JP2818264B2 - Propylene polymerization method - Google Patents

Description

The present invention relates to a method for polymerizing propylene. For more information,
The present invention relates to a method of treating a supported transition metal catalyst by a specific method to give propylene having high stereoregularity without a change over time of the catalyst.

(Prior art)

The method of polymerizing propylene using a catalyst comprising a transition metal compound supported on a carrier such as magnesium halide and a catalyst comprising an organometallic compound has undergone many improvements since its disclosure in JP-B-39-12105. The improvement is mainly in the direction of what to use as the electron donating compound used on the carrier side and the electron donating compound used in combination with the transition metal catalyst component and the organometallic compound, and also how to produce the transition metal catalyst component. In two directions. Among these, a bifunctional compound is used as the electron donating compound used on the carrier side, and an alkoxysilicon compound or a sterically hindered amine compound is used as the electron donating compound used in combination with the transition metal catalyst component and the organometallic compound. The method used is an excellent method which gives polypropylene having high activity and extremely high stereoregularity (for example, JP-A-58-138710, JP-A-59-117509, and JP-A-59-117509).
59-206407, 59-206410).

[Problems to be solved by the invention]

However, even in the case of a transition metal catalyst component using the above bifunctional compound, if the catalyst is directly introduced into a polymerization tank set at a high temperature near the polymerization temperature, the activity and stereoregularity of the obtained polymer are not sufficient. There is a problem, for which a small amount of propylene is polymerized, but those treated in this way have a problem that the performance changes over time and the performance deteriorates, especially when trialkylaluminum is used as the organoaluminum, Further, a method for providing a polypropylene having a higher stereoregularity has been desired.

[Means for solving the problem]

Means for Solving the Problems The present inventors have solved the above-mentioned problems, and have earnestly studied a method of using a high-performance transition metal catalyst component to provide a polypropylene having a high stereoregularity without changing over time, and completed the present invention.

That is, the present invention relates to a method for polymerizing propylene using a catalyst comprising a transition metal catalyst component in which a titanium compound is supported on a magnesium halide and an organoaluminum compound, wherein, as the transition metal catalyst component, magnesium halide and a diester of phthalic acid are used. Using a catalyst component containing a tetravalent titanium compound having at least one halogen, 0.1 to 100 g of propylene per magnesium halide in the catalyst component is polymerized in the presence of a trialkylaluminum compound and an alkoxysilicon compound. A method for polymerizing propylene, characterized by using a material obtained by adding 0.05 to 10 times titanium tetrahalide per trialkylaluminum used in the polymerization.

In the present invention, as the magnesium halide,
Substantially anhydrous magnesium halides can be used, even those containing several percent or less of water. Specifically, magnesium chloride, magnesium bromide, or a eutectic of magnesium chloride and magnesium bromide can be used.

As diesters of phthalic acid, phthalic acid and C1
Esters with alcohols of ~ 12 are preferably used, dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, diphenyl phthalate, dibenzyl phthalate,
In addition to di-2-ethylhexyl phthalate and the like, diesters such as butylbenzyl phthalate and ethylhexyl phthalate in which alcohols forming two ester bonds are different can also be used.

As the tetravalent titanium compound having at least one halogen used in the present invention, chlorine is preferably exemplified as halogen, and alkoxychlorotitanium is preferably used, and titanium tetrachloride is particularly preferably used.

There are no particular restrictions on the method for producing the catalyst component containing a divalent ester of magnesium halide and phthalic acid and a tetravalent titanium compound having at least one halogen, and various known methods can be employed. A method of co-milling a diester and other additives as necessary and then treating with a titanium halide, or a method of co-milling the above three components and treating with an aromatic hydrocarbon, or a method of converting a magnesium halide into a hydrocarbon with an alcohol or the like. It can be produced by a method of solubilizing in a solvent and then precipitating with a titanium halide or the like, treating the precipitate with or after the precipitation, treating with a diester of phthalic acid, and further treating with a titanium halide. If necessary, silica,
An inert inorganic compound such as alumina or a high molecular compound such as polyethylene, polypropylene and polystyrene can be used in combination.

