CS197251B2 - Method of producing catalyst for alpha-olefins polymerisation - Google Patents

Abstract

PURPOSE:To produce a poly-alpha-olefin having high stereoregularity using a highly active catalyst system prepared by adding an organoaluminum compound and and aluminum halide-ester of an organic acid complex to the activated titanlum component.

Description

The present invention relates to a catalyst for the polymerization of α-olefins, and more particularly to a catalyst consisting of a titanium component deposited on magnesium compounds, an organoaluminum compound and an aluminum halide complex with a carboxylic acid ester.

A process for the polymerization of α-olefins, such as propylene, butene or the like, to stereoregular poly-α-olefins using a so-called Ziegler-Natta titanium tetrachloride catalyst and an organoaluminum compound is well known and commercially utilized.

Recently it has been significantly. Improved polymerization activity of the Ziegler-Natta catalyst by depositing the titanium component of the catalyst on a support and such catalysts is generally used as polymerization catalysts for ethylene. However, when a well known type of catalyst support is used to polymerize higher α-olefins such as propylene, butylene and the like, it is difficult to obtain a polymer having an isotactic structure and the use of the catalyst is not practical because it cannot be obtained appropriately. a polymer having higher crystallinity. Therefore, the technically important problem of how to improve. a catalyst to be able to maintain the crystallinity of the resulting polymer and to have a high catalytic activity.

The procedures described in Japanese Publication Nos. 9342/72, 16986/73 and

86482/74, an improvement in the crystallinity of the resulting polymer is achieved by adding an organic electron donor compound as a third component to a supported catalyst type comprising a titanium component supported on a magnesium halide and an organoaluminum compound.

In the polymerization of propylene with a two-component type catalyst comprising a titanium component deposited on a. and the organic aluminum compound, the crystallinity of the resulting polymer is extremely low despite the high polymerization activity of the catalyst.

Although the crystallinity of the resulting polymer is improved by the addition of an organic electron donor compound to the catalyst, the above process is practically unsatisfactory since the polymerization activity of the catalyst is greatly reduced and furthermore the improvement in crystallinity is still unsatisfactory and therefore difficult to produce crystalline. polypropylene having the same quality as the polymer produced with the now industrially utilized catalyst containing titanium chloride and diethylaluminum monochloride.

In investigating how to produce highly crystalline poly-α-olefins in high yield, the inventors have discovered that a catalyst composed of

A) titanium compounds deposited on a magnesium compound,

(B) organo-clay compounds,

c) a complex of a carboxylic acid ester with an aluminum halide is very effective for the polymerization of α-olefins.

It is an object of the present invention to provide a process for the preparation of a catalyst for the polymerization of α-olefins, which comprises grinding together without taking into account the order of addition;

(a) component A, obtained by depositing a titanium compound on magnesium halide, where the titanium component contains 0,1 to 10% by weight of titanium,

(b) an organoaluminum compound of formula (B);

Al R _m ¹ H 3_ _m (B) where

R 1 is an alkyl radical having 1 to 12 carbon atoms and m is a number defined by 1.5 to 3, and wherein the atomic ratio of titanium to aluminum of the titanium atoms contained in component A to aluminum atoms in organoaluminum compound B is in the range 1: 1 to 1: 500, and cj complex C consisting of an aluminum halide and a carboxylic acid ester of the general formula

R ² COOR ³ , where is

And R2

R ^{3 is an} aliphatic or alicyclic radical.

A detailed description of the possible embodiments of the method according to the invention is given below.

In the known process, the addition of an organic electron donor compound to the catalyst forms an electron-providing organic compound complexed with the titanium component and / or the organoaluminum compound. This improves the crystallinity of the resulting polymer, but the polymer yield is extremely reduced due to the electron donor effect of the organic compound. Conversely, according to the present invention, a high crystallinity of the polymer can be achieved at a simultaneously high yield using a catalyst comprising a carboxylic acid complex with an aluminum halide instead of an organic compound as an electron donor.

The titanium compound used as component A1 according to the invention is deposited on the magnesium compound. As the magnesium compound, magnesium halide, magnesium oxide, magnesium hydroxide, magnesium hydroxyhalide and the like can be used. Preferably, the titanium compound used is titanium tetrachloride, titanium tetrachloride, and the complex of the electron-providing organic compound and the above-mentioned chlorides.

While various methods can be used to deposit the titanium compound on the magnesium compound, the methods described below are a typical example. Application is carried out either physically or chemically.

