JPH0153892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a process for making ethylene copolymers.
More specifically, the present invention provides a method for producing ethylene copolymers with a low fraction of polymer soluble in organic solvents in significantly higher yields per catalyst by copolymerizing ethylene and alpha-olefins in the presence of novel catalysts. Relating to a method of manufacturing.

Many proposals have been made regarding methods for producing linear low-density ethylene copolymers by copolymerizing ethylene and α-olefins having 3 or more carbon atoms in an inert organic medium.

In the proposed method, the organic solvent soluble content of the produced ethylene copolymer is generally relatively large, so the polymer adheres to the walls of the polymerization reactor, making it difficult to remove the polymerization reaction heat, and the polymer transfer. There are problems in that the tubes may become blocked or the polymer may form into clumps that are difficult to handle. Furthermore, in the proposed method, the yield of ethylene copolymer per catalyst used is small, and an operation to remove catalyst residue from the produced copolymer is essential. Further, after the copolymerization reaction is completed, it is necessary to purify the inert organic medium and reuse it.

The present invention provides a method for producing ethylene copolymers that overcomes the problems of previously proposed methods.

That is, the present invention provides trihalogenated aluminum and a compound having the formula R ¹ _o Si (OR ² ) _4-o (wherein R ¹ represents an alkyl group or phenyl group having 1 to 8 carbon atoms, and R ² represents a carbon number 1 to 8 alkyl group, and n is 1, ² or ³ ). A solid catalyst component obtained by contacting a Grignard compound represented by the formula AlR ⁴ ₃ (wherein R ⁴ represents an alkyl group having 1 to 6 carbon atoms). Ethylene and an α-olefin having 3 or more carbon atoms are mixed into a slurry of the α-olefin in a liquid phase. This is a method for producing an ethylene copolymer, which is characterized by copolymerizing the ethylene copolymer to obtain a copolymer containing 1 to 12% by weight of α-olefin.

FIG. 1 shows the method for producing the ethylene copolymer of the present invention and the process for preparing the solid catalyst component used in the polymerization.

According to the present invention, as can be seen from the results of Examples described later, it is possible to obtain an ethylene copolymer having a low soluble fraction in organic solvents in an extremely large yield per catalyst used. Therefore, according to the present invention, the production of ethylene copolymers can be carried out smoothly without any problems, and the operation of removing catalyst residues from the produced copolymers is completely eliminated or significantly reduced. In addition, in the present invention, α
- Since the olefin also serves as a polymerization solvent, the purification and recovery process after the copolymerization reaction is simplified.

The catalyst used in the present invention is described in Japanese Patent Application No. 56-26102 (Japanese Patent Publication No. 59-49242 filed by the present applicant).
It can be prepared by the method described in the following publication.

Specific examples of aluminum trihalide include aluminum chloride, aluminum bromide, and aluminum iodide, among which aluminum chloride is preferably used.

Specific examples of organosilicon compounds include methyltrimethoxysilane, methyltriethoxysilane,
Methyltri-n-butoxysilane, methyltriisopentoxysilane, methyltri-n-hexoxysilane, methyltriisooctoxysilane, ethyltriethoxysilane, ethyltriisopropoxysilane, ethyltriisopentoxysilane,
n-butyltriethoxysilane, isobutyltriethoxysilane, isopentyltriethoxysilane, isopentyltri-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, diphenyldiisopentoxysilane, diphenyldioctoxysilane, triphenyl Examples include methoxysilane, triphenylethoxysilane, and triphenylisopentoxysilane.

The proportion of aluminum trihalide used in the reaction is preferably 0.25 to 10 mol, particularly 0.5 to 2 mol, per mol of organosilicon compound.

The reaction between aluminum halide and organosilicon 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, alkylmagnesium chlorides in which X is a chlorine atom are preferably used, and specific examples include methylmagnesium chloride, ethylmagnesium chloride, n
-butylmagnesium chloride, n-hexylmagnesium chloride, and the like.

The amount of Grignard compound used per mole of organosilicon compound used for the preparation of the reaction product is:
It is preferably 0.05 to 4 mol, particularly 1.5 to 2 mol.

There is no particular restriction 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 is 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 ⁵ -O-R ⁶ (in the formula, R ⁵ and R ⁶ represent an alkyl group having 2 to 8 carbon atoms) is preferably used, and specific examples thereof include: Examples include diethyl ether, diisopropyl ether, di-n-butyl ether, and diisoamyl ether.

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, a white solid precipitates out. Although the solid thus obtained can be contacted with titanium tetrahalide as a reaction product mixture, it is preferable to wash the produced solid with an inert organic solvent before contacting with titanium tetrahalide.

Specific examples of titanium tetrahalide in this invention include titanium tetrachloride, titanium tetrabromide, and titanium tetraiodide, and titanium tetrachloride is preferably used among them.

The amount of titanium tetrahalide used is preferably 1 mol or more, particularly 2 to 100 mol, per 1 mol of the Grignard compound used in preparing the solid.

The solid and titanium tetrahalide can be contacted in the presence or absence of an inert organic solvent. The temperature during contact should be between 20 and 200℃, especially
The temperature is preferably 60 to 140°C. 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.

