JPH07651B2 - Method for producing olefin polymer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an olefin polymer. More specifically, the present invention provides the production of an olefin polymer capable of obtaining a high stereoregular polymer in a high yield when applied to the polymerization of α-olefin having 3 or more carbon atoms by using a specific catalyst. Concerning the law.

So far, a catalyst system comprising a solid catalyst component in which a titanium compound is supported on magnesium halide and an organoaluminum compound has higher polymerization activity than conventional catalyst systems,
It has been said that there may be no need to remove catalyst residues from the polymer.

However, since the supported catalyst has low stereoregularity,
Although it has been considered impossible to omit the extraction step, in recent years, the stereoregularity has been considerably improved by improving the cocatalyst system.
Esters as polymerization additives (JP-B-56-39767, JP-A-58-157808, etc.) and phenyl- or alkyl-group-containing silic group compounds (JP-A-57-63310 and JP-A-57-63310)
57-63311, etc.), it is known that high activity and high stereoregularity polymerization can be achieved to some extent. However, it is difficult to realize a detouching-free and extraction-free process even with these proposed polymerization additives, and further improvement has been desired.

SUMMARY OF THE INVENTION Accordingly, the present inventors have eagerly searched for a highly active and highly stereoregular polymerization additive capable of realizing a detouching-free and extraction-free process. As a result, surprisingly, the present invention was achieved by using a silicon compound containing a cycloaliphatic hydrocarbon group to realize highly active and highly stereoregular polymerization.

That is, the method for producing an olefin polymer according to the present invention is
In a method for producing an olefin polymer by stereoregularly polymerizing olefins in the presence of a catalyst, the catalyst comprises a solid catalyst component (A) containing magnesium halide and titanium halide as essential components, and (B) an organoaluminum. Compound and (C) formula R ¹ R ² Si (OR ³ ) ₂ or R ¹ Si (OR ³ ) ₃
A catalyst comprising an organosilicon compound represented by the formula (wherein R ¹ is a cycloaliphatic hydrocarbon group having 5 to 12 carbon atoms, and R ² is 1 to 12 carbon atoms. It is a cyclic or chain-like aliphatic hydrocarbon group, and R ³ has 4 carbon atoms.
The following is a chain aliphatic hydrocarbon group).

Effect According to the catalyst of the present invention, polyolefin can be obtained in high yield and with high stereoregularity.

DETAILED DESCRIPTION OF THE INVENTION Catalyst The catalyst according to the present invention comprises three specific components, (A), (B) and (C).

Solid catalyst component (A) The solid catalyst component (A) used in the present invention contains magnesium halide and titanium halide as essential components.

As magnesium halide, magnesium chloride,
Magnesium bromide and magnesium iodide can be used. Magnesium chloride is preferable, and it is desirable that it is substantially anhydrous.

As the titanium halide, titanium chloride, bromide and iodide can be used. Chlorides are preferable, and titanium tetrachloride and titanium trichloride can be exemplified, but titanium tetrachloride is particularly preferable. Further, an alkoxy group-containing titanium compound represented by the general formula Ti (OR) _n Cl _4-n (R is an alkyl group) can also be used.

In preparing the solid catalyst component of the present invention, various electron donors may be added, or are preferable. Examples of the electron donor include oxygen-containing compounds and nitrogen-containing compounds.

As the oxygen-containing compound, ether, ketone and ester can be used, but ester is preferably used.

As the ester, a carboxylic acid ester is mainly used, and examples of the aliphatic carboxylic acid ester include ethyl acetate, methyl acetate cellosolve, ethyl acetate cellosolve, methyl methacrylate, diethyl oxalate, dibutyl maleate and the like. Examples of the aromatic carboxylic acid ester include ethyl benzoate, methyl p-toluate, diethyl phthalate, diheptyl phthalate and the like. Particularly preferred among these esters are
Phthalates such as diethyl phthalate and diheptyl phthalate.

In preparing the solid catalyst component, it is desirable to first perform a pretreatment of magnesium chloride. This can be carried out using a technique of pulverization or dissolution / precipitation. Grinding of magnesium chloride can be carried out using a ball mill or a vibration mill. Dissolution of magnesium chloride can be carried out by using hydrocarbon or halogenated hydrocarbon as a solvent and alcohol, phosphate ester, titanium alkoxide or the like as a dissolution accelerator. Precipitation of the dissolved magnesium chloride can be carried out by adding a poor solvent, an inorganic halide, an electron donor such as an ester, or methylhydrogenpolysiloxane. Details of such a pretreatment for activation of magnesium chloride can be found in the patent publication
53-45688, 54-31092, 57-180612, 58-5309
No. 58-5310 and No. 58-5310.

