JPH09302014A - Production of ethylene/aromatic vinyl compound copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an ethylene/aromatic vinyl compound copolymer in catalytic activity higher as compared with that of a conventional transition metal compound catalyst and favorable in the industry by using a specified metallocene compound as the catalyst. SOLUTION: An ethylene/aromatic vinyl compound is produced by using a catalyst being a metallocene compound represented by formula I [wherein A1 and A2 are each (substituted) cyclopentadienyl or (substituted) indenyl; Y and Y' are each a (substituted) alkylene, a [substituted] silylene or a (substituted) germanylene; M is a group IV metal; X and X' are each H, a halogen, an alkyl, an alkoxyl, an aryloxy or an amide] and a promoter comprising an organoaluminum compound [e.g. an aluminoxane represented by formula II or III (wherein R is a 1-5 C alkyl; and (m) and (n) are each 2-100] and/or a boron compound. The above process is freed from the drawbacks, such as low activity, of a conventional transition metal compound catalyst and is more suitable for industrial production.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an ethylene-aromatic vinyl compound copolymer.

[0002]

2. Description of the Related Art Conventionally, ethylene and aromatic vinyl compounds,
For example, styrene copolymers have been investigated using so-called heterogeneous Ziegler-Natta catalysts. However, the heterogeneous Ziegler-Natta catalyst system has low activity,
It is not practical because it has a low styrene content, contains a large amount of homopolymer, and does not have a uniform composition.

In addition, recently, JP-A-6-49132, JP-A-3-163088, and JP-A-7-536.
No. 18 discloses a method for producing an ethylene-styrene copolymer by using a catalyst made of a specific transition metal compound and a so-called homogeneous Ziegler-Natta catalyst system made of an organoaluminum compound as a cocatalyst. In these homogeneous Ziegler-Natta systems, for example, the method disclosed in JP-A-6-49132 is an industrial production method because the polymer yield per unit metal is low and a large amount of organoaluminum compound is required. It can not be said. Similarly, JP-A-3-163088 and JP-A-7-53.
In the method disclosed in Japanese Patent No. 618, in addition to requiring a large amount of organoaluminum, a large amount of syndiotactic polystyrene is by-produced in addition to the intended ethylene-styrene copolymer under mild reaction conditions. It is not an efficient manufacturing method.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing an ethylene-aromatic vinyl compound copolymer, which overcomes the disadvantages of the conventional transition metal compound catalysts and is more suitable for industrial production. Is.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the inventors have commercialized an ethylene-aromatic vinyl compound copolymer by using a specific Group 4 metallocene compound as a catalyst. The inventors have found that they can be produced with a suitable high activity, and completed the present invention.

The present invention will be described in detail below. In the following description, Me represents a methyl group and Ph represents a phenyl group.
The ethylene-aromatic vinyl compound copolymer production method of the present invention is a production method characterized by polymerizing using a catalyst system composed of a metallocene catalyst represented by the following general formula (1) and a cocatalyst. is there.

[0007]

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(In the formula, A1 and A2 each represent a group selected from a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group and a substituted indenyl group, and Y and
Y'is a group bridging A1 and A2 and represents a group selected from a substituted or unsubstituted alkylene group, a substituted or unsubstituted silylene group, a substituted or unsubstituted germanylylene group, and M is 4 in the periodic table. Group X metal, X, X '
Each represents a group selected from hydrogen, halogen, an alkyl group, an alkoxy group, an aryloxy group and an amide group. )

Here, A1 and A2, which may be the same or different, are a cyclopentadienyl group or a substituted cyclopentadienyl group, an indenyl group or a substituted indenyl group. The substituent that is substituted on the substituted cyclopentadienyl or substituted indenyl group is an alkyl group,
An alkenyl group, a halogen, an alkoxy group, an alkylated silyl group, and an alkylamino group are shown, and these may form a ring structure with each other. Examples of the substituted cyclopentadienyl group include a methylcyclopentadienyl group, a dimethylcyclopentadienyl group, a trimethylsilylcyclopentadienyl group, a substituted or unsubstituted tetrahydroindenyl group and the like.