1. The magnesium compound is comminuted with the titanium compound. In this case, compounds such as optionally metal compounds, organic electron-donating compounds, silicon tetrachloride, polysiloxane and a carboxylic acid ester complex may be added. aluminum halide.

2. The mixture of titanium tetrachloride and magnesium compound is heat treated. In this case, the magnesium compound is suspended in titanium tetrachloride for several minutes to several hours at 40 to 135 ° C.

3. A preformed mixture of a magnesium compound and an electron donating organic compound or a complex of a metal compound and an electron donating organic compound is thermally heated. treated with titanium tetrachloride.

The preparation of the component A) mentioned in the case 1) and the pre-prepared mixture mentioned in the case. 3) can be carried out by grinding using a mill suitable for this purpose, such as a ball mill or a vibratory mill.

The comminution operation is carried out in a vacuum or inert atmosphere and should be carried out under conditions where moisture, oxygen and the like are completely removed. .

As a grinding condition, it is convenient to maintain a temperature of 0 to 50 ° C and a period of 2 to 100 hours.

In the case where component A) is prepared directly by the simultaneous comminution process as described in case 1), the raw material may be mixed in such a ratio that the resulting component A) contains 0.1 to 10% by weight. % titanium.

In the heat treatment of a mixture of a magnesium compound and a titanium tetrachloride, as mentioned in case 2], a magnesium compound such as magnesium hydroxychloride, magnesium oxide and magnesium hydroxide is usually suspended in. titanium tetrachloride.

In the case of 3), the previously prepared mixture is suspended in titanium tetrachloride.

In cases 2) and 3), the titanium component A) can be obtained by a process in which the aforementioned magnesium compound or a preformed mixture containing the magnesium compound is suspended in titanium tetrachloride or a mixture thereof with an inert solvent, subjected to a heat treatment at 40-135 ° C and then optionally the remaining free titanium tetrachloride is eluted with an inert solvent or distilled under reduced pressure. The component A) thus obtained usually contains 0.1 to 10% by weight of titanium.

Component B) in the catalyst of the invention is an organoaluminum compound of the formula

AlR'- _ni H, nn where

R 1 represents an alkyl radical having 1 to 12 carbon atoms and m is a number defined by 1, 5 and 3.

As this component, for example, trimethyl aluminum, triethyl aluminum, tri-n-butyl aluminum, triisobutyl aluminum, trl-n-hexyl aluminum, diethylaluminum hydride and the like can be used.

The ratio of the titanium component forming component A) to the organoaluminum compound can vary within wide limits. Typically, the molar ratio of titanium atoms to organoaluminum compound may vary in the range of Ti: Al - 1: 1 to 500, and preferably 1: 20 to 100, to improve catalyst activity.

Component C) may be a complex formed from an ester of a carboxylic acid with an aluminum halide. For the preparation of component C), aluminum chloride and aluminum bromide are used as particularly preferred aluminum halide.

The carboxylic acid ester may be represented by the formula

R2COOR ³ where

R2 and ^R3 are as defined above.

For example, methyl benzoate, ethyl benzoate, propyl benzoate, phenyl benzoate, ethylanisate, ethyl naphthoate, ethyl acetate, ethyl acrylate, ethyl methacrylate, ethyl hexahydrobenzoate and the like can be used. The aluminum halide / carboxylic acid ester complex can be prepared by a known method, for example by mixing the raw materials at room temperature or by heating the mixture.

The catalyst of the present invention can be used to polymerize α-olefins of the general formula R 4 -CH = CH 2 wherein

R ⁴ represents an alkyl radical of 1 to 10 carbon atoms, for example for the homopolymerization of α-olefins, copolymerization of α-olefins and copolymerization of α-olefin and ethylene.

As the above-mentioned olefins, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and the like can be mentioned.

The polymerization method of the present invention can be carried out under conditions commonly used on a commercial scale; the polymerization temperature is in the range of 20 to 300 ° C, preferably up to 200 ° C and the pressure in the range of 0.1 to 20 MPa, preferably 0.1 to 15 MPa. Aliphatic, alicyclic or aromatic hydrocarbons, individually or in the form of a mixture thereof, can be used as polymerization solvent in the polymerization. These hydrocarbons are preferably propane, butane, pentane, hexane, heptane, cyclohexane, benzene, toluene and the like or mixtures thereof. Furthermore, a solubilized liquid α-olefin can be used as the solvent for the polymerization in the mass. In addition, the catalyst according to the invention can also be used in the so-called gas phase polymerization, which is carried out by contacting the α-olefin gas with the catalyst substantially in the absence of a solvent.

