JPH08302083A - Ethylene-based polymer composition - Google Patents

Abstract

PURPOSE: To obtain an ethylene-based polymer composition excellent in moldability, impact resistance and ESCR(environmental stress cracking resis tance) and also excellent in balance between these properties. CONSTITUTION: This ethylene-based polymer composition comprises (1) a specific high-density, low-molecular weight ethylene-based polymer and (2) a specific low-density, high-molecular weight ethylene-based polymer and has the following characteristics: density: 0.940-0.970g/cm<3> ; MFR: 0.005-1.0g/10min; Mw/Mn: 5-40; Mz/Mw: 3-20; and g*-value as an indicator of long chain branch proportion: 0.90-1.00. This composition is obtained by multistage polymerization process.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD OF THE INVENTION The present invention relates to an ethylene-based polymer composition, and more specifically, it has moldability, impact strength and ESCR (combustion strength) as compared with conventionally known ethylene-based polymers or ethylene-based polymer compositions. The present invention relates to an ethylene-based polymer composition which is excellent in environmental stress cracking property) and has a good balance thereof.

[0002]

TECHNICAL BACKGROUND OF THE INVENTION Ethylene-based polymers (ethylene homopolymers and ethylene copolymers) are blow molded, vacuum / pressure molded, calender molded, inflation molded,
It is molded by various molding methods such as extrusion molding, foam molding, stretched film molding, and injection molding, and is used for various purposes.

Such ethylene-based polymers have different required properties depending on the molding method and the application. For example, it is necessary to select an ethylene polymer having a large melt tension in order to prevent the bubbles from shaking and breaking when the blown film is molded at a high speed. Also, in order to improve the pinch-off shape when manufacturing chemical cans, drums, bottles, etc. by blow molding, or to narrow the wall thickness distribution of blow molded products, select an ethylene polymer with a large swell ratio. There is a need to. Further, required properties of blow-molded products include excellent impact resistance and excellent ESCR. Recently, it has been required to improve rigidity to reduce the wall thickness of molded products and improve economic efficiency. is there.

By the way, the ethylene-based polymer produced by the Ziegler-Natta type catalyst represented by the MgCl ₂ -supporting Ti-based catalyst has almost no long chain branching and is excellent in rigidity and impact resistance. , Inferior in moldability to the ethylene polymer produced by the Cr-based Phillips type catalyst. On the other hand, the ethylene polymer produced by the high pressure method and the ethylene polymer produced by the Cr Phillips type catalyst have a melt tension and a swell ratio higher than those of the ethylene polymer produced by the Ziegler-Natta type catalyst. High and excellent in moldability, but poor in rigidity and impact strength due to the presence of long chain branches.

Under these circumstances, various studies have been made to obtain an ethylene polymer excellent in moldability and impact strength by using a Ziegler-Natta type catalyst. For example, JP-A-55-12735 discloses an ethylene polymer (composition) obtained by blending an ethylene polymer produced by a Ziegler-Natta type catalyst with an ethylene polymer produced by a high pressure method. Is listed. Also,
Japanese Patent Application Laid-Open No. 60-36546 discloses an ethylene-based polymer prepared by blending an ethylene-based polymer produced by a Ziegler-Natta type catalyst with an ethylene-based polymer produced by a Cr-type Phillips type catalyst (composition. The thing) is described. However, although these ethylene-based polymers (compositions) have improved moldability, the proportion of long-chain branches in the polymer increases, so that the ethylene-based polymers produced by the Ziegler-Natta type catalyst originally have It has excellent rigidity and reduced impact strength.

Further, JP-A-59-89341 discloses an ethylene polymer produced by modifying an ethylene polymer produced by a Ziegler-Natta type catalyst in the presence of a radical generator. Japanese Patent Laid-Open No. 59-16434
No. 7, etc., describes an ethylene polymer obtained by modifying an ethylene polymer produced by a Ziegler-Natta type catalyst in the presence of maleic acid. However, in this case as well, although the moldability is improved, the ratio of long-chain branches in the polymer is increased, and thus the rigidity and the impact strength are lowered.

Therefore, if an ethylene-based polymer that is superior in moldability, impact strength and ESCR and has a good balance of these properties to the conventional ethylene-based polymer appears, its industrial value will be extremely great.

As a result of studies in view of such prior art, the present inventors have found that the melt flow rate and the melt tension have a specific relationship, that is, the value of the molecular weight distribution Mw / Mn, the value of the molecular weight distribution Mz / Mw, An ethylene (co) polymer having a g ^* value, which is an index showing the proportion of long-chain branching, and a swell ratio in a specific range, has excellent moldability, mechanical strength, and appearance It was found that the body can be obtained. And it has been found that such an ethylene polymer can be produced by using an ethylene polymerization catalyst containing a specific solid titanium catalyst component.

As a result of further research, it is composed of a specific high density / low molecular weight ethylene polymer and a specific low density / high molecular weight ethylene polymer, and at least one of the ethylene polymers. However, there is a specific relationship between the melt flow rate and the melt tension, and the molecular weight distribution M
The composition in which the value of w / Mn, the value of the molecular weight distribution Mz / Mw, the value of g ^* which is an index showing the ratio of long chain branching, and the swell ratio are in the respective specific ranges has moldability, impact strength and The inventors have completed the present invention by finding that they are excellent in ESCR and particularly excellent in their balance.

[0010]

OBJECTS OF THE INVENTION The present invention is directed to formability, impact strength and E
It is an object of the present invention to provide an ethylene-based polymer composition having excellent SCR and an excellent balance thereof.

[0011]

The ethylene polymer composition according to the present invention is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and has a density of 0.950. ~ 0.980 g / cm ³ range,
Ethylene polymer (1) having a melt flow rate in the range of 0.1 to 300 g / 10 minutes at 190 ° C. under a load of 2.16 kg; 20 to 90% by weight, and an ethylene homopolymer or ethylene and the number of carbon atoms. Is a copolymer with 3 to 20 α-olefin and has a density of 0.910 to 0.9.
It is in the range of 65 g / cm ³ , 190 ° C, 2.16 kg
The melt flow rate under load is 0.0001-0.
Ethylene polymer (2) in the range of 1 g / 10 minutes; 80
10 to 10% by weight of the ethylene polymer (1)
And at least one of the ethylene polymer (2) has an Mw / Mn value in the range of 2 to 9, an Mz / Mw value in the range of 2 to 5, and is an index indicating the proportion of long-chain branching. The value of g ^* is 0.90
The melt tension (MT) and melt flow rate (M
FR) satisfies the relationship represented by the following formula, and has a log (MT) ≧ −0.4 log (MFR) +0.75 swell ratio of more than 1.35, which is (i) The ratio (d ₁ / d ₂ ) of the density (d ₁ ) of the ethylene polymer ( ₁ ) and the density (d ₂ ) of the ethylene polymer (2) exceeds 1, and (ii) the density is 0. In the range of 0.940 to 0.970 g / cm ³ ,
(Iii) the melt flow rate at 190 ° C. under a load of 2.16 kg is in the range of 0.005 to 1.0 g / 10 minutes, (iv) the value of Mw / Mn is in the range of 5 to 40,
(V) The value of Mz / Mw is in the range of 3 to 20, and (vi)
The value of g ^* , which is an index showing the ratio of long-chain branching, is 0.90 to
It is characterized by being in the 1.00 range.

In the present invention, the ethylene polymer (1)
And the ethylene-based polymer (2), which is (I) (A) (a) (a-1) a halogen-containing magnesium compound, an alcohol having 6 or more carbon atoms, and a magnesium solution formed from a hydrocarbon solvent. , (A-2) magnesium, halogen, aluminum obtained by contacting with an organoaluminum compound, and having 6 carbon atoms
A solid magnesium-aluminum composite containing the above alkoxy group and / or an alcohol having 6 or more carbon atoms, and (b) a tetravalent titanium compound are in contact with each other. The valence of titanium contained therein is substantially tetravalent, [alkoxy group having 6 or more carbon atoms and / or alcohol having 6 or more carbon atoms] / Ti
By contacting a solid titanium composite having a (molar ratio) in the range of 0.26 to 6.0 with (B) an organometallic compound containing a metal selected from Group I to Group III of the periodic table. A solid titanium catalyst component obtained by contacting the obtained solid titanium / organometallic compound composite with oxygen, and (II) an organometallic compound containing a metal selected from Groups I to III of the periodic table. It is preferably produced by an olefin polymerization catalyst containing

The ethylene-based polymer composition according to the present invention uses a plurality of polymerization vessels, and in any one or more of the plurality of polymerization vessels, the ethylene-based polymer (1) is used. Ethylene polymerized in another polymerization vessel (2)
It is more preferable that the ethylene polymer (1) is polymerized in the first stage and the ethylene polymer (2) is polymerized in the latter stage by using a two-stage polymerization method. It is preferably obtained by polymerization or by polymerizing the ethylene polymer (2) in the first stage and polymerizing the ethylene polymer (1) in the second stage.

Further, in the present invention, the ethylene polymer produced in at least the first stage among the ethylene polymer (1) and the ethylene polymer (2) has a Mw / Mn value of 2-9. And the value of Mz / Mw is in the range of 2 to 5, and the value of g ^* which is an index showing the ratio of long chain branching is 0.90.
The melt tension (MT) and melt flow rate (M
FR) and the relationship represented by the following formula, and log (MT) ≧ −0.4 log (MFR) +0.75 It is preferable that the swell ratio exceeds 1.35.

