JPH0725835B2 - Polymerization method of propylene - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for polymerizing propylene. Specifically, it relates to a method for polymerizing propylene using a solid catalyst having a magnesium halide obtained by a specific method as a carrier.

[Conventional technology]

For the polymerization of olefins, it is known to use a catalyst composed of a transition metal catalyst in which a titanium halide is supported on a carrier such as magnesium halide and a catalyst composed of an organometallic compound in Japanese Patent Publication No. 39-12
Since its disclosure in No. 105, various improved methods have been proposed, and fairly excellent performances have been obtained.

[Problems to be solved by the invention]

The above-mentioned improved method is mainly to add a crusher to obtain a carrier and grind it, or to dissolve magnesium halide used as a carrier in a solvent and then precipitate it, thereby carrying a transition metal and a catalyst for olefin polymerization. In order to obtain excellent performance, the carrier is treated so that the diffraction line measured by X-ray diffraction has no clear peak and is observed as halo-. In particular, the method of dissolving and then depositing is excellent,
Highly active catalysts can be produced (see, for example, JP
56-11908). However, this method has a problem in that a large amount of a precipitant is required and that a product having good activity cannot be obtained unless it is repeatedly treated with titanium halide.
Further, the method of adding additives and pulverizing has a problem in that it is inferior to the above-mentioned method of dissolving and precipitating in that it provides polypropylene having high activity and high stereoregularity per transition metal catalyst.

[Means for solving problems]

The present inventors have conducted extensive studies on a method for solving the above problems, found that a solid catalyst having titanium halide supported on magnesium halide produced by a specific method is suitable, and completed the present invention. .

That is, the present invention is a method of polymerizing propylene using a catalyst comprising a transition metal catalyst component and an organoaluminum compound, wherein the transition metal catalyst component is magnesium halide and the following general formula [1] RnSi (OR ') _4- n [ 1] (wherein R and R ′ are hydrocarbon residues having 1 to 20 carbon atoms, and n is 0
An integer of 3) and a solid catalyst component obtained by heating a co-ground product of an alkoxy silicon compound with a mixture of titanium chloride and phthalic acid diester.

In the present invention, as the magnesium halide, magnesium chloride, magnesium bromide, magnesium iodide,
Alternatively, a mixture or mixed crystal thereof can be used, and an anhydride or one containing water up to several wt% can be used.
This magnesium halide is first co-ground with an alkoxy silicon compound. As the alkoxy silicon compound, an organic silicon compound having at least one alkoxy group is used and is represented by the general formula; RnSi (OR ') _4- n (wherein R and R'are hydrocarbon residues, preferably 1 to 20 carbon atoms). Is a hydrocarbon residue of and a compound represented by n is an integer of 0 to 3, and specifically, as the hydrocarbon residue, a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, Examples thereof include a heptyl group, a phenyl group and a substituted phenyl group. The ratio of the alkoxy silicon compound to the magnesium halide is generally 0.01 to 0.5 parts by weight based on 1 part by weight of the magnesium halide. When co-milling, a part of the alkoxy silicon compound, that is, 0 to 90% by weight of the alkoxy silicon compound, is converted into another electron donating compound, specifically, an oxygen-containing compound such as ester, ether, orthoester, an amine. , A nitrogen-containing compound such as amide, or a phosphorus-containing compound such as phosphoric acid ester or phosphite ester. At that time, the alkoxy compound is at least 1 part by weight of magnesium halide to 1 part by weight of magnesium halide.
It is preferably 0.01 part by weight or more. Co-milling can be carried out by a known milling means such as a ball mill and a vibration mill, and the milling time is usually from 1 to 1000 hours although it cannot be specified depending on the equipment used for milling or the temperature. It is also possible to use other compounds, for example, a hydrocarbon compound, a halogenated hydrocarbon compound, or a polymer thereof, or silicone oil, etc. in the co-milling.

In the present invention, as titanium chloride, titanium tetrachloride or titanium trichloride liquefied with an electron donating compound is preferably used. Usually, titanium chloride is used in excess with respect to the co-ground product and the phthalic acid diester described below, and it is general to use 1 to 1000 parts by weight per 1 part by weight of the co-ground product.

Specific examples of the phthalic acid diester include methyl, ethyl, propyl, butyl, pentyl, hexyl and heptyl esters, and even if the two alkyl groups are the same,
It can be different. As a usage ratio with respect to the co-ground product, it is general to use about 0.01 to 0.5 parts by weight per 1 part by weight of the co-ground product.

In the present invention, the mixture of titanium chloride and phthalic acid diester and the co-ground product are heat treated, the heat treatment is usually performed at 50 to 200 ° C., and the time is generally several minutes to several hours. At this time, titanium chloride may be diluted with a hydrocarbon compound or a halogenated hydrocarbon compound before use. Of course, the heat treatment can be repeated once or more. After the heat treatment, the solid content and the liquid are separated, and the solid content is washed with a hydrocarbon compound as necessary to form the solid transition metal catalyst of the present invention.

