JPH02202903A - Polymerization method of propylene - Google Patents

Abstract

PURPOSE:To polymerize propylene while preventing the aging of a catalyst by using a supported transition metal catalyst pretreated in a specified manner. CONSTITUTION:A process for polymerizing propylene in the presence of a catalyst composed of a transition metal catalyst comprising a titanium compound supported on a magnesium halide and an organoaluminum compound, wherein the catalyst used is one subjected to a pretreatment which comprises polymerizing propylene by using a catalyst containing a magnesium halide, a phthalic diester and a tetravalent titanium compound having at least one halogen atom, wherein propylene is used in an amount of 0.1-100g per g of the magnesium halide of the catalyst, in the presence of a trialkylaluminum compound and adding 0.05-10mol of a titanium tetrahalide per mol of the trialkylaluminum used in this reaction to the reaction mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for polymerizing propylene. More specifically, the present invention relates to a method in which a carrier-type transition metal catalyst is treated and used in a specific manner to eliminate changes in the catalyst over time.

[Prior art]

The method of polymerizing propylene using a catalyst comprising a transition metal compound supported on a carrier such as magnesium halide and an organometallic compound has undergone many improvements since it was disclosed in Japanese Patent Publication No. 39-12105. Improvements are mainly in the direction of what to use as the electron-donating compound to be used on the carrier side and the electron-donating compound to be used in combination of the transition metal catalyst and the organometallic compound, and further in the direction of how to produce the transition metal catalyst. This has been done in two ways. Among these methods, a method uses a bifunctional compound as an electron donating compound used on the carrier side, and an alkoxy silicon compound or a sterically hindered amine compound as the electron donating compound used in combination with a transition metal catalyst and an organometallic compound. is an excellent method for producing polypropylene with high activity and extremely high stereoregularity (for example, JP-A-58-138710, JP-A-59-1175).
09, 59-206407, 59-20841
0 etc.).

[Problem to be solved by the invention]

However, even with transition metal catalysts using the above-mentioned bifunctional compounds, there is a problem that when the catalyst is directly introduced into a polymerization tank set at a high temperature near the polymerization temperature, the activity and stereoregularity of the resulting polymer are insufficient. To solve this problem, a small amount of propylene is polymerized, but there is a problem with products treated in this way, especially when trialkyl almonium is used as the organoaluminum, which deteriorates over time and degrades performance. .

[Means to solve the problem]

The present inventors solved the above problems and completed the present invention by intensively studying a method of polymerizing polypropylene using a high-performance transition metal catalyst without changing over time.

That is, the present invention provides a method for polymerizing propylene using a transition metal catalyst in which a titanium compound is supported on magnesium halide and a catalyst consisting of an organoaluminum compound.
As a transition metal catalyst, a catalyst containing a magnesium halide, a diester of phthalic acid, and a tetravalent titanium compound having at least one halogen is used, and in the presence of a trialkylaluminium compound, 0.00% per magnesium halide in the catalyst is used. This method of polymerizing propylene is characterized in that 1 to 100 g of propylene is polymerized, and then titanium tetrahalide is added in an amount of 0.05 to 10 times the amount of trialkylaluminum used in the reaction.

In the present invention, as the magnesium halide, substantially anhydrous magnesium halide can be used, and several percent
Even those containing the following water can be used. Specifically, magnesium chloride, magnesium bromide, or a eutectic of magnesium chloride and magnesium bromide can be used.

As a diester of phthalic acid, phthalic acid and carbon number 1~
Esters with 12 alcohols are preferably used, such as dimethyl phthalate, diethyl phthalate, dipropyl phthalate, dibutyl phthalate, dioctyl phthalate, didecyl phthalate, diphenyl phthalate, dibenzyl phthalate, di-2-ethylhexyl phthalate, etc. In addition, diesters such as butylbenzyl phthalate and ethylhexyl phthalate, which have different alcohols forming two ester bonds, can also be used.