Such an ethylene-based polymer composition is excellent in moldability, impact resistance and ESCR, and is excellent in the balance thereof.

[0016]

DETAILED DESCRIPTION OF THE INVENTION The ethylene polymer composition according to the present invention will be specifically described below. In the present specification, the term “polymerization” may be used to mean not only homopolymerization but also copolymerization, and the term “polymer” means not only homopolymer but also copolymerization. It may be used in the sense of including coalescence.

The ethylene polymer composition according to the present invention is
It is formed from an ethylene polymer (1) and an ethylene polymer (2) as described below. First, the ethylene polymer (1) and the ethylene polymer (2) forming the ethylene polymer composition according to the present invention will be described.

Ethylene-based Polymer (1) The ethylene-based polymer (1) forming the ethylene-based polymer composition according to the present invention is an ethylene homopolymer or ethylene-α- having 3 to 20 carbon atoms. It is a random copolymer with an olefin.

Here, as the α-olefin having 3 to 20 carbon atoms, propylene, 1-butene, 1-pentene,
1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene,
Examples include 1-octadecene and 1-eicosene.

In the ethylene polymer (1), the constitutional unit derived from ethylene is present in an amount of 55 to 100% by weight, preferably 65 to 100% by weight, more preferably 70 to 100% by weight, and a carbon atom. It is desirable that the structural unit derived from the α-olefin having a number of 3 to 20 be present in an amount of 0 to 45% by weight, preferably 0 to 35% by weight, more preferably 0 to 30% by weight.

The ethylene polymer (1) is an aromatic vinyl compound such as styrene or allylbenzene, an alicyclic vinyl compound such as vinylcyclohexane, cyclopentene,
Cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene Such as cyclic olefins, 6-methyl-1,6-octadiene, 7-methyl-1,6-octadiene, 6-ethyl-1,6-octadiene, 6-
Propyl-1,6-octadiene, 6-butyl-1,6-octadiene, 6-methyl-1,6-nonadiene, 7-methyl-1,6-nonadiene, 6-ethyl-1,6-nonadiene, 7- Conjugated dienes such as ethyl-1,6-nonadiene, 6-methyl-1,6-decadiene, 7-methyl-1,6-decadiene, 6-methyl-1,6-undecadiene, isoprene and butadiene The constitutional unit derived from a compound having a polyunsaturated bond such as a non-conjugated diene may be contained in an amount of 10% by weight or less, preferably 5% by weight or less.

The composition of the polymer is usually ¹³ C-NMR spectrum of a sample in which about 200 mg of the copolymer is uniformly dissolved in 1 ml of hexachlorobutadiene in a sample tube of 10 mmφ. .05 MH
z, spectrum width 1500 Hz, pulse repetition time 4.
It is determined by measuring under the measurement conditions of 2 sec. And pulse width 6 μsec.

Such ethylene polymer (1) has a density of 0.950 to 0.980 g / cm ³ , preferably 0.955 to 0.980 g / cm ³ , and more preferably 0.960 to 0. It is desirable that the melt flow rate (MFR) is in the range of 980 g / cm ³ , and the melt flow rate (MFR) is 0.1 to 10.
300 g / 10 minutes, preferably 0.5-250 g / 10
Min, more preferably 1.0 to 200 g / 10 min.

The density is 2.16k at 190 ° C.
The strand obtained at the time of measuring the melt flow rate under g load is heat-treated at 120 ° C. for 1 hour, gradually cooled to room temperature over 1 hour, and then measured with a density gradient tube.

MFR is 1 according to ASTM D1238-65T
It is measured under the conditions of 90 ° C. and 2.16 kg load. Furthermore, it is desirable that the ethylene polymer (1) has the following characteristics.

The value of the molecular weight distribution Mw / Mn represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 2-9, preferably 3-8, more preferably 4-7.
Is in the range.

The value of the molecular weight distribution Mz / Mw represented by the ratio of the Z average molecular weight (Mz) and the weight average molecular weight (Mw) is 2-5, preferably 2.5-4.5, more preferably 3
It is in the range of ~ 4.

Mw / Mn and Mz / Mw are gel per
Using Mation Chromatography (GPC),
Measure as described. [Device] ALC / GPC 150C type manufactured by Millipore [Measurement conditions] Column: GMH-HT6 (7.5 mm ID × 60 cm)
Tosoh mobile phase: o-Dichlorobenzene (ODCB) Column temperature: 138 ° C Flow rate: 1.0 ml / min Sample concentration: 30 mg / 20 ml Dissolution temperature: 140 ° C Inflow rate: 500 ml Detector: Differential refractometer [Mw / Mn and Calculation of Mz / Mw] GPC elution curve
Elution time R for the i-th segment of_ti, Elution amount H_i, Minutes
Child M _iHave the following relationship.

[0029]

[Equation 1]

(However, P (1), P (2), P (3)
And P (4) are standard samples polystyrene (Mw / Mn
= 1.1) is calculated from the calibration curve showing the elution amount versus the molecular weight obtained by GPC measurement under the above conditions. ) From the obtained values of M _i and H _i , Mn, Mw, and Mz were calculated by the following equations to obtain Mw / Mn and Mz / Mw.

Mn = ΣH _i / Σ (H _i / M _i ) Mw = ΣH _i M _i / ΣH _i Mz = ΣH _i M _i ² / ΣH _i M _i g ^* which is an index showing the ratio of long chain branching Value 0.90
To 1.00, preferably 0.92 to 1.00, and more preferably 0.95 to 1.00.

Since the ethylene polymer having a value of g ^{* in} the above range has a small proportion of long chain branching in the polymer, a molded product obtained from the composition containing the ethylene polymer has a high rigidity. And excellent in impact strength.

The value of g ^* is obtained by using GPC as follows. That is, the values of M _i and H _i are obtained under the same measurement conditions as above,

[0034]

[Equation 2]

It is calculated by the method described in the literature (Pollock, D., a
nd Kratz, FF, GPC Sixth international Seminar (196
8)), the value in decalin solvent ([η] _GPC )
Corrected to. In addition, the intrinsic viscosity ([η] _obs ) in a decalin solvent at 135 ° C. was measured for each sample.

From the values thus obtained, g ^* was calculated using the following formula. g ^* = [η] _obs / [η] _GPC Melt tension (MT) and melt flow rate (M
FR) is the expression log (MT) ≧ −0.4 log (MFR) +0.75, preferably the expression log (MT) ≧ −0.4 log (MFR) +0.78, more preferably the expression log (MT ) ≧ −0.4 log (MFR) +0.80 is satisfied.

Swell ratio (SR) exceeds 1.35
It Swell ratio is above 1.35 and below 2.50
It is preferred that The swell ratio is as described below
MFR of ethylene-based polymer composition as measured by the method
Is 0.005 g / 10 minutes or more and less than 0.1 g / 10 minutes
In some cases, shear rate 200 sec^-1Measured with
The MFR of the ren-based polymer composition is 0.1 g / 10 minutes or more,
If it is less than 1.0g / 10 minutes, the shear rate is 100
0 sec ^-1Measured at.

The ethylene polymer (1) having the above-mentioned characteristics has a density of ethylene of 0.950 to 0.980 g / c in the presence of, for example, a Ziegler-Natta type catalyst.
m ³ become do homopolymerized, or ethylene and carbon atoms density and 3-20 of α- olefins 0.
It can be produced by copolymerizing so as to give 950 to 0.980 g / cm ³ , but in the present invention, ethylene is added in the presence of an olefin polymerization catalyst containing a solid titanium catalyst component as described below. Is preferably homopolymerized, or ethylene and an α-olefin having 3 to 20 carbon atoms are preferably copolymerized.

Ethylene-based Polymer (2) The ethylene-based polymer (2) forming the ethylene-based polymer composition according to the present invention is an ethylene homopolymer or ethylene-α- having 3 to 20 carbon atoms. It is a random copolymer with an olefin.

Here, as the α-olefin having 3 to 20 carbon atoms, the same ones as mentioned above can be mentioned. In the ethylene polymer (2), the constitutional unit derived from ethylene is present in an amount of 55 to 100% by weight, preferably 65 to 100% by weight, more preferably 70 to 100% by weight and having 3 carbon atoms. Constituent units derived from .alpha.-olefins of .about.20 are desirably present in an amount of 0 to 45% by weight, preferably 0 to 35% by weight, more preferably 0 to 30% by weight.

The ethylene-based polymer (2) is a compound having a polyunsaturated bond such as a conjugated diene or a non-conjugated diene such as an aromatic vinyl compound, an alicyclic vinyl compound, a cyclic olefin, or a diene as described above. The constitutional unit derived from the above may be contained in an amount of 10% by weight or less, preferably 5% by weight or less.

Such an ethylene polymer (2) has a density of 0.910 to 0.965 g / cm ³ , preferably 0.915 to 0.960 g / cm ³ , and more preferably 0.920 to 0. 960 g / cm ^3, particularly preferably it is desirable in the range of 0.920~0.959g / cm ^3, melt flow rate, 0.0001 to 0.
1 g / 10 minutes, preferably 0.0005-0.05 g /
It is preferably in the range of 10 minutes.