Y and Y'represent a group bridging A1 and A2, that is, a substituent having a bond with A1 and A2, which may be the same or different. Y and Y ′ are a hydrogen atom or a substituted alkylene group substituted with an alkyl group or an aryl group, a hydrogen atom or an alkyl or aryl substituted silylene group, a substituted germanium or a substituted boron, for example, —CH ₂ CH ₂ —, —CH. _{2 -, - CMe 2 -,} - C
_{Ph 2 -, - CH 2 CHPh} -, - SiH 2 -, - SiM
_{e 2 -, - SiPh 2 -} , - GeMe 2 -, - BMe 2 - , and the like.

X and X'may be the same as or different from each other. X and X ′ are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group such as a methyl group, an ethyl group, a benzyl group and a bistrimethylsilylmethyl group, an alkoxy group such as a methoxy group and an isopropoxide group, 4-methyl-
An aryloxy group such as a 2,6-di-t-butylphenoxy group and a phenoxy group, and an amide group such as a bistrimethylsilylamide group and a dimethylamide group.

In the present invention, an organoaluminum compound and / or a boron compound is used as a promoter together with the above catalyst. Alumoxane is suitable as the organoaluminum compound used as a cocatalyst. Alumoxane is a cyclic or chain compound represented by the following general formulas (2) and (3). If desired, a mixture of these different types of alumoxanes may be used.

[0013]

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[0014]

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(In the formula, each R independently has 1 to 5 carbon atoms.
Is most preferably a methyl group having 1 carbon atom, and m and n each represent an integer of 2 to 100. Further, these alumoxanes and alkylaluminums such as trimethylaluminum, triethylaluminum, triisobutylaluminum and dimethylaluminum chloride may be used in combination.

The boron compound used as the cocatalyst is N,
Examples thereof include N-dimethylanilinium tetra (pentafluorophenyl) borate, trityl tetra (pentafluorophenyl) borate, tri (pentafluorophenyl) borate and the like. The boron compound and the organoaluminum compound may be used at the same time. Particularly when a boron compound is used as a co-catalyst, it is effective to add an alkylaluminum compound such as triisobutylaluminum to remove impurities such as water contained in the polymerization system, which adversely affect the polymerization.

Examples of the aromatic vinyl compound used in the present invention include styrene and various substituted styrenes such as p.
-Methylstyrene, o-methylstyrene, pt-butylstyrene, p-chlorostyrene, o-chlorostyrene and the like, and also compounds such as divinylbenzene having a plurality of vinyl groups in one molecule. However, styrene and p-methylstyrene are preferably used, and styrene is particularly preferably used.

In producing the copolymer of the present invention, a catalyst and a cocatalyst are brought into contact with ethylene and an aromatic vinyl compound, but a method of polymerizing in a liquid monomer without using a solvent, pentane, hexane, There is a method in which a saturated aliphatic or aromatic hydrocarbon such as heptane, cyclohexane, benzene, toluene, xylene, chloro-substituted benzene, and chloro-substituted toluene is used alone or in a mixed solvent. Further, if necessary, a method such as batch polymerization, continuous polymerization, batch polymerization, or preliminary polymerization can be used.

The polymerization temperature is suitably -78 ° C to 200 ° C, preferably 0 ° C to 160 ° C. Polymerization temperature is -78 ° C
Below, it is industrially disadvantageous, and above 200 ° C., decomposition of the catalyst which is a metal complex occurs, which is not suitable.

When an organoaluminum compound is used as a co-catalyst, the amount of aluminum atom / aluminum atom is
The metal atom ratio of the complex metal is 0.1 to 100,000, preferably 1
Used in ratios of ~ 1000. If it is less than 0.1, the metal complex cannot be effectively activated, and if it exceeds 100,000, it is economically disadvantageous.

When a boron compound is used as a cocatalyst, it is used at a boron atom / complex metal atom ratio of 0.01 to 100, preferably 0.1 to 10, particularly preferably 1. To be If it is less than 0.01, the metal complex cannot be effectively activated, and if it exceeds 100, it is economically disadvantageous. The catalyst of the present invention and the co-catalyst may be mixed and prepared outside the polymerization tank, or may be mixed inside the tank during the polymerization.

[0022]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the chemical formulas below, Cp represents a cyclopentadienyl group, Flu represents a fluorenyl group, and Me represents a methyl group.

