JPH0432842B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the high temperature and high pressure polymerization of ethylene. At a temperature of 125℃ or higher and a pressure of 200Kg/cm2 ^or higher,
Methods for polymerizing ethylene in the presence of Ziegler type catalysts are known. As the above-mentioned catalyst, a combination of a titanium component, such as a titanium compound supported on a titanium trichloride and a magnesium compound, and an organoaluminum compound has been proposed (for example, Japanese Patent Laid-Open Nos. 49-97087 and 56-18607). , 57
−19009). Since all the titanium components used in the proposed method are solid, they have the following problems. The solid titanium component must be fed to the polymerization reactor maintained at high pressure as a slurry in a medium of appropriate viscosity and specific gravity. However, it is difficult to prepare a uniform slurry of titanium components, and even if a uniform slurry can be prepared, the solid titanium components tend to settle in the transport pipe, and the titanium components cannot be quantitatively transferred to the polymerization reactor. It is extremely difficult to supply. Since the amount of titanium component supplied to the polymerization reactor is not constant, the stability of the polymerization reaction is lost. In particular, if the titanium component is supplied in excess, the polymerization reaction will run out of control, resulting in an extremely dangerous situation. In the high-temperature, high-pressure polymerization of ethylene using a Ziegler-type catalyst, it is desired to develop a liquid titanium component with high catalytic activity. The present invention satisfies the above needs. That is, in the present invention, ethylene or a mixture of ethylene and an α-olefin having 3 or more carbon atoms is heated under a pressure of 200 kg/cm ² or more in the presence of a catalyst obtained from the following component [A] and component [B]. This is an ethylene polymerization method characterized by polymerization at a temperature of 125°C or higher. Component [A] Magnesium halide, a hydroxyl compound represented by the formula R ¹ OH (wherein R ¹ represents an alkyl group having 3 to 20 carbon atoms, a benzyl group, or a phenyl group), and a formula (R ² O) _n TiX ¹ _4-n (wherein, R ² represents an alkyl group having 1 to 20 carbon atoms, a benzyl group, or a phenyl group, X ¹ represents a halogen atom, and m is a number from 0 to 4). A titanium-containing solution obtained by contacting the represented titanium compound in the presence of an inert organic solvent. Component [B] Formula R ³ _o AlX ² _3-o (wherein R ³ represents an alkyl group having 1 to 8 carbon atoms, a benzyl group, or a phenyl group, X ² represents a halogen atom, and n is larger than 1) (It is a number less than 3.)
An organoaluminum compound represented by According to the present invention, the following excellent effects are achieved. (1) Since both component [A] and component [B] are liquid, they can be easily supplied to the polymerization reactor. (2) Component [A] and component [B] can be quantitatively supplied to the polymerization reactor. (3) Components for pressure fluctuations in the polymerization reactor [A]
And the supply amount of component [B] can be easily controlled. (4) Component [A] and component [B] in the polymerization reactor
Because of its good dispersion, a polymer of uniform quality can be obtained. (5) Significantly higher yields of polymer can be obtained per catalyst used. In the present invention, component [A] is prepared by nitrogen,
It is carried out under an inert gas atmosphere such as argon. Specific examples of magnesium halides include magnesium chloride, magnesium bromide, and magnesium iodide, with magnesium chloride being preferred. Specific examples of hydroxyl compounds include propanol, butanol, hexanol, octanol, 2-ethylhexanol, 2-ethylheptanol, 2-ethyloctanol, decanol,
Mention may be made of undecanol, hexadecanol, octadecanol, phenol, and benzyl alcohol. Among these, branched alkanols having 6 to 12 carbon atoms are preferably used. The amount of the hydroxyl compound used is preferably 1 to 6 moles per mole of magnesium halide. If the amount of the hydroxyl compound used is too small, it will be difficult to obtain a uniform titanium-containing solution, and if the amount used is too large, the amount of the organoaluminum compound used during polymerization will be large. Specific examples of titanium compounds include titanium tetrachloride, titanium tetrabromide, titanium tetraiodide, methoxytitanium trichloride, ethoxytitanium trichloride, butoxytitanium trichloride, octoxytitanium trichloride, dodecoxytitanium trichloride, and fluoride. Enoxytitanium trichloride, ethoxytitanium tribromide, ethoxytitanium triiodide, diethoxytitanium dichloride, dibutoxytitanium dichloride, dihexoxytitanium dichloride, triethoxytitanium chloride, tributoxytitanium chloride, trihexoxytitanium chloride, trio coxytitanium chloride,
Tetramethoxytitanium, Tetraethoxytitanium,
Tetrabutoxytitanium and tetraoctoxytitanium are mentioned. Among these, tetraalkoxytitanium and alkoxytitanium chloride are preferably used. The amount of the titanium compound used is preferably 0.005 to 1 mol, particularly 0.01 to 0.5 mol, per 1 mol of magnesium halide. Specific examples of inert organic solvents include hexane,
Examples include aliphatic hydrocarbons such as heptane and higher alkanes, aromatic hydrocarbons such as benzene, toluene, and xylene, and halides thereof. There is no particular restriction on the amount of inert organic solvent used, but it is usually
It is between 0.5 and 20. magnesium halide, hydroxyl compound,
There is no particular restriction on the method of contacting the titanium compound with the titanium compound. For example, magnesium halide,
A method of adding a hydroxyl compound to a mixture of a titanium compound and an inert organic solvent, a method of adding a hydroxyl compound and then a titanium compound to a slurry of magnesium halide in an inert organic solvent, a method of adding a hydroxyl compound and a titanium compound to the above slurry simultaneously. Can be adopted. The contact temperature is usually 0 to 200°C, and the contact time is usually 5 minutes or more. Specific examples of organoaluminum compounds (component [B]) include diethylaluminum chloride,
Dibutylaluminum chloride, dihexylaluminum chloride, diethylaluminum bromide, diethylaluminum iodide, diphenylaluminum chloride, dibenzylaluminum chloride, ethylaluminum sesquichloride, butylaluminum sesquichloride, and phenylaluminum sesquichloride. The amount of organoaluminum compound used is usually 1 to 1 per gram atom of titanium in the titanium-containing solution.
It is 1000 moles. In the present invention, component [A] and component [B]
An ethylene homopolymer or an ethylene copolymer is obtained 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 . Specific examples of α-olefins having 3 or more carbon atoms include propylene, butene-1,4-methylpentene-1, and octene-1. Polymerization pressure is 200Kg/ ^cm2 or more, preferably 500~
It is 3000Kg/ ^cm2 . The polymerization temperature is 125°C or higher, preferably 150-350°C. The average residence time of the monomer in the polymerization system is 2 to 600 seconds, preferably 10 to 150 seconds.
Seconds. As the polymerization apparatus, a tubular reactor or a tank reactor can be used. The molecular weight of the polyethylene produced can be easily controlled by adding a molecular weight regulator, such as hydrogen, to the polymerization system. Next, examples will be shown. In the examples, "polymerization activity" refers to 1 g of titanium in the component [A] used.
It means the yield of polyethylene per unit (Kg), "M.
190 under a load of 2.16Kg according to ASTMD1238.
Melt index of polyethylene measured in °C. Example 1 (1) Preparation of titanium-containing solution (component [A]) Anhydrous magnesium chloride in n-heptane 12
10.8 mol and tetra-n-butoxytitanium 1.5
Added moles. The resulting suspension was added with 2-
After adding 45.2 moles of ethylhexanol, 90℃
The mixture was heated to 100% and stirred at the same temperature for 3 hours to obtain a uniform titanium-containing solution. Add this solution to Cielsol
71 (manufactured by Ciel Chemical Co., Ltd.) and diluted with 148 to obtain component [A]. The titanium concentration in component [A] is
It was 9 milligram atom/atom. (2) Polymerization In a reaction tube with a total length of approximately 400 m, 64% by weight of ethylene,
Ethylene and butene-1 were copolymerized under a pressure of 2000 kg/cm ² by continuously supplying a monomer consisting of 36% by weight of butene-1 and 0.2 VO% of hydrogen to the monomer. Cielsol 71 solution (concentration: 450 mmol/) of diethylaluminum chloride as the above component [A] and component [B], respectively,
The reaction tube was fed continuously at a rate of 3.5/hour through an injection point provided at the inlet. The temperature inside the reaction tube was maintained at 140°C at the inlet and 250°C at the maximum temperature. The flow rate of the monomer in the reaction tube was 10 m/sec. The above continuous operation was carried out for 3 hours. MI5.1
An ethylene/butene-1 copolymer with a density of 0.925 g/cm ³ and a polymerization activity of 510 was obtained. Examples 2 and 3 Example 1 was repeated except that the amount of 2-ethylhexanol used was varied as described in Table 1. The results are shown in Table 1.

