JPH05194657A - Production of butadiene-based polymer - Google Patents

Abstract

PURPOSE:To produce the subject butadiene-based polymer capable of widely using a polymerization solvent and providing a polymer having a high melting point and a narrow molecular weight distribution and further a high content of 1,2-bonds. CONSTITUTION:A conjugated diene containing at least >=50mol% 1,3-butadiene is polymerized in an inert organic solvent by using a catalyst containing (A) a cobalt compound, (B) an aluminoxane, (C) a trialkylaluminum and (D) water at 0.1-10 atomic ratio of aluminum in the components [(B)/(C)] and 0.1-1.8 molar ratio of the components [(D)/(C)].

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a butadiene-based polymer, and more specifically, it uses a polymerization catalyst that is highly active even in a wide range of polymerization solvent systems, has a high melting point, a narrow molecular weight distribution, and a high molecular weight distribution. The present invention relates to a method for producing a butadiene-based polymer having a 2-bond content.

[0002]

2. Description of the Related Art The structure of a butadiene-based polymer containing 1,3 butadiene as a main component is greatly influenced by the catalyst system. For example, it is known that cis or trans 1,4-polybutadiene can be obtained with a catalyst system composed of a transition metal compound and alkylaluminum. In addition, CoBr
It is known that syndiotactic 1,2-polybutadiene can be obtained from a catalyst system consisting of ₂ (PPh ₃ ) ₂ , trialkylaluminum and water [Y. Ob
ata et al., Polym. J. , 7 , 207 (197
5), JP-B-44-32425].

On the other hand, BuLi or Cr (aca
from the catalyst system consisting of _{c) 3 -Al (C 2 H} 5) 3, are each known to atactic and isotactic 1,2-polybutadiene is obtained [A. F. H
alasa et al. Polym. Sci. Polym.
Chem. Ed. , 19 , 1357 (1981);
Natta et al., Chem. Ind. (Millan),
41 , 1163 (1959)]. However, these catalyst systems have high polymerization activity in halogenated hydrocarbon solvents such as methylene chloride, which may cause environmental problems, but have low polymerization activity in hydrocarbon solvents and should be applied to a wide range of polymerization solvent systems. In addition, a polymer having a high melting point and a narrow molecular weight distribution cannot be obtained, and a butadiene-based polymer having a high 1,2-bond content cannot be obtained.

[0004]

The present invention has been made against the background of the above-mentioned problems of the prior art. It is possible to use a wide range of polymerization solvents by using a specific catalyst, and the obtained polymer is also high. An object of the present invention is to provide a method for producing a butadiene-based polymer having a narrow melting point and a narrow molecular weight distribution and a high 1,2-bond content.

[0005]

The present invention provides a conjugated diene containing at least 50 mol% of 1,3-butadiene, (A) a cobalt compound, (B) an aluminoxane,
It contains (C) trialkylaluminum and (D) water, and has a (B) / (C) (aluminum atomic ratio) of 0.
1 to 10, (D) / (C) (molar ratio) is 0.1 to 1.8
The present invention provides a method for producing a butadiene-based polymer, which comprises polymerizing in an inert organic solvent using the above catalyst.

As the conjugated diene other than 1,3-butadiene used in the present invention, 1,3-pentadiene, 1,3-butadiene derivative substituted with a higher alkyl group, 2
-Alkyl-substituted-1,3-butadiene and the like. Among these, 1,3-butadiene derivatives substituted with higher alkyl groups include 1-pentyl-1,3-butadiene, 1-hexyl-1,3-butadiene, 1-heptyl-1,3-butadiene, and 1-pentyl-1,3-butadiene. -Octyl 1,3-butadiene and the like.

Typical examples of 2-alkyl-substituted-1,3-butadiene include 2-methyl-1,3-butadiene (isoprene), 2-ethyl-1,3-butadiene,
2-propyl-1,3-butadiene, 2-isopropyl-1,3-butadiene, 2-butyl-1,3-butadiene, 2-isobutyl-1,3-butadiene, 2-amyl-1,3-butadiene, 2-isoamyl-1,3-butadiene, 2-hexyl-1,3-butadiene, 2-cyclohexyl-1,3-butadiene, 2-isohexyl-
1,3-butadiene, 2-heptyl-1,3-butadiene, 2-isoheptyl-1,3-butadiene, 2-octyl-1,3-butadiene, 2-isooctyl-1,3
-Butadiene and the like. Among these conjugated dienes, preferred conjugated dienes to be used by mixing with 1,3-butadiene include isoprene and 1,3-pentadiene. The content of 1,3-butadiene in the monomer component to be polymerized is 50 mol% or more, preferably 70 mol% or more, and when it is less than 50 mol%, the vinyl bond content in the butadiene-based polymer is controlled. Is difficult and not preferable.