Furthermore, it is desirable that the ethylene polymer (2) has the following characteristics. The value of the molecular weight distribution Mw / Mn represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is in the range of 2 to 9, preferably 3 to 8, and more preferably 4 to 7.

The value of the molecular weight distribution Mz / Mw represented by the ratio of the Z average molecular weight (Mz) and the weight average molecular weight (Mw) is 2 to 5, preferably 2.5 to 4.5, more preferably 3
It is in the range of ~ 4.

The value of g ^* which is an index showing the ratio of long chain branching is 0.90 to 1.00, preferably 0.92 to 1.0.
0, more preferably 0.95 to 1.00.
An ethylene-based polymer having a g ^* value in the above range has a small proportion of long-chain branching in the polymer, and thus the obtained molded product is excellent in rigidity and impact resistance.

The melt tension (MT) and the melt flow rate (MFR) have the formula log (MT) ≧ −0.4 log (MFR) +0.75, preferably the formula log (MT) ≧ −0.4 log ( MFR) +0.78 More preferably, the relationship represented by the formula log (MT) ≧ −0.4 log (MFR) +0.80 is satisfied.

The swell ratio (SR) exceeds 1.35. The swell ratio is preferably more than 1.35 and not more than 2.50. The ethylene polymer (2) having the above characteristics is
For example, it is produced by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms in the presence of a Ziegler-Natta type catalyst so as to have a density of 0.910 to 0.965 g / cm ^3. However, in the present invention, it is particularly preferable to copolymerize ethylene with an α-olefin having 3 to 20 carbon atoms in the presence of an olefin polymerization catalyst containing a solid titanium catalyst component as described below. .

Olefin Polymerization Catalyst Next, the olefin polymerization catalyst preferably used for the production of the ethylene polymer (1) and the ethylene polymer (2) will be described.

Such an olefin polymerization catalyst is (I) (A) (a) (a-1) a halogen-containing magnesium compound, an alcohol having 6 or more carbon atoms, and a magnesium solution formed from a hydrocarbon solvent. And (a-2) an organoaluminum compound are contacted with each other to obtain magnesium, halogen, aluminum, and carbon atoms of 6
A solid magnesium-aluminum composite containing the above alkoxy group and / or an alcohol having 6 or more carbon atoms, and (b) a tetravalent titanium compound are in contact with each other. The valence of titanium contained therein is substantially tetravalent, [alkoxy group having 6 or more carbon atoms and / or alcohol having 6 or more carbon atoms] / Ti
By contacting a solid titanium composite having a (molar ratio) in the range of 0.26 to 6.0 with (B) an organometallic compound containing a metal selected from Group I to Group III of the periodic table. A solid titanium catalyst component obtained by contacting the obtained solid titanium / organometallic compound composite with oxygen, and (II) an organometallic compound containing a metal selected from Groups I to III of the periodic table. Is included.

The solid magnesium-aluminum composite (a), the tetravalent titanium compound (b), the solid titanium composite (A), the organometallic compound (B) and the organometallic compound (II) will be sequentially described below. To do.

First, the solid magnesium-aluminum composite (a) containing magnesium, halogen, aluminum, and an alkoxy group having 6 or more carbon atoms and / or an alcohol having 6 or more carbon atoms will be described.

This solid magnesium-aluminum composite (a) is (a-1) a magnesium solution formed from a halogen-containing magnesium compound, an alcohol having 6 or more carbon atoms, and a hydrocarbon solvent, and (a- 2) Obtained by contacting with an organoaluminum compound.

In the solid magnesium-aluminum composite (a), the atomic ratio of aluminum (Al) to magnesium (Mg) (Al / Mg) is usually 0.05.
To 1, preferably 0.08 to 0.7, more preferably 0.12 to 0.6, the amount of an alkoxy group having 6 or more carbon atoms and / or an alcohol having 6 or more carbon atoms. Is usually 0.5 per 1 part by weight of magnesium.
To 15 parts by weight, preferably 2 to 13 parts by weight, more preferably 5 to 10 parts by weight, halogen (Hal)
And the atomic ratio of magnesium (Mg) (Hal / Mg)
Is usually in the range of 1 to 3, preferably 1.5 to 2.5.

The solid magnesium-aluminum composite (a) has a particle size of preferably 1 to 200 μm, more preferably 2 to 100 μm, and a geometric standard deviation of particle size distribution of 1.0 to 2.0. Preferably 1.0-1.
It is preferably in the range of 8 and granular.

Specific examples of the halogen-containing magnesium compound used when preparing the magnesium solution (a-1) include the following compounds. Magnesium halide such as magnesium chloride, magnesium bromide, magnesium iodide, magnesium fluoride, methoxy magnesium chloride, ethoxy magnesium chloride, isopropoxy magnesium chloride, butoxy magnesium chloride,
Alkoxy magnesium halides such as octoxy magnesium chloride, phenoxy magnesium chloride, allyloxy magnesium halides such as methylphenoxy magnesium chloride, diethoxy magnesium, diisopropoxy magnesium, dibutoxy magnesium, dioctoxy magnesium and other alkoxy magnesium, diphenoxy magnesium, Allyloxy magnesium such as dimethylphenoxy magnesium, magnesium laurate, magnesium carboxylates such as magnesium stearate, and the like.

The halogen-containing magnesium compound may be a complex compound of these compounds with another metal, a double compound, or a mixture with another metal compound. Among these, magnesium halide and alkoxy magnesium halide are preferable, magnesium chloride and alkoxy magnesium chloride are more preferable, and magnesium chloride is particularly preferable.

These halogen-containing magnesium compounds may be used alone or in combination of two or more. Specific examples of the alcohol having 6 or more carbon atoms used when preparing the magnesium solution (a-1) include:
The following compounds may be mentioned.

2-methylpentanol, 2-ethylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, 2-ethylhexanol, decanol, dodecanol, tetradecyl alcohol, undecenol, oleyl alcohol, stearyl alcohol, etc. Aliphatic alcohols, cycloaliphatic alcohols such as cyclohexanol and methylcyclohexanol, benzyl alcohol, methylbenzyl alcohol, isopropylbenzyl alcohol, α-methylbenzyl alcohol, aromatic alcohols such as α, α-dimethylbenzyl alcohol, n-butyl cellosolve , Aliphatic alcohols containing alkoxy groups such as 1-butoxy-2-propanol.

Of these, alcohols having 7 or more carbon atoms are preferable, and 2-ethylhexanol is particularly preferable. These alcohols may be used alone or in combination of two or more.

Specific examples of the hydrocarbon solvent used when preparing the magnesium solution (a-1) include the following compounds. Propane, butane, n-pentane, isopentane, n-hexane, isohexane, n-
Heptane, n-octane, isooctane, n-decane, n-dodecane, aliphatic hydrocarbons such as kerosene, cyclopentane,
Alicyclic hydrocarbons such as methylcyclopentane, cyclohexane, methylcyclohexane, benzene, toluene,
Aromatic hydrocarbons such as xylene, methylene dichloride,
Halogenated hydrocarbons such as ethyl chloride, ethylene dichloride and chlorobenzene.

Of these, aliphatic hydrocarbons, particularly aliphatic hydrocarbons having 3 to 10 carbon atoms, are preferably used. These hydrocarbon solvents may be used alone or in combination of two or more.

The halogen-containing magnesium compound,
When the alcohol having 6 or more carbon atoms is brought into contact with the hydrocarbon solvent, the halogen-containing magnesium compound is dissolved in the hydrocarbon solvent to give a magnesium solution (a-1).
Is obtained.

The contact between the halogen-containing magnesium compound as described above, the alcohol having 6 or more carbon atoms, and the hydrocarbon solvent varies depending on the kind of the compound and alcohol used, but is usually room temperature or higher, preferably 65 ° C or higher, more preferably about 80 to about 300 ° C,
It is particularly preferably carried out at a temperature of about 100 to about 200 ° C. for about 15 minutes to 5 hours, more preferably about 30 minutes to 3 hours.

At this time, the alcohol is usually about 1 mol or more, preferably about 1.5 to about 20 mol, and more preferably 1 mol per 1 mol of the halogen-containing magnesium compound, though it varies depending on the type of magnesium compound and solvent used. Is used in an amount of about 2.0 to about 12 moles.
The hydrocarbon solvent is preferably used in an amount such that the magnesium concentration in the obtained magnesium solution will be 0.005 to 2 mol / liter.

By bringing the magnesium solution (a-1) into contact with the organoaluminum compound (a-2) described later, a solid magnesium-aluminum composite (a) can be obtained.

As the organoaluminum compound (a-2) used for preparing the solid magnesium-aluminum composite (a), specifically, for example, an aluminum compound represented by the following formula (i) is preferably used.

R ¹ _n AlX _3-n (i) In the formula, R ¹ represents a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom or a hydrogen atom, and n is 1 to 1
It is 3.

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group and an aryl group. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group and an isobutyl group. Group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.

Such an organoaluminum compound (a-2)
Specifically, the following compounds may be mentioned.
Trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri2-ethylhexylaluminum, alkenylaluminum such as isoprenylaluminum,
Dialkyl aluminum halides such as dimethyl aluminum chloride, diethyl aluminum chloride, diisopropyl aluminum chloride, diisobutyl aluminum chloride, and dimethyl aluminum bromide, methyl aluminum sesquichloride, ethyl aluminum sesquichloride, isopropyl aluminum sesquichloride, butyl aluminum sesquichloride, ethyl aluminum sesquibromide, etc. Alkyl aluminum sesquihalide, methyl aluminum dichloride, ethyl aluminum dichloride, isopropyl aluminum dichloride, ethyl aluminum dibromide, etc. alkyl aluminum dihalide, diethyl aluminum hydride, diisobutyl aluminum hydride, etc. Such as beam hydride.

