JP2004002899A - Ethylene based copolymer composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ethylene based copolymer composition excellent in moldability and from which a film excellent in transparency, mechanical strength, and antiblocking property can be produced. <P>SOLUTION: The ethylene based copolymer composition includes [A] a copolymer of ethylene and a 3-20C α-olefin having melt flow rate (MFR) and a maximum peak of a melting point and a melt tension (MT) in DSC within a predetermined range, and in which the melt tension (MT) and melt flow rate (MFR) satisfy the relation shown by MT≤2.2×MFR<SP>-0.84</SP>and [B] a low density polyethylene by a high-pressure radical polymerization method with melt flow rates ranging from 0.1 to 50g/10min, and the weight ratio of the above [A] and [B] is within the range from 99:1 to 60:40. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an ethylene-based copolymer composition, and more specifically, can produce a film having excellent transparency and mechanical strength as compared with a conventionally known ethylene-based copolymer or an ethylene-based copolymer composition. The present invention also relates to a novel ethylene copolymer composition having excellent moldability.

Ethylene copolymers are molded by various molding methods and are used for various purposes. The properties required of the ethylene-based copolymer vary depending on the molding method and application. For example, when trying to mold an inflation film at high speed, in order to stably perform high-speed molding without bubble fluctuation or tearing, select an ethylene-based copolymer that has a large melt tension for its molecular weight. Must. Similar properties are needed to prevent sagging or tearing in blow molding or to minimize width loss in T-die molding. In addition, in such extrusion molding, it is necessary to reduce the stress of the ethylene-based copolymer under high shear during extrusion from the economical viewpoint of improving the quality of molded articles and reducing power consumption during molding.

By the way, low-density polyethylene produced by a high-pressure radical method has a higher melt tension than an ethylene-based copolymer produced using a Ziegler-type catalyst, and is therefore used for applications such as films and hollow containers. However, high-pressure radical method low-density polyethylene is inferior in mechanical strength such as tensile strength, tear strength or impact strength, and is also inferior in heat resistance, stress crack resistance and the like.

On the other hand, there has been proposed a method of improving the moldability by improving the melt tension and swelling ratio (die swell ratio) of an ethylene polymer obtained using a Ziegler-type catalyst, particularly a titanium-based catalyst (for example, Patent Document 1). 1, 2, etc.).

However, in general, ethylene-based polymers obtained using a titanium-based catalyst, particularly low-density ethylene-based copolymers, have a problem that the composition distribution is wide and molded articles such as films are sticky.

In addition, among ethylene polymers produced using a Ziegler-type catalyst, an ethylene polymer obtained using a chromium-based catalyst has a relatively low melt tension, but has a disadvantage of poor thermal stability. . This is presumably because the chain ends of the ethylene polymer produced using the chromium-based catalyst tend to be unsaturated bonds.

Among the Ziegler-type catalyst systems, it is known that an ethylene-based polymer obtained by using a metallocene catalyst system has advantages such as a narrow composition distribution and a molded product such as a film having little stickiness. However, for example, Patent Document 3 discloses that an ethylene-based polymer obtained by using a zirconocene compound composed of a cyclopentadienyl derivative as a catalyst contains one terminal unsaturated bond per molecule. Like the ethylene polymer obtained using the catalyst, it is expected that thermal stability is poor. In addition, since the molecular weight distribution is narrow, there is a concern that fluidity during extrusion molding is poor.

For this reason, if an ethylene polymer with excellent melt tension, low stress in the high shear region, good thermal stability, excellent mechanical strength, and a narrow composition distribution appears, its industrial value will be Extremely large.

The present inventors have proposed a catalyst for olefin polymerization comprising (a) a transition metal compound of Group IV of the periodic table containing a ligand having a specific cyclopentadienyl skeleton, and (b) an organoaluminum oxy compound. It has been found below that an ethylene / α-olefin copolymer obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms has excellent heat stability and a narrow composition distribution. As a result of further research, an ethylene-based copolymer composition obtained by blending this ethylene / α-olefin copolymer with a specific low-density polyethylene obtained by a high-pressure radical polymerization method is molded. The inventors have found that the resulting film has excellent transparency and mechanical strength, and have completed the present invention.
JP-A-56-90810 JP-A-60-106806 JP-A-60-35007

課題 An object of the present invention is to provide an ethylene copolymer composition which is excellent in moldability, transparency, and can produce a film excellent in mechanical strength.

The ethylene copolymer composition according to the present invention,
[A] a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms,
(I) the density (d) is in the range of 0.880 to 0.960 g / cm ³ ;
(Ii) a melt flow rate (MFR) at 190 ° C. and a load of 2.16 kg is in a range of 0.01 to 200 g / 10 minutes;
(Iii) The maximum peak (T (° C.)) of the melting point in DSC and the density (d) are:
T <400 × d-250
Satisfy the relationship indicated by
(Iv) The melt tension (MT (g)) at 190 ° C. and the melt flow rate (MFR)
MT ≦ 2.2 × MFR ^-0.84
Satisfy the relationship indicated by
(V) The decane-soluble portion (W (% by weight)) at 23 ° C. and the density (d) are:
When MFR ≦ 10 g / 10 minutes,
W <80 × exp (−100 (d−0.88)) + 0.1
When MFR> 10g / 10min,
W <80 × (MFR-9) ^0.26 × exp (−100 (d−0.88)) + 0.1
An ethylene / α-olefin copolymer satisfying the relationship represented by:
[B] low-density polyethylene obtained by a high-pressure radical method,
(I) the melt flow rate (MFR) is in the range of 0.1 to 50 g / 10 minutes,
(Ii) The molecular weight distribution (Mw / Mn: Mw = weight average molecular weight, Mn = number average molecular weight) measured by GPC and the melt flow rate (MFR) are:
7.5 × log (MFR) −1.2 ≦ Mw / Mn ≦ 7.5 × log (MFR) +12.5
High-pressure radical method low-density polyethylene that satisfies the relationship shown in
The weight ratio ([A]: [B]) of the ethylene / α-olefin copolymer [A] and the high-pressure radical method low-density polyethylene [B] is within the range of 99: 1 to 60:40. It is characterized by having.

The ethylene-based copolymer composition of the present invention is obtained by blending an ethylene / α-olefin copolymer [A] having a narrow composition distribution and good thermal stability with a high-pressure radical method low-density polyethylene [B]. Therefore, since the melt tension is high and the stress in the high shear region is low, the moldability is excellent. From such an ethylene copolymer composition, a film having excellent transparency, mechanical strength, heat sealability, hot tack, heat resistance, and blocking resistance can be produced.

Hereinafter, the ethylene copolymer composition according to the present invention will be specifically described. The ethylene copolymer composition according to the present invention comprises an ethylene / α-olefin copolymer [A] and a high pressure radical method low density polyethylene [B].

