JPH10110068A - Polyethylene resin composition for film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition which can give polyethylene films having good opening nature, transparency and blocking resistance by the water-cooled inflation process by mixing a specified linear ethylene/α-olefin copolymer with a high-density polyethylene. SOLUTION: This composition comprises 90-95 pts.wt. linear ethylene/3-20C α-olefin copolymer and 5-10 pts.wt. high-density polyethylene (B) comprising an ethylene homopolymer or a ethylene/3-20C α-olefin copolymer. Component A has an ethylene content of 50 to below 100wt.%, a density of 0.905-0.935g/cm<3> , an MFR of 0.1-30g/10min, a molecular weight distribution Mw/Mn of 1.5-2.5 and a content of n-decane extractibles (at ordinary temperature) of 2wt.% or below. Component B has an ethylene content of 50-100wt.%, a density of 0.945-0.975g/cm<3> , an MFR of 0.5-10g/10min and a molecular weight distribution Mw/Mn of 2.5-5. A film, especially a water-cooled inflation film, made from this composition has high mechanical strengths, good suitability for production and suited for packaging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene resin composition for a film which is suitable mainly for single film packaging.

[0002]

BACKGROUND OF THE INVENTION In recent years, plastic films (sheets) such as polypropylene have been widely used as plastic materials for packaging.

[0003] Conventional polypropylene films for packaging are:
Generally, it is manufactured by a so-called T-die method. This T
The performance of the film obtained by the die method is superior to the blown film. However, this T
The die method has a problem that the equipment cost is high.

Accordingly, the inventors of the present invention have proposed a linear low-density polyethylene (L-LDP) by an air-cooled inflation method.
The production of a polyethylene film consisting of E) was studied.
However, the cooling efficiency is low in the air cooling method, and the obtained polyethylene film has a difficulty in balancing transparency and blocking resistance.

Accordingly, the inventors of the present application have made intensive studies to further solve this problem and have found that certain linear ethylene
When a film was produced from a polyethylene resin composition in which an α-olefin copolymer and a specific high-density polyethylene were blended in a specific ratio, polyethylene having excellent opening properties, and an excellent balance between transparency and blocking resistance They found that a film could be obtained and completed the present invention.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyethylene resin composition for a film capable of preparing a polyethylene film having an excellent balance between transparency and blocking resistance.

[0007]

SUMMARY OF THE INVENTION The polyethylene resin composition for a film according to the present invention comprises: (A) a linear ethylene / α-olefin copolymer obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms. 90 to 95 parts by weight of a polymer; and (B) 5 to 10 parts by weight of a high-density polyethylene comprising ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms [component (A) and (B)
Is 100 parts by weight], and the linear ethylene / α-olefin copolymer (A) has (i) an ethylene content of 50% by weight or more and 100% by weight. % And (ii) the density is 0.905 to 0.9.
(Iii) Melt flow rate (MFR; ASTM D 1238, 190 ° C., load 2.16 kg) is 0.3 g / cm ³ .
(Iv) the molecular weight distribution (Mw / Mn) measured by GPC is 1.5 to 2.5.
(V) the normal-temperature n-decane extraction amount is 2.0% by weight or less, and the high-density polyethylene (B) has (i) an ethylene content in a range of 50 to 100% by weight; ii) the density is in the range of 0.945 to 0.975 g / cm ³ ,
(iii) Melt flow rate (MFR; ASTM D 1238, 190
° C, load 2.16 kg) is in the range of 0.5 to 10.0 g / 10 minutes, and (iv) molecular weight distribution (Mw) measured by GPC.
/ Mn) is in the range of 2.5 to 5.0.

In the composition, the following high-pressure low-density polyethylene (C) is added to 100 parts by weight of the total amount of the linear ethylene / α-olefin copolymer (A) and the high-density polyethylene (B). On the other hand, 5 to 20 parts by weight can be contained.

