JPH0262123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing reinforced polybutadiene comprising 5 to 30% by weight of boiling n-hexane insolubles and 95 to 70% by weight of boiling n-hexane insolubles. Cis-1,4 polybutadiene obtained by polymerizing 1,3-butadiene in the presence of a cis-1,4 polymerization catalyst is produced in large quantities as a raw material for tires and other rubber products. The physical properties of rubber products obtained from cis-1,4 polybutadiene are superior to products made from natural rubber, especially in terms of good impact resilience, low calorific value, and superior abrasion resistance. This superiority is one of the reasons why cis-1,4 polybutadiene is used in large quantities. However, cis-1,4 polybutadiene has the disadvantage that the rubber products obtained therefrom have low tear strength and low flex crack growth resistance. As a polybutadiene that improves the drawbacks of this cis-1,4 polybutadiene, 1,3-butadiene is polymerized in the presence of a cis-1,4 polymerization catalyst to produce cis-1,4 polybutadiene, and then 1,3-butadiene is produced. A new polybutadiene obtained by polymerizing 1,3-butadiene in the presence of a dipolymerization catalyst has been proposed (Japanese Patent Publication No. 17666/1983). The above publication describes an experimental example of producing polybutadiene which, when vulcanized, has high tear strength and excellent flex crack growth resistance. However, the method for producing polybutadiene described in the above publication uses carbon disulfide as a component of the 1,2 polymerization catalyst, and this carbon disulfide is added to the 1,2 polymerization tank. After the reaction is complete, it is difficult to completely separate carbon disulfide from 1,3-butadiene and an inert organic solvent, especially from 1,3-butadiene by distillation. When it comes into contact with a halogen-containing organoaluminum compound, especially in the coexistence of a cobalt compound, side reactions are likely to occur, and the side reaction products produced in this side reaction are cis-1,4 polymerization of 1,3-butadiene. Because it significantly inhibits
Carbon disulfide is difficult to handle, and furthermore, 1,
During 2-polymerization, scale adheres to the inside of the polymerization vessel, making it difficult to remove heat, making it difficult to control the polymerization temperature, and disrupting the 1- and 2-polymerization reactions, making it difficult to obtain reinforced polybutadiene of stable quality. Therefore, it has been difficult to put the production of polybutadiene into practical use. Therefore, the inventors completed this invention as a result of intensive research aimed at providing a continuous production method for polybutadiene having the above-mentioned excellent physical properties. That is, this invention involves cis-1,4 polymerization of 1,3-butadiene in an inert organic solvent solution,
In the subsequent 1,2 polymerization method, 1,3-butadiene is cis-copolymerized in an inert organic solvent solution containing an inert organic solvent and carbon disulfide in an amount of 20 mmol or less per total amount of these. 1,3-butadiene is polymerized in the presence of a 1,4 polymerization catalyst to produce cis-1,4 polybutadiene, and a 1,2-polymerization catalyst other than the carbon disulfide is added to the resulting polymerization reaction mixture. One component is an organoaluminum compound represented by the general formula AlR ₃ (where R is an alkyne group, phenyl group, or cycloalkyl group having 1 to 6 carbon atoms), water, and optionally a 1,2 polymerization catalyst. 1,3-butadiene is 1,2-polymerized by adding a cobalt compound as one component, and 5 to 30% by weight of boiling n-hexane insolubles and 95 to 70% of boiling n-hexane solubles are added. After adding a polymerization terminator to the resulting polymerization reaction mixture to stop the polymerization of 1,3-butadiene, the solid content of polybutadiene is separated and obtained, and the remaining unreacted 1,3-butadiene is separated and obtained. From a mixture containing 3-butadiene, an inert organic solvent, and carbon disulfide, without separating carbon disulfide and 1,3-butadiene or the inert organic solvent by distillation,
The present invention relates to a method for producing reinforced polybutadiene, characterized in that 1,3-butadiene, an inert organic solvent, and carbon disulfide are obtained as fractions. According to the method of this invention, 1, 2 polymerization,
2-Polybutadiene (insoluble in boiling n-hexane)
The yield of polymer (reinforced polybutadiene) 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. Since it is not necessary to separate the carbon sulfide from the 1,3-butadiene and the inert organic solvent, these mixtures can be recycled and used. In addition, the concentration of carbon disulfide has already become uniform at the entrance of the 1,2 polymerization tank, and furthermore, the 1,2 polymerization reaction system can be activated by combining it with an organoaluminum compound, which is a component of the 1,2 polymerization catalyst. Because the Lewis acidity is adjusted to a suitable level, the polymerization reaction of 1,3-butadiene by the 1,2 polymerization catalyst becomes uniform and highly active, reducing the amount of polymer deposited in the 1,2 polymerization tank and allowing continuous Operation time can be extended. In the method of the present invention, first, 1,3-butadiene and an inert organic solvent are used in a ratio of 20 mmol or less, preferably 0.01 to 10 mmol, per 1 total amount of the 1,3-butadiene and inert organic solvent. It is necessary to mix it with carbon disulfide in a proportion of .
