JPH05331226A - Production of polyolefin - Google Patents

Abstract

PURPOSE:To produce a polyolefin with higher activity by using a catalyst formed from a specific transition metallic compound and an aluminoxane and polymerizing an olefin in the presence of hydrogen. CONSTITUTION:An olefin is polymerized in the presence of hydrogen (in an amount of 0.01-70mol% the hydrogen in the vapor-phase part) by using a catalyst composed of (A) a transition metallic compound of the formula (A<1> is cyclopentadienyl, indenyl, fluorenyl group or a derivative thereof; A<2> is disubstituted fluorenyl group; A<3> and A<4> are 1-10C alkyl, 6-20C aryl, alkylaryl, etc.; Q is 1-10C hydrocarbon group, hydrocarbon group containing Si, etc., connecting A<1> to A<2>; R<1> and R<2> are halogen, H, 1-10C alkyl, etc.; M is titanium, zirconium or hafnium) (e.g. a metallocene compound) and (B) an aluminoxane (preferably methylaluminoxane) in a molar amount of usually 10-10000 times based on the component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing a polyolefin. More specifically, it relates to a method for producing a polyolefin with higher activity using a catalyst composed of metallocene / aluminoxane.

[0002]

PRIOR ART Cyclopentadienyl group, indenyl group,
It is known that a transition metal compound having a fluorenyl group or a derivative thereof as a ligand, a so-called metallocene compound, can be used together with a cocatalyst such as an aluminoxane to polymerize an α-olefin to produce a poly-α-olefin. ing. JP-A-58-19309 and JP-A-60-35008 describe a method of polymerizing or copolymerizing an olefin in the presence of a catalyst composed of a metallocene compound and an aluminoxane. JP-A-61-130314, JP-A-64-6
Japanese Patent No. 6124 describes that a poly-α-olefin having a high degree of isotacticity can be produced by using a catalyst composed of a metallocene compound having a crosslinkable ligand and an aluminoxane.

Japanese Unexamined Patent Publication Nos. 2-41303 and 2-
JP-A-274703 and JP-A-2-274704 disclose that a syndiotactic poly-α-olefin is produced by using a metallocene compound having a crosslinkable ligand composed of asymmetrical ligands and a catalyst composed of an aluminoxane. It is described that it is possible. On the other hand, the active species of the above-mentioned so-called Kaminsky type catalyst is [C
p since _'2 MR] ⁺ (wherein Cp' = cyclopentadienyl derivatives, M = Ti, Zr, Hf , R = alkyl) it is suggested a transition metal cation such as represented by, aluminoxanes Some catalyst systems that do not use as a cocatalyst have been reported. Taube et al. J. Organometall. Che
m., 347 , C9 (1988) [Cp ₂ TiMe (THF)]
⁺ [BPh ₄ ] ^- (Me = methyl group, Ph = phenyl group) was used to successfully polymerize ethylene. Jordan et al., J. Am. Chem. Soc., 109 , 4111 (19
87) shows that zirconium complexes such as [Cp ₂ ZrR (L)] ⁺ (R = methyl group, benzyl group, L = Lewis base) polymerize ethylene.

Japanese Patent Publication No. 1-501950, Japanese Patent Publication No. 1-501950
-502036 describes a method for polymerizing olefins using a catalyst composed of a cyclopentadienyl metal compound and an ionic compound capable of stabilizing a cyclopentadienyl metal cation. Zambel
li et al. reported in Macromolecules, 22 , 2186 (1989) that isotactic polypropylene can be produced using a catalyst that combines a zirconium compound having a cyclopentadiene derivative as a ligand and trimethylaluminum and fluorodimethylaluminum. is doing. JP-A-3-179005 discloses an olefin polymerization catalyst comprising a) a neutral metallocene compound, b) aluminum alkyl, and c) Lewis acid. The above-mentioned so-called Kaminsky type catalyst has a problem that a large amount of expensive aluminoxane must be used in order to exhibit high activity.

[0005]

The so-called Kaminsky type catalyst composed of the metallocene compound / aluminoxane as described above generally requires the use of a large amount of aluminoxane in order to obtain high activity. Therefore, the activity per aluminoxane was extremely low. Therefore, it was necessary to further improve the catalytic activity in order to improve the activity per aluminoxane.