A compound represented by the following formula (ii) can be used as the organoaluminum compound (a-2). ^{_{R 1 n AlY 3-n ...}} (ii) wherein R ¹ is the same as R ¹ in the formula (i), n is 1
Is to 2, Y is -OR ² group, -OSiR ³ ₃ group, -O
AlR ⁴ ₂ group, -NR ⁵ ₂ group, -SiR ⁶ ₃ group or -N
(R ⁷ ) AlR ⁸ ₂ group.

R², R³, R^FourAnd R⁸Is a methyl group,
Ethyl group, isopropyl group, isobutyl group, cyclohexyl
Syl group, phenyl group, etc., R^FiveIs a hydrogen atom,
Group, ethyl group, isopropyl group, phenyl group, trime
Such as a tylsilyl group, R ⁶And R⁷Is a methyl group,
For example, an ethyl group.

More specific examples of such an organoaluminum compound include the following compounds. (1) A compound represented by the formula R ¹ _n Al (OR ² ) _3-n ,
For example, dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum methoxide, etc. (2) A compound represented by the formula R ¹ _n Al (OSiR ³ ₃ ) _3-n , for example Et ₂ Al (OSiMe ₃ ),
(iso-Bu) ₂ Al (OSiMe ₃ ), (iso-Bu) ₂ Al
(OSiEt ₃ ), such as formula (3) R ¹ _n Al (OAlR ⁴
₂ ) A compound represented by _3-n , such as Et ₂ AlOAlE
t ₂ , (iso-Bu) ₂ AlOAl (iso-Bu) _2, etc.,
(4) A compound represented by the formula R ¹ _n Al (NR ⁵ ₂ ) _3-n ,
For example, Me ₂ AlNEt ₂ , Et ₂ AlNHMe, Me ₂
AlNHEt, Et ₂ AlN (Me ₃ Si) ₂ , (iso-B
u) ₂ AlN (Me ₃ Si) _{2 and the} like, formula (5) R ¹ _n Al
A compound represented by (SiR ⁶ ₃ ) _3-n , for example (iso-B
u) ₂ AlSiMe _{3 and the} like, formula (6) R ¹ _n Al {N
A compound represented by (R ⁷ ) AlR ⁸ ₂ } _3-n , such as E
t ₂ AlN (Me) AlEt ₂ , (iso-Bu) ₂ AlN (E
t) Al (iso-Bu) _2, etc.

As the organoaluminum compound (a-2), a compound represented by the general formula M ¹ AlR ⁹ ₄ (wherein M ¹ represents Li, Na or K, and R ⁹ represents a hydrocarbon group having 1 to 15 carbon atoms) I) represented by
A complex alkyl compound of a group metal and aluminum can also be used, and specifically, LiAl (C ₂ H ₅ ) ₄ , LiAl
(C ₇ H ₁₅ ) _{4 and the} like.

Of the above, trialkylaluminum,
Dialkyl aluminum halides, dialkyl aluminum hydrides and dialkyl aluminum alkoxides are preferable, and trialkyl aluminums are particularly preferable.

The organoaluminum compound (a-
2) is used alone or in combination of two or more. Solid magnesium-aluminum composite (a)
In preparing the above, the organoaluminum compound (a-
2) is the molar ratio (ROH) of the alcohol (ROH) having 6 or more carbon atoms used to prepare the magnesium solution (a-1) and the aluminum atom (Al) contained in the organoaluminum compound (a-2). / Al) is preferably used in an amount of about 0.5 to 7, preferably 1 to 5.

The contact temperature between the magnesium solution (a-1) and the organoaluminum compound (a-2) is usually -50 to 150.
C, preferably -30 to 100C. The solid magnesium-aluminum composite (a) is prepared, for example, by adjusting the magnesium concentration in the solution to preferably 0.005-2.
While stirring the magnesium solution (a-1), which is mol / liter, more preferably 0.05 to 1 mol / liter,
The organoaluminum compound (a-2) can be gradually added dropwise to the magnesium solution (a-1) over, for example, 0.2 to 2 hours. By doing so, a solid magnesium-aluminum composite (a) having good particle properties can be obtained.

Such a solid magnesium-aluminum composite (a) does not have a reducing organic group,
It does not show reducibility. The solid titanium composite (A) is obtained by bringing the solid magnesium / aluminum composite (a) into contact with the tetravalent titanium compound (b) described later.

The tetravalent titanium compound (b) is preferably a compound represented by the following formula (iii). During ^{_{Ti (OR 10) m X 4}} -m ... (iii) formula (iii), R ¹⁰ is a hydrocarbon group, X is a halogen atom, a 0 ≦ m ≦ 3.

As such a tetravalent titanium compound (b),
Specifically, TiCl_Four, TiBr_Four, TiI_FourWhat
Which tetrahalogenated titanium; Ti (OCH₃) C
l₃, Ti (OC₂H_Five) Cl₃, Ti (On-C_FourH₉) C
l₃ , Ti (OC₂H_Five) Br₃, Ti (O-iso-C_FourH₉)
Br₃Trihalogenated alkoxy titanium such as; Ti
(OCH₃)₂Cl₂, Ti (OC₂H_Five)₂Cl₂, Ti
(On-C_FourH₉)₂Cl₂, Ti (OC₂H_Five)₂Br₂Such
Dihalogenated dialkoxy titanium: Ti (OCH₃)₃
Cl, Ti (OC₂H_Five)₃Cl, Ti (On-C_FourH₉)₃C
l, Ti (OC₂H_Five)₃Monohalogenated compounds such as Br
Examples thereof include trialkoxy titanium.

Of these, titanium tetrahalides, particularly titanium tetrachloride, are preferred. These tetravalent titanium compounds may be used alone or in combination of two or more.

In preparing the solid titanium composite (A), the tetravalent titanium compound (b) is used as the total of magnesium (Mg) and aluminum (Al) in the solid magnesium-aluminum composite (a). And the atomic ratio of titanium (Ti) in the titanium compound [Ti / (Mg
+ Al)] is 0.005 to 18, preferably 0.01
Used in an amount of ~ 15.

The contact between the solid magnesium-aluminum composite (a) and the tetravalent titanium compound (b) is preferably carried out in a hydrocarbon solvent. As the hydrocarbon solvent, the same hydrocarbon solvent as that used for preparing the magnesium solution (a-1) described above is used.

The contact between the solid magnesium-aluminum composite (a) and the tetravalent titanium compound (b) is usually 0.
It is carried out at a temperature of 150 to 150 ° C, preferably 50 to 130 ° C, more preferably 50 to 120 ° C.

The solid titanium composite (A) is obtained as described above and contains magnesium, halogen, aluminum,
Titanium and / or an alkoxy group having 6 or more carbon atoms and / or an alcohol having 6 or more carbon atoms are contained as essential components. Titanium contained in the solid titanium composite (A) is 90% or more, preferably 95% or more,
More preferably, all titanium is in the tetravalent state.

In this solid titanium composite (A),
The atomic ratio (Ti / Mg) of titanium (Ti) and magnesium (Mg) is usually 0.01 to 1.5, preferably 0.05 to 1.0, and aluminum (Al ) And magnesium (Mg) atomic ratio (Al /
(Mg) is in the range of usually 0.1 to 2.0, preferably 0.13 to 1.5, particularly preferably 0.15 to 1.2, and an alkoxy group having 6 or more carbon atoms. And / or the alcohol having 6 or more carbon atoms is usually 0.1 to 15 parts by weight, preferably 0.3 to 10 parts by weight, and more preferably 0.5 to 6 parts by weight per 1 part by weight of magnesium. is there.

Alkoxy group having 6 or more carbon atoms and / or alcohol having 6 or more carbon atoms (-OR / R-OH)
And titanium (Ti) molar ratio [(-OR / R-OH) / Ti]
Is 0.26 to 6.0, preferably 0.26 to 5.0,
More preferably, it is in the range of 0.26 to 4.0.

Further, halogen (Hal) and magnesium (M
The atomic ratio (Hal / Mg) with g) is 0.5 to 2 by weight.
0, preferably 0.5 to 15, more preferably 0.5
It is in the range of -10.

The solid titanium composite (A) desirably has a particle size of 1 to 200 μm, preferably 2 to 100 μm, and a geometric standard deviation of the particle size distribution of 1.0 to.
It is desirable to be in the range of 2.0, preferably 1.0 to 1.8.

The solid titanium catalyst component (I) comprises a solid titanium composite (A) obtained by contacting the solid magnesium-aluminum composite (a) with a tetravalent titanium compound (b), and A solid titanium / organometallic compound complex is obtained by contacting with an organometallic compound (B) containing a metal selected from Group I to Group III of the table, and the solid titanium / organometallic compound complex and oxygen are further added. It can be prepared by contacting with.

Periodic Tables I to III used here
As the organometallic compound (B) containing a metal selected from the group, for example, an organoaluminum compound, a complex alkyl compound of a group I metal and aluminum, an organometallic compound of a group II metal, and the like can be used.