Next, as the cobalt compound (A) used in the catalyst of the present invention, compounds having an apparent zero valence to the highest valence are used. For example, as the cobalt compound (A), an inorganic acid salt, an organic acid salt,
It is a complex consisting of these salts and an electron donor, a zero-valent complex or a divalent complex having only an organic ligand, and typical examples thereof include halides, sulfates, nitrates,
Carbonates, phosphates, sulfides, hydroxides, cyanides, thiocyanates, naphthenates, octenoates, etc., as electron donors for complex formation, phosphine compounds, phosphite compounds, pyridine, As a zero-valent complex such as amine, alcohol, water, dipyridyl, and phenanthroline, carbonyl, isonitrile, phosphine compound, phosphite compound, dipyridyl, unsaturated hydrocarbon, vinyl compound, cyclopentadienyl, π-is used as a ligand. Having at least one of allyl and its derivatives,
The divalent complex has acetylacetone, acetoacetic acid or the like as a ligand.

Of these, preferred (A) cobalt compounds are complexes having an organic phosphine compound as a ligand, such as cobalt bis (triphenylphosphine) dibromide and cobalt bis (triphenylphosphine).
Dichloride, cobalt bis (tri-m-methylphenylphosphine) dibromide, cobalt bis (tri-m
Examples include cobalt phosphine compounds such as -methylphenylphosphine) dichloride and cobalt bis (tri-m-dimethylphenylphosphine) dibromide.

Among the catalysts of the present invention, examples of the (B) aluminoxane include those represented by the general formula (I) or the general formula (II).

[0011]

[Chemical 1]

[0012]

[Chemical 2]

An organoaluminum compound represented by the formula (wherein R represents a hydrocarbon group and m represents an integer of 2 or more) can be mentioned. In the (B) aluminoxane represented by the general formula (I) or (II), R is a methyl group,
Hydrocarbon groups such as ethyl group, propyl group and butyl group are preferable, methyl group and ethyl group are preferable, and methyl group is particularly preferable. Further, m is an integer of 2 or more, preferably 5 or more, more preferably 10 to 100.
Specific examples of (B) aluminoxane include methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, and the like.

Further, among the catalysts of the present invention, examples of the (C) trialkylaluminum include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, etc. Among them, triisobutylaluminum is highly active for polymerization. It is preferable because the optimum catalyst composition range is wide.

The amount of the component (C) used is (B) / (amount of aluminum atom) of the component (B) and the component (C).
(C) = 0.1 to 10 is preferable because it has the effect of increasing the melting point and molecular weight of the obtained butadiene-based polymer and further narrowing the molecular weight distribution. When (B) / (C) is less than 0.1, the polymerization activity is remarkably reduced, while when it exceeds 10, the polymerization activity is increased, but the melting point and molecular weight of the obtained butadiene-based polymer are lowered, and the molecular weight distribution is low. It is not preferable because a wide range of products can be obtained.

Further, in the catalyst of the present invention, as the water (D), any water may be used, but single water such as ion-exchanged water or distilled water, or water contained in crystal water is used. it can. Of these, the addition of water alone is preferable from the viewpoint of reactivity with the organoaluminum component. The amount of water (D) used was 0.1% per mole of (C) trialkylaluminum.
It is 1 to 1.8 moles, preferably 0.3 to 1.5 moles, and if it is less than 0.1 moles or exceeds 1.8 moles, the polymerization activity remarkably decreases, which is not preferable.

The amount of the other catalyst used in the present invention is such that the cobalt compound (A) is 5 × 10 ² to 10 ⁵ , preferably 10 ³ to 10 in terms of the ratio of the molar amount of butadiene to the cobalt atom. is ^6, 5 × 10 high catalyst concentration is less than ^2, catalyst removal step is required, whereas not preferred in view of polymerization activity of the catalyst exceeds 10 ^5. Also,
The amount of the (B) aluminoxane and the (C) trialkylaluminum used is usually 4 to 10 as the ratio of the aluminum atoms obtained by summing the (B) to (C) components with respect to the cobalt atoms of the (A) cobalt compound. ⁶ , preferably 10 to 10 ^{5 in} terms of practical polymerization activity and control of molecular weight
Preferably, low catalytic activity is less than 10, but preferably from polymerization activity points if 500 or more, is not preferable for practical use since it is necessary for catalyst removal step exceeds 10 ^5.

