JP2571280B2 - Ethylene copolymer and method for producing the same - Google Patents

Description

Description TECHNICAL FIELD [0001] The present invention relates to a novel ethylene-based copolymer and a method for producing the same, and more particularly, to a molecular weight distribution (w / n) as compared with a conventionally known ethylene-based copolymer. The present invention relates to a novel ethylene-based copolymer having excellent polymer fluidity despite its narrow width and a method for producing the same.

Technical Background of the Invention A copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms (hereinafter referred to as an ethylene-based copolymer) is produced by molding into a film or the like as compared with a conventional high-pressure low-density polyethylene. It is excellent in mechanical strength such as tensile strength, tear strength or impact strength, and is also excellent in heat resistance, stress crack resistance, optical properties, heat sealability, etc., and is particularly suitable as a material for an inflation film.

The ethylene-based copolymer as described above generally has a ratio (w / w) of the weight average molecular weight (w) to the number average molecular weight (n).
As the molecular weight distribution represented by n) becomes narrower, a molded article such as a film obtained from the ethylene-based copolymer has excellent properties such as less stickiness. However, when the ethylene copolymer has a narrow molecular weight distribution as described above, when this copolymer is melted, MFR ₁₀ at a load of 10 kg at 190 ° C. and MFR ₂ at a load of 2.16 kg are different. There is a problem that the fluidity represented by the ratio (MFR ₁₀ / MFR ₂ ) is small and the moldability is poor.

For this reason, if w / n is small and the molecular weight distribution is narrow,
In addition, if an ethylene copolymer having a large MFR ₁₀ / MFR ₂ and excellent fluidity appears, its industrial value is extremely large.

Conventionally, to produce an ethylene copolymer, an olefin polymerization catalyst comprising a titanium or vanadium compound and an organoaluminum compound has been used.In recent years, zirconium compounds and aluminoxane have been used as new Ziegler-type olefin polymerization catalysts. A catalyst consisting of has recently been proposed.

JP-A-58-19309 discloses that the following formula (cyclopentadienyl) ₂ MeRHal [where R is cyclopentadienyl, C ₁ -C ₆ alkyl and halogen, and Me is a transition metal , Hal is a halogen], a compound represented by the following formula: Al ₂ OR ₄ (Al (R) —O) _n [where R is methyl or ethyl, and n is 4 to 20]
Or a linear aluminoxane represented by the following formula: In the presence of a catalyst comprising a cyclic aluminoxane represented by the formula: wherein R and n are the same as defined above, one or more of ethylene and a C _{3 to} C ₁₂ α-olefin may be used. A method of polymerizing at a temperature of -50C to 200C is described. The publication states that in order to adjust the density of the resulting polyethylene, the polymerization of ethylene should be carried out in the presence of small amounts of up to 10% by weight of somewhat longer-chain α-olefins or mixtures. .

JP-A-59-95292 discloses the following formula: [Where n is 2 to 40, R is C _{1 to} C ₆ ] and a linear aluminoxane represented by the following formula: [Wherein the definitions of n and R are the same as described above], the invention relating to a method for producing a cyclic aluminoxane represented by the formula: The publication discloses that, for example, a mixture of methylaluminoxane and a bis (cyclopentadienyl) compound of titanium or zirconium produced by the same production method and polymerizing an olefin gives 1 g of transition metal and It is stated that over 25 million g of polyethylene are obtained per hour.

JP-A-60-35005 discloses the following formula: Wherein R ¹ is C ₁ -C ₁₀ alkyl and R ⁰ is R ¹ or is bonded to and represents —O—. The aluminoxane compound represented by the formula A method is disclosed for producing a olefin polymerization catalyst by chlorinating the reaction product and treating it with a compound of Ti, V, Zr or Cr. The same publication, the catalyst is described as being particularly suitable for the copolymerization of mixtures of α- olefins of ethylene and C ₃ -C _12.

JP-A-60-35006 discloses, as a catalyst system for producing a reactor blend polymer, mono-, di- or tri-cyclopentadienyl of two or more different transition metals or a derivative (a) thereof and alumino. Combinations of xane (b) are disclosed. Example 1 of the publication discloses that ethylene and propylene are polymerized using bis (pentamethylcyclopentadienyl) zirconium dimethyl and aluminoxane as catalysts to obtain a number average molecular weight of 15,300 and a weight average molecular weight of
It is disclosed that a polyethylene containing 36,400 and 3.4% of a propylene component was obtained. In Example 2, bis (pentamethylcyclopentadienyl) zirconium dichloride, and bis (methylcyclopentadienyl) zirconium dichloride and aluminoxane as catalysts were used to polymerize ethylene and propylene to obtain a number average molecular weight of 2,200. Toluene soluble part containing propylene component with weight average molecular weight of 11,900 and 30 mol% and number average molecular weight
3,000, weight average molecular weight 7,400 and number average molecular weight consisting of toluene insoluble part containing 4.8 mol% propylene component
A blend of polyethylene and an ethylene / propylene copolymer containing 2,000, a propylene component having a weight average molecular weight of 8,300 and 7.1 mol% is obtained. Similarly, in Example 3, a molecular weight distribution (w / n) of 4.57 and a propylene component 2
LLDPE consisting of a soluble portion of 0.6%, a molecular weight distribution of 3.04 and an insoluble portion of 2.9 mol% of propylene component and ethylene-
Blends of propylene copolymers are described.