[Ethylene / α-olefin copolymer [A]]
The ethylene / α-olefin copolymer [A] constituting the ethylene-based copolymer composition according to the present invention is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Examples of the α-olefin having 3 to 20 carbon atoms used for copolymerization with ethylene include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, Examples thereof include 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

In the ethylene / α-olefin copolymer [A], the constituent unit derived from ethylene is present in an amount of 55 to 99% by weight, preferably 65 to 98% by weight, more preferably 70 to 96% by weight, and carbon It is desirable that the structural unit derived from the α-olefin of Formulas 3 to 20 is present in an amount of 1 to 45% by weight, preferably 2 to 35% by weight, more preferably 4 to 30% by weight.

The composition of the ethylene / α-olefin copolymer is usually ¹³ C-NMR spectrum of a sample obtained by uniformly dissolving about 200 mg of the copolymer in 1 ml of hexachlorobutadiene in a 10 mmφ sample tube, at a measurement temperature of 120 ° C. It is determined by measuring under measurement conditions of a measurement frequency of 25.05 MHz, a spectrum width of 1500 Hz, a pulse repetition time of 4.2 sec, and a pulse width of 6 μsec.

The ethylene / α-olefin copolymer [A] used in the present invention has the following properties (i) to (v).
(I) Density (d) is it is in the range of 0.880~0.960g / cm ^3, preferably 0.890~0.935g / cm ^3, more preferably 0.905~0.930g / cm It is desirable to be in the range of ³ .

The density (d) was determined by measuring the melt flow rate (MF) at 190 ° C. under a load of 2.16 kg.
R) The strand obtained at the time of measurement was heat-treated at 120 ° C. for 1 hour, gradually cooled to room temperature over 1 hour, and then measured with a density gradient tube.

(Ii) The melt flow rate (MFR) is in the range of 0.01 to 200 g / 10 minutes, preferably in the range of 0.05 to 50 g / 10 minutes, and more preferably in the range of 0.1 to 10 g / min. It is desirable.

The melt flow rate (MFR) is measured at 190 ° C. under a load of 2.16 kg according to ASTM D1238-65T.
(Iii) The temperature (T (° C.)) and the density (d) at the maximum peak position in the endothermic curve measured by the differential scanning calorimeter (DSC) are as follows:
T <400 × d-250
Satisfies the relationship indicated by
Preferably T <450 × d-297
More preferably, T <500 × d-344.
Particularly preferably, T <550 × d-391
It is desirable to satisfy the relationship shown by

The temperature (T (° C.)) at the maximum peak position in the endothermic curve was determined by filling about 5 mg of a sample in an aluminum pan, heating the temperature to 200 ° C. at 10 ° C./min, holding at 200 ° C. for 5 minutes, and then 20 ° C./min. At room temperature and then at 10 ° C./min. The measurement was performed using a DSC-7 type device manufactured by PerkinElmer.

(Iv) The melt tension (MT (g)) and the melt flow rate (MFR)
MT ≦ 2.2 × MFR ^-0.84
Satisfies the relationship indicated by.

The melt tension (MT (g)) is determined by measuring the stress when the molten polymer is stretched at a constant speed. That is, the produced polymer powder is melted by a usual method and then pelletized to prepare a measurement sample. Using an MT measuring device manufactured by Toyo Seiki Seisaku-sho, the resin temperature is 190 ° C., the extrusion speed is 15 mm / min, and the winding speed is 10 to 20 m / min. , Nozzle diameter 2.09mmφ
And a nozzle length of 8 mm. At the time of pelletization, 0.05% by weight of tri (2,4-di-t-butylphenyl) phosphate as a secondary antioxidant was previously added to the ethylene / α-olefin copolymer [A], which was stable against heat. 0.1% by weight of n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate as an agent and 0.05% by weight of calcium stearate as a hydrochloric acid absorbent did.

(V) n-decane soluble component amount fraction (W (% by weight)) and density (d) at 23 ° C.
When MFR ≦ 10 g / min,
W <80 × exp (−100 (d−0.88)) + 0.1
Preferably, W <60 × exp (−100 (d−0.88)) + 0.1
More preferably, W <40 × exp (−100 (d−0.88)) + 0.1
When MFR> 10 g / min,
W <80 × (MFR-9) ^0.26 × exp (−100 (d−0.88)) + 0.1
Satisfies the relationship indicated by.

The amount of the n-decane soluble component of the ethylene / α-olefin copolymer (the smaller the soluble component, the narrower the composition distribution) was measured by adding about 3 g of the copolymer to 450 ml of n-decane, After melting at 23 ° C., the mixture is cooled to 23 ° C., the n-decane insoluble portion is removed by filtration, and the n-decane soluble portion is recovered from the filtrate.

As described above, the relationship between the temperature (T) and the density (d) at the maximum peak position in the endothermic curve measured by the differential scanning calorimeter (DSC), and the n-decane soluble component amount fraction (W) and the density ( It can be said that the ethylene / α-olefin copolymer [A] according to the present invention, which has the above-mentioned relationship with d), has a narrow composition distribution.

Further, in the ethylene / α-olefin copolymer [A], the number of unsaturated bonds present in the molecule is 0.5 or less per 1000 carbon atoms, and 1 or less per polymer molecule. It is desirable.

In addition, the quantification of the unsaturated bond is performed by using ¹³ C-NMR, using a signal belonging to a group other than the double bond, that is, a signal in the range of 10 to 50 ppm, and a signal belonging to the double bond, that is, a signal in the range of 105 to 150 ppm. Are determined from the integral curve and determined from the ratio.

Also, the following formula

[In the formula, PE indicates the mole fraction of the ethylene component in the copolymer, Po indicates the mole fraction of the α-olefin component, and PoE indicates the mole fraction of the α-olefin / ethylene chain in all dyad chains. B ratio represented by the following formula:
1.00 ≦ B
Preferably, 1.01 ≦ B ≦ 1.50
More preferably, 1.01 ≦ B ≦ 1.30
It is characterized by being within the range satisfying.

The B value is an index indicating the distribution state of each monomer component in the copolymer chain, GJRay (Macromolecules, 10 , 773 (1977)), JC, Randall (Macromolecules, 15 , 353, (1982)), J .Polymer Science, Polymer Physics Ed., 11 , 275 (1973)), K. Kimura (Polymer, 25, 441 (1984)), et al. . The larger the B value, the smaller the number of block-like chains, indicating that the copolymer has a uniform distribution of ethylene and α-olefin and a narrow composition distribution.

The composition distribution B value was obtained by measuring a ¹³ C-NMR spectrum of a sample in which about 200 mg of a copolymer was uniformly dissolved in 1 ml of hexachlorobutadiene in a 10 mmφ sample tube, usually at a measurement temperature of 120 ° C. and a measurement frequency of Measured under the measurement conditions of 25.05 MHz, spectrum width of 1500 Hz, filter width of 1500 Hz, pulse repetition time of 4.2 seconds, pulse width of 7 μs, and integration number of 2000 to 5000 times, and PE, Po, and PoE are obtained from the spectrum. It was calculated by the following.

