JPH0233045B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for polymerizing ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms in the presence of a highly active Ziegler type catalyst. The present applicant prepared a support by reacting a reaction product of aluminum halide and tetraalkoxysilane with a Grignard compound, and brought the support into contact with titanium tetrahalide to obtain a solid catalyst component and trialkyl aluminum. We have already proposed a method for polymerizing ethylene in the presence of a catalyst obtained from (see JP-A-56-45909). The present invention improves the method proposed above, and provides a method for polymerizing ethylene with a higher yield of polymer per titanium contained in the solid catalyst. That is, the present invention provides (1) aluminum trihalide with the formula R ¹ mSi(OR ² ) _4-n (wherein R ¹ and R ² each have a carbon number of 1
~8 alkyl group, phenyl group or carbon number 7
-10 aralkyl groups, m is 0, 1, 2 or 3. ), and (2) the reaction product is expressed by the formula R ³ MgX ¹ (wherein, R ³ has the same meaning as R ¹ and X ¹ represents a halogen atom). (3) Prepare ^the carrier by reacting it with a Grignard compound of the formula (R ⁴ O)nTiX ² _4-o (wherein R ⁴ has the same meaning as R ¹ , and and n is 1, 2 or 3).
A solid catalyst component (A) obtained by contacting with a titanium compound represented by the formula AlR ⁵ ₃ (wherein R ⁵ represents an alkyl group having 1 to 6 carbon atoms) )
This is an ethylene polymerization method characterized by polymerizing ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms in the presence of a catalyst obtained from According to the invention, ethylene polymers are obtained in significantly higher yields per titanium in the solid catalyst component. For example, when ethylene is polymerized for one hour at an ethylene partial pressure of 7 kg/cm ² and a polymerization temperature of 90° C., the yield of polyethylene per gram of titanium contained in the solid catalyst component reaches about 2000 kg. Further, according to the present invention, an ethylene polymer having a high bulk density can be obtained. The ethylene polymerization method of the present invention and the preparation process of the catalyst used in the polymerization are shown in FIG. In the present invention, the preparation of the solid catalyst component is carried out using substantially anhydrous compounds under an inert gas atmosphere such as nitrogen or argon. Specific examples of aluminum trihalide include aluminum chloride, aluminum bromide, and aluminum iodide, among which aluminum chloride is preferably used. Specific examples of silicon compounds include tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, tetrapentoxysilane, methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-butoxysilane, methyltriisopentoxysilane, and methyltrimethoxysilane. -n-hexoxysilane, methyltriisooctoxysilane, ethyltrimethoxysilane, ethyltriisopropoxysilane, ethyltriisopentoxysilane, n-butyltriethoxysilane, isobutyltriethoxysilane, isopentyltriethoxysilane, isopentyl Tory-n-
Butoxysilane, dimethyldiethoxysilane, dimethyldi-n-butoxysilane, dimethyldiisopentoxysilane, diethyldiethoxysilane,
Diethyldiisopentoxysilane, di-n-butyldiethoxysilane, diisobutyldiisopentoxysilane, trimethylmethoxysilane, trimethylethoxysilane, trimethylisobutoxysilane, triethylisopropoxysilane, tri-
n-propylethoxysilane, tri-n-butylethoxysilane, triisopentylethoxysilane, phenyltriethoxysilane, phenyltriisobutoxysilane, phenyltriisopentoxysilane, diphenyldiethoxysilane, diphenyldiethoxysilane Isopentoxysilane, diphenyldioctoxysilane, triphenylmethoxysilane, triphenylethoxysilane, triphenylisopentoxysilane, trimethylphenoxysilane,
Examples include triethylphenoxysilane, dimethyldiphenoxysilane, benzyltriethoxysilane, dibenzyldiethoxysilane, methyltris(benzyloxy)silane, and the like. The proportion of aluminum trihalide used in the reaction is 0.25 to 10 mol per mol of silicon compound,
In particular, it is preferably 0.5 to 2 mol. The reaction between aluminum trihalide and a silicon compound is usually carried out by stirring both compounds in an inert organic solvent at a temperature in the range of -50 to 100°C for 0.1 to 2 hours. The reaction proceeds with exotherm, and the reaction product is obtained as a solution in an inert organic solvent. The reaction product can be subjected to the reaction with the Grignard compound as the above solution without being isolated. Among Grignard compounds, X
Alkylmagnesium chloride in which is a chlorine atom is preferably used, and specific examples thereof include methylmagnesium chloride, ethylmagnesium chloride, n-butylmagnesium chloride, n-hexylmagnesium chloride, phenylmagnesium chloride, benzylmagnesium chloride, etc. Can be mentioned. The amount of Grignard compound used is 0.05 per mole of silicon compound used for the preparation of the reaction product.
