is such that the halogen-containing organoaluminum compound is 0.1 mmol or more, especially 0.5 to 50 mmol, and the cobalt compound is 0.001 mmol or more, especially 0.005 mmol or more, per 1 mole of 1,3-butadiene. preferable. In addition, the molar ratio (Al/Co) of the halogen-containing organoaluminum compound to the cobalt compound is 5 or more, especially 15
It is preferable that it is above. In the method of this invention, the polymerization temperature for cis polymerization is preferably -20 to 80°C, particularly 5 to 50°C, the polymerization pressure may be normal pressure or increased pressure, and the polymerization time (average zone retention in the cis polymerization tank) is Although the time varies depending on the catalyst concentration, monomer concentration, polymerization temperature, etc., it is usually preferably in the range of 10 minutes to 2 hours. In particular, it is preferable to carry out cis polymerization so that the polymer concentration after cis polymerization is 80 to 160 g/g/. Further, cis polymerization is carried out by stirring and mixing the solution in a cis polymerization tank. The polymerization tank used for cis polymerization is a polymerization tank equipped with a high viscosity liquid stirring device, for example,
The device described in Japanese Patent No. 2645 can be used. The above cis polymerization has a cis-1,4 structure content of 90
% or more, especially 95% or more, and cis-1,4 polybutadiene having an intrinsic viscosity [η] of toluene at 30°C of 1.5 to 8, particularly 1.5 to 5 is preferably produced. [η] 30°C In order to adjust the toluene to an appropriate value, known molecular weight regulators such as non-conjugated dienes such as cyclooctadiene and allene,
Alternatively, alpha-olefins such as butene-1 can be used. Additionally, known gel inhibitors can be used to suppress the formation of gel during cis polymerization. In the method of this invention, cis-1,4 polybutadiene obtained as described above, cis-
1 to 50 parts by weight, preferably 1 to 20 parts by weight of 1,3 per 100 parts by weight of the polymerization reaction mixture containing the 1,4 polymerization catalyst and carbon disulfide.
- It is necessary to add butadiene. The temperature of 1,3-butadiene to be added is 20℃ or less, especially 0℃
The following are preferred. If the amount of 1,3-butadiene added is less than the lower limit, 1,2-butadiene during 1,2 polymerization
This is not preferable because the yield of polybutadiene does not increase, and even if the amount of 1,3-butadiene added is greater than the above upper limit, the yield of 1,2-polybutadiene during 1,2 polymerization does not increase, but rather increases the amount of unreacted 1,2-polybutadiene. ,3-
This is not preferred because the energy required to recover butadiene increases. 1,3-butadiene may be added as it is, or may be added as a mixture with an inert organic solvent containing a high concentration of 1,3-butadiene. The cis polymerization according to the present invention is highly active even at high temperatures of 40°C or higher;
A polymerization temperature of is used. However, since the activity of 1,2 polymerization decreases considerably at temperatures above 50°C, it is necessary to cool the cis polymerization reaction mixture. The method of adding cold monomer to the 1,2 polymerization tank for cooling is an excellent method, as will be described later. In the method of this invention, a predetermined amount of 1,3-butadiene is added to the polymerization reaction mixture, and organic aluminum represented by the general formula AlR ₃ , which is a component of the 1,2 polymerization catalyst other than the carbon disulfide, is added to the polymerization reaction mixture. compound and optionally a cobalt compound which is another component of the 1,2 polymerization catalyst.
