CA1157003A - Process for polymerizing olefin - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
In a process for polymerizing an olefin in the presence of a catalyst system combining an organoaluminum compound with a hydrocarbon insoluble solid catalytic component prepared by treating a hydrocarbon solution containing a magnesium compound, and a titanium compound with an aluminum halide having the formula (R1 represents an alkyl, aryl or cycloalkyl group and X1 represents a halogen atom, and ? is 1 ? ? ? 2), the improve-ment in which the magnesium compound is a compound having the formula (R2 represents an alkyl, aryl or cycloalkyl group; X2 repre-sents a halogen atom; and m is 1 or 2) and the titanium com-pound is a compound having the formula

Description

7C~03 The present invention relates to a process for poly-merizing an olefin. More particularly, it relates to a process for polymerizing an olefin in the presence of a nove!l catalyst system comprising a magnesium compound and a titanium compound.

It is known to use a catalyst system containing a mag-nesium compound and a titanium compound in the polymeri-zati.on of an olefin. For example, it has been proposed to use a catalyst system obtained by reacting magnesium di-ethoxide and titanium tetrabutylate with ethylaluminum di-chloride in Japanese Unexamined Patent Publication 54889/1976 and it has been proposed to use a catalyst system obtained by reacting an acid halide with a hydro-carbon insoluble solid obtained by reacting magnesium diethoxide witha halogen-containing titanium ccmpound in Japanese Unexamined Patent Publication No. 82395/1979. High polymerization activity has been at-tained by polymerizing an olefin in the presence of such a catalyst system.

The inventors have found that the activity of the catalyst for the polymerization can be further improved by preparing a homogeneous hydrocarbon solution containing the magnesium compound and the titanium compound by using the specific titanium compound and then, treating with an organoaluminum halide.

The present invention thus provides a process for polymerizing an olefin in the presence of a catalyst sys-tem combining an organoaluminum compound with a hydro-carbon insoluble solid catalytic component prepared by treating a hydrocarbon solution containing a magnesium com-pound, and a titanium compound, with an aluminum halide having the formula 1 1 AQRQx3-Q

- 2 -.

gl~7~}03 (Rl represents an alkyl, aryl or cycloalkyl group and xl represents a halogen atom, and ~ is 1 Q <2) wherein the magnesium compound is a compound having the formula Mg(OR2 ~m X22 m 5 (R2 represents an alkyl, aryl or cycloalkyl group; x2 represents a halogen atom; and m is 1 or 2) and the titanium compound is a compound having the formula Ti(oR3)n X4 n (R3 represents an alkyl, aryl or cycloalkyl group; X3 represents 10 a halogen atom; and n is 1, 2 or 3), The magnesium compound is a compound having the formula Mg(OR2)m X22~m (R2 represents an alkyl, aryl or cycloalkyl group; x2 represents 15 a halogen atom; and m is 1 or 2).
Suitable magnesium compounds include the magnesium compounds having the formula wherein R2 is an alkyl, aryl or cycloalkyl group having 1 to about 15 of carbon atoms such as methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, phenyl, tolyl, 20 xylyl, and cyclohexyl groups; and x2 is chlorine, bromine or iodine atom for example, dimethoxymagnesium, diethoxymagnesium, ethoxymagnesium chloride and diphenoxymagnesium.
B It is especially preferable to use~magnesium compound having the formula wherein m is 2~especially diethoxymagnesium.
25 The titanium compound is a compound having the formula !
Ti(oR )n X4 -n (R3 represents an alkyl, aryl or cycloalkyl group; X re-presents a halogen atom; n is 1, 2 or 3).

3 3 In the formula, R and X are typically respectively the same with tho~e of R2 and X .

Suitable titanium compounds include diethoxytitanium dichloride, di-n-propoxytitanium dichloride, di-n-butoxy-titanium dichloride where n=2; and triethoxytitanium mono-chloride, tri-n-propoxytitanium monochloride and tri-n-butoxytitanium monochloride where n=3 and ethoxytitanium trichloride where n=l.

It is preferable to use a titanium compound having the formula wherein n is 3 or 2, especially n is 3 such as tri-n-butoxytitanium monochloride.

