JPS63305107A - Polymerization of propylene - Google Patents

Abstract

PURPOSE:To obtain a polypropylene which is excellent in physical properties and is highly crystalline, by polymerizing propylene using a catalyst comprising a specific transition metal catalyst and an organic Al compound. CONSTITUTION:TiCl3 (a) obtained by reduction of TiCl4 with H2, metallic Al or an organic Al is mixed with talc (b) in a ratio of a to b of 1,000-1/1, and if desired, an electron donating compound (c) (e.g., an ester, a phosphoric ester, etc.) is added thereto with the proportion of the component (c) to the component (a) of 0.001-1.0mol. to 1mol., and they are ground together to obtain a transition metal catalyst (A). The catalyst (A) is washed with an inert solvent, and mixed with an organic Al compound (B) such as a dialkylaluminum halide to obtain a polymerization catalyst for propylene. Propylene is polymerized using the catalyst, for example, in a hydrocarbon solvent, at room temperature - 100 deg.C under ordinary pressures - 50kg/cm<2>G.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for polymerizing propylene. Specifically, the present invention relates to a method for producing highly crystalline polypropylene using a specific catalyst.

[Conventional technology]

Although polypropylene is a polymer with excellent rigidity, there is a problem in that the degree of crystallinity of molded products is relatively low, and the physical properties of ordinary molded products are inferior to the originally expected physical properties. To solve this problem, a method of adding various nucleating agents is usually used, and molded bodies with excellent rigidity and transparency are obtained.

(Problems to be Solved by the Invention) Although the method of adding a nucleating agent is simple and effective, it is necessary to add a relatively large amount of nuclei, and as a result, the physical properties of the molded product may deteriorate due to poor dispersion of the nucleating agent. There are problems such as variations in the nucleating agent and bleeding of the added nucleating agent, and it is known that this can be solved by adding a specific polymer compound, but a more effective method is desired.

[Means for solving problems]

The present inventors have diligently searched for a more effective method and have arrived at the present invention.

That is, the present invention is a method for polymerizing propylene using a catalyst consisting of a transition metal catalyst and an organoaluminum compound, which is characterized in that a solid catalyst obtained by co-pulverizing talc and titanium trichloride is used as the transition metal catalyst. This is a method for producing highly crystalline polypropylene.

The present invention is characterized by the use of a transition metal catalyst, and more specifically, by using a specific co-pulverized titanium trichloride catalyst.

Titanium trichloride used for co-pulverization in the present invention includes:
Those produced by various production methods can be used, such as titanium trichloride obtained by reducing titanium tetrachloride with hydrogen, metal aluminum, or organic aluminum, or a eutectic of titanium trichloride and aluminum chloride. The talc used for co-pulverization is usually a rock called katzite, which is refined and pulverized as necessary.

Here, the ratio of talc and titanium trichloride is usually 1:1.
000~1:1, preferably 5:100
~1:2.

In the present invention, when co-pulverizing talc and titanium trichloride, electron-donating compounds, specifically oxygen-containing compounds such as esters, ethers, orthoesters, alkoxy silicon,
It is preferable to use nitrogen-containing compounds such as amines and amides, and phosphorus-containing compounds such as phosphoric acid esters and phosphorous esters in combination, thereby improving the stereoregularity of the polypropylene obtained or the activity per transition metal catalyst. Can be done. ii) The proportion of the electron donating compound to be used is about 0.001 to 1.0 mol, preferably about 0.05 to 0.5 mol, per 1 mol of titanium trichloride.

In the present invention, the co-pulverized product is then mixed with an inert solvent, such as a hydrocarbon compound such as pentane, hexane, heptane, decane, benzene, toluene, xylene, ethylbenzene, cumene, methyl chloride, ethyl chloride, ethylene dichloride, chlorobenzene, etc. The performance can be further improved by cleaning with a halogenated hydrocarbon compound such as.

In the present invention, propylene is polymerized using a catalyst consisting of the above-mentioned transition metal catalyst and an organoaluminum compound. As the organoaluminum compound, trialkylaluminum, dialkylaluminum halide, alkyl aluminum sesquihalide, and alkyl aluminum civalide are used. Examples of the alkyl group include a methyl group, ethyl group, propyl group, butyl group, and hexyl group, and examples of the halide include chlorine, bromine, and iodine, with dialkyl aluminum halides being particularly preferred.

At this time, a stereoregularity improver 1, for example, one of the compounds mentioned above as the electron-donating compound, which is effective in improving the stereoregularity of the polypropylene obtained when used in combination during polymerization, can also be used in combination.

