JPH0356567B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to an improved method for making reinforced 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 form cis-1,4-polybutadiene, and the polymerization system is then treated with a cobalt compound and a general A known method is to polymerize 1,3-butadiene in the presence of a 1,2 polymerization catalyst obtained from an organoaluminum compound represented by the formula _AlR3 (where R is the same as above) and carbon disulfide. (Special Publication No. 17666, Showa 49). The above method uses an organoaluminum compound represented by the general formula _AlR3 as the aluminum component of the 1,2-polymerization catalyst, and can produce reinforced polybutadiene with excellent physical properties; It has the disadvantage of low catalyst activity. As a result of research aimed at improving the above polymerization method, the present inventors found that AlR ₃ was used instead of AlR ₃ .
The general formula AlR ₃ xMOH is a reaction product of AlR ₃ and NaOH or LiOH obtained by mixing an inert solvent solution of
are the following numbers, R is an alkyl group, phenyl group, or cycloalkyl group having 1 to 8 carbon atoms,
If an organoaluminum estimated to be represented by M is Na or Li] is used, the activity of the 1,2 polymerization catalyst will be high even if the amount of AlR ₃ used is small;
High melting point, high molecular weight syndiotactic 1,2-
It was discovered that 1,2 polymerization to give polybutadiene progresses, and the present invention was completed. That is, the present invention discloses that a soluble cobalt compound and a compound of the general formula _{AlR o} 1,3-butadiene is polymerized in the presence of a cis-1,4 polymerization catalyst obtained from a halogen-containing organoaluminum compound represented by to produce cis-1,4 polybutadiene, and then add a soluble cobalt compound, the halogen-containing organoaluminum compound, and an organoaluminum represented by the general formula AlR ₃ (where R is the same as above) to this polymerization system. 1, obtained from a reaction product of a compound with sodium hydroxide or lithium hydroxide and carbon disulfide or phenyl isothiocyanate.
Polymerizing 1,3-butadiene in the presence of a bipolymerization catalyst to produce a final polybutadiene having a boiling n-hexane insoluble content of 4 to 30% and a boiling n-hexane soluble content of 96 to 70%. The present invention relates to a method for producing reinforced polybutadiene. According to the method of this invention, it is possible to reduce the amount _of expensive AlR ₃ used, which is a component of the 1,2 polymerization catalyst. Therefore, the invention of this application has important industrial significance.In the method of this invention, the soluble cobalt component of the cis-1,4-polymerization catalyst The cobalt compound may be any cobalt compound as long as it is soluble in the polymerization solvent used. For example, such a soluble cobalt compound may include a β-diketone complex of cobalt or a β-keto acid ester of cobalt. Complexes are preferably used.As the β-diketone of the ligand of these cobalt complexes, 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). (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are the same as above). Particularly preferred complexes are cobalt () acetylacetonate, cobalt () acetylacetonate, and cobalt acetoacetic acid ethyl ester complexes. Further, as the soluble 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 soluble cobalt compound, for example, a halogenated cobalt complex, that is, a general formula CoXn.Ym (wherein, X is a halogen atom, particularly preferably a chlorine atom, n is an integer of 2 or 3, and Y is a and m is an integer of 1 to 4) can also be suitably used. In the above formula, any ligand known to form a complex with cobalt halide as a ligand,
For example, amines such as pyridine, triethylamine, tributylamine, dimethylaniline, alcohols such as methyl alcohol, ethyl alcohol, and N,N-dimethylformamide, N,N-
Examples include N,N-dialkylamide such as dimethylacetamide and N,N-diethylformamide. Particularly preferred cobalt halide complexes include cobalt chloride pyridine complexes,
Mention may be made of cobalt chloride ethyl alcohol complex. Furthermore, examples of soluble cobalt compounds include tris-π-allyl cobalt, bis-acrylonitrile-π-allyl cobalt, bis-π-1,5
-cyclooctadiene-tert-butylisonitrile cobalt, π-cyclooctenyl-π-1,5-
Cyclooctadiene cobalt, π-1,3-cycloheptadienyl-π-1,5-cyclooctadiene cobalt, bicyclo-[3,3,0]-octadienyl-1,5-cyclooctadiene cobalt, bis- (π-allyl) halogen cobalt (however, the halogen atom is selected from chlorine, bromine, and iodine), bis-(π-1,5-cyclooctadiene) ethyl cobalt, (1,3-butadiene) [ Cobalt complexes of olefins and diolefins such as 1-(2-methyl-3-butenyl)-π-allyl]cobalt can also be suitably used. In the method of the present 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 medium 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, xylene, etc. group hydrocarbons, n-heptane, n-hexane, etc., aliphatic hydrocarbons, alicyclic hydrocarbons such as cyclohexane, and their halides, such as chlorobenzene, 0-dichlorobenzene, methylene chloride, 1,2-dichloroethane , 1,1,2-trichloroethane, and the like. 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 preferably in the range of 10 minutes to 5 hours. Further, the concentration of 1,3-butadiene in the reaction system during cis-1,4 polymerization may be in the range of 5 to 40% by weight based on the total polymerization solution. The above cis-1,4 polymerization has a cis-1,4 structure content of 90% or more, especially 95% or more, and an intrinsic viscosity [η] (measured in toluene at 30°C) of 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 an appropriate value, known molecular weight regulators, such as
