JPH0713106B2 - 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 producing a highly crystalline polypropylene by a specific polymerization method.

[Conventional technology]

Polypropylene is a polymer having excellent rigidity and is used for various purposes. However, since impact resistance (especially at low temperature) is poor, block copolymerization with other olefins such as ethylene has been performed to improve impact resistance (for example, Japanese Patent Publication No. 44-20621). , Shokoku Sho 49-2
4593 bulletin, Japanese Patent Publication No. Sho 49-12589, etc. ). By the way, when block copolymerization is performed, the impact resistance is inevitably improved, and accordingly the rigidity becomes poor. Therefore, improving the rigidity of polypropylene itself is extremely important not only for improving the physical properties of polypropylene but also for improving the physical properties of the block copolymer of propylene.

[Problems to be Solved by the Invention] It is known that the rigidity of a crystalline polymer such as polypropylene is correlated with the degree of crystallization of the polymer. Improve
It is common practice to improve the rigidity of polymers. However, the method of adding this nucleating agent is also ineffective unless a relatively large amount of nucleating agent is added, and when a large amount of nucleating agent is added, unevenness in the partial physical property balance of the molded product occurs due to uneven distribution of the nucleating agent As a result, there was a problem that the balance of physical properties of the molded product was poor, and that the nucleating agent bleeds and the appearance of the molded product is poor.

[Means for solving problems]

The present inventors have earnestly studied a method for solving the above problems and completed the present invention.

That is, in the present invention, when propylene is polymerized using a catalyst composed of a transition metal catalyst component containing trivalent and / or tetravalent titanium halide and an organoaluminum compound,
A method for producing a highly crystalline polypropylene, which comprises subjecting a catalyst to contact treatment with indene in advance and then polymerizing propylene.

The catalyst comprising the transition metal catalyst component and the organoaluminum compound used in the present invention is not particularly limited, and various known catalyst systems which give polypropylene with high stereoregularity can be used. Titanium halide is preferably used as the transition metal catalyst component, for example, titanium tetrachloride obtained by reducing titanium tetrachloride with metallic aluminum, hydrogen or organic aluminum, or those modified with an electron donating compound and organic aluminum. Compound Further, if necessary, a catalyst system comprising a stereoregularity improving agent such as an oxygen-containing organic compound, a carrier such as magnesium halide, or a product obtained by treating them with an electron-donating compound and carrying titanium halide. A catalyst system composed of an organoaluminum compound and, if necessary, a stereoregularity improving agent such as an oxygen-containing compound can be exemplified, and various examples are described in the following documents. Ziegler-Natta Catalysts and Polymerizat
ion by John Borr Jr. (Academic Rress), Journal of
Macromoleculer Sience-Reviews in Macromolecular
Chemistry and Physics C24 (3) 355-385 (1984), i
bid, C25 (1) 57-97 (1985), etc.

As the stereoregularity improver or electron donor, oxygen-containing compounds such as ethers, esters, orthoesters, and alkoxysilicons can be preferably used. As the electron donor, alcohol, aldehyde, water and the like can also be used.

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

Preferred titanium halides are aluminum or titanium trichloride obtained by reducing titanium tetrachloride with organic aluminum, modified by ether or ester, and magnesium chloride and an organic compound co-ground. What was treated with titanium, the reaction product of magnesium chloride and alcohol was dissolved in a hydrocarbon solvent and then treated with a precipitating agent such as titanium tetrachloride to make it insoluble in the hydrocarbon solvent, and if necessary, electrons such as ester and ether Examples thereof include supported titanium halides obtained by a method of modifying with a donor compound and then treating with titanium tetrachloride.

What is important in the present invention is that the catalyst is previously treated with indene. In this case, the use ratio of the organoaluminum compound / transition metal catalyst component may be the same as or less than that in the subsequent polymerization of propylene, and the amount ratio is 0.5 to 1000. Is generally used, and a stereoregularity improver can be present in that case, and the preferable ratio thereof is 0.01 to 300.

The contact treatment temperature and the contact treatment time are not particularly limited, but generally, the temperature is the same as or lower than the temperature during the polymerization of propylene, and the contact treatment time is several minutes to several hours. Is generally used, and the treatment is preferably performed under the condition that 0.001 weight ratio or more and 200 weight ratio or less of indene reacts with the transition metal catalyst component. This catalytic treatment is carried out in an inert medium for the Ziegler-Natta catalyst, such as pentane, hexane, heptane, octane, nonane, decane, benzene, toluene, xylene, ethylbenzene or a mixture thereof, and if necessary, unreacted indene It can also be used for the polymerization of propylene by removing and washing it, and further adding an organoaluminum compound.

If the reaction amount of indene per transition metal catalyst component is less than 0.001 weight ratio, the effect of the present invention is not sufficient, and if it exceeds 200 weight ratio, the problem that the surface becomes defective when the obtained polypropylene is formed is not preferable. .

In the present invention, the polymerization of propylene can be carried out in the above-mentioned inert medium, or can be carried out by a bulk polymerization method using propylene itself as a liquid medium, or a gas phase polymerization method in the absence of a substantially liquid inert medium. The polymerization temperature is normal temperature to 100 ° C. The polymerization pressure is normal pressure to 50 kg / cm ² · gauge.