The high-pressure low-density polyethylene (C) comprises:
(i) an ethylene homopolymer, and (ii) a density of 0.915
In the range of ~0.925g / cm ^3, (iii) a melt flow rate (MFR; ASTM D 1238,190 ℃, load 2.16k
g) is in the range of 0.5 to 6.0 g / 10 minutes. Also,
Another polyethylene resin composition for a film according to the present invention is a linear ethylene / α-olefin copolymer (D) obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. D1) 30 to 70% by weight, and 70 to 30% by weight of a linear ethylene / α-olefin copolymer (D2) obtained by copolymerizing ethylene and an α-olefin having 3 to 20 carbon atoms. Blend 90-9
5 parts by weight and (B) 5 to 10 parts by weight of a high-density polyethylene comprising ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms [Blend (D) and component (B) ) Is 100 parts by weight]. The linear ethylene / α-olefin copolymer (D1) has (i) an ethylene content of 50% by weight or more and 100% by weight or less. % By weight, and (i
i) the density is in the range of 0.905 to 0.935 g / cm ³ , and (iii) the melt flow rate (MFR; ASTM D 123)
(8,190 ° C., load 2.16 kg) is in the range of 0.1 to 5.0 g / 10 min, and (iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 1.5 to 2.5. (V) The normal-temperature n-decane extraction amount is 2.0% by weight or less, and the linear ethylene / α-olefin copolymer (D2) is (i)
The ethylene content is in the range of 50% by weight to less than 100% by weight, and (ii) the density is 0.915 to 0.945 g / cm ^3.
(Iii) Melt flow rate (MFR; AS
TM D 1238, 190 ° C, load 2.16kg) 2.0-80.0g
/ 10 minutes, (iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 2.5 to 5.0, and (v) the normal temperature n-decane extraction amount is 2.0 to 10 0.0% by weight, wherein the high density polyethylene (B) comprises (i)
(Ii) having an ethylene content in the range of 50 to 100% by weight;
Having a density in the range of 0.945 to 0.975 g / cm ³ , and (iii) a melt flow rate (MFR; ASTM D 123).
(8,190 ° C., load 2.16 kg) is in the range of 0.5 to 10.0 g / 10 minutes, and (iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 2.5 to 5.0. It is characterized by having.

In this composition, the high-pressure low-density polyethylene (C) is added in an amount of 5 to 5 parts by weight based on 100 parts by weight of the total amount of the blend (D) and the high-density polyethylene (B).
20 parts by weight can be contained.

These polyethylene resin compositions may contain an anti-blocking agent or a slip agent.

[0012]

DETAILED DESCRIPTION OF THE INVENTION The polyethylene resin composition for a film according to the present invention will be specifically described below.

The polyethylene resin composition for a film according to the present invention comprises a linear ethylene / α-olefin copolymer (A), a high-density polyethylene (B) and, if necessary, a high-pressure low-density polyethylene (C). Contains.

Another polyethylene resin composition for a film according to the present invention comprises a blend of a linear ethylene / α-olefin copolymer (D1) and a linear ethylene / α-olefin copolymer (D2). (D), high-density polyethylene (B), and if necessary, high-pressure low-density polyethylene (C).

First, these components will be described. Linear ethylene / α-olefin copolymer (A) In the linear ethylene / α-olefin copolymer (A) used in the present invention, the copolymer having 3 to 20 carbon atoms used for copolymerization with ethylene. As the α-olefin, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-
Dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicodecene and the like.
Of these, α-olefins having 4 to 10 carbon atoms, particularly α-olefins having 5 to 8 carbon atoms, are preferred.

In the present invention, the above-mentioned α-olefins can be used alone or in combination of two or more. The linear ethylene / α-olefin copolymer (A) used in the present invention has a constitutional unit derived from ethylene of 50% by weight or more and less than 100% by weight, preferably 5% by weight or less.
5 to 98% by weight, more preferably 65 to 95% by weight,
Particularly preferably, it is present in an amount of 75 to 90% by weight, and the constituent unit derived from an α-olefin having 3 to 20 carbon atoms is 50% by weight or less, preferably 2 to 45% by weight, more preferably 5 to 35% by weight. %, Particularly preferably from 10 to 25% by weight.