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

There are no particular restrictions on the method for producing a catalyst containing a diester of magnesium halide and phthalic acid and a tetravalent titanium compound having at least one halogen, and various known methods can be adopted. If necessary, a method of co-pulverizing other additives and then treating with titanium halide, a method of co-pulverizing the above three components and then treating with an aromatic hydrocarbon, or a method of co-pulverizing the above three components and then treating with an aromatic hydrocarbon, or a method of using magnesium halide in a hydrocarbon solvent with alcohol etc. After being dissolved, it is precipitated with titanium halide, etc.
It can be produced by a method of treating with a diester of phthalic acid during or after precipitation, and then treating with a titanium halide. Further, if necessary, inert inorganic compounds such as silica and alumina, or polymeric compounds such as polyethylene, polypropylene, and polystyrene may be used in combination.

In the present invention, the transition metal catalyst produced by the above method is then treated with 0.1 to 100 g of propylene per magnesium in the presence of a trialkylaluminium, which will be described below. In this case, the treatment temperature is preferably 40°C or lower; if the treatment is higher than 40°C, the stereoregularity of the polypropylene obtained will be poor, and the temperature is more preferably -70°C to 30°C. It is preferable that the amount of trialkylaluminum used is too large (usually 0.01 to 100 moles per titanium atom. 0.01
If the amount is less than twice the mole, polymerization will not occur even if propylene is introduced, which is preferable (Also, if too much organoaluminium is used, the activity of the resulting catalyst slurry will be severely reduced, more preferably about 0.1 to 30 moles) The amount of propylene polymerized is 0.00% per gram of magnesium halide.
It is preferable to introduce the catalyst into the polymerization system when it is about 1-100d; if it is less than 0.1g, the bulk specific gravity of the obtained polymer is unfavorable, and if it is more than 100g, it is difficult to introduce the catalyst into the polymerization system. 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, ethylbenzene, etc. The concentration of the transition metal catalyst at that time is preferably about 0.1 to 100 g/l of magnesium halide, taking into consideration the concentration used thereafter.

In the present invention, trialkylaluminum is used to treat a small amount of propylene, but trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminium, etc. is also preferably used as an organoaluminum compound used in the subsequent polymerization described below. is used.

In the present invention, titanium tetrahalide is added to the slurry treated with propylene.

The amount of Wf5 is 0.05 to 10 moles, more preferably 0.1 to 2 moles, of the trialkylaluminium used in the treatment of a small amount of propylene. 0.0
If it is less than 5 mol, it will not be effective in reducing the change in slurry over time (and if it is too large, it will not be more effective.

In the present invention, the transition metal catalyst slurry thus obtained is then further added with an organoaluminum and used for the actual polymerization at a higher temperature. Against 10
~10,000 times the amount of organic aluminum is used.

The organoaluminum can also be introduced into the polymerization system separately from the propylene-treated catalyst slurry.

In the present invention, during polymerization, it is preferable to use an alkoxysilane or a substituted piperidine as a stereoregularity improver. As the alkoxysilane, an organic silane compound containing 1 to 4 alkoxy groups is preferably used,
Examples of the alkoxy group include those having a structure in which oxygen is bonded to an alkyl group or alkenyl group having 1 to 12 carbon atoms, and examples of the remaining groups include alkyl groups having 1 to 12 carbon atoms or alkenyl groups. In addition, as substituted piperidine,
Some or all of the hydrogens at the 1st and 6th positions have 1 to 12 carbon atoms.
Preferred examples include compounds substituted with an alkyl group or an alkenyl group. This stereoregularity improver can be added not only during the original polymerization but also during the initial polymerization of a small amount of propylene, and in some cases can provide polypropylene with higher stereoregularity.

The ratio of organoaluminium to stereoregularity improver is usually about 1 to 1 to 1 to 10.