The molecular weight of the resulting polymer varies depending on the polymerization method, the catalyst used and the polymerization conditions, and can be controlled, for example, by the addition of hydrogen, an alkyl halide, a dialkylzinc and the like.

The following examples further illustrate the invention.

Examples 1, 2 and 3

The 600 ml crushing mill is equipped with 80 12 mm steel balls.

20.0 g of magnesium chloride and 10.0 g of aluminum chloride-ethylbenzoate complex under nitrogen are introduced into the working space and ground for 20 hours.

10 g of the above powder mixture and 200 ml of titanium tetrachloride are added to a 300 ml round bottom flask and the contents are stirred at 80 ° C for 2 hours. The upper layer of liquid from the flask was then removed by decantation and then 200 ml of n-heptane was added and the contents were stirred at room temperature for 30 minutes. After mixing the contents are removed from the flask by decantation. This wash is repeated seven times. An additional 200 ml of n-heptane is then added to obtain a slurry containing the activated titanium component.

A portion of the suspension was collected as a sample, n-heptane was evaporated and the components were determined by analysis. The analysis shows a content of 1.2% by weight of titanium in the updated titanium component.

A 2 liter SUS-32 autoclave (stainless steel referred to as the Japanese Industrial Standard) is charged with 1 liter of n-heptane, 0.10 g of the above activated titanium component (0.025 mg-atom, expressed as titanium), 0.2 ml (1 (45 mmol) of triethylaluminum and a predetermined amount of aluminum halide / ethylbenzoate complex under a nitrogen atmosphere.

After evacuation of the nitrogen present from the autoclave by means of a vacuum pump, hydrogen is introduced into the autoclave at a partial pressure of 30 kPa and then the gas phase of propylene at an overpressure of 0.2 MPa. The contents of the autoclave are heated in such a way that the internal temperature rises to 70 ° C. Celsius after 5 minutes and the polymerization was continued for 2 hours while propylene was metered in to maintain an overpressure of 0.5 MPa at 70 ° C during polymerization.

After cooling the autoclave, unreacted propylene is removed, the contents are filtered and then dried under reduced pressure at 60 ° C. Celsius. A white powdered polypropylene is obtained.

Non-crystalline n-heptane soluble polypropylene is obtained by concentrating the filtrate.

The weight, ratio of residual polymer that can be obtained when subjected to extraction with boiling n-heptane (hereinafter referred to as powdered substance II) to polypropylene, its viscosity limit value (determined in tetralin solution at 135 ° C) and the bulk mass. Furthermore, the yield of powdered and non-crystalline polypropylene is determined. The total isotacticity index represented by the weight ratio of the above residual polymer to total polymer (hereinafter referred to as whole II) is calculated from the value of the powdered substance II.

The results from tests carried out using varying amounts of ethyl8 benzoate-aluminum chloride complex are shown in Table 1.

Example 4

A similar test to that described in Example 2 was performed with this. except that instead of triethyl aluminum, 0.35 ml of triisobutyl aluminum is used. The results are shown in Table 1.

Comparative Examples 1, 2 and 3

Experiments similar to those described in Examples 1, 2, 3 and 4 were performed except that. ethyl benzoate is used instead of the ethyl benzoate-aluminum halide complex as component C) of the catalyst of the invention. The results are shown in Table 2.

Experiment-Number Amount Poles-Yield Yield-No Activity Amount Analytical values of the measurement (s) of the crystalline catalyst powder obtained.

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Example 5

An activated titanium component containing 1.5% by weight of titanium was prepared by simultaneously grinding 26.8 g of magnesium chloride and 3.2 g of titanium tetrachloride-ethylbenzoate complex in the same manner as described in Example 1.

The polymerization was carried out as described in Example 1, using a catalyst consisting of 0.10 g of the resulting activated titanium component, 0.20 ml of triethyl aluminum and 0.10 g of ethyl benzoate-aluminum chloride complex.

After polymerization for 2 hours, 224 g of polypropylene powder are obtained.

The amount of powder II in the powder is 96.3%, the intrinsic viscosity is 1.89 dl / g and the bulk density is 0.32 g / ml.