- Polymerizing butadiene to produce a final polybutadiene rubber consisting of 5-30% by weight of boiling n-hexane insolubles and 95-70% of boiling n-hexane solubles. Examples of the organoaluminum compound represented by the general formula AlR ₃ which is the aluminum component of the 1,2 polymerization catalyst include trietheraluminum, trimethylaluminum, triisobutylaluminum, triphenylaluminum, and the like. Examples of the cobalt component of the 1,2 polymerization catalyst include the same cobalt compounds as mentioned above as one of the components of the cis-1,4 polymerization catalyst. Furthermore, as a soluble cobalt compound (1,
3-butadiene) [1-(2-methyl-3-butenyl)-π-allyl]cobalt,
Cobalt complexes of diolefins can be preferably used. It can also be obtained by mixing a cobalt compound and trialkylaluminum in the presence of 1,3-butadiene in an inert organic solvent (polymerization solvent) by the method described in JP-A-57-125206. The mixture containing the 1,3-butadiene complex of cobalt can be used as is by the in situ method. In the method of this invention, if the cobalt compound in the cis polymerization catalyst and the cobalt compound in the 1,2 polymerization catalyst are the same, the amount of cobalt compound required for the 1,2 polymerization is also added during the cis polymerization. However, it is also possible to select conditions in which only the organoaluminum compound is added during the 1,2 polymerization. The organoaluminum compound and cobalt compound (in the case of adding a cobalt compound during mono- and bipolymerization) represented by the above general formula AlR ₃ are mixed with an inert organic solvent and added to the polymerization reaction mixture after cis-polymerization. However, it is preferable to add the above-mentioned 1,3-butadiene or a mixture with an inert organic solvent containing a high concentration of 1,3-butadiene to be added to the polymerization reaction mixture. 1 above,
1,3-butadiene, a cobalt compound, and a part of the organoaluminum compound were mixed by further adding a part of the organoaluminum compound represented by the general formula AlR ₃ to the solution in which the cobalt compound was added to 3-butadiene. After that, by adding it to the cis polymerization reaction mixture, the activity of 1 and 2 polymerization can be increased. In this case, the amount of organoaluminium mixed with 1,3-butadiene is preferably at least the same mole as the cobalt compound and at most 10 times the mole, particularly preferably at most 3 times the mole. By reacting a cobalt compound and an organoaluminum compound in 1,3-butadiene, the cobalt compound can be converted into the aforementioned (1,3-butadiene) [1-(2-methyl-3) suitable for 1,2 polymerization. −
butenyl)-π-allyl]cobalt in high yield. The amount of the 1,2 polymerization catalyst used varies depending on the type and combination of each catalyst component and the polymerization conditions, but the cobalt compound should be 0.005 mmol or more per mole of 1,3-butadiene in the polymerization system, especially
0.01-5 mmol, organoaluminum compound
It is preferred that the amount of carbon disulfide is at least 0.1 mmol, especially from 0.5 to 50 mmol, and at least 0.001 mmol, especially from 0.01 to 10 mmol. In the method of this invention, the polymerization temperature for 1,2 polymerization is preferably -20 to 80°C, particularly 5 to 50°C, the polymerization pressure may be normal pressure or increased pressure, and the polymerization time is 10 minutes to 2 hours. A range of is preferred. In particular, 1,
It is preferable to perform the 1- and 2-polymerization so that the polymer concentration after the 2-polymerization is 80 to 160 g/2. Also,
The 1,2 polymerization is carried out by stirring and mixing the solution in a 1,2 polymerization tank. As the polymerization tank used for 1,2 polymerization, the viscosity of the polymerization reaction mixture becomes higher during the 1,2 polymerization, and the polymer tends to adhere to the inside of the polymerization tank, so the polymerization tank used is as described in Japanese Patent Publication No. 1982-2645. It is preferable to use a polymerization tank equipped with a scraping member for scraping off polymer adhering to the inner wall of the polymerization tank and a material propelling device (for example, a screw shaft stirrer or a threaded ribbon stirrer). The temperature for 1,2 polymerization is often lower than that for cis polymerization, and therefore it is preferable to cool the 1,2 polymerization tank further than the cis polymerization tank. However, it was observed that the amount of polymer adhering to the walls of the polymerization tank tended to increase when the temperature of the cooling brine was low. In the method of the invention,