In the present invention, not only propylene homopolymerization but also copolymerization with other α-olefins such as ethylene in a small amount up to several% or ethylene or, if necessary, other α-olefins in the core portion at a later stage is not necessary. It can also be applied to the production of so-called block copolymers in which copolymerization is performed so as to account for 20 to 95 wt% of the coalescence.

〔The invention's effect〕

By carrying out the method of the present invention, a highly crystalline polypropylene can be easily produced, which is extremely significant industrially.

〔Example〕

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

Example 1 i) Preparation of catalyst A vibration mill equipped with four grinding pots with an inner volume of 4 containing 9 kg of steel balls having a diameter of 12 mm is prepared. 300 g magnesium chloride and tetraethoxysilane in a nitrogen atmosphere in each pot
Add 60 ml and 45 ml of α, α, α-trichlorotoluene, and add 40
Crushed for hours.

300 g of the above co-ground product was placed in a flask of 5 and titanium tetrachloride was added.
After adding 1.5 and toluene 1.5 and stirring at 100 ° C for 30 minutes, leave still, remove the resulting supernatant liquid twice, and then wash the solid content with 4 n-heptane.
Repeated 10 times. When a part of the obtained solid catalyst slurry was sampled and analyzed, the titanium content was 1.9% by weight.

ii) Polymerization reaction In a flask with an internal volume of 200 ml, under a nitrogen atmosphere, 40 ml of toluene,
20 mg of the above solid catalyst, diethylaluminum chloride.
128 ml, 0.04 ml of methyl p-toluate, 0.03 ml of triethylaluminum and 0.2 g of indene were added, the mixture was stirred at 40 ° C. for 30 minutes, and 0.05 ml of triethylaluminum was added. This catalyst slurry was placed in an autoclave with an internal volume of 5, and 1.8 kg of propylene and 3.3 Nl of hydrogen were added, and the temperature was 75 ° C.
The polymerization reaction was carried out for 2 hours. After the polymerization reaction, unreacted propylene was purged, and the polymer was taken out at 80 ° C and 60 mmHg.
It was dried for 12 hours. 390 g of powder were obtained. The intrinsic viscosity (hereinafter abbreviated as η) measured with a tetralin solution at 135 ° C. and the ratio of the extraction residual rate (hereinafter abbreviated as II) when extracted with boiling Soxhlet extractor for 6 hours were measured. Next, a phenolic stabilizer was added in a weight ratio of 10/10000 and calcium stearate was added in a weight ratio of 15/10000, and the mixture was granulated and melt flow index (hereinafter abbreviated as MI. ASTM D-12
38), an injection sheet having a thickness of 1 mm was further prepared, and the flexural rigidity (ASTM D-747) was measured. or,
The melting point and crystallization temperature were measured as the maximum peak temperature by raising or lowering the temperature at 10 ° C./min using a differential thermal analyzer. The results are shown in the table.

A model experiment was conducted without polymerizing propylene, and the polymerization amount of indene with respect to the transition metal catalyst component was measured. As a result, the ratio was 0.7 weight ratio to the transition metal catalyst component.

Comparative Example 1 475 g of polypropylene was obtained in the same manner as in Example 1 except that the contact treatment with indene was not carried out. Various physical properties measured for the obtained polypropylene are shown in the table.

Example 2 0.08 ml of triethylaluminum for contact treatment with indene
Was performed in the same manner as in Example 1 except that 1.1 weight ratio of indene was polymerized with respect to the transition metal catalyst component, and the amount of polypropylene obtained was 405 g. Various physical properties measured for the obtained polypropylene are shown in the table.

Example 3 A commercially available highly active titanium trichloride (TAC-S-21 manufactured by Toho Titanium Co., Ltd.) was used as a transition metal catalyst component, and toluene 5 was used.
The above highly active titanium trichloride (100 mg), diethylaluminum chloride (2.0 ml) and indene (1.0) in 0 ml were contact-treated at 40 ° C. for 1 hour. Then, this slurry was put into an autoclave with an internal volume of 5, and 1.8 kg of propylene and 4.4 Nl of hydrogen were added.
Is added and the polymerization reaction is carried out at 75 ° C for 4 hours to obtain polypropylene 83
I got 0g. The polypropylene was treated in an autoclave in the presence of propylene oxide at 100 ° C. for 1 hour, and then granulated in the same manner as in Example 1 to measure the physical properties. The results are shown in the table. The polymerization amount of indene was 1.2 equivalents per titanium trichloride catalyst component.

Comparative Example 2 The same as Example 3 except that indene was not used. The results are shown in the table.

Comparative Example 3 The procedure of Example 1 was repeated except that the amount of indene used was 0.5 mg. The results are shown in the table. At this time, the polymerization amount of indene per titanium trichloride catalyst component was less than 0.001.

[Brief description of drawings]

FIG. 1 is a flow chart of the Ziegler catalyst according to the present invention.

Claims (2)

[Claims] 1. When polymerizing propylene using a catalyst comprising a transition metal catalyst component containing a trivalent and / or tetravalent titanium halide and an organoaluminum compound, propylene is prepared by contacting the catalyst with indene in advance. A method for producing a highly crystalline polypropylene, which comprises polymerizing polypropylene. 2. An indene content of 0.001 relative to a transition metal catalyst component containing trivalent and / or tetravalent titanium halide.
The method according to claim 1, wherein the contact treatment is carried out under a reaction condition of about 200 to 200 weight ratio.