Even if the amount of carbon disulfide, which is a component of the 1,2 polymerization catalyst, to be mixed is greater than the above amount, the polymerization activity of the 1,2 polymerization catalyst will not improve, but rather the amount of recovered carbon disulfide will increase. Undesirable. As the inert organic solvent, cis-1,4
There is no particular restriction as long as the organic solvent can dissolve polybutadiene, but aromatic hydrocarbons such as benzene, toluene, and xylene, aliphatic hydrocarbons such as n-heptane and n-hexane, and alicyclic solvents such as cyclohexane and cyclopentane are used. group hydrocarbons, and their halides, such as methylene chloride, chlorobenzene, and the like. 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 3 to 40.
Preferably, it is % by weight. In addition, in the method of the present invention, in the mixed liquid obtained as described above, 0.5 to
Preferably, water is contained in a concentration of 5 mmol. As a method to adjust the concentration of water,
A method known per se can be employed. In the method of this invention, in the inert organic solvent solution obtained as described above, cis-1,4
1,3-butadiene is polymerized in the presence of a polymerization catalyst to produce cis-1,4 polybutadiene. The above-mentioned cis-1,4 polymerization catalyst is not particularly limited, and for example, a cis-1,4 polymerization catalyst obtained from a cobalt compound and a halogen-containing organic aluminum compound is
A cis-1,4 polymerization catalyst containing a cobalt compound as one component, such as a 1,4 polymerization catalyst, and a boron trifluoride complex compound such as a nickel compound and boron trifluoride or boron trifluoride-dialkyl etherate. Examples include cis-1,4 polymerization catalysts containing a nickel compound as one component, such as cis-1,4 polymerization catalysts obtained from trialkylalumium, preferably cis-1,4 polymerization catalysts containing a cobalt compound as one component.
Examples include polymerization catalysts. Any cobalt compound may be used as long as it is soluble in the inert organic solvent used. For example, such cobalt compounds include cobalt () acetylacetonate,
Cobalt β-diketone complexes such as cobalt () acetylacetonate, cobalt β-keto acid ester complexes such as cobalt acetoate ethyl ester complex, cobalt octoate, cobalt naphthenate, cobalt benzoate, etc. Cobalt salts of organic carboxylic acids, cobalt chloride pyridine complexes, cobalt halide complexes such as cobalt chloride ethyl alcohol complexes, and the like can be mentioned. Examples of the halogen-containing organoaluminum compound include diethylaluminum monochloride, diethylaluminum monobromide, diisobutylaluminum monochloride, and ethylaluminum sesquichloride. In the method of this invention, the amount of the cis-1,4 polymerization catalyst containing a cobalt compound as one component is as follows:
0.1 mmol or more of a halogen-containing organoaluminum compound per 1 mole of 1,3-butadiene,
It is particularly preferable that the amount of the cobalt compound is 0.5 to 50 mmol, and 0.005 mmol or more, especially 0.01 mmol or more. Further, the molar ratio (Al/Co) of the halogen-containing organoaluminum compound to the cobalt compound is preferably 5 or more, particularly 15 or more. 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 either normal pressure or increased pressure, and the polymerization time (average The residence time (residence time) varies depending on the catalyst concentration, monomer concentration, polymerization temperature, etc., but is generally preferably in the range of 10 minutes to 10 hours. 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,
Or an a-olefin 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 in the cis polymerization step, cis-1,
A cobalt compound, a general formula
An organoaluminum compound represented by AlR ₃ and water were added, and the resulting solution was stirred and mixed.