JP-A-60-35007 discloses that ethylene alone or a metallocene together with an α-olefin having 3 or more carbon atoms has the following formula: [Where R is an alkyl group having 1 to 5 carbon atoms, and n is an integer of 1 to about 20] or a cyclic aluminoxane represented by the following formula: [Where the definitions of R and n are the same as described above] and a method of polymerizing in the presence of a catalyst system containing a linear aluminoxane represented by the formula: According to the publication, the polymer obtained by the method has a weight average molecular weight of about 500 to about 1.4 million and a molecular weight distribution of 1.5 to 4.0.

JP-A-60-35008 discloses that a catalyst having at least two kinds of metallocenes and aluminoxane is used to obtain polyethylene having a wide molecular weight distribution or ethylene and an α-olefin of C _{3 to} C ₁₀ . Is described as being produced. The publication describes that the copolymer has a molecular weight distribution (w / n) of 2 to 50.

JP-A-61-130314 discloses that, when propylene is polymerized in the presence of a catalyst system comprising a sterically fixed zircon-chelate compound and aluminoxane, a polypropylene having a high isotacticity can be obtained. Have been described.

Further, J. Am. Chem. Soc., 109, 6544 (1987) states that when propylene is polymerized in the presence of a catalyst system comprising ethylenebis (indenyl) hafnium dichloride or its hydride and aluminoxane, a high molecular weight is obtained. Of isotactic polypropylene and its molecular weight distribution (w /
It is described that n) is as narrow as 2.1 to 2.4.

On the other hand, Japanese Patent Application Laid-Open No. 63-142005 discloses that a catalyst system comprising tetramethylethylenebis (cyclopentadienyl) titanium chloride and aluminoxane contains w / n
It is described that a stereoblock polypropylene having a particle size of 5.0 to 14.9 can be obtained. The propylene obtained here is a rubbery polymer having a short isotactic chain length.

The present inventors have found that if ethylene and an α-olefin having 3 to 20 carbon atoms are copolymerized in the presence of an olefin polymerization catalyst comprising a specific hafnium compound and an organic aluminum oxy compound, w / n is small. Narrow molecular weight distribution,
In addition, they have found that an ethylene copolymer having a large MFR ₁₀ / MFR ₂ and excellent fluidity can be obtained, thereby completing the present invention.

An object of the present invention is to solve the problems in the prior art as described above, and has a small w / n and a narrow molecular weight distribution, and has a large MFR ₁₀ / MFR ₂ and excellent fluidity. It is an object of the present invention to provide such an ethylene-based copolymer and a method for producing the same.

SUMMARY OF THE INVENTION The ethylene-based copolymer according to the present invention comprises 60 to 96 mol% of a structural unit (a) derived from ethylene and 3 to 20 carbon atoms.
(B) an ethylene copolymer comprising 4 to 40 mol% of a structural unit (b) derived from an α-olefin, wherein (A) the ethylene copolymer has a density of 0.85 to 0.92 g / cm
Is ^3, the (B) an intrinsic viscosity, measured in a 135 ° C. decalin [eta]
(C) the ratio (w / n) of the weight average molecular weight (w) to the number average molecular weight (n) measured by GPC is in the range of 1.2 to 4, and (D) The ratio of MFR ₁₀ at a load of 10 kg at 190 ° C. to MFR ₂ at a load of 2.16 kg (MFR ₁₀ / MFR ₂ ) is in the range of 8 to 50.

Further, the method for producing an ethylene copolymer according to the present invention comprises: (A) coordinating a polydentate compound in which at least two groups selected from an indenyl group or a substituent thereof are bonded via a lower alkylene group; And a hafnium catalyst component obtained by treating the hafnium compound with silica gel obtained by treating the hafnium compound with an alkylsilylated silica gel, and (B) a catalyst formed from an organoaluminum oxy compound. ~
An α-olefin having 20 and a structural unit (a) derived from ethylene in an amount of 60 to 96 mol% and an α-olefin having 3 to 20 carbon atoms
The intrinsic viscosity, measured in decalin at 135 ° C., containing 4 to 40 mol% of structural units (b) derived from olefins and copolymerized to a density of 0.85 to 0.92 g / cm ³ [Η] is in the range of 0.1 to 10 dl / g, the ratio (w / n) of the weight average molecular weight (w) and the number average molecular weight (n) measured by GPC is in the range of 1.2 to 4, and 190 ° C. The method is characterized in that an ethylene copolymer having a ratio (MFR ₁₀ / MFR ₂ ) of MFR ₁₀ at a load of 10 kg and MFR ₂ at a load of 2.16 kg in the range of 8 to 50 is produced.

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the ethylene copolymer according to the present invention and a method for producing the same will be described in detail.

FIG. 1 is an explanatory view of the production process of the ethylene copolymer according to the present invention.

The ethylene copolymer according to the present invention is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. In this ethylene-based copolymer, the density is 0.85-0.5.
92 g / cm ^3, preferably 0.85~0.91g / cm ^3, more preferably
Is a 0.85~0.90g / cm ^3.