The ethylene / α-olefin copolymer [A] having the above-mentioned properties is prepared by mixing (a) a transition metal compound and (b) an organoaluminum oxy compound as described below in the presence of an olefin polymerization catalyst. Can be produced by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms such that the density of the obtained copolymer is 0.880 to 0.960 g / cm ^3. In the presence of (a) a transition metal compound, (b) an organoaluminum oxy compound, (c) a carrier, and, if necessary, (d) an olefin polymerization catalyst formed from the organoaluminum compound, ethylene and ethylene are used. can be prepared by the α- olefin having 3 to 20 carbon atoms, it is copolymerized such that the density of the copolymer obtained becomes 0.880~0.960g / cm ³ .

遷移 The transition metal compound (a) (hereinafter sometimes referred to as “component (a)”) used in the present invention is a transition metal compound represented by the following formula [I].

MLx ... [I]
(In the formula [I], M is a transition metal selected from Group IVB of the periodic table, L is a ligand coordinated to the transition metal atom M, and at least two of these ligands L Is a substituted cyclopentadienyl group having at least one group selected from the group consisting of a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, and a hydrocarbon group having 3 to 10 carbon atoms. And the ligand L other than a (substituted) cyclopentadienyl group is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a halogen atom, a trialkylsilyl group or a hydrogen atom, and X is a transition metal. It is the valence of M.)
In the above formula [I], M is a transition metal selected from Group IVB of the periodic table, specifically, zirconium, titanium or hafnium, and preferably zirconium.

L is a ligand that coordinates to the transition metal atom M, and at least two of these ligands L are a cyclopentadienyl group, a methylcyclopentadienyl group, an ethylcyclopentadienyl group, Or a substituted cyclopentadienyl group having at least one substituent selected from a hydrocarbon group having 3 to 10 carbon atoms, and the ligand L other than the (substituted) cyclopentadienyl group has 1 to 3 carbon atoms. 12 hydrocarbon groups, alkoxy groups, aryloxy groups, halogen atoms, trialkylsilyl groups or hydrogen atoms.

The substituted cyclopentadienyl group may have two or more substituents, and the two or more substituents may be the same or different. When the substituted cyclopentadienyl group has two or more substituents, at least one substituent may be a hydrocarbon group having 3 to 10 carbon atoms, and the other substituents may be a methyl group or an ethyl group. Alternatively, it is a hydrocarbon group having 3 to 10 carbon atoms. The substituted cyclopentadienyl groups coordinated to M may be the same or different.

Specific examples of the hydrocarbon group having 3 to 10 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group. More specifically, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group, decyl group and the like Alkyl group; cycloalkyl group such as cyclopentyl group and cyclohexyl group; aryl group such as phenyl group and tolyl group; aralkyl group such as benzyl group and neophyl group.

Among these, an alkyl group is preferable, and an n-propyl group and an n-butyl group are particularly preferable. In the present invention, the (substituted) cyclopentadienyl group coordinated to the transition metal is preferably a substituted cyclopentadienyl group, more preferably a cyclopentadienyl group substituted by an alkyl group having 3 or more carbon atoms. A substituted cyclopentadienyl group is more preferred, and a 1,3-substituted cyclopentadienyl group is particularly preferred.

In the above formula [I], the ligand L other than the (substituted) cyclopentadienyl group coordinated to the transition metal atom M is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a halogen atom. , A trialkylsilyl group or a hydrogen atom.

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group and the like, and more specifically, a methyl group, an ethyl group, an n-propyl group, and an isopropyl group. Groups, alkyl groups such as n-butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, octyl group, 2-ethylhexyl group and decyl group; cycloalkyl groups such as cyclopentyl group and cyclohexyl group Groups; aryl groups such as phenyl group and tolyl group; and aralkyl groups such as benzyl group and neophyl group.

Examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, t-butoxy, pentoxy, hexoxy, octoxy and the like. be able to.

Examples of the aryloxy group include a phenoxy group. Examples of the halogen atom include fluorine, chlorine, bromine, and iodine.

Examples of the trialkylsilyl group include a trimethylsilyl group, a triethylsilyl group, and a triphenylsilyl group.
Examples of the transition metal compound represented by the general formula [I] include:
Bis (cyclopentadienyl) zirconium dichloride,
Bis (methylcyclopentadienyl) zirconium dichloride,
Bis (ethylcyclopentadienyl) zirconium dichloride,
Bis (n-propylcyclopentadienyl) zirconium dichloride,
Bis (n-butylcyclopentadienyl) zirconium dichloride,
Bis (n-hexylcyclopentadienyl) zirconium dichloride,
Bis (methyl-n-propylcyclopentadienyl) zirconium dichloride,
Bis (methyl-n-butylcyclopentadienyl) zirconium dichloride,
Bis (dimethyl-n-butylcyclopentadienyl) zirconium dichloride,
Bis (n-butylcyclopentadienyl) zirconium dibromide,
Bis (n-butylcyclopentadienyl) zirconium methoxychloride,
Bis (n-butylcyclopentadienyl) zirconium ethoxycyclolide,
Bis (n-butylcyclopentadienyl) zirconium butoxycyclolide,
Bis (n-butylcyclopentadienyl) zirconium ethoxide,
Bis (n-butylcyclopentadienyl) zirconium methyl chloride,
Bis (n-butylcyclopentadienyl) zirconium dimethyl,
Bis (n-butylcyclopentadienyl) zirconium benzyl chloride,
Bis (n-butylcyclopentadienyl) zirconium dibenzyl,
Bis (n-butylcyclopentadienyl) zirconium phenyl chloride,
Bis (n-butylcyclopentadienyl) zirconium hydride chloride,
And the like. In the above examples, disubstituted cyclopentadienyl ring includes 1,2- and 1,3-substituted, and tri-substituted includes 1,2,3- and 1,2,4-substituted. Including. In the present invention, a transition metal compound obtained by replacing zirconium metal with titanium metal or hafnium metal in the zirconium compound as described above can be used.

Among these transition metal compounds represented by the general formula [I],
Bis (n-propylcyclopentadienyl) zirconium dichloride,
Bis (n-butylcyclopentadienyl) zirconium dichloride,
Bis (1-methyl-3-n-propylcyclopentadienyl) zirconium dichloride, bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dichloride,
Is particularly preferred.

Next, (b) the organic aluminum oxy compound will be described.
The organoaluminum oxy compound (b) (hereinafter sometimes referred to as "component (b)") used in the present invention may be a conventionally known benzene-soluble aluminoxane. It may be a benzene-insoluble organic aluminum oxy compound as disclosed in Japanese Patent No. 276807.

The aluminoxane as described above can be produced, for example, by the following method.
(1) Compounds containing water of adsorption or salts containing water of crystallization, for example, magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate, cerous chloride hydrate, etc. A method of adding an organoaluminum compound such as trialkylaluminum to a suspension of a hydrocarbon medium of Example 1 and reacting the suspension to recover a hydrocarbon solution.

{Circle around (2)} A method in which water, ice or steam is allowed to act directly on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran to recover as a hydrocarbon solution.

(3) A method of reacting an organoaluminum compound such as trialkylaluminum with an organotin oxide such as dimethyltin oxide or dibutyltin oxide in a medium such as decane, benzene or toluene.