Polymerize 3-butadiene to obtain a boiling n-hexane insoluble content of 5 to 30% by weight and a boiling n-hexane soluble content of 95 to 70% by weight.
% by weight of reinforced polybutadiene. General formula AlR ₃ , which is a component of 1,2 polymerization catalyst
The organoaluminum compound represented by
Examples include triethylaluminum, trimethylaluminum, tributylaluminum, trinormalhexylaluminum, and triphenylaluminum. In the method of this invention, when the cobalt compound of the cis-1,4 polymerization catalyst and the cobalt compound of the 1,2 polymerization catalyst are the same, during cis polymerization,
It is also possible to add the cobalt compound in the required amount for the 1,2 polymerization, and only add the organoaluminum compound and water during the 1,2 polymerization. The organoaluminum compound and water may be reacted in advance and then added to the 1- and 2-polymerizer, but it is preferable to add them separately. Water, which is a component of the 1,2 polymerization catalyst, may be added after being dissolved in either an inert organic solvent, 1,3-butadiene, or a mixed solution thereof. Examples of the cobalt compound for the 1,2 polymerization catalyst include the same ones as for the cis-1,4 polymerization catalyst described above. The amount of the 1,2 polymerization catalyst used varies depending on the type and combination of catalyst components and polymerization conditions, but the amount of cobalt compound per mole of 1,3-butadiene is 0.005 mmol or more, particularly 0.01 to 5 mmol,
Preferably, the organoaluminum compound is at least 0.1 mmol, especially from 0.5 to 50 mmol, the water is at least 0.01 mmol, especially from 0.1 to 35 mmol, and the carbon disulfide is at least 0.001 mmol, especially from 0.005 to 10 mmol. Furthermore, the amount of water added should be 0.1 to 0.8 times the mole of the organoaluminum compound, especially 0.2 to 0.7
Double molar ratio is preferred. In the method of this invention, the polymerization temperature for 1,2 polymerization is preferably -20 to 80°C, particularly 5 to 60°C, the polymerization pressure may be normal pressure or increased pressure, and the polymerization time is 10 minutes to 10 hours. A range of is preferred. Also,
The solution is stirred and mixed in a 1,2 polymerization reactor. As a 1,2 polymerization reactor used for 1,2 polymerization, the viscosity of the polymerization reaction mixture becomes very high during 1,2 polymerization, and the polymer tends to adhere to the inside of the polymerization reactor, so Japanese Patent Publication No. 40-2645 It is preferable to use a polymerization tank equipped with a scraping member as described in . During 1,2 polymerization, the concentration of 1,3-butadiene in the polymerization system is preferably 3 to 35% by weight. In the method of the present invention, cis-1,4 polymerization of 1,3-butadiene is followed by 1,2 polymerization, and the resulting polybutadiene contains carbon disulfide, a cobalt compound, an organoaluminum compound, and an inert organic A polymerization terminator is added to a polymerization reaction mixture containing a solvent to terminate polymerization, and then polybutadiene as a solid content is separated and obtained. Examples of the polymerization terminator include alcohols, acids, amines, phosphoric esters, and the like. The polybutadiene obtained by the method of this invention has a content insoluble in boiling n-hexane of 5 to 30% by weight, a content insoluble in boiling n-hexane of 95 to 70% by weight, and a melting point of the content insoluble in boiling n-hexane. is 180~215
It is ℃. In the method of the present invention, the solid content of polybutadiene is added to a precipitant such as methanol or flashed from the final polymerization reaction mixture in which the polymerization has been stopped after the 1, 2 polymerization reaction, and the remainder is separated and obtained. From a mixture containing unreacted 1,3-butadiene, an inert organic solvent and carbon disulfide, commonly known as a recovery solvent, by distillation, e.g.
