JP2509281B2 - Method for producing ethylene-based polymer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an ethylene-based polymer, and more particularly, to the efficiency of an ethylene-based polymer including linear low density polyethylene by high temperature solution polymerization. Regarding a good manufacturing method.

[Problems to be Solved by Prior Art and Invention]

Conventionally, as a method for producing linear low density polyethylene, a high pressure ionic method, a gas phase polymerization method, a suspension polymerization method, and a high temperature solution polymerization method have been known. Among these methods, the high-pressure ion method and the gas phase polymerization method have a difficulty in using a higher α-olefin, and the suspension polymerization method has a problem in producing a low density product. Therefore, higher α such as octene-1 is used as a comonomer.
Considering that the strength of the linear low density polyethylene is improved by using the olefin, it can be said that the high temperature solution polymerization method is excellent as a method for producing the linear low density polyethylene.

Further, a polymer having a low density is desired from the viewpoints of flexibility and transparency of the polymer, but the molecular weight distribution of the polymer tends to widen with the decrease in the density. However, this tendency adversely affects the strength and transparency of the polymer.

Generally, in the solution polymerization method, since the produced polymer is dissolved in a solvent and the liquid viscosity in the polymerization system increases, it is desirable to carry out the polymerization at a temperature as high as possible (155 ° C. or higher) in the operation of the apparatus. However, all of the catalysts used in the conventionally known methods have insufficient activity at high temperatures, and the physical properties of the copolymers obtained by high temperature solution polymerization so far are not yet satisfactory.

A supported catalyst has been developed as a catalyst for high-temperature solution polymerization to improve activity (see Japanese Patent Publication No. 59-52643), but its manufacturing process is complicated, and an unnecessary titanium component is prepared from the prepared catalyst. In most cases, a cleaning step was required to remove the slag. Therefore, a catalyst manufacturing facility is required and a large amount of cleaning solvent is required.

Some proposals have hitherto been made for the purpose of easily obtaining a catalyst having high activity at high temperature. Japanese Patent Publication Nos. 46-31968 and 50-39117, among which, report catalyst systems that can achieve relatively high activity without preparing a catalyst in advance. However, in any of these cases, none of them can express a sufficiently high activity, which causes a new defect such as a change in hue of the produced polymer.

JP-A-60-42405 proposes to use alcohol as an activator in order to improve the activity, but the addition of alcohol alone does not exert a sufficient effect.

Further, JP-A-58-120609 discloses a catalyst using two kinds of transition metals, titanium and zirconium, but since the preparation procedure and the like have not been sufficiently devised, the molecular weight distribution is narrow. No polymer can be obtained.

Therefore, the present inventor has developed a catalyst system which has a sufficiently high activity even at high temperature, does not require a complicated preparation step, and further does not need to wash and remove the residual components in the produced polymer,
Furthermore, we have conducted intensive studies to develop a method for efficiently producing an ethylene-based polymer including a linear low-density ethylene-based polymer having a narrow molecular weight distribution and excellent physical properties using the catalyst system. .

[Means for solving the problem]

As a result, as a catalyst for high temperature solution polymerization, a reaction product of an organomagnesium compound and an organoaluminum compound and a catalyst containing a specific zirconium compound as a main component were used together with a specific titanium compound, and the produced polymer was dissolved in the reaction medium. It has been found that the above problems can be solved by carrying out the polymerization under the heating conditions. The present invention has been completed based on such findings.

