JPH083226A - Method for producing ethylene / α-olefin copolymer - Google Patents

Abstract

(57) [Summary] [Purpose] The removal of impurities prevents the metallocene catalyst from deteriorating in activity. In the method for producing an ethylene / α-olefin copolymer in which ethylene and an α-olefin having 3 or more carbon atoms are copolymerized with a metallocene catalyst under conditions of high temperature and high pressure, unreacted gas after the polymerization reaction is fixed bed. A method for producing, characterized by passing through a adsorption tower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the removal of impurities in the system which are catalyst poisons in the production of ethylene / α-olefin copolymers using metallocene catalysts.

[0002]

2. Description of the Related Art Conventionally, in the production of ethylene / α-olefin copolymers using a Ziegler type catalyst, impurities (reaction terminator, blocking agent,
Removal of catalyst decomposition products, etc.) was generally performed by a separator in the recycling process.

However, in the production of ethylene / α-olefin copolymers using a metallocene-based highly active catalyst, since the catalyst is highly active, conventional Ziegler-based catalysts do not adversely affect the activity. Even with the amount of impurities, there is a problem that the activity is affected.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the activity of the metallocene catalyst from being lowered by removing impurities more than the conventional method.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have newly provided an apparatus equipped with an adsorbent and passed an unreacted gas through it. The inventors have found that an ethylene / α-olefin copolymer can be produced by a metallocene catalyst without lowering the catalytic activity, and completed the present invention. Hereinafter, the present invention will be described in detail.

A high temperature and high pressure method will be described as a method for producing an ethylene / α-olefin copolymer by a metallocene catalyst.

FIG. 1 is a schematic diagram of ethylene / ethylene copolymerized with ethylene and an α-olefin having 3 or more carbon atoms by a high temperature / high pressure method
1 shows an outline of a manufacturing process of an α-olefin copolymer. The raw materials ethylene and α-olefin are supplied from respective supply lines 1 and 2 and boosted to a predetermined polymerization pressure by compressors 3 and 4, while the catalyst is supplied by a catalyst injection pump 5. Then, polymerization is carried out in the reactor while stirring with a stirrer, and a reaction terminator is injected from the reactor outlet 6 in order to prevent further reaction. The reaction pressure in the reactor is controlled by the pressure control valve 7, and the reaction temperature is controlled by the injection amount of the catalyst. The ethylene / α-olefin copolymer polymerized in the reactor and the unreacted gas are separated by the high pressure separator 8, and the unreacted gas is compressed through the heat exchangers 9 and 11 and the separators 10 and 12 in the high pressure recycling process. Returned to vessel 2. On the other hand, the ethylene / α-olefin copolymer separated from the high-pressure separator is sent to the low-pressure separator 13, where ethylene / α-olefin copolymer is further added.
The unreacted gas dissolved in the α-olefin copolymer and the ethylene / α-olefin copolymer are separated, and the unreacted gas passes through the heat exchanger 14 and the separator 15 in the low pressure recycling process, and then the low pressure compressor 16 It is re-compressed at 1, then passed through the separator 17, and then returned to the compressor 1. On the other hand, the separated ethylene / α-olefin copolymer is extracted by the extruder 18 below the low pressure separator 13. As the reaction conditions, the reaction temperature is preferably 120 to 300 ° C., the reaction pressure is 400 to 4000 kg / cm ² , and preferably 500 to
It is 2000 kg / cm ² . Further, the operating conditions of the recycling process are preferably pressure of 30 to 260 kg / cm ² and temperature of 150 to 250 ° C.

The impurity removing apparatus used in the present invention is shown in FIG.
It is installed between the separator and the compressor in the middle recycling process, and the operating condition is a pressure of 30 to 260 kg / cm ² ,
The temperature is preferably 60 ° C. or lower. The reason for this is that it is more advantageous to remove impurities at a low temperature, and by installing it after the separator, avoiding clogging by ethylene / α-olefin copolymer, wax, etc. that are entrained and scattered in the unreacted gas. Because you can.

The impurity removing device described here is a so-called fixed bed adsorption tower in which a pressure vessel is filled with an adsorbent described below, and its outline is shown in FIG. The unreacted gas after the polymerization reaction is introduced from the tower bottom inlet 1, adsorbs impurities in the unreacted gas in the adsorption layer 2, and then returned from the tower top outlet 3 to the suction side of the compressor.