The density was measured with a density gradient tube using a strand obtained at the time of MFR ₂ measurement at 190 ° C. under a load of 2.16 kg.
In this ethylene-based copolymer, the structural unit (a) derived from ethylene is 60 to 96 mol%, preferably 65 to 96 mol%.
Present in an amount of 95 mol%, more preferably 70-94 mol%,
The structural unit (b) derived from an α-olefin having 3 to 20 carbon atoms is 4 to 40 mol%, preferably 5 to 35 mol%,
More preferably, it is present in an amount of 6 to 30 mol%.

The composition of the copolymer is usually about 10 mmφ in a sample tube.
The ¹³ C-NMR spectrum of a sample in which 200 mg of the copolymer was uniformly dissolved in 1 ml of hexachlorobutadiene was measured at a measurement temperature.
It is measured and determined under the conditions of 120 ° C., measurement frequency 25.05 MHz, spectrum width 1500 Hz, pulse repetition time 4.2 sec, and pulse width 6 usec.

As the α-olefin having 3 to 20 carbon atoms used in the present invention, propylene, 1-butene, 1-pentene, 1-
Hexene, 4-methyl-1-pentene, 1-octene,
1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like are used.

In addition, the ethylene copolymer according to the present invention preferably has an intrinsic viscosity [η] measured in decalin at 135 ° C. of 0.1 to 10 dl / g, preferably 0.5 to 6 dl / g.

Further, the molecular weight distribution (w / n) of the ethylene copolymer according to the present invention determined by gel permeation chromatography (GPC) is in the range of 1.2 to 4, preferably 1.4 to 3.5, more preferably 1.5 to 3.0. is there. Thus, the ethylene copolymer according to the present invention has a narrow molecular weight distribution and excellent blocking resistance.

The w / n values were determined as follows based on "Gel Permeation Chromatography" published by Takeuchi and published by Maruzen.

(1) Using standard polystyrene having a known molecular weight (monodisperse polystyrene, manufactured by Toyo Soda Co., Ltd.)
And its GPC (Gel Permeation Chromatograph) count are measured, and a correlation curve calibration curve between the molecular weight M and the EV (Elution Volume) is prepared. The concentration at this time is 0.02% by weight.

(2) GPC chromatograph of the sample by GPC measurement,
According to the above (1), the number average molecular weight w and the weight average molecular weight w in terms of polystyrene are calculated, and the w / n value is obtained. The sample preparation conditions and GPC measurement conditions at that time are as follows.

[Sample preparation] (A) A sample is dispersed in an Erlenmeyer flask together with an o-dichlorobenzene solvent so as to be 0.1% by weight.

(B) Heat the Erlenmeyer flask to 140 ° C. and stir for about 30 minutes to dissolve.

(C) Apply the solution to GPC.

[GPC Measurement Conditions] The measurement was performed under the following conditions.

(A) Equipment Waters (150C-ALC / GPC) (b) Column Toyo Soda (GMH type) (c) Sample volume 400μl (d) Temperature 140 ° C (e) Flow rate 1ml / min Also ethylene according to the present invention The system copolymer has a ratio of MFR ₁₀ at a load of 10 kg at 190 ° C. and MFR ₂ at a load of 2.16 kg (MFR ₁₀ / MFR ₂ ) of 8 to 50, preferably 8.5 to 45, more preferably 9 to 45. In the range of 40.

As described above, the ethylene copolymer having MFR ₁₀ / MFR ₂ in the range of 8 to 50 has extremely good fluidity when the polymer is melted.

On the other hand, a conventionally known ethylene copolymer having a w / n of 1.2 to 4 has a MFR ₁₀ / MFR ₂ as described above.
Is in the range of 4 to 7, and the polymer is inferior in fluidity at the time of melting.

As described above, the ethylene copolymer according to the present invention has excellent properties such as a low molecular weight distribution (w / n) and a low stickiness of the molded product, and has an MFR ₁₀ / M
FR ₂ is large and has excellent moldability when polymer is melted.

The ethylene copolymer according to the present invention as described above comprises: (A) coordinating a polydentate compound in which at least two groups selected from an indenyl group or a substituent thereof are bonded via a lower alkylene group; And a hafnium catalyst component obtained by treating the hafnium compound with silica gel obtained by treating the hafnium compound with an alkylsilylated silica gel, and (B) a catalyst formed from an organoaluminum oxy compound. ~
An α-olefin having 20 and a structural unit (a) derived from ethylene in an amount of 60 to 96 mol% and an α-olefin having 3 to 20 carbon atoms
- the constituent units derived from the olefin (b) in an amount of 4 to 40 mol%, and density can be produced by copolymerizing such a 0.85~0.92g / cm ^3.

The catalyst component [A] used in the present invention is an indenyl group or a substituted product thereof, specifically, an indenyl group,
A hafnium compound having as a ligand a polydentate compound in which at least two groups selected from the group consisting of a substituted indenyl group and a partial hydride thereof are bonded via a lower alkylene group; It is a compound obtained by treating with activated silica gel.

The following compounds can be exemplified as the hafnium compound.