In the process of the present invention, a hydrocarbon solution contalning the magnesium compound and the titanium compound is prepared.

Suitable hydrocarbons used as solvents include alipha-tic hydrocarbons, such as hexane and heptane; alicyclic hydrocarbons, such as cyclohexane, and especially aromatic hydrocarbons such as benzene, toluene and xylene.

In the preparation of the hydrocarbon solution, the magnesium compound, and the titanium compound, are prefer-ably mixed to form a homogeneous solution. SometLmes, a homogeneous mixture can be obtained by mixing the two components and heating the mixture, however, it it prefer-able to dissolve them in an alcohol when a homogeneous mix-ture is not formed.

35The alcohols may be ethanol, n-propanol, n-butanol, n-pentanol and n-octanol.

~1 .

3L~ )3 The order of the mixing of these two components is not critical and can be selected as desired.

A homogeneous mixture or alcoholic solution can be obtained by mixing them and preferably heating at 100C
to 170C.

Then, a hydrocarbon is added to prepare the hydrocar-bon solution. When an alcohol is used, it is possible to remove the alcohol by, for example, distillation.

In the process of the present invention, the hydro-carbon insoluble solid catalytic component is prepared by treating the hydrocarbon solution with an aluminum halide having the formula (R is an alkyl, aryl or cycloalkyl group; and Xl is a halogen atom and Q is 1 - Q - 2).
In the formula, Rl and Xl are respectively typically the same with those of R2 and X .

The organoaluminum compounds may be methylaluminum dichloride, methylaluminum sesquichloride, dimethylaluminum monochloride, ethylaluminum dichloride, ethylaluminum ses-quichloride, diethylaluminum monochloride, isobutylalumi-num sesq~ichloride and diisobutylaluminum monochloride, especially et~ylalum ~ m dichloride, et~ylanluminum eesquichloride and diethyl-aluminum monochloride. The opt~m effect is attained by using ethyl-aluminum sesquichloride.

The trea ment with the organoaluminum halide may be carried out by adding the organoaluminum halide to the hydrocarbon solution to react them, preferably at 20C to 100C. The hydrocarbon insoluble solid is separated and . :

.
,., . : : : , -.
: . :

:~S~3 - :

washed with the hydrocarbon solvent. The amounts of these components are selected to give X , X , OR , OR , Mg and Ti in the formulas in molar ratios so as to satisfy the following equations:
1 - Mg/Ti - 4 preferably 2 - Mg/Ti 8 3;
1 < Xl + X + X _ 4 preferablY
OR + OR
1.5 _ X 2 X + X3 < 3 OR + OR
The catalyst having high catalytic activity can be obtained in said ranges.
The cocatalyst of the organoaluminum compound is a com-pound having the formula p 3_p ~R4 is an alkyl, aryl or cycloalkyl group; X4 is a halogen atom and p is 1 to 3).

In the formula, R4 and X respectively are typically the same with those of R2 and X2.
Suitable organoaluminum compounds include trialkyl-aluminums, such as triethylaluminum, tri-n-propylaluminum and triisobutylaluminum.

It is preferable to give a ratio of the organoaluminum compound to the hydrocarbon insoluble~solid catalytic com-ponent as an atomic ratio of AQ/Ti of 0.1 to 100 prefer-ably 1 to 20.

The polymerization of the olefin is carried out in the presence of the resulting catalyst system.

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Suitable olefins include ~-olefins such as ethylene, propylene, butene-l, pent~ne-l and octene-l. It is pos-sible to copolymerize two or more olefins.

The process of the present invention is preferably used for preparing an ethylene homopolymer or ethylene copolymer having not more than 20 wt.%, preferably not more than lO wt.% of the co- ~-olefin.

The polymerization of the olefin can be a solution polymerization, a slurry polymerization in an inert sol-vent, or a gaseous polymerization in the absence of a solvent.

Suitable inert solvents include aliphatic hydrocar-bons such as pentane, hexane, heptane, octane, isooctane and cyclohexane and aromatic hydrocarbons such as benzene and toluene.