Specific examples of the organoaluminum compound and the complex alkyl compound of a Group I metal and aluminum include the organoaluminum compounds and the complex alkyl of a Group I metal and aluminum exemplified in the section of the organoaluminum compound (a-2). Compounds similar to the compounds can be exemplified.

Examples of the group II metal organometallic compound include those represented by the general formula R ¹¹ R ¹² M ² (wherein R ¹¹ and R ¹² represent a hydrocarbon group having 1 to 15 carbon atoms or a halogen atom and are the same as each other). However, it is not limited to the case where each is a halogen atom. M ² represents Mg, Zn or Cd), and specific examples thereof include diethylzinc, diethylmagnesium and butyl. Examples thereof include ethyl magnesium, ethyl magnesium chloride, butyl magnesium chloride and the like.

As the organometallic compound (B), trialkylaluminum, dialkylaluminum halide,
Dialkyl aluminum hydride and dialkyl aluminum alkoxide are preferable, and trialkyl aluminum is particularly preferable.

These organometallic compounds containing a metal selected from Groups I to III of the Periodic Table may be used alone or in combination of two or more. In addition, examples of oxygen used here include oxygen gas, air, ozone, and organic peroxides.

The contact between the solid titanium composite (A) and the organometallic compound (B) can be carried out in a solvent. As such a solvent, a magnesium solution (a-1)
The same solvent as the hydrocarbon used for the preparation of can be mentioned. Of these, aliphatic hydrocarbons are preferable, and saturated aliphatic hydrocarbons having 6 to 10 carbon atoms are particularly preferable.

When the solid titanium composite (A) is contacted with the organometallic compound (B), the organometallic compound (B)
Is used in an amount of 0.1 to 100 mol, preferably 1 to 50 mol, based on 1 mol of titanium atom in the solid titanium composite (A), and the concentration of the solid titanium composite (A) is In terms of titanium atom in the solid titanium composite (A), it is 0.
1 to 100 mol / liter (solvent), preferably 0.5
˜50 mol / liter (solvent). Contact time is 1
~ 300 minutes, preferably 5 to 180 minutes, and the contact temperature is 0 to 100 ° C, preferably 10 to 50 ° C.

When the solid titanium / organometallic compound composite is brought into contact with oxygen, 0.1 mol or more, preferably 0.1 to 100, per mol atom of titanium in the solid titanium / organometallic compound composite. Molar, more preferably 0.2 to 10 mol, particularly preferably 0.3 to 3 mol of oxygen is contacted. The contact time is 1 to 300 minutes, preferably 5 to 180 minutes, and the contact temperature is 0 to 100 minutes.
C., preferably 10 to 50.degree.

The method for bringing the solid titanium / organometallic compound composite into contact with oxygen is not particularly limited. For example, (1) a solid titanium / organometallic compound composite suspended in an inert solvent. And a method of contacting with air, (2) a method of contacting solid titanium-organometallic compound complex suspended in an inert solvent with ozone, (3) a solid suspended in an inert solvent Examples thereof include a method of bringing the titanium-organometallic compound complex into contact with gaseous oxygen.

Examples of the solvent used for bringing the solid titanium-organometallic compound composite into contact with oxygen include the same solvents as the inert solvent used for preparing the magnesium solution (a-1). . Of these, aliphatic hydrocarbons are preferable, and saturated aliphatic hydrocarbons having 6 to 10 carbon atoms are particularly preferable.

When the solid titanium-organometallic compound composite is brought into contact with oxygen in this manner, it is presumed that the titanium and oxygen in the composite are bonded. The solid titanium catalyst component (I) is prepared as described above.

Examples of the organometallic compound (II) include the same compounds as the organometallic compound (B). Among these, trialkylaluminum, dialkylaluminum halide, dialkylaluminum hydride and dialkylaluminum alkoxide are preferable, and trialkylaluminum is particularly preferable.

The olefin polymerization catalyst preferably used for producing the ethylene polymer (1) and the ethylene polymer (2) forming the ethylene polymer composition according to the present invention is the solid titanium (I) described above. Catalyst component and the above (II)
It may be an olefin polymerization catalyst formed from an organometallic compound, and the solid titanium catalyst component (I),
A solid titanium catalyst component (I ′) in which an olefin is prepolymerized to a catalyst component comprising the (II) organometallic compound;
It may be an olefin polymerization catalyst formed from the (II) organometallic compound.

The olefin used in the prepolymerization is preferably ethylene alone or a small amount of α-olefin having 3 to 20 carbon atoms together with ethylene. Production of Ethylene-based Polymer (1) The ethylene-based polymer (1) forming the ethylene-based polymer composition according to the present invention may be obtained by homopolymerizing ethylene in the presence of the olefin polymerization catalyst, or It can be produced by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms.

Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene and 1-decene. , 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like.

The homopolymerization of ethylene or the copolymerization of ethylene with an α-olefin having 3 to 20 carbon atoms is carried out in the gas phase or in the slurry liquid phase. In the slurry polymerization, an inert hydrocarbon may be used as a solvent,
The olefin itself may be used as the solvent.

Specific examples of the inert hydrocarbon solvent used in the slurry polymerization include aliphatic hydrocarbons such as butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane and octadecane; cyclopentane and methylcyclopentane. , Cyclohexane,
Alicyclic hydrocarbons such as cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene; gasoline,
Examples include petroleum fractions such as kerosene and light oil. Of these inert hydrocarbon media, aliphatic hydrocarbons, alicyclic hydrocarbons, petroleum fractions and the like are preferable.

The amount of each catalyst component used in the polymerization system during the polymerization by the slurry polymerization method or the liquid phase polymerization method is such that the solid titanium catalyst component (I) and the solid titanium catalyst component (I ′) are The amount is usually about 0.00001 to 1 mmol, preferably about 0.0001 to 0.1 mmol in terms of Ti atom per volume.

The organometallic compound (II) is used in an amount of 1 to 100 with respect to 1 gram atom of titanium in the solid titanium catalyst component (I) [or the solid titanium catalyst component (I ')].
It is used in an amount of 0 mol, preferably 2-500 mol.

An organoaluminum oxy compound (aluminoxane) may be added during the polymerization. This organoaluminum oxy compound has an atomic ratio (Al / Ti) of aluminum atoms (Al) in the organoaluminum oxy compound and titanium atoms (Ti) in the solid titanium catalyst component (I) of 5 to 5. 300, preferably 10
It is used in an amount of 200, more preferably in the range of 15 to 150.

Hydrogen can be used in the production of the ethylene polymer (1). In this case, hydrogen has a hydrogen / ethylene ratio (molar ratio) of 0.5 to 20, preferably 1.0. It is used in an amount such that it ranges from -15.

When the ethylene-based polymer (1) is produced by the slurry method, the polymerization temperature is usually 0 to 200 ° C., preferably 20 to 150 ° C., and the liquid phase polymerization method is used. In this case, the polymerization temperature is usually 50 to
It is preferably in the range of 120 ° C, preferably 60 to 110 ° C.

The polymerization pressure is usually from atmospheric pressure to 100 kg / c.
It is under a pressure condition of m ² , preferably ² to 50 kg / cm ² , and the polymerization can be carried out in any of a batch system, a semi-continuous system and a continuous system.

Production of Ethylene Polymer (2) The ethylene polymer (2) forming the ethylene polymer composition according to the present invention is obtained by homopolymerizing ethylene in the presence of the above-mentioned olefin polymerization catalyst. Alternatively, it can be produced by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms.

Here, examples of the α-olefin having 3 to 20 carbon atoms include the same ones as described above. The homopolymerization of ethylene or the copolymerization of ethylene with an α-olefin having 3 to 20 carbon atoms is carried out in a gas phase or a liquid phase in a slurry state. In the slurry polymerization, an inert hydrocarbon may be used as the solvent, or the olefin itself may be used as the solvent.

Specific examples of the inert hydrocarbon solvent used in the slurry polymerization include those mentioned above. Of these inert hydrocarbon media, aliphatic hydrocarbons, alicyclic hydrocarbons, petroleum fractions and the like are preferable.

The amount of each catalyst component used in the polymerization system during the polymerization by the slurry polymerization method or the liquid phase polymerization method is such that the solid titanium catalyst component (I) and the solid titanium catalyst component (I ′) are The amount is usually about 0.00001 to 1 mmol, preferably about 0.0001 to 0.1 mmol in terms of Ti atom per volume.

The organometallic compound (II) is used in an amount of 1 to 100 with respect to 1 gram atom of titanium in the solid titanium catalyst component (I) [or the solid titanium catalyst component (I ')].
It is used in an amount of 0 mol, preferably 2-500 mol.

In addition, an organic aluminum oxy compound (aluminoxane) may be added during the polymerization. This organoaluminum oxy compound has an atomic ratio (Al / Ti) of aluminum atoms (Al) in the organoaluminum oxy compound and titanium atoms (Ti) in the solid titanium catalyst component (I) of 5 to 5. 300, preferably 10
It is used in an amount of 200, more preferably in the range of 15 to 150.

Hydrogen can be used in the production of the ethylene polymer (2). In this case, hydrogen has a hydrogen / ethylene ratio (molar ratio) of 0 to 0.5, preferably 0.
It is used in an amount such that it is in the range of 0.4.