In the present invention, the transition metal catalyst component produced by the above method is then used in the presence of a trialkylaluminum and an alkoxysilicon compound described below in an amount of 0.1 to 1 per magnesium.
Treated with 00 g of propylene. At this time, the treatment temperature is preferably 40 ° C. or lower, and the polypropylene obtained when treated at a temperature higher than 40 ° C. has poor stereoregularity, and more preferably −70 ° C. to 30 ° C.

The amount of the trialkylaluminum used is not preferably too large, and is usually 0.01 to 100 per atom of titanium.
It is molar times. If it is less than 0.01 mole times, polymerization is not preferred even if propylene is introduced, and if too much organoaluminum is used, the activity of the resulting catalyst slurry will be drastically reduced. More preferably, it is about 0.1 to 30 mol.

The use ratio of the alkoxysilicon compound is preferably 1 to 100 mol times per 1 atom of titanium, and if less than 1 mol time, there is no effect of improving stereoregularity, and if it is more than 100 mol times, it is particularly effective. Not economical, and 1 to 10 per mole of trialkylaluminum used here
It is preferable to use 0 mole times. The polymerization amount of propylene is preferably about 0.1 to 100 g per 1 g of magnesium halide in terms of introduction into the polymerization system, and 0.1 g or less is not preferable because the bulk specific gravity of the obtained polymer is small,
If the amount is 100 g or more, it is difficult to introduce a catalyst into the polymerization system, and the effect of treating with propylene is not necessarily increased. This treatment is preferably carried out in a hydrocarbon compound having 3 to 20 carbon atoms such as butane, pentane, hexane, heptane, octane, benzene, toluene, xylene, and ethylbenzene. In consideration of the concentration of the magnesium halide, it is preferable to set the magnesium halide to about 0.1 to 100 g / about.

In the present invention, trialkylaluminum is used for the treatment of a small amount of propylene. However, as an organoaluminum compound used for the subsequent polymerization described later, trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, and tributylaluminum are preferably Is used. As the alkoxysilicon compound, an organic silane compound containing 1 to 4 alkoxy groups is preferably used, and as the alkoxy group, those having a structure in which oxygen is bonded to an alkyl or alkenyl group having 1 to 12 carbon atoms are exemplified. The remaining groups include 1 to 12 alkyl groups or alkenyl groups.

In the present invention, titanium tetrahalide is added to the slurs thus treated with propylene. The addition amount is 0.05 to 10 times the molar amount of the trialkylaluminum used in the treatment of a small amount of propylene,
More preferably, it is 0.1 to 2 mole times. If the amount is less than 0.05 mol, there is no effect of reducing the change over time of the slurry, and if it is too large, it is not more effective.

In the present invention, the transition metal catalyst component slurry thus obtained is then used for the original polymerization at a higher temperature with the addition of an organoaluminum. As the added organoaluminum, usually, the organoaluminum is used in an amount of 10 to 10,000 mol times with respect to 1 mol of titanium.
This organoaluminum can be introduced into the polymerization system separately from the catalyst component slurry treated with propylene.

In the present invention, the above-mentioned alkoxysilicon compound can be further added at the time of polymerization, but it is preferable that the amount be about 5 to 1000 moles per 1 mole of titanium, together with the amount used before.

Here, the molar ratio of the organoaluminum and the stereoregularity improver is preferably about 1: 0.01 to 1:10 in terms of activity and stereoregularity of the obtained polymer.

In the present invention, the polymerization method in the course of the polymerization of propylene is not particularly limited, and various known methods can be adopted, and a solvent polymerization method using an inert hydrocarbon as a medium and a bulk polymerization method using liquid propylene as a medium. Any method of a gas phase polymerization method in which a liquid medium is not substantially present can be adopted. Temperature to 150 DEG ° C. at a temperature higher than the temperature during the processing of a small amount of propylene upon polymerization is generally carried out at a pressure of normal pressure to 100 kg / cm ^2, in addition to ethylene homopolymerization of propylene, butene, This polymerization method can be preferably employed for random copolymerization with other olefins such as pentene and hexene, or block copolymerization.