The polymerization of the olefin is usually conducted at a temperature from room temperature to 250C. The pressure in the polymerization is usually in a range of atmospheric pressure to 200 atm.

When hydrogen is introduced into the polymerization zone, the effect for controlling the molecular weight by hydrogen is remarkably high so as to easily obtain the polymer having suitable molecular weight.

The amount of hydrogen is dependent upon the condi-tions of polymerization and the molecular weight of the desired polyolefin and it should be selected depending upon these factors.

As described above, the advantages of the present in-vention is the use of a novel catalyst having high cataly-. ~ ' ..
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r~ 3 tic activity qiving high productivity and to obtain a poly-mer having xemarkably narrow molecular weight distribu-tion.

The polymer obtained by the process of the present invention using the hydrocarbon soluble component among the reaction products of the magnesium compound and the titanium compound has the advantage that fish-eyes are not usually formed.
The invention will be further illustrated by certain Examples which are provided herein for purpose of illus-tration only and are not intended to be limiting in any manner unless otherwise specified.
In the Examples, the polymerization activity of the catalyst, K value was given as K=(g~polymer/g-catalyst x hr. x olefin pressure Kg/cm2) and the melt index Ml is measured by tne method of ASTM-D-1238-57T under a load of 2.16 Kg. at 190C.

The molecular weight distribution is rated by the flow ratio (hereinafter referring to as FR) which corres-ponds to the shear stress dependency of melt viscosity which is shown by the ratio of melt indexes measured at shear stresses of 106 dyne/cm2 and 105 dyne/cm2 according to ASTM-D-1238-57T. When a flow ratio (FR) is high, a molecular weight distribution is wide whereas when it is low, a molecular weight distribution is narrow.
EXAMPLES 1 to 4:

Diethoxymagnesium, tri-n-butoxytitanium monochloride, and n-butanol were mixed at the ratios shown in Table l and each mixture was stirred at 140C for 4 hours, and then, butanol was removed at 140C with the passage of a nitrogen gas flow and each reaction mixture was cooled to ~ 8 -;.' ~ ~' :

V(33 60C and benzene in an amount shown in Table 1 was added to form a homogeneous solution. Then ethylaluminum ses-quichloride in an amount shown in ~able 1 was added drop-wise to the solution at 60C and each mixture was stirred at ~5C for 1 hour. The resulting precipitate was washed with n-hexane and dried to obtain each catalyst.

In a 2 liter autoclave, 1,000 cc of n-hexane was charged and 5 mg of the catalyst powder was added.
The autoclave was heated to 90~C and hydrogen was fed at a pressure of 1.5 Kg/cm2 and 0.8 m mole of tri-ethylaluminum was fed together with ethylene to give a total pressure of 5 Kg/cm . A consumption of ethylene resulted during the feeding time of ethylene. Additional ethylene was fed to maintain a total pressure of 5 Kg/cm2 and the polymerization was stopped by adding ethanol under the pressure after 1 hour~ The results are shown in Table 1.
EXAMPLES S and 6:

In accordance with the process of Examples l to 4 except that n-butanol was not used to prepare each hydro-carbon solution having the components shown in Table 1and the solution was treated with ethylaluminum sesqui-chloride to obtain each solid powder, the polymerization of ethylene was carried out by using 5 mg of the solid powder.
The results are shown in Table 1.
EXAMPLES ~ and 8:

In accordance with the process of Example 1 except that ethylaluminum dichloride or diethylaluminum mono-chloride was used at the ratio shown in Table 1 instead ofethylaluminum sesquichloride, each solid powder was _ g _ ~' .~
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7C~(~3 obtained and the polymerization of ethylene was carried out by using 5 mg of the solid powder. The results are sho~wn in Table 1.

EXA~æLES 9 and 10:

In accordance with the process of Example 5 except that ethylaluminum sesquichloride was added dropwise at 20C in Example 9 and 100C in Example 10, each solid powder was obtained and the polymerization of ethylene was carried out by using 5 mg of the solid powder. The results are shown in Table 1.

