JPH11209433A - Polybutadiene and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a low-molecular-weight polybutadiene having a microstructure containing a high cis structure with an appropriate amount of 1,2-structure and a lesser amount of trans structure by making the polybutadiene comprising the 1,2-structure unit, cis-1,4-structure unit and trans-1,4-structure unit each having a specific content and by specifying its intrinsic viscosity. SOLUTION: Each content is 20-40 mol.% for a 1,2-structure unit, 50-70 mol.% for a cis-1,4-structure unit and 6-20 mol.% for a trans-1,4-structure unit. An intrinsic viscosity (30 deg.C, toluene) is 0.01-0.5. A polybutadiene is prepared by polymerizing 1,3-butadiene in the presence of a catalyst obtained from a Co component (e.g.: cobalt chloride), an organic Al compound (e.g.: halogen- containing aluminum compound) and water, wherein a molar ratio of the organic Al compound to water is 2 or higher and a molar ratio of the organic Al compound to the Co compound is 100 or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a low molecular weight polybutadiene having a controlled microstructure and a method for producing the same.

[0002]

2. Description of the Related Art Low molecular weight polybutadiene is used in various applications such as paints, plasticizers and adhesives, for example, as a modifier for general rubbers and as a binder for paints as an additive. Polybutadiene has a so-called microstructure,
The bonding portion (1,4-structure) formed by polymerization at 1,4-position and the bonding portion (1,2 structure) formed by polymerization at 1,2-position
-Structure) coexist in the molecular chain. The 1,4-structure is further divided into two types, a cis structure and a trans structure. on the other hand,
The 1,2-structure takes a structure having a vinyl group as a side chain.

[0003] It is known that polybutadienes having different microstructures are produced by a polymerization catalyst, and are used for various purposes depending on their properties.

[0004] In particular, low molecular weight polybutadiene having a microstructure including a 1,2-structure and a trans structure in a moderately high cis structure is expected as an additive having a good balance of physical properties.

As a low molecular weight polybutadiene having a specific microstructure, for example, Japanese Patent Publication No. Sho 42-9017 discloses a polybutadiene produced using a catalyst system comprising a cobalt compound and an organoaluminum compound.
The content of 1,2-structural units is 6.4%, and cis-1,
4- The content of structural units is 89.1%, trans-
Polybutadiene having a 1,4-structural unit content of 4.5% and an intrinsic viscosity of 0.6 is described.

Japanese Patent Publication No. 52-32912 discloses a polybutadiene produced using a catalyst system consisting of a cobalt compound, a halogen-containing organoaluminum compound and an organophosphorus compound. Low molecular weight polybutadienes with a high content are described.

Japanese Patent Publication No. 57-15604 discloses a polybutadiene produced by using a catalyst system comprising a cobalt compound, a trialkylaluminum compound and hexachloroethane, which contains 1,2-structural units. Is low molecular weight polybutadiene having a cis-1,4-structural unit content of 35 to 85 mol% and a trans-1,4-structural unit content of 20 mol% or less. I have.

[0008] However, in the high cis structure,
A low molecular weight polybutadiene having a microstructure including a 2-structure and a trans structure is not known, and the above-mentioned polymerization catalysts in the prior art have problems such as low activity, low productivity, and a wide molecular weight distribution. There is.

[0009]

DISCLOSURE OF THE INVENTION The present invention relates to a low molecular weight polybutadiene having a microstructure including a 1,2-structure and a trans structure moderately in a high cis structure, and having a narrow molecular weight distribution, and a polymer having a high polymerization activity. It is an object of the present invention to provide a method which can be manufactured by the method.

[0010]

According to the present invention, there are provided (1) a butadiene monomer unit having a 1,2-structural unit content of 20 to 40 mol% and a cis-1,4-structural unit content of: 50-70 mol%, and trans-1,4-
The content of the structural unit is 6 to 20 mol%, and (2) the intrinsic viscosity [η] measured in toluene at 30 ° C.
Is from 0.01 to 0.5.