Non-conjugated dienes such as cyclooctadiene (hereinafter abbreviated as COD), arenes, 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, and 1,3-butadiene is 1,2 polymerized. . 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 above-mentioned cis-1,4 polymerization catalyst. As the organoaluminum halide which is the aluminum component of the 1,2 polymerization catalyst, the same one as the aluminum component of the cis-1,4 polymerization catalyst described above can be used. If these components are added in the amount necessary for 1,2 polymerization at the time of cis-1,4 polymerization, 1,2
Addition during polymerization can be omitted. Organoaluminium, which is the other aluminum component of the 1,2 polymerization catalyst; AlR ₃ x MOH [however, x
is a number less than or equal to 1, and M is Na or Li]
is a solution of AlR ₃ in an inert solvent (randomly selected from the polymerization solvents mentioned above for the polymerization solvent solution of 1,3-butadiene) and an equimolar or less amount of AlR ₃ .
It is obtained by dissolving and mixing NaOH or LiOH (solid). AlR ₃ mentioned above
R is an alkyl group, phenyl group, or cycloalkyl group having 1 to 8 carbon atoms, and _AlR3 is triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-hexylaluminum, tri-n-hexylaluminum, tri-n-hexylaluminum, tri-n-hexylaluminum, Examples include cyclohexylaluminum. The preparation of the AlR ₃ xMOH solution is described in detail in Catalysts, Vol. 7, 37 (1965). The molar ratio between MOH and _AlR3 is preferably 0.01 to 0.5, particularly preferably 0.1 to 0.35. In the method of this invention, carbon disulfide or phenyl isothiocyanate, preferably carbon disulfide, is used as the 1,2 polymerization catalyst component. 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%, AlR3 .} preferable. In addition, the amount of organoaluminum halide is 10% per mole of soluble cobalt compound.
~500 mol, especially 20-200 mol is preferred,
The concentration of organoaluminum represented by AlR ₃ xMOH is preferably used at a concentration equal to or higher than the mole of water in the polymerization system per AlR ₃ , and should be at most 1.5 times the mole of the total amount of water and organoaluminium halide. is preferred. The amount of carbon disulfide or phenyl isothiocyanate is 0.1 per mole of soluble cobalt compound.
~500 mol, especially 1-500 mol is preferred. There are no particular restrictions on the order or method of adding 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 8, it can also be added in advance before cis-1,4 polymerization. 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 preferably in the range of 10 minutes to 5 hours. . 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 to be subjected to polymerization is cis-
It may be added in the 1,4 polymerization step, or 1,3-butadiene and/or a portion of the solvent may be added in the cis-1,4 polymerization step of 1,3-butadiene, and then added in the 1,2 polymerization step. At , the remaining amount of 1,3-butadiene and/or solvent may be added. At this time, 1 in the reaction system,
The concentration of 3-butadiene is 3 to 3 with respect to the total polymerization solution.
A range of 40% by weight is preferred. The method of the present invention can also be carried out in batch mode by carrying out cis-1,4 polymerization and subsequent 1,2 polymerization in the same reaction vessel, or 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 and subsequent 1,2 polymerization in the same reaction vessel as a batch method. It can also be carried out industrially by continuously polymerizing 1,3-butadiene in a 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 4 to 30% and a boiling n-hexane soluble content of 96 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 a polar solvent containing acid, organic acids such as acetic acid or benzoic acid, monoethanolamine or 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 4 to 30%, and the boiling n-hexane insoluble fraction (HI). Hexane soluble content is 96-70%. Preferably, the boiling n-hexane soluble fraction has an intrinsic viscosity ([η]) (measured at 30°C in toluene) of 1 to 5, a cis-1,4 structure content of 92% or more, and a boiling n-hexane soluble content. The intrinsic viscosity ([η]) of the n-hexane insoluble portion (measured at 135℃ 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
-Hexane-insoluble matter is obtained by dissolving 2 g of reinforced polybutadiene 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 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 ( 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. Preparation example of AlEt ₃・0.2NaOH Place a stirrer piece in a 200ml Erlenmeyer flask with a three-way stopcock, replace the inside with nitrogen, and then pulverize 0.400g (10 mmol) of NaOH in a dry box.