1,3-butadiene containing most of carbon disulfide is obtained as a fraction by the first distillation column, and the second distillation is carried out from the bottom of the first distillation column containing an inert organic solvent. Carbon disulfide and the other two components,
In particular, without separating 1,3-butadiene,
The 1,3-butadiene containing carbon disulfide and the inert organic solvent are obtained as a fraction, mixed with fresh 1,3-butadiene make-up and reused. According to the method of the present invention, reinforced polybutadiene 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 Examples and Comparative Examples, boiling n-hexane-insoluble components of reinforced polybutadiene are extracted by dissolving 2 g of reinforced polybutadiene in 200 ml of n-hexane at room temperature, and then extracting the insoluble components using a Soxhlet extractor for 4 hours. The extraction residue was then vacuum-dried and its weight was precisely weighed. In addition, the boiling n-hexane soluble content is obtained by evaporating n-hexane from the n-hexane soluble content obtained as above and extracting it using a Sosclay extractor, and then vacuum drying and weighing the weight accurately. This is what I asked for. In addition, the n-hexane soluble content of reinforced polybutadiene and the cis-1,4 of polybutadiene after cis-1,4 polymerization
The structural content was measured by infrared absorption spectrum (IR), the 1,2-structure content of the n-hexane insoluble part was measured by nuclear magnetic resonance spectroscopy (NMR), and the melting point of the n-hexane insoluble part was determined by the self-recorded difference. It was determined by the peak temperature of the endothermic curve measured by a dynamic calorimeter (DSC). In addition, the intrinsic viscosity [η] of the n-hexane soluble content of the reinforced polybutadiene and the polybutadiene after cis-1,4 polymerization are the values measured in toluene at 30°C, and the n-hexane insoluble content of the reinforced polybutadiene is the value measured in toluene at 30°C. For reduced viscosity η _SP /C, 135
℃, measured in tetralin. 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 Co., Ltd. and using Chromosolve 102 as a filler. Example 1 Water was removed from a benzene solution containing 23.7% 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 (2.1 mmol), they were mixed in a mixing tank equipped with stirring blades and dissolved. After cooling this solution to -3°C, a stainless steel autoclave with an inner volume of 20 mm and equipped with ribbon-type stirring blades was equipped with a jacket for temperature control on the outer cylinder, and a CaCl ₂ aqueous solution at -10°C was circulated through the jacket. The cis-1,4 polymerization tank was supplied with 25.0 g of diethylaluminum monochloride, 60.0 g of 1,5-cycloocdiene per hour, and TRL (dilauryl-
3,3′-thiodipropionate) 7.0 g/hour,
255 mg of cobalt octoate was supplied per hour, and 1,3-butadiene was cis-1,4 polymerized with stirring at a polymerization temperature of 40° C. and an average residence time of 24 minutes. The amount of polybutadiene produced per hour by this cis-1,4 polymerization is 3.20 kg, and this polybutadiene has a cis-1,4 structure content of 97% or more, [η] of 1.8, and a 200-mesh polybutadiene. The gel content measured using a wire mesh was 0.02%. The polymerization reaction mixture obtained in the cis-1,4 polymerization tank is continuously fed at a rate of 50% per hour to the 1,2 polymerization tank, which is the same type of polymerization tank as the cis-1,4 polymerization tank. 27.5g of ethylene aluminum/hour, 2.69g of water/hour, cobalt octoate/hour
813mg was supplied, and 1,3-butadiene was added to 1,3-butadiene with stirring at a polymerization temperature of 40°C and an average residence time of 24 minutes.
Double polymerization occurred. The obtained polymerization reaction mixture was continuously supplied to a mixing tank equipped with stirring blades, and 2,6-di-tert-butyl-4-methylphenol was added to the rubber.