The present invention also relates to a catalyst obtained from a cobalt compound, an organoaluminum compound and water, wherein the molar ratio of the organoaluminum compound to water is 2 or more;
When the molar ratio between the organoaluminum compound and the cobalt compound is 1
The present invention relates to the above method for producing polybutadiene, wherein 1,3-butadiene is polymerized in the presence of a catalyst having a molecular weight of not more than 00.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polybutadiene of the present invention comprises 1,
The content of the 2-structural unit is 20 to 40 mol%, preferably 25 to 35 mol%, more preferably 27 to 34 mol%, and the content of the cis-1,4-structural unit is 50 to 70.
Mol%, preferably 50-65 mol%, and trans-
The content of the 1,4-structural unit is 6 to 20 mol%, preferably 7 to 16 mol%.

If the microstructure is out of the above range, the reactivity of the polymer (such as graft reaction and cross-linking reactivity) is not appropriate, and the rubber-like properties when used as an additive or the like are reduced, and the physical properties are reduced. It unfavorably affects the balance and appearance.

The polybutadiene of the present invention has an intrinsic viscosity [η] measured at 30 ° C. in toluene of 0.01 to 0.01.
0.5, preferably 0.05 to 0.3.

The molecular weight of the polybutadiene of the present invention is preferably in the following range as the molecular weight in terms of polystyrene.

Number average molecular weight (Mn): 0.05 × 10 ⁴
4 × 10 ⁴ , more preferably 0.1 × 10 ^{4 to} 3 × 1
0 ⁴

Weight average molecular weight (Mw): 0.1 × 10 ⁴
７7 × 10 ⁴ , more preferably 0.2 × 10 ⁴ -6 × 1
0 ⁴

The polybutadiene of the present invention preferably has a molecular weight distribution (Mn / Mw) of 1.5 to 3.5,
More preferably, it is 2.0 to 2.5.

The method for producing polybutadiene according to the present invention includes, for example, a catalyst obtained from a cobalt compound, an organoaluminum compound and water, wherein the molar ratio of the organoaluminum compound to water is 2 or more, and It can be produced by polymerizing 1,3-butadiene in the presence of a catalyst having a cobalt compound molar ratio of 100 or less.

As the cobalt compound, 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 and trisacetylacetonate of cobalt. And organic base complexes such as triarylphosphine complexes, trialkylphosphine complexes, pyridine complexes and picoline complexes of cobalt acetoacetate, cobalt halides, and ethyl alcohol complexes.

Of these, cobalt octylate, cobalt naphthenate, cobalt bisacetylacetonate and trisacetylacetonate are preferred.

Examples of the organic aluminum compound include a halogen-containing aluminum compound and a trialkylaluminum compound.

As the halogen-containing aluminum compound,
Examples thereof include dialkylaluminum halides such as dialkylaluminum chloride and dialkylaluminum bromide, alkylaluminum sesquichlorides such as alkylaluminum sesquibromide, and alkylaluminum dihalides such as alkylaluminum dichloride and alkylaluminum dibromide.

Specific examples of the compound include diethylaluminum monochloride, diethylaluminum monobromide, dibutylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, dicyclohexylaluminum monochloride, diphenylaluminum monochloride, triethylaluminum, trimethylaluminum, trimethylaluminum Isobutylaluminum, trihexylaluminum, trioctylaluminum and the like.

Of the above compounds, diethyl aluminum monochloride, diethyl aluminum monobromide, ethyl aluminum sesquichloride and ethyl aluminum dichloride are preferred.

The molar ratio of the organoaluminum compound to water is
It is 2 or more, preferably 3 or more, and preferably 100 or less as an upper limit. The molar ratio of the organoaluminum compound to the cobalt compound is 100 or less, preferably 50 or less, and the lower limit is preferably 1 or more.

The order of addition of the catalyst component is not particularly limited, but for example, it can be performed in the following order. Water is added to the monomer to be polymerized or a mixture of the monomer and the solvent, and then the organic aluminum compound and the cobalt compound are added in this order. Water and the organoaluminum compound are added in any order to add the cobalt compound. The organoaluminum compound and the cobalt compound are mixed in the presence of water.

The polymerization method is not particularly limited, and includes solution polymerization,
Bulk polymerization using 1,3-butadiene itself as a polymerization solvent 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; alicyclic hydrocarbons such as cyclopentane and cyclohexane; Olefinic hydrocarbons such as -butene, cis-2-butene and trans-2-butene, mineral spirits,
Examples include hydrocarbon solvents such as solvent naphtha and kerosene, and halogenated hydrocarbon solvents such as methylene chloride.