The aluminoxane may contain a small amount of an organometallic component. Alternatively, the solvent or unreacted organoaluminum compound may be removed from the recovered aluminoxane solution by distillation, and then redissolved in the solvent.

Specific examples of the organoaluminum compound used in producing aluminoxane include trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, trin-butylaluminum, triisobutylaluminum, trisec-butylaluminum, trialkylaluminums such as tert-butylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum;
Tricycloalkyl aluminums such as tricyclohexyl aluminum, tricyclooctyl aluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide and diisobutylaluminum chloride;
Dialkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride;
Dialkyl aluminum alkoxides such as dimethyl aluminum methoxide and diethyl aluminum ethoxide;
Examples include dialkylaluminum aryloxides such as diethylaluminum phenoxide.

Of these, trialkylaluminum and trialkylaluminum are particularly preferred.
Further, as this organoaluminum compound, a compound represented by the general formula (i-C ₄ H ₉ ) _x Al _y (C ₅ H ₁₀ ) _z
(X, y, and z are positive numbers and z ≧ 2x)
Can also be used.

The above-mentioned organoaluminum compounds are used alone or in combination.
Solvents used in the production of aluminoxane include aromatic hydrocarbons such as benzene, toluene, xylene, cumene and cymene, and aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, hexadecane and octadecane. Hydrogen, alicyclic hydrocarbons such as cyclopentane, cyclohexane, cyclooctane and methylcyclopentane; petroleum fractions such as gasoline, kerosene and light oil; and halogens of the above aromatic hydrocarbons, aliphatic hydrocarbons and alicyclic hydrocarbons Hydrocarbon solvents such as chlorides, bromides and the like. In addition, ethers such as ethyl ether and tetrahydrofuran can also be used. Among these solvents, aromatic hydrocarbons are particularly preferred.

In the benzene-insoluble organoaluminum oxy compound used in the present invention, the Al component soluble in benzene at 60 ° C. is 10% or less, preferably 5% or less, particularly preferably 2% or less in terms of Al atom. On the other hand, it is insoluble or hardly soluble.

The solubility of such an organoaluminum oxy compound in benzene is 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 adding a jacket. Using a G-5 glass filter, filtration was performed while heating at 60 ° C., and the solid part separated on the filter was washed four times with 50 ml of benzene at 60 ° C., and then the total amount of Al atoms present in the total filtrate was measured. It is determined by measuring the abundance (x mmol) (x%).

The carrier (c) (hereinafter sometimes referred to as “component (c)”) used in the present invention is an inorganic or organic compound and has a particle size of 10 to 300 μm, preferably 20 to 200 μm. Solids in the form of particles or fine particles are used. Among these, a porous oxide is preferable as the inorganic carrier, and specifically, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , C ₂
aO, ZnO, BaO, ThO _{2 and the} like or a mixture thereof, for example, SiO ₂ —MgO, Si
Examples thereof include O ₂ -Al ₂ O ₃ , SiO ₂ -TiO ₂ , SiO ₂ -V ₂ O ₅ , SiO ₂ -Cr ₂ O ₃ , and SiO ₂ -TiO ₂ -MgO. Among them, those containing at least one component selected from the group consisting of SiO ₂ and Al ₂ O ₃ as a main component are preferable.

In addition, a small amount of Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , Na ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , BaSO ₄ , KNO ₃ , Mg (NO ₃ ) ₂ , carbonates such as Al (NO ₃ ) ₃ , Na ₂ O, K ₂ O and Li ₂ O, sulfates, nitrates and oxides may be contained.

Such a carrier (c) has different properties depending on its type and production method, but the carrier preferably used in the present invention has a specific surface area of 50 to 1000 m ² / g, preferably 100 to 700 m ² / g, It is desirable that the volume is 0.3 to 2.5 cm ² / g. The carrier is used by firing at 100 to 1000 ° C, preferably 150 to 700 ° C, if necessary.

Further, examples of the carrier (c) that can be used in the present invention include a granular or fine solid of an organic compound having a particle size of 10 to 300 μm. These organic compounds include those having 2 to 1 carbon atoms such as ethylene, propylene, 1-butene and 4-methyl-1-pentene.
(Co) polymers formed mainly with α-olefin No. 4 or polymers or copolymers formed mainly with vinylcyclohexane or styrene.

The catalyst used in the present invention comprises (a) a transition metal compound of Group IV of the periodic system containing a ligand having a specific cyclopentadienyl skeleton, (b) an organoaluminum oxy compound, and (c) a carrier. However, if necessary, (d) an organoaluminum compound may be used.

As the (d) organoaluminum compound used as necessary (hereinafter sometimes referred to as “component (d)”), for example, an organoaluminum compound represented by the following general formula [II] may be exemplified. it can.

R ¹ _n AlX _3-n ... [II]
(In the formula [II], R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom or a hydrogen atom, and n is 1 to 3.)
In the above general formula [II], R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, for example, an alkyl group, a cycloalkyl group or an aryl group. Specifically, methyl, ethyl, n-propyl Group, isopropyl group, isobutyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.

As such an organoaluminum compound (d), specifically, the following compounds are used.
Trialkylaluminums such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum;
Alkenyl aluminum, such as isoprenyl aluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride and dimethylaluminum bromide;
Alkylaluminum sesquihalides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride, ethylaluminum sesquibromide;
Alkylaluminum dihalides such as methylaluminum dichloride, ethylaluminum dichloride, isopropylaluminum dichloride, ethylaluminum dibromide;
Alkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride;

Further, as the organoaluminum compound (d), a compound represented by the following general formula [III] can also be used.

R ¹ _n AlY _3-n ... [III]
(Wherein [III], R ¹ is as defined above, Y is -OR ² group, -OSiR ³ ₃ group, -OAlR ⁴ ₂ group, -NR ⁵ ₂ group, -SiR ⁶ ₃ group or -N ( R ⁷⁾ is AlR ⁸ ₂ group, n is ^{1~2, R 2, R 3,} R 4 and R ⁸ are a methyl group, an ethyl group, an isopropyl group, an isobutyl group, a cyclohexyl group, a phenyl group , R ⁵ are a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a trimethylsilyl group, and the like, and R ⁶ and R ⁷ are a methyl group, an ethyl group, and the like.)
As such an organoaluminum compound, specifically, the following compounds are used.

(1) A compound represented by R ¹ _n Al (OR ² ) _3-n , for example, dimethylaluminum methoxide, diethylaluminum ethoxide, diisobutylaluminum methoxide, etc.
(2) Compound represented by 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 ) etc .;
_{^{(3) R 1 n Al (}} OAlR 4 2) a compound represented by _3-n, e.g., Et ₂ AlOAlEt _2, such as _{(iso-Bu) 2 AlOAl (} iso-Bu) 2;
_{^{(4) R 1 n Al (}} NR 5 2) a compound represented by _3-n, e.g., _{Me 2 AlNEt 2, Et 2 AlNHMe} , Me 2 AlNHEt, Et 2 AlN (SiMe 3) 2, (iso-
Bu) ₂ AlN (SiMe ₃ ) _{2 and the} like;
_{^{(5) R 1 n Al (}} SiR 6 3) a compound represented by _3-n, e.g., (iso-Bu) such as ₂ AlSi Me _3;

Among the above-mentioned general formula [II] and an organoaluminum compound represented by [III], the general formula ^{_{R 1 3 Al, R 1 n}} Al (OR 2) 3-n, R 1 n Al (OAlR 4 2) 3 A compound represented by _-n is preferred, and a compound wherein R is an isoalkyl group and n = 2 is particularly preferred.