That is, in the present invention, when ethylene is homopolymerized or copolymerized with another α-olefin in the presence of a catalyst in a reaction medium to produce an ethylene-based polymer, (A) the general formula Ti (OR ¹ ) _n X ¹ _4-n ...... [I] [In the formula, R ¹ is an alkyl group having 1 to 18 carbon atoms, 6 to 18 carbon atoms
Represents a cycloalkyl group or an aryl group having 6 to 18 carbon atoms, and X ¹ represents a halogen atom. In addition, n is 0 ≦ n ≦ 4
Is a real number that satisfies. ] (B) (a) General formula MgR ² R ³ ... [II] [wherein R ² is an alkyl group having 1 to 18 carbon atoms or 6 carbon atoms]
To 18 aryl groups, R ³ represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a halogen atom. ] An organomagnesium compound represented by the formula (b) and a general formula R ⁴ _m AlX ² _3-m [III] [wherein R ⁴ is an alkyl group having 1 to 20 carbon atoms, and 6 to 20 carbon atoms]
Represents an aryl group, an alkoxy group having 1 to 20 carbon atoms or an aryloxy group having 6 to 20 carbon atoms, and X ² represents a halogen atom. Further, m is a real number that satisfies 0 <m ≦ 3. When m is plural, each R ⁴ may be the same or different. ] The reaction product of an organoaluminum compound represented by the formula (C) and the general formula Zr (OR ⁵ ) _k X ³ _4-k ...... [IV] [wherein R ⁵ is an alkyl group having 1 to 20 carbon atoms, carbon Number 6 to 20
Represents a cycloalkyl group, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and X ³ represents a halogen atom. Further, k is a real number that satisfies 0 ≦ k ≦ 4. ] A method for producing an ethylene-based polymer is provided, which comprises using a catalyst containing a zirconium compound represented by the following as a main component, and carrying out polymerization or copolymerization under heating conditions in which a produced polymer is dissolved in a reaction medium. It is a thing.

In the method of the present invention, the above-mentioned (A),
Polymerization is carried out using a catalyst containing the components (B) and (C) as the main components, but the transition metal component (A) has the general formula Ti (O
R ¹ ) _n X ¹ _4-n ... [I] [In the formula, R ¹ , X ¹ and n are the same as defined above. ] The titanium compound represented by is contained. Here, in the titanium compound represented by the general formula [I], when n is 0, the general formula TiX ¹ ₄ [wherein, X ¹ is the same as the above. ] A titanium tetrahalide represented by the following, specifically, for example, TiCl ₄ , TiBr ₄ , and TiI ₄ , and when n is 1, a general formula Ti (OR ¹ ) X ¹ ₃ [in the formula, R ¹ And X ¹ are the same as above. ] The titanium compound represented by
₃ O) TiCl ₃ , (C ₂ H ₅ O) TiCl ₃ , (C ₃ H ₇ O) TiCl ₃ , (n-C ₄ H ₉
O) TiCl ₃ or the like or a corresponding trihalogenated alkoxytitanium in which X ¹ is bromine or iodine, or a trihalogenated cycloalkyloxytitanium such as trichlorocyclohexoxytitanium or a trihalogenated aryloxytitanium such as trichlorophenoxytitanium. , N is 2
In the formula, Ti (OR ¹ ) ₂ X ¹ ₂ [wherein R ¹ and X ¹ are the same as defined above. ] A titanium compound represented by, for example, (CH ₃ O) ₂ TiCl ₂ , (C ₂ H ₅ O) ₂ TiC
l ₂ , (C ₃ H ₇ O) ₂ TiCl ₂ , (n-C ₄ H ₉ O) ₂ TiCl ₂ etc. or X ¹
Is a corresponding dihalogenated dialkoxytitanium such as bromine or iodine, or a dihalogenated dicycloalkyloxytitanium such as dichlorodicyclohexoxytitanium, or a dihalogenated diaryloxytitanium such as dichlorodiphenoxytitanium, wherein n is 3. Is the general formula
Ti (OR ¹ ) ₃ X ¹ [In the formula, R ¹ and X ¹ are the same as defined above. ] A titanium compound represented by, for example, (CH
₃ O) ₃ TiCl, (C ₂ H ₅ O) ₃ TiCl, (C ₃ H ₇ O) ₃ TiCl, (n-C ₄ H ₉
O) ₃ TiCl etc. or the corresponding monohalogenated trialkoxytitanium in which X ¹ is bromine or iodine, or monohalogenated tricycloalkyloxytitanium such as monochlorotricyclohexoxytitanium or monohalogenated tria such as monochlorotriphenoxytitanium. When it is reel oxytitanium and n is 4, the general formula Ti (O
R ¹ ) ₄ [in the formula, R ¹ is the same as the above], specifically, for example, tetramethoxy titanium, tetraethoxy titanium, tetra-n-propoxy titanium, tetraisopropoxy titanium, tetra- Examples thereof include tetraalkoxytitanium such as n-butoxytitanium and tetraisobutoxytitanium, tetracycloalkyloxytitanium such as tetracyclohexoxytitanium, and tetraaryloxytitanium such as tetraphenoxytitanium. Of these, the above general formula Ti (OR ¹ )
_The tetraalkoxy titanium represented by ₄ and the titanium tetrahalide represented by TiX ₄ are preferable, and tetra-n-butoxy titanium and tetrachloro titanium are particularly preferable. These various titanium compounds may be used alone or in combination of two or more.