When the ethylene polymer (2) is produced by the slurry method, the polymerization temperature is usually in the range of 0 to 200 ° C., preferably 20 to 150 ° C., and the liquid phase polymerization method is used. In this case, the polymerization temperature is usually 50 to
It is preferably in the range of 120 ° C, preferably 60 to 110 ° C.

The polymerization pressure is usually from atmospheric pressure to 100 kg / c.
It is under a pressure condition of m ² , preferably ² to 50 kg / cm ² , and the polymerization can be carried out in any of a batch system, a semi-continuous system and a continuous system.

Ethylene Polymer Composition The ethylene polymer composition according to the present invention comprises the ethylene polymer (1) and the ethylene polymer (2). The ethylene polymer (1) is 20 to 90% by weight, preferably 30 to 80% by weight, and the ethylene polymer (2) is 10 to 80% by weight, preferably 20.
It is preferably contained in a proportion of ˜70% by weight.

It is desirable that at least one of the ethylene polymer (1) and the ethylene polymer (2), and preferably both satisfy the following requirements. The value of Mw / Mn is in the range of 2 to 9, preferably 3 to 8, and more preferably 4 to 7. The value of Mz / Mw is 2 to 5, preferably 2.5 to 4.
5, more preferably in the range of 3-4, the value of g ^* , which is an index showing the ratio of long-chain branching, is 0.90.
To 1.00, preferably 0.92 to 1.00, and more preferably 0.95 to 1.00. Melt tension (MT) and melt flow rate (M
FR) is the expression log (MT) ≧ −0.4 log (MFR) +0.75, preferably the expression log (MT) ≧ −0.4 log (MFR) +0.78, more preferably the expression log (MT ) ≧ −0.4 log (MFR) +0.80, and the swell ratio exceeds 1.35, preferably 1.35.
And 2.50 or less.

In the present invention, the ethylene polymer (1) and the ethylene polymer (2) are the density (d ₁ ) of the ethylene polymer (1) and the density (d) of the ethylene polymer (2). ₂ )
And the ratio (d ₁ / d ₂ ) is more than 1, preferably 10 or more, and more preferably 100 or more.

Such an ethylene polymer composition has the following characteristics. Density is 0.940 ~
0.970 g / cm ³ , preferably 0.945 to 0.9
70 g / cm ³ , more preferably 0.950 to 0.96
It is in the range of 5 g / cm ³ .

The melt flow rate at 190 ° C. under a load of 2.16 kg is 0.005 to 1.0 g / 10 minutes, preferably 0.008 to 0.8 g / 10 minutes, more preferably 0.01 to 0.5 g. It is in the range of / 10 minutes.

The value of the molecular weight distribution Mw / Mn represented by the ratio of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is 5 to 40, preferably 7 to 30, and more preferably 9.
It is in the range of ~ 20.

The value of the molecular weight distribution Mz / Mw represented by the ratio of the Z average molecular weight (Mz) and the weight average molecular weight (Mw) is 3 to 20, preferably 4 to 18, and more preferably 5 to 1.
It is in the range of 5.

The value of g ^* , which is an index showing the ratio of long chain branching, is 0.90 to 1.00, preferably 0.92 to 1.0.
0, more preferably 0.95 to 1.00.
An ethylene polymer composition having a g ^* value in the above range has a small proportion of long chain branches in the composition, and thus a molded article obtained from this composition is excellent in rigidity and impact strength.

The ethylene polymer composition has a melt tension (MT) and a melt flow rate (MFR) expressed by the formula log (MT) ≧ −0.4 log (MFR) +0.75, preferably the formula log (MT) ≧ −0.4 log (MFR) +0.78 More preferably, the relationship expressed by the formula log (MT) ≧ −0.4 log (MFR) +0.80 is satisfied.

An ethylene polymer composition having a melt flow rate in the above range and a melt tension and a melt flow rate satisfying the relationship represented by the above formula is excellent in moldability. For example, when an inflation film is molded at high speed, bubbles are less likely to be shaken or broken, and drawdown is less likely to occur during hollow molding or sheet molding.

Furthermore, the swell ratio (SR) of the ethylene polymer composition exceeds 1.35. The swell ratio is
It is preferably more than 1.35 and not more than 2.50. The ethylene polymer composition having a swell ratio in the above range has excellent moldability.

For example, when a bottle is manufactured by blow molding, the pinch-off shape is improved, so that a bottle having excellent strength can be manufactured. Further, since the wall thickness distribution of the hollow molded body can be narrowed, the basis weight can be reduced, and the buckling strength can be increased with the same basis weight.

The ethylene polymer composition according to the present invention is
Specific high density and low molecular weight ethylene polymer (1),
A specific low density / high molecular weight ethylene polymer (2), wherein at least one of the ethylene polymers (1) and (2) has a Mw / Mn value in the range of 2 to 9; The value of Mz / Mw is in the range of 2 to 5, and the melt flow rate (MFR) and the melt tension (MT) are
Since the relationship represented by og (MT) ≧ −0.4 log (MFR) +0.75 is satisfied and the swell ratio exceeds 1.35, the melt tension and the swell ratio are high and the moldability is excellent.

Further, since the molecular weight distribution is narrow and the content of the polymer having a molecular weight remarkably larger than the average molecular weight is low, the appearance of a molded product such as fish eye is not deteriorated. Furthermore, the ethylene-based polymer composition according to the present invention,
The value of g ^* , which is an index showing the ratio of long-chain branching, is 0.90 to
Since it is in the range of 1.00, the proportion of long chain branches in the composition is small, and the resulting molded article is excellent in rigidity and impact resistance.

Further, the ethylene polymer composition according to the present invention is excellent in ESCR. The ethylene-based polymer composition of the present invention, within the range not impairing the object of the present invention, a weather resistance stabilizer, a heat resistance stabilizer, an antistatic agent, an antislip agent,
If necessary, additives such as an anti-blocking agent, an antifogging agent, a lubricant, a pigment, a dye, a nucleating agent, a plasticizer, an antiaging agent, a hydrochloric acid absorbent and an antioxidant may be added.

The ethylene-based polymer composition of the present invention can be produced by a known method, for example, the following method. (1) A method of mechanically blending the ethylene polymer (1), the ethylene polymer (2), and optionally other components with an extruder or a kneader.
(2) The ethylene-based polymer (1), the ethylene-based polymer (2), and optionally other components are added to a suitable good solvent (eg, hexane, heptane, decane, cyclohexane, benzene, toluene, xylene, etc.). A hydrocarbon solvent) and then removing the solvent. (3) A solution of the ethylene polymer (1), the ethylene polymer (2), and other components optionally added in a suitable good solvent is prepared separately, mixed, and then mixed with a solvent. How to remove. (4) A method in which the methods of (1) to (3) above are combined.

Further, the ethylene-based polymer composition of the present invention is prepared by using one or a plurality of polymerization vessels and dividing the polymerization into two or more stages under different reaction conditions to obtain the ethylene-based polymer (1) and the ethylene-based polymer composition. It can be produced by polymerizing the polymer (2) in the same polymerization vessel.

Further, a plurality of polymerization vessels are used, and the ethylene-based polymer (1) is polymerized in any one or more of the plurality of polymerization vessels, and the ethylene-based polymer is polymerized in another polymerization vessel. It can also be obtained by polymerizing the combination (2).

For example, by a two-stage polymerization method using a continuous slurry polymerization apparatus, the ethylene polymer (1) is polymerized in the first stage and the ethylene polymer (2) is polymerized in the second stage, or
Alternatively, it can be produced by polymerizing the ethylene polymer (2) in the first stage and polymerizing the ethylene polymer (1) in the second stage.

More specifically, when the ethylene polymer (1) is polymerized in the first stage and the ethylene polymer (2) is polymerized in the second stage, the density in the first stage is 0.950 to 0.980 g.
/ Cm ³ range, MFR 0.1-300g / 10
An ethylene-based polymer (1) having a range of minutes is produced. The ethylene polymer obtained in the first stage is produced so that it is present in the finally obtained ethylene polymer composition in a proportion of 20 to 90% by weight. Next, the ethylene-based polymer (2) is produced in the latter stage, and the final product (ethylene-based polymer composition) has a density of 0.940 to 0.970 g / cm ^3.
And the MFR is in the range of 0.005 to 1.0 g / 10 minutes.

The ethylene polymer (2) was polymerized in the first stage,
When the ethylene polymer (1) is polymerized in the latter stage, the density is in the range of 0.910 to 0.965 g / cm ³ and the MFR is in the range of 0.0001 to 0.1 g / 10 min in the first stage. An ethylene polymer (2) is produced. The ethylene polymer obtained in the first stage is produced so as to be present in the finally obtained ethylene polymer composition in a proportion of 10 to 80% by weight. Next, in the latter stage, an ethylene polymer (1)
Ethylene having a density in the range of 0.940 to 0.970 g / cm ³ and an MFR in the range of 0.005 to 1.0 g / 10 minutes as the final product (ethylene polymer composition). A polymer composition is obtained.

When the olefin polymer composition according to the present invention is produced by the multistage polymerization method as described above, at least the first stage of the ethylene polymer (1) and the ethylene polymer (2) is used. It is desirable that the produced ethylene polymer, preferably the ethylene polymer (1) and the ethylene polymer (2) satisfy the following items.