The composition of the linear ethylene / α-olefin copolymer (A) is usually about 200 in a 10 mmφ sample tube.
A ¹³ C-NMR spectrum of a sample in which 1 mg of the copolymer was uniformly dissolved in 1 ml of hexachlorobutadiene was measured at a measurement temperature of 120 ° C., 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 It is determined by measuring under measurement conditions of 6 μsec.

The linear ethylene α- used in the present invention
The olefin copolymer (A) has a density of 0.905 to 0.5.
935 g / cm ³ , preferably 0.910 to 0.930
g / cm ³ , more preferably 0.915 to 0.925
g / cm ³ . When a linear ethylene / α-olefin copolymer (A) having a density within the above range is used,
A polyethylene resin composition having a low content of low molecular weight components is obtained, and a film formed from the composition has good blocking resistance and less bleed out to the film surface over time. Further, a linear ethylene / α-olefin copolymer (A) having such a density
Does not adversely affect transparency or other physical properties.

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

The linear ethylene / α-olefin copolymer (A) has a melt flow rate (MFR; ASTM
D 1238, 190 ° C, load 2.16 kg) is 0.1 to 3.0 g /
It is in the range of 10 minutes, preferably 0.3 to 1.0 g / 10 minutes. The use of the linear ethylene / α-olefin copolymer (A) having a melt flow rate within the above range can provide a polyethylene resin composition having a high impact strength and capable of providing a film which is hardly reduced in strength even at high density. Is obtained.

The molecular weight distribution (Mw) of the linear ethylene / α-olefin copolymer (A) measured by GPC
/ Mn: Mw = weight average molecular weight, Mn = number average molecular weight)
Is desirably in the range of 1.5 to 2.5, preferably 1.6 to 2.2.

The molecular weight distribution (Mw / Mn) was measured as follows using GPC-150C manufactured by Millipore. The separation column is TSK GNH HT,
The column size is 72 mm in diameter and 600 mm in length,
The column temperature was 140 ° C., and the mobile phase used was O-dichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.025% by weight of BHT (manufactured by Takeda Pharmaceutical Company Limited) as an antioxidant. The sample was moved at 0 ml / min, the sample concentration was 0.1% by weight, the sample injection amount was 500 microliter, and a differential refractometer was used as a detector. Standard polystyrene is
For a molecular weight of Mw <1000 and Mw> 4 × 10 ⁶ , Tosoh Corp.
About ⁶ , the product made by Pressure Chemical Company was used.

The straight-chain ethylene α- used in the present invention
The room temperature n-decane extraction amount of the olefin copolymer rubber (A) is 2.0% by weight or less, preferably 0.1 to 1.5% by weight, more preferably 0.2 to 1.0% by weight. is there. When this linear ethylene / α-olefin copolymer (A) having a normal temperature n-decane extraction amount of 2.5% by weight or less is used, a polyethylene film having an excellent balance between blocking resistance and transparency can be obtained. Can be

The amount of n-decane extracted at room temperature is determined by dissolving 5 g of a sample in 200 cc of n-decane at 145 ° C. for 1 hour, allowing it to stand naturally, and dissolving in the solution at room temperature. It is determined by measuring the amount of the chain ethylene / α-olefin copolymer.

In the present invention, linear ethylene.α-
The olefin copolymer (A) is preferably 90 parts by weight based on 100 parts by weight of the total amount of the linear ethylene / α-olefin copolymer (A) and the high-density polyethylene (B).
It is used in a proportion of up to 95 parts by weight.

The linear ethylene / α-olefin copolymer (A) as described above is disclosed in, for example, JP-A-6-9724, JP-A-6-136195, and JP-A-6-136.
196, a so-called metallocene-based olefin polymerization catalyst containing a metallocene catalyst component described in JP-A-6-207057 and the like, in the presence of ethylene and an α-olefin having 3 to 20 carbon atoms, The copolymer can be produced by copolymerizing so that the density of the obtained copolymer is 0.925 to 0.935 g / cm ³ .

Such a metallocene catalyst usually has at least one ligand having a cyclopentadienyl skeleton.
Metallocene catalyst component (a) comprising a transition metal compound of Group IVB of the periodic table, an organoaluminum oxy compound catalyst component (b), a particulate carrier (c), and, if necessary, an organoaluminum compound catalyst component (d ), An ionized ionic compound formed from the catalyst component (e).