In the catalyst used in the method of the present invention, the component (B) is the reaction product of the components (a) and (b) as described above.
Here, the component (a) is represented by the general formula MgR ² R ³ ... [II] [wherein, R ² and R ³ are the same as described above. ] An organomagnesium compound represented by, for example, dialkyl magnesium such as diethyl magnesium, dibutyl magnesium, butyl octyl magnesium, diamyl magnesium, dihexyl magnesium, dioctyl magnesium, ethyl butyl magnesium, butyl isopropyl magnesium, diphenyl magnesium, etc. Alkyl aryl magnesium such as diaryl magnesium, ethyl phenyl magnesium, etc., alkyl magnesium alkoxides such as butyl magnesium isopropoxide, aryl magnesium alkoxides such as phenyl magnesium propoxide, alkyl magnesium halides such as butyl magnesium chloride, amyl magnesium chloride, phenyl magnesium chloride Aryl etc. Magnesium halide and the like can be mentioned. Of these, dibutyl magnesium, dihexyl magnesium, butyl octyl magnesium and the like are particularly preferable. Even if the organomagnesium compound is used alone,
Also, two or more of the above may be mixed and used.

The component (b) is represented by the general formula R ⁴ _m AlX ² _3-m ... [III] [wherein, R ⁴ , X ² and m are the same as defined above. ] An organoaluminum compound represented by, for example, the general formula R ⁴ ₃ Al, R ⁴ ₂ AlX ² , R ⁴ AlX ² ₂ , R ⁴ ₂ AlOR ⁶ , R ⁴ Al (OR ⁶ ) X ² ,
(OR ⁶ ) ₃ Al (wherein R ⁶ represents an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms) or a compound represented by the general formula R ⁴ ₃ Al ₂ X ² ₃ To be More specifically, these compounds include triethyl aluminum, tripropyl aluminum, tributyl aluminum, triamyl aluminum, trioctyl aluminum, diethyl aluminum monochloride, dipropyl aluminum monochloride, diisopropyl aluminum monochloride, diisobutyl aluminum monochloride, Dioctyl aluminum monochloride, ethyl aluminum dichloride, isopropyl aluminum dichloride, butyl aluminum dichloride, octyl aluminum dichloride, aluminum triethoxide, aluminum triisopropoxide, aluminum triisobutoxide, diethyl aluminum monoethoxide, dipropyl aluminum monoethoxide, Monoethyl monoethoxy al Niumukurorido, monoethyl-isopropoxy aluminum chloride, ethyl aluminum sesquichloride, propyl aluminum sesquichloride,
Butyl aluminum sesquichloride and the like. Among these organic aluminum compounds, for example, diethyl aluminum monochloride, diisopropyl aluminum monochloride, diisobutyl aluminum monochloride, dioctyl aluminum monochloride, ethyl aluminum dichloride, isopropyl aluminum dichloride,
Ethyl aluminum sesquichloride and the like are preferable, and in particular, compounds represented by the general formula R ⁴ ₂ AlX ² such as diethyl aluminum monochloride and compounds represented by the general formula R ⁴ ₃ Al ₂ X ² ₃ such as ethyl aluminum sesquichloride are preferable. .

In the method of the present invention, it is necessary to use the reaction product of the component (a) and the component (b) as described above as the component (B) of the catalyst, and these components (a) and (b) are used in the polymerization. Even if they are separately added to the polymerization reaction system, sufficient catalytic activity cannot be obtained.