In the present invention, when producing the ethylene / α-olefin copolymer [A], the above-mentioned components (a), (b) and (c) are brought into contact with component (d) as necessary. The catalyst prepared in this way is used. The order of contacting the components (a) to (d) at this time is arbitrarily selected, but preferably the components (c) and (b) are mixed and contacted, and then the component (a) is mixed and contacted. Further, if necessary, the component (d) is mixed and brought into contact.

The contact of the above components (a) to (d) can be performed in an inert hydrocarbon solvent, and specific examples of the inert hydrocarbon medium used for preparing the catalyst include propane, butane, pentane and hexane. , Heptane, octane, decane, dodecane, kerosene, etc .; aliphatic hydrocarbons, such as cyclopentane, cyclohexane, methylcyclopentane; aromatic hydrocarbons, such as benzene, toluene, xylene; ethylene chloride, chlorobenzene And halogenated hydrocarbons such as dichloromethane, and mixtures thereof.

In mixing and contacting the component (a), the component (b), the component (c) and, if necessary, the component (d), the component (a) is usually 5 × 10 ^{−6 to} 5 × per 1 g of the component (c). It is used in an amount of 10 ^-4 mol, preferably 10 ^-5 to 2 × 10 ^-4 mol, and the concentration of component (a) is about 10 ^-4 to 2 × 10 ^-2 mol / l, preferably 2 × 10 ^-4 mol. The range is from ^-4 to 10 ^-2 mol / l. The atomic ratio (Al / transition metal) of aluminum of the component (b) to the transition metal in the component (a) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) of the component (d) and the aluminum atom (Al-b) of the component (b) used as required is usually from 0.02 to 3, preferably in the range of 0.05 to 1.5. Component (a), component (
The mixing temperature for mixing and contacting b), component (c) and, if necessary, component (d) is usually -50 to 150 ° C, preferably -20 to 120 ° C, and the contact time is 1 minute to 50 ° C. Time, preferably 10 minutes to 25 hours.

The ethylene / α-olefin copolymer [A] polymerization catalyst obtained as described above has a transition metal atom derived from the component (a) in an amount of 5 × 10 ^{−6 to} 5 × 10 ⁶ per g of the component (c). ^-4 gram atoms, preferably 10 ^-5 to 2 × 10 ^-4 gram atoms, and the amount of aluminum atoms derived from component (b) and component (d) per gram of component (c) is 10 ^-3 to It is desirable that the carrier be carried in an amount of 5 × 10 ⁻² gram atoms, preferably 2 × 10 ⁻³ to 2 × 10 ⁻² gram atoms.

The catalyst used in the production of the ethylene / α-olefin copolymer [A] is prepared by using the above components (a), (b), (c) and, if necessary, component (d). It may be a prepolymerized catalyst obtained by prepolymerizing an olefin. The prepolymerization is carried out by introducing an olefin into an inert hydrocarbon solvent in the presence of the components (a), (b), (c) and, if necessary, the component (d) as described above. Can be.

As the olefin used in the prepolymerization, ethylene and an α-olefin having 3 to 20 carbon atoms, for example, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene , 1-decene, 1-dodecene, 1-tetradecene, and the like. Of these, ethylene used in the polymerization or a combination of ethylene and an α-olefin is particularly preferred.

In the prepolymerization, the component (a) is used in an amount of usually 10 ⁻⁶ to 2 × 10 ⁻² mol / l, preferably 5 × 10 ⁻⁵ to 10 ⁻² mol / l. b) is generally used in an amount of 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ mol, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ mol per 1 g of the component (c). The atomic ratio (Al / transition metal) of aluminum of the component (b) to the transition metal in the component (a) is usually 10 to 500, preferably 20 to 200. The atomic ratio (Al-d / Al-b) of the aluminum atom (Al-d) of the component (d) and the aluminum atom (Al-b) of the component (b) used as required is usually from 0.02 to 3, preferably in the range of 0.05 to 1.5. The prepolymerization temperature is -20 to 80 ° C, preferably 0 to 60 ° C, and the prepolymerization time is 0.5.
It is about 100 hours, preferably about 1 to 50 hours.

The prepolymerization catalyst is prepared, for example, as follows. That is, the carrier (component (c)) is suspended with an inert hydrocarbon. Next, an organic aluminum oxy compound (component (b)) is added to the suspension and reacted for a predetermined time. Thereafter, the supernatant is removed and the solid component obtained is resuspended with an inert hydrocarbon. After adding a transition metal compound (component (a)) into the system and reacting for a predetermined time, the supernatant is removed to obtain a solid catalyst component. Subsequently, the solid catalyst component obtained above is added to an inert hydrocarbon containing an organoaluminum compound (component (d)), and an olefin is introduced therein to obtain a prepolymerized catalyst.
The amount of the olefin polymer produced by the prepolymerization is preferably 0.1 to 500 g, preferably 0.2 to 300 g, more preferably 0.5 to 200 g per 1 g of the carrier (c). In the prepolymerized catalyst, the component (a) is about 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ g atoms, preferably 10 ⁻⁵ to 2 × 10 ⁻⁴ g, as a transition metal atom per 1 g of the support (c). The aluminum atoms (Al) derived from the components (b) and (d) are supported in the amount of atoms and have a molar ratio (Al / M) of 5 to the transition metal atoms (M) derived from the component (a). It is desirably carried in an amount of from 200 to 200, preferably from 10 to 150.

The prepolymerization can be carried out either in a batch system or a continuous system, and can be carried out under reduced pressure, normal pressure or increased pressure. In the prepolymerization, the intrinsic viscosity [η] measured in decalin at least at 135 ° C. is in the range of 0.2 to 7 dl / g in the presence of hydrogen.
It is desirable to produce a prepolymer of preferably 0.5-5 dl / g.

The ethylene / α-olefin copolymer [A] used in the present invention is obtained by adding ethylene and an α-olefin having 3 to 20 carbon atoms, for example, propylene, 1-butene, -Pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene. Can be

で は In the present invention, the copolymerization of ethylene and α-olefin is carried out in a gas phase or in a slurry liquid phase. In slurry polymerization, an inert hydrocarbon may be used as a solvent, or olefin itself may be used as a solvent.

As the inert hydrocarbon solvent used in the slurry polymerization, specifically, butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, aliphatic hydrocarbons such as octadecane; cyclopentane, methylcyclopentane, cyclohexane, Alicyclic hydrocarbons such as cyclooctane; aromatic hydrocarbons such as benzene, toluene and xylene; and petroleum fractions such as gasoline, kerosene and light oil. Among these inert hydrocarbon media, aliphatic hydrocarbons, alicyclic hydrocarbons, petroleum fractions and the like are preferred.

