JPH0324484B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved polymerization method using a supported transition metal catalyst, an organoaluminium, and a stereoregularity improver.

Regarding the method of using a catalyst consisting of a supported transition metal, organoaluminium, and organic acid ester as a polymerization catalyst for α-olefin, Japanese Patent Publication No. 39-12105
Since the proposal in the above publication, many improved catalysts have been proposed, and both the catalytic activity and the stereoregularity of the resulting polymers have been significantly improved. However, the activity is insufficient compared to ethylene polymerization catalysts, and it is difficult to commercialize products without thoroughly removing catalyst residue or performing special treatment. Without it, the stereoregularity of the polymer obtained is insufficient, and as a result, the stereoregularity improver remains in the product, causing problems such as odor, so it is desired to improve the catalyst activity or the polymerization method. .

As a result of various studies, the present inventors found that even when using the same carrier-type transition metal catalyst, the yield per carrier-type transition metal catalyst is large depending on the combination of specific organoaluminiums, and that stereoregularity The present invention was completed based on the discovery that poly-α-olefins having high stereoregularity can be obtained by using at least the amount of the improver.

That is, the object of the present invention is to provide a method for producing a poly-α-olefin with high activity and high stereoregularity.

The present invention relates to a method for polymerizing α-olefin using a titanium tetrahalide catalyst supported on magnesium dihalide, a dialkylaluminum chloride, an organic acid ester, and a trialkylaluminium, in which diethyl The present invention relates to a polymerization method characterized by using aluminum chloride and a C ₃ or higher dialkyl aluminum chloride in combination.

There are no particular limitations on the method for producing the titanium halide catalyst component supported on magnesium halide used in the present invention, and any method may be used as long as the resulting catalyst provides a highly active and highly stereoregular poly-α-olefin. Good. For example, magnesium dihalide, preferably magnesium chloride and C-O
Alternatively, it can be obtained by producing a composite with a compound containing a C--N bond, and then subjecting it to a heat contact treatment with titanium tetrachloride.

This composite of magnesium chloride and a compound containing a C-O or C-N bond is usually prepared by co-pulverizing magnesium chloride and a compound containing a C-O or C-N bond, or by co-pulverizing magnesium chloride and a compound containing a C-O or C-N bond.
A method of obtaining it from a mixed solution of a compound containing an O or C-N bond using an appropriate precipitant, etc. is used,
It is also possible to coexist solid compounds such as SiO ₂ , Al ₂ O ₃ and AlCl ₃ .

Examples of organic acid esters used in the present invention include aliphatic carboxylic esters such as acetate, aromatic carboxylic esters such as benzoic ester, and orthocarboxylic esters such as orthobenzoic ester. Group carboxylic acid esters are preferably used.

The dialkylaluminum chloride used in the present invention is a mixture or a combination of diethylaluminum and dialkylaluminium having _C3 or more, and specific examples thereof include dipropylaluminum chloride, dibutylaluminum chloride, dihexylaluminum chloride, and the like.

In the present invention, the amount of each of the above components used varies depending on the compound used and the polymerization conditions, but usually 1 to 1000 mol of dialkylaluminum chloride and stereoregularity improver per 1 mol of Ti in the supported transition metal catalyst. is used in an amount of 1 to 500 mol, and trialkylaluminium is used in an amount of 1 to 2000 mol.

The feature of the present invention is that diethyl aluminum chloride is used as the dialkyl aluminum chloride.
The purpose is to use a dialkylaluminum chloride having an alkyl residue of C ₃ or more in combination, and by this, a highly active and highly stereoregular poly-α-olefin can be obtained with a relatively small amount of stereoregularity improver. . There are no particular limitations on the method of using diethylaluminum chloride and dialkyl aluminum having an alkyl residue of C3 _or more in combination, but it is preferable to mix them in advance. The ratio of diethylaluminum chloride to dialkylaluminum chloride having an alkyl residue of C3 or _more is preferably 9/1 to 1/9, particularly preferably 8/2 to 3/7.

By the above method, propylene, butene-
1. By homopolymerizing α-olefins such as pentene-1 or copolymerizing them with ethylene, stereoregular poly-α-olefins can be obtained in high yield per catalyst, which is industrially valuable. .

A more specific explanation will be given below with reference to Examples.

Examples and Comparative Examples (A) Production of supported transition metal catalyst A vibratory mill equipped with two grinding pots each having an internal volume of 600 ml and containing 80 steel balls with a diameter of 12 mm was prepared. 20 g of magnesium chloride, 2 ml of ethyl orthoacetate, and 4 ml of 1,2-dichloroethane were added to each pot under a nitrogen atmosphere and pulverized for 40 hours. 20 g of the above pulverized product and 100 ml of titanium tetrachloride were added to a 300 ml round bottom flask, and the mixture was stirred at 80° C. for 2 hours, and then the supernatant liquid was removed by decantation. Next, 200 ml of n-heptane was added, stirred at room temperature for 15 minutes, and the washing operation was repeated 7 times to remove the supernatant liquid by decantation.
Next, 200 ml of n-heptane was further added to prepare a carrier-type transition metal catalyst slurry (A). When a portion of this slurry was sampled and Ti was measured, it was found to contain 1.78 wt% per gram of carrier-type transition metal catalyst.

(B) Polymerization 30 mg of the above supported transition metal catalyst and the amount of co-catalyst shown in Table 1 were mixed in 50 ml of n-heptane to make a catalyst slurry, thoroughly dried and purged with nitrogen to make SUS-32 with an internal volume of 5. The autoclave was then charged with 1.5 kg of liquid propylene. Next, 1.6Nl of hydrogen was charged and the autoclave was heated with hot water to raise the internal temperature to 75°C, and polymerization was carried out at 75°C for 3 hours.

After the polymerization was completed, unreacted propylene was discharged to obtain white polypropylene. The obtained polypropylene was dried under reduced pressure and weighed to determine the yield of polypropylene, and the yield of polypropylene per hour was calculated and determined as the activity. In addition, the proportion of boiling n-heptane extraction residue of polypropylene powder,
(hereinafter abbreviated as powder), bulk specific gravity, and limiting viscosity (measured with a tetralin solution at 135°C) were measured. These results are summarized in Table-1.

[Brief explanation of drawings]

The drawing shows a flowchart representing the preparation process of the catalyst of the present invention.

【table】

Claims (1)

[Claims] 1. In a method of polymerizing α-olefin using a titanium tetrahalide catalyst supported on magnesium dihalide, a dialkylaluminum chloride, an organic acid ester, and a trialkylaluminum catalyst, diethylaluminum chloride is used as the dialkylaluminum chloride. A polymerization method characterized by using a C ₃ or higher dialkyl aluminum chloride in combination.