The contact between the pretreated magnesium chloride, the titanium halide and the electron donor may also be achieved by forming a complex of the titanium halide and the electron donor and then contacting the complex with magnesium chloride, Either contacting magnesium chloride with titanium halide and then contacting with an electron donor or contacting magnesium chloride with an electron donor and then contacting with titanium halide may be performed.

As the contact method, crushing contact such as a ball mill or a vibration mill may be used, or magnesium chloride or a product treated with an electron donor of magnesium chloride may be added to the liquid phase of titanium halide.

The washing with an inert solvent may be carried out after the contact with the three or four components or at an intermediate stage between the contact with the respective components.

The solid catalyst component thus produced has a titanium halide content of 1 to 20% by weight, and the molar ratio of the electron donor to the titanium halide is about 0.05 to 2.0.

Organoaluminum Compound (B) As the organoaluminum compound (B) used in the present invention, trialkylaluminum is preferable. Examples of the trialkyl aluminum include trimethyl aluminum, triethyl aluminum, tri i-butyl aluminum, tri n-hexyl aluminum, and the like. Particularly preferred is triethylaluminum. Further, an organic aluminum compound such as an alkylaluminum halide or an alkylaluminum alkoxide can be used together.

Organoaluminum compound (B) used in polymerization
And the molar ratio of titanium halide in the solid catalyst (A) is
A range of 10 to 1000 is usually used.

Organosilicon compound (C) The component (C) used in the present invention has the general formula R ¹ R ² Si (OR ³ ) ₂
Alternatively, it is an organosilicon compound represented by R ¹ Si (OR ³ ) ₃ . In the formula, R ¹ is a cyclic aliphatic hydrocarbon group having 5 to 12 carbon atoms, R ² is a cyclic or chain aliphatic hydrocarbon group having 1 to 12 carbon atoms, and R ³ is 4 or less carbon atoms. It is a chain aliphatic hydrocarbon group. The following are specific examples of the compound (C) represented by structural formulas.

The molar ratio of the organosilicon compound and the organoaluminum compound used is usually 0.01 to 1.0, preferably 0.02 to 0.5,
It is a degree.

Polymerization Polymerization of olefins using the catalyst system of the present invention is suitably carried out in homopolymerization of ethylene, propylene, and butene or in copolymerization in which these monomers are combined.

The polymerization can be carried out in the presence of an inert solvent, or in the absence thereof, that is, in a gas- or liquid-phase bulk polymerization.
The polymerization mode may be continuous or batch. The molecular weight of the polymer can be adjusted by controlling the hydrogen concentration in the polymerization vessel. The polymerization temperature is 0 to 200 ° C, preferably 50 to 100 ° C,
The range of is selected. The polymerization pressure is usually in the range of 1 to 100 atm.

Experimental Example Example 1 (1) Preparation of solid catalyst component A glass three-necked flask (with a thermometer and a stir bar) having an inner volume of 500 ml replaced with nitrogen was charged with 75 ml of purified heptane and 75 ml.
Titanium tetrabutoxide, 10 g of anhydrous magnesium chloride are added. Then, the flask is heated to 90 ° C., and the temperature is changed for 2 hours to completely dissolve magnesium chloride. Next, the flask is cooled to 40 ° C., and 15 ml of methylhydrogen polysiloxane is added to precipitate a magnesium chloride / titanium tetrabutoxide complex. After washing this with purified heptane, 8.7 ml of silicon tetrachloride and 1.8 ml of diheptyl phthalate are added, and the mixture is kept at 50 ° C. for 2 hours. After this, wash with purified heptane and add 25 ml of titanium tetrachloride.
And hold at 90 ° C for 2 hours. This was washed with purified heptane to obtain a solid catalyst component.

The titanium content in the solid catalyst component was 3.0% by weight, and the diheptyl phthalate content was 25.0% by weight.