In the present invention, propylene can be polymerized using the solid transition metal catalyst and the catalyst composed of an organoaluminum compound.

Here, as the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkylaluminum sesquihalide, and alkylaluminum dihalide can be used, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, and a hexyl group. Examples of halides include chlorine, bromine, and iodine.

At this time, a stereoregularity improver, for example, the compounds listed as the above-mentioned electron-donating compounds can also be used in combination during the polymerization, which is effective for improving the stereoregularity of polypropylene. , Oxygen-containing compounds such as esters, orthoesters and alkoxy silicon compounds are preferable.

In the present invention, the polymerization of propylene may be carried out in a hydrocarbon solvent, for example, in an inert medium such as pentane, hexane, heptane, decane, benzene, toluene, xylene, etc., or a bulk polymerization method using propylene itself as a liquid medium, or It can also be carried out by a gas phase polymerization method in which a liquid medium does not substantially exist, and the polymerization temperature is room temperature to 100 ° C. and the polymerization pressure is normal pressure to 50 kg / cm ² gauge.

The present invention is not limited to homopolymerization of propylene, but also copolymerization with a small amount up to several% of other α-olefins such as ethylene, and in the latter stage, ethylene or other α-olefin, if necessary, is not added to the polymerized polymer. It can also be applied to the production of a so-called block copolymer, which is a copolymerization that accounts for 20 to 95 wt% of the coalescence.

〔Example〕

 Hereinafter, the present invention will be further described with reference to examples.

Example 1 A crusher equipped with two crushing pots having an internal volume of 1 and containing 2 kg of steel balls having a diameter of 12 mm was prepared, and 20 g of anhydrous magnesium chloride, 2 ml of tetraethoxysilane, and 1 ml of ethyl orthoacetate were placed in each pot. Add 40 ml of ethylene dichloride 40
Co-milled for hours. 10 g of the obtained co-ground product was put in a 200 ml flask, 80 ml of titanium tetrachloride, 20 ml of toluene and 5 ml of di-n-butyl phthalate were added, and the mixture was stirred at 120 ° C. for 1 hour, then left to stand and the supernatant was removed. Titanium chloride 80 ml, toluene 2
0 ml was added and the mixture was stirred at 120 ° C. for 1 hour. After standing to remove the supernatant, the solid content was washed with n-heptane to obtain titanium content of 3.2 wt.
% Transition metal catalyst was obtained. 20 mg of this transition metal catalyst component,
0.15 ml of triethylaluminum, 0.03 ml of trimethoxyphenylsilane and 100 ml of n-heptane are mixed to make a catalyst slurry, put into an autoclave with an internal volume of 5, 1.8 kg of propylene and 3.3 Nl of hydrogen are added, and a polymerization reaction is carried out at 75 ° C for 2 hours. I went. After the polymerization reaction, the unreacted propylene was purged and the polymer was taken out and dried at 80 ° C. and 60 mmHg for 12 hours to obtain 920 g of powder. The intrinsic viscosity of the obtained polymer (measured with a tetralin solution at 135 ° C., hereinafter abbreviated as η) and the extraction residual ratio when extracted with a Soxhlet extractor for 6 hours with boiling n-heptane (hereinafter referred to as II and The powder weight after extraction / the powder weight before extraction is expressed as a percentage), and η was 1.82 and II was 98.2%.

Comparative Example 1 Polypropylene powder (480 g) was obtained in the same manner as in Example 1 except that ethyl alcohol was used instead of tetraethoxysilane. The powder had an η of 1.72 and an II of 94.9%.

Example 2 In Example 1, when di-n-butyl phthalate was replaced with isopropyl phthalate, polypropylene powder 86 was obtained.
I got 0g. The powder had an η of 1.68 and an II of 97.9%.

Example 3 Co-milled with triethoxyethylsilane 4 ml, propane chloride 3 m
The same procedure as in Example 1 was carried out except that 20 g of magnesium chloride containing 1% of water was used. 980 g of polypropylene powder was obtained, and η of the powder was 1.76 and II was 98.2%.

〔The invention's effect〕

By carrying out the method of the present invention, it is possible to produce polypropylene having a high stereoregularity with a high yield per catalyst, which is extremely valuable industrially.

[Brief description of drawings]

FIG. 1 is a flow chart diagram for helping understanding of the present invention.

Claims (1)

[Claims] 1. A method for polymerizing propylene using a catalyst comprising a transition metal catalyst component and an organoaluminum compound, wherein the transition metal catalyst component is magnesium halide and the following general formula [1] RnSi (OR ') _4- n [. 1] (wherein R and R ′ are hydrocarbon residues having 1 to 20 carbon atoms, and n is 0
Is an integer of 3), and is a solid catalyst component obtained by heat-treating a co-ground product of an alkoxy silicon compound with a mixture of titanium chloride and phthalic acid diester.