JPH047306A - Preparation of syndiotactic poly-alpha-olefin - Google Patents

Abstract

PURPOSE:To improve the yield per unit wt. of catalyst, particle size, and bulk density of a resulting polymer by polymerizing an alpha-olefin in the presence of a specific catalyst. CONSTITUTION:One mol of a transition metal compd. having an asymmetric ligand and pref. comprising a compd. of formula I (wherein A and B are each an arom. hydrocarbon group; R is a 1-20C hydrocarbon residue or an Si compd. connecting A to B; X is halogen or a 1-20C hydrocarbon residue; and M is Ti, Zr, or Hf) and 1-1000000mol of an aluminoxane comprising a compd. of formula II or III (wherein R is a 1-3C hydrocarbon residue) are deposited on an inorg. oxide having hollows in its inside, thus giving a catalyst component is compound with an organoaluminum compd. (e.g. triethylaluminum) to give a catalyst. In the presence of the catalyst, an alpha-olefin is polymerized under normal to 100kg/cm<2> pressure at -100 to 200 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing syndiotactic polyα-olefins. Specifically, the present invention relates to a method for producing a syndiotactic poly-α-olefin with a high yield per catalyst, a relatively large particle size, and a high bulk specific gravity.

[Prior art]

The existence of syndiotactic polypropylene has been known for a long time, but the conventional low-temperature polymerization method using a catalyst consisting of a vanadium compound, ether, and organoaluminium has poor syndiotacticity, and the characteristics of syndiotactic polypropylene It was difficult to say that it represented the On the other hand, J. A. EWEN et al. reported that a catalyst consisting of a transition metal compound having an asymmetrical ligand and an aluminoxane has a good toughness with a syndiotactic pentad fraction exceeding 0.7. It was discovered for the first time that polypropylene could be obtained (
J,^m,ches,soc,,1988,110.6
255-6256).

Furthermore, the present inventors have found that syndiotactic poly-α-olefins can be similarly obtained by polymerizing other α-olefins in a similar manner.

[Problem to be solved by the invention]

The above-mentioned method by J, A, EWEN et al. has good activity per transition metal, and is an excellent method in which the obtained polymer has high toughness, but the particle size of the obtained polymer is small and the bulk specific gravity is low. There were problems in that productivity was poor due to the small size, poor properties of the polymerization slurry, and inability to remove polymerization heat.

[Means for Solving the Problems] The present inventors solved the above problems and produced polyα-olefins with high activity, relatively large particle size, high bulk specific gravity, and high syndiotacticity with good productivity. The present invention was completed after intensive study on the method for doing so.

That is, the present invention provides a method for polymerizing α-olefin using a catalyst consisting of a transition metal compound having an asymmetric ligand and aluminoxane, in which a transition metal compound having an asymmetric ligand and aluminoxane are supported on an inorganic oxide. The present invention is a method for producing a syndiotactic polyα-olefin, which is characterized by using a catalyst consisting of an organic aluminum catalyst and an organoaluminum catalyst.

As the transition metal compound used in the present invention, the compounds described in the above-mentioned documents can be exemplified. A hydrocarbon residue or a compound containing silicon; X is a halogen atom or a hydrocarbon residue having 1 to 20 carbon atoms; ■ is a metal atom selected from titanium, zirconium, and hafnium;

) can be preferably used. Examples of A and B include monocyclic or polycyclic aromatic compounds having 5 to 30 carbon atoms, and specifically, cyclopetadiene or a part or all of the hydrogens thereof being an alkyl group having 1 to 10 carbon atoms. Substituted (here, the alkyl group may have a structure in which its terminal is bonded to the cyclopentadiene ring again),
Examples include polycyclic aromatic compounds such as indene and fluorene, and compounds in which part or all of the hydrogen atoms thereof are substituted with an alkyl group having 1 to 10 carbon atoms. R is preferably a dialkylmethylene group or a dialkylsilylene group,
For example, compounds represented by R'zC, R'zSi (wherein R' is hydrogen or an alkyl residue having 1 to 20 carbon atoms and may be the same or different) can be preferably used, but -CR' An example is an ethylene group represented by -CR''- (in the formula, R' is the same as above). Examples include aromatic compounds such as a pentagenyl group, with chlorine and methyl groups being particularly preferred.