In addition, 11 g of non-crystalline polypropylene is recovered from the filtrate. The total II polymer formed during the polymerization was 92.0%, the catalyst activity was 98 kg / g Ti per hour, and the amount was 195 kg / g titanium.

Comparative Examples 4, 5 and 6

In the same manner as described in Example 4, propylene polymerization is carried out, except that ethylbenzoate-aluminum chloride complex is not added as component C) of the catalyst, but ethylbenzoate is used instead.

The results are shown in Table 3.

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Example 6

Polypropylation of propylene in the mass is performed using an activated titanium component prepared in the same manner as described in Example 1.

0.10 g of activated is charged into a six-liter autoclave from SUS-32. titanium components suspended in 30 ml n-heptane, 0.2 ml triethyl aluminum and 0.10 g ethylbenzoate-aluminum chloride complex.

After evacuation of the nitrogen present from the autoclave by means of a vacuum pump, 2.5 kg of propylene and 0.5 Ni of hydrogen are metered in. The contents of the autoclave are heated in such a way that:. the internal temperature rose to 75 ° C after 5 minutes and the polymerization lasted 3 hours at 75 ° C.

After cooling the autoclave, unreacted propylene is removed to extract the contents, which are then dried under reduced pressure to give 983 g of polypropylene powder.

The total II of the resulting polypropylene powder is 93.3%, the viscosity limit number

1.77 µl / g and bulk density 0.36 g / ml.

The polymerization activity of the catalyst used in the polymerization is 273 kg / g. of titanium per hour and the amount of polymer recovered was 820 kg / g of titanium.

Examples 7, 8, 9 and 10

In the polymerization stage of Example 6, various kinds of mixtures were used instead of the ethylbenzoate-aluminum chloride complex.

Results achieved at. polymerization in matter. carried out with these catalysts. are given in Table 4.

Table 4

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Example 11

The activated titanium component is prepared by co-grinding 20 g of aluminum chloride and 8.4 g of ethyl benzoate-aluminum chloride complex, followed by 1.6 g of titanium tetrachloride for 20 hours in the same manner as described in Example 1. 5 wt% titanium.

The bulk polymerization was carried out in the same manner as described in Example 6 except that the activated titanium component described above was used.

The whole of the resulting polypropylene is II

92.5 ° / o, bulk density 0.34 g / ml, viscosity limit value 2.01 dl / g and a yield of 760 grams.

The activity of the catalyst used in the polymerization was 169 kg / g of titanium per hour and the amount of 506 kg / g of titanium.

Comparative example 7

The polymerization according to the procedure described in Example 11 was repeated except that 0.05 g (0.25 mmol) of benzoic acid was used instead of the ethylbenzoate-aluminum chloride complex. Total II of the resulting polypropylene is 88.0%, bulk density 0.33 g / ml, viscosity limit value 1.93 dl / g and polypropylene yield 403 g.

The activity of the catalyst used in the polymerization is 90 kg / g of titanium per hour and its amount is 286 kg / g of titanium.

SUBJECT

A process for the manufacture of a catalyst for the polymerization of α-olefins, wherein the catalyst comprises a component A of a titanium compound deposited on a magnesium halide, characterized in that it is comminuted without regard to the order of addition,

(a) component A, obtained by depositing a titanium compound on magnesium halide, where the titanium component contains 0,1 to 10% by weight of titanium,

(b) an organoaluminum compound of formula (B);

AlVHs-m (B) wherein

R ¹ represents an alkyl radical having 1 to 12 carbon atoms and m is a number defined by 1.5 µm ^ 3, and wherein the atomic ratio of titanium to aluminum of the titanium atoms contained in component A to the aluminum atoms of organoaluminum compound V is in the range of 1 : 1 to 1: 500, and

Claims (4)

c) an aluminum halide complex C and a carboxylic acid ester of the general formula C R ² COOR ³ , where is R ² aromatic radical and R ^{3 is an} aliphatic or alicyclic radical. 2. The method of claim 1, wherein the titanium component is produced by co-grinding a mixture of a magnesium compound and a titanium compound, wherein the titanium component comprises 0.1 to 10% by weight of titanium. 3. The process of claim 1 wherein the titanium component is produced by heat treating a co-comminuted mixture of a magnesium compound and an organic compound, such as an electron donor, or a complex of an organic compound, such as an electron donor and a metal compound with titanium tetrachloride. 4. The process of claim 1 wherein the complex is a carboxylic acid ester and aluminum chloride.