JPH0145484B2 - - 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.

Since Japanese Patent Publication No. 39-12105 proposed a method of using a catalyst consisting of a supported transition metal, an organoaluminum, and an organic acid ester as a polymerization catalyst for α-olefin, many improved catalysts have been proposed. Both the activity and the stereoregularity of the resulting polymers are significantly improved. It is also known to use trialkylaluminum and dialkylaluminum chloride in combination (Japanese Patent Publication No. 54-7318). However, even these catalysts have insufficient activity compared to ethylene polymerization catalysts, and it is difficult to commercialize products without thoroughly removing catalyst residues, and without removing so-called atactic polymers with low stereoregularity. Therefore, it is desired to further improve the catalytic activity and stereoregularity.

As a result of various studies, the present inventors have found that even when using the same supported transition metal catalyst, high activity and high stereoregularity can be achieved by using a specific combination of a characteristic organoaluminum and a stereoregularity improver. The present invention was completed by discovering that it is possible to produce poly-α-olefin.

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

That is, the present invention provides a method for polymerizing α-olefin using a titanium halide catalyst supported on magnesium halide, a dialkylaluminum chloride, a stereoregularity improver, and a catalyst consisting of trialkylaluminium, which improves stereoregularity. As agents, aromatic carboxylic acid esters and general formula R ¹ _o
Si(OR ² ) _4-o (in the formula, R ¹ is a hydrocarbon residue having 1 to 10 carbon atoms, R ₂ is an aliphatic hydrocarbon residue having 1 to 10 carbon atoms)
The present invention relates to a polymerization method characterized in that a silicon compound containing at least one alkoxy group represented by is used 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, as long as the resulting catalyst provides a highly active and highly stereoregular poly-α-olefin. good.

For example, a composite of magnesium chloride, preferably magnesium halide, and a compound containing a C-O or C-N bond is produced, and then heated and catalyzed with a liquid titanium halide, preferably titanium tetrachloride. You can get it.

This composite of magnesium chloride and a compound containing a C-O or C-N bond is usually produced by co-pulverizing magnesium chloride and a compound containing a C-O bond, or by co-pulverizing magnesium chloride and a compound containing a C-O bond. SiO 2 , SiO ₂ ,
It is also possible to coexist solid compounds such as Al ₂ O ₃ and AlCl ₃ .

Specifically, the dialkylaluminum chloride used in the present invention includes diethylaluminum chloride, dipropylaluminum chloride,
Examples include dibutylaluminum chloride and dihexylaluminum chloride.

The trialkyl aluminum used in the present invention includes triethyl aluminum, tributyl aluminum, tripropyl aluminum, and trihexyl aluminum.

In the present invention, aromatic carboxylic acid ester and general formula R ¹ _o Si (OR ² ) _4-o are used as stereoregularity improvers.
(In the formula, R ₁ is a hydrocarbon residue having 1 to 10 carbon atoms, R ² is an aliphatic hydrocarbon residue having 1 to 10 carbon atoms) and is used together with a silicon compound containing at least one alkoxy group. There are certain characteristics.

By using these two types of compounds in combination, it becomes possible to provide a polymer with higher activity and higher stereoregularity than when each is used alone.

Specific examples of aromatic carboxylic acid esters include:
Benzoic acid and esters of nuclear-substituted benzoic acid and alcohols having 1 to 10 carbon atoms are preferably methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, methyl toluate, ethyl toluate, and toluic acid. Examples include propyl, butyl toluate, methyl anisate, ethyl anisate, propyl anisate, butyl anisate.

Silicon compounds containing an alkoxy group include the general formula XnSi(OR) _4-o (wherein X has 1 to 1 carbon atoms)
10 alkyl groups or halogen, R has 1 to 10 carbon atoms
Specifically, orthosilicate esters such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane, diethoxydiethylsilane,
Di- or trialkoxysilanes such as triethoxyethylsilane and triethoxyphenylsilane are preferably used.

In the present invention, the proportions of the above components used vary depending on the compound used and the polymerization conditions, but usually 1 to 1000 mol of dialkyl aluminum chloride and 1 to 2000 mol of trialkyl aluminum are used per 1 mol of supported titanium. , 1 to 500 moles of stereoregularity improver,
The ratio of aromatic carboxylic acid ester to alkoxy silicon compound is 1:0.1 to 0.1:1.

The α-olefins polymerized by the method of the present invention include ethylene, propylene, butene-
1, hexene-1, etc. It is used for homopolymerization or mutual copolymerization. The polymerization temperature and pressure are as follows:
General conditions used in known methods were used, with temperatures ranging from 30°C to 100°C and polymerization pressures ranging from normal pressure to 50°C.
Kg/cm ² - Do this with a 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, and a gas phase polymerization method using no liquid medium can be applied.

By using the method of the present invention, a highly active and highly stereoregular polymer can be produced compared to known methods.
It can be obtained using less organoaluminium and stereoregularity improver compared to known methods, and has great industrial value.

The present invention will be explained in more detail with reference to Examples below.

Examples 1 to 4 and Comparative Examples 1 to 4 (A) Production of carrier type 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. In this pot, under nitrogen atmosphere, 20 g of magnesium chloride, 2 ml of orthoacetate,
4 ml of 1,2-dichloroethane was added and the mixture was ground for 40 hours. 20 g of the above pulverized product and 100 ml of titanium tetrachloride were added to a 300 ml round-bottomed 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, the mixture was stirred at room temperature for 15 minutes, and the supernatant liquid was removed by decantation. The washing operation was repeated 7 times, and then another 200 ml of n-heptane was added to form a carrier-type transition metal catalyst slurry. did. 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 A fully dried and nitrogen-substituted container with an internal volume of 5
n-Heptane in SUS-32 autoclave
A catalyst slurry containing 30 mg of the above supported transition metal catalyst and the additives shown in the table was charged into 50 ml, then 1.5 kg of liquid propylene was charged, and then 1.6 Nl of hydrogen was charged. Next, 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 at 60° C. 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 ratio of boiling n-heptane extrusion residue polymer of polypropylene powder (boiling n-heptane extrusion residue weight/boiling n-heptane weight before extrusion × 100, abbreviated as below), bulk specific gravity, and intrinsic viscosity number (135
℃ measured using a tetralin solution) The results are summarized in the table.

As is clear from the table, polypropylene with high activity can be obtained. Also, by lowering the activity, extremely high polypropylene can be obtained.

[Brief explanation of drawings]

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

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Claims (1)

[Claims] 1. As a stereoregularity improver in a method of polymerizing α-olefin using a catalyst consisting of a titanium tetrahalide catalyst supported on magnesium dihalide, a dialkylaluminum chloride, a stereoregularity improver, and a trialkylaluminium. Aromatic carboxylic acid ester and general formula R ¹ _o Si
(OR ² ) _4-o (In the formula, R ¹ is a hydrocarbon residue having 1 to 10 carbon atoms, R ² is an aliphatic hydrocarbon residue having 1 to 10 carbon atoms)
A polymerization method characterized in that a silicon compound containing at least one alkokene group represented by: is used in combination.