-4 mol, especially 1.5-2 mol is preferred. There are no particular restrictions on the method of reacting the reaction product with the Grignard compound, but an ether solution of the Grignard compound or a mixed solvent solution of ether and an aromatic hydrocarbon may be gradually added to the solution of the reaction product in an inert organic solvent. Conveniently this is done by addition or addition in the reverse order. As the above-mentioned ether, a compound represented by the formula R ⁶ -O-R ⁷ (in the formula, R ⁶ and R ⁷ represent an alkyl group having 2 to 8 carbon atoms) is suitably used, and specific examples thereof include Examples include diethyl ether, diisopropyl ether, di-n-butyl ether, diisoamyl ether, and the like. The reaction temperature is usually -50 to 100℃, preferably -20℃
~25℃. There is no particular restriction on the reaction time, but it is usually 5 minutes or more. As the reaction progresses, the carrier precipitates out. The carrier thus obtained is washed with an inert organic solvent and then subjected to a reaction with a titanium compound. Specific examples of titanium compounds include methoxytrichlortitanium, dimethoxydichlortitanium, trimethoxychlortitanium, ethoxytrichlortitanium, diethoxydichlortitanium, propoxytrichlortitanium, dipropoxydichlortitanium, butoxytrichlortitanium, and dibutoxydichlortitanium. , phenoxytrichlortitanium, diphenoxydichlortitanium, methoxytribromotitanium,
Phenoxytribromotitanium, methoxytriiodotitanium, phenoxytriiodotitanium, benzyloxytrichlortitanium, bis(benzyloxy)dichlorotitanium, tris(benzyloxy)
Examples include chlorotitanium, benzyloxytribromotitanium, benzyloxytriiodotitanium, and the like. The amount of titanium compound used is 1 mole of Grignard compound used in preparing the carrier.
The amount is preferably 2 to 100 moles or more, particularly 2 to 100 moles. The support and the titanium compound can be brought into contact with each other in the presence or absence of an inert organic solvent.
The temperature during contact is 20-200℃, especially 60-140℃.
It is preferable that it is ℃. There are no particular restrictions on the contact time, but it is usually 0.5 to 3 hours. The solid catalyst component is separated from the thus obtained mixture containing the solid catalyst component by filtration, decanting, etc., and washed with an inert organic solvent. The solid catalyst component contains 0.5 to 10% by weight of titanium. Inert organic solvents used in each step of preparing the solid catalyst component include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene, benzene, and xylene, and halides of these hydrocarbons. . In the present invention, ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms is polymerized in the presence of a catalyst obtained from a solid catalyst component and an organoaluminum compound. Specific examples of organoaluminum compounds include triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, etc. Among them, triethylaluminum and triisobutylaluminum are preferably used. The amount of organoaluminum compound used is usually 1 to 1000 per gram atom of titanium in the solid catalyst component.
It is a mole. The polymerization reaction of ethylene can be carried out by a medium-low pressure method or a high-pressure method, and the polymerization by a medium-low pressure method can be carried out in a liquid phase or a gas phase. When carrying out a polymerization reaction in a liquid phase, examples of the polymerization solvent include n-butane, n-propane, n-
Aliphatic hydrocarbons such as hexane and n-heptane,
Alicyclic hydrocarbons such as cyclohexane and cyclopentane, and aromatic hydrocarbons such as benzene and toluene are used. There are no particular restrictions on the catalyst concentration in the polymerization solvent, but in general, the solid catalyst component is 0.0005 titanium metal equivalent per polymerization solvent.