Further, the catalyst used in the method of the present invention is (A),
(B) is composed mainly of components as well as the component (C), as the component (C), the general formula Zr (OR ⁵⁾ _k X ³ in _4-k ...... [IV] [wherein, R ^5, X ³ and k are the same as above. ] A zirconium compound represented by the following is used. Specifically, tetramethoxyzirconium, tetraethoxyzirconium, tetra (n-propoxy) zirconium, tetra (i-propoxy) zirconium, tetra (n-butoxy) zirconium, tetra (n-pentoxy) zirconium, tetra (n-hexoxy). General formulas such as zirconium, tetra (n-heptoxy) zirconium, tetra (n-octoxy) zirconium, tetra (2-ethylhexoxy) zirconium, tetracyclohexoxyzirconium, and tetraphenoxyzirconium Zr (OR
⁵ ) In addition to tetraalkoxyzirconium represented by ₄ , triethoxyzirconium chloride, tri (i-
Propoxy) zirconium chloride, tri (t-butoxy) zirconium chloride, diethoxyzirconium dichloride, di (n-propoxy) zirconium dichloride, di (i-propoxy) zirconium dichloride, di (n-butoxy) zirconium dichloride, diethoxyzirconium bromide , Di (n-butoxy) zirconium bromide, zirconium tetrachloride, zirconium tetrabromide and the like. Of these, the general formula Zr (OR ⁵ )
Tetraalkoxyzirconium represented by ₄ is preferable, and tetraethoxyzirconium, tetra (i-propoxy) zirconium, and tetra (n-butoxy) zirconium are most preferable.

The catalyst used in the method of the present invention is (A) as described above,
Although the components (B) and (C) are the main components, an electron donating compound can be used as the component (D) or as a part of the component (B). Here, there are various kinds of electron-donating compounds, for example, oxygen-containing compounds such as alcohols, ethers, aldehydes, ketones, carboxylic acids and their esters, nitrogen-containing compounds such as amines and imines, or silicon-containing compounds. is there. this house,
As alcohol, ethanol, n-propanol, i-
Propanol, n-butanol, i-butanol, t-butanol, n-hexanol, 2-ethylhexanol, n-octanol, n-decanol, oleyl alcohol, stearyl alcohol and other aliphatic alcohols, cyclopentanol, cyclohexanol, etc. Examples thereof include alicyclic alcohols, aromatic alcohols such as benzyl alcohol and methylbenzyl alcohol, and aliphatic alcohols containing an alkoxyl group in n-butyl cellosolve.

Further, as ether, diethyl ether, di-n
-Propyl ether, di-i-propyl ether, di-
n-butyl ether, di-n-amyl ether, di-i
-Amyl ether, dineopentyl ether, di-n-
Hexyl ether, di-n-octyl ether, methyl-n-butyl ether, methyl-t-butyl ether,
Examples thereof include aliphatic chain ethers such as methyl-i-amino ether, ethyl-i-butyl ether and ethyl-n-butyl ether, aromatic chain ethers such as anisole and phenetole, and cyclic ethers such as tetrahydrofuran.

Aldehydes include benzartehde, butyraldehyde, acrylaldehyde, 2-ethylhexylaldehyde, decylaldehyde and undecylaldehyde, and examples of ketones include acetone, methylethylketone, acetophenone, benzophenone and cyclohexanone.

Carboxylic acids include benzoic acid, caprylic acid, oleic acid, lauric acid, stearic acid and the like, and carboxylic acid esters include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl and decyl of the above carboxylic acids. Further, esters of formic acid, acetic acid, propionic acid, butyric acid, toluic acid methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, decyl, etc., or phthalic acid methyl, ethyl, propyl, butyl, pentyl, Diesters such as hexyl, octyl and decyl can be mentioned.

The above is an oxygen-containing compound among the electron-donating compounds. Next, as a nitrogen-containing compound, propylamine, pentylamine, heptylamine, octylamine, 2-ethylhexylamine, decylamine, laurylamine, dibutylamine, dioctylamine. , Benzylamine, toluylamine, and other amines, and aniline.

Examples of the silicon-containing compound include trimethylmethoxysilane, trimethylethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane ethyl silicate, propyl silicate, butyl silicate and the like. .

Of these electron-donating compounds, alcohols or ethers are preferable, and specifically n-octanol, 2
-Ethylhexanol, n-decanol, oleyl alcohol, stearyl alcohol, anisole, methyl-t
-Butyl ether can be mentioned as a preferable example, and stearyl alcohol and methyl t-butyl ether are particularly preferable.

