JPS591405B2 - α-olefin polymerization method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for polymerizing highly stereoregular poly-α-olefins using a highly active catalyst system consisting of a special activated titanium component and an organoaluminium compound. .

It is known to polymerize α-olefins such as propylene and butene to stereoregular polyα-olefins using a so-called Cheedler or Natsuta catalyst consisting of titanium chloride and an organoaluminum compound, and this is not currently being carried out industrially. There is.

In recent years, a method has been developed to increase the activity of the catalyst by supporting the titanium component of Ziegler and Natsuta catalysts on a carrier, and this is becoming common for ethylene polymerization catalysts, but for α-olefins such as propylene, butene, etc. Useful crystalline polymers cannot be obtained unless alkyl groups such as methyl and ethyl groups are sterically controlled to form an isotactic structure. However, controlling the stereoregularity of the resulting polymer is a major problem.

In connection with this, there is a method of improving the stereoregularity of the produced polymer by adding an electron donor compound as a third component to a carrier-type titanium component in which a titanium compound is supported on magnesium halide and an organoaluminum compound. It has been proposed in JP-A-47-9342, JP-A-48-16980, JP-A-49-86482, etc. When propylene is polymerized using a two-component catalyst consisting of a supported titanium component and an organoaluminum compound, the polymerization activity is high, but the crystallinity of the resulting polymer is extremely low.Addition of an electron donor compound improves the crystallinity of the resulting polymer, but The activity is severely reduced, and the crystallinity improvement effect is not sufficient, and the quality is equivalent to that of the crystalline polypropylene obtained with the titanium trichloride/diethyl aluminum monochloride catalyst system currently used industrially. It was difficult to obtain.

The method of JP-A-50-126590 proposes a catalyst system consisting of a composition obtained by co-pulverizing magnesium halide and an organic acid ester and reacting titanium tetrachloride with an organoaluminum compound. Even with this, the crystallinity of the active and produced polymers is insufficient and needs improvement.

The present inventor investigated highly active catalysts that can polymerize highly crystalline polyα-olefins and found that (4) magnesium halide and aluminum halide. It has been discovered that a catalyst system obtained from an activated titanium component obtained by reacting a composition comprising an organic acid ester complex with titanium tetrachloride and (B) an organoaluminum compound is extremely effective.

The magnesium halide used in the method of the present invention is preferably a substantially anhydrous magnesium halide, and particularly preferably magnesium chloride.

Aluminum halide. As the aluminum halide used for preparing the organic acid ester complex, aluminum trichloride and aluminum tribromide are particularly preferred. As organic acid esters, aromatic carboxylic esters, aliphatic carboxylic esters, and alicyclic carboxylic esters are used, such as methyl benzoate, ethyl benzoate, propyl benzoate, phenyl benzoate, ethyl anisate, and ethyl naphthoate. , ethyl acetate, ethyl acrylate, ethyl methacrylate, ethyl hexahydrobenzoate, and the like. The complex of aluminum halide and organic acid ester can be prepared by a conventional method, for example, by mixing the two at room temperature or heating the mixture. The method for preparing the activated titanium component (4) of the present invention will be explained below.

First, magnesium halide and aluminum halide. A composition comprising an organic acid ester complex is prepared. A common method for preparing this is to grind both, for example, using a ball mill. This is done using a crusher such as a vibrating mill.

The grinding operation must be carried out in a vacuum or in an inert gas atmosphere, with water, etc. being almost completely removed. There are no particular restrictions on the crushing conditions (the temperature is generally in the range of 0°C to 50°C, and the crushing time varies depending on the type of crusher, but is usually 2 to 1
00 hours. Magnesium halide and aluminum halide. The composition with the organic acid ester complex is then treated with titanium tetrachloride.

This treatment is applied to the above magnesium halide. After suspending the organic acid ester complex composition in a solution of titanium tetrachloride or its inert solvent and contacting it at a temperature of 40°C to 135°C, the solid substance is separated and dried or treated with an inert solvent. It consists of an operation in which titanium tetrachloride is removed by washing to obtain an activated titanium component, which is component (4) of the present invention.

In the method of the present invention, a highly active α
-Olefin polymerization catalyst.