Here, preferred examples of the stereoregularity improver include oxygen-containing compounds such as ethers, esters, orthoesters, and alkoxy silicon compounds.

In the present invention, propylene polymerization may be carried out in an inert medium such as a hydrocarbon solvent such as pentane, hexane, heptane, decane, benzene, toluene, or xylene, or by a bulk polymerization method using propylene itself as a liquid medium. Alternatively, the polymerization can be carried out by a gas phase polymerization method in which no liquid medium is present, and the polymerization temperature is normal temperature to 100° C., and the polymerization pressure is normal pressure to 50 kr/d gauge.

The present invention is directed not only to homopolymerization of propylene but also to copolymerization with a small amount of up to several percent of other α-olefins such as ethylene, or in a subsequent stage where ethylene or other α-olefins are added to the polymer in the corresponding part. It can also be applied to the production of so-called block copolymers, in which copolymerization is carried out in such a manner that 20 to 95 wt% of

〔Example〕

Hereinafter, the present invention will be further explained by citing examples.

Example 1 Internal volume 0.97 containing 2.2 kg of steel balls with a diameter of 12 am
3. Prepare a vibrating mill equipped with two grinding pots (1) and place 30 g of titanium trichloride (TAC-141 manufactured by Toho Titanium ■) and talc (JA-13R manufactured by Asada Seifun ■) in each pot under a nitrogen atmosphere. 0g, tetraethoxysilane 4
was added and ground for 40 hours. Put 10g of the co-pulverized product thus obtained into a 200ml flask and add 10g of heptane.
0 was added, stirred at 90"C for 30 minutes, then left to stand, the clear liquid was removed, and the same operation of adding 100% heptane and washing was repeated three times to obtain a transition metal catalyst slurry. Into a flask with an internal volume of 200" Butane 100 under nitrogen atmosphere
+sl, the above transition metal catalyst Loom g, diethylaluminum chloride 2.0, p-)methyl ruylate 0. After adding lO and mixing, this catalyst slurry was placed in an autoclave with an internal volume of 51 kg, and propylene was mixed with 1.8 kg of propylene.
After the polymerization reaction, unreacted propylene was purged, and the taken out polymer was dried at 80°C with 5Qs+mt1g for 12 hours to obtain 320g of polymer. Got the powder.

The intrinsic viscosity of the obtained powder in a tetralin solution at 135°C (hereinafter abbreviated as 1) and boiling n-hebutane
The extraction residual rate (hereinafter abbreviated as II, expressed as a percentage of powder weight after extraction/powder weight before extraction) when extracted with a time Soxhlet extractor was measured. In addition, a 10/10,000 weight ratio of phenolic stabilizer and a 15/10,000 weight ratio of calcium stearate were added to some of the powder, and the powder was granulated and the melt flow index was measured. Furthermore, an injection sheet with a thickness of 1 crane was made and bent. The stiffness was measured.

Melt flow index (Ml) AST
M 01238 (230℃) Bending rigidity
The melting point and crystal temperature were measured as the maximum peak temperature by raising or lowering the temperature at 10° C./1 lin using a differential thermal analyzer according to ASTM D747-63 (20° C.).

The results are shown in the table.

Comparative Example 1 340 g of polypropylene was obtained in the same manner as in Example 1 except that talc was not used. The physical properties of the obtained polypropylene were measured in the same manner as in Example 1.

The results are shown in the table.

Comparative Example 2 Granulation was performed in the same manner as in Example 1, except that 300 pp- of talc was added to polypropylene powder obtained by polymerization in the same manner as in Comparative Example 1, and the physical properties of the obtained pellets were measured.

The results are shown in the table.

Example 2 A transition metal catalyst was obtained in the same manner as in Example 1, except that ethyl benzoate 6 was used instead of tetraethoxysilane during co-pulverization, and polypropylene powder was polymerized in the same manner as in Example 1.
I got 20g. The physical properties of the obtained polymer were measured in the same manner as in Example 1. The results are shown in the table.

〔Effect of the invention〕

By implementing the method of the present invention, it is possible to produce polypropylene with excellent physical properties, and it is extremely valuable industrially.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram to aid understanding of the present invention.

Claims (1)

[Claims] 1. In a method for polymerizing propylene using a catalyst consisting of a transition metal catalyst and an organoaluminum compound, a solid catalyst obtained by co-pulverizing talc and titanium trichloride is used as the transition metal catalyst. Characteristic method for producing highly crystalline polypropylene. 2. The method according to claim 1, in which co-pulverization is carried out in the presence of an electron-donating compound.