The value of Mw / Mn is 2 to 9, preferably 3
-8, more preferably in the range of 4-7. The value of Mz / Mw is 2-5, preferably 2.5-4.
5, more preferably in the range of 3-4, the value of g ^* , which is an index showing the ratio of long-chain branching, is 0.90.
To 1.00, preferably 0.92 to 1.00, and more preferably 0.95 to 1.00. Melt tension (MT) and melt flow rate (M
FR) is the expression log (MT) ≧ −0.4 log (MFR) +0.75, preferably the expression log (MT) ≧ −0.4 log (MFR) +0.78, more preferably the expression log (MT ) ≧ −0.4 log (MFR) +0.80, and the swell ratio exceeds 1.35, preferably 1.35.
And 2.50 or less.

The polymerization conditions in the first and second stages are the same as above. If necessary, (I) solid titanium catalyst component and / or (II) organometallic compound may be supplied to the polymerization system in the first-stage and / or second-stage polymerization.

In either the first stage or the second stage, the molecular weight of the polymer obtained by supplying or removing hydrogen can be easily adjusted. The ethylene-based polymer composition of the present invention can be molded into a desired molded product such as a drug can, a drum can, and a bottle by blow molding, vacuum molding, extrusion molding, foam molding, or the like.

[0147]

The ethylene polymer composition according to the present invention comprises a high density, low molecular weight ethylene polymer (1) having specific physical properties and a low density, high molecular weight ethylene polymer having specific physical properties. Since it is formed from the combined body (2), it is excellent in moldability, impact strength and ESCR, and also in a good balance between them.

[0148]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited to these examples.

In the present invention, the physical properties of the ethylene polymer composition were evaluated as follows. [Melt tension (MT)] Melt tension is a stress (g) when a molten polymer is stretched at a constant speed.
Is determined by measuring That is, the polymer powder is melted by a usual method and then pelletized to obtain a measurement sample, using an MT measuring instrument manufactured by Toyo Seiki Seisakusho, a resin temperature of 200 ° C., an extrusion speed of 15 mm / min, and a winding speed of 10
~ 20 m / min, nozzle diameter 2.09 mmφ, nozzle length 8
mm conditions. When pelletizing,
0.05% by weight of tri (2,4-di-t-butylphenyl) phosphate as a secondary antioxidant and n-octadecyl-3- (4'-hydroxy-3 ', as a heat resistance stabilizer in advance. Five'-
0.1% by weight of di-t-butylphenyl) propionate,
0.05% calcium stearate as a hydrochloric acid absorbent
% By weight.

[Swell ratio (SR)] Nozzle diameter (D ₀ ) = 3.0 m on Capillograph-IB manufactured by Toyo Seiki Seisaku-sho, Ltd.
A nozzle of mφ and length (L) = 90 mm is attached, and the barrel (portion where sample is put) is heated to 200 ° C. and held. Put about 10g of sample in the barrel, attach the piston,
Degas and preheat for 6 minutes. After preheating, the sample is extruded at a predetermined shear rate, and the strand diameter (D _i ) 15 mm below the nozzle exit is measured with a laser beam. Thus determining the ratio between the measured strand diameter (D _i) and nozzle diameter _{(D 0) (SR i =} D i / D 0) and. In addition, in Example 1 and Comparative Examples 1 and 2, the shear rate was 200.
measured in sec ^-1, in Example 2 and Comparative Example 3 were measured at a shear rate of 1,000 sec ^-1.

[Izod impact strength (IZ)] JIS
The test was conducted according to K7110. However, Example 1 and Comparative Examples 1 and 2 are at -40 ° C., and Example 2 and Comparative Example 3 are
Was performed at 23 ° C.

[ESCR] The test was conducted according to JIS K6760.

[0153]

[Catalyst preparation example] Preparation of solid titanium catalyst component (1) 4.8 g of anhydrous magnesium chloride, 19.5 g of 2-ethylhexanol and 200 ml of decane were heated at 140 ° C for 3 hours to obtain a uniform solution. This solution is stirred at 20 ° C
At 60 ° C., a mixed solution of 60 mmol of triethylaluminum and 52 ml of decane was added dropwise over 30 minutes, then heated to 80 ° C. over 2 hours and heated for 2 hours. After that, the solid part is separated by filtration, and the decane is mixed with 200 ml to 1
By washing twice, a solid magnesium-aluminum composite was obtained.

The solid magnesium-aluminum complex thus obtained was resuspended in 200 ml of decane, 400 mmol of titanium tetrachloride was added, and the mixture was reacted at 80 ° C. for 2 hours, and then with hexane. Thorough washing was performed to obtain a hexane suspension of the solid titanium composite (A).

The composition of the solid titanium composite (A) is as follows: titanium 7.3% by weight, magnesium 8.8% by weight, aluminum 5.0% by weight, chlorine 53% by weight, 2-ethylhesoxy group 10.5% by weight. Met.

Then, in a four-necked flask having an internal volume of 200 ml, hexane 100 m was added at room temperature (26 ° C.) under nitrogen substitution.
Then, 1 ml of triethylaluminum was charged in an amount of 3 mmol in terms of aluminum atoms, and the solid titanium composite (A) was charged in an amount of 1 mmol in terms of an amount of titanium atoms, and stirring was continued at room temperature for 1 hour. After completion of stirring, solid-liquid separation was performed by decantation, hexane was added, and the mixture was stirred, and then the washing operation of removing the supernatant by decantation was repeated three times.

After resuspending with 100 ml of hexane, 1
58.4 ml of dry air containing 1.2 Nml of oxygen was charged into the gas phase portion, and the mixture was stirred at room temperature for 1 hour. When the volume reduction of the gas phase portion during this period was measured using a gas buret, it was 8
The oxygen absorption amount was 7.3 Nml.

After completion of the stirring, the solid-liquid is separated by decantation, hexane is added and stirred, and then the washing operation of removing the supernatant by decantation is repeated twice to obtain a solid titanium catalyst component (1). It was

Preparation of solid catalyst component (2) In a four-necked flask having an internal volume of 400 ml, 30 mmol of anhydrous magnesium chloride was suspended in 150 ml of n-decane,
While stirring, 180 mmol of ethanol was added dropwise over 1 hour, and the mixture was reacted at room temperature for 1 hour. It became a white powder in which the raw material magnesium chloride was swollen. Then, 84 mmol of diethyl aluminum monochloride was added dropwise at room temperature, and the mixture was reacted at 30 ° C. for 1 hour. Then, after adding 300 mmol of titanium tetrachloride, the mixture was heated and stirred at 80 ° C. for 3 hours. After completion of the reaction, solid-liquid separation was performed, and the obtained solid part was n-
It was washed with 2 liters of decane. Thus, the solid catalyst component (2) was obtained.

[0160]

Example 1 Using a continuous slurry polymerization apparatus, two-stage polymerization was carried out as follows. First, in the first stage, total pressure 6.2
Ethylene homopolymerization was performed at kg / cm ² -G and a polymerization temperature of 85 ° C. The solid titanium catalyst component (1) prepared above was continuously supplied at a rate of 2.0 mmol / hr in terms of titanium atom, and triethylaluminum at a rate of 63 mmol / hr. Further, ethylene was continuously supplied at a rate of 15.7 kg / hr and hexane was continuously supplied at a rate of 45 liters / hr. Hydrogen and nitrogen were fed continuously with ethylene to maintain a constant gas composition during the polymerization [gas composition; hydrogen /
Ethylene = 1.6 (molar ratio), ethylene concentration = 34.8
Mol%]. The obtained ethylene polymer has a density of 0.9.
It was 69 g / cm ³ and the MFR was 8.1 g / 10 minutes.

Next, after removing the hydrogen from the polymerization solution at the first stage, it was transferred to the second stage polymerization apparatus, and in the presence of the polymerization solution, the total pressure was 3.2 kg / cm ² -G and the polymerization temperature was 70 ° C. Ethylene / 1-butene copolymerization was performed. 12.3k ethylene
g / hr, 1-butene 320 g / hr, hexane 48
It was continuously fed at a rate of liter / hr. Further, in order to maintain a constant gas composition during the polymerization, hydrogen and nitrogen were continuously supplied together with ethylene and 1-butene [gas composition; 1-butene / ethylene = 0.020 (molar ratio), hydrogen / ethylene = 0.025 (molar ratio), ethylene concentration = 5
9.0 mol%].

The ethylene-based polymer composition obtained had a density of 0.955 g / cm ³ and an MFR of 0.031 g.
It was / 10 minutes. The polymerization amount ratio of the first stage and the second stage is 5
It was 6:44. Table 1 shows the physical properties and the like of the ethylene polymer (1), the ethylene polymer (2) and the ethylene polymer composition.

[0163]

Example 2 Using the same continuous slurry polymerization apparatus as in Example 1, two-stage polymerization was carried out as follows.

First, in the first stage, the total pressure is 7.2 kg / cm ² -G.
Ethylene homopolymerization was carried out at a polymerization temperature of 85 ° C. The solid titanium catalyst component (1) prepared above was continuously supplied at a rate of 2.3 mmol / hr in terms of titanium atom, and triethylaluminum at a rate of 44 mmol / hr. Also,
Ethylene was continuously supplied at a rate of 15.4 kg / hr and hexane was continuously supplied at a rate of 44 liters / hr. Hydrogen and nitrogen were continuously fed together with ethylene in order to maintain a constant gas composition during the polymerization [gas composition; hydrogen / ethylene =
2.7 (molar ratio), ethylene concentration = 21.3 mol%].
The ethylene-based polymer obtained had a density of 0.972 g / c.
m ³ and MFR was 60 g / 10 minutes.