The organoaluminum compound used has the general formula At
Rm
triethylaluminum, tri-n-butylaluminum, tri-1s0-butylaluminum, tri-n
-Hexylaluminum diethylaluminum hydride, diethylaluminum ethoxide, etc. are used. In the method of the present invention, in addition to the activated titanium component and the organic aluminum compound, a known third component, such as the above-mentioned organic acid esters, may be added. In the method of the present invention, the ratio of the activated titanium component to the organoaluminum compound used can be varied over a wide range, but generally the molar ratio of the organoaluminum compound to the titanium metal in the activated titanium component is about 1 to 500, especially when forming The number is preferably 2 to 25 in order to improve the crystallinity of the polymer. Further, when adding a third component such as an organic acid ester during polymerization, it is preferable to increase this molar ratio to 25 to 100. The method of the present invention involves the homopolymerization of α-olefins represented by the general formula R-C℃H2 (wherein R represents an alkyl group having 1 to 10 carbon atoms), and the copolymerization of the α-olefins with each other or with ethylene. Used for copolymerization.

The above α-olefins include propylene, butene-1
, hexene-1,4-methylbenzene-1, and the like.

For the polymerization reaction according to the method of the present invention, conventional methods and conditions commonly used in the art can be employed.

The polymerization temperature at that time is 20 to 300°C, preferably 50 to 300°C.
The temperature is 200°C, and the polymerization pressure is in the range of normal pressure to 200 atm, preferably in the range of normal pressure to 150 atm. In general, aliphatic, cycloaliphatic, aromatic hydrocarbons, or mixtures thereof, can be used as solvents in polymerization reactions, such as propane, butane, pentane, hexane, heptane,
Cyclohexane, benzene, toluene, etc., and mixtures thereof are preferably used. It is also possible to perform bulk polymerization using the liquid monomer itself as a solvent. Furthermore, it can also be carried out under conditions in which a solvent is substantially absent, that is, by a so-called gas phase polymerization method in which a gaseous monomer and a catalyst are brought into contact. The molecular weight of the polymer produced in the method of the present invention varies depending on the reaction mode, catalyst system, and polymerization conditions.
It can be controlled by adding alkyl halides, dialkyl zinc, etc.

Examples of the present invention are shown below.

Example 1 A vibratory mill equipped with a crushing pot having an internal volume of 600 d and containing 80 steel balls with a diameter of 12 mm was prepared.

In this pot, in a nitrogen atmosphere, add 20 mg of magnesium chloride.
．． 0V1 aluminum chloride. Ethyl benzoate complex 10.
07 was added and the mixture was ground for 20 hours. In a 300m1 round bottom flask, the above pulverization treatment 107 and titanium tetrachloride 200ffL1
After stirring at 80°C for 2 hours, the supernatant was removed by decantation, and then 200°C of n-heptane was added.
After adding m1 and stirring at room temperature for 30 minutes, the washing operation of removing the supernatant liquid by decantation was repeated seven times, and then 200 m1 of n-heptane was further added to obtain an activated titanium component slurry.

When a part of this activated titanium component slurry was sampled, n-heptane was evaporated, and analyzed, it was found that the activated titanium component contained 1.20 wt% Ti. Inner volume: 2 tons (7) In an autoclave made of SUs-32, n-heptane: 1 ton: 1 ton of the above activated titanium component: 0.2
07 (0.05mM in terms of titanium atoms) and 0.07ml (0.5mM) of triethylaluminum were charged.

After exhausting the nitrogen in the autoclave with a vacuum pump,
Charge hydrogen at a gas phase partial pressure of 0.3 kg/Crill, then charge propylene to reduce the pressure in the gas phase to 2 kg/C7iL.
I used it as a gauge. The contents of the autoclave were heated, and the internal temperature was raised to 70° C. after 5 minutes, and polymerization was continued for 2 hours while charging propylene to maintain the polymerization pressure at 70° C. at 5 kg/CTii gauge. After cooling the autoclave, unreacted propylene was purged, the contents were taken out, and the autoclave was dried under reduced pressure at 6'C to obtain white powdery polypropylene 3707.

The proportion of the residual polymer after boiling n-heptane extraction of this polypropylene (hereinafter abbreviated as powder 11) is 96.5%,
The bulk specific gravity was 0.337/Wlll intrinsic viscosity number was 1.90.

On the other hand, by concentrating oral fluid, n-heptane soluble polymer 17
V is obtained.

The ratio of the boiling n-heptane extraction residual polymer to the total polymer (hereinafter abbreviated as total 11) was 92.2%.
The polymerization activity of the catalyst in this polymerization reaction was 81k9/7-Ti.
hr, and the amount obtained was 161k9/7-Ti.

Example 2 The activated titanium component prepared in Example 1 was used to carry out bulk polymerization of propylene.

Internal volume 6t (7) 0.20y1 activated titanium component suspended in 30ml n-heptane in a nitrogen atmosphere in a Sus-32 autoclave 0.1ml triethylaluminum
was loaded.