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 this invention, ethylene and an α-olefin having 3 or more carbon atoms are mixed into the α-olefin in the presence of a catalyst obtained from a solid catalyst component and an organoaluminum compound.
- Polymerization is carried out in the form of a slurry in the liquid phase of the olefin, ie under conditions in which the resulting copolymer is not substantially dissolved in the α-olefin.

Specific examples of organoaluminum compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, tri-n-hexylaluminum, and the like, among which 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.

Specific examples of α-olefins having 3 or more carbon atoms include propylene, butene-1, hexene-1,4
-Methylpentene-1, octene-1 and the like.

The copolymerization reaction is carried out under conditions in which the α-olefin remains in a liquid phase. Copolymerization temperature is 30~100℃,
In particular, the temperature is preferably 30 to 60°C, and the copolymerization pressure is at least a pressure sufficient to keep the α-olefin in a liquid phase at the copolymerization temperature, and is 100Kg/100Kg/cm considering ethylene pressure and hydrogen pressure. ^cm2 or less, especially 50
A pressure below Kg/cm ² is preferably employed.

The copolymerization 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 ethylene copolymer obtained by this copolymerization reaction contains 1 to 12% by weight of α-olefin.

There are no particular restrictions on the catalyst concentration in the copolymerization reaction system, but in general, the solid catalyst component is 0.0005 to 0.0005 titanium metal equivalent per copolymerization mixture.
10 milligram atoms per copolymerization mixture for organoalkyl aluminum compounds.
It is 0.001-1000 mmol.

Next, examples will be shown. In the following description,
"Polymerization activity" refers to the polymer yield (Kg) per 1 hour of polymerization time per 1 g of solid catalyst component used in the polymerization reaction, and "HS" refers to the produced ethylene copolymer in boiling n-hexane for 6 hours. It is the value (percentage) obtained by dividing the weight loss during extraction by the weight of the copolymer before extraction, and "MI" is the melt flow index measured at 190 °C under a load of 2.16 kg / cm ² according to ASTM D1238. It is. The butene-1 content of the ethylene copolymers was determined according to the method described in Journal of Polymer Science, 34569 (1959). In the Examples, all solid catalyst components were prepared in a dry nitrogen gas atmosphere.

Examples 1 to 7 (1) Preparation of solid catalyst components 15 mmol of anhydrous aluminum chloride and 30 mmol of toluene
Add 15 ml of methyltriethoxysilane under stirring.
10 ml of a toluene solution containing mmol was added dropwise at 25°C over 30 minutes, and the mixture was then maintained at the same temperature for 30 minutes to react.

The reaction product mixture was cooled to -6°C and, under stirring,
18 ml of diisoamyl ether containing 27 mmol of n-butylmagnesium chloride was added dropwise to the reaction mixture over 30 minutes, and the temperature was raised to 30°C over 60 minutes.
The mixture was kept at the same temperature for 60 minutes to react. The precipitated solid was separated and washed five times with 30 ml of toluene.

The solid was suspended in 30 ml of toluene, 16.5 ml of titanium tetrachloride was added to this suspension, and the solid and titanium tetrachloride were brought into contact with each other at 90° C. for 60 minutes while stirring. The solid catalyst component was separated at the same temperature, washed five times with 30 ml of n-heptane each, and then 30 ml of n-heptane was added to prepare a slurry of the solid catalyst component. The titanium content of the solid catalyst component was 5.4% by weight.

(2) Polymerization Suspension of solid catalyst component (4.1 mg as solid catalyst component) in an autoclave with internal volume of 2 equipped with a stirrer
After attaching the glass ampoule containing the autoclave, the air in the autoclave was replaced with nitrogen.

300 per gram atom of titanium in the solid catalyst component
After charging a molar amount of triethylaluminum and then 1200 ml of butene-1 into an autoclave, the temperature was raised to 50°C. Thereafter, hydrogen and then ethylene were respectively pressurized into the autoclave until the partial pressures listed in Table 1 were reached.

Start stirring to crush the glass ampoule,
Copolymerization of ethylene and butene-1 was carried out at 50°C for 1 hour.

After the copolymerization reaction is completed, unreacted monomers are released,
The produced ethylene/butene-1 copolymer was heated at 50℃ for 20
Dry under reduced pressure for an hour.

The results are shown in Table 1.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing the method for producing the ethylene copolymer of the present invention.

TABLE Examples 8 to 10 Example 1 was repeated, except that 15 mmol of the silicon compound listed in Table 2 was used instead of methyltriethoxysilane. The results are shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1 Aluminum trihalide, with the formula R ¹ _o Si(OR ² ) _4-o (wherein, R ¹ represents an alkyl group or phenyl group having 1 to 8 carbon atoms, and R ² represents a carbon The reaction product with an organosilicon compound represented by the formula R ³ MgX (wherein R ³ is an alkyl group having 1 to 8 carbon atoms and A solid catalyst component obtained by reacting a Grignard compound represented by the formula AlR ⁴ ₃ (wherein R ⁴ represents an alkyl group having 1 to 6 carbon atoms), ethylene and an α-olefin having 3 or more carbon atoms are added to the liquid phase of the α-olefin. A method for producing an ethylene copolymer, which comprises copolymerizing in a slurry form to obtain a copolymer containing 1 to 12% by weight of α-olefin.