The metallocene catalyst component (a) preferably used in the present invention is a transition metal compound of Group IVB of the periodic table having at least one ligand having a cyclopentadienyl skeleton. Examples of such a transition metal compound include a transition metal compound represented by the following general formula [I].

ML ¹ _x ... [I] In the formula, x is the valence of the transition metal atom M. M is a transition metal atom selected from Group IVB of the periodic table represented by zirconium.

L ¹ is a ligand which coordinates to the transition metal atom M, and at least one of these ligands L ¹
Is a ligand having a cyclopentadienyl skeleton.
As the ligand L ¹ having a cyclopentadienyl skeleton coordinated to the transition metal atom M as described above, specifically,
Cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, tetramethylcyclopentadienyl group, pentamethylcyclopentadienyl group, methylethylcyclopentadienyl group And an alkyl-substituted cyclopentadienyl group such as hexylcyclopentadienyl group, or an indenyl group, a 4,5,6,7-tetrahydroindenyl group or a fluorenyl group.

When the compound represented by the above general formula [I] contains two or more groups having a cyclopentadienyl skeleton, two of the groups having a cyclopentadienyl skeleton are connected to each other by ethylene, propylene or the like. An alkylene group,
It may be bonded through a substituted alkylene group such as isopropylidene diphenylmethylene or the like, or a silylene group or a substituted silylene group such as a dimethylsilylene group, a diphenylsilylene group or a methylphenylsilylene group.

The ligand L ¹ other than the ligand having a cyclopentadienyl skeleton is a hydrocarbon group having 1 to 12 carbon atoms; an alkoxy group such as a methoxy group; an aryloxy group such as a phenoxy group; a trimethylsilyl group; A trialkylsilyl group such as a triphenylsilyl group; SO ₃ R (R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as a halogen), a halogen atom or a hydrogen atom.

As the organoaluminum oxy compound catalyst component (b), aluminoxane is preferably used. Specifically, methylaluminoxane, ethylaluminoxane, methylethylaluminoxane having a repeating unit represented by the formula -Al (R) O-, wherein R is an alkyl group, is usually about 3 to 50. And the like, and can be prepared by a conventionally known production method.

The particulate carrier (c) used in the preparation of the catalyst for olefin polymerization is an inorganic or organic compound, and is a granular or particulate solid having a particle size of usually about 10 to 300 μm.

As the inorganic carrier, a porous oxide is preferable, and specific examples thereof include SiO ₂ , Al ₂ O ₃ , MgO and the like or a mixture thereof. As the organoaluminum compound catalyst component (d) optionally used in the preparation of the catalyst for olefin polymerization, specifically, trialkylaluminum such as trimethylaluminum, alkenylaluminum such as isoprenylaluminum, dimethylaluminum chloride and the like Examples thereof include dialkylaluminum halides.

Examples of the ionized ionic compound catalyst component (e) include triphenylboron, MgCl ₂ , and Al described in US Pat. No. 5,321,106.
Lewis acids such as ₂ O ₃ and SiO ₂ —Al ₂ O ₃ ; ionic compounds such as triphenylcarbenium tetrakis (pentafluorophenyl) borate; carborane compounds such as dodecaborane and bis-n-butylammonium (1-carbedodeca) borate Is mentioned.

The linear ethylene α- used in the present invention
The olefin copolymer (A) can be prepared by mixing ethylene and C3 to C2 in various conditions in the gas phase, or in a slurry or solution phase in the presence of the olefin polymerization catalyst.
It can be obtained by copolymerizing an α-olefin with 0.

High-density polyethylene (B) The high-density polyethylene (B) used in the present invention is an ethylene homopolymer (B1) or ethylene and C3 to C2.
A copolymer (B2) with an α-olefin of 0.

Examples of the α-olefin having 3 to 20 carbon atoms used for copolymerization with ethylene include propylene, 1-butene, 1-pentene, 1-hexene and 4-methyl-1-pentene. , 1-octene, 1-decene, 1-dodecene,
Examples thereof include 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, and 1-eicodecene. Of these, α-olefins having 3 to 10 carbon atoms, particularly α-olefins having 4 to 8 carbon atoms, are preferred.