(2) Polymerization A stainless steel autoclave with an internal volume of 3 liters was purged with nitrogen, purified heptane 1.5 liters, triethylaluminum (B) 0.75 g, 2-norbornylmethyldimethoxysilane (C) 0.13 g and the above solid catalyst components ( A) 50m
Charge g and hydrogen in an amount corresponding to a partial pressure of 0.15 kg / cm ² . Then, after raising the temperature of the autoclave to 70 ° C., the pressure of propylene was raised to 7 kg / cm ² G to start the polymerization, and the polymerization was continued for 3 hours while supplying propylene so as to maintain this pressure.

After 3 hours, the introduction of the monomer was stopped and the unreacted monomer was purged to terminate the polymerization.

The resulting polymer was separated from heptane and dried to give 78
3.1 g of polypropylene powder was obtained. When heptane was removed from the solution by heating, 2.2 g of an amorphous polymer was obtained. The proportion of the amorphous polymer in all the polymers (hereinafter referred to as APP by-product rate) was 0.28%.

The boiling n-heptane insoluble content (hereinafter referred to as P-II) of polypropylene powder was 98.3%. The polymer yield per solid catalyst (hereinafter referred to as CY) was 15706. The MFR (melt flow index: measured according to ASTM-D-1238) was 1.86 and the bulk specific gravity was 0.46.

Comparative Example 1 A solid catalyst component was prepared in the same manner as in Example 1, and was polymerized in the same manner as in Example 1 except that 0.08 g of dimethyldimethoxysilane was used as the polymerization additive (C).

As a result, 352.1 g of polypropylene powder was obtained,
The by-product rate was 6.31%. 85.4% for P-II, 7515 for CY, MF
The R was 11.31 and the bulk specific gravity was 0.35.

Comparative Example 2 A solid catalyst component was prepared in the same manner as in Example 1, and was polymerized in the same manner as in Example 1 except that 0.14 g of n-hexyltrimethoxysilane was used as a polymerization additive (C).

As a result, 416.8 g of polypropylene powder was obtained.
The by-product rate was 1.43%. P-II is 96.3%, CY is 8454, MF
The R was 5.52 and the bulk specific gravity was 0.44.

Example 2 A solid catalyst component was prepared in the same manner as in Example 1 and used as a polymerization additive (C) 2-norbornylmethyldimethoxysilane.
Polymerization was performed in the same manner as in Example 1 except that 26 g was used.

As a result, 816.4 g of polypropylene powder was obtained.
The by-product rate was 0.26%. P-II is 98.8%, CY is 16372, M
The FR was 1.61 and the bulk specific gravity was 0.46.

Example 3 A solid catalyst component was prepared in the same manner as in Example 1, and 0.17 g of 2-norbornyltriethoxysilane was used as a polymerization additive (C).
Polymerization was performed in the same manner as in Example 1 except that

As a result, 623.1 g of polypropylene powder was obtained.
The by-product rate was 0.25%. 98.9% for P-II, 12493 for CY, M
The FR was 1.87 and the bulk specific gravity was 0.46.

Example 4 Preparation of solid catalyst component A glass three-necked flask (with a thermometer and a stir bar) having an inner volume of 500 ml and purged with nitrogen was charged with 75 ml of purified heptane and 75 ml.
Of titanium tetrabutoxide and 10 g of anhydrous magnesium chloride are added. Then heat the flask to 90 ° C and
Dissolve the magnesium chloride completely over time. Next, the flask is cooled to 40 ° C., and 15 ml of methylhydrogen polysiloxane is added to precipitate a magnesium chloride / titanium tetrabutoxide complex. After washing with purified heptane, 8.7 ml of silicon tetrachloride and 1.5 ml of phthaloyl chloride are added, and the mixture is kept at 50 ° C. for 2 hours. After this, wash with purified heptane and add 25 ml of titanium tetrachloride.
And hold at 30 ° C. for 2 hours. This was washed with purified heptane to obtain a solid catalyst component.

The titanium content in the solid catalyst component was 3.3% by weight, and the specific surface area of the solid catalyst component was 1.2 m ² / g.

Polymerization Polymerization was carried out in the same manner as in Example 1. As a result, 832.7 g of polypropylene powder was obtained, and the APP byproduct rate was 0.28%. P-II is 98.3%, CY is 16701, MFR is 1.73, and bulk specific gravity is
It was 0.46.

Examples 5 to 7 and Comparative Examples 3 to 4 Solid catalyst components were prepared in the same manner as in Example 1 and were polymerized in the same manner as in Example 1 except that the compounds shown in Table 1 were used as the polymerization additive (C). I did. The results are shown in Table 1.