After exhausting the nitrogen in the autoclave with a vacuum pump,
2.5 kg of propylene and 0.5 Nt of hydrogen were charged into the autoclave. Heat the contents of the autoclave,
After 5 minutes, the temperature was raised to 75°C, and polymerization was carried out at 75°C for 3 hours. After cooling the autoclave, the propylene was purged and the contents were taken out and dried under reduced pressure.908'! Polypropylene powder No. 7 was obtained. The resulting polypropylene powder had a total weight of 93.5%, an intrinsic viscosity of 1.95, and a bulk specific gravity of 0.38 V/ml.

The polymerization activity of the catalyst in this polymerization reaction is 126 kg/y-Ti
．． hr, and the amount obtained was 378 kg/7-Ti.

Example 3 The same experiment as in Example 2 was repeated using 0.15 ml of tri-1s0-butylaluminum instead of triethylaluminum to obtain 880y polypropylene powder.

The total weight of the obtained polypropylene 11 was 93.0%, the bulk specific gravity was 0.36 t/Mll, and the intrinsic viscosity was 1.95.

The polymerization activity in this polymerization reaction was 122 kg/7-Tl. hr
The amount obtained was 367 kg/7-Ti.

Comparative example 1 Magnesium chloride 2647, titanium tetrachloride 3
．． 67 and co-pulverized in the same manner as in Example 1 to prepare a titanium component.

(Titanium content: 3wt%) Obtained titanium component: 0.20
Polymerization was carried out in the same manner as in Example 1 using 0.107% triethylaluminum as the catalyst component.

Polymerization was stopped after a polymerization time of 3.0 hours, and when the autoclave was cooled and the contents were taken out, a viscous solution could not be passed through the mouth due to the product, so the polymer was precipitated with a large amount of acetone and then passed through the mouth. After drying, polymer 285y was obtained.
The total 1 content of the resulting polymer was 21.3%. Example of upper piston λ Magnesium dichloride 23.67, Titanium tetrachloride. Ethyl benzoate complex 647 was co-pulverized in the same manner as in Example 1 to prepare a titanium component having a titanium content of 3 wt%.

Polymerization was carried out in the same manner as in Example 1 using 0.20 mi of the obtained titanium component and 0.1 mi of triethylaluminum as the catalyst component.

Polypropylene powder 1107 was obtained with a polymerization time of 2 hours. The powder of this polypylene was 70.3%, the intrinsic viscosity was 1.80, and the bulk specific gravity was 0.22. On the other hand, amorphous polypropylene 30 was obtained from the oral fluid.

57 was obtained, the total 1 content of the polymer produced in this polymerization reaction was 55.0%, and the polymerization activity of the catalyst was 11.7k9/7.
1 Tl. The amount of hr obtained was 23.4k9/7-Ti.

Comparative Examples 3 to 4 In order to improve the catalyst system of Comparative Example 2, methyl benzoate was added as the third component of the catalyst system and polymerization was repeated. The results are shown in Table 1.

When ethyl benzoate was added to the catalyst system of Comparative Example 2, 1 of the produced polymer was improved, but not enough, and the activity was greatly reduced. Comparative example 5 Magnesium chloride 24.77, ethyl benzoate 5.37
was co-pulverized in the same manner as in Example 1, and then reacted with titanium tetrachloride and washed with n-heptane in the same manner as in Example 1, to obtain an activated titanium component with a titanium content of 1.21 w%.

Activated titanium component 0.207 Triethyl aluminum 0
．． When polymerization was carried out for 2 hours in the same manner as in Example 1 using 07ml, powdered polypropylene 218y1 and n-heptane soluble surrounding polypropylene 257 were obtained.

Polypropylene powder is 95.0%, bulk specific gravity 0.2
87/Ml,. The intrinsic viscosity was 1.98.

The polymerization activity of the catalyst in this polymerization reaction was 51k9/7-Ti.
The amount of hrl acquired was 101k9/7-Til total 185.2%. Examples 4 to 7 Among the activated titanium component preparation steps of Example 1, ethyl benzoate. Table 2 shows the results of bulk polymerization of propylene in the same manner as in Example 2 using catalysts prepared using various compounds in place of the aluminum chloride complex.

Examples 8-9 The activated titanium component prepared in Example 1 was 0.087 ethyl benzoate 0.157 and the amount of tri-IsO- as shown in Table 3.
Table 3 shows the results of polymerization in the same manner as in Example 1 using butylaluminum as the catalyst component.

Claims (1)

[Scope of Claims] 1 (A) An activated titanium component obtained by treating a composition formed by pulverizing magnesium halide, aluminum halide, and an organic acid ester complex with titanium tetrachloride;
B) A method for polymerizing α-olefins, which comprises polymerizing α-olefins in the presence of a catalyst comprising an organoaluminum compound.