In the present invention, the above-mentioned α-olefins can be used alone or in combination of two or more. The ethylene / α-olefin copolymer (B2) used in the present invention has 5 structural units derived from ethylene.
0 to less than 100% by weight, preferably 80 to 98%
% By weight, more preferably from 85 to 96% by weight, particularly preferably from 90 to 94% by weight, having from 3 to 3 carbon atoms.
It is desirable that the constituent unit derived from 20 α-olefins is present in an amount of 50% by weight or less, preferably 20 to 2% by weight, more preferably 15 to 4% by weight, particularly preferably 10 to 6% by weight.

High density polyethylene used in the present invention
(B) has a density (ASTM D 1505) of 0.945 to 0.9.
75g / cm^Three , Preferably 0.947 to 0.970 g
/ Cm ^Three , More preferably 0.950 to 0.965 g
/ Cm^Three In the range. High-density PO with a density in the above range
When ethylene (B) is used, a film having excellent transparency and rigidity can be obtained.
Polyethylene resin composition capable of providing film
Is obtained.

The high-density polyethylene (B) had a melt flow rate (MFR; ASTM D1238, 190 ° C., load
2.16 kg) is 0.5 to 10.0 g / 10 min, preferably 0.6 to 8 g / 10 min, and more preferably 0.8 to 5 g.
/ 10 minutes. When a high-density polyethylene (B) having a melt flow rate within the above range is used, a polyethylene resin composition capable of providing a film having an excellent balance between fluidity and strength can be obtained.

The molecular weight distribution (Mw / Mn: Mw = weight average molecular weight, Mn = number average molecular weight) of the high-density polyethylene (B) measured by GPC is 2.5 to 5.0,
Preferably, it is in the range of 2.8 to 4.0.

High density polyethylene (B) as described above
Can be produced by a conventionally known method, that is, a so-called medium / low pressure method. In the present invention, the high-density polyethylene (B) is the total amount of the linear ethylene / α-olefin copolymer (A) and the high-density polyethylene (B), or the linear ethylene / α-olefin copolymer. The amount of the blend (D) of (D1) and (D2) and the high-density polyethylene (B) is preferably 5 to 100 parts by weight in total.
It is used in a proportion of 10 to 10 parts by weight.

High pressure method low density polyethylene (C) High pressure method low density polyethylene (C) used in the present invention
Has a density in the range of 0.915 to 0.925 g / cm ³ , preferably 0.916 to 0.924 g / cm ³ , more preferably 0.918 to 0.922 g / cm ³ .
High pressure method low density polyethylene (C) whose density is in the above range
By using the above, a polyethylene resin composition capable of improving the transparency of the film is obtained.

The high flow method low density polyethylene (C) has a melt flow rate (MFR; ASTM D 1238,1).
90 ° C., load 2.16 kg) is in the range of 0.5 to 6.0 g / 10 min, preferably 0.6 to 3.0 g / 10 min. When a high-pressure low-density polyethylene (C) having a melt flow rate within the above range is used, a polyethylene resin composition capable of performing stable film formation can be obtained.

In the present invention, the high-pressure-process low-density polyethylene (C) is the total amount of the linear ethylene / α-olefin copolymer (A) and the high-density polyethylene (B) or the linear ethylene / α-olefin. -Olefin copolymer (D1)
5 to 20 parts by weight, preferably 6 to 15 parts by weight, and more preferably 7 parts by weight, based on 100 parts by weight of the total amount of the blend (D) and high-density polyethylene (B) of
It is used in a proportion of 10 to 10 parts by weight.

Blend (D) The blend (D) used in the present invention comprises a linear ethylene / α-olefin copolymer (D1) and a linear ethylene / α-olefin copolymer (D2) Consists of

In the present invention, the blend (D) comprises:
It is preferably used in a proportion of 90 to 95 parts by weight based on 100 parts by weight of the total amount of the blend (D) and the high-density polyethylene (B).