Next, after dehydrogenating the polymerization solution in the first stage, the solution was transferred to the second stage polymerization apparatus, and in the presence of the polymerization solution, the total pressure was 3.2 kg / cm ² -G and the polymerization temperature was 80 ° C. Ethylene homopolymerization was performed. 12.6 kg / h of ethylene
r and hexane were continuously supplied at a rate of 49 l / hr. Further, in order to maintain a constant gas composition during the polymerization, hydrogen and nitrogen were continuously supplied together with ethylene [gas composition; hydrogen / ethylene = 0.17 (molar ratio), ethylene concentration = 43.5 mol%]. .

The ethylene polymer composition obtained had a density of 0.966 g / cm ³ and an MFR of 0.31 g / cm ^3.
It was 10 minutes. The polymerization amount ratio of the first stage and the second stage is 55:
It was 45. Table 1 shows the physical properties of the ethylene polymer and the ethylene polymer composition.

[0167]

Comparative Example 1 Using the same continuous slurry polymerization apparatus as in Example 1, two-stage polymerization was carried out as follows.

First, in the first stage, the total pressure is 4.9 kg / cm ² -G
Ethylene homopolymerization was carried out at a polymerization temperature of 85 ° C. 1. The solid catalyst component (2) prepared above is converted to titanium atom in terms of 2.
3 mmol / hr, triethylaluminum 45 mm
It was continuously supplied at a ratio of ol / hr. Also, ethylene is 15.7 kg / hr and hexane is 45 liters / hr.
Was continuously supplied. Hydrogen and nitrogen were continuously supplied together with ethylene in order to maintain a constant gas composition during the polymerization [gas composition; hydrogen / ethylene = 4.2 (molar ratio), ethylene concentration = 16.5 mol%]. The obtained ethylene polymer had a density of 0.971 g / cm ³ and an MFR of 43 g / 10 minutes.

Next, after removing the hydrogen from the polymerization solution at the first stage, it was transferred to the second-stage polymerization apparatus, and in the presence of the polymerization solution, at a total pressure of 2.6 kg / cm ² -G and a polymerization temperature of 70 ° C. Ethylene / 1-butene copolymerization was performed. 12.3k ethylene
g / hr, 1-butene 160 g / hr, hexane 48
It was continuously fed at a rate of liter / hr. Further, in order to maintain a constant gas composition during the polymerization, hydrogen and nitrogen were continuously supplied together with ethylene and 1-butene [gas composition; 1-butene / ethylene = 0.020 (molar ratio), hydrogen / ethylene = 0.10 (molar ratio), ethylene concentration = 3
4.7 mol%].

The ethylene-based polymer composition obtained had a density of 0.956 g / cm ³ and an MFR of 0.039 g.
It was / 10 minutes. The polymerization amount ratio of the first stage and the second stage is 5
It was 6:44. Table 1 shows the physical properties and the like of the ethylene polymer (1), the ethylene polymer (2) and the ethylene polymer composition.

[0171]

Comparative Example 2 Using the same continuous slurry polymerization apparatus as in Example 1, two-stage polymerization was carried out as follows.

First, in the first stage, the total pressure is 7.0 kg / cm ² -G
Ethylene homopolymerization was carried out at a polymerization temperature of 85 ° C. 1. The solid catalyst component (2) prepared above is converted to titanium atom in terms of 2.
3 mmol / hr, 44 mm triethylaluminum
It was continuously supplied at a ratio of ol / hr. Also, ethylene is 15.4 kg / hr and hexane is 44 liters / hr.
Was continuously supplied. Hydrogen and nitrogen were continuously supplied together with ethylene in order to maintain a constant gas composition during the polymerization [gas composition; hydrogen / ethylene = 6.0 (molar ratio), ethylene concentration = 14 mol%]. The obtained ethylene-based polymer had a density of 0.973 g / cm ³ , and M
FR was 120 g / 10 minutes.

Next, after dehydrogenating the polymerization solution in the first stage, it was transferred to the second stage polymerization apparatus, and in the presence of the polymerization solution, the total pressure was 3.0 kg / cm ² -G and the polymerization temperature was 80 ° C. Ethylene / 1-butene copolymerization was performed. Ethylene 12.6k
g / hr, 1-butene 100 g / hr, hexane 49
It was continuously fed at a rate of liter / hr. Further, in order to maintain a constant gas composition during the polymerization, hydrogen and nitrogen were continuously supplied together with ethylene and 1-butene [gas composition; 1-butene / ethylene = 0.010 (molar ratio), hydrogen / ethylene = 0.20 (molar ratio), ethylene concentration = 3
0.0 mol%].

The ethylene polymer composition obtained had a density of 0.964 g / cm ³ and an MFR of 0.35 g / cm ^3.
It was 10 minutes. The polymerization amount ratio of the first stage and the second stage is 55:
It was 45. Table 1 shows the physical properties and the like of the ethylene polymer (1), the ethylene polymer (2) and the ethylene polymer composition.

[0175]

[Table 1]

Claims (6)

[Claims] 1. A homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, which has a density of 0.950 to 0.980 g / cm ³ . Ethylene polymer (1) having a melt flow rate in the range of 0.1 to 300 g / 10 minutes at 190 ° C. and a load of 2.16 kg; 20 to 90% by weight, and a homopolymer of ethylene or ethylene and the number of carbon atoms. Is 3
To 20-α-olefin copolymer having a density in the range of 0.910 to 0.965 g / cm ³ ,
An ethylene polymer (2) having a melt flow rate in the range of 0.0001 to 0.1 g / 10 min at 0 ° C. and a load of 2.16 kg; 80 to 10% by weight, and the ethylene polymer (1 ) And at least one of the ethylene-based polymers (2) has a Mw / Mn value in the range of 2 to 9, and a Mz / Mw value in the range of 2 to 5, indicating the proportion of long-chain branching. The value of g ^* which is an index is 0.90
The melt tension (MT) and melt flow rate (M
FR) satisfies the relationship represented by the following formula, and has a log (MT) ≧ −0.4 log (MFR) +0.75 swell ratio of more than 1.35, which is (i) The ratio (d ₁ / d ₂ ) of the density (d ₁ ) of the ethylene polymer ( ₁ ) and the density (d ₂ ) of the ethylene polymer (2) exceeds 1, and (ii) the density is 0. In the range of 0.940 to 0.970 g / cm ³ ,
(Iii) the melt flow rate at 190 ° C. under a load of 2.16 kg is in the range of 0.005 to 1.0 g / 10 minutes, (iv) the value of Mw / Mn is in the range of 5 to 40,
(V) The value of Mz / Mw is in the range of 3 to 20, and (vi)
The value of g ^* , which is an index showing the ratio of long-chain branching, is 0.90 to
An ethylene-based polymer composition characterized by being in the range of 1.00. 2. The ethylene polymer (1) and the ethylene polymer (2) are (I) (A) (a) (a-1) halogen-containing magnesium compound having 6 or more carbon atoms. A magnesium solution formed from an alcohol and a hydrocarbon solvent and (a-2) an organoaluminum compound are brought into contact with each other to obtain magnesium, halogen, aluminum and a carbon atom having 6 carbon atoms.
A solid magnesium-aluminum composite containing the above alkoxy group and / or an alcohol having 6 or more carbon atoms and (b) a tetravalent titanium compound are brought into contact with each other. The valence of titanium contained is substantially tetravalent, [alkoxy group having 6 or more carbon atoms and / or alcohol having 6 or more carbon atoms] / Ti
By contacting a solid titanium composite having a (molar ratio) in the range of 0.26 to 6.0 with (B) an organometallic compound containing a metal selected from Group I to Group III of the periodic table. A solid titanium catalyst component obtained by contacting the obtained solid titanium / organometallic compound composite with oxygen, and (II) an organometallic compound containing a metal selected from Groups I to III of the periodic table. The ethylene-based polymer composition according to claim 1, which is produced by using an olefin polymerization catalyst containing 3. A plurality of polymerization vessels are used, and the ethylene-based polymer (1) is polymerized in any one or more of the plurality of polymerization vessels, and the ethylene-based polymer is polymerized in another polymerization vessel. The ethylene-based polymer composition according to claim 1 or 2, which is obtained by polymerizing the polymer (2). 4. A polymer obtained by polymerizing the ethylene polymer (1) in the first stage and polymerizing the ethylene polymer (2) in the second stage by using a two-stage polymerization method. Alternatively, the ethylene-based polymer composition according to item 2. 5. The polymer is obtained by polymerizing the ethylene polymer (2) in the first stage and polymerizing the ethylene polymer (1) in the second stage by using a two-stage polymerization method. Alternatively, the ethylene-based polymer composition according to item 2. 6. The ethylene polymer produced in at least the first stage among the ethylene polymer (1) and the ethylene polymer (2) has a Mw / Mn value in the range of 2 to 9, The value of Mz / Mw is in the range of 2 to 5, and the value of g ^* which is an index showing the ratio of long chain branching is 0.90.
The melt tension (MT) and melt flow rate (M
FR) and the relationship represented by the following formula are satisfied, and log (MT) ≧ −0.4 log (MFR) +0.75 swell ratio exceeds 1.35. 6. Ethylene polymer composition.