Add cold monomer from inside, raise the temperature of the cooling water, reduce the amount of cooling water, etc. to increase the cooling temperature as much as possible, or in some cases, heat it from the outside. It also becomes possible to control the polymerization temperature. In particular, by dividing the 1,2 polymerization into two stages, prepolymerization and main polymerization, and adding the 1,2 polymerization catalyst only in the prepolymerization, the inert organic solvent generated during the 1,2 polymerization can be Problems caused by 1,2-polybutadiene insoluble in 1,2-polybutadiene adhering to the 1,2-polymerization tank, such as the fact that the time during which 1,2-polymerization can be continuously operated is significantly shorter than that for cis-polymerization. Effective for improvement. in this case,
A polymerization tank equipped with the above-mentioned scraping member and material propulsion device is used as a polymerization tank for prepolymerization, and the polymerization time (residence time) in prepolymerization is 5 to 60% of the total polymerization time for 1 and 2 polymerizations. is preferable. During 1,2 polymerization, the concentration of 1,3-butadiene in the polymerization system is preferably 7 to 35% by weight. A method known per se can be applied to obtain polybutadiene rubber after the completion of the polymerization reaction. For example, a polymerization reaction mixture obtained by 1,2 polymerization is preferably supplied to a polymerization termination tank, and a polymerization termination agent is added to this polymerization reaction mixture to terminate the polymerization, and then the solid content is reinforced. Separate and obtain polybutadiene rubber. The polymerization terminator may be any compound that reacts with a halogen-containing organoaluminum compound and an organoaluminum compound represented by the general formula _AlR3 , such as alcohols such as methanol and ethanol, water, hydrochloric acid, sulfuric acid, etc. Examples include inorganic acids, organic acids such as benzoic acid, monoethanolamine, ammonia, phosphite esters such as tris(nonylphenyl)phosphite, and hydrogen chloride gas. Particularly preferred polymerization terminators include phosphorous esters.
These may be added alone to the polymerization reaction mixture, or may be added as a mixture with water, alcohol, or an inert organic solvent. After stopping the polymerization of 1,3-butadiene, a precipitant such as methanol is added to the polymerization reaction mixture, or the solid content is removed by flashing (by blowing or not blowing water vapor to remove the solvent by evaporation). Polybutadiene rubber can be obtained by precipitating the polymer and separating and drying it. It is preferable to blend an anti-aging agent into the polybutadiene by adding the anti-aging agent to a polymerization reaction mixture after stopping the polymerization of 1,3-butadiene or to a slurry of polybutadiene rubber. In addition, from the mixture containing unreacted 1,3-butadiene, an inert organic solvent, and carbon disulfide (referred to as a recovery solvent), which is the remainder obtained by separating the solid content of reinforced polybutadiene rubber from the polymerization reaction mixture, The 1,3-butadiene, inert organic solvent, and carbon disulfide purified by the purification process including distillation can be recycled and reused. The polybutadiene rubber obtained by the method of this invention has a boiling n-hexane insoluble content of 5 to 30% by weight, a boiling n-hexane soluble content of 95 to 70% by weight, and a boiling n-hexane insoluble content of 5 to 30% by weight. melting point is 180
~215℃. According to the method of the present invention, reinforced polybutadiene rubber can be continuously produced which exhibits excellent physical properties when made into a final rubber product. Next, examples and comparative examples will be shown. In the description of the examples, the boiling n-hexane insoluble portion of the reinforced polybutadiene rubber was determined by dissolving 2 g of the reinforced polybutadiene rubber in 200 ml of n-hexane at room temperature,
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.