<Linear ethylene / α-olefin copolymer (D1)> The linear ethylene / α-olefin copolymer used in the present invention is used.
In the olefin copolymer (D1), as the α-olefin having 3 to 20 carbon atoms used for copolymerization with ethylene, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 4 -Methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicodecene And the like. Among them, those having 4 to 10 carbon atoms
Α-olefins, especially α-olefins having 5 to 8 carbon atoms, are preferred.

These α-olefins can be used alone or in combination of two or more. The linear ethylene / α-olefin copolymer (D) used in the present invention
1) is that the structural unit derived from ethylene is 50% by weight or more and less than 100% by weight, preferably 55-98% by weight, more preferably 65-95% by weight, and particularly preferably 75% by weight.
Present in an amount of up to 90% by weight, and α-
It is desirable that the constituent unit derived from the olefin is present in an amount of 50% by weight or less, preferably 45 to 2% by weight, more preferably 35 to 5% by weight, and particularly preferably 25 to 10% by weight.

The straight-chain ethylene α- used in the present invention
The olefin copolymer (D1) has a density of 0.905 to 0.905.
0.935 g / cm ³ , preferably 0.910 to 0.9
30 g / cm ³ , more preferably 0.915 to 0.9
It is in the range of 25 g / cm ³ . When the linear ethylene / α-olefin copolymer (D1) having a density in the above range is used, a polyethylene resin composition having a low content of low molecular weight components is obtained, and a film formed from the composition is Good blocking resistance and less bleed-out over time on the film surface. Further, the linear ethylene / α-olefin copolymer (D1) having such a density does not adversely affect transparency and other physical properties.

The linear ethylene / α-olefin copolymer (D1) has a melt flow rate (MFR; AS
TM D 1238, 190 ° C, load 2.16 kg) is 0.1 to 5.0 g
/ 10 minutes, preferably 0.1 to 3.0 g / 10 minutes, more preferably 0.3 to 1.0 g / 10 minutes.
If the melt flow rate is within the above range,
When the α-olefin copolymer (D1) is used, a polyethylene resin composition capable of providing a film having high impact strength and hardly causing a decrease in strength even at high density can be obtained.

The molecular weight distribution of the linear ethylene / α-olefin copolymer (D1) measured by GPC (M
(w / Mn: Mw = weight average molecular weight, Mn = number average molecular weight) is desirably in the range of 1.5 to 2.5, preferably 1.6 to 2.2.

The linear ethylene α- used in the present invention
Room temperature n-decane extraction amount of the olefin copolymer (D1) is 2.0% by weight or less, preferably 0.1 to 1.5% by weight,
More preferably, it is in the range of 0.2 to 1.0% by weight.
By using the linear ethylene / α-olefin copolymer (D1) having a normal temperature n-decane extraction amount of 2.0% by weight or less, a polyethylene film having an excellent balance between blocking resistance and transparency can be obtained. Can be

The above-mentioned linear ethylene / α-olefin copolymer (D1) is a copolymer of linear ethylene / α-olefin copolymer (D1) and linear ethylene / α-olefin copolymer (D2). 30 to 100% by weight in total
It is used in a proportion of 70% by weight, preferably 40 to 65% by weight, more preferably 50 to 60% by weight.

The linear ethylene / α-olefin copolymer (D1) as described above is disclosed in, for example, JP-A-6-9724, JP-A-6-136195, and JP-A-6-13.
In the presence of a so-called metallocene-based olefin polymerization catalyst containing a metallocene catalyst component described in JP-A-6196, JP-A-6-207057, etc., ethylene and an α-olefin having 3 to 20 carbon atoms are converted into The copolymer can be produced by copolymerizing so that the density of the obtained copolymer is 0.905 to 0.935 g / cm ³ . The metallocene olefin polymerization catalyst is as described above.

<Linear ethylene / α-olefin copolymer (D2)>
In the olefin copolymer (D2), as the α-olefin having 3 to 20 carbon atoms used for copolymerization with ethylene, specifically, propylene, 1-butene, 1-pentene, 1-hexene, 4 -Methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicodecene And the like. Among them, those having 3 to 10 carbon atoms
Α-olefins, especially α-olefins having 4 to 8 carbon atoms, are preferred.