~10 milligram atoms, and for organoaluminum compounds 0.001 to 1000 mmol per polymerization solvent. In the present invention, not only ethylene is polymerized alone, but also ethylene and α-olefin having 3 or more carbon atoms, such as propylene, 1-butene,
It can be copolymerized with 4-methyl-1-pentene, 1-hexene, etc. In the present invention, the polymerization reaction is carried out in a state substantially free of moisture and oxygen, similar to the usual polymerization reaction of ethylene using a Ziegler type catalyst. The polymerization temperature is usually 30 to 300°C, and the polymerization pressure is usually 1 to 3000 Kg/cm ² . In this invention, the molecular weight of the ethylene polymer obtained can be easily adjusted by adding hydrogen to the polymerization system. Next, examples will be shown. In the following description,
"Polymerization activity" is the polymer yield (Kg) per 1 hour of polymerization time per 1 g of titanium contained in the solid catalyst component used in the polymerization reaction, and "MI" is
190 under a load of 2.16Kg/cm ² according to ASTMD1238
Melt flow index measured in °C.
In the Examples, all solid catalyst components were prepared in a dry nitrogen gas atmosphere. Example 1 (1) Preparation of solid catalyst component 30 ml of toluene was added to 15.6 mmol of anhydrous aluminum chloride, and 10 ml of a toluene solution containing 14.5 mmol of phenyltriethoxysilane was added with stirring.
After dropping at 25℃ for 25 minutes, the temperature was raised to 60℃,
Subsequently, the mixture was kept at the same temperature for 1 hour to react. The reaction product mixture was cooled to -11 to -7°C and, with stirring, n-butylmagnesium chloride 27
17.4 ml of diisoamyl ether containing mmol
It was added dropwise to the reaction product mixture over a period of 25 minutes, and then the temperature was raised to 30°C and the temperature was maintained for 60 minutes to allow reaction. The precipitated carrier was separated and washed three times with 30 ml of toluene each time. The carrier was suspended in 30 ml of toluene, 100 mmol of phenoxytrichlortitanium was added to this suspension, and the solid and phenoxytrichlortitanium were brought into contact at 90° C. for 60 minutes with stirring. The treated carrier was separated at the same temperature and washed five times with 30 ml each of toluene and five times with 30 ml each of n-heptane. Obtained solid catalyst component (titanium content: 4.03
% by weight) and 80 ml of n-heptane to prepare a slurry of the solid catalyst component. (2) Polymerization A suspension of the solid catalyst component (4.0
After attaching a glass ampoule containing mg), the air in the autoclave was replaced with nitrogen. 1 ml of n-hexane and then 1.2 ml of n-hexane containing 300 moles of triethylaluminum per gram atom of titanium in the solid catalyst component were introduced into the autoclave and the autoclave contents were
The temperature was raised to 90°C. The internal pressure (gauge pressure, same hereinafter) of the autoclave at this time was 0.9 Kg/cm ² . After introducing ethylene into the autoclave until the total pressure reached 7.9 Kg/cm ² , stirring was started to crush the glass ampoule, and ethylene was polymerized at 90° C. for 60 minutes. Ethylene was continuously fed during the polymerization to maintain the total pressure at 7.9 Kg/cm ² . After the polymerization reaction is completed, unreacted ethylene is released,
The polymer was separated and dried under reduced pressure at 50° C. for 20 hours to obtain 384 g of white polyethylene. Polymerization activity is 1970, density is 0.948g/cm ³ , bulk specific gravity is 0.38
It was hot. Comparative Example 1 A solid catalyst component (titanium content: 4.50% by weight) was prepared in the same manner as in Example 1, except that tetrachlorotitanium was used instead of phenoxytrichlortitanium, and ethylene was polymerized. 140g of white polyethylene was obtained, and the polymerization activity was
670, the density was 0.946 g/cm ³ , and the bulk specific gravity was 0.34. Examples 2-4 1st per gram atom of titanium in the solid catalyst component
Example 1 was repeated except that ethylene was polymerized using triethylaluminum (Al/Ti) in the mole amounts listed in the table. The results are shown in Table 1.

