JPH1036418A - Preparation of polybutadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain polybutadiene which has a high cis-1,4-content, a low gel content and a high linearity by polymerizing 1,3-butadiene by using a catalyst prepared from a Co compound, alumoxane and organic halogen compound. SOLUTION: 1,3-Butadiene is polymerized by using a catalyst prepared from (A) a Co compound (preferably a salt or complex of cobalt), (B) almoxane (a chain or cyclic aluminooxane prepared by bringing an organic Al compound into contact with a condensation agent), and (C) an organic halogen compound [e.g. an alkyl halide of formula RX (wherein R is a 1-20C hydrocarbon group; and X is a halogen)]. The polybutadiene thus formed has a high cis-1,4-content and a low gel content.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high cis-1,4-polybutadiene having a low gel content by polymerizing 1,3-butadiene.

[0002]

2. Description of the Related Art For polymerization catalysts for 1,3-butadiene,
Many proposals have been made before, especially high cis-1,4
-Many polymerization catalysts have been developed because polybutadiene, that is, polybutadiene having a high cis-1,4 bond content, has excellent thermal and mechanical properties.

[0003] For example, in Canadian Patent No. 795860,
Mix the hydrocarbyl aluminum compound and water well,
A process is disclosed for producing high cis-1,4-polybutadiene by polymerizing an aged mixture of cobalt dioctoate and 1,3-butadiene in a solvent containing at least 20% benzene.

Japanese Patent Publication No. Sho 61-54808 discloses that 1,3-butadiene is dissolved in a solvent comprising a linear or branched aliphatic hydrocarbon using a catalyst comprising diethylaluminum chloride, water and cobalt octoate. A method of polymerizing is disclosed. Japanese Patent Application Laid-Open No. Hei 7-188341 discloses that a catalyst composed of a divalent cobalt salt, an alkylaluminum chloride, and two kinds of trialkylaluminum is used in a medium consisting of a solvent containing no aromatic compound and water. 3-
A method for polymerizing butadiene is disclosed.

[0005] Polym. Commun., Vol. 32, 514 (1991) discloses a method for polymerizing 1,3-butadiene using a catalyst comprising cobalt acetylacetonate and methylalumoxane. However, in the polymerization of 1,3-butadiene, the resulting polymer contains a double bond, so that gels are likely to be formed especially when no aromatic solvent is contained, or when the polymerization activity is low depending on the catalyst system. Yes, improvements are desired.

Further, high cis-1,4-polybutadiene having a small degree of branching of the polymer chain has excellent properties such as abrasion resistance, heat resistance, and rebound resilience. However, high cis synthesized in a solvent system that does not contain aromatic compounds
The degree of branching of -1,4-polybutadiene was larger than that of a solvent system containing an aromatic compound. Therefore, there is a need for a method of producing a high cis-1,4-polybutadiene having a small degree of branching in a solvent system containing no aromatic compound.

As an index of the degree of branching of high cis-1,4-polybutadiene, toluene solution viscosity (T _cp ) and Mooney viscosity (M
L _{1 + 4} ) (T _CP / ML _{1 + 4} ). T _CP indicates the degree of entanglement of molecules in a concentrated solution, and for high cis-1,4-polybutadiene having a similar molecular weight distribution, the same molecular weight (ie, ML _{1+ 4} as long as any) is greater the degree of branching index (T _cp identical degree of branching is made smaller). T _CP / ML _{1 + 4} is ML
_When comparing the degree of branching of _{1 + 4} different high cis-1,4-polybutadiene, it is used as an index (the larger the _TCP / ML _{1 + 4} , the smaller the degree of branching).

[0008]

SUMMARY OF THE INVENTION The present invention provides a high cis-
An object of the present invention is to provide a method for producing polybutadiene having a 1,4 content, a low gel content, and a high linearity.

[0009]

The present invention is characterized in that 1,3-butadiene is polymerized using a catalyst obtained from (A) a cobalt compound, (B) an alumoxane, and (C) an organic halogen compound. To a method for producing polybutadiene. The present invention also relates to a method for producing polybutadiene, which comprises polymerizing 1,3-butadiene using a catalyst comprising (A) a cobalt compound, (B) an alumoxane, and (C) an organic halogen compound.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As the cobalt compound (A) in the present invention, a salt or complex of cobalt is preferably used. Particularly preferred are cobalt salts such as cobalt chloride, cobalt bromide, cobalt nitrate, cobalt octylate, cobalt naphthenate, cobalt acetate, and cobalt malonate, and bisacetylacetonate, trisacetylacetonate, and ethyl acetoacetate of cobalt. Examples thereof include triarylphosphine complexes and trialkylphosphine complexes of ester cobalt and cobalt halide, organic base complexes such as pyridine complexes and picoline complexes, and ethyl alcohol complexes.