The catalyst used in the present invention is prepared by mixing the catalyst components in any order, preferably in a hydrocarbon or halogenated hydrocarbon solvent. The catalyst may be prepared by mixing the respective components in advance before contacting it with the conjugated diene containing 1,3-butadiene as the main component of the present invention. It can also be prepared by mixing the components in the presence of a diene.

In the present invention, a conjugated diene containing 1,3-butadiene as a main component is added to the catalyst, that is, (A) to (D).
Polymerization is carried out in an inert organic solvent using a catalyst whose main component is. The polymerization solvent is an inert organic solvent,
For example, aromatic hydrocarbon solvents such as benzene, toluene, xylene, cumene, n-pentane, n-hexane, n-
Aliphatic hydrocarbon solvent such as butane, alicyclic hydrocarbon solvent such as methylcyclopentane, cyclohexane, cyclopentane, methylene chloride, chloroform, carbon tetrachloride,
Halogenated hydrocarbon solvents such as trichloroethylene, perchlorethylene, 1,2-dichloroethane, chlorobenzene, bromobenzene, chlorotoluene and mixtures thereof can be used.

The polymerization temperature is usually -50 ° C to 120 ° C.
And preferably -20 to 50 ° C. The polymerization reaction may be a batch system or a continuous system. The monomer concentration in the solvent is usually 5 to 50% by weight, preferably 10 to 35% by weight. Further, in order to produce a polymer, in order not to deactivate the catalyst and the polymer of the present invention, it is necessary to take into consideration the inclusion of a compound having a deactivating action such as oxygen or water in the polymerization system as much as possible. . When the polymerization reaction has proceeded to the desired stage, the reaction mixture is added with alcohol, another polymerization terminator, an antioxidant, an antioxidant, an ultraviolet absorber, etc., and then the produced polymer is separated, washed and dried according to a usual method. Thus, the desired butadiene-based polymer can be obtained.

According to the production method of the present invention, since a specific catalyst is used, a wide range of polymerization solvents can be used, and the obtained polymer has a high melting point, a narrow molecular weight distribution, and a high molecular weight. , 2-bond content. in this way,
The butadiene-based polymer obtained by using the catalyst containing the components (A) to (D) as a main component has a vinyl bond content in the butadiene portion of 80 to 97%, preferably 85 to 97%.
Further, the molecular weight of the butadiene-based polymer obtained in the present invention is such that the polystyrene-equivalent weight average molecular weight is usually 0.
5 × 10 ^{4 to} 100 × 10 ⁴ , preferably 2 × 10 ⁴ to
80 × 10 ⁴ , less than 0.5 × 10 ⁴ has poor mechanical properties, while more than 100 × 10 ⁴ has poor processability, excessive torque is applied during kneading with rolls or Banbury, and compounding It is not preferable because problems such as deterioration of the vulcanized rubber due to deterioration of the temperature of the product due to high temperature and poor dispersion of carbon black occur. Further, the melting point of the obtained butadiene-based polymer is 40 to 150 ° C, preferably 50 to 140 ° C.

Further, the butadiene-based polymer obtained in the present invention has a molecular weight distribution (M) represented by the ratio of polystyrene-reduced number average molecular weight (Mn) and weight average molecular weight (Mw).
w / Mn) can be varied over a wide range, but it is usually 1.5 to 5, and less than 1.5 is technically difficult unless a living polymerization technique is used, while 5
If it exceeds, the physical properties are poor and the low molecular weight increases, which is not preferable.

The butadiene-based polymer obtained by the present invention is blended as a raw rubber with the polymer alone or blended with other synthetic rubber or natural rubber, and if necessary, oil-extended with a process oil, and then, A rubber composition which is obtained by adding a filler such as carbon black, a vulcanizing agent, and a usual vulcanizing compounding agent such as a vulcanization accelerator into a rubber composition, and vulcanizing the composition to obtain mechanical properties and abrasion resistance. It can be used for applications such as tires, hoses, belts, and various other industrial products. The butadiene-based polymer obtained by the present invention can also be used as a rubber modifier by blending with other various rubbers.

[0024]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. In the examples, parts and% are based on weight unless otherwise specified.
In addition, various measurements in the examples were based on the following methods.
The weight average molecular weight and the number molecular weight were measured by gel permeation chromatography (GPC). The vinyl bond content of the butadiene-based polymer was determined by the infrared absorption spectrum method (Morero method). The glass transition point and the melting point are SSC5200H manufactured by Seiko Instruments Inc.
ASTM D34 using a DSC (differential scanning calorimeter)
It measured according to 18.