The polymers obtained in the following Examples and Comparative Examples were analyzed by the following method. ^{The 13} C-NMR spectrum was measured by using JNM GX-270 or α-500 manufactured by JEOL Ltd. as a solvent.
The measurement was performed using tetrachloroethane. The analysis of the polymer was performed by setting the chemical shift of the peak of 1,1,2,2-tetrachloroethane remaining in the heavy solvent to 74.2 ppm and obtaining the chemical shift of each peak. The styrene content in the polymer was determined by ¹ H-NMR, and the instrument was JNM GX-270 or α-50 manufactured by JEOL Ltd.
0 was used, heavy 1,1,2,2-tetrachloroethane was used as a solvent, and the intensity of the peak derived from the phenyl group proton and the proton peak derived from the alkyl group was compared. The molecular weight of the polymer was determined by GPC (gel permeation chromatography) using THF as a solvent and HLC-8020 manufactured by Tosoh Corporation to calculate the weight average molecular weight in terms of standard polystyrene.

Example 1 (Catalyst production method) {((CH ₃ ) ₂
Si) ₂ Cp ₂ } ZrCl ₂ and Organometal
lics, vol. 13, 1994, page 1688. ^The compound was identified by ¹³ C-NMR spectrum.

[0025]

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(Polymerization) Ethylene-substituted capacity 120 m
10 ml of styrene and Methylalumoxane (MMAO-3A manufactured by Toso Akzo Co., Ltd.) were placed in an autoclave of 1 Al.
14mmol charged in atomic basis, of the dissolved in toluene _{16ml {((CH 3) 2} Si) 2 Cp 2} ZrCl 2
23 μmol was added, the pressure was immediately raised with ethylene, and then the reaction was carried out at 50 ° C. for 1 hour while maintaining ethylene at 5 atm. After completion of the reaction, the pressure of ethylene was released, and the content liquid was poured into a large excess of hydrochloric acid / methanol mixed liquid to recover a polymer. The polymer was dried under reduced pressure at 60 ° C. for 10 hours to obtain 6.2 g of the polymer. The styrene content in the polymer was 19%.

Comparative Example 1 [Flu-CMe _2- ] shown as the following chemical formula 6 as a complex
A polymerization operation was performed in the same manner as in Example 1 except that 23 μmol of Cp} ZrCl ₂ and 14 mmol of methylalumoxane were used on the Al atom basis, and 1.0 g of a white polymer was obtained.

[0028]

[Chemical 6]

The polymer obtained in Example 1 was derived from styrene-ethylene copolymerization as shown in FIG.
around ppm, around 27 ppm, around 37 ppm and 4
A peak around 6 ppm was observed, but no peak around 41 ppm derived from the head-tail styrene chain was observed. Therefore, it was confirmed that this was an ethylene-styrene random copolymer having no head-tail styrene chain. Was done. In addition, Comparative Example 1 using no catalyst of the present invention
It was confirmed that Example 1 can produce an ethylene-styrene copolymer with extremely high activity as compared with Example 1. The above test and analysis results are summarized in Table 1.

[0030]

[Table 1]

[0031]

INDUSTRIAL APPLICABILITY According to the present invention, by using a specific metallocene compound as a catalyst, only an ethylene-aromatic vinyl compound copolymer can be produced with a high activity suitable for industrialization as compared with conventional methods.

[Brief description of drawings]

1 is a schematic diagram of the ethylene-styrene random copolymer having no head-tail styrene chain obtained in Example 1. FIG.
¹³ C-NMR spectrum.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Akio Okamoto 3-5-1, Asahimachi, Machida-shi, Tokyo Denka Kagaku Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A method for producing an ethylene-aromatic vinyl compound copolymer, which comprises polymerizing using a metallocene catalyst represented by the following general formula (1) and an organoaluminum compound and / or a boron compound. . Embedded image (In the formula, A1 and A2 each represent a group selected from a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, and a substituted indenyl group. Y and Y ′ are groups that bridge A1 and A2. Represents a group selected from a substituted or unsubstituted alkylene group, a substituted or unsubstituted silylene group, a substituted or unsubstituted germanylylene group, M represents a Group 4 metal in the periodic table, and X and X ′ represent Each represents a group selected from hydrogen, halogen, an alkyl group, an alkoxy group, an aryloxy group, and an amide group, and A1 and A.
2, Y and Y ', X and X'may be the same or different from each other. ) Wherein Y, Y 'is the formula (-Si (CH _3)
The method of producing an ethylene-aromatic vinyl compound copolymer according to claim 1, wherein M is zirconium, which is a group represented by _2- ). 3. The method for producing an ethylene-aromatic vinyl compound copolymer according to claim 1 or 2, wherein the aromatic vinyl compound is styrene.