As a component of the metallocene catalyst used in the present invention, a) a metallocene compound is represented by the following general formula (1)

[0011]

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(Wherein Cp ¹ and Cp ² are each independently a substituted or unsubstituted cyclopentadienyl group, an indenyl group or a fluorenyl group, R ¹ is a hydrogen atom, a substituted or unsubstituted alkylene group, A dialkylsilanediyl group, a dialkylgermandiyl group, an alkylphosphinediyl group or an alkylimino group, wherein R ² and R ³ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group or Is an aryloxy group, and M ¹ is titanium, zirconium or hafnium), and is preferably a compound represented by the general formula (2), (3) or (4)

[0013]

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[0014]

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[0015]

[Chemical 4]

(In the formulas (2) and (3), Cp ³ and Cp ⁴ are each independently a substituted or unsubstituted cyclopentadienyl group, and R ⁴ is a substituted or unsubstituted alkylene group, dialkyl A silanediyl group, a dialkylgermandiyl group, an alkylphosphinediyl group or an alkylimino group, R ⁴ acts so as to bridge Cp ³ and Cp ⁴ , and R ² and R ³ are each independently a hydrogen atom. , A halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group or an aryloxy group, and in the formula (4), Cp ⁵ , Cp ⁶
Are each independently a substituted or unsubstituted cyclopentadienyl group, an indenyl group or a fluorenyl group,
R ² and R ³ are each independently a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group or an aryloxy group, and R ⁵ and R ⁶ are each independently a hydrogen atom, a substituted or unsubstituted atom. A substituted alkyl group, an alkoxy group or an aryl group, and M ² is titanium or zirconium)
Is a compound represented by.

As the hafnium compound of the formula (2) or (3), for example, bis (cyclopentadienyl) hafnium dichloride, bis (methylcyclopentadienyl) hafnium dichloride, bis (butylcyclopentadienyl) hafnium dichloride, Ethylenebis (indenyl) hafnium dichloride, dimethylsilylbis (2,4,5-trimethylcyclopentadienyl) hafnium dichloride, dimethylsilylbis (3
-Methylcyclopentadienyl) hafnium dichloride, dimethylsilylbis (4-t-butyl-2-methylcyclopentadienyl) hafnium dichloride, diethylsilylbis (2,4,5-trimethylcyclopentadienyl) hafnium dichloride, Diethylsilylbis (2,4-dimethylcyclopentadienyl) hafnium dichloride, diethylsilylbis (3-methylcyclopentadienyl) hafnium dichloride, diethylsilylbis (4-t-butyl-2-methylcyclopentadienyl) Hafnium dichloride, isopropyl (cyclopentadienyl) (fluorenyl) hafnium dichloride, diphenylmethylene (cyclopentadienyl) (fluorenyl) hafnium dichloride, methylphenylmethylene ( Clopentadienyl) (fluorenyl) hafnium dichloride, isopropyl (cyclopentadienyl) (2,7-di-t-butylfluorenyl) hafnium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-di- t-Butylfluorenyl) hafnium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) hafnium dichloride, isopropylidenebis (cyclopentadienyl) hafnium dichloride, diphenylmethylene Bis (cyclopentadienyl) hafnium dichloride, methylphenylmethylene bis (cyclopentadienyl) hafnium dichloride, isopropylidene (cyclopentadienyl) (tetramethylcyclopentadienyl) hafni Mujikuroraido, diphenylmethylene (cyclopentadienyl) (tetramethylcyclopentadienyl) hafnium dichloride, isopropylidene-bis (indenyl) hafnium dichloride, diphenylmethylene (indenyl)
Examples thereof include hafnium dichloride and methylphenylmethylene bis (indenyl) hafnium dichloride, but are not limited thereto.