- It was determined by evaporating hexane, drying it under vacuum, and accurately weighing it. In addition, the boiling n-hexane soluble content of the reinforced polybutadiene rubber and the cis-
1,4 structure content is infrared absorption spectrum (IR)
1,2 of boiling n-hexane insoluble fraction
-Structural content is determined by nuclear magnetic resonance spectrum (NMR)
The melting point of the boiling n-hexane insoluble fraction 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 rubber and the intrinsic viscosity [η] of the polybutadiene after cis-1,4 polymerization are the values measured in toluene at 30°C. Ring element viscosity η _SP /C of hexane-insoluble matter
The values are measured in tetralin at 135°C. Further, the content of carbon disulfide in the solution was measured and calculated using a gas chromatography equipped with a flame photometric detector manufactured by Hitachi, Ltd. using Chromosolve 102 as a filler. Example 1 Water was removed from a benzene solution containing 25.9% by weight of 1,3-butadiene and 11 mg of carbon disulfide using a dehydration tower, and water was added to the resulting solution.
After adding at a rate of 38 mg (1.9 mmol), they were mixed and dissolved in a mixing tank equipped with stirring blades. This solution was fed at a rate of 52/hour to a mixing tank with an internal volume of 20 and equipped with stirring blades, and 25.7 g (214 mmol) of diethylaluminium monochloride was mixed in/hour and mixed at 35° C. for 25 minutes (average residence time). The obtained aged liquid is −
After cooling to 5°C, a stainless steel autoclave with an internal volume of 20 mm and a ribbon-type stirring blade was used, and the outer cylinder was equipped with a jacket for temperature control, and an aqueous CaCl ₂ solution at -10°C was circulated through the jacket. 4. Cobalt octoate was fed to the polymerization tank at a rate of 52 g/hour, 328 mg/hour of cobalt octoate, 61.3 g/hour of 1,5-cyclooctadiene, and 6.7 g/hour of diuralyl-3,3'-thiodipropionate. cis-1,3-butadiene at a temperature of 50°C and an average residence time of 23 minutes.
1,4 polymerization occurred. 1 due to this cis-1,4 polymerization
The amount of polybutadiene produced per hour is 4.0Kg,
This polybutadiene has a cis-1,4 structure content of 97% or more, [η] (intrinsic viscosity, 30°C, in toluene) of 1.9, and a gel content of 0.01% as measured using a 200-mesh wire mesh. It was below. The polymerization reaction mixture obtained in the cis-1,4 polymerization tank was transferred to a polymerization tank of the same type as the cis-1,4 polymerization tank (however, the ribbon-type stirring blade was further equipped with a scraper for scraping). 52 per hour in certain 1 and 2 polymerization tanks
1,3-butadiene at 35°C at 2.5 g/hour, triethylaluminum at 30.2 g/hour,
312 mg of cobalt octoate was fed per hour, and 1,3-butadiene was 1,2-polymerized with stirring at a speed of 110 rpm at a polymerization temperature of 54 DEG C. and an average residence time of 22 minutes. The obtained polymerization reaction mixture was continuously supplied to a mixing tank equipped with stirring blades, and tris(nonylphenyl)phosphite (TNP) was added thereto in twice the mole of cobalt octoate, and a small amount of water was added to carry out polymerization. It stopped. This mixture is transferred to a solvent evaporation tank (steam stripper) equipped with stirring blades at a rate of 120% per hour.
The mixture was dispersed in ^the hot water and the solvent was evaporated. After extracting the slurry from the evaporation tank and separating water and dispersed polybutadiene crumbs, the crumbs were vacuum-dried at room temperature to obtain reinforced polybutadiene rubber. Polymerization was carried out continuously for 30 hours to obtain reinforced polybutadiene rubber weighing an average of 4.6 kg per hour of polymerization time (average residence time). This reinforced polybutadiene rubber has a boiling n-hexane insoluble content of 10.2%, and this boiling n-hexane insoluble content has a melting point of 206°C.