Ethylene bis (indenyl) dimethyl hafnium, ethylene bis (indenyl) diethyl hafnium, ethylene bis (indenyl) diphenyl hafnium, ethylene bis (indenyl) methyl hafnium monochloride, ethylene bis (indenyl) ethyl hafnium monochloride, ethylene bis (indenyl) methyl Hafnium monobromide, ethylenebis (indenyl) hafnium dichloride, ethylenebis (indenyl) hafnium dibromide, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) dimethylhafnium, ethylenebis (4,5,6, 7-tetrahydro-1-indenyl) methylhafnium monochloride, ethylenebis (4,5,6,7-tetrahydro-1-indenyl) hafnium dichloride, ethylenebis (4,5,6,7-tetrahydride -1-indenyl) hafnium dibromide, ethylenebis (4-methyl-1-indenyl) hafnium dichloride, ethylenebis (5-methyl-1-indenyl) hafnium dichloride, ethylenebis (6-methyl-1-indenyl) hafnium dichloride Ethylenebis (7-methyl-1-indenyl) hafnium dichloride, ethylenebis (5-methoxy-1-indenyl) hafnium dichloride, ethylenebis (2,3-dimethyl-1-indenyl) hafnium dichloride, ethylenebis (4, 7-dimethyl-1-indenyl) hafnium dichloride, ethylenebis (4,7-dimethoxy-1-indenyl)
Hafnium dichloride.

The hafnium compound may contain a small amount of zirconium or titanium. that time,
The content is 1% by weight or less, preferably 0.7% by weight or less, more preferably 0.5% by weight or less.

Further, as the hafnium catalyst component according to the present invention, a compound obtained by treating the above hafnium compound with alkylsilylated silica gel can be used. More specifically, as the hafnium catalyst component used in the present invention, for example, a hafnium compound solution obtained by dissolving a hafnium compound as described above in an organic solvent such as toluene, a column packed with silica gel alkylsilylated. To contact the hafnium compound solution and the alkylsilylated silica gel,
The outflowing hafnium compound solution can be used.

As the organic solvent, aromatic hydrocarbons such as toluene, benzene, and xylene are preferably used. As the alkylsilylated silica gel, silica gel is dimethyldichlorosilane, ethylmethyldichlorosilane,
What is obtained by treating with trimethylchlorosilane, trimethylbromosilane, divinyldichlorosilane, diethyldichlorosilane, methylpropyldichlorosilane, or the like is used. The hafnium compound solution usually has a hafnium concentration of 1 × 10 ^{−5 to} 5 × 10 ⁻³ mol / l, and the alkylsilylated silica gel is usually used in an amount of 20 to 500 g per 1 mmol of the hafnium compound. The contact temperature between the hafnium compound solution and the alkylsilylated silica gel is usually in the range of 0 to 50 ° C.

As the catalyst component (A), when a hafnium catalyst component obtained by treating the above hafnium compound with an alkylsilylated silica gel is used, an ethylene copolymer excellent in transparency can be obtained.

The catalyst component [B] used in the method of the present invention comprises:
It is an organic aluminum oxy compound. General formula (I) and general formula (II) as an organoaluminum oxy compound used as a catalyst component The benzene-soluble aluminoxane represented by the following formula can be exemplified. In the aluminoxane, R may be the same or different and is a hydrocarbon group such as a methyl group, an ethyl group, a propyl group and a butyl group, preferably a methyl group, an ethyl group, particularly preferably a methyl group. , M is an integer of 2 or more, preferably 5 or more. As a method for producing the aluminoxane, for example, the following method can be exemplified.

(1) Compounds containing water of adsorption, salts containing water of crystallization such as magnesium chloride hydrate, copper sulfate hydrate,
A method in which a trialkylaluminum is added to a hydrocarbon medium suspension such as aluminum sulfate hydrate, nickel sulfate hydrate, cerous chloride hydrate and the like to cause a reaction.

(2) A method in which water, steam or ice is allowed to act directly on a trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran.

The aluminoxane may contain a small amount of an organic metal component.

Further, as the organoaluminum oxy compound used in the present invention, a benzene-insoluble organoaluminum oxy compound can be exemplified. The benzene-insoluble organic aluminum oxy compound will be described below.

The benzene-insoluble organoaluminum oxy compound used in the present invention can be obtained by reacting (i) a reaction between an organoaluminum compound and water, or a reaction of an aluminoxane solution, for example, a hydrocarbon solution with water or (ii) an active hydrogen-containing compound. Obtained by

This benzene-insoluble organoaluminum oxy compound is [Wherein, R ¹ is a hydrocarbon group having 1 to 12 carbon atoms], and the Al component soluble in benzene at 60 ° C. is 10% or less in terms of Al atoms. , Preferably 5% or less, particularly preferably 2% or less, and is insoluble or hardly soluble in benzene.

The solubility of the organoaluminum oxy compound according to the present invention was determined by suspending the organoaluminum oxy compound corresponding to 100 milligram atoms of Al in 100 ml of benzene, mixing the mixture at 60 ° C. for 6 hours with stirring, and attaching a jacket. G-
5 Using a glass filter, perform hot filtration at 60 ° C, and separate the solid part separated on the filter from benzene at 60 ° C.
After washing four times with 50 ml, the Al present in the total filtrate was
It is determined by measuring the abundance of atoms (x mol mol) (x%).

In the above alkyloxyaluminum unit, R ¹
Is specifically exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, pentyl, hexyl, octyl, decyl, cyclohexyl, cyclooctyl, etc. it can. Of these, a methyl group and an ethyl group are preferable, and a methyl group is particularly preferable.