〔Example〕

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

Example 1 A vibration mill equipped with four crushing pots having an inner volume of 4 and containing 9 kg of steel balls having a diameter of 12 mm was prepared. 300 g of magnesium chloride, 115 ml of diisobutyl phthalate, and 60 ml of titanium tetrachloride were added to each pot in a nitrogen atmosphere, and pulverized for 40 hours. 10 g of the co-ground product was placed in a 200 ml flask, 40 ml of toluene was added, and the mixture was heated under boiling toluene and stirred for 30 minutes. Then, the supernatant was removed at 100 ° C., and the procedure of adding 100 ml of toluene, stirring at 100 ° C., and then allowing to stand still to remove the supernatant was repeated 5 times to remove the components dissolved in toluene. Some solids were collected and analyzed. Titanium was found in the solids.
It contained 1.9% by weight and 20.5% by weight of diisobutyl phthalate. This transition metal catalyst component slurry was used as it was, and 1 g of magnesium chloride was placed in an autoclave of 1, and 200 ml of toluene was added thereto, and the temperature was adjusted to 0 ° C .. In addition, 3 g of propylene was charged at 0 ° C., and polymerization was carried out for 2 hours while stirring.
When the obtained slurry was analyzed, 3 g of propylene was polymerized per magnesium chloride. Immediately after the polymerization, 0.19 g (1 mmol) of titanium tetrachloride was added, and the mixture was stirred for 3 hours.

Prepare an autoclave having an inner volume of 5 which was sufficiently dried and replaced with nitrogen, and 1.5 kg of propylene and 1.25 Nl of hydrogen were added thereto.
After heating to ℃, triethylaluminum in 100 ml of hexane
0.2 ml, cyclohexylmethyldimethoxysilane 0.04 m
(1) A slurry in which 10 mg of the above-mentioned transition metal catalyst component slurry treated with propylene was dispersed as magnesium chloride was injected under pressure, followed by polymerization at 70 ° C. for 2 hours.

After polymerization, unreacted propylene was purged, dried at 80 ° C. for 8 hours, and weighed to obtain 615 g of polypropylene. The intrinsic viscosity (hereinafter abbreviated as η) of the polypropylene measured at 135 ° C. in tetralin solution is 1.65 dl / g, and the boiling n-heptane extraction residue ratio (weight of polymer remaining after extraction / weight of polymer before extraction) measured with a Soxhlet extractor Was expressed as a percentage, hereinafter, abbreviated as II) was 99.0% and bulk specific gravity was 0.43 g / ml. The catalyst component slurry treated with propylene was
After storage at 48 ° C. for 48 hours, the same polymerization was carried out to obtain 605 g of a powder, η was 1.71 dl / g, II was 99.1%, and bulk specific gravity was 0.43 g / g.
ml.

Comparative Example 1 After treating with propylene, the procedure was the same as in Example 1, except that titanium tetrachloride was used without addition. The obtained polymer was 615 g, η was 1.68 dl / g, and II was 99.1%, which was good.
0 g, η was 1.72 dl / g and II was 98.9%. After 48 hours, the obtained polymer was 345 g, η was 1.69 dl / g, and II was 98.9%.

Comparative Example 2 The same procedure as in Example 1 was carried out except that the treatment with propylene was carried out without using alkoxysilicon, except that the amount of cyclohexylmethyldimethoxysilane used in the polymerization was 0.1 ml. As a result, 620 g of polypropylene was obtained. η is 1.58
dl / g and II were 98.3% and bulk specific gravity was 0.43 g / ml. The catalyst component slurry treated with propylene was stored at 10 ° C. for 48 hours, and then polymerized in the same manner to obtain 615 g of a powder.
1.60 dl / g, II was 98.2%, and bulk specific gravity was 0.43 g / ml.