When the slurry polymerization method or the gas phase polymerization method is used, the above-mentioned catalyst is used in a concentration of transition metal atoms in the polymerization reaction system of usually 10 ^-8 to 10 ^-3 gram atoms / liter, preferably 10 ^-10 g atoms / liter. ^Preferably, it is used in an amount of ^-7 to 10 ^-4 gram atoms / liter.

In addition, the same organic aluminum oxy compound and / or organic aluminum compound (d) as the component (b) may be added during the main polymerization. At this time, the atomic ratio (Al / M) between the aluminum atom (Al) derived from the organic aluminum oxy compound and the organic aluminum compound and the transition metal atom (M) derived from the transition metal compound (a) is 5 to 300. , Preferably from 10 to 200, more preferably from 15 to 150.

In the present invention, when performing the slurry polymerization method, the polymerization temperature is usually in the range of −50 to 100 ° C., preferably 0 to 90 ° C., and when performing the gas phase polymerization method, the polymerization temperature is , Usually in the range of 0 to 120 ° C, preferably 20 to 100 ° C.

The polymerization pressure is usually from atmospheric pressure 100 kg / cm ^2, and preferably a pressurized condition of to 50 kg / cm ^2, the polymerization is a batch, semi-continuous, be carried out by any of the methods of continuous it can.

Further, the polymerization can be performed in two or more stages having different reaction conditions.
[High-pressure radical method low-density polyethylene [B]]
Next, the high pressure radical method low density polyethylene [B] used in the present invention will be specifically described.

The high-pressure radical method low-density polyethylene [B] is a highly branched polyethylene having a long-chain branch and produced by so-called high-pressure radical polymerization, and has a length of 19 in accordance with ASTM D1238-65T.
The MFR measured under the conditions of 0 ° C. and a load of 2.16 kg is in the range of 0.1 to 50 g / 10 min, preferably in the range of 0.2 to 10 g / 10 min. More preferably, it is within a range of 分 の 8 g / 10 minutes.

The high-pressure radical method low-density polyethylene according to the present invention has a molecular weight distribution index (Mw / Mn; Mw: weight average molecular weight, Mn: number average molecular weight) measured by gel permeation chromatography (GPC). Melt flow rate (MFR) is 7.5 × log (MFR) −1.2 ≦ Mw / Mn ≦ 7.5 × log (MFR) +12.5
Preferably, 7.5 × log (MFR) −0.5 ≦ Mw / Mn ≦ 7.5 × log (MFR) +12.0
More preferably, 7.5 × log (MFR) ≦ Mw / Mn ≦ 7.5 × log (MFR) +12.0
Satisfies the relationship indicated by.

In addition, the molecular weight distribution (Mw / Mn) of the high-pressure method low-density polyethylene was measured as follows using GPC-150C manufactured by Millipore.
The separation column was TSK GNH HT, the column size was 72 mm in diameter and 600 mm in length, the column temperature was 140 ° C., and the mobile phase was o-dichlorobenzene (Wako Pure Chemical Industries) and BHT (BOT) as an antioxidant. (Takeda Pharmaceutical) 0.025% by weight was moved at 1.0 ml / min, the sample concentration was 0.1% by weight, the sample injection amount was 500 microliters, and a differential refractometer was used as a detector. As for the standard polystyrene, those having a molecular weight of Mw <1000 and Mw> 4 × 10 ⁶ were manufactured by Tosoh Corporation, and those having a molecular weight of 1000 <Mw <4 × 10 ⁶ were manufactured by Pressure Chemical Company.

The high-pressure radical method low-density polyethylene according to the present invention has a density (d) of 0.910 to 0.910.
Desirably, it is in the range of 0.930 g / cm ³ .
The density is measured by a density gradient tube after heat treating a strand obtained at a melt flow rate (MFR) measurement at 190 ° C. under a load of 2.16 kg at 120 ° C. for 1 hour and cooling it to room temperature over 1 hour.

The high-pressure radical method low-density polyethylene [B] according to the present invention has an inner diameter (D) of 2.0 mm at 190 ° C. using a swell ratio indicating the degree of long-chain branching, that is, a capillary flow property tester. It is desirable that the ratio (Ds / D) of the diameter (Ds) of the strand extruded from a 15 mm long nozzle at an extrusion speed of 10 mm / min to the nozzle inner diameter D (Ds / D) is 1.3 or more.

The high-pressure radical method low-density polyethylene [B] used in the present invention is compatible with other α-olefins, vinyl acetate, acrylic acid esters and other polymerizable monomers as long as the object of the present invention is not impaired. May be used.

[Ethylene copolymer composition]
The ethylene-based copolymer composition of the present invention comprises the ethylene / α-olefin copolymer [A] and the high-pressure radical method low-density polyethylene [B], and comprises the ethylene / α-olefin copolymer [A]. And the weight ratio ([A]: [B]) of the high-pressure radical method low-density polyethylene [B] is in the range of 99: 1 to 60:40, but is in the range of 98: 2 to 70:30. Is preferable, and it is more preferable that it is in the range of 98: 2 to 80:20.

If the amount of the high-pressure radical method low-density polyethylene [B] is less than the above range, the effect of modifying the transparency and the melt tension may be insufficient. If the amount is more than the above range, the tensile strength and the stress crack resistance may be insufficient. Etc. may be greatly reduced.

The ethylene-based copolymer composition of the present invention, within a range that does not impair the purpose of the present invention, a weather-resistant stabilizer, a heat-resistant stabilizer, an antistatic agent, an anti-slip agent, an anti-blocking agent, an anti-fogging agent, a lubricant, Additives such as pigments, dyes, nucleating agents, plasticizers, antioxidants, hydrochloric acid absorbents, antioxidants and the like may be added as necessary.

The ethylene copolymer composition of the present invention can be produced by using a known method, and for example, can be produced by the following method.
(1) A method of mechanically blending an ethylene / α-olefin copolymer [A], a high-pressure radical method low-density polyethylene [B], and optionally other components using an extruder, a kneader, or the like. .

(2) An ethylene / α-olefin copolymer [A], a high-pressure radical method low-density polyethylene [B], and other components to be added as required are mixed with a suitable good solvent (for example, hexane, heptane, decane, cyclohexane, A solvent such as benzene, toluene and xylene) and then removing the solvent.

(3) After preparing a solution obtained by separately dissolving the ethylene / α-olefin copolymer [A], the high-pressure radical method low-density polyethylene [B], and other components to be added as needed in a suitable good solvent. A method of mixing and then removing the solvent.
(4) A method in which the above methods (1) to (3) are combined.

The ethylene copolymer composition of the present invention can be obtained by processing by ordinary air-cooled inflation molding, air-cooled two-stage cooling inflation molding, high-speed inflation molding, T-die film molding, water-cooled inflation molding, or the like. it can. The film thus formed is excellent in transparency and mechanical strength, and has heat sealing property, hot tack property, heat resistance, good blocking property and the like, which are the characteristics of ordinary LLDPE. Further, since the composition distribution of the ethylene / α-olefin copolymer [A] is extremely narrow, there is no stickiness on the film surface. Further, since the stress is low even in a high shearing range, high-speed extrusion is possible, and power consumption is reduced, which is economically advantageous.