Reference Example (Preparation of 1,3-Butadiene, Catalyst and Polymerization Solvent) 1,3-Butadiene; 1,3-butadiene manufactured by Nippon Synthetic Rubber Co. Ltd.
The butadiene was used after being distilled and then dried using a molecular sieve 4A. Bis (triphenylphosphine) cobalt dibromide; the method described in the literature (J. Chatt et al., J. Che.
m. Soc. , 1961,285] was used as a dichloromethane solution. Methylaluminoxane; a toluene solution manufactured by Tosoh Akzo Co., Ltd. was used. Triisobutylaluminum; manufactured by Tosoh Akzo Co., Ltd. was used as a toluene solution. Polymerization solvent: Dry nitrogen was used, degassed, and then dried using molecular sieve 4A.

Examples 1 to 3 In a pressure resistant bottle having an internal volume of 100 ml, which was sufficiently replaced with nitrogen,
54 ml of toluene and 9.2 μl of water were added and stoppered. Next, 10 g of 1,3-butadiene was added and the mixture was mixed at 10 ° C. for 10 minutes.
Shake for a minute. Then, triisobutylaluminum, methylaluminoxane, and bis (triphenylphosphine) cobalt dibromide were added according to the polymerization recipe shown in Table 1, and polymerization was carried out at 10 ° C. for 30 minutes. 3 ml of methanol as a polymerization terminator was added to this polymerization system to terminate the polymerization, and then the polymerization solution was poured into a large amount of methanol containing an antioxidant at 40 ° C. to coagulate / precipitate, and the produced butadiene polymer was filtered. And separated by vacuum drying at 60 ° C. for 12 hours. The results are shown in Table 1.

Examples 4 to 6 Polymerization was carried out in the same manner as in Example 1 except that the polymerization solvent used in Example 1 was changed to cyclohexane, n-hexane and methylene chloride. The results are shown in Table 1.

Comparative Example 1 All of the organoaluminum [(B) to (C) components] used in Example 1 were replaced with triisobutylaluminum, and the amount of water added was changed to 1.0 in terms of molar ratio to triisobutylaluminum. A polymerization operation was performed in the same manner as in Example 1 except that the above was performed. The results are shown in Table 1. It can be seen that the polymerization activity is remarkably low when the organoaluminum is triisobutylaluminum alone.

Comparative Example 2 Except that the organoaluminum [(B) to (C) components] used in Example 1 were all replaced with methylaluminoxane.
Polymerization was carried out in the same manner as in Example 1. The results are shown in Table 1. It is found that when methylaluminoxane alone is used as the organoaluminum, the polymerization activity is high, but the melting point and molecular weight of the obtained butadiene polymer are low and the molecular weight distribution is rather wide.

Comparative Examples 3 to 4 Polymerization was carried out in the same manner as in Example 1 except that the organoaluminum [(B) to (C) components] used in Example 1 were used in the ratios shown in Table 1. It was The results are shown in Table 1. When the composition ratio of the organoaluminum is changed, the polymerization activity, the melting point of the obtained polymer, the molecular weight, or the molecular weight distribution is inferior, and the catalyst system used in the present invention has a good balance in any case. You can see that you cannot get it.

Comparative Examples 5 to 6 Polymerization was carried out in the same manner as in Example 1 except that the water (D) used in Example 1 was used in the ratio shown in Table 1. The results are shown in Table 1. It can be seen from Table 1 that when the ratio of (D) water is changed, the polymerization activity is significantly lowered, or there is a problem in controlling the high melting point and the high molecular weight.

[0032]

[Table 1]

[0032]

EFFECT OF THE INVENTION According to the method for producing a butadiene-based polymer of the present invention, by using a specific catalyst, it is highly active even in a hydrocarbon solvent, and the obtained butadiene-based polymer has a high melting point and a high molecular weight. A crystalline 1,2-polybutadiene polymer having a high molecular weight distribution and a high 1,2-bond content can be produced.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masahiro Shibata 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. Housing 1008

Claims (1)

[Claims] 1. A conjugated diene containing at least 50 mol% of 1,3-butadiene, (A) a cobalt compound, (B) aluminoxane, (C) trialkylaluminum and (D) water, And (B) / (C)
(Aluminum atomic ratio) is 0.1 to 10, (D) /
(C) (molar ratio) using a catalyst of 0.1 to 1.8,
A method for producing a butadiene-based polymer, which comprises polymerizing in an inert organic solvent.