In addition to butadiene monomer, isoprene,
Conjugated dienes such as 1,3-pentadiene, 2-ethyl-1,3-butadiene, 2,3-dimethylbutadiene, 2-methylpentadiene, 4-methylpentadiene, 2,4-hexadiene, ethylene, propylene, butene-
1, non-cyclic monoolefins such as butene-2, isobutene, pentene-1,4-methylpentene-1, hexene-1 and octene-1, cyclic monoolefins such as cyclopentene, cyclohexene and norbornene, and / or styrene or α A small amount of an aromatic vinyl compound such as -methylstyrene, a non-conjugated diolefin such as dicyclopentadiene, 5-ethylidene-2-norbornene, and 1,5-hexadiene may be contained.

The polymerization temperature is preferably in the range of -100 to 200 ° C, particularly preferably in the range of -50 to 120 ° C. The polymerization time is preferably in the range of 2 minutes to 12 hours, particularly preferably in the range of 5 minutes to 6 hours.

After the polymerization is carried out for a predetermined time, the polymerization is stopped by injecting a terminating agent such as an alcohol, and then the pressure inside the polymerization tank is released as required, and post-treatments such as washing and drying steps are performed.

[0032]

EXAMPLES Microstructure was performed by infrared absorption spectroscopy. The microstructure was calculated from the absorption intensity ratio of cis 740 cm ^-1 , trans 967 cm ^-1 , and vinyl 910 cm ^-1 . The molecular weight distribution was evaluated by the ratio Mn / Mw of the weight average molecular weight Mw and the number average molecular weight Mn obtained from GPC using polystyrene as a standard substance.

[Η] was measured in a toluene solution at a temperature of 30 ° C.

Example 1 The interior of an autoclave having a content of 1.5 L was replaced with nitrogen, and 30% by weight of 1,3-butadiene, 25% by weight of benzene and 45% by weight of 2-butene were obtained.
1 L of a solution (201 g of butadiene) mixed with wt% was charged, and 0.95 mmol of water (H ₂ O) was added at room temperature, followed by vigorous stirring at 700 rpm for 30 minutes. 5.7 mL of a cyclohexane solution (1 mol / L) of diethylaluminum chloride (DEAC) was added, and the mixture was stirred at room temperature for 5 minutes. Heated to 65 ° C., cobalt octoate (Co (Oc
t) 1 mL of a toluene solution (0.2 mol / L) of ₂ )
Was added to start polymerization, and polymerization was performed at 70 ° C. for 30 minutes.
After completion of the polymerization, 5 mL of an ethanol / heptane (1/1) solution containing an antioxidant was added to terminate the polymerization. After releasing the pressure inside the autoclave, unreacted butadiene and the solvent were removed and dried to recover polybutadiene. Table 2
And Table 3 show the results.

(Examples 2 to 8) Operations were performed in the same manner as in Example 1 except that the conditions were as shown in Table 1. Tables 2 and 3 show the results.

Examples 9 to 11 The same procedures as in Example 5 were carried out except that a mixed solution of butadiene and a solvent shown in Table 4 was used. Tables 2 and 3 show the results.

Comparative Example 1 The procedure of Example 1 was repeated except that the polymerization conditions and the polymerization time shown in Table 1 were changed to 3 minutes.
Tables 2 and 3 show the results.

Comparative Example 2 Other than the polymerization conditions shown in Table 1,
Performed in the same manner as in Example 1. Tables 2 and 3 show the results.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

The present invention provides a low-molecular-weight polybutadiene having a microstructure containing a 1,2-structure in a moderately high cis structure and a small trans structure, and a method for producing the same.

Claims (2)

[Claims] (1) Among butadiene monomer units, the content of 1,2-structural units is 20 to 40 mol%, and the content of cis-1,4-structural units is 50 to 70.
Mol% and the content of the trans-1,4-structural unit is 6 to 20 mol%, and (2) the intrinsic viscosity [η] measured at 30 ° C. in toluene is 0.01 to 0.5 mol%. A polybutadiene, which is 2. A catalyst obtained from a cobalt compound, an organoaluminum compound and water, wherein the molar ratio of the organoaluminum compound to water is 2 or more, and the molar ratio of the organoaluminum compound and the cobalt compound is 100 or less. The method for producing polybutadiene according to claim 1, wherein 1,3-butadiene is polymerized in the presence of a catalyst.