In the catalyst used in the present invention, the electron donating compound is not an essential component, but when this electron donating compound is used as one component of the catalyst, a narrow molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) is maintained. However, it becomes possible to produce a lower density ethylene polymer.

The electron-donating compound may be added to the polymerization reaction system as the component (D) separately from the components (A), (B) and (C), or it is the component (B). It can also be used as one component of the reaction product when the reaction product of the component and the component (b) is prepared or added after the preparation. Among them, the use as a component of the reaction product which is the component (B) is more effective in improving the activity of the catalyst or obtaining an ethylene polymer having a narrow molecular weight distribution.

In the method of the present invention, the mixing order of the components of the catalyst is not particularly limited, and for example, the components (a) and (b) (or further electron donating compounds) are added to the polymerization reaction system and reacted (B). ) After obtaining the reaction product of the component,
The components (A) and (C) (or further the electron-donating compound as the component (D)) are separately or mixed,
It may be introduced into the polymerization reaction system at the same time as or before or after the reaction raw material ethylene or other α-olefin. Alternatively, the components (A) and (C) may be introduced into the polymerization reaction system first, and then the component (B) prepared separately may be introduced. However, before reacting the components (a) and (b),
Even if the components (A) and (B) are added to these, sufficient catalytic activity cannot be obtained.

Further, the mixing ratio of each component of the catalyst used in the method of the present invention may be appropriately determined depending on various situations. Usually, (a) the organomagnesium compound is added to (a) the titanium compound described above. / (A) (atomic ratio of Mg / Ti) = 0.1 to 30,
It is preferably 0.5 to 20. If it is out of this range, the catalytic activity tends to be lowered. Regarding the (b) organoaluminum compound, (b) / (A) (atomic ratio of Al / Ti) = 1 to 120, preferably 5 to 80. When the atomic ratio of Al / Ti is less than 1, the activity of the catalyst is low, and even when it exceeds 120, the activity corresponding to the added amount is not improved. Further, when the amount is out of the above range, the physical properties of the obtained ethylene polymer, particularly the film moldability, are deteriorated. Also (C)
For zirconium compounds, (A) / (C) (Ti / Z
(atomic ratio of r) = 0.1 to 10, preferably 0.2 to 5. If this ratio is too small, the activity tends to decrease,
When it exceeds 10, the effect of adding the zirconium compound is not sufficiently exhibited. Further, regarding the electron donating compound, the electron donating compound / (A) titanium compound (molar ratio of each compound) = 0.1 to 200, preferably 0.2 to 100.

The component (A), (B), (C), or the catalyst containing the component (D) as a main component together therewith, may be used as a solution by using an inert catalyst, if necessary. Examples of the inert solvent that can be used include aliphatic hydrocarbons having 5 to 18 carbon atoms, alicyclic hydrocarbons, aromatic hydrocarbons, and the like. Specifically, n- or i-pentane, hexane,
Examples include heptane, octane, nonane, decane, tetradecane or cyclohexane, and further benzene, toluene, xylene and the like. Also, as this inert solvent,
The various hydrocarbons mentioned above can be used alone.
Among these, preferable inert solvents include, for example, n-
Hexane can be mentioned.

There are various procedures for carrying out the process of the present invention, but generally, the (A), (B) and (C) components (and also the (D) component) are introduced separately into the reactor. Or, after mixing and preparing in advance, the mixture is introduced into a reactor, and then ethylene and, if necessary, α-olefin are supplied to start the polymerization.

In the present invention, the monomer may be ethylene alone,
Other α-olefins may be used as comonomers.
Examples of the α-olefin include linear or branched monoolefin having 3 to 18 carbon atoms or α-olefin substituted with an aromatic nucleus. Specific examples of the α-olefin that can be used include linear monoolefins such as propylene, butene-1, hexene-1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, 3 -Methylbutene-1; 3-methylpentene-1; 4-methylpentene-
It is a branched chain monoolefin such as 1; 2-ethylhexene-1; 2,2,4-trimethyl-pentene-1 or a monoolefin substituted with an aromatic nucleus such as styrene.