The benzene-insoluble organoaluminum oxy compound according to the present invention has the formula In addition to the alkyloxyaluminum unit represented by Wherein R ¹ is the same as above, and R ² is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 6 to 20 carbon atoms. , Hydroxyl, halogen or hydrogen, R ¹ and R ²
Represents different groups from each other]. In that case, the alkyloxyaluminum unit Is preferably 30 mol% or more, preferably 50 mol% or more, particularly preferably 70 mol% or more.

(I) The organoaluminum compound used for producing such a benzene-insoluble organoaluminum oxy compound is R ¹ _n AlX _3-n (wherein R ¹ has 1 to 12 carbon atoms)
X is a halogen, an alkoxy group having 1 to 12 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, or hydrogen, and n is 2 to 3).

Such (i) organoaluminum compounds include:
Specifically, trimethyl aluminum, triethyl aluminum, tripropyl aluminum, triisopropyl aluminum, tri _n -butyl aluminum, tri
_sec - butyl aluminum, tri _tert - butyl aluminum, tripentyl aluminum, tri-hexyl aluminum, tri-octyl aluminum, tridecyl aluminum, tricyclohexyl aluminum, trialkyl aluminum such as tri-cyclooctyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, diethyl Dialkylaluminum halides such as aluminum bromide and diisobutylaluminum chloride; dialkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride; dialkylaluminum alkoxides such as dimethylaluminum methoxide and diethylaluminum ethoxide; and dialkylaluminum alkoxides such as diethylaluminum phenoxide Such as Le Kill aluminum arylene Loki Sid is used. Among these organoaluminum compounds, an organoaluminum compound in which R is an alkyl group and X is a chlorine atom in the above general formula is preferable, and a trialkylaluminum is particularly preferable.

Further, in the (i) an organoaluminum compound represented by the general formula _{(i-C 4 H 9)} x Al y (C 5 H 10) z (x, y, z are each a positive number, the z ≧ 2x) The represented isoprenyl aluminum can also be used.

The (a) organoaluminum compound as described above is used alone or in combination.

In addition, as the (ii) active hydrogen-containing compound used in producing the benzene-insoluble organic aluminum oxy compound according to the present invention, alcohols such as methyl alcohol and ethyl alcohol, and diols such as ethylene glycol and hydroquinone are used. .

In the present invention, when water is used in preparing the benzene-insoluble organic aluminum oxy compound, the water is dissolved in a hydrocarbon solvent such as benzene, toluene, and hexane, an ether solvent such as tetrahydrofuran, and an amine solvent such as triethylamine. Alternatively, they can be used dispersed or in the form of water vapor or water. In addition, as water, crystallization water of salts such as magnesium chloride, magnesium sulfate, aluminum sulfate, copper sulfate, nickel sulfate, iron sulfate, cerous chloride, etc., or inorganic compounds or polymers such as silica, alumina, aluminum hydroxide and the like are adsorbed. Adsorbed water or the like can also be used.

As described above, the benzene-insoluble organoaluminum oxy compound according to the present invention includes (i) a reaction between an organoaluminum compound and water, or an aluminoxane solution,
For example, it is obtained by reacting a hydrocarbon solution with water or (ii) an active hydrogen-containing compound. In order to produce a benzene-insoluble organoaluminum oxy compound from (i) an organoaluminum compound and water, (i) contacting the (a) organoaluminum compound with water in a solvent, for example, a hydrocarbon solvent, Water may be added to the reaction system such that the amount of dissolved organic aluminum atoms in the solution is 20% or less of the total organic aluminum atoms. In order to obtain a benzene-insoluble organoaluminum oxy compound in this manner, it is desirable to contact water in an amount of 1 to 5 mol, preferably 1.5 to 3 mol, per 1 mol of the (a) organoaluminum compound.

The reaction for producing the benzene-insoluble organoaluminum oxy compound as described above is performed in a solvent, for example, a hydrocarbon solvent. Examples of the solvent include benzene, toluene, xylene, cumene, and aromatic hydrocarbons such as cumene.
Butane, isobutane, pentane, hexane, octane,
Aliphatic hydrocarbons such as decane, dodecane, hexadecane and octadecane; alicyclic hydrocarbons such as cyclopentane, cyclooctane, cyclodecane and cyclododecane; hydrocarbon solvents such as petroleum fractions such as gasoline, kerosene and light oil, or the above It is also possible to use halides of aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons, especially halogenated hydrocarbons such as chlorinated products and brominated products, and ethers such as ethyl ether and tetrahydrofuran.
Among these hydrocarbon media, aromatic hydrocarbons are particularly preferred.

The concentration of the organoaluminum compound in the reaction system is preferably in the range of 1 × 10 ^{−3 to} 5 g atoms / l, preferably 1 × 10 ^{−2 to} 3 g atoms / l in terms of aluminum atoms. The concentration of water such as water of crystallization in the reaction system is usually 1 ×
It is desirably in the range of 10 ^{−3 to} 20 mol / l, preferably 1 × 10 ⁻² to 10 mol / l. At this time, the amount of organic aluminum atoms dissolved in the reaction system is 20% or less, preferably 10% or less, more preferably 0% or less based on all the organic aluminum atoms.
It is desirable to be in the range of ５5%.

