JPH0780940B2 - Method for polymerizing α-olefin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improved polymerization method in which polymerization is carried out using a carrier-type transition metal catalyst, a catalyst comprising an organoaluminum and a stereoregularity improver.

[Prior Art] A number of improved catalysts have been proposed since the method of using a catalyst composed of a carrier-type transition metal, an organoaluminum, and an organic acid ester as a polymerization catalyst for α-olefin was proposed in JP-B-39-12105. It has been proposed, and the catalytic activity and the stereoregularity of the polymer have been greatly improved. It is also known to use trialkylaluminum and dialkylaluminum chloride in combination (Japanese Patent Publication No.
54-7318).

[Problems to be solved by the invention]

However, even when the α-olefin is polymerized by the above method, the activity is insufficient as compared with the ethylene polymerization catalyst and the catalyst residue is not removed at all, and the low stereoregularity, so-called atactic polymer is used. It is difficult to commercialize the product without removing at all, and it is desired to further improve the catalytic activity and stereoregularity.

[Means for Solving the Invention]

The inventors of the present invention have made extensive studies to solve the above-mentioned problems and found that even if the same carrier-type transition metal catalyst is used, it is highly active and highly active due to a specific combination of a specific organoaluminum and a stereoregularity improver. The present invention has been completed by finding that it is possible to produce a stereoregular α-olefin polymer.

An object of the present invention is to provide a method for producing a highly active and highly stereoregular poly-α-olefin.

That is, the present invention uses a catalyst comprising a titanium tetrachloride catalyst supported on a complex of magnesium chloride and a compound containing a C—O bond, a dialkylaluminum chloride, a stereoregularity improver and a trialkylaluminum to form α-
In the method of polymerizing an olefin, an α-characterized in that an aromatic carboxylic acid ester and an organic polysilane compound having an si-si bond are used in combination as a stereoregularity improving agent.
It relates to a method for polymerizing olefins.

There is no particular limitation on the method for producing a titanium tetrachloride catalyst component supported on a complex of magnesium chloride and a compound containing a CO bond, and the obtained catalyst is highly active and highly stereoregular poly-. Any material that gives an α-olefin may be used.

For example, it can be obtained by producing a complex of magnesium chloride and a compound containing a C—O bond, and then subjecting it to heat contact treatment with titanium tetrachloride.

Here, as the compound containing a C—O bond, for example,
Examples thereof include orthoacetates such as ethyl orthoacetate, orthosilicates such as ethyl orthosilicate, alcohols such as 2-ethylhexanol, and aromatic esters such as ethyl benzoate.

This complex of magnesium chloride and a compound containing a C--O bond is usually a method of co-milling a compound containing a magnesium chloride and a C--O bond, mixing liquid magnesium chloride and a compound containing a C--O bond. A method such as using an appropriate precipitant from the solution is used.
It is also possible to coexist a solid compound such as O ₂ , Al ₂ O ₃ , and AlCl ₃ .

Specific examples of the dialkyl aluminum chloride used in the present invention include diethyl aluminum chloride, dipropyl aluminum chloride, dihexyl aluminum chloride and the like. Examples of the trialkylaluminum used in the present invention include triethylaluminum, tributylaluminum, tripropylaluminum, trihexylaluminum and the like.

The present invention is characterized in that an aromatic carboxylic acid ester and an organic polysilane compound having a Si—Si bond are used together as a stereoregularity improving agent.

By using these two kinds of compounds in combination, it becomes possible to provide a polymer having higher activity and higher stereoregularity as compared with the case where they are used alone.

Specific examples of the aromatic carboxylic acid, benzoic acid and an ester of a core-substituted benzoic acid and an alcohol having 1 to 10 carbon atoms, preferably methyl benzoate, ethyl benzoate,
Examples thereof include propyl benzoate, butyl benzoate, methyl toluate, ethyl toluate, propyl toluate, butyl toluate, methyl anisate, ethyl anisate, propyl anisate and butyl anisate.

As the organic polysilane compound having a Si-Si bond, a polysilane having at least one hydrocarbon residue per silicon atom is preferably used. This organopolysilane is preferably obtained by dehalogenation polycondensation of a halogenosilane and / or a halogenodisilane having at least one hydrocarbon residue.

As the organic polysilane, a linear such as cyclohexasilane, which is soluble in an organic solvent, or a polysilane having a long-chain alkyl group such as a cyclic polysilane oligomer, poly-di-n-hexylsilane, or an asymmetry such as polysilane styrene The non-crystalline organic polysilane is preferably used.

In the present invention, the ratio of each of the above components used varies depending on the compound used and the polymerization conditions, but usually 1 to 1000 dialkylaluminum chloride per 1 mol of supported titanium.
Mol, trialkylaluminum is 1 to 2000 mol, stereoregularity improver is 1 to 500 mol, and the ratio of aromatic carboxylic acid ester to organic polysilane compound is 1: 0.1 to 0.1: 1.