[0006]

Means for Solving the Problems The inventors of the present invention have made extensive studies on a method for solving the above problems and further improving the polymerization activity. As a result, a catalyst composed of a special metallocene and an aluminoxane was used under specific conditions. It was found that the above-mentioned object was achieved by polymerizing the olefin with the above method, and the present invention was completed. That is, the present invention provides (A) general formula [I]

[0007]

[Chemical 2] (Here, A ¹ represents a cyclopentadienyl group, an indenyl group, a fluorenyl group, or a derivative thereof, and A 1
² represents a 2-substituted fluorenyl group. A ³ and A ⁴ are an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group, a halogenated aryl group or a hetero atom such as oxygen, nitrogen, sulfur or silicon. Is a hydrocarbon group or a hydrogen atom containing.
Q is a hydrocarbon group having 1 to 10 carbon atoms connecting A ¹ and A ² or a hydrocarbon group containing silicon, germanium and tin. Also, A ^3, A ⁴ is A ³ be linked to each other, A
^A ring structure may be formed between ⁴ and Q. R ¹ , R ²
Represents a halogen atom, a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, or an arylalkyl group. M is titanium, zirconium, or hafnium. ) Is used in the presence or absence of an organoaluminum compound, and a catalyst formed from a transition metal compound represented by the formula (B) and an aluminoxane are used to polymerize an olefin in the presence of hydrogen. It is a manufacturing method.

Controlling the molecular weight of a polymer obtained by polymerizing an olefin in the presence of hydrogen using a catalyst composed of a metallocene compound / aluminoxane is
For example, it is publicly known as described in JP-A-2-274703. However, in the case of conventional catalysts, when polymerization is carried out in the presence of hydrogen, the polymerization activity is hardly changed or the activity is largely decreased, and it was practical to control the molecular weight by using hydrogen. In the present invention, by selecting and using a specific metallocene compound, it is possible to dramatically improve the activity by adding hydrogen and polymerizing. When the polymerization is carried out in the presence of a very small amount of hydrogen, the activity of the resulting polymer is increased substantially without lowering the molecular weight, and by increasing the amount of hydrogen present, the polymerization activity is improved and the molecular weight can be controlled.

In the general formula [I], A ¹ represents a cyclopentadienyl group, an indenyl group, a fluorenyl group, or a derivative thereof. Specifically, a cyclopentadienyl group,
Methylcyclopentadienyl group, dimethylcyclopentadienyl group, tetramethylcyclopentadienyl group, indenyl group, 3-methylindenyl group, tetrahydroindenyl group, fluorenyl group, methylfluorenyl group,
2,7-di-t-butylfluorenyl group, octahydrofluorenyl group and the like can be mentioned. A ² represents a 2-substituted fluorenyl group. Specifically, a 2-substituted fluorenyl in which a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, a butyl group, a cyclohexyl group, and a phenyl group is introduced at the 2,7-position or the 3,6-position of a fluorenyl group. It is a base. Among them, those in which the substituent is located at the 2,7-position are preferably used, and a preferable example thereof is 2,7-di-t.
A butyl fluorenyl group. A ³ and A ⁴ are alkyl groups having 1 to 10 carbon atoms, aryl groups having 6 to 20 carbon atoms, alkylaryl groups, arylalkyl groups, halogenated aryl groups, or heteroatoms such as oxygen, nitrogen, sulfur and silicon. Is a hydrocarbon group or a hydrogen atom. Specific examples of A ³ and A ⁴ include hydrogen atom, methyl group, ethyl group, propyl group, phenyl group, toluyl group,
Examples thereof include a fluorophenyl group, a methoxyphenyl group and a benzyl group. Q is a hydrocarbon group having 1 to 10 carbon atoms connecting A ¹ and A ² , or a hydrocarbon group containing silicon, germanium or tin, preferably a hydrocarbon group or a silicon atom. A ³ and A ⁴ may be linked to each other to form a ring structure between A ³ , A ⁴ and Q, and in such a case, as a group formed by A ³ , A ⁴ and Q, Examples thereof include a cyclopentylidene group, a cyclohexylidene group, and a tetrahydropyran-4-ylidene group. R ¹ and R ² are a halogen atom, a hydrogen atom,
An alkyl group having 1 to 10 carbon atoms, a silicon-containing alkyl group, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, and an arylalkyl group are shown. Preferable specific examples of R ¹ and R ² include chlorine atom, methyl group, phenyl group,
Examples thereof include a trimethylsilylmethyl group.

Specific examples of the metallocene compound represented by the general formula [I] in the present invention include JP-A-4-69.
The metallocene compound as described in Japanese Patent No. 394 can be mentioned. Specific examples of such a compound include, for example, isopropylidene (cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, cyclohexylidene (cyclopentadienyl) (2,7- Di-t-butyl-9-fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-dit-butyl-9-fluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7 -Di-t-butyl-9-fluorenyl) zirconium dichloride, dimethylsilylene (cyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, isopropylidene (methylcyclopentadienyl)
(2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, cyclohexylidene (methylcyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diphenylmethylene (methylcyclopenta) Dienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, methylphenylmethylene (methylcyclopentadienyl)
(2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, dimethylsilylene (methylcyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, isopropylidene (tetramethylcyclopenta) Dienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, cyclohexylidene (tetramethylcyclopentadienyl)
(2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, diphenylmethylene (tetramethylcyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride, methylphenylmethylene (tetramethyl Cyclopentadienyl) (2,
Examples thereof include 7-di-t-butyl-9-fluorenyl) zirconium dichloride and dimethylsilylene (tetramethylcyclopentadienyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride.
These compounds can be easily prepared by a method according to the synthesis example of isopropylidene (cyclopentadienyl) (2,7-dit-butyl-9-fluorenyl) zirconium dichloride described in JP-A-4-69394. Can be synthesized.