Example 2 The procedure of Example 1 was repeated, except that diisobutyl phthalate was used instead of diisobutyl phthalate during co-milling to obtain 580 g of a polymer. Η was 1.71 dl / g, II was 98.9%, and bulk specific gravity was 0.43 g / ml. After storing the catalyst component slurry treated with propylene at 10 ° C. for 24 hours, the same polymerization was carried out to obtain 590 g of a powder, η was 1.68 dl / g, and II was 99.0.
%, Bulk specific gravity was 0.43 g / ml.

Comparative Example 3 The same procedure as in Example 2 was carried out except that cyclohexylmethyldimethoxysilane was not used in the treatment of propylene and titanium tetrachloride was not added, to obtain 595 g of a polymer.
1.66 dl / g, II was 99.0%, and bulk specific gravity was 0.43 g / ml. After storing the slurry treated with propylene at 10 ° C. for 24 hours, the same polymerization was performed to obtain 460 g of a polymer, and η was 1.
The activity was 71 dl / g, II was 98.9%, and the bulk specific gravity was 0.43 g / ml. The activity was significantly lower than that of Example 2.

Example 3 700 ml of refined kerosene, 10 g of magnesium chloride, 37 g of 2-ethylhexanol, and 3 g of phthalic anhydride were added to a round bottom flask having an internal volume of 2 and stirred at 100 ° C. for 24 hours to completely dissolve. Then, 10 ml of diisobutyl phthalate was added thereto, and the mixture was stirred. Then, the mixture was gradually dropped into titanium tetrachloride 2 kept at 0 ° C. in a round bottom flask of No. 5 with stirring. Thereafter, the temperature was slowly increased and the treatment was performed at 100 ° C. for 1 hour. Then only 200 solids
The mixture was transferred to a ml round bottom flask, 100 ml of titanium tetrachloride was further added, the mixture was stirred at 100 ° C., and finally, the solid content was washed 10 times with n-heptane to obtain a transition metal catalyst component.

Example 1 except that the transition metal catalyst component thus obtained was used.
Same as. However, the amount of titanium tetrachloride used was 0.2 mol times (0.15 g) per triethylaluminum. Immediately after propylene treatment, 620 g of polymer was obtained, η was 1.65 dl / g, II was
98.9%, bulk specific gravity is 0.46 g / ml, and after 48 hours polymer 61
0 g was obtained, η was 1.68 dl / g, II was 98.9%, and bulk specific gravity was 0.46 g / ml.

Comparative Example 4 The procedure of Example 3 was repeated except that cyclohexylmethyldimethoxysilane was not used in the treatment of propylene, and that titanium tetrachloride was not used. Immediately after propylene treatment, 600 g of polymer was obtained, η was 1.59 dl / g, II was 98.4%, and bulk specific gravity was 0.46 g / g.
After 48 hours, 370 g of a polymer was obtained, and η was 1.60 dl /
g and II were 98.3% and bulk specific gravity was 0.46 g / ml.

〔The invention's effect〕

By performing the method of the present invention, a high-performance transition metal catalyst component having no change over time can be obtained, which is industrially meaningful.

[Brief description of the drawings]

FIG. 1 is a flowchart for helping the understanding of the present invention.

Claims (1)

(57) [Claims] 1. A method of polymerizing propylene using a catalyst comprising a transition metal catalyst component in which a titanium compound is supported on a magnesium halide and an organoaluminum compound, wherein the transition metal catalyst component comprises magnesium halide and a diester of phthalic acid. Using a catalyst component containing a tetravalent titanium compound having at least one halogen, 0.1 to 100 g of propylene per magnesium halide in the catalyst component is polymerized in the presence of a trialkylaluminum compound and an alkoxysilicon compound. A method for polymerizing propylene, which comprises adding 0.05 to 10 times of titanium tetrahalide per trialkylaluminum used in polymerization.