The polymerization reaction is carried out in a reaction medium, and can be carried out continuously or batchwise under heating conditions (that is, high temperature solution polymerization) under which the produced polymer is dissolved in the reaction medium. As the reaction medium, an inert solvent such as the above-mentioned aliphatic hydrocarbon, alicyclic hydrocarbon or aromatic hydrocarbon can be used. The reaction temperature is a temperature at which the produced polymer is dissolved in the reaction medium, usually 140 ° C.
Above, in particular, 180 to 220 ° C., that is, the liquid viscosity of the produced polymer solution is lowered to a temperature preferable for operating the apparatus.

Other polymerization conditions cannot be uniquely determined depending on the physical properties of the desired polymer, the types of monomers used, etc.,
Usually, the catalyst concentration is 0.001-10 mmol / titanium concentration /
, Preferably 0.01-1.0 mmol / m. Also,
The reaction pressure is usually 10 to 150 kg / m ² , and preferably 20 to 70 kg / m ² . A molecular weight modifier such as hydrogen or diethyl zinc may be present in the polymerization reaction system.

〔Example〕

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1 After thoroughly replacing the inside of the dried polymerization reactor with a stirrer 1 with argon, 400 ml of dried n-hexane and 1-
100 ml of octene was charged and the temperature was raised to 185 ° C.

Next, 3.75 ml of n-hexane solution of ethylaluminum sesquichloride (0.25 mol /) and 2.3 ml of n-hexane solution of dihexylmagnesium (0.1 mol /) were placed in this order in a catalyst preparation vessel and mixed to react at room temperature. Then, tetra (n-butoxy) prepared in advance
A mixed solution of titanium n-hexane solution (0.025 mol /) 1.9 ml and tetra (n-butoxy) zirconium n-hexane solution (0.025 mol /) 1.9 ml was added and mixed, and then mixed with ethylene gas in a polymerization reactor. Introduced, total pressure 40kg / c
Polymerization was carried out at 185 ° C for 5 minutes while maintaining m ² G and ethylene-
84.2 g of 1-octene copolymer was obtained. The properties of this copolymer are shown in Table 1.

Example 2 The amount of tetra (n-butoxy) zirconium added was 0.94.
Copolymerization was performed in the same manner as in Example 1 except that the amount was changed to ml to obtain 99.3 g of an ethylene-1-octene copolymer.
The properties of this copolymer are shown in Table 1.

Example 3 Copolymerization in the same manner as in Example 1 except that 1.9 ml of a solution of tetra (i-propoxy) zirconium in n-hexane (0.025 mol /) was added instead of tetra (n-butoxy) zirconium. Then, 80.6 g of an ethylene-1-octene copolymer was obtained. The properties of this copolymer are shown in Table 1.

Example 4 After thoroughly replacing the inside of the dried polymerization reactor with a stirrer 1 with argon, 400 ml of dried n-hexane and 1-
100 ml of octene was charged and the temperature was raised to 185 ° C.

Next, 3.5 ml of n-hexane solution of methyl-t-butyl ether (0.1 mol /), 3.75 ml of n-hexane solution of ethyl aluminum sesquichloride (0.25 mol /),
2.3 ml of n-hexane solution (0.1 mol /) of dihexylmagnesium was put into the catalyst preparation device in this order and mixed,
After reacting at room temperature, 1.9 ml of tetra- (n-butoxy) titanium n-hexane solution (0.025 mol /) and tetra- (n-butoxy) zirconium n-hexane solution (0.025 mol /) prepared beforehand 1.9 ml of mixed solution was added and mixed, and then introduced into a polymerization reactor at the same time as ethylene gas, and polymerization was carried out at 180 ° C for 5 minutes while keeping the total pressure at 40 kg / cm ² G to obtain ethylene-1-octene copolymer. 89.4g was obtained. The properties of this copolymer are shown in Table 1.

Example 5 5.6 ml of a solution of stearyl alcohol in n-hexane (0.05 mol /) was used instead of methyl-t-butyl ether.
Polymerization was carried out in the same manner as in Example 4 except that the ethylene-1-octene copolymer was obtained, yielding 99.3 g. The properties of this copolymer are shown in Table 1.