Reduced viscosity η _SP /C (135°C, in tetralin) is 2.7
(dl/g), and the 1,2-structure content is 92.9%.
and the boiling n-hexane soluble content is cis-1,4
The structural content was 97.0%, and [η] was 2.1. After the polymerization reaction was completed, a benzene solution of 1,3-butadiene was flowed for 30 minutes at a rate of 50% per hour, and the polymer adhering to the stirring blades and inner walls of the polymerization tank was scraped off, and the polymer was vacuum-dried to obtain the adhering polymer. Ta. The amount of attached polymer is
The amount was 18 g (of which 3 g was gel), and 98 g in the 1st and 2nd polymerization tanks. Example 2 Each component was added to the 1,2 polymerization tank in the same manner as in Example 1, except that triethylaluminum was added and mixed with 1,3-butadiene and then supplied to the 1,2 polymerization tank. The results are summarized in Table 1. Example 3 1,2 The amount of each component added to the polymerization tank was 1,2.
The procedure was carried out in the same manner as in Example 2, in which 3-butadiene was fed at 1.5 g/hour, triethylaluminum at 30.8 g/hour, and cobalt octoate at 411 mg/hour into the 1,2 polymerization tank. The results are summarized in Table 1. Example 4 1,2 A mixed solution obtained by adding and mixing a portion of triethylaluminum (1.5 times the mole of cobalt octoate) and cobalt octoate to 1,3-butadiene to be added to the 1,2 polymerization tank was The same procedure as in Example 1 was carried out except that the mixture was supplied to the double polymerization tank. The results are summarized in Table 1. Example 5 After adding and mixing triethylaluminum to 1,3-butadiene, the mixture was cooled to -10°C.
The same procedure as in Example 2 was carried out except that the amount of cooling water supplied to the 2nd polymerization tank and the 1st and 2nd polymerization tanks was reduced. The results are summarized in Table 1. Comparative Example 1 Carbon disulfide was supplied to a 1,2 polymerization tank, and 1,3-
The same procedure as in Example 1 was carried out except that butadiene was not supplied. The results are summarized in Table 1. 【table】

Claims (1)

[Claims] 1 cis-1,4 polymerization of 1,3-butadiene,
In the method of subsequent 1,2 polymerization, 1,3-butadiene, an inert organic solvent, and an inert organic solvent containing carbon disulfide in an amount of 20 mmol or less and water in an amount of 0.2 to 5 mmol per 1 total amount thereof. In a solvent solution, 1,3-butadiene is polymerized in the presence of a cis-1,4 polymerization catalyst containing a cobalt compound as one component to produce cis-1,4 polybutadiene, and the resulting polymerization reaction mixture is , the polymerization reaction mixture
1 to 50 parts by weight of 1,3-butadiene per 100 parts by weight is added, and the general formula AlR ₃ which is a component of the 1,2 polymerization catalyst other than the carbon disulfide (wherein R is a carbon number of 1 to 6 an alkyl group, phenyl group or cycloalkyl group), and optionally 1,
1,3-butadiene is 1,2-polymerized by adding a cobalt compound, which is another component of the 2-polymerization catalyst,
Boiling n-hexane insoluble matter 5-30% by weight and boiling n-
A method for producing reinforced polybutadiene rubber, which comprises producing a final polybutadiene rubber having a hexane soluble content of 95 to 70% by weight. 2. The method for producing reinforced polybutadiene rubber according to claim 1, wherein the 1,3-butadiene and the organoaluminum compound to be added to the polymerization reaction mixture are mixed in advance. 3. The method for producing reinforced polybutadiene rubber according to claim 1, characterized in that 1,3-butadiene, a part of the organoaluminum compound, and a cobalt compound to be added to the polymerization reaction mixture are mixed in advance. . 4. The method for producing reinforced polybutadiene rubber according to claims 1 to 3, wherein the 1,3-butadiene added to the polymerization reaction mixture is cooled in advance to 0° C. or lower. 5. The 1,2 polymerization of 1,3-butadiene is carried out in two stages, prepolymerization and main polymerization, and the 1,2 polymerization catalyst is added in the prepolymerization. A method for producing reinforced polybutadiene rubber according to items 1 to 4.