Examples of the compound of the formula (4) include isopropylidene (cyclopentadienyl) (fluorenyl).
Titanium dichloride, isopropylidene (cyclopentadienyl) (fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl)
(Fluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (fluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, Isopropylidene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) titanium dichloride,
Isopropylidene (2,7-di-t-butylfluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) titanium dichloride, diphenylmethylene (cyclopentadiene) Enyl) (2,7-di-t-butylfluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7-di-t-butylfluorenyl) titanium dichloride,
Methylphenylmethylene (cyclopentadienyl)
(2,7-Di-t-butylfluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (2,7-dimethylfluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl)
(2,7-Dimethylfluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl)
(2,7-Dimethylfluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl)
(2,7-Dimethylfluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7-dimethylfluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7-dimethyl Fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (2,7-diphenylfluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl) (2,7-diphenylfluorenyl) zirconium dichloride, diphenyl Methylene (cyclopentadienyl) (2,7-diphenylfluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (2,7-diphenylfluorenyl) zirconium dichloride, Le phenylmethylene (cyclopentadienyl) (2,7-diphenyl fluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) (2,7-diphenyl fluorenyl)
Zirconium dichloride, isopropylidene (cyclopentadienyl) (a, i-dibenzofluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl) (a, i-dibenzofluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadiene) Dienyl) (a, i-dibenzofluorenyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (a, i-dibenzofluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (a, i -Dibenzofluorenyl) titanium dichloride, methylphenylmethylene (cyclopentadienyl) (a, i-dibenzofluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl) ( , H-Dibenzofluorenyl) titanium dichloride, isopropylidene (cyclopentadienyl) (b, h-dibenzofluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadienyl) (b, h-dibenzofluorenyl) Titanium dichloride, diphenylmethylene (cyclopentadienyl) (b, h-dibenzofluorenyl) zirconium dichloride, methylphenylmethylene (cyclopentadienyl) (b, h-dibenzofluorenyl) titanium dichloride, methylphenylmethylene ( Cyclopentadienyl) (b, h-dibenzofluorenyl) zirconium dichloride, bis (4-methylphenyl) methylene (cyclopentadienyl) (fluorenyl) titanium dichloride, bis (4-me) Ruphenyl) methylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, bis (4-phenylphenyl) methylene (cyclopentadienyl) (fluorenyl) titanium dichloride, bis (4-phenylphenyl) methylene (cyclopentadienyl) ( Fluorenyl) zirconium dichloride, isopropylidenebis (cyclopentadienyl) titanium dichloride, isopropylidenebis (cyclopentadienyl) zirconium dichloride, diphenylmethylenebis (cyclopentadienyl) titanium dichloride, diphenylmethylenebis (cyclopentadienyl) Zirconium dichloride, methylphenylmethylenebis (cyclopentadienyl) titanium dichloride, methylphenylmethylenebi Sus (cyclopentadienyl) zirconium dichloride, isopropylidene (cyclopentadienyl) (tetramethylcyclopentadienyl) titanium dichloride, isopropylidene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride, diphenylmethylene (Cyclopentadienyl)
(Tetramethylcyclopentadienyl) titanium dichloride, diphenylmethylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride, isopropylidene bis (indenyl)
Titanium dichloride, isopropylidenebis (indenyl) zirconium dichloride, diphenylmethylenebis (indenyl) titanium dichloride, diphenylmethylenebis (indenyl) zirconium dichloride, methylphenylmethylenebis (indenyl) titanium dichloride, methylphenylmethylenebis (indenyl) zirconium dichloride, etc. Is mentioned.

Of these, the substituent Cp ⁶ in the general formula (4) is a substituted or unsubstituted fluorenyl group and / or
Alternatively, a metallocene compound in which at least one of the substituents R ⁵ and R ⁶ is a substituted or unsubstituted aryl group is preferable because efficient copolymerization can be performed.

The b) ionized ionic compound used in the present invention is a compound capable of converting the a) metallocene compound into a cationic metallocene compound and is a compound which does not react with the produced cationic metallocene compound. , Specifically, tri-n-butylammonium tetrakis (p-tolyl) borate, tri-n-butylammonium tetrakis (m-tolyl) borate, tri-
n-butylammonium tetrakis (2,4-dimethylphenyl) borate, tri-n-butylammonium tetrakis (3,5-dimethylphenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, N, N- Dimethylanilinium tetrakis (p-tolyl) borate, N, N-Dimethylanilinium tetrakis (m-tolyl) borate, N, N
-Dimethylanilinium tetrakis (2,4-dimethylphenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, triphenylcarbenium tetrakis (p-tolyl) borate, triphenylcarbenium tetrakis (m-) Tolyl) borate, triphenylcarbenium tetrakis (2,4-dimethylphenyl) borate, triphenylcarbenium tetrakis (3,5-dimethylphenyl)
Borate, triphenylcarbenium tetrakis (pentafluorophenyl) borate, tropylium tetrakis (p-tolyl) borate, tropylium tetrakis (m-tolyl) borate, tropylium tetrakis (2,4-dimethylphenyl) borate, tropylium tetrakis (3,5-dimethylphenyl) borate, tropylium tetrakis (pentafluorophenyl) borate, lithium tetrakis (pentafluorophenyl)
Borate, lithium tetrakis (phenyl) borate,
Lithium tetrakis (p-tolyl) borate, lithium tetrakis (m-tolyl) borate, lithium tetrakis (2,4-dimethylphenyl) borate, lithium tetrakis (3,5-dimethylphenyl) borate, lithium tetrafluoroborate, sodium tetrakis ( Pentafluorophenyl) borate, sodium tetrakis (phenyl) borate, sodium tetrakis (p-tolyl) borate, sodium tetrakis (m-)
Tolyl) borate, sodium tetrakis (2,4-dimethylphenyl) borate, sodium tetrakis (3,5-dimethylphenyl) borate, sodium tetrafluoroborate, potassium tetrakis (pentafluorophenyl) borate, potassium tetrakis (phenyl) borate, potassium Tetrakis (p-tolyl) borate, potassium tetrakis (m-tolyl) borate,
Boron compounds such as potassium tetrakis (2,4-dimethylphenyl) borate, potassium tetrakis (3,5-dimethylphenyl) borate, potassium tetrafluoroborate, tri-n-butylammonium tetrakis (p-tolyl) aluminate, tri- n-butylammonium tetrakis (m-tolyl) aluminate, tri-n-butylammonium tetrakis (2,4-dimethylphenyl) aluminate, tri-n-butylammonium tetrakis (3,5-dimethylphenyl) aluminate, tri -N-butylammonium tetrakis (pentafluorophenyl) aluminate, N, N-dimethylanilinium tetrakis (p-tolyl) aluminate,
N, N-dimethylanilinium tetrakis (m-tolyl) aluminate, N, N-dimethylanilinium tetrakis (2,4-dimethylphenyl) aluminate,
N, N-dimethylanilinium tetrakis (pentafluorophenyl) aluminate, triphenylcarbenium tetrakis (p-tolyl) aluminate, triphenylcarbenium tetrakis (m-tolyl) aluminate, triphenylcarbenium tetrakis (2,2) 4-dimethylphenyl) aluminate, triphenylcarbenium tetrakis (3,5-dimethylphenyl) aluminate, triphenylcarbenium tetrakis (pentafluorophenyl) aluminate, tropylium tetrakis (p-tolyl) aluminate, tropylium Tetrakis (m-tolyl) aluminate, Tropylium tetrakis (2,4-dimethylphenyl) aluminate, Tropylium tetrakis (3,5-dimethylphenyl) aluminate, Tropiliu Tetrakis (pentafluorophenyl) aluminate, lithium tetrakis (pentafluorophenyl) aluminate, lithium tetrakis (phenyl) aluminate, lithium tetrakis (p- tolyl) aluminate, lithium tetrakis (m-tolyl)
Aluminate, lithium tetrakis (2,4-dimethylphenyl) aluminate, lithium tetrakis (3,5
-Dimethylphenyl) aluminate, lithium tetrafluoroaluminate, sodium tetrakis (pentafluorophenyl) aluminate, sodium tetrakis (phenyl) aluminate, sodium tetrakis (p)
-Tolyl) aluminate, sodium tetrakis (m-
Trily) aluminate, sodium tetrakis (2,4
-Dimethylphenyl) aluminate, sodium tetrakis (3,5-dimethylphenyl) aluminate, sodium tetrafluoroaluminate, potassium tetrakis (pentafluorophenyl) aluminate, potassium tetrakis (phenyl) aluminate, potassium tetrakis (p-tolyl) ) Aluminum compounds such as aluminate, potassium tetrakis (m-tolyl) aluminate, potassium tetrakis (2,4-dimethylphenyl) aluminate, potassium tetrakis (3,5-dimethylphenyl) aluminate, potassium tetrafluoroaluminate, etc. However, the present invention is not limited to these.

Further, the c) organoaluminum compound used in the present invention is represented by the following general formula (5):

[0022]

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(In the formula, R ⁶ , R ^{6 ′} and R ^{6 ″} are each independently a hydrogen atom, a halogen atom, an amido group, an alkyl group, an alkoxy group or an aryl group, and at least one is an alkyl group. A), specifically, trimethyl aluminum, trimethyl aluminum, triisopropyl aluminum, diisopropyl aluminum chloride, isopropyl aluminum dichloride, tributyl aluminum, triisobutyl aluminum, diisobutyl aluminum chloride, isobutyl aluminum dichloride, tri-t- Butyl aluminum, di-t-butyl aluminum chloride, t-butyl aluminum dichloride, triamyl aluminum, diamyl aluminum chloride, amyl aluminum dichloride Ride and the like are mentioned, but the present invention is not limited to these.

In the present invention, a method for preparing a catalyst from the above a) metallocene compound, b) ionized ionic compound and c) organoaluminum compound is, for example, a method of mixing these compounds in an inert solvent. However, the present invention is not limited to these.

The amount of the b) ionized ionic compound used in the present invention is 0.1 with respect to the a) metallocene compound.
˜100 times mol, particularly preferably 0.5 to 30 times mol.

Further, the amount of c) the organoaluminum compound is not particularly limited, but it is preferably 1 to 10000 mol per mol of the a) metallocene compound.

The adsorbent used in the present invention includes at least one of zeolite, activated alumina and activated carbon.

Further, as the α-olefin having 3 or more carbon atoms, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, styrene and the like can be mentioned, and one of them can be mentioned. You may use, or may mix and use 2 or more types. The α-olefin is not limited to the above.

[0029]

EXAMPLES The present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Table 1 shows the main conditions and the results of catalytic activity of each example and comparative example.

Example 1 In a process for producing an ethylene / α-olefin copolymer by a high temperature and high pressure method, a fixed bed adsorption tower (adsorbent: activated alumina) was installed between a separator and a compressor in a recycling process. , Reaction pressure 900 kg / cm ² , reaction temperature 153 ° C.,
Continuous operation was carried out for 60 hours while stirring at 1500 rpm.

As the metallocene catalyst, diphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate and triisobutylaluminum are boron / zirconium = 1/1, aluminum / A toluene solution having a zirconium concentration of 650 μmol / l was used at a molar ratio of zirconium = 250/1.

Example 2 The procedure of Example 1 was repeated, except that zeolite was used instead of activated alumina as the adsorbent for the fixed bed adsorption tower.

Example 3 Example 3 was repeated except that activated carbon was used instead of activated alumina as the adsorbent for the fixed bed adsorption tower.

Comparative Example 1 The procedure of Example 1 was repeated except that the fixed bed adsorption tower was not installed.

Example 4 Example 1 except that the reaction pressure was 1500 kg / cm ^2.
I went the same way.

Comparative Example 2 The procedure of Example 1 was repeated except that the reaction pressure was 1500 kg / cm ² and no fixed bed adsorption tower was installed.

Example 5 A metallocene-catalyzed diphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride was replaced by ethylenebis (indenyl) hafnium dichloride at a boron / hafnium molar ratio of 2 and a hafnium concentration of 650 μmol / l. The same procedure as in Example 1 was carried out except that the above adjustment was made.

Comparative Example 3 The procedure of Example 5 was repeated except that the fixed bed adsorption tower was not installed.

EXAMPLE 6 Instead of metallocene-catalyzed diphenylmethylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, diphenylmethylene (cyclopentadiene).
The zirconium concentration was adjusted to 300 μmol / l using (2,7-dimethylfluorenyl) zirconium dichloride, the reaction pressure was 500 kg / cm ² , and the reaction temperature was 1.
The same procedure as in Example 1 was performed except that the temperature was set to 80 ° C.

Comparative Example 4 The procedure of Example 6 was repeated except that the fixed bed adsorption tower was installed in front of the separator in the recycling process.

[0041]

[Table 1]

[0042]

As described above, according to the method for removing impurities of the present invention, the ethylene / α-olefin copolymer can be produced without lowering the activity of the metallocene catalyst.

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process by a high temperature and high pressure method.

FIG. 2 is a view showing a fixed bed adsorption tower (impurity removing device).

Claims (4)

[Claims] 1. In a method for producing an ethylene / α-olefin copolymer in which ethylene and an α-olefin having 3 or more carbon atoms are copolymerized with a metallocene catalyst under conditions of high temperature and high pressure, unreacted gas after the polymerization reaction is A production method comprising passing through a fixed bed adsorption tower. 2. A method for producing an ethylene / α-olefin copolymer, wherein the fixed bed adsorption tower according to claim 1 is provided between a separator and a compressor in a recycling process. 3. Zeolite, activated alumina, as an adsorbent,
At least 1 sort (s) of activated carbon is used, The manufacturing method of the ethylene / (alpha)-olefin copolymer of Claim 1 or 2 characterized by the above-mentioned. 4. A reaction pressure of 400 kg / cm ² or more 400
0 kg / cm ² or less, the reaction temperature is 120 ° C. or more and 300
The method for producing an ethylene / α-olefin copolymer according to claim 1, 2 or 3, wherein the reaction is performed at a temperature of not higher than ° C.