(I) The contact between the organoaluminum compound and water may be specifically performed as follows.

(1) (i) A method in which a hydrocarbon solution of organoaluminum is brought into contact with a hydrocarbon solvent containing water.

(2) A method in which (i) the organic aluminum is brought into contact with the water vapor by, for example, blowing water vapor into a hydrocarbon solution of the organic aluminum.

(3) (i) mixing a hydrocarbon solution of an organoaluminum with a hydrocarbon suspension of a compound containing adsorbed water or a compound containing water of crystallization, and bringing (i) the organoaluminum into contact with the adsorbed water or the water of crystallization. Method.

(4) (i) A method of bringing a hydrocarbon solution of an organoaluminum into contact with ice.

The contact reaction between (i) the organoaluminum compound and water as described above is usually performed at -100 to 150C, preferably -50 to 100C.
More preferably, the reaction is performed at a temperature of -30 to 80C. The reaction time varies greatly depending on the reaction temperature, but is usually about 1 to 200 hours, preferably about 2 to 100 hours.

The benzene-insoluble organoaluminum oxy compound according to the present invention is prepared by mixing a solution of aluminoxane with water or (i
i) To prepare from an active hydrogen-containing compound, aluminoxane in a solution of aluminoxane and water or (i
i) The active hydrogen-containing compound may be brought into contact.

The solution of aluminoxane is dissolved in a solvent such as that used for producing the benzene-insoluble organic aluminum oxy compound as described above, preferably in an aromatic hydrocarbon such as benzene or toluene. Although the solution is prepared, it may contain other components as long as the reaction between the aluminoxane and water or the active hydrogen-containing compound is not adversely affected.

Water or (ii) an active hydrogen-containing compound used in the catalytic reaction is aluminum 1 in a solution of aluminoxane.
It is used in an amount of 0.1 to 5 mol, preferably 0.2 to 3 mol, per gram atom. The concentration in the reaction system is usually in the range of 1 × 10 ^{−3 to} 5 g atoms / l, preferably 1 × 10 ^{−2 to} 3 g atoms / l in terms of aluminum atoms. The concentration of water inside is usually 2 × 10 ^{-4 to} 5 mol
/ l, preferably 2 × 10 ^{-3 to} 3 mol / l.

In order to contact the solvent of aluminoxane as described above with water or (ii) an active hydrogen-containing compound, a contact reaction between an aluminoxane solution and water will be described as an example. What should I do?

(1) A method of contacting a solution of aluminoxane with a hydrocarbon solvent containing water.

(2) A method of contacting the aluminoxane in the aluminoxane solution with the steam by, for example, blowing steam into the aluminoxane solution.

(3) mixing a solution of aluminoxane with a hydrocarbon suspension of a compound containing absorbed water or a compound containing water of crystallization,
A method in which aluminoxane in an aluminoxane solution is brought into contact with adsorbed water or crystal water.

(4) A method of bringing a solution of aluminoxane into direct contact with water or ice.

(Ii) When an active hydrogen-containing compound is used, the same can be applied as described above.

The contact reaction between the aluminoxane solution as described above and water or (ii) an active hydrogen-containing compound is usually carried out in the range of -50 to
150 ° C, preferably 0 to 120 ° C, more preferably 20 to 100 ° C
At a temperature of The reaction time varies greatly depending on the reaction temperature, but is usually 0.5 to 300 hours, preferably 1 to 300 hours.
It is about 150 hours.

The hafnium compound as described above is used in an amount of usually 10 ^-8 to 10 ^-2 gram atom / l, preferably 10 ^-7 to 10 ^-3 gram atom / l as the concentration of the hafnium atom in the polymerization reaction system. It is desirable that

The aluminoxane as described above is converted to 10 ^-4 to 10 ^-1 gram atom / l, preferably 5 × 10 ^{-4 to} 5 × 10 ^-2 gram atom / l in terms of aluminum atom in the reaction system. Preferably, it is used in an amount.

The polymerization temperature is desirably in the range of -50 to 150C, preferably 0 to 120C.

The polymerization of the olefin as described above is usually performed in a gas phase or a liquid phase. In liquid phase polymerization, an inert hydrocarbon may be used as a solvent, or an olefin itself may be used as a solvent.

As the hydrocarbon solvent, specifically, butane, isobutane, pentane, hexane, heptane, octane, decane, dodecane, hexadecane, aliphatic hydrocarbons such as octadecane, cyclopentane, methylcyclopentane, cyclohexane, cyclooctane and the like Alicyclic hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene, and petroleum fractions such as gasoline, kerosene, and light oil are used.

The polymerization pressure is usually from atmospheric pressure 100 kg / cm ^2, preferably under conditions of from normal pressure 50 kg / cm ^2, the polymerization is a batch,
It can be carried out by any of a semi-continuous method and a continuous method. The molecular weight of the polymer can be adjusted by hydrogen and / or polymerization temperature.

Effect of the Invention The novel ethylene copolymer according to the present invention has w / n
Is small, the molecular weight distribution is narrow, and MFR ₁₀ / MFR ₂ is large, so that the fluidity is excellent. Therefore, this ethylene-based copolymer has excellent workability and also has excellent blocking resistance and the like.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1 (Preparation of methylaluminoxane) Prepared according to Polymer Commun., 29 , 180 (1988).