Table: Examples 4 and 5 Example 1 was repeated, except that 45.2 mol of the alkanol listed in Table 2 was used instead of 2-ethylhexal. The results are shown in Table 2.

[Table] Nord 5 2〓Ethyl octa 5.4 0.928 510
Knoll
Examples 6 and 7 Example 1 except that 1.5 mol of the compound listed in Table 3 was used instead of tetra-n-butoxytitanium.
repeated. The results are shown in Table 3.

[Table] Tanchloride 7 Titanium tetrac 5.8 0.926 380
loride

[Brief explanation of drawings]

FIG. 1 shows a flow chart for catalyst preparation of the present invention.

Claims (1)

[Claims] 1. Ethylene or ethylene and α- having 3 or more carbon atoms
A mixture with olefin was added at 200 kg/kg in the presence of a catalyst obtained from component [A] and component [B] below.
A method for polymerizing ethylene, characterized by polymerization at a temperature of 125°C or higher under a pressure of ² cm2 or higher. Component [A] Magnesium halide, a hydroxyl compound represented by the formula R ¹ OH (wherein R ¹ represents an alkyl group having 3 to 20 carbon atoms, a benzyl group, or a phenyl group), and a formula (R ² O) _n TiX ¹ _4-n (wherein, R ² represents an alkyl group having 1 to 20 carbon atoms, a benzyl group, or a phenyl group, X ¹ represents a halogen atom, and m is a number from 0 to 4). A titanium-containing solution obtained by contacting the represented titanium compound in the presence of an inert organic solvent. Component [B] Formula R ³ _o AlX ² _3-o (wherein R ³ represents an alkyl group having 1 to 8 carbon atoms, a benzyl group, or a phenyl group, X ² represents a halogen atom, and n is larger than 1) (It is a number less than or equal to 2.)
An organoaluminum compound represented by