EXAMPLE 11:

In accordance with the process of Example 1 except that the reaction temperature was changed from 90C to 70C
and butene-l was added during the feeding and the addi-tional feeding of ethylene to give a molar ratio of butene-l to ethylene of 0.06 in the gaseous phase during the poly-merization, the copolymerization of ethylene and butene-l was carried out. The result is shown in Table 1. The resulting polymer was a copolymer of ethylene-butene-l having 1 mol % of butene-l units.

EXAMPLE 12:

In a 2 liter autoclave, 1,000 mQ of n-hexane was charged and 5 mg of the solid powder obtained in Example 1 was charged. The mixture was heated at 90C and hydrogen was fed to a pressure of 21 Kg/cm2 and 0.08 m mol of tri-ethylaluminum was fed together with ethylene to give a total pressure of 26 Kgjcm . A consumption of ethylene was resulted during the feeding time of ethylene. Additional et~ylene was fed to maintain a total pressure of 26 Kg/cm and the polymerization was carried out for 34 minutes.

7'~(~3 During the time, 193 g of ethylene was polymerized. The temperature was reduced to 70C and ethylene and hydrogen were purged to give a total pressure of 0.4 Kg/cm2 and thenl 12 g of butene-l was fed together with additional feed:ing of ethylene to maintain a total pressure of 2.0 Kg/cm2 for 68 minutes. The polymerization was stopped by compxess-feeding ethanol to obtain 386 g of a copolymer of ethylene and butene-l. The resulting polymer was pel-letized by an extruder.
The pellets had Ml of 0.03 and FR of 95. According to infrared spectrography analysis, 0.7 mol % of butene-l units was included. When a film was prepared by using the pellets, fish-eyes were not found.
EXAMPLE 13:

Diethoxymagnesium, tri-n-butoxytitanium monochloride, and n-butanol were mixed at ratios shown in Table 1 and each mixture was stirred at 140C for 4 hours, and then, cooled to 60C and benzene in an amount shown in Table 1 was added to form a homogeneous solution. Then ethylalu-minum sesquichloride in an amount shown in Table 1 was added dropwise to the solution at 60C and each mixture was stirred at 65C for 1 hour. The resulting precipi-tate was washed with n-hexane and dried to obtain each catalyst.

In a 2 liter autoclave, 1,000 cc of n-hexane was charged and 5 mg of the catalyst powder was added.

The autoclave was heated to 150C and hydrogen was fed to the pressure up to 8.0 ~g/cm2 and 0.8 m mol of tri-ethylaluminum was fed together with ethylene to give a total pressure of 12 k~/cm . A consumption of ethylene resulted during the time feeding ethylene. Additional -- 11 -- .

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li57(:}~3 ethylene was fed to maintain a total pressure of 12 kg/cm2 and the polymerization was stopped by adding ethanol under the pressure after 1 hour. The results are shown in Table l.
REFERENCE 1:

In accordance with the process of Example 6 except that diethoxymagnesium and tri-n-butoxytitanium monochloride were not heat-treated at 140C and benzene was added to form a benzene slurry, a solid powder was obtained.

In accordance with the process of Example 1 except using 5 mg of the resulting solid powder, the polymeriza-tion of ethylene was carried out to obtain 89.1 g of poly-ethylene. As a result, K=6,600, KTi=59,400, Ml=0.70 and FR=23. The product had non-uniform parts such as fish-eyes in the texture.

REFERENCE 2:

The components used in Example 6 were used. Diethoxy-magnesium was added to benzene to obtain a slurry, then, ethylaluminum sesquichloride was added at 60C and then, tri-n-butoxytitanium monochloride was added dropwise and the mixture was stirred at 65C for l hour. The mixture was treated as the process of Example l to obtain a solid powder.

In accordance with the process of Example 1 except using 5 m~ of the resulting solid powder, the polymeriza-tion of ethylene was carried out to obtain 26 g of poly-ethylene. As a result, K=1,940, KTi=19,800, Ml=0.85 and FR=22. The product had fish-eyes in its texture.