(Synthesis of ethylene bis (indenyl) hafnium dichloride) A nitrogen-substituted 200 ml glass flask was charged with 5.4 g of bis (indenyl) ethane (synthesized based on Bull. Soc. Chim., 2954 (1967)) and 50 ml of THF. -30 with stirring
Cooled to ~ -40 ° C. N-BuLi (1.6M solution) 3
1.5 ml was added dropwise, followed by stirring at −30 ° C. for 1 hour.
Bis (indenyl) ethane was anionized by naturally warming to room temperature. In another 200 ml glass flask purged with nitrogen, 60 ml of THF was charged and cooled to -60 ° C or lower, and HfCl ₄ (0.78% by weight of zirconium atom as contaminant)
6.7 g) were gradually added. Then 60 ° C
And stirred for 1 hour. The anionized ligand was added dropwise thereto, and the mixture was stirred at 60 ° C. for 2 hours, and then filtered with a glass filter. The filtrate was concentrated to about the first 1/5 volume at room temperature. By this operation, a solid precipitates. The precipitated solid was filtered through a glass filter, washed with hexane / ethyl ether, and dried under reduced pressure to obtain ethylenebis (indenyl) hafnium dichloride.

The hafnium compound contained 0.40% by weight of zirconium atoms.

(Polymerization) Toluene is placed in a 2 l glass flask with
950 ml and 1-octene 50 ml were added, and ethylene gas was further passed at 160 l / hr. After the temperature of the system was raised to 55 ° C., 1.88 mmol of methylaluminoxane in terms of aluminum atoms and 7.5 × 10 ⁻³ mmol of ethylenebis (indenyl) hafnium dichloride were added to initiate polymerization. At 60 ° C under normal pressure while continuously supplying ethylene gas
Polymerization was performed for 10 minutes. The polymerization was stopped by adding a small amount of methanol, and the obtained polymerization solution was poured into a large amount of methanol to precipitate the polymer.
The polymer thus obtained was dried under reduced pressure at 130 ° C. for 12 hours to have a density of 0.866 g / cm ³ , an ethylene content of 81.3 mol%, an [η] of 1.71 dl / g, and a w / n of 2.59
And MFR ₂ is 2.12 g / 10 minutes, and the ratio of MFR ₁₀ / MFR ₂ is 1
23.2 g of the polymer 3.1 was obtained.

Example 2 Toluene (1) was charged into a 2-liter glass flask sufficiently purged with nitrogen, and a mixed gas of ethylene and propylene (140 l / h and 40 l / h, respectively) was passed. After the temperature of the system was raised to 75 ° C., 1.88 mmol of methylaluminoxane in terms of aluminum atoms and 7.5 × 10 ⁻³ mmol of ethylenebis (indenyl) hafnium dichloride were added to initiate polymerization. Polymerization was carried out at 80 ° C. for 10 minutes under normal pressure while continuously supplying the mixed gas. The subsequent operation was performed in the same manner as in Example 1, and the density was 0.887 g / cm ^3.
And the ethylene content is 84.0 mol%, and [η] is 1.
50 dl / g, w / n is 2.50, MFR ₂ is 0.80 g / 10
17.5 g of a polymer having an MFR ₁₀ / MFR ₂ ratio of 12.7
was gotten.

Comparative Example 1 The density was 0.87 g / cm ³ and the MFR ₂ was 2.9 g / cm ³ , w
copolymer of ethylene and propylene (V / n is 2.16)
The MFR ₁₀ / MFR ₂ ratio of the catalyst composed of OCl ₃ and aluminum ethyl sesquichloride was 5.90.

Example 3 (Preparation of hafnium catalyst) 40 g of dimethylsilylated silica gel (Art.7719 manufactured by MERCK) degassed at room temperature for 4 hours was suspended in toluene and packed in a glass column having an inner diameter of 35 mm under a nitrogen atmosphere. did. Next, 200 ml of a toluene solution of ethylene bis (indenyl) hafnium dichloride (Hf = 2.07 mmol / l) prepared in Example 1 was gradually poured into the column. Hafnium solution eluted by the above operation (Hf = 0.17 mmol / l)
Was used as a catalyst component.

(Polymerization) Polymerization was carried out in the same manner as in Example 1 except that 6.6 × 10 ⁻³ milligram atoms were used as hafnium atoms and polymerization was performed at 70 ° C. for 35 minutes. The density was 0.855 g / cm ³ , and the ethylene content was 76.2. Mol%, [η] is 1.89 dl / g,
w / n is 2.48, MFR ₂ is 1.49 g / 10 min, MFR ₁₀
42.4 g of a colorless and transparent polymer having a / MFR ₂ ratio of 10.1 was obtained.

Example 4 Polymerization was carried out in the same manner as in Example 2 except that the hafnium catalyst component prepared in Example 3 was used as hafnium atoms at 6.6 × 10 ⁻³ milligram atoms, and the density was 0.883 g / cm ^3.
And the ethylene content is 83.5 mol%, and [η] is 1.
61 dl / g, w / n is 2.54, MFR ₂ is 0.73 g / 10
And 17.0 g of a colorless and transparent polymer having an MFR ₁₀ / MFR ₂ ratio of 12.2 was obtained.