The alumoxane of the component (B) is obtained by contacting an organoaluminum compound with a condensing agent, and has the general formula (-Al (R ') O
-) A chain aluminoxane represented by _n or a cyclic aluminoxane is exemplified. (R ′ is a hydrocarbon group having 1 to 10 carbon atoms, including those partially substituted with a halogen atom and / or an alkoxy group. As R ′, methyl,
Examples include ethyl, propyl, and isobutyl groups. Examples of the organoaluminum compound used as a raw material of the aluminoxane include trialkylaluminums such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, and mixtures thereof.

Alumoxane using a mixture of trimethylaluminum and tributylaluminum as a raw material can be suitably used.

Examples of the condensing agent include water as a typical one, and any other condensing agent capable of condensing the trialkylaluminum, for example, adsorbed water such as inorganic substances and diol.

The organic halogen compound as the component (C) is represented by the general formula RX (where R is a hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 20 carbon atoms, and X is a halogen). And alkyl halide compounds. Examples of the hydrocarbon group include an alkyl group, an aryl group, and a cycloalkyl group.

An organic halogen compound represented by the general formula R ¹ R ² R ³ C—X can be used. Where:
R ¹ represents hydrogen, an alkyl group, an aryl group, chloro substituted alkyl group, and the like alkoxy groups, R ² represents hydrogen, an alkyl group, an aryl group, chloro, bromo and the like, R ² +
R ³ may be oxygen, R ³ is an alkyl group, an aryl group, a vinyl group, chloro, bromo and the like, and X is a halogen such as chloro and bromo. When R ¹ and R ² are hydrogen, R ³ is preferably an aryl group. The alkyl group may be saturated or unsaturated, and may be linear, branched or cyclic. And aliphatic hydrocarbon groups.

Specific compounds include methyl, ethyl,
Chloride or bromide such as iso-propyl, iso-butyl, t-butyl, phenyl, benzyl, benzoyl, benzylidene and the like can be mentioned. Further, methyl chloroformate, bromoformate, chlorodiphenylmethane, chlorotriphenylmethane and the like can be mentioned.

In the present invention, the component (A)
In addition to the component (B) and the component (C), a trialkylaluminum compound may be further added as the component (D). Specific examples of the trialkylaluminum compound include triethylaluminum, trimethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, and the like.

The amount of the cobalt compound (A) used is as follows:
Usually 1 × of cobalt compound is added to 1 mol of butadiene.
It is preferred that the amount be in the range of 10 ^-7 to 1 × 10 ^-4 mol, preferably 1 × 10 ^-6 to 1 × 10 ^-5 mol.

The amount of the alumoxane used as the component (B) is usually in the range of 10 to 5000 mol, preferably 50 to 1000 mol, per 1 mol of the cobalt compound.

The amount of the halogenated alkyl compound used as the component (C) depends on the amount of the halogen atom (X) in the organic halogen compound.
And the ratio of the aluminum atoms (Al) in the alumoxane (X
/ Al) is 0.02 ≦ X / Al ≦ 1.33, preferably 0.1 ≦ X /
It is preferable that Al ≦ 0.80.

When the trialkylaluminum compound (D) is used, the ratio (X / Al) of the halogen atom (X) in the organic halogen compound to the aluminum atom (Al) in the trialkylaluminum compound and alumoxane is used.
But 0.02 ≦ X / Al ≦ 2.0, preferably 0.1 ≦ X / Al ≦ 1.
It is preferably in the range of 33.

The order of addition of the catalyst components is not particularly limited.
It is preferable to add the components (B), (C), and (A) in this order. The component (B) and the component (C) or the component (D) may be aged in advance in an inert solvent before use. The aging time is preferably 0.1 to 10 hours. The aging temperature is preferably from 0 to 80 ° C.

The polymerization method is not particularly limited.
Solution polymerization or the like can be applied. Examples of the solvent in the solution polymerization include aromatic hydrocarbons such as toluene, benzene, and xylene; aliphatic hydrocarbons such as n-hexane, butane, heptane, and pentane; cycloaliphatic hydrocarbons such as cyclopentane and cyclohexane; -Butene, cis-2-butene, trans-2-
Examples thereof include hydrocarbon solvents such as olefin hydrocarbons such as butene, mineral spirit, solvent naphtha, and kerosene, and halogenated hydrocarbon solvents such as methylene chloride. Further, 1,3-butadiene itself may be used as the polymerization solvent.

Among them, cyclohexane or cis
A mixture of -2-butene and trans-2-butene is preferably used.

In the present invention, a known molecular weight regulator at the time of polymerization, for example, non-conjugated dienes such as cyclooctadiene and arene, or ethylene, propylene, butene-1
Α-olefins can be used.