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:~ ' Table 1 ! I Example 2 1 3 _ 4 5 6 n~ comD (m mol 20 30 Z0 20 20 20 I ~ ~
! Ti com p . (m m ol ) 10 10 10 10 20 ] 0 ~lcohol (m mol~ 40 60 40 40 none none Solvent (cc) 150 200 150 150 200 150 . Organoaluminum 87 113 133 40 120 87 halide (m mol) Yield of polymert~ 281 Z36 283 210 213 261 . K 20,840 17,500 20,950 15,530 15,800 19,340 KTi 89,450 _ 190, 690 194,130 112,860 176,500 . . ..
MI 0.27 0.35 0.25 0.33 0.25 0.25 Fish-eye~ I none none none none none none Table 1 (continued) Exam le 1 7 8 9 10 11 13 P _ Mg. comp. (m mol, 20 Z0 20 20 20 20 Ti comp. (m mol) 10 10 20 20 10 10 Alcohol (m mol) 40 40 none none 40 10 Solvent (cc) 150 150 200 200 150 150 Organoaluminum ¦65 130 120 120 87 107 halide (m mol) I
~ .
yield of polymer(g 180 209 226 201 295 102 K 13,30015,50016,760 14,860 21,820 5.100 KTi 134, 500167,700179,900135,200198,56046,360 MI _ 0.26 0.29 0.29 0.26 1.5 3.

.
Fish-eyes . none none none none none none

Claims (7)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a process for polymerizing an olefin in the presence of a catalyst system combining an organoaluminum compound with a hydrocarbon insoluble solid catalytic com-ponent prepared by treating a hydrocarbon solution con-taining a magnesium compound and a titanium compound, with an aluminum halide having the formula R1 represents an alkyl, aryl or cycloalkyl group and X1 represents a halogen atom, and ? is 1? ? ? 2, the improve-ment in which the magnesium compound is a compound having the formula wherein R2 represents an alkyl, aryl or cycloalkyl group;
X2 represents a halogen atom; and m is 1 or 2, and the titanium compound is a compound having the formula wherein R3 represents an alkyl, aryl or cycloalkyl group;
X3 represents a halogen atom; n is 1, 2 or 3.

2. A process for polymerizing an olefin according to claim 1, wherein the magnesium compound is a compound having the formula Mg(OR2)2 and the titanium compound is a compound having the formula Ti(OR3)3X3 where R2 , R3 and X3 are as in claim 1.

3. A process for polymerizing an olefin according to claim 1, wherein the magnesium compound is diethoxymagnesium and the titanium compound is tri-n-butoxytitanium mono-chloride.

4. A process for polymerizing an olefin according to claim 1, wherein the aluminum halide is ethylaluminum dichloride, ethylaluminum sesquichloride or diethylaluminum chloride.

5. A process for polymerizing an olefin according to claim 1, wherein the magnesium compound and the titanium compound are mixed with an alcohol to form a homogeneous solution, the alcohol is then removed and a hydrocarbon solvent is added to prepare the hydrocarbon solution.

6. A hydrocarbon insoluble solid catalytic component prepared by treating a hydrocarbon solution containing a magnesium compound and a titanium compound, with an aluminum halide having the formula where R1 represents an alkyl, aryl or cycloalkyl group and X1 represents a halogen atom, and ? is 1 ? ? ? 2, the improvement in which the magnesium compound is a compound having the formula where R2 represents an alkyl, aryl or cycloalkyl group; X2 represents a halogen atom; and m is 1 to 2 and the titanium compound is a compound having the formula where R3 represents an alkyl, aryl or cycloalkyl group; X3 represents a halogen atom; and n is 1, 2 or 3.

7. In a process for preparing a hydrocarbon insoluble solid catalytic component, which comprises treating a hydrocarbon solution containing a magnesium compound and a titanium compound, with an aluminum halide having the formula where R1 represents an alkyl, aryl or cycloalkyl group and X1 represents a halogen atom, and ? is 1 ? ? ? 2, the improvement in which the magnesium compound is a compound having the formula where R2 represents an alkyl, aryl or cycloalkyl group; X2 represents a halogen atom; and m is 1 to 2 and the titanium compound is a compound having the formula where R3 represents an alkyl, aryl or cycloalkyl group; X3 represents a halogen atom; and n is 1, 2 or 3.