Example 5 When the polymerization was carried out in the same manner as in Example 1 except that the polymerization temperature was 40 ° C. and the polymerization time was 15 minutes, the density was 0.868 g / cm ³ and the ethylene content was 82.0 mol%. , [Η] is 1.79 dl / g, w / n is 2.81,
20.5 g of polymer having an MFR ₂ of 0.90 g / 10 min and an MFR ₁₀ / MFR ₂ ratio of 32.0 were obtained.

Example 6 (Preparation of methylaluminoxane) Toluene was distilled off from a toluene solution of methylaluminoxane (manufactured by Witco) using an evaporator and dried. This was redissolved in toluene and used for polymerization.

(Polymerization) To a glass flask sufficiently purged with nitrogen, 500 ml of toluene and 5 ml of 1-octene were added, and the temperature of the system was raised to 90 ° C. Thereafter, ethylene gas was flowed at a rate of 100 l / hr. Subsequently, 2,5 mmol of methylaluminoxane in terms of aluminum atom and ethylenebis (indenyl) hafnium dichloride synthesized in Example 1 were converted to 3.3 × 10
^-3 mmol was added to initiate polymerization. Polymerization was performed at 90 ° C. for 10 minutes under normal pressure while continuously supplying ethylene gas.

The polymerization was stopped by adding a small amount of methanol, and the obtained polymerization solution was poured into a large amount of methanol to precipitate a polymer.

By drying the precipitated polymer at 80 ° C. under reduced pressure for 12 hours, the density is 0.901 g / cm ³ and the ethylene content is 9
4.0 mol%, [η] is 1.45 dl / g, w / n
Is 2.35, MFR ₂ is 1.80 g / 10 min, and MFR ₁₀ / MFR ₂
6.1 g of a polymer having a ratio of 9.2 was obtained.

Example 7 The same operation as in Example 6 was carried out except that the amount of 1-octene was changed to 3 ml, the density was 0.915 g / cm ³ , the ethylene content was 96.2 mol%, and [η] Is 1.67dl
/ g, w / n was 2.53, MFR ₂ was 0.70 g / 10 minutes, and 6.2 g of a polymer having a ratio of MFR ₁₀ / MFR ₂ of 11.8 was obtained.

Example 8 The same operation as in Example 6 was carried out except that the amount of 1-octene was changed to 4 ml, the density was 0.907 g / cm ³ , the ethylene content was 95.1 mol%, and [η] Is 1.49dl
/ g, w / n was 2.22, MFR ₂ was 1.48 g / 10 min, and 5.6 g of a polymer having a ratio of MFR ₁₀ / MFR ₂ of 8.7 was obtained.

Example 9 The same operation as in Example 6 was carried out except that the amount of ethylenebis (indenyl) hafnium dichloride was changed to 3.75 × 10 ⁻³ mmol, and polymerization was carried out at 80 ° C. for 20 minutes, and the density was 0.902 g. / cm ³ , ethylene content 94.6 mol%, [η] 0.97 dl / g, w / n 2.82, MFR ₂ 0.025 g / 10 min, MFR ₁₀ / MFR ₂ The ratio is 2
14.0 g of 9.6 polymer was obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a process for producing an ethylene copolymer according to the present invention.

Claims (2)

(57) [Claims] (1) A structural unit (a) derived from ethylene is 60
(E) an ethylene copolymer containing the structural unit (b) derived from an α-olefin having 3 to 20 carbon atoms in an amount of 4 to 40 mol% in an amount of 4 to 40 mol%; Density of ethylene copolymer is 0.85 ~ 0.92g / cm
Is ^3, the (B) an intrinsic viscosity, measured in a 135 ° C. decalin [eta]
(C) the ratio (w / n) of the weight average molecular weight (w) to the number average molecular weight (n) measured by GPC is in the range of 1.2 to 4, and (D) An ethylene copolymer, wherein the ratio of MFR ₁₀ at a load of 10 kg at 190 ° C. to MFR ₂ at a load of 2.16 kg (MFR ₁₀ / MFR ₂ ) is in the range of 8 to 50. 2. A hafnium compound or a hafnium compound having as a ligand a polydentate compound in which at least two groups selected from an indenyl group or a substituent thereof are bonded via a lower alkylene group. In the presence of a catalyst formed from a hafnium catalyst component obtained by treating the compound with an alkylsilylated silica gel, and (B) a catalyst formed from an organoaluminum oxy compound.
An α-olefin having 20 and a structural unit (a) derived from ethylene in an amount of 60 to 96 mol% and an α-olefin having 3 to 20 carbon atoms
The intrinsic viscosity, measured in decalin at 135 ° C., containing 4 to 40 mol% of structural units (b) derived from olefins and copolymerized to a density of 0.85 to 0.92 g / cm ³ [Η] is 0.1 to 10
dl / g, the ratio (w / n) of the weight average molecular weight (w) to the number average molecular weight (n) measured by GPC is in the range of 1.2 to 4, and MFR at 190 ° C under a 10 kg load. _{A process} for producing an ethylene copolymer, wherein the ratio of MFR ₂ to MFR ₂ at a load of 2.16 kg (MFR ₁₀ / MFR ₂ ) is in the range of 8 to 50; .