1 PHR was added and a small amount of methanol was added to stop the polymerization. This mixture was supplied to a solvent evaporation tank (steam stripper) equipped with stirring blades at a rate of 120 per hour, hot water and saturated steam of 4 kg/cm ² G were supplied, the mixture was dispersed in the hot water, and the solvent was evaporated. I let it happen. After extracting the slurry from the evaporation tank and separating water and dispersed polybutadiene (crumb), the crumb was vacuum-dried at room temperature to obtain reinforced polybutadiene. Polymerization was carried out continuously for 16 hours, yielding an average of 3.89 kg of reinforced polybutadiene per hour of polymerization time. This reinforced polybutadiene has a boiling n-hexane insoluble content of 17.8% by weight, a boiling n-hexane insoluble content having a melting point of 206°C, η _SP /C of 3.0 (dl/g), and a 1,2- The structural content was 9.32%, and the cis-1,4-structure content of the boiling n-hexane insoluble matter was 97.1%, and [η] was 1.8. 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 adhering polymer was 18 g (of which 6 g was gel) in the cis polymerization tank, and 6.7 g in the 1 and 2 polymerization tanks. On the other hand, the solvent evaporated from the evaporation tank is cooled and condensed to separate into an aqueous phase and a solvent layer, and then from the obtained solvent (referred to as recovered solvent), 1,3-butadiene, benzene, and disulfide are extracted as follows. Carbon was recovered. The above recovery solvent 600 containing 15.3% by weight of 1,3-butadiene and 13mg/carbon disulfide
High-boiling substances were removed by distillation to obtain a polymerization solvent, and the polymerization solvent was reused. Through the distillation, carbon disulfide, 1,3-butadiene, and benzene in the recovered solvent were recovered. Example 2 1, 2 The amount of water added to the polymerization tank is 2.00 per hour.
Example 1 was carried out in the same manner except that G, 1, and 2 were supplied to the polymerization tank. The results are summarized in Table 1. Example 3 Triethylaluminum and water to be added to the 1,2 polymerization tank were prepared in advance in separate containers at a reaction temperature of 30°C.
Example 1 was carried out in the same manner as in Example 1, except that the compound reacted at 40 minutes at an average residence time of 40 minutes was supplied to the 1 and 2 polymerization tank. The results are summarized and shown in Table 1. Example 4 The same procedure as Example 1 was carried out except that the polymerization temperature for 1,2 polymerization was 50°C. The results are summarized and shown in Table 1. Comparative Example 1 The same procedure as in Example 1 was carried out except that carbon disulfide was supplied to the 1,4 polymerization tank at a concentration of 11 mg/. The results are summarized in Table 1. 【table】

Claims (1)

[Claims] 1. A method of cis-1,4 polymerization of 1,3-butadiene in an inert organic solvent solution and then 1,2 polymerization, comprising: 1,3-butadiene, an inert organic solvent, and 1,3-butadiene is polymerized to produce polybutadiene in the presence of a cis-1,4 polymerization catalyst in an inert organic solvent solution containing carbon disulfide in an amount of 20 mmol or less per total amount of , Into the obtained polymerization reaction mixture, a compound of the general formula AlR ₃ which is a component of the 1,2-polymerization catalyst other than the carbon disulfide (wherein R is an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a cycloalkyl group) is added. 1,2-polymerize 1,3-butadiene by adding an organoaluminum compound represented by ), water, and optionally a cobalt compound that is another component of the 1,2 polymerization catalyst, A final polybutadiene consisting of 5 to 30% by weight of boiling n-hexane insolubles and 95 to 3% of boiling n-hexane insolubles is produced, and a polymerization terminator is added to the resulting polymerization reaction mixture to produce 1,3-butadiene. After the polymerization of the polybutadiene rubber is stopped, the solid content of polybutadiene rubber is separated and obtained, and from the mixture containing the remaining unreacted 1,3-butadiene, an inert organic solvent, and carbon disulfide, it is distilled to obtain dipropylene rubber. without separating carbon sulfide and 1,3-butadiene or inert organic solvent,
A method for producing reinforced polybutadiene, which comprises obtaining 1,3-butadiene, an inert organic solvent solution, and carbon disulfide as fractions.