The aluminoxane used as the component (B) in the present invention has the following general formula (Formula 3).

[0012]

[Chemical 3] (Wherein R represents a hydrocarbon group having 1 to 10 carbon atoms, and n represents 2 or more), and particularly methylaluminoxane in which R is a methyl group, n is 5 or more, preferably 10 or more. Are used. The aluminoxane may be mixed with some alkylaluminum compound. In addition, in addition to the above, JP-A-2-24701
Aluminoxane having two or more kinds of alkyl groups described in JP-A No. 3-103407 and the like, fine-particle aluminoxane described in JP-A No. 63-198691, and JP-A No. 2-167302.
Aluminum oxy compounds and the like, which are obtained by contacting aluminoxane described in JP-A No. 2-167305 and water with an active hydrogen compound, can also be suitably used.

The ratio of aluminoxane to the transition metal compound used in the present invention is 1 to 100,000.
The molar ratio is usually 10 to 10,000 times. The transition metal compound and / or aluminoxane in the present invention may be used as it is, or may be used by supporting it on a known carrier supporting a Ziegler type catalyst such as SiO ₂ , Al ₂ O ₃ and MgCl ₂ . The transition metal compound / aluminoxane catalyst of the present invention can be used in the presence of an organoaluminum compound, if necessary. By doing so, it is possible to produce a polyolefin with a smaller amount of aluminoxane used. As the organoaluminum compound used, the general formula ^{_{R 1 j Al (OR 2)}} k H l X m ( wherein R ^1, R ² represents a hydrocarbon group having up to 20 carbon atoms, R ^1, R ² may be the same or different from each other, X is a halogen atom, O is an oxygen atom, H is a hydrogen atom, j is an integer from 1 to 3, and k, l and m are from 0 to 2. And j + k + l + m = 3). Specific examples include trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum chloride, ethylaluminum dichloride, diisobutylaluminum hydride and the like. Among them, triethylaluminum and triisobutylaluminum are preferably used.

What is important in the present invention is to polymerize propylene in the presence of hydrogen. By doing so, the catalytic activity is dramatically increased, and by changing the amount of hydrogen added, it is possible to produce a polyolefin having a desired molecular weight. The amount of hydrogen added can be selected in the range of 0.01 to 70 mol% of hydrogen in the gas phase, and when the amount added is small, it is effective only for improving the activity, and when added in a large amount, the activity The molecular weight can be controlled simultaneously with the improvement. In the method of the present invention, the amount of hydrogenation can be kept constant during the polymerization, or the amount of hydrogenation can be changed during the polymerization to broaden the molecular weight distribution of the produced polymer.

There are no particular restrictions on the polymerization method and the polymerization conditions used in the method of the present invention, and known methods used in the polymerization of olefins can be used, including a solvent polymerization method using an inert hydrocarbon medium or a substantially non-existent method. A bulk polymerization method or a gas phase polymerization method in which an active hydrocarbon medium does not exist can also be used, and it is general to carry out at a polymerization temperature of −100 to 200 ° C. and a polymerization pressure of atmospheric pressure to 100 kg / cm ² . The pressure is preferably −50 to 100 ° C. and atmospheric pressure to 50 kg / cm ² . Examples of the hydrocarbon medium used in the polymerization in the present invention include saturated hydrocarbons such as butane, pentane, hexane, heptane, octane, nonane, decane, cyclopentane, and cyclohexane, and aromatics such as benzene, toluene, and xylene. Hydrocarbons can also be used. As olefins used in the polymerization, ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1
-Dodecene, 1-tetradecene, 1-hexadecene, 1
Mention may be made of C2-C25 olefins such as octadecene. In the present invention, it can be used not only in homopolymerization of olefins, but also in the case of using copolymers of olefins having about 2 to 25 carbon atoms such as propylene and ethylene and propylene and 1-butene. Also, the method of the present invention can be applied to the copolymerization with a diene for the purpose of modifying the polyolefin. Examples of the diene compound used at that time include 1,4-hexadiene, 4-methyl-1,4-hexadiene, ethylidene norbornene, and dicyclopentadiene.

