JPH08325331A - Method for producing polybutadiene - Google Patents

Abstract

(57) [Summary] [Structure] (A) Cobalt compound, (B) Carbon disulfide,
A compound selected from the group consisting of phenyl isothiocyanate and a xanthate compound, (C) the general formula AlR ₃
(In the formula, R is a hydrocarbon group having 1 to 10 carbon atoms), and (D) an organoaluminumoxy compound is used as a catalyst to polymerize 1,3-butadiene. A method for producing polybutadiene, which is characterized in that [Effect] It is possible to provide a production method capable of obtaining highly crystalline 1,2-polybutadiene or a mixture of highly crystalline 1,2-polybutadiene and cis polybutadiene with high productivity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing polybutadiene by polymerizing 1,3-butadiene using a specific catalyst system.

[0002]

2. Description of the Related Art Polybutadiene having a syndiotactic 1,2-structure as a main structure (hereinafter referred to as "SPB") has a vinyl group in its side chain, and therefore has reactivity with other polymers and elastomers. Is expected to be high. Also, 1
It is known that a resin having a relatively high melting point of about 50 ° C. or higher is a tough resin. Therefore, SPB is expected to have a wide range of uses as a reinforcing material for various rubbers or as a raw material for polymer alloys.

Reinforcing polybutadiene, which is a mixture of SPB and cis polybutadiene, is widely used for tire applications and the like, and reinforcing polybutadiene having a high content of 1,2-structure is also expected for various rubber blending applications. ing.

SPB is produced by polymerizing 1,3-butadiene using a catalyst composed of a cobalt compound, a Group I to III organometallic compound, and carbon disulfide, for example, JP-B-47-19892. It is disclosed in Japanese Patent Publication No. 47-19893.

Further, there is known a method for producing a reinforced polybutadiene composed of cis polybutadiene and 1,2-polybutadiene by a two-step polymerization method of polymerizing 1,2-polybutadiene after cis polybutadiene polymerization. JP-A-58-168640 discloses a method of polymerizing 1,2-polybutadiene in a solution containing cis polybutadiene.

[0006]

The present invention has a high crystallinity.
An object of the present invention is to provide a production method capable of obtaining 1,2-polybutadiene or a mixture of highly crystalline 1,2-polybutadiene and cis polybutadiene with high productivity.

[0007]

The present invention provides (A) a cobalt compound, (B) a compound selected from the group consisting of carbon disulfide, phenyl isothiocyanate and a xanthate compound, and (C) a general formula AlR ₃ ( In the formula, R has 1 to 10 carbon atoms
Is a hydrocarbon group. The invention relates to a method for producing polybutadiene, which comprises polymerizing 1,3-butadiene using a catalyst composed of the organoaluminum compound represented by the formula (4) and the organoaluminumoxy compound (D).

The cobalt compound as the component (A) in the present invention includes an organic acid salt of cobalt, a complex compound, or a chloride. Specific examples include cobalt salts such as cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate, cobalt naphthenate, cobalt acetate and cobalt malonate, cobalt bisacetylacetonate and trisacetylacetonate, and ethyl acetoacetate. Examples include organic base complexes such as ester cobalt and cobalt halide pyridine complexes and picoline complexes, and ethyl alcohol complexes.

The component (B) of the present invention is a compound (hereinafter abbreviated as "carbon disulfide etc.") selected from the group consisting of carbon disulfide, phenylisothiocyanic acid and xanthogen.

The component (C) of the catalyst used in the present invention is
An organoaluminum compound represented by the general formula AlR ₃ (wherein R is a hydrocarbon group having 1 to 10 carbon atoms). Specific examples include trialkyl aluminum such as triethyl aluminum, tributyl aluminum and trioctyl aluminum.

The organoaluminum oxy compound of the component (D) of the catalyst used in the present invention has the general formula (-Al
A linear or cyclic polymer represented by (R ')-O-) _n (R' is a hydrocarbon group having 1 to 10 carbon atoms, and is partially substituted with a halogen atom and / or an R'O group. Including things.
n is the degree of polymerization, preferably 5 or more, more preferably
10 or more. ). Specific examples include methylalumoxane, ethylalumoxane, isobutylalumoxane, and the like, in which R ′ is a methyl, ethyl, or isobutyl group, respectively.

The ratio of each component of the catalyst of the present invention is preferably within the following range.

That is, the molar ratio of (B) to the component (A) is preferably 0.1 or more, and particularly preferably 0.5 or more.

The molar ratio of (C) to component (A) is
The range of 0.1 to 500 is preferable, and the range of 1 to 100 is particularly preferable.

The molar ratio of (D) to component (A) is
The range of 0.1 to 500 is preferable, and the range of 1 to 300 is particularly preferable.

The molar ratio of (D) to component (C) is
The range of 0.1 to 500 is preferable, and the range of 1 to 300 is particularly preferable. In the present invention, (D) to component (C)
When the molar ratio of is 10 or more, a mixture of SPB and cis polybutadiene is produced, and when the molar ratio of (D) to component (C) is less than 10, substantially only SPB is produced.