Example 8 (1) Preparation of solid catalyst component 85.8 g of anhydrous magnesium chloride, 17.4 g of diisobutyl phthalate, and 13.9 g of vinyltriethoxysilane were co-ground in a vibration mill for 60 hours. 25 g of the co-ground product was transferred to a 500 ml flask in a nitrogen atmosphere, 210 ml of titanium tetrachloride was added, and the mixture was stirred at 80 ° C. for 2 hours. Then, the solid catalyst component was obtained by washing with purified heptane. Titanium content in the solid catalyst is 2.4% by weight, diisobutyl phthalate content is 17.3% by weight
Met.

(2) Polymerization The same procedure as in Example 1 was carried out. CY is 14,805, APP byproduct rate is
0.29%, P-II was 98.1%, MFR was 1.93 g / 10 minutes, and the bulk specific gravity of the powder was 0.45 g / cm ³ .

Example 9 (1) Preparation of solid catalyst component 20 g of magnesium chloride, 4 ml of tetraethoxysilane, α,
3 ml of α, α-trichlorotoluene was co-ground with a vibration mill for 48 hours. 40 g of this co-ground product was placed in a 1-liter flask, 300 ml of titanium tetrachloride was added, and the mixture was stirred at 80 ° C. for 2 hours, then the supernatant was removed and washed with purified heptane to obtain a solid catalyst component. The titanium content in the solid catalyst was 1.9% by weight.

(2) Polymerization The same procedure as in Example 1 was carried out. CY is 17,836, APP byproduct rate is
0.85%, P-II 96.8%, MFR 2.35 g / 10 minutes, and the bulk specific gravity of the powder was 0.45 g / cm ³ .

Example 10 (1) Preparation of solid catalyst component Anhydrous magnesium chloride (4.76 g), decane (25 ml) and 2-ethylhexyl alcohol (23.4 ml) were heated at 130 ° C. for 2 hours to form a uniform solution, and phthalic anhydride was added to the solution.
1.11 g was added, and the mixture was further stirred and mixed at 130 ° C. for 1 hour to dissolve phthalic anhydride in the homogeneous solution. The homogeneous solution thus obtained is cooled to room temperature and then added dropwise to 200 ml of titanium tetrachloride kept at -20 ° C over 1 hour.
Then, the temperature of this mixed solution was raised to 110 ° C. over 4 hours, and when it reached 110 ° C., diisobutyl phthalate 2.68 m
1 (12.5 mmol) is added, and the mixture is kept under stirring at the same temperature for 2 hours. After the completion of the reaction for 2 hours, a solid part was collected by hot filtration, and the solid part was resuspended in 200 ml of titanium tetrachloride, and then heated again at 110 ° C. for 2 hours.
After completion of the reaction, the solid part was collected again by hot filtration and washed with decane and hexane at 110 ° C. to obtain a solid catalyst component. The titanium content in the solid catalyst component was 3.1% by weight, and the diisobutyl phthalate content was 20.9% by weight.

(2) Polymerization The same procedure as in Example 1 was carried out. CY is 16,983, APP byproduct rate is
0.35%, P-II was 97.9%, MFR was 1.91 g / 10 minutes, and the bulk specific gravity of the powder was 0.46 g / cm ³ .

Examples 11 to 13 and Comparative Examples 5 to 7 Solid catalyst components were prepared in the same manner as in Example 1, and the compounds listed in Table 2 were used as the organoaluminum compound (B) and the polymerization additive (C) used during polymerization. Polymerization was performed in the same manner as in Example 1 except that it was used. The results are shown in Table 2.

[Brief description of drawings]

FIG. 1 is intended to help the understanding of the technical content of the present invention regarding the Ziegler catalyst.

Claims (1)

[Claims] 1. A method for producing an olefin polymer by stereoregularly polymerizing an olefin in the presence of a catalyst,
The catalyst is (A) a solid catalyst component containing magnesium halide and titanium halide as essential components, (B) an organoaluminum compound, and (C) a formula R ¹ R ² Si (OR ³ ) ₂ or R ¹
Si (OR ³ ) ₃ characterized by being a catalyst composed of an organosilicon compound, a method for producing an olefin polymer (wherein R ¹ is a cycloaliphatic hydrocarbon group having 5 to 12 carbon atoms, R ²
Is a cyclic or chain-like aliphatic hydrocarbon group having 1 to 12 carbon atoms, and R ³ is a chain-like aliphatic hydrocarbon group having 4 or less carbon atoms).