[Table] Examples 5 to 7 Prior to introducing ethylene into the autoclave, hydrogen was introduced under pressure until the hydrogen pressure as shown in Table 2 was reached, and then ethylene was introduced so that the ethylene pressure became 7 kg/cm ² . Example 1 was repeated, except that during the polymerization reaction, ethylene was continuously fed so that the total pressure remained at the initial total pressure. The results are shown in Table 2.

TABLE Examples 8 to 10 Example 1 was repeated, except that instead of phenyltriethoxysilane, 15 mmol of the silicon compound listed in Table 3 was used. Table 3 shows the titanium content of the solid catalyst component and the polymerization results.

[Table] Example 11 Example 1 except that 3.95 mg of the solid catalyst component (titanium content: 3.69% by weight) obtained by using 100 mmol of n-butoxytrichlortitanium instead of phenoxytrichlortitanium was used. repeated. The polymerization activity was 1730, and the bulk specific gravity was 0.38. Example 12 A glass ampoule containing 2.50 mg of the solid catalyst component slurry prepared in Example 1 was attached to an autoclave with an internal volume of 1 and equipped with a stirrer, and then the air in the autoclave was replaced with nitrogen. triethylaluminum 0.630 mmol n-
1.0 ml of heptane solvent and then hydrogen were introduced into the autoclave until the hydrogen pressure reached 5 Kg/cm ² . After pressurizing 100ml of liquid 1-butene and 500ml of n-butane into the autoclave, the contents of the autoclave were heated to 66°C.
The temperature rose to . The autoclave pressure at this time is
It was 17.7Kg/ ^cm2 . The total pressure of ethylene is 28Kg/cm ²
The glass ampoule was introduced into an autoclave until the temperature reached 100.degree. C., stirring was started, the glass ampoule was crushed, and ethylene and 1-butene were copolymerized at 66.degree. C. for 60 minutes. During polymerization, ethylene is continuously supplied to maintain a total pressure of 28Kg/cm ²
I kept it. After the polymerization reaction, unreacted monomers and n-
Butane was released to obtain a white ethylene/1-butene copolymer. The polymerization activity is 1200, the density of the copolymer is 0.928g/cm ³ , the MI is 2.2g/10min, and the bulk specific gravity is
It was 0.34. Example 13 Example 12 was repeated except that the hydrogen pressure was changed to 1 Kg/cm ² and the 1-butene charge was changed to 200 ml. Polymerization activity is 1560, copolymer density is 0.918g/
cm ³ , MI was 0.1 g/10 min, and bulk specific gravity was 0.32.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the ethylene polymerization method of the present invention.

Claims (1)

[Claims] 1 (1) Trihalogenated aluminum and the formula R ¹ _n Si(OR ² ) _4-n (wherein R ¹ and R ² each have a carbon number of 1
~8 alkyl group, phenyl group or carbon number 7
-10 aralkyl groups, m is 0, 1, 2 or 3. ), and (2) the reaction product is expressed by the formula R ³ MgX ¹ (wherein, R ³ has the same meaning as R ¹ and X ¹ represents a halogen atom). (3) The carrier has the formula (R ⁴ O) _o TiX ² _4-o (wherein R ⁴ has the same meaning as R ¹ and X ² is a halogen atom). and n is 1, 2 or 3.)
A solid catalyst component (A) obtained by contacting with a titanium compound represented by the formula AlR ⁵ ₃ (wherein R ⁵ represents an alkyl group having 1 to 6 carbon atoms) ),
A method for polymerizing ethylene, which comprises polymerizing ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms in the presence of a catalyst obtained from