The α-olefin polymerized by the method of the present invention includes ethylene, propylene, butene-1, and hexene-1.
It is also used for homopolymerization or mutual copolymerization. As the polymerization temperature and the polymerization pressure, general conditions used in a known method are used, the temperature is 30 ° C. to 100 ° C., and the polymerization pressure is atmospheric pressure to 50 Kg / cm ² -gauge. As the polymerization method, a solvent polymerization method using an inert hydrocarbon, a bulk polymerization method using a liquid monomer as a polymerization medium, or a gas phase polymerization method using no liquid medium can be applied.

〔Example〕

 The present invention will be further described below with reference to examples.

Example 1 A) Production of Support Type Transition Metal Catalyst A vibrating mill equipped with two grinding pots each having an inner volume of 1 liter and containing 300 steel balls having a diameter of 12 mm is prepared. 20 g of magnesium chloride, 1 ml of ethyl orthoacetate, 1 ml of ethyl orthosilicate and 3 ml of 1,2-dichloroethane were added to this pot under a nitrogen atmosphere and pulverized for 20 hours. In a 300 ml round-bottomed flask under a nitrogen atmosphere, 10 g of the above-mentioned pulverized product and 100 titanium tetrachloride
After adding ml and stirring at 85 ° C. for 2 hours, the supernatant was removed by decantation. Furthermore, titanium tetrachloride 100m
l was added and the same operation was repeated. Then n-heptane 200
After adding 15 ml and stirring at room temperature for 15 minutes, the operation of removing the supernatant liquid by decantation was repeated 7 times, and then 200 ml of n-heptane was further added to obtain a carrier-type transition metal catalyst slurry. When 1 part of this slurry was sampled and the titanium content was measured, a carrier-type transition metal catalyst was 1 g.
The content was 2.03% by weight.

B) Polymerization In 1000 ml of n-heptane in an autoclave made of SUS-32 and having an internal volume of 3 L which had been sufficiently dried and replaced with nitrogen, 100 mg of the above carrier-type transition metal catalyst and the additives shown in the table were charged in a propylene atmosphere. The partial pressure of hydrogen was 0.1 kg / cm ² gauge. The contents of the autoclave were heated, and after 5 minutes, the internal temperature was raised to 70 ° C., and polymerization was continued for 2 hours while charging propylene at 70 ° C. so that the polymerization pressure was kept at 5 kg / cm ² gauge.

After cooling the autoclave, unreacted propylene was purged to take out the content and filtered to obtain white powdery polypropylene.

The ratio of the boiling n-heptane extraction residual polymer of the powdery polypropylene (hereinafter abbreviated as powder II), the bulk specific gravity and the intrinsic viscosity number (135 ° C., measured with a tetralin solution, the same applies below) were measured.

On the other hand, the n-heptane-soluble polymer was obtained by concentrating the filtrate. Total II (ratio of boiling n-heptane extraction residual polymer to total produced polymer amount) is total II = powder polymer amount ×
Powder II / (amount of powder polymer + amount of filtrate concentrated polymer)
It asked for by the relational expression. These results are summarized in the table.

Example 4 A) Production of carrier-type transition metal catalyst 10.04 g of anhydrous magnesium chloride, 51.4 ml of white kerosene and 49 ml of 2-ethylhexanol were heated at 130 ° C. for 2 hours to prepare a uniform solution. 2.4 ml of ethyl benzoate was added to this solution,
Then, the above mixture was added dropwise to 400 ml of titanium tetrachloride kept at -20 ° C over 36 minutes and then at 80 ° C for 4 hours.
The temperature was raised to, and 5.12 ml of ethyl benzoate was further added. Then, after stirring at 80 ° C for 2 hours, the mixture was left standing to remove the supernatant, and 400 ml of titanium tetrachloride was added. After the mixture was treated at 90 ° C. for 2 hours and allowed to stand and separate, the operation of removing the supernatant was repeated twice, and the solid component was washed 9 times with n-heptane to obtain a carrier-type transition metal catalyst component. The obtained transition metal catalyst is titanium 3.5 wt%, chlorine 58.5 wt%, magnesium 17.
It contained 0 wt% and ethyl benzoate 15.3 wt%.

B) Polymerization Polymerization was carried out in the same manner as in Example 1 except that the amount of the carrier-type transition metal catalyst was 50 mg. Also, in the same manner, the polymerization of Example 5 and Comparative Example 3 was carried out by changing the additives, and the results are also shown in the table.

〔effect〕

By carrying out the method of the present invention, a polymer having high activity and high stereoregularity as compared with the known method can be obtained. Therefore, compared with the known method, use of an organoaluminum and a stereoregularity improver It is possible to reduce the ratio and has high industrial value.

[Brief description of drawings]

FIG. 1 is a flowchart showing a catalyst adjusting step for helping understanding of the present invention.

Claims (1)

[Claims] 1. A titanium tetrachloride catalyst supported on a complex of magnesium chloride and a compound containing a C—O bond, a dialkylaluminum chloride, a stereoregularity improving agent and a catalyst comprising a trialkylaluminum are used to form α-. In the method for polymerizing an olefin, an α-olefin polymerization method is characterized in that an aromatic carboxylic acid ester and an organic polysilane compound having an si-si bond are used together as a stereoregularity improving agent.