Examples include compounds represented by 17 R (wherein R is a hydrocarbon residue having 1 to 3 carbon atoms), and in particular, methylaluminoxane in which R is a methyl group and n is 5 or more is used. The ratio of aluminoxane to the above transition metal compound is 1 to 100.
0,000 mol times, usually 10 to 5,000 mol times.

What is important in the present invention is to support the above-mentioned transition metal compound and aluminoxane on an inorganic oxide, and to use an organoaluminum compound described below in combination during polymerization.
2, CaO1NazO1K20, MgO.

Various oxides such as MnO, TiO□, and ZrO□ with cavities inside, those with relatively large pores and a large surface area can be preferably used, and hollow inorganic oxides, oxide gels, etc. can be used. It can be done, and the diameter is usually 1μ to 0.1+*
A material of about s+ can be preferably used. Especially AIz
Those containing Oz are preferred, and are preferred because they enable the supported amounts of the transition metal compound and aluminoxane to be increased.

The inorganic oxide may be used after being further calcined before supporting the transition metal compound or aluminoxane, and it is preferable to use the inorganic oxide after removing at least free water.

There are no particular restrictions on the method of supporting, but in order to effectively utilize the hollow space, the process of dispersing the hollow inorganic oxide in a solution of the transition metal compound and aluminoxane, reducing the pressure of the system, and then returning it to normal pressure is repeated. This allows for effective support. In addition, in order to support the inorganic oxide on the carrier surface, the inorganic oxide is dispersed in a solution of a transition metal compound and aluminoxane, and then a poor solvent for aluminoxane (usually a lower hydrocarbon compound such as pentanehexane is used) is added. This is achieved by depositing a transition metal compound on a carrier.

Usually, after being supported, the catalyst is washed with the lower hydrocarbon compound used for precipitation to remove unsupported catalyst, and then used for polymerization. There is no particular restriction on the temperature at which the support is carried out, but it is usually carried out at O''C to 100C.

It is also possible to use aluminoxane as an organoaluminum compound used in combination with the supported catalyst during polymerization, but aluminoxane is usually expensive, and trialkylaluminium, which has 2 to 3 bonded alkyl residues having 12 to 12 carbon atoms,
Dialkyl aluminum halides and the like can be used.

In the present invention, α-olefins include propylene, butene-1, pentene-1, hexene-1, heptene-1
, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1
1. In addition to linear α-olefins such as pentadecene-1, hexadecene-1, and octadecene-1, branched α-olefins such as 3-methylbutene-1,4-methylpentene-1,4,4-dimethylpentene-1 are exemplified, and these α-olefins are shown not only singly but also in mixtures with each other or with a small amount of ethylene.

There are no particular restrictions on the polymerization conditions, and solvent polymerization using an inert medium, bulk polymerization without an inert medium, and gas phase polymerization can also be used.The polymerization temperature is -100 to 200°C. Polymerization pressure is normal pressure ~ 1
00 kg/cj is common. Preferably, the temperature is -100 to 100°C and normal pressure to 50 kg/d.

〔Example〕

The present invention will be further explained with reference to Examples below.

Example 1 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride 200+ag obtained by reacting isopropylcyclopentagenyl-1-fluorene synthesized according to a conventional method with lithiated silica-tetrachloride and Toyo Akzo Dissolve 34 g of methylaluminoxane (polymerization degree 16.2) manufactured by ■ in 300 d of toluene and put it in a flask No. 101, and add 1 liter of Sankilite YO4 manufactured by Sanki Kogyo ■ (calcined at 600°C for 10 hours).
An operation of dispersing 0 g of the mixture, reducing the pressure to 80 mmHg using a vacuum pump and holding it for 10 minutes while stirring, and then returning to normal pressure and holding it for 10 minutes was repeated 5 times. It was then filtered under a nitrogen stream to remove excess isopropyl (cyclopentadienyl-1-
fluorenyl) zirconium dichloride methylaluminoxane was removed. The supported catalyst was then washed five times with 100 d of toluene to obtain a supported catalyst. This catalyst contained 0.04 wtx zirconium.