The polymerization temperature is preferably in the range of -30 to 100 ° C, particularly preferably in the range of 30 to 80 ° C. Polymerization time is 10 minutes ~
A range of 12 hours is preferred, with 30 minutes to 6 hours being particularly preferred. The polymerization is carried out under normal pressure or under pressure up to about 10 atm (gauge pressure).

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

[0028]

EXAMPLES Microstructure was performed by infrared absorption spectroscopy. Cis 740 cm ^-1 , transformer 967 cm ^-1 , 1,
The microstructure was calculated from the absorption intensity ratio of 2-910 cm ^-1 .
The molecular weight distribution was determined using GP using polystyrene as a standard.
Ratio of weight average molecular weight Mw and number average molecular weight Mn obtained from C
Evaluated by Mw / Mn.

The Mooney viscosity (ML _{1 + 4} ) is JIS K6300
It measured according to. Toluene solution viscosity (T _cp ) was determined by dissolving 2.28 g of polymer in 50 ml of toluene, using a standard solution for viscometer calibration (JIS Z8809) as a standard solution, and using a Cannon-Fenske viscometer No. 400 as a standard solution. Measured in ° C. The gel content was determined by dissolving about 5 g of the polymer in 200 mL of toluene, filtering this through a 250-mesh wire gauze, washing the wire gauze thoroughly with toluene, and increasing the weight of the wire gauze after vacuum drying at 80 ° C for 5 hours. Calculated.

Example 1 The inside of a flask having an internal volume of 50 mL was replaced with nitrogen, and 31.7 mL of cyclohexane was charged. Then, 2.00 mL of a toluene solution of 3.46 mmol (in terms of aluminum atom) of methylalumoxane (MAO) as the component (B) and 0.865 mL of a cyclohexane solution of 0.865 mmol of t-butyl chloride (t-BuCl) as the component (C) are added. And aged at room temperature for 30 minutes.

The inside of a 1.5 L autoclave was replaced with nitrogen, and 500 mL of cyclohexane and 1,3-butadiene 1
55g was charged. A cyclohexane solution of 9.0 mmol of 1,5-cyclooctadiene (COD) as a molecular weight regulator, 24 mL of the above ripening solution, and a 0.006 mmol solution of cobalt octenoate (Co (Oct) ₂ ) in cyclohexane as the component (A) were added, followed by polymerization. Polymerization was performed at a temperature of 65 ° C. for 30 minutes. Tables 1 and 2 show the polymerization and aging conditions, and Tables 3 and 4 show the polymerization results and the analysis results of the obtained polybutadiene.

Examples 2 and 3 The same procedure as in Example 1 was carried out except that the addition amount of the component (C) was changed. Tables 1 and 2 show the polymerization and aging conditions, and Tables 3 and 4 show the polymerization results and the analysis results of the obtained polybutadiene.

Examples 4 and 5 MAO as component (B) and t-BuC as component (C)
l, and triethylaluminum (T
EA) was carried out in the same manner as in Example 1 except for aging. The polymerization conditions are shown in Tables 1 and 2, and the results of the polymerization and the results of analysis of the obtained polybutadiene are shown in Tables 3 and 4.

Comparative Example 1 The same procedure as in Example 1 was carried out except that COD and t-BuCl were not added. The polymerization conditions are shown in Tables 1 and 2, and the results of the polymerization and the results of analysis of the obtained polybutadiene are shown in Tables 3 and 4.

Comparative Example 2 The inside of an autoclave having a content of 1.5 L was replaced with nitrogen, and 500 mL of cyclohexane and 155 g of 1,3-butadiene were charged. Next, a cyclohexane solution of 1.2 mmol of water (H ₂ O) and 9.0 mmol of 1,5-cyclooctadiene (COD) as a molecular weight regulator was added, and the mixture was stirred for 30 minutes. Then, diethyl aluminum chloride (DEAC) in cyclohexane 2.4mmol solution, Co and (Oct) ₂ 0.006 mmol of cyclohexane solution was added, for 30 minutes polymerization was carried out at a polymerization temperature of 65 ° C.. The polymerization conditions are shown in Tables 1 and 2, and the results of the polymerization and the results of analysis of the obtained polybutadiene are shown in Tables 3 and 4.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

[Table 3]

[0039]

[Table 4]

[0040]

The present invention provides a process for producing polybutadiene having a high cis-1,4 content, a low gel content and a high linearity.

Claims (2)

[Claims] 1. A method for producing polybutadiene, comprising polymerizing 1,3-butadiene using a catalyst obtained from (A) a cobalt compound, (B) an alumoxane, and (C) an organic halogen compound. 2. A method for producing polybutadiene, comprising polymerizing 1,3-butadiene using a catalyst comprising (A) a cobalt compound, (B) an alumoxane, and (C) an organic halogen compound.