In the present invention, the polymerization method for the original propylene polymerization is not particularly limited, and various known methods can be adopted.
Any of the following methods can be employed: solvent polymerization using an inert hydrocarbon as a medium, bulk polymerization using liquid propylene as a medium, and gas phase polymerization using substantially no liquid medium.
During polymerization, the temperature was higher than the temperature for processing the small amount of propylene mentioned above, at ~150°C, and the pressure was at normal pressure ~100 kg/
This polymerization method is generally carried out using cffl, and in addition to homopolymerization of propylene, this polymerization method can be preferably employed for random copolymerization or block copolymerization with other olefins such as ethylene, butene, pentene, and hexene.

〔Example〕

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

Example 1 A vibratory mill equipped with four grinding pots each having an internal volume of 4N each containing 9 kg of steel balls with a diameter of 12 mm was prepared. Add 300 g of magnesium chloride and 60 layers of 115-1 titanium tetrachloride of diisobutyl phthalate to each pot in a nitrogen atmosphere.
Time crushed. The co-pulverized product Log was placed in a 200 d flask, 40 ml of toluene was added thereto, heated to boiling of toluene, and stirred for 30 minutes. Next, the supernatant was removed at 100°C, 100 id of toluene was added, the mixture was stirred at 100°C, and then left to stand, and the supernatant was removed. This procedure was repeated five times to remove the components dissolved in toluene. When a part of the solid content was collected and analyzed, it was found that the solid content contained 1.9 wt x of titanium and 20.5 wt $ of diisobutyl phthalate. Using this transition metal catalyst slurry as it was, 1 g of magnesium chloride was placed in a 12 autoclave, 200°C of toluene was added, the temperature was raised to 0°C, and 0.5% of triethylaluminum was added. d (4 mmol) was added, and 3 g of propylene was charged at 0° C., and polymerization was carried out for 2 hours while stirring. Analysis of the resulting slurry revealed that 3 g of propylene was polymerized per magnesium chloride. Immediately after the polymerization, 0919 g (1 mmol) of titanium tetrachloride was added and stirred.

Prepare a sufficiently dried autoclave with an internal volume of 51 cm and purged with nitrogen, and add 1.5 kg of propylene and 1.25 Nj of hydrogen.
! was added and the temperature was raised to 60°C, and then the transition metal catalyst slurry treated with hexane, 1 ooai nitriethylaluminum O, ld, cyclohexylmethyldimethoxysilane 0.05 m, and the above propylene was converted into magnesium chloride and 10
A slurry in which 100 mg of fluorine was dispersed was added under pressure and polymerized at 70° C. for 2 hours.

After the polymerization, unreacted propylene was purged and the mixture was dried at 80° C. for 8 hours and weighed to obtain 630 g of polypropylene. In addition, the intrinsic viscosity (hereinafter abbreviated as η) of polypropylene measured with a 135°C tetraone solution is 1.58, and the boiling n-heptane extraction residue measured with a Soxhlet extractor (weight of extracted polymer/weight of extracted residual polymer is 100 Expressed as a fraction (hereinafter abbreviated as If) is 98.3χ, bulk specific gravity 0
．． It was 43g/ad. This propylene-treated catalyst slurry was stored at 10''C for 48 hours and then similarly polymerized to obtain 635g of powder, with a η height of 60.
II was 98.3% and bulk specific gravity was 0.43 g/ag.

Comparative Example 1.2 Polymerization was carried out using the slurry that had been heated with toluene and washed without treatment with propylene. 610 g of polymer was obtained, η was 1.60, and I
I was 95.6χ and bulk specific gravity was only 0.36 g/d (Comparative Example 1). In addition, by reducing the amount of propylene introduced in the treatment with propylene, o, os per magnesium chloride can be obtained.
g, 620g of polymer was obtained, and η was 1.59.
,! In case (2), the bulk specific gravity was 96.0χ and only 0.37 g/d (Comparative Example 2).