0.5 g of the catalyst thus obtained was placed in an autoclave with an internal volume of 21 m, and 0.17 m of triethylaluminum and 1 ml of toluene.
1 and polymerized at 20'C for 2 hours without adding propylene so that the polymerization pressure was 3 kg/cj-G, then deashed with methanol and methyl acetoacetate, washed with an aqueous hydrochloric acid solution, and then After filtration and drying, 47.0 g of polymer was obtained (corresponding to 235,000 g polypropylene/1 g of zirconium). The bulk specific gravity of this polymer is 0.40g/m1, and the average particle size is 420μ
It was m. According to "C-NMR, the syndiotactic pentad fraction is 0.92, and the intrinsic viscosity (hereinafter referred to as η) measured in a tetralin solution at 135°C is 1.
．． 42.1, 2.4-) The ratio of the weight average molecular weight to the number average molecular weight measured with dichlorohensen (hereinafter referred to as MW/M
(denoted as N) was 2.3.

Comparative Example 1 The same procedure as Example 1 was carried out except that triethylaluminum was not used during polymerization, and only 20.5 g of syndiotactic polypropylene was obtained (this was
The bulk specific gravity of this polymer was 0.37 g/d and the average particle size was 400 μ-.

Also, according to 3C-NMR, the syndiotactic pentad fraction is 0.92 Te, η is 1.42, and MW/M.
N was 2.2.

Comparative Example 2 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride obtained in Example 1 was added to 1.0
Example 1 was repeated except that 0.17 g of methylaluminoxane and 0.17 g of methylaluminoxane were used.
2 g were obtained (this corresponds to 241 000 g polypropylene/zirconium tg). The bulk specific gravity of this polymer was 0.218/d and the average particle size was 50 μm. According to 13C-NMR, the syndiotactic pentad fraction was 0.92, η was 1.40, and MW/MN was 2.3.

Example 2 0.5 g of the catalyst obtained in Example 1 and 0.2 d of triethylaluminum were placed in a 52 autoclave and 1 d of propylene was added.
．． 5 kg was added and polymerized at 60°C for 2 hours, unreacted propylene was purged, the polymer was taken out, dried, and weighed to obtain 342 g of polymer. η of polymer
was 0.87, bulk specific gravity was 0.34 g/d, and syndiotactic pentad fraction was 0.82.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 2 without using triethyl aluminum to obtain 127.4 g of polymer.

Polymer η is 0.90, bulk specific gravity is 0.328/IIJ
l, the syndiotactic pentad fraction was 0.83.

Example 3 Methylaluminoxane manufactured by Toyo Akzo ■ (polymerization degree 16.2
) to 40 m of 20-tχ solution of A1 manufactured by Nippon Aerosil Co., Ltd.
2g of ua+inium oxide C calcined at 450°C was added and stirred for 15 minutes, then 40d of n-pentane was added and allowed to stand, and about 40ml of supernatant was removed. Next, 500 m of isopropyl (cyclopentadienyl-1 fluorenyl) zirconium dichloride obtained in Example 1 was added.
g is methylaluminoxane manufactured by Toyo Akzo (polymerization degree 16).
．． 2) (7) Dissolved in 40d of 20@tX solution 1. f, -
was added and stirred at room temperature for 1 hour, then 40d of n-
After adding pentane and stirring for 10 minutes, the solid component obtained by filtration with a glass filter was further washed with 100-n-pentane to obtain a catalyst. 485 was prepared in the same manner as in Example 2 except that 0.2 g of this catalyst was used and 0.2 d of triisobutyl aluminum was used instead of triethyl aluminum.
g of polymer was obtained. The polymer had a η of 0.86, a bulk specific gravity of 0.34 g/d, and a syndiotactic pentad fraction of 0.80.

Comparative Example 4 The same procedure as Example 3 was carried out except that the polymerization was performed without using triisobutylaluminum, and 215 g of polymer was obtained.
Obtained. The polymer has a η of 0.87 and a bulk specific gravity of 0.34 g/
d, syndiotactic pentad fraction was 0.81.

〔Effect of the invention〕

By carrying out the method of the present invention, a syndiotactic polyα-olefin having high activity per catalyst and a large bulk specific gravity can be obtained, which is extremely valuable industrially.

[Brief explanation of drawings]

FIG. 1 is a flow diagram to aid understanding of the present invention. Patent applicant: Mitsui Toatsu Chemical Co., Ltd. 1st (A) Transition metal component

Claims (1)

[Claims] In a method for polymerizing α-olefin using a catalyst consisting of a transition metal compound having an asymmetrical ligand and aluminoxane, a catalyst comprising a transition metal compound having an asymmetrical ligand and aluminoxane supported on an inorganic oxide and an organic aluminum are used. A method for producing a syndiotactic polyα-olefin, the method comprising using a catalyst comprising: