JPH11228622A - Production of ethylene-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for efficiently producing an ethylene-based polymer suitable for blow-molded products (esp. large-sized ones) with excellent balance between rigidity and creep resistance. SOLUTION: This method for producing an ethylene-based polymer comprises using (1) a catalyst with a carrier bearing an organic group-bearing chromium compound selected from chromium carboxylates, chromium-1,3-diketo compounds, chromic esters and chromic acid amides, an alumoxane, organometal alkoxide and/or organometal siloxide and (2) an activator selected from organolithium compounds, organomagnesium compounds, organoaluminum compounds and organoboron compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an ethylene polymer. More specifically, a chromium compound, alumoxane, an organometallic alkoxide and / or an organometallic siloxide supported on a carrier and a catalyst and an activator are used, and are particularly suitable for a large-sized blow such as a blow having an excellent balance between rigidity and creep resistance. And a method for producing an ethylene polymer.

[0002]

2. Description of the Related Art Ethylene polymers are generally and widely used as resin materials for various molded articles, and required characteristics differ depending on the molding method and application. For example, polymers having a relatively low molecular weight and a narrow molecular weight distribution are suitable for products molded by injection molding. On the other hand, a polymer having a relatively high molecular weight and a wide molecular weight distribution is suitable for a product molded by inflation molding or blow molding. It has been known that an ethylene polymer having a wide molecular weight distribution suitable for blow molding or the like can be obtained by using a so-called Phillips catalyst in which chromium trioxide is supported on an inorganic oxide such as silica. Also, ethylene-based polymers having a wide molecular weight distribution suitable for blow molding and the like can be obtained by single-stage or multi-stage polymerization using a Ziegler catalyst disclosed in JP-A-2-123108, JP-A-4-18407, JP-A-5-230136 and the like. Coalescence is obtained.

However, in recent years, there has been a demand for higher quality ethylene polymers suitable for large blow molding such as gasoline tanks and large drums. When a blow molded article is produced using an ethylene polymer having a wide molecular weight distribution obtained by the above catalyst, the molded article has a poor balance between rigidity and creep resistance. That is, (1) When the rigidity is increased, the creep resistance is deteriorated. (2) When the creep resistance is increased, the rigidity is inferior. It is not always satisfactory in any of these points. Recently, Japanese Patent Publication No. 7-503739 discloses a method for obtaining an ethylene polymer having a wide molecular weight distribution by using a catalyst comprising one kind of chromium compound and alumoxane. However, it is difficult to say that the balance between rigidity and creep resistance of the ethylene-based polymer obtained by this method is at a sufficient level.

JP-A-2-105806, JP-A-2-2-1
No. 85506 discloses a solid catalyst component in which chromium trioxide or a chromium compound which forms at least partially chromium oxide upon firing is supported on an inorganic oxide carrier, and a catalyst comprising an alumoxane, an organic aluminum alkoxide or an organic aluminum siloxide. A method for obtaining an ethylene-based polymer having a wide distribution is disclosed. However, the ethylene polymer obtained by this method also has
The balance between rigidity and creep resistance is not at a sufficient level. JP-B-44-2996, JP-B-44-3827
JP-B-47-1766 discloses a method for obtaining an ethylene polymer having a wide molecular weight distribution by using a catalyst in which a chromate ester is supported on an inorganic oxide carrier such as silica. However, the balance between rigidity and creep resistance of the ethylene-based polymer obtained by this method is not at a sufficient level. JP-A-54-120290 describes that
There is disclosed a method for obtaining an ethylene polymer having a wide molecular weight distribution by a catalyst comprising a solid component in which a chromate ester is supported on silica and then treated with an organoaluminum alkoxide and alumoxane. However, the balance between rigidity and creep resistance of the ethylene-based polymer obtained by this method is not at a sufficient level.

US Pat. No. 5,104,841 and US Pat. No. 5,137,997 disclose a method for obtaining an ethylene polymer having a wide molecular weight distribution by using a catalyst in which a chromamide compound is supported on an inorganic oxide carrier such as silica. Have been. However, the balance between rigidity and creep resistance of the ethylene-based polymer obtained by this method is not at a sufficient level. U.S. Pat. No. 5,137,994 discloses that ethylene (bis (triphenylsilyl) chromate), a kind of chromate, is supported on silica, and then a catalyst supporting triisobutylaluminum is used to form an ethylene-based polymer having a wide molecular weight distribution by a gas phase polymerization method. A method for obtaining a polymer is disclosed. According to this method, a part of ethylene is trimerized to 1-hexene, and ethylene and this by-produced 1-hexene are copolymerized to obtain an ethylene polymer. The obtained ethylene-based polymer has a melt flow rate (HLMFR shown by the measuring method used in the following Examples and Comparative Examples) suitable for large-size blow applications, but the rigidity and creep resistance balance at a sufficient level. Absent. Also, the ratio of triisobutylaluminum and bis (triphenylsilyl) chromate to be supported determines the amount of 1-hexene produced as a by-product, and the density of the obtained ethylene-based polymer is determined. And the entire manufacturing process becomes complicated and economically disadvantageous.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the above problems and efficiently produce an ethylene polymer particularly suitable for large-size blows, such as blows having a good balance between rigidity and creep resistance. The purpose is to provide a way to:

[0007]

Means for Solving the Problems The inventors of the present invention have made intensive studies in view of the above problems, and have found that a catalyst and an activator having a chromium compound, an alumoxane, an organometallic alkoxide and / or an organometallic siloxide supported on a carrier. The object has been solved by a method for producing an ethylene-based polymer, which is characterized in that it is used. That is, the present invention relates to [1] (1) a chromium compound having an organic group selected from chromium carboxylate, chromium-1,3-diketo compound, chromate ester and chromamide compound, alumoxane, organometallic alkoxide and / or A method for producing an ethylene-based polymer, comprising using a catalyst in which an organometallic siloxide is supported on a carrier, and (2) an activator.

[2] (1) A chromium compound having an organic group selected from a chromium carboxylate, a chromium-1,3-diketo compound, a chromate ester and a chromamide compound is supported on a carrier, and then alumoxane, an organic metal alkoxide And / or a catalyst supporting organometallic siloxide,
And (2) a method for producing an ethylene-based polymer according to the above [1], characterized by using an activator; [3] polymerization after contacting the activator with a catalyst in the presence or absence of ethylene. The method for producing an ethylene-based polymer according to the above [1] or [2], wherein

[4] As a component supported on a carrier,
A ratio of (aluminum atom in alumoxane) / (chromium atom in chromium compound) is 0.5 to 100;
(Metal atom in organometallic alkoxide and / or organometallic siloxide) / (chromium atom in chromium compound)
Is from 0.5 to 100, and (aluminum atom in alumoxane) / (organometallic alkoxide and / or
Or the metal atom in the organometallic siloxide) is 0.0
The method for producing an ethylene-based polymer according to any one of the above [1] to [3], wherein the carrier is an inorganic metal oxide (solid acid or Lewis acid) and / or
Or the above-mentioned [1] to [4] which are inorganic halides
The method for producing an ethylene-based polymer according to any one of the above,
[6] The carrier has a specific surface area of 50 to 1000 m ² / g, a pore volume of 0.5 to 3.0 cm ³ / g, and an average particle size of 10 to 10.
The chromium compound having an organic group is used as a chromium atom in an amount of 0.05 to 5.0 w
The method for producing an ethylene-based polymer according to the above [5], which is a catalyst loaded with t%,

[7] The process for producing an ethylene polymer according to any one of the above [1] to [6], wherein the alumoxane is an alkylalumoxane, [8] the organometallic alkoxide and / or the organometallic siloxide is cyclically regulated. The method for producing an ethylene-based polymer according to any one of the above [1] to [6], which is an organometallic alkoxide and / or an organometallic siloxide of Table 2 or 13; [9]
[10] The method for producing an ethylene-based polymer according to [8], wherein the organometallic alkoxide and / or the organometallic siloxide is selected from organoaluminum alkoxides, organoaluminum siloxides, organomagnesium alkoxides, and organoboron alkoxides; Is selected from organic lithium compounds, organic magnesium compounds, organic aluminum compounds, and organic boron compounds [1].
[10] The method according to any one of [1] to [3], wherein the activator is selected from an alkyllithium compound, a dialkylmagnesium compound, a trialkylaluminum compound, and a trialkylboron compound. The above object has been achieved by developing a method for producing an ethylene polymer described in (1).

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below. Examples of the chromium compound having an organic group used in the present invention include a chromium carboxylate, a chromium-1,3-diketo compound, a chromate ester, and a chromamide compound. Examples of the chromium carboxylate include compounds of chromium (II) or chromium (III) represented by the general formula (1) or (2).

Embedded image

Embedded image (R ¹ , R ² , R ³ , R ⁴ , and R ⁵ are each hydrogen or a hydrocarbon group having 1 to 18 carbon atoms, and may be the same or different.)

Specific examples include chromium (II) formate, chromium (II) acetate, chromium (II) propionate, chromium (II) butyrate, chromium (II) pentanoate, chromium (II) hexanoate, and 2-ethyl Chromium (II) hexanoate, chromium (II) benzoate, chromium (II) naphthenate, chromium (II) oleate, chromium oxalate (II), chromium formate (II)
Chromium (III) acetate, chromium (III) propionate, chromium (III) butyrate, chromium (III) pentanoate, chromium (III) hexanoate, chromium (III) 2-ethylhexanoate, chromium benzoate ( III), chromium (III) naphthenate, chromium (III) oleate, chromium oxalate (III), and the like, chromium acetate (II), chromium (II) 2-ethylhexanoate, chromium (III) acetate, Chromium (III) 2-ethylhexanoate is preferred.

The chromium-1,3-diketo compound includes
A chromium (III) complex represented by the general formula (3) and having one to three 1,3-diketo compounds. _{CrX k Y m Z n (3} ) (X is a 1,3-diketo type chelate ligand, Y and Z is halogen, alkoxy, aryloxy, alkyl, aryl, selected from amides, be the same K + m + n = 3, 1 ≦ k ≦ 3, 0 ≦ m
≦ 2, 0 ≦ n ≦ 2. ) Specific examples include chromium-1,3-butanedionate,
Chromium acetylacetonate, chromium-2,4-hexanedionate, chromium-2,4-heptanedionate,
Chromium-2,4-octandionate, chromium-3,5
Octandionate, chromium benzoylacetonate, chromium-1,3-diphenyl-1,3-propanedionate, chromium-2-methyl-1,3-butanedionate, chromium-2-ethyl-1,3- Butanedionate, chromium-2-phenyl-1,3-butanedionate, chromium-1,2,3-triphenyl-1,3-propanedionate and the like are mentioned, and chromium acetylacetonate is preferred.

The chromic ester is represented by the general formula (4)
Is a compound of chromium (VI) represented by

Embedded image (R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , and R ¹¹ each have 1 carbon atom.
To 18 hydrocarbon groups, which may be the same or different. M ¹ and M ² each represent a carbon atom or a silicon atom. As specific examples, when M ¹ and M ² are carbon, bis (tert-butyl) chromate, bis (1,1-dimethylpropyl) chromate, bis (1-methyl-1-phenylethyl) chromate, bis ( 1,1-diphenylethyl) chromate, bis (triphenylmethyl) chromate, bis (1,1,2,2-tetramethylpropyl) chromate, bis (1,1,2-trimethylpropyl) chromate and the like, Bis (tert-butyl) chromate is preferred.

When M ¹ and M ² are silicon, bis (trimethylsilyl) chromate, bis (triethylsilyl) chromate, bis (tributylsilyl) chromate, bis (triisopentylsilyl) chromate, bis (tri-2-yl) chromate Ethylhexylsilyl) chromate, bis (tridecylsilyl) chromate, bis (tri (tetradecyl) silyl) chromate, bis (tribenzylsilyl) chromate, bis (triphenethylsilyl) chromate, bis (triphenylsilyl) chromate, bis (tri Tolylsilyl) chromate, bis (trixylylsilyl) chromate, bis (trinaphthylsilyl) chromate, bis (dimethylphenylsilyl) chromate,
Bis (diphenylmethylsilyl) chromate, bis (dimethyltexylsilyl) chromate, bis (dimethylisopropylsilyl) chromate, bis (tert-butyldimethylsilyl) chromate, bis (tri-tert)
-Butylsilyl) chromate, bis (triethylphenylsilyl) chromate, bis (trimethylnaphthylsilyl) chromate, polydiphenylsilylchromate, polydiethylsilylchromate and the like, with bis (triphenylsilyl) chromate being preferred.

Examples of the chromamide compound include compounds of chromium (II) or chromium (III) represented by the general formula (5) or (6).

Embedded image (R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ , R ¹⁸ , R ¹⁹ ,
R ²⁰ , R ²¹ , R ²² , and R ²³ each represent hydrogen or a group having 1 to 1 carbon atoms.
8 hydrocarbon groups, which may be the same or different. M ³ , M ⁴ , M ⁵ and M ^{6 each} represent a carbon and / or silicon atom, L represents a ligand such as ether or nitrile, and 0 ≦ p ≦ 2. )

Embedded image (R ²⁴ , R ²⁵ , R ²⁶ , R ²⁷ , R ²⁸ , R ²⁹ , R ³⁰ , R ³¹ ,
^R32 , ^R33 , ^R34 , ^R35 , ^R36 , ^R37 , ^R38 , ^R39 , R
⁴⁰ and R ⁴¹ are each hydrogen or a hydrocarbon group having 1 to 18 carbon atoms, which may be the same or different. M ^7, M
⁸ , M ⁹ , M ¹⁰ , M ¹¹ and M ¹² are carbon and / or silicon atoms. )

As specific examples, bis (bistrimethylsilylamide) chromium (II) -THF complex, bis (bistrimethylsilylamide) chromium (II) -diethyl ether complex, bis (methyltrimethylsilylamide) chromium (II) -THF complex , Bis (methyltrimethylsilylamide) chromium (II) -diethyl ether complex, bis (t
tert-butyltrimethylsilylamide) chromium (II)
-THF complex, bis (tert-butyltrimethylsilylamide) chromium (II) -diethyl ether complex, bis (phenyltrimethylsilylamide) chromium (II) -T
HF complex, bis (phenyltrimethylsilylamide) chromium (II) -diethyl ether complex, tris (dimethylamido) chromium (III), tris (diethylamido) chromium (III), tris (diisopropylamido) chromium (I)
II), tris (methylphenylamide) chromium (III),
Tris (diphenylamide) chromium (III), tris (bistrimethylsilylamide) chromium (III), tris (bistriethylsilylamide) chromium (III), tris (bistriphenylsilylamide) chromium (III) and the like.

Alumoxane is a compound well known in the art, but its preparation and structure are Polyhed.
ron, 9, 429-453 (1990), Ziegl
erCatalysts, G. et al. Fink et al.
(Eds.) 57-82, Springer-Verl.
ag (1995). The alumoxane used in the present invention is represented by the following general formula (7)
Or the compound represented by (8) is mentioned.

Embedded image

Embedded image (R ⁴² is a methyl group, an ethyl group, a propyl group, n- butyl group, a hydrocarbon group such as an isobutyl group, preferably, 100 to .q 1 is a methyl group, an isobutyl group
And is preferably 4 or more, particularly preferably 8 or more. )

The preparation of this type of compound is known, and examples thereof include salts having water of crystallization (such as copper sulfate hydrate and aluminum sulfate hydrate) such as pentane, hexane, heptane, cyclohexane, decane, benzene, and toluene. Examples of the method include a method of producing a suspension of an inert hydrocarbon solvent by adding a trialkylaluminum, and a method of allowing solid, liquid or gaseous water to act on a trialkylaluminum in a hydrocarbon solvent. it can.

Further, an alumoxane represented by the general formula (9) or (10) may be used.

Embedded image

Embedded image (R ⁴³ is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group, an n-butyl group, an isobutyl group, and is preferably a methyl group or an isobutyl group. Further, R44 is a methyl group, an ethyl group, propyl group, n- butyl group, a hydrocarbon group such as an isobutyl group or a chlorine, a halogen or hydrogen, such as bromine, is selected from hydroxyl, exhibit different radicals from R ^43. Further, R ⁴⁴ is either the same or different You may.
r is usually an integer of 1 to 100, preferably 3 or more, and r + s is 2 to 101, preferably 6 or more. )

In the compound of the general formula (9) or (10), the (O-Al (R ⁴³ )) unit and the (O-Al
(R ⁴⁴ )) The units may be connected in blocks or may be connected regularly or irregularly at random. The method for producing such an alumoxane is the same as that for the above-described alumoxane of the general formula. Instead of one kind of trialkylaluminum, two or more kinds of trialkylaluminum are used, or one or more kinds of dialkylaluminum monohalide or dialkylaluminum are used. Aluminum monohydride or the like may be used.

Examples of the organometallic alkoxide and / or organometallic siloxide used in the present invention include a group of organometallic alkoxides and / or organometallic siloxides of Group 2 or 13 of the periodic table. , (12), (13) or (14). R ⁴⁵ _t Al (OR ₄₆ ) _3-t (11) (R ⁴⁵ and R ⁴⁶ are hydrocarbon groups having 1 to 18 carbon atoms, and may be the same or different. t is 1 or 2.) R ⁴⁷ R ⁴⁸ R ⁴⁹ Si—O—AlR ⁵⁰ R ⁵¹ (12) (R ⁴⁷ , R ⁴⁸ , R ⁴⁹ , R ⁵⁰ , and R ⁵¹ are carbon atoms. 1 to 18 hydrocarbon groups, which may be the same or different.) R ⁵² Mg (OR ⁵³ ) (13) (R ⁵² and R ^{53 each} have 1 to 18 carbon atoms.) R ⁵⁴ _u B (OR ⁵⁵ ) ₃ -u (14) (R ⁵⁴ and R ^{55 each} have 1 to 1 carbon atoms) 18 hydrocarbon groups, which may be the same or different, and u is 1 or 2.)

The above general formula (11): R ⁴⁵ _t Al (OR ⁴⁶ ) _{3 -t} (11) (R ⁴⁵ and R ⁴⁶ are hydrocarbon groups having 1 to 18 carbon atoms and are the same. And t is 1 or 2. Specific examples of the organoaluminum alkoxide represented by the formula: dimethylaluminum methoxide, dimethylaluminum ethoxide, dimethylaluminum isopropoxide, dimethylaluminum n-butoxide,
Dimethylaluminum isobutoxide, diethylaluminum ethoxide, diethylaluminum isopropoxide, diethylaluminum n-butoxide, diethylaluminum isobutoxide, diisobutylaluminum ethoxide, diisobutylaluminum isopropoxide, diisobutylaluminum n-butoxide, diisobutylaluminum isobutoxide, diisobutylaluminum n-hexylaluminum ethoxide, di-n-hexylaluminum isopropoxide, di-n-hexylaluminum n-butoxide, din-hexylaluminum isobutoxide, methylaluminum dimethoxide, methylaluminum diethoxide, methylaluminum diisopropoxide , Methylaluminum di-n-butoxide, methylaluminum diisobut Oxide, ethylaluminum diethoxide, ethylaluminum diisopropoxide, ethylaluminum di-n-butoxide, ethylaluminum diisobutoxide, isobutylaluminum diethoxide, isobutylaluminum diisopropoxide, isobutylaluminum din-butoxide, isobutylaluminum Examples thereof include diisobutoxide, n-hexylaluminum diethoxide, n-hexylaluminum diisopropoxide, n-hexylaluminum din-butoxide, and n-hexylaluminum diisobutoxide.

Of these, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, dimethyl aluminum isopropoxide, dimethyl aluminum n-
Butoxide, dimethyl aluminum isobutoxide, diethyl aluminum ethoxide, diethyl aluminum isopropoxide, diethyl aluminum n-butoxide, diethyl aluminum isobutoxide, diisobutyl aluminum ethoxide, diisobutyl aluminum isopropoxide, diisobutyl aluminum n-butoxide, diisobutyl aluminum isobutoxide And monoalkoxides such as di-n-hexylaluminum ethoxide, di-n-hexylaluminum isopropoxide, di-n-hexylaluminum n-butoxide, and di-n-hexylaluminum isobutoxide. These compounds can be easily synthesized by a known method. For example, the general formula R ⁴⁵ ₃ methods by reaction with an alcohol represented by the trialkyl aluminum and the general formula R ⁴⁶ OH represented by Al or the formula trialkylaluminum general formula represented by R ⁴⁵ ₃ Al, Al (OR ⁴⁶ )
_Although there is a method obtained by an exchange reaction with an aluminum trialkoxide represented by ₃ , the former is preferred in the present invention.

The above general formula (12): R ⁴⁷ R ⁴⁸ R ⁴⁹ Si—O—AlR ⁵⁰ R ⁵¹ (12) (R ⁴⁷ , R ⁴⁸ , R ⁴⁹ , R ⁵⁰ and R ^{51 each} have 1 to carbon atoms. Specific examples of the organoaluminum siloxide represented by the formula: are trimethyldimethylsiloxyalane, trimethyldiethylsiloxyalane, trimethyldiisobutylsiloxyalane, and trimethyl. Di-n-hexylsiloxyalan, triethyldimethylsiloxyalan, triethyldiethylsiloxyalan, triethyldiisobutylsiloxyalan, triethyldi-n-hexylsiloxyalan, triphenyldimethylsiloxyalan, triphenyldiethylsiloxyalan, triphenyldiisobutylsiloxyalan, triphenyldin- F Xylsiloxyalan and the like. Among these, trimethyldimethylsiloxyalan, trimethyldiethylsiloxyalan, trimethyldiisobutylsiloxyalan, trimethyldi-n-hexylsiloxyalan, triethyldimethylsiloxyalan, triethyldiethylsiloxyalan,
Triethyldiisobutylsiloxyalane and triethyldi-n-hexylsiloxyalane are preferred.

The above-mentioned organoaluminum siloxides are: 1) Reaction of a silanol compound represented by the general formula R ⁴⁷ R ⁴⁸ R ⁴⁹ Si—OH with an organoaluminum compound represented by the general formula R ⁵⁰ R ⁵¹ RAl 2) a method known by the reaction of a cyclic siloxane with an organoaluminum compound represented by the general formula R ⁵⁰ R ⁵¹ RAl; 3) a reaction of a polysiloxane with an organoaluminum compound represented by the general formula R ⁵⁰ R ⁵¹ RAl Can be synthesized. 1) ~
In 3), R ^{47 to} R ⁵¹ are represented by the general formula R ⁴⁷ R ⁴⁸ R ⁴⁹ Si—
O-AlR the same as R ⁴⁷ to R ⁵¹ in ⁵⁰ R ^51, R
Are those in the general formula ^{R 47 R 48 R 49 Si-} O-AlR 50 R 51 equivalent to the R ⁴⁷ to R ^51, represents a group which is substituted in the reaction.

The general formula (13): R ⁵² Mg (OR ⁵³ ) (13) (R ⁵² and R ⁵³ are hydrocarbon groups having 1 to 18 carbon atoms, and Specific examples of the organomagnesium alkoxide represented by the formula: ethyl magnesium methoxide, ethyl magnesium ethoxide,
Ethyl magnesium isopropoxide, ethyl magnesium n-butoxide, ethyl magnesium isobutoxide, ethyl magnesium phenoxide, butyl magnesium methoxide, butyl magnesium ethoxide, butyl magnesium isopropoxide, butyl magnesium n-butoxide, butyl magnesium isobutoxide,
Examples thereof include butylmagnesium phenoxide, and preferred are ethylmagnesium ethoxide, ethylmagnesium isopropoxide, ethylmagnesium n-butoxide, and ethylmagnesium isobutoxide. These compounds can be easily synthesized by a known method. For example, there is a method obtained by reacting a dialkylmagnesium represented by the general formula R ⁵² ₂ Mg with an alcohol represented by the general formula R ⁵³ OH.

The above general formula (14): R ⁵⁴ _uB (OR ⁵⁵ ) ₃ -u (14) (R ⁵⁴ and R ⁵⁵ are hydrocarbon groups having 1 to 18 carbon atoms and are the same. And u is 1 or 2. Specific examples of the organoboron alkoxide represented by the formula: dimethylmethoxyborane, dimethylethoxyborane, dimethylpropoxyborane, dimethylbutoxyborane, diethylmethoxy Borane, diethyl ethoxy borane, diethyl propoxy borane, diethyl butoxy borane, methyl dimethoxy borane, methyl diethoxy borane, methyl dipropoxy borane, methyl dibutoxy borane, ethyl dimethoxy borane, ethyl diethoxy borane, ethyl dipropoxy borane, ethyl dibutoxy Borane, phenyldimethoxyborane, phenyldiethoxy Siborane, phenyl dipropoxy borane, phenyl dibutoxy borane, diphenyl methoxy borane, diphenyl ethoxy borane, diphenyl propoxy borane, diphenyl butoxy borane, and the like.

Of these, dimethyl methoxy borane, dimethyl ethoxy borane, dimethyl propoxy borane, dimethyl butoxy borane, diethyl methoxy borane, diethyl ethoxy borane, diethyl propoxy borane, and diethyl butoxy borane are preferred. These compounds can be easily synthesized by a known method. For example, a Grignard reagent represented by the general formula R ⁵⁴ MgX (X is a halogen) or an organolithium reagent represented by the general formula R ⁵⁴ Li, and a borate represented by the general formula B (OR ⁵⁵ ) ₃ And a method of obtaining the same by an exchange reaction. The organometallic alkoxides and organometallic siloxides represented by the general formulas (11), (12), (13), and (14) may be used alone or in combination of two or more.

The carrier used in the present invention is a particulate solid, and is preferably a solid even in a polymerization medium.
Porous is particularly preferred. Specifically, inorganic metal oxides,
Inorganic halides, inorganic hydroxides, inorganic carbonates, inorganic phosphates, inorganic compounds such as inorganic sulfates, polyethylene,
Copolymer of polypropylene, polystyrene, or olefins such as ethylene, propylene, and styrene with polar group-containing monomers such as acrylic acid, acrylic ester, methacrylic acid, methacrylic ester, vinyl ether, acrylonitrile, allyl alcohol, and vinyl acetate Is used. In particular, the catalyst of the present invention is preferably used by being supported on a carrier that is commonly used as a component of an ethylene polymerization catalyst, such as an inorganic oxide or an inorganic halide.

The inorganic metal oxide is an oxide of a metal belonging to Group 2, 4, 13, or 14 of the periodic table. Specifically, magnesia, titania, zirconia, alumina, thoria, aluminum phosphate, Examples include silica, silica-titania, silica-zirconia, silica-alumina, and mixtures thereof. Here, aluminum phosphate is formally a phosphate, but is treated as an inorganic metal oxide because of its properties as an oxide. These inorganic metal oxides, the surface area is 50~1000m ² / g, preferably 200~800m ² / g, pore volume 0.5
3.0cm ³ / g, preferably 1.0~2.5cm ³ /
g, average particle size is 10 to 200 μm, preferably 30 to 1 μm.
Those having a size of 50 μm are preferably used. As these inorganic metal oxides, those obtained by firing at a temperature of 100 to 900 ° C. for 10 minutes to 24 hours under a stream of dry nitrogen gas under a molecular sieve stream are preferably used. The calcination is preferably carried out in a solid fluid state with a sufficient amount of nitrogen gas. In addition, a known method of adding a titanate, a fluorine-containing salt, or the like and firing the mixture may be used in combination. The inorganic halide is a halide of a metal belonging to Group 2 or 13 of the periodic table, and examples thereof include magnesium chloride, magnesium bromide, magnesium iodide, calcium chloride, aluminum chloride, gallium chloride, and mixtures thereof.

As a method for obtaining a catalyst using the above-mentioned components, a chromium compound having an organic group, an alumoxane, an organometallic alkoxide and / or an organometallic siloxide, and a carrier are introduced in advance into a reactor for preparing a catalyst, and the catalyst is prepared. A method of forming is used. Of these, a method is preferred in which a chromium compound having an organic group is supported on a carrier, and then alumoxane and an organic metal alkoxide and / or an organic metal siloxide are supported. As a method for supporting alumoxane and an organometallic alkoxide and / or an organometallic siloxide, (A) a method for supporting an organometallic alkoxide and / or an organometallic siloxide after supporting alumoxane, (B) an organometallic alkoxide and / or an organic metal alkoxide A method of supporting alumoxane after supporting metal siloxide, (C) a method of supporting a mixture of alumoxane and organometallic alkoxide and / or organometallic siloxide,
Either method may be used, but the method (A) is more preferable.

The supporting reaction of each component is carried out by propane, butane, isobutane, pentane, isopentane, hexane,
It is preferably carried out in an inert hydrocarbon solvent such as heptane, cyclohexane, decane, benzene, toluene and xylene. An arbitrary amount of the solvent can be used per 1 g of the carrier. Further, after the supported reaction, the supported catalyst can be separated from the solvent by a method such as removing the solvent under vacuum or separating by filtration. The amount of the chromium compound having an organic group carried on the carrier is preferably such that the amount of chromium atoms carried on the carrier is 0.05 to 5.0 wt%, preferably 0.05 to 2.0 wt%, based on the carrier.

The amount of alumoxane to be supported is such that the alumoxane has an atomic ratio of aluminum atoms to chromium atoms of 0.5 to 0.5.
A quantity such as to be 100 is preferred. The amount of the supported organometallic alkoxide and / or organometallic siloxide is
The atomic ratio of metal atoms to chromium atoms in the organometallic alkoxide and / or organometallic siloxide is 0.5 to 100.
Is preferably such that The molar ratio of alumoxane to the organometallic alkoxide and / or organometallic siloxide is preferably such that the molar ratio is from 0.01 to 100. The supporting reaction temperature is from 0 ° C. to the boiling point of the solvent, and the supporting reaction time is from 5 minutes to 24.
Time is preferred.

In carrying out the method for producing an ethylene-based polymer of the present invention, the above-mentioned catalyst may be carried out by a liquid phase polymerization method such as slurry polymerization or solution polymerization or a gas phase polymerization method. Can be. The liquid phase polymerization method is usually carried out in a hydrocarbon solvent, and as the hydrocarbon solvent, propane, butane, isobutane, pentane, isopentane,
Inert hydrocarbons, such as hexane, cyclohexane, heptane, benzene, toluene, xylene, alone or in a mixture are used. In the gas phase polymerization method, in the presence of an inert gas, a commonly known polymerization method such as a fluidized bed and a stirring bed can be employed, and a so-called condensing mode in which a medium for removing polymerization heat can coexist in some cases can be employed. . The polymerization temperature in liquid or gas phase polymerization is generally 0 to 3
00 ° C., and practically 20 to 200 ° C. In addition, hydrogen or the like can coexist in the polymerization reactor for controlling the molecular weight.

In the present invention, the polymerization is preferably carried out after contacting the activator with the catalyst in the presence or absence of ethylene. According to this polymerization method, a small amount of α-olefin such as 1-butene and 1-hexene is by-produced, and ethylene and this α-olefin by-produced are copolymerized. By this copolymerization,
The balance between rigidity and creep resistance can be improved,
The effects of the present invention can be achieved. Α- by-produced and copolymerized
Olefins are substantially 1-butene and 1-hexene, and the short-chain branches introduced into the ethylene-based polymer are ethyl branches and butyl branches.

As the activator used in the present invention, an organometallic compound, particularly an organometallic compound belonging to Group 1, 2, or 13 of the periodic table, specifically, an organolithium compound, an organomagnesium compound, or an organoaluminum Compounds and organic boron compounds are preferably used. Alkyl lithium is preferable as the organic lithium compound, and specific examples include methyllithium, ethyllithium, propyllithium, n-butyllithium, sec-butyllithium and t-butyllithium.
tert-butyllithium and the like, among which methyllithium and n-butyllithium are preferable. As the organomagnesium compound, a dialkylmagnesium compound is preferable, and specific examples include dimethylmagnesium, diethylmagnesium, dibutylmagnesium, dihexylmagnesium, methylethylmagnesium, methylbutylmagnesium, methylhexylmagnesium, butylethylmagnesium, ethylhexylmagnesium,
Butylhexylmagnesium and the like are mentioned, and among them, dibutylmagnesium and butylethylmagnesium are preferable. As the organoaluminum compound, a trialkylaluminum compound is preferable, and specific examples thereof include trimethylaluminum, triethylaluminum, and tri-n-
Propylaluminum, triisopropylaluminum, trin-butylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, tridodecylaluminum, etc., among which trimethylaluminum, triethylaluminum, triisobutylaluminum are particularly preferred. preferable. As the organic boron compound, a trialkyl boron compound is preferable, and specific examples include trimethyl borane, triethyl borane, tripropyl borane, tributyl borane, trihexyl borane, trioctyl borane, and the like. Among them, triethyl borane is particularly preferable.

As a method for contacting the catalyst with the activator, a) a method in which the catalyst and the activator are brought into contact in advance in the presence or absence of ethylene, and then introduced into a polymerization reactor to carry out polymerization; A method in which a catalyst and an activator are separately introduced into a polymerization reactor in the presence or absence of ethylene to perform polymerization. The amount of the activator to be brought into contact with the catalyst is such that the ratio of [metal atoms (lithium, magnesium, aluminum, boron) in the activator] / [chromium atoms carried] is 0.1 to 1000, preferably 0 to 1000. .2 to 50
The amount is preferably 0, more preferably 0.5 to 100. As this molar ratio is larger, the by-product amount of α-olefin increases, and the density of the obtained ethylene-based polymer decreases. That is, the density can be controlled by the molar ratio of metal atoms (lithium, magnesium, aluminum, boron) in the activator and chromium atoms in the catalyst, and there is no need to change the catalyst.

In the present invention, in order to obtain an ethylene polymer particularly suitable for large-size blow such as blow having an excellent balance between rigidity and creep resistance, a by-product α-olefin coexisting with ethylene in a polymerization reactor is required. Is the amount of 1.0 × 10 ⁻⁵ ≦ α-olefin concentration in liquid phase or gas phase (mol%) / ethylene concentration in liquid phase or gas phase (m
ol%) ≦ 1.0 × 10 ⁻² , more preferably 5.0 × 10 ⁻⁵ ≦ α-olefin concentration (mol%) in liquid phase or gas phase / ethylene concentration in liquid phase or gas phase ( m
ol%) ≦ 7.0 × 10 ⁻³ , particularly preferably 1.0 × 10 ⁻⁴ ≦ α-olefin concentration (mol%) in liquid phase or gas phase / ethylene concentration in liquid phase or gas phase ( m
ol%) ≦ 5.0 × 10 ⁻³ , and the molar ratio of metal atoms (lithium, magnesium, aluminum, boron) in the activator to chromium atoms in the catalyst is adjusted so as to fall within this range. Is preferred. If the amount ratio of α-olefin to ethylene is less than this range, the resulting ethylene polymer has poor creep resistance, and if it exceeds this range, the rigidity is poor.

An ethylene polymer having an excellent balance between rigidity and creep resistance can be obtained by the above-mentioned catalyst, activator and polymerization method. The melt flow rate suitable for blow molding, especially for large blow molding of gasoline tanks, drums, pallets, etc. (HLMFR indicated by the measurement method used in the following Examples and Comparative Examples) is HL.
MFR = 0.1-20 g / 10 min, preferably 0.5-
18 g / 10 min, more preferably 1.0 to 15 g / 1
0 minutes. The density (the density indicated by the measurement method used in the following Examples and Comparative Examples) is 0.930 to 0.9.
80 g / cm ³ , preferably 0.935 to 0.975 g
/ Cm ³ , more preferably 0.940 to 0.970 g
/ Cm ³ . When the density is out of this range, the balance between rigidity, environmental stress resistance (ESCR) and impact resistance becomes poor. That is, if the density is below this range, the rigidity is excellent, but the environmental stress resistance (ESCR) and impact resistance are low, and the performance of the blow molded product, especially the large blow molded product, is reduced.

[0041]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. [Measurement method] The measurement method used in the examples and comparative examples is shown below. a) Polymer pretreatment for measuring physical properties: Plastograph (Laboplastmill ME25; manufactured by Toyo Seiki Seisaku-sho, Ltd.)
The roller shape was R608 type), and 0.2 wt% of Irganox B225 manufactured by Ciba Geigy was added as an additive, and the mixture was kneaded at 190 ° C. for 7 minutes under nitrogen. b) Melt flow rate: JIS K-7210 (19
According to Table 1 and Condition 7 of the 1996 edition), the measured value at a temperature of 190 ° C. and a load of 21.6 kgf was shown as HLMFR. c) Density: Measured according to JIS K-7112 (1996 version). d) Rigidity: The flexural modulus measured according to JIS K-7203 (1996) was used as the value of rigidity. e) Creep resistance: A circumferential notch tensile creep test (short-term test) was measured according to JIS K-6774 (1996 edition), and the rupture time at a stress of 60 kg / cm ² was defined as creep resistance.

Example 1 (1) Synthesis of Trimethyldiethylsiloxyalane 1.0 m of triethylaluminum manufactured by Tosoh Akzo
ol / liter-hexane solution 44.4 ml at 0-5 ° C
After cooling to 5, the product was manufactured by Shin-Etsu Chemical Co., Ltd.
6 ml (50 mmol) were added dropwise. Then at 25 ° C 3
Stir for 0 minutes and add 1 of trimethyldiethylsiloxyalane.
A 0 mol / liter-hexane solution was obtained. (2) Preparation of catalyst 600 ° C. was placed in a 100 ml flask previously purged with nitrogen.
952 grade silica (specific surface area: 300 m ² / g, pore volume: 1.6 cm ³ /
g, average particle size of 80 μm) and further added 40 ml of n-hexane to form a slurry. STR is added to this slurry.
0.1m of EM 2-ethylhexanoate chromium (III)
ol / liter-hexane solution (1.5 ml, chromium atom carrying amount: 0.20 wt%) was added, and the mixture was stirred at 25 ° C. for 15 minutes. At the end of this time, 0.75 ml of a 1.0 mol / l-hexane solution of isobutylalumoxane manufactured by Tosoh Akzo Co., Ltd. [ratio of (aluminum atoms in alumoxane) / (chromium atoms) = 5.0] was added, and 25 ° C. 3
Stirred for 0 minutes. At the end of this time,
1.0 of trimethyldiethylsiloxyalane synthesized in
0.75 ml of [mol / liter-hexane solution] (ratio of (aluminum atoms in organometallic siloxide) / (chromium atoms) = 5.0] was added, and the mixture was stirred at 25 ° C. for 30 minutes. The solvent was removed under reduced pressure to give a free flowing supported catalyst. The composition of the catalyst is shown in Table 1.

(3) Polymerization 1.5 liters of isobutane and 100 mg of the catalyst prepared in the above (1) were charged into a 3.0 liter autoclave with a stirrer which had been previously replaced with nitrogen. After the temperature of the autoclave was raised to 90 ° C., 1.2 mol of a 0.01 mol / liter-hexane solution of triisobutylaluminum manufactured by Tosoh Akzo (atomic ratio of aluminum / chromium =
3) was introduced under pressure with 14 kg / cm ² of ethylene to initiate polymerization. Ethylene was fed as needed to maintain this ethylene partial pressure. The polymerization temperature was maintained at 90 ° C. for 1 hour by external cooling. When the liquid phase was sampled and analyzed, the concentration of 1-butene in the liquid phase (mol%) / the concentration of ethylene in the liquid phase (mol%) =
1.1 × 10 ⁻³ , 1-hexene concentration in liquid phase (mol
%) / Ethylene concentration (mol%) in liquid phase = 1.4 × 1
It was 0 ^-3 . At the end of this time, the feeding of ethylene was stopped and the polymerization was terminated by releasing ethylene and isobutane out of the system. The yield of white particulate polyethylene is 1
The activity was 1540 g polymer / g catalyst / hour. The measurement results of physical properties are shown in Table 2.

(Embodiment 2) In the embodiment 1 (2), 2
-Instead of chromium (III) ethylhexanoate, 0.1 mol / l of chromium acetylacetonate (manufactured by Wako Pure Chemical Industries, Ltd.)-1.5 ml of a toluene solution (chromium atom carrying amount 0.2
The catalyst was prepared and polymerized in the same manner as in Example 1 except that 0 wt%) was added. At the time of polymerization, the liquid phase was sampled and analyzed. The concentration of 1-butene in the liquid phase (mol%) / the concentration of ethylene in the liquid phase (mol%) =
1.0 × 10 ⁻³ , 1-hexene concentration in liquid phase (mol
%) / Ethylene concentration in liquid phase (mol%) = 1.3 × 1
It was 0 ^-3 . As a result of the polymerization, 166 g of polyethylene was obtained. The activity was 1660 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Example 3 (1) Synthesis of bis (tert-butyl) chromate Synth. Commun. , 10, 905 (198
According to the method described in 0), chromium trioxide and ter
Bis (tert-butyl) chromate was synthesized by reaction with t-butanol. (2) Preparation of catalyst and polymerization In Example 1 (2), chromium 2-ethylhexanoate was used.
Instead of (III), the bis (ter) synthesized in (1) above
1.5 ml of a 0.1 mol / l-hexane solution of t-butyl) chromate (chromium atom carrying amount 0.20 wt
%), And instead of isobutylalumoxane, 0.75 ml of a 1.0 mol / liter-toluene solution of methylalumoxane manufactured by Tosoh Akzo Corporation [aluminum atom in alumoxane] / (chromium atom) = 5. 0]
In addition, instead of trimethyldiethylsiloxyalan,
0.75 ml of a 1.0 mol / liter-hexane solution of diethylaluminum ethoxide manufactured by Tosoh Akzo
[(Aluminum atom in organometallic alkoxide) /
(Chromium atom) = 5.0] except that the catalyst was prepared and polymerized in the same manner as in Example 1. During the polymerization, the liquid phase was sampled and analyzed.
-Butene concentration (mol%) / ethylene concentration in liquid phase (m
ol%) = 1.3 × 10 ⁻³ , 1-hexene concentration in liquid phase (mol%) / ethylene concentration in liquid phase (mol%) =
It was 1.6 × 10 ⁻³ . As a result of the polymerization, 252 g of polyethylene was obtained. The activity was 2520 g polymer / g catalyst /
It was time. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Example 4 (1) Synthesis of bis (triphenylsilyl) chromate According to the method described in US Pat. No. 2,863,891, chromium trioxide and triphenylsilanol were reacted to form bis (triphenylsilanol). Phenylsilyl) chromate was synthesized. (2) Preparation of catalyst and polymerization In Example 1 (2), chromium 2-ethylhexanoate was used.
Instead of (III), 97.7 mg of bis (triphenylsilyl) chromate synthesized in the above (1) (chromium atom carrying amount 0.20 wt%) was added, and instead of isobutylalumoxane, methyl produced by Tosoh Akzo Co., Ltd. 0.75 ml of a 1.0 mol / l toluene solution of alumoxane
[Ratio of (aluminum atom in alumoxane) / (chromium atom) = 5.0] In addition, instead of trimethyldiethylsiloxyalane, a 1.0 mol / liter-hexane solution of diethylaluminum ethoxide manufactured by Tosoh Akzo Co., Ltd. was added. Except for adding 0.75 ml [ratio of (aluminum atom in organometallic alkoxide) / (chromium atom) = 5.0], a catalyst was prepared and polymerization was carried out in the same manner as in Example 1. At the time of polymerization, when the liquid phase was sampled and analyzed, the 1-butene concentration (mol%) in the liquid phase / the ethylene concentration (mol%) in the liquid phase = 1.2 × 10 ⁻³ , 1-hexene concentration (mol%) / ethylene concentration in liquid phase (mol%) = 1.6 × 10 ⁻³ . As a result of the polymerization, 284 g of polyethylene was obtained. Activity is 2840g
Polymer / g catalyst / hour. Table 1 shows the catalyst composition.
Table 2 shows the measurement results of the physical properties.

Example 5 (1) Synthesis of diethylethoxyborane Justus Liebigs Ann. Chem. ,
352 (1975), N, N
-Diethylethoxyborane was synthesized by reacting triethylborane with ethanol using diethylpivalamide as a catalyst. (2) Preparation of catalyst and polymerization In Example 1 (2), chromium 2-ethylhexanoate was used.
Instead of (III), 97.7 mg of bis (triphenylsilyl) chromate synthesized in Example 4 (1) (chromium atom carrying amount: 0.20 wt%) was added, and instead of isobutylalumoxane, Tosoh Akzo 1.0 mol / l-toluene solution of methylalumoxane manufactured by
ml [ratio of (aluminum atom in alumoxidan) / (chromium atom) = 5.0], and instead of trimethyldiethylsiloxyalane, 1.0 mol / l-hexane solution of diethylethoxyborane synthesized in (1) above. Was added in the same manner as in Example 1 except that 0.75 ml [ratio of (boron atom in organometallic alkoxide) / (chromium atom) = 5.0] was added, and polymerization was carried out.
When the liquid phase was sampled and analyzed at the time of polymerization, the concentration of 1-butene in the liquid phase (mol%) / the concentration of ethylene in the liquid phase (mol%) = 0.9 × 10 ⁻³ , Hexene concentration (mol%) / ethylene concentration in liquid phase (mol
%) = 1.3 × 10 ⁻³ . 262 g as a result of polymerization
Of polyethylene was obtained. Activity is 2620 g polymer / g
Catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

(Example 6) In Example 4, 0.01 mol of triisobutylaluminum added at the time of polymerization was used.
Example 4 except that the amount of the hexane solution per liter / liter was 2.4 ml (aluminum / chromium molar ratio = 6).
A catalyst was prepared and polymerized in the same manner as described above. During the polymerization, the liquid phase was sampled and analyzed.
Butene concentration (mol%) / Ethylene concentration in liquid phase (mo
1%) = 2.6 × 10 ⁻³ , 1-hexene concentration in liquid phase (mol%) / ethylene concentration in liquid phase (mol%) =
It was 3.5 × 10 ⁻³ . As a result of the polymerization, 290 g of polyethylene was obtained. The activity was 2900 g polymer / g catalyst /
It was time. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Example 7 A catalyst was prepared in the same manner as in Example 4 except that hydrogen was introduced at a partial pressure of 0.5 kg / cm ² and the polymerization temperature was changed to 85 ° C. ,
Polymerization was performed. When the liquid phase was sampled and analyzed during the polymerization, the concentration of 1-butene in the liquid phase (mol%) / the concentration of ethylene in the liquid phase (mol%) = 1.5 × 10 ⁻³ and 1 in the liquid phase -Hexene concentration (mol%) / ethylene concentration in liquid phase (mol%) = 1.8 x ^10-3 . As a result of the polymerization, 267 g of polyethylene was obtained. Activity is 2670
g polymer / g catalyst / hour. Table 1 shows the catalyst composition.
Table 2 shows the measurement results of the physical properties.

Example 8 (Vapor phase polymerization) Eur. Polym. J. , Vol. 2
1,245 (1985), a vertical vibratory reactor (capacity 15) resembling a fluidized bed reactor.
0 cm ³ , diameter 50 mm, vibration speed 420 times / min (7H
z), a vibration distance of 6 cm) was made, and gas phase polymerization was performed. In a reactor previously purged with nitrogen, 50 mg of the catalyst obtained in the same manner as in Example 4 was put in an ampoule under a nitrogen atmosphere, and then 0.01 mol / liter-hexane solution of triisobutylaluminum 0 manufactured by Tosoh Akzo was added. .6
ml (aluminum / chromium molar ratio = 3), and 90
After heating to 0 ° C, the polymerization was started by pressurizing with 14 kg / cm ² of ethylene and breaking the ampoule by vibration. In order to maintain the pressure of ethylene in the reactor, ethylene was supplied as needed via a flexible joint. After the polymerization reaction was performed at 94 ° C. for 1 hour, ethylene feeding was stopped, the reactor was cooled to room temperature, degassed, and the contents were taken out. When the gas phase was sampled and analyzed at the time of degassing, the 1-butene concentration (mol
%) / Ethylene concentration (mol%) in gas phase = 0.9 × 1
0 ⁻³ , the concentration of 1-hexene in the gas phase (mol%) / the concentration of ethylene in the gas phase (mol%) = 1.2 × 10 ⁻³ . The yield of white particulate polyethylene was 36 g and the activity was 720 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Comparative Example 1 Polymerization was carried out in the same manner as in Example 1 except that triisobutylaluminum was not added during the polymerization. When the liquid phase was sampled and analyzed during the polymerization, 1-butene, 1
Α-olefins such as hexene were not detected. As a result of the polymerization, 150 g of polyethylene was obtained. Activity is 15
00 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2. Comparative Example 2 Polymerization was carried out in the same manner as in Example 2 except that triisobutylaluminum was not added during the polymerization. During the polymerization, the liquid phase was sampled and analyzed, and no α-olefins such as 1-butene and 1-hexene were detected in the liquid phase. As a result of polymerization, 1
60 g of polyethylene were obtained. The activity was 1600 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Comparative Example 3 Polymerization was carried out in the same manner as in Example 3 except that triisobutylaluminum was not added during the polymerization. When the liquid phase was sampled and analyzed during the polymerization, 1-butene, 1
Α-olefins such as hexene were not detected. As a result of the polymerization, 250 g of polyethylene was obtained. 25 active
00 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2. Comparative Example 4 Polymerization was carried out in the same manner as in Example 4 except that triisobutylaluminum was not added during the polymerization. When the liquid phase was sampled and analyzed during the polymerization, α-olefins such as 1-butene and 1-hexene were not detected in the liquid phase. As a result of polymerization, 2
82 g of polyethylene were obtained. The activity was 2820 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 5, except that triisobutylaluminum was not added during the polymerization. When the liquid phase was sampled and analyzed during the polymerization, 1-butene, 1
Α-olefins such as hexene were not detected. As a result of the polymerization, 261 g of polyethylene was obtained. Activity is 26
10 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2. Comparative Example 6 A gas phase polymerization was carried out in the same manner as in Example 8, except that triisobutylaluminum was not added during the polymerization. After the polymerization, the gas phase was sampled and analyzed. As a result, α-olefins such as 1-butene and 1-hexene were not detected in the gas phase. As a result of the polymerization, 35 g of polyethylene was obtained. The activity was 700 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

Comparative Example 7 A catalyst was prepared in the same manner as in Example 3 except that no isobutylalumoxane was added during the preparation of the catalyst, and polymerization was carried out in the same manner as in Example 1. . When the liquid phase was sampled and analyzed during the polymerization, the 1-butene concentration (mol%) in the liquid phase was analyzed.
/ Ethylene concentration (mol%) in liquid phase = 5.7 × 1
0 ⁻⁴ , the concentration of 1-hexene in the liquid phase (mol%) / the concentration of ethylene in the liquid phase (mol%) = 7.3 × 10 ⁻⁴ . As a result of the polymerization, 45 g of polyethylene was obtained. The activity was 450 g polymer / g catalyst / hour. The composition of the catalyst is shown in Table 1, and the measurement results of physical properties are shown in Table 2.

[0055]

The ethylene polymer produced by polymerizing ethylene or copolymerizing ethylene with an α-olefin using the novel chromium polymerization catalyst of the present invention is:
While maintaining high rigidity without lowering the stiffness, it is a greatly improved creep resistance, an ethylene polymer excellent in balance between stiffness and creep resistance, and can be efficiently produced by the method of the present invention. Worthwhile, industrially. The ethylene-based polymer obtained in the present invention is suitable for blow and the like, particularly for large blow.

[Brief description of the drawings]

FIG. 1 is a flowchart for preparing a catalyst used in the present invention.

[Table 1]

[Table 2]

Claims (11)

[Claims] (1) Chromium carboxylate, chromium-1,
Using a chromium compound having an organic group selected from a 3-diketo compound, a chromate ester and a chromamide compound, an alumoxane, an organometallic alkoxide and / or an organometallic siloxide on a carrier, and (2) an activator A method for producing an ethylene-based polymer, comprising: (1) Chromium carboxylate, chromium-1,
A catalyst supporting an alumoxane, an organometallic alkoxide and / or an organometallic siloxide after supporting a chromium compound having an organic group selected from a 3-diketo compound, a chromate ester and a chromamide compound on a carrier, and (2) an activator The method for producing an ethylene-based polymer according to claim 1, wherein: 3. The method for producing an ethylene-based polymer according to claim 1, wherein the polymerization is carried out after contacting the activator with the catalyst in the presence or absence of ethylene. 4. The component supported on the carrier has a ratio of (aluminum atom in alumoxane) / (chromium atom in chromium compound) of 0.5 to 100, and (organometallic alkoxide and / or organometallic siloxide). The ratio of (metal atoms in the metal) / (chromium atoms in the chromium compound) is 0.5 to 100, and (aluminum atoms in the alumoxane) / (metal atoms in the organometallic alkoxide and / or organometallic siloxide) The ratio is 0.01 to 1
The method for producing an ethylene-based polymer according to any one of claims 1 to 3, which is a catalyst of No. 00. 5. The method according to claim 1, wherein the carrier is an inorganic metal oxide (solid acid or Lewis acid) and / or an inorganic halide. 6. The carrier has a specific surface area of 50 to 1000 m ² /
g, the pore volume is 0.5 to 3.0 cm ³ / g, and the average particle size is 10 to 200 μm.
The method for producing an ethylene-based polymer according to claim 5, wherein the catalyst is 5.0 wt% supported catalyst. 7. The method for producing an ethylene-based polymer according to claim 1, wherein the alumoxane is an alkylalumoxane. 8. The ethylene-based polymer according to claim 1, wherein the organometallic alkoxide and / or organometallic siloxide is an organometallic alkoxide and / or organometallic siloxide of Group 2 or 13 of the periodic table. Manufacturing method of coalescence. 9. The method according to claim 8, wherein the organometallic alkoxide and / or the organometallic siloxide is selected from organoaluminum alkoxides, organoaluminum siloxides, organomagnesium alkoxides, and organoboron alkoxides. 10. The method according to claim 1, wherein the activator is selected from an organic lithium compound, an organic magnesium compound, an organic aluminum compound, and an organic boron compound. 11. The activator is an alkyl lithium compound,
The method for producing an ethylene-based polymer according to claim 10, which is selected from a dialkylmagnesium compound, a trialkylaluminum compound, and a trialkylboron compound.