Films obtained by processing the ethylene-based copolymer composition of the present invention include standard bags, heavy bags, wrap films, laminating webs, sugar bags, oil packaging bags, water packaging bags, food packaging and the like. Suitable for various packaging films, infusion bags, agricultural materials and the like. Also, it can be used as a multilayer film by being bonded to a substrate such as nylon or polyester. Further, it can be used for blow-infusion bags, blow bottles, extrusion molded tubes, pipes, tear-off caps, injection molded products such as daily necessities, fibers, and large molded products formed by rotational molding.

[Example]
Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

In the present invention, the physical properties of the ethylene copolymer composition are evaluated as follows. [Current Index (FI)]
It is defined as the shear rate at which the shear stress at 190 ° C. reaches 2.4 × 10 ⁶ dyne / cm ² . The flow index (FI) is determined by extruding the resin from the capillary while changing the shear rate, and measuring the stress at that time. That is, using the same sample as in the MT measurement, using a capillary flow characteristic tester manufactured by Toyo Seiki Seisakusho, at a resin temperature of 190 ° C. and a shear stress in the range of 5 × 10 ^{4 to} 3 × 10 ⁶ dyne / cm ² . Measured.

The nozzle diameter is changed as follows according to the MFR (g / 10 minutes) of the resin to be measured.

0.5 mm when MFR> 20
1.0mm when 20 ≧ MFR> 3
2.0mm when 3 ≧ MFR> 0.8
3.0mm when 0.8 ≧ MFR
[Haze (cloudiness)]
It was measured according to ASTM-D-1003-61.

[Gloss (gloss)]
It was measured according to JIS Z8741.

[Film Impact]
It was measured by a pendulum-type film impact tester (film impact tester) manufactured by Toyo Seiki Seisaku-sho, Ltd.

[Blocking power]
An inflation film cut into a size of 7 (width) × 20 cm is sandwiched between type papers, and further sandwiched between glass plates, and a load of 10 kg is applied for 24 hours in a 50 ° C. air bath. The film was attached to an open jig and pulled apart at 200 mm / min. The load at this time was defined as Ag, and the blocking force F (g / cm) was represented by F = A / test specimen width. The smaller the value of F, the more difficult the blocking is, that is, the higher the blocking resistance is.

[Production Example 1]
Production of ethylene / α-olefin copolymer [A] [Preparation of catalyst]
6.3 kg of silica dried at 250 ° C. for 10 hours was suspended in 100 liter of toluene, and then cooled to 0 ° C. Thereafter, 41 l of a toluene solution of methylaluminoxane (Al = 0.96 mol / l) was added dropwise over 1 hour. At this time, the temperature in the system was set to 0 ° C.
Kept. Subsequently, the reaction was carried out at 0 ° C. for 60 minutes, and then the temperature was raised to 95 ° C. over 1.5 hours.
The reaction was carried out at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method. The solid component thus obtained was washed twice with toluene and then resuspended in 125 liters of toluene. Into this system, 15 liters of a toluene solution of bis (n-butylcyclopentadienyl) zirconium dichloride (Zr = 42.7 mmol / l) was dropped at 30 ° C. for 30 minutes, and further reacted at 30 ° C. for 2 hours. Was. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst containing 6.2 mg of zirconium per gram.

[Preparation of prepolymerized catalyst]
8.5 kg of the solid catalyst obtained above was added to 300 liters of hexane containing 14 mol of triisobutylaluminum, and prepolymerization of ethylene was carried out at 35 ° C. for 7 hours to obtain 3 g of polyethylene per 1 g of solid catalyst. A polymerized prepolymerized catalyst was obtained.

[Consolidation]
Using a continuous fluidized-bed gas-phase polymerization apparatus, ethylene and 1-hexene were copolymerized at a total pressure of 18 kg / cm ² -G and a polymerization temperature of 80 ° C. The prepolymerized catalyst prepared above was continuously supplied at a rate of 0.15 mmol / h in terms of zirconium atoms and triisobutylaluminum at a rate of 10 mmol / h, and ethylene and 1- to maintain a constant gas composition during the polymerization. Hexene, hydrogen, and nitrogen were continuously supplied (gas composition; 1-hexene / ethylene = 0.020, hydrogen / ethylene = 6.6 × 10 ⁻⁴ , ethylene concentration = 16%).

The yield of the obtained ethylene / α-olefin copolymer (A-1) was 5.0 kg / hr, the density was 0.923 g / cm ³ , and the melt flow rate (MFR) was 1.1 g / hr. 1
0 minute, the maximum peak of the melting point in DSC was 116.8 ° C., the melt tension (MT) was 1.5 g, the decane-soluble portion at 23 ° C. was 0.02 parts by weight, and the unsaturated bond was Was 0.09 per 1000 carbon atoms and 0.16 per polymer molecule, and the B value indicating the distribution of α-olefins in the copolymer chain was 1.02. .

[Preparation of composition]
Mixing ratio of ethylene / α-olefin copolymer (A-1) obtained in Production Example 1 and high-pressure radical method low-density polyethylene (B-2) shown in Table 2 (A-1 / B-2) 90 / 10 and dry blended with 100 parts by weight of resin, and tri (2,4-di-t) as a secondary antioxidant.
-Butylphenyl) phosphate and 0.05 parts by weight of n-octadecyl-3- (4'-hydroxy-3 ', 5'-di-t-butylphenyl) propionate as a heat stabilizer. And 0.05% by weight of calcium stearate as a hydrochloric acid absorbent. Thereafter, using a conical tapered twin-screw extruder manufactured by Haake Corporation, the mixture was kneaded at a set temperature of 180 ° C. to obtain an ethylene copolymer composition.

[Film processing]
Using the ethylene copolymer composition obtained above, 20 mmφ · L / D = 26 single screw extruder, 25 mmφ die, lip width 0.7 mm, air flow rate = 90 l / min using single slit air ring, extrusion A film having an amount of 9 g / min, a blow ratio of 1.8, a take-up speed of 2.4 m / min, a processing temperature of 200 ° C., and a thickness of 30 μm was blown. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

Example 1 was the same as Example 1 except that the mixing ratio (A-1 / B-2) of the ethylene / α-olefin copolymer (A-1) and the high-pressure radical method low-density polyethylene (B-2) was 75/25. An ethylene-based copolymer composition was prepared in the same manner, and a film having a thickness of 30 μm was formed in the same manner as in Example 1 using this ethylene-based copolymer composition. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

An ethylene copolymer was obtained in the same manner as in Example 1 except that the high-pressure radical method low-density polyethylene (B-1) shown in Table 2 was used instead of the high-pressure radical method low-density polyethylene (B-2). A composition was prepared, and a film having a thickness of 30 μm was formed in the same manner as in Example 1 using this ethylene-based copolymer composition. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

[Reference Example 1]
Using the ethylene / α-olefin copolymer (A-1) obtained in Production Example 1, a film having a thickness of 30 μm was formed in the same manner as in Example 1. Table 3 shows the melt properties and film properties.