Comparative Example 1 Polymerization was performed in the same manner as in Example 1 except that the zirconium compound was not used, to obtain 84.4 g of an ethylene-1-octene copolymer. The properties of this copolymer are
Shown in the table.

Comparative Example 2 Polymerization was carried out in the same manner as in Example 5 except that the zirconium compound was not used, to obtain 122.1 g of an ethylene-1-octene copolymer. The properties of this copolymer are
Shown in the table.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 1 except that the same amount of the catalyst component as in Example 1 was used and the addition order was changed. That is, ethyl aluminum sesquichloride,
Adopting a method in which tetra (n-butkin) zirconium, tetra (n-butkin) titanium, and dihexylmagnesium are added in this order to form a catalyst, and then charged into a polymerization reactor, ethylene-1-octene copolymer 72.6 g Got The properties of this copolymer are shown in Table 1.

As can be seen from the results in Table 1, in Comparative Example 3,
The catalytic activity is lower than in Example 1, and the molecular weight distribution is broad. From this, it is understood that in order to efficiently produce a polymer having a narrow molecular weight distribution, it is necessary to add a transition metal compound after the magnesium compound and the organoaluminum compound are catalytically reacted.

[Effect of the Invention] According to the method of the present invention, various ethylene polymers can be efficiently produced. In particular, a high-quality linear low-density ethylene polymer having a narrow molecular weight distribution can be efficiently produced at a high temperature with a small amount of comonomer, and a high polymer yield can be achieved. Further, the catalyst used in the method of the present invention has a high activity, and it is not necessary to increase the addition amount for improving the activity, and the residual amount of the catalyst in the polymer can be remarkably reduced. Therefore, a high quality polymer (copolymer) can be obtained without performing deashing treatment.

[Brief description of drawings]

FIG. 1 is a flow chart illustrating the method of the present invention.

Claims (3)

(57) [Claims] 1. In producing an ethylene polymer by homopolymerizing ethylene or copolymerizing ethylene with another α-olefin in the reaction medium in the presence of a catalyst, (A) a general formula Ti (OR ¹ ) _n X ¹ _4-n [wherein R ¹ is an alkyl group having 1 to 18 carbon atoms, 6 to 18 carbon atoms]
Represents a cycloalkyl group or an aryl group having 6 to 18 carbon atoms, and X ¹ represents a halogen atom. In addition, n is 0 ≦ n ≦ 4
Is a real number that satisfies. ] (B) (a) General formula MgR ² R ³ [wherein R ² is an alkyl group having 1 to 18 carbon atoms or 6 carbon atoms]
To 18 aryl groups, R ³ represents an alkyl group having 1 to 18 carbon atoms, an alkoxy group having 1 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, or a halogen atom. And (b) a general formula R ⁴ _m AlX ² _3-m [wherein R ⁴ is an alkyl group having 1 to 20 carbon atoms, and 6 to 20 carbon atoms]
Represents an aryl group, an alkoxy group having 1 to 20 carbon atoms or an aryloxy group having 6 to 20 carbon atoms, and X ² represents a halogen atom. Further, m is a real number that satisfies 0 <m ≦ 3. When m is plural, each R ⁴ may be the same or different. ] The reaction product of the organoaluminum compound represented by the formula (C) and the general formula Zr (OR ⁵ ) _k X ³ _4-k [wherein R ⁵ is an alkyl group having 1 to 20 carbon atoms, and 6 to 20 carbon atoms]
Represents a cycloalkyl group, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms, and X ³ represents a halogen atom. Further, k is a real number that satisfies 0 ≦ k ≦ 4. ] The method for producing an ethylene-based polymer, which comprises using a catalyst containing a zirconium compound represented by the following as a main component and carrying out polymerization or copolymerization under heating conditions such that the produced polymer is dissolved in a reaction medium. 2. A catalyst comprising a titanium compound according to claim 1, a reaction product of (B) an organomagnesium compound and an organoaluminum compound, (C) a zirconium compound and (D) an electron donating compound as a main component. The method for producing an ethylene-based polymer according to claim 1, wherein 3. The ethylene-based polymer according to claim 1, wherein the component (B) of the catalyst is a reaction product of the (a) organomagnesium compound, (b) organoaluminum compound and electron donating compound according to claim 1. Manufacturing method of coalescence.