[0016]

EXAMPLES The present invention will be specifically described below with reference to examples. Example 1 Isopropylidene (cyclopentadienyl) synthesized by a method described in JP-A-4-69394 in an autoclave of 1.5 dm ^{3 which} is fully nitrogen-substituted.
(2,7-Di-t-butyl-9-fluorenyl) zirconium dichloride 0.3 mg and Tosoh Akzo Co. methylaluminoxane 64 mg were charged, followed by liquid propylene 0.75 dm ³ and gas phase hydrogen concentration. 1v
Hydrogen was added so that it would be ol%. After 30 minutes of polymerization at 40 ° C., the polymerization was stopped by adding a small amount of methanol to the system, unreacted propylene was purged and dried to obtain 122.6 g of syndiotactic polypropylene powder. It was This corresponds to an activity of 805 kg (polypropylene) / g (transition metal catalyst) · h. The intrinsic viscosity ([η]) of the obtained powder measured with a 135 ° C. tetralin solution was 1.02 dl / g, ¹³ C
-Syndiotactic pentad fraction (rrrr) measured by NMR is 0.91, melting point (Tm) measured using a differential scanning calorimeter is 151 ° C, measured by gel permeation chromatography (GPC) The polydispersity index (Mw / Mn) was 2.2.

Example 2 In the method of Example 1, the hydrogen concentration in the gas phase was adjusted to 15 vol.
Polymerization was carried out under exactly the same conditions except that the percentage was changed to 1
20.3 g of syndiotactic polypropylene powder was obtained. This is kg (polypropylene) / g
(Transition metal catalyst) -corresponds to the activity of h. The intrinsic viscosity ([η]) of the obtained powder measured with a 135 ° C. tetralin solution was 0.82 dl / g, the syndiotactic pentad fraction (rrrr) measured with ¹³ C-NMR was 0.90, and the differential Melting point (T measured using a scanning calorimeter
m) was 151 ° C.

Comparative Example 1 Propylene was polymerized in the same manner as in Example 2 except that hydrogen was not used, and 41.2 g of syndiotactic polypropylene powder was obtained. This is 270
This corresponds to an activity of kg (polypropylene) / g (transition metal catalyst) · h. [Η] of the obtained powder is 1.04d.
1 / g, rrrr 0.90, melting point (Tm) 150
The degree of dispersion and the molecular weight dispersity (Mw / Mn) were 2.1. Thus, in the case of Example 1 in which hydrogen was added at the time of polymerization, it was found that the activity was about 3 times that of this Comparative Example, and the addition of hydrogen was extremely effective in improving the activity.

Comparative Example 2 1 mg of isopropylidene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride synthesized by the method described in JP-A-2-41303 as a transition metal catalyst component and methylaluminoxane as a co-catalyst component of 0. Polymerization of propylene was carried out in the same manner as in Example 1 except that 27 g was used and the polymerization time was 1 hour.
28.8 g of syndiotactic polypropylene powder was obtained. This is 29 kg (polypropylene) / g
(Transition metal catalyst) -corresponds to the activity of h. [Η] of the obtained powder was 1.29 dl / g, and rrrr was 0.8.
9, melting point (Tm) 145 ° C., molecular weight dispersity (Mw / M
n) was 2.1. As described above, even if a transition metal compound other than the present invention was used, it was not possible to produce a polyolefin with high activity.

[0020]

EFFECT OF THE INVENTION By carrying out the method of the present invention, a polyolefin having a higher activity can be produced, which is extremely valuable industrially.

Claims (1)

[Claims] 1. (A) General formula [I] (Chemical formula 1)(Where A¹Is a cyclopentadienyl group, indenyl
Group, a fluorenyl group or a derivative thereof,²
Represents a 2-substituted fluorenyl group. A³, A^FourHas 1 carbon
Alkyl groups of up to 10 and aryls of 6 to 20 carbon atoms
Group, alkylaryl group, arylalkyl group, halo
Aryl groups or oxygen, nitrogen, sulfur, silicon, etc.
It is a hydrocarbon group containing a hetero atom or a hydrogen atom. Q
Is A¹, A ²Hydrocarbons having 1 to 10 carbon atoms that connect
A group or a hydrocarbon group containing silicon, germanium or tin.
It Also, A³, A^FourAre connected to each other and³，
A^Four, Q may form a ring structure. R¹, R
²Is a halogen atom, a hydrogen atom, or an atom having 1 to 10 carbon atoms.
Alkyl group, aryl group having 6 to 20 carbon atoms, alkyl
An aryl group and an arylalkyl group are shown. M is titanium,
Zirconium and hafnium. ) Transition money
The catalyst formed from the genus compound and (B) aluminoxane is treated with an organic alkane.
Used in the presence or absence of a minium compound, hydrogen
Characterized by polymerizing olefins in the presence of
Process for producing olefin.