I put it in. 92.6 ml (50 mmol of triethylaluminum) of a benzene solution of triethylaluminum (concentration 0.54 mmol/ml) was added, and the mixture was reacted at room temperature with stirring. The NaOH dissolved rapidly to give a homogeneous, transparent, colorless solution. Example 1 85 g of dried 1,3-butadiene was dissolved in 860 ml of dehydrated benzene and 1, Add a benzene solution of 3-butadiene (containing 10 mmol of water), and while keeping the liquid temperature at 40°C, add 4.6 mmol of cyclooctadiene, 4.0 mmol of diethylaluminum monochloride, and cobalt octoate to the benzene solution of 1,3-butadiene (containing 10 mmol of water). After sequentially adding 0.043 mmol with stirring, 1,3-butadiene was cis-1,4 polymerized at 40° C. for 10 minutes with continued stirring. The polymer had a cis-1,4 structure content of 96% or more and [η] of 2.4.
Immediately after the cis-1,4 polymerization, 1.4 mmol of a benzene solution of AlEt ₃ 0.2NaOH and 0.13 mmol of carbon disulfide were added per AlEt ₃ , and then 1,3-butadiene was added at 40°C for 16 minutes with stirring. , 2 polymerized. A small amount of 2,
The polymerization reaction was stopped by adding 1 methanol containing 6-di-tert-butyl-4-methylphenol and hydrochloric acid. Collect the precipitated polymer, about 40
It was dried under reduced pressure at °C to obtain 60.5 g of polybutadiene. This polybutadiene contains 14.7% of boiling n-hexane insoluble matter, and 14.7% of boiling n-hexane insoluble matter.
2 structure content is 93.0%, melting point is 205℃, intrinsic viscosity ([η]) is 3.8, and cis-1,4 structure content in boiling n-hexane soluble content is 96.4%.
and the intrinsic viscosity ([η]) (toluene, 30℃) is
It was 2.2. Examples 2 to 4, Comparative Examples 1 to 3 Examples 2 to 4 were carried out in the same manner as in Example 1 except that AlEt ₃ .0.2NaOH was varied. AlEt the result ₃
It is shown in Table 1 along with a comparative example using only

[Table] Examples 5 to 7, Comparison Column 4 In Examples 5 to 7, polymerization was carried out in the same manner as in Example 1 except that the types of x and M of AlEt ₃ xMOH and the organic aluminum used in the polymerization were changed. The results are shown in Table 2 along with a comparative example using AlEt ₃ .

[Table] Example 8 Polymerization was carried out in the same manner as in Example 1 except that the addition position of 0.13 mmol of carbon disulfide was changed to immediately after the addition of cyclooctadiene. Polybutadiene yield 61.0g, boiling n
-Hexane insoluble content is 12.7%, its intrinsic viscosity
3.4, the melting point was 205°C. The n-hexane soluble content had a cis-1,4 structure content of 96.3% and an intrinsic viscosity of 2.3.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a method for producing reinforced polybutadiene according to claim 1.

Claims (1)

[Scope of Claims] 1 In a polymerization solvent solution of 1,3-butadiene, a soluble cobalt compound and a compound of the general formula _{AlR o} 1,3-butadiene in the presence of a cis-1,4 polymerization catalyst obtained from a halogen-containing organoaluminum compound represented by Polymerization is performed to produce cis-1,4 polybutadiene, and then a soluble cobalt compound, the halogen-containing organoaluminum compound, and an organic compound represented by the general formula AlR ₃ (where R is the same as above) are added to the polymerization system. 1,3-butadiene is polymerized in the presence of a reaction product of an aluminum compound and sodium hydroxide or lithium hydroxide and a 1,2-polymerization catalyst obtained from carbon disulfide or phenyl isothiocyanate, and boiling n-hexane insoluble matter is removed. is 4-30
%, producing a final polybutadiene having a boiling n-hexane soluble content of 96 to 70%.