As the polymerization method in the production method of the present invention, a solution polymerization method, an emulsion polymerization method, a suspension polymerization method and the like can be used.
For example, the solution polymerization method can be carried out by the following procedure, for example. First, 1,3-butadiene is dissolved in a solvent, and this is supplied to a polymerization vessel equipped with a stirrer, which is replaced with an inert gas such as nitrogen. Then, a cobalt compound, carbon disulfide or the like which is a catalyst component, an organoaluminum compound, and an organoaluminum oxy compound are added as a solution of a polymerization solvent. These catalyst components may be added all at once or sequentially. As the order of addition, it is preferable to add 1,3-butadiene, a cobalt compound, an organoaluminum compound, an organoaluminumoxy compound, carbon disulfide and the like in this order.

The polymerization temperature is preferably in the range of 0 to 100 ° C,
The range of 10 to 50 ° C is particularly preferable. The polymerization time is preferably in the range of 10 minutes to 12 hours, particularly preferably 30 minutes to 6 hours.

As the polymerization solvent, toluene, benzene,
Aromatic hydrocarbons such as xylene, n-hexane, butane,
Aliphatic hydrocarbons such as heptane, pentane, 1-butene, 2-
Examples include olefinic hydrocarbons such as butene, mineral spirits, solvent naphtha, kerosene and other hydrocarbon solvents, and methylene chloride and other halogenated hydrocarbon solvents. Further, 1,3-butadiene itself may be used as the polymerization solvent.

As the monomer, those containing 1,3-butadiene as a main component can be used. In addition to 1,3-butadiene, conjugated dienes such as isoprene, chloroprene and myrcene, ethylene, propylene and butene- 1, butene-2,
It may contain olefins such as isobutene and pentene-1, and / or aromatic vinyl compounds such as styrene and α-methylstyrene.

After the polymerization is carried out for a predetermined time, the pressure inside the polymerization tank is released if necessary, and post-treatments such as washing and drying steps are carried out.

The structure of polybutadiene can be determined by infrared absorption method such as Morero method, ¹ H-NMR, ¹³ C-NMR and the like.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION 【Example】

(Measurement method) The melting point (Tm) of polybutadiene was determined from the DSC chart, and the temperature corresponding to the endothermic peak was taken as the melting point.

DSC is SSC manufactured by Seiko Electronics Co., Ltd.
5200 was used, and the measurement was performed under a nitrogen atmosphere under the conditions of a sample amount of 10 mg and a heating rate of 10 ° C./min.

Example 1 The inside of an autoclave having an internal capacity of 2 L was replaced with nitrogen, and 600 mL of toluene and 62 g of 1,3-butadiene were charged. Next, add a solution of cobalt octenoate (CoOct) in toluene (concentration: cobalt octenoate 0.5 mmoL / toluene 1 mL).
0.2mL, toluene solution of triethyl aluminum (AlEt ₃ ) (concentration: triethyl aluminum 1mmoL / toluene
0.3 mL of 1 mL) and stirred at room temperature for 10 minutes, and then
0.95 mL of a toluene solution of methylalumoxane (concentration: 2.11 mmoL of methylalumoxane / 1 mL of toluene) and a toluene solution of carbon disulfide (concentration: 0.83 mmoL of carbon disulfide /
Toluene 1mL) 0.48mL was added sequentially, and the polymerization temperature was 30 ℃.
Polymerization was carried out for 45 minutes.

After the polymerization, 10 mL of methanol was added to stop the polymerization. Then, unreacted 1,3-butadiene was discharged from the autoclave, and 300 mL of methanol was added to precipitate a polymer. Furthermore, this polymer was put into 700 mL and washed. The washed polymer was washed twice with methanol containing an antioxidant and then vacuum dried. The ratio of SPB and cis polybutadiene in the produced polymer was determined by the following method. 3 g of the finely cut polymer was added to 400 mL of toluene, and the mixture was stirred at room temperature for 16 hours. Then, the extract was filtered through a glass filter (G-4) and washed with toluene to separate into a toluene insoluble portion and a soluble portion. Insoluble part remains at 60 ℃
It was dried under reduced pressure for 5 hours. In addition, after the soluble portion was distilled off, 60
It was dried under reduced pressure at 5 ° C for 5 hours. After drying, it was allowed to cool and weighed to determine the weight% of each. Table 1, Table 2 and Table 3 collectively show the polymerization conditions and the polymerization results.

Examples 2 to 11 Polymerization was carried out in the same manner as in Example 1 under the conditions shown in Tables 1 and 2. The results are shown in Table 3.

Comparative Examples 1-2 Under the conditions shown in Table 1 and Table 2, polymerization was carried out in the same manner as in Example 1. The results are shown in Table 3.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

EFFECTS OF THE INVENTION The present invention provides a method for producing highly crystalline 1,2-polybutadiene or a mixture of highly crystalline 1,2-polybutadiene and cis polybutadiene with high productivity. You can

Claims (1)

[Claims] 1. A compound selected from the group consisting of (A) a cobalt compound, (B) carbon disulfide, phenyl isothiocyanate and a xanthogenic acid compound, and (C) a general formula Al.
R ₃ (In the formula, R is a hydrocarbon group having 1 to 10 carbon atoms.)
Using a catalyst composed of an organoaluminum compound represented by and (D) an organoaluminum oxy compound,
A method for producing polybutadiene, which comprises polymerizing 3-butadiene.