Comparative Example 3 The same procedure as Example 1 was carried out except that titanium tetrachloride was used as it was without adding titanium tetrachloride after treatment with propylene. The obtained polymer was 635 g, η was 1.58, and II was 98.
It was good at 2X, but when used after 24 hours, the obtained polymer was 480g, and ηha1.58.11 was 98.0!
After 48 hours, the obtained polymer was 360 g, η was 1.55, and the activity of (1) was 98.0χ, which significantly decreased the activity.

Example 2 During co-pulverization, di-isobutyl phthalate was used instead of di-isobutyl phthalate.
The same procedure as in Example 1 was carried out except that n-butyl was used, and 590 g of polymer was obtained. Also, η is 1.55! ■ is 98.
2χ, bulk specific gravity 0.42g/! I! It was l. After storing this propylene-treated catalyst slurry at 10°C for 24 hours, it was similarly polymerized to obtain 585g of powder.
η is 1.58, II is 98.4χ, bulk specific gravity is 0.43g
/m1.

Comparative Example 4 The same procedure as Example 2 was carried out except that titanium tetrachloride was not added, and 580 g of polymer was obtained, η was 1.57, II was 98.4χ, and the bulk specific gravity was 0.43 g/-. Ta. In addition, when the slurry treated with propylene was stored at 10°C for 24 hours and polymerized in the same manner, 470g of polymer was obtained.
obtained, I is 1.58, II is 98.4χ, bulk specific gravity is 0.4
3 g/d, and the activity was significantly lower than that of Example 2.

Example 3 In a round bottom flask with an internal volume of 21, 10 g of refined kerosene 700-1 magnesium chloride and 37 g of 2-ethylhexanol,
3 g of phthalic anhydride was added and stirred at 100°C for 24 hours to completely dissolve. After adding 10-diisobutyl phthalate to the mixture and stirring, the mixture was heated to 0°C in a 51 round bottom flask.
The mixture was added dropwise to titanium tetrachloride 21, which was maintained at a temperature of 100.degree. C., under stirring.

Thereafter, the temperature was slowly raised to 100° C. for 1 hour. Next, only the solid content was transferred to a 200-mm round bottom flask, and further 1001 d of titanium tetrachloride was added, and the mixture was stirred at 100°C.Finally, the solid content was washed 10 times with 1 helibutane to obtain a transition metal catalyst. .

The same procedure as in Example 1 was carried out except that the transition metal catalyst thus obtained was used. However, the amount of titanium tetrachloride used was 0.2 mole times (0.15 g) per triethylaluminum. Immediately after propylene treatment, 604 g of polymer was obtained, and η was 1.60.
, II is 98.3χ, bulk specific gravity is o,,i6g/d, 598g of polymer was obtained after 48 hours, η is 1.58, ■!
is 98.4m, bulk specific gravity is 0.46g/sdi? there were.

Comparative Example 5 The same procedure as Example 3 was carried out except that titanium tetrachloride was not used. Immediately after propylene treatment, 594 g of polymer was obtained, 77
Ha1.60. II is 98.4X, bulk specific gravity is 0.46
g/d, but after 48 hours, 386 g of polymer was obtained, η
is 1.59, +1 is 98.3X, bulk specific gravity is 0.46g
/adl Thea, Ri.

〔Effect of the invention〕

By implementing the method of the present invention, a high-performance transition metal catalyst that does not change over time can be obtained, which is industrially significant.

[Brief explanation of the drawing]

FIG. 1 is a flowchart diagram to aid understanding of the present invention. Patent applicant Mitsui Toatsu Chemical Co., Ltd.

Claims (1)

[Claims] 1. In a method of polymerizing propylene using a catalyst consisting of a transition metal catalyst in which a titanium compound is supported on magnesium halide and an organoaluminium compound, magnesium halide, a diester of phthalic acid, and at least one halogen are used as the transition metal catalyst. 0.1 to 100 g of propylene is polymerized per magnesium halide in the catalyst in the presence of a trialkylaluminium compound using a catalyst containing a tetravalent titanium compound having 0.0
A method for polymerizing propylene, characterized in that 5 to 10 times as much titanium tetrahalide is added.