[Comparative Example 1]
[Production of ethylene / α-olefin copolymer (A-7)]
In Production Example 1, a comonomer was prepared by using a titanium-based catalyst component described in JP-B-63-54289 instead of bis (n-butylcyclopentadienyl) zirconium dichloride, and triethylaluminum instead of methylaluminoxane. An ethylene / α-olefin copolymer (A-7) was produced in the same manner as in Example 1 except that the content was adjusted as shown in Table 1. Table 1 shows the physical properties of the obtained ethylene / α-olefin copolymer (A-7).

[Preparation of composition]
Using the ethylene / α-olefin copolymer (A-7) obtained as described above and the high-pressure radical method low-density polyethylene (B-1) shown in Table 2, an ethylene-based copolymer was obtained in the same manner as in Example 1. A copolymer composition was prepared.

[Film processing]
Using the ethylene copolymer composition prepared above, a film having a thickness of 30 μm was formed in the same manner as in Example 1. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

As shown in Table 3, the obtained film was inferior in film impact, had a wide composition distribution, and had many solid components, and thus had poor blocking resistance. Further, when comparing Example 3 and Comparative Example 1 using ethylene / α-olefin copolymers having the same comonomer type and the same MFR and density, Example 3 has a large effect of improving the haze.

[Comparative Example 2]
Using the ethylene / α-olefin copolymer (A-7) obtained in Comparative Example 1, a film having a thickness of 30 μm was formed in the same manner as in Example 1. Table 3 shows the melting properties and film properties.

[Production Examples 2 to 4]
Ethylene / α-olefin copolymers (A-2, A-3, A-4) were produced in the same manner as in Production Example 1, except that the comonomer type and comonomer content were changed as shown in Table 1. Table 1 shows the physical properties of the obtained ethylene / α-olefin copolymers (A-2, A-3, A-4).

[Examples 4 to 6]
Except that the ethylene / α-olefin copolymers (A-2, A-3, A-4) obtained in Production Examples 2 to 4 and the high-pressure radical method low-density polyethylene (B-1) shown in Table 2 were used. In the same manner as in Example 1, an ethylene-based copolymer composition was prepared, and a film having a thickness of 30 μm was formed using this ethylene-based copolymer composition in the same manner as in Example 1. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

[Reference Examples 2 to 4]
Using the ethylene / α-olefin copolymers (A-2, A-3, A-4) obtained in Production Examples 2 to 4, a 30-μm-thick film was formed in the same manner as in Example 1. Table 3 shows the melt properties and film properties.

[Production Examples 5 and 6]
In Production Example 1, bis (1-methyl-3-n-butylcyclopentadienyl) zirconium dichloride was used in place of bis (n-butylcyclopentadienyl) zirconium dichloride, and the comonomer composition was as shown in Table 1. An ethylene / α-olefin copolymer (A-5, A-6) was produced in the same manner as in Production Example 1 except for the above. Table 1 shows the physical properties of the obtained ethylene / α-olefin copolymer (A-5, A-6).

[Examples 7 and 8]
Example 1 except that the ethylene / α-olefin copolymers (A-5, A-6) obtained in Production Examples 5 and 6 and the high-pressure radical method low-density polyethylene (B-1) shown in Table 2 were used. An ethylene-based copolymer composition was prepared in the same manner as described above, and a film having a thickness of 30 μm was formed using this ethylene-based copolymer composition in the same manner as in Example 1. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.

[Reference Examples 5 and 6]
Using the ethylene / α-olefin copolymers (A-5, A-6) obtained in Production Examples 5 and 6, a film having a thickness of 30 μm was formed in the same manner as in Example 1. Table 3 shows the melt properties and film properties.

[Comparative Example 3]
Using the ethylene / α-olefin copolymer (A-1) obtained in Production Example 1 and the high-pressure radical method low-density polyethylene (B-3) shown in Table 2, an ethylene copolymer was obtained in the same manner as in Example 1. A composition was prepared, and a film having a thickness of 30 μm was formed in the same manner as in Example 1 using this ethylene-based copolymer composition. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.
As is clear from Comparative Example 3 and Reference Example 1, even when the ethylene / α-olefin copolymer is blended with the high-pressure radical method low-density polyethylene used in Comparative Example 3, the transparency of the film is little improved.

[Comparative Example 4]
Using the ethylene / α-olefin copolymer (A-1) obtained in Production Example 1 and the high-pressure radical method low-density polyethylene (B-4) shown in Table 2, an ethylene copolymer was obtained in the same manner as in Example 1. A composition was prepared, and a film having a thickness of 30 μm was formed in the same manner as in Example 1 using this ethylene-based copolymer composition. Table 3 shows the melt properties and film properties of the ethylene copolymer composition.
As is clear from Comparative Example 4 and Reference Example 1, even when the ethylene / α-olefin copolymer is blended with the high-pressure radical method low-density polyethylene used in Comparative Example 4, the melt tension hardly increases. Also, the transparency of the film does not improve much.
As is clear from the above Examples and Reference Examples, blending a specific high-pressure radical method low-density polyethylene with an ethylene / α-olefin copolymer improves melt tension and haze (transparency). Further, the ethylene copolymer composition according to the present invention has excellent blocking resistance.

Claims (1)

[A] a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms,
(I) the density (d) is in the range of 0.880 to 0.960 g / cm ³ ;
(Ii) a melt flow rate (MFR) at 190 ° C. and a load of 2.16 kg is in a range of 0.01 to 200 g / 10 minutes;
(Iii) The maximum peak (T (° C.)) of the melting point in DSC and the density (d) are:
T <400 × d-250
Satisfy the relationship indicated by
(Iv) The melt tension (MT (g)) at 190 ° C. and the melt flow rate (MFR)
MT ≦ 2.2 × MFR ^-0.84
Satisfy the relationship indicated by
(V) The decane-soluble portion (W (% by weight)) at 23 ° C. and the density (d) are:
When MFR ≦ 10 g / 10 minutes,
W <80 × exp (−100 (d−0.88)) + 0.1
When MFR> 10g / 10min,
W <80 × (MFR-9) ^0.26 × exp (−100 (d−0.88)) + 0.1
An ethylene / α-olefin copolymer satisfying the relationship represented by:
[B] low-density polyethylene obtained by a high-pressure radical method,
(I) the melt flow rate (MFR) is in the range of 0.1 to 50 g / 10 minutes,
(Ii) The molecular weight distribution (Mw / Mn: Mw = weight average molecular weight, Mn = number average molecular weight) measured by GPC and the melt flow rate (MFR) are:
7.5 × log (MFR) −1.2 ≦ Mw / Mn ≦ 7.5 × log (MFR) +12.5
And a weight ratio of the ethylene / α-olefin copolymer [A] and the high-pressure radical method low-density polyethylene [B] ([A]: [B] ]) Is in the range of 99: 1 to 60:40.