In the present invention, the above-mentioned α-olefins can be used alone or in combination of two or more. The linear ethylene / α-olefin copolymer (D2) used in the present invention has a constitutional unit derived from ethylene of 50 to less than 100% by weight, preferably 60 to 98% by weight, more preferably 70 to 98% by weight. It is present in an amount of 96% by weight, particularly preferably 85 to 94% by weight, the constituent units derived from α-olefins having 3 to 20 carbon atoms being 50% by weight or less, preferably 40 to 2% by weight, more preferably 30-4% by weight, particularly preferably 15-6%
Desirably, it is present in an amount of weight percent.

The linear ethylene α- used in the present invention
The olefin copolymer (D2) has a density of 0.915 to
0.945 g / cm ³ , preferably 0.920 to 0.9
43 g / cm ³ , more preferably 0.925 to 0.9
It is in the range of 40 g / cm ³ . When the linear ethylene / α-olefin copolymer (D2) having a density in the above range is used, a polyethylene resin composition capable of providing a film having an excellent balance between transparency and rigidity can be obtained.

The linear ethylene / α-olefin copolymer (D2) has a melt flow rate (MFR; AS
TM D 1238, 190 ° C, load 2.16 kg) is 2.0 to 80.0
g / 10 minutes, preferably 5 to 60 g / 10 minutes. When a linear ethylene / α-olefin copolymer (D2) having a melt flow rate in the above range is used, a polyethylene resin composition having excellent fluidity and easy to form a film can be obtained.

The molecular weight distribution of the linear ethylene / α-olefin copolymer (D2) measured by GPC (M
(w / Mn: Mw = weight average molecular weight, Mn = number average molecular weight) is desirably in the range of 2.5 to 5.0, preferably 2.8 to 3.5.

The straight-chain ethylene α- used in the present invention
The room temperature n-decane extraction amount of the olefin copolymer (D2) is 2.0 to 10.0% by weight, preferably 2.2 to 5.0% by weight, more preferably 2.4 to 4.0% by weight. Range. By using the linear ethylene / α-olefin copolymer (D2) whose n-decane extraction amount at normal temperature is within the above range, a polyethylene film having an excellent balance between blocking resistance and transparency can be obtained.

The above-mentioned linear ethylene / α-olefin copolymer (D2) is a mixture of the linear ethylene / α-olefin copolymer (D1) and the linear ethylene / α-olefin copolymer (D2). 70 to 100% by weight in total
It is used in a proportion of 30% by weight, preferably 60 to 35% by weight, more preferably 50 to 40% by weight.

The linear ethylene (D2) having the above properties can be prepared using a conventionally known titanium-based olefin polymerization catalyst. Polyethylene resin composition The polyethylene resin composition for a film according to the present invention,
If necessary, conventionally known additives such as an anti-blocking agent, a slip agent, a light stabilizer, an ultraviolet absorber, an antistatic agent, and a heat-resistant stabilizer may be blended within a range that does not impair the object of the present invention. it can. Specific examples of the antiblocking agent include natural silica, synthetic silica, zeolite, amorphous zeolite, diatomaceous earth, erucamide, stearamide, palmitamide, oleamide and the like. Among them, zeolite, erucamide and the like are preferably used.

Such an antiblocking agent is usually used in an amount of 100 to 10 parts by weight based on 100 parts by weight of the total amount of the resin component.
000 ppm, preferably 1000-8000 ppm,
More preferably, it is used at a ratio of 3000 to 7000 ppm.

Examples of the slip agent include metal soaps, hydrocarbons such as natural waxes (such as carba wax), petroleum waxes (such as paraffin wax), higher fatty acids and their derivatives (stearic acid and its esters and ethers), and the like. Is mentioned.

Such a slip agent is usually used in an amount of 100 to 2000 pp based on 100 parts by weight of the total amount of the resin component.
m, preferably from 500 to 1500 ppm, more preferably from 700 to 1300 ppm.

The polyethylene resin composition for a film according to the present invention comprises a resin component containing the above additives such as an anti-blocking agent, a slip agent and, if necessary, a light stabilizer, an ultraviolet absorber and an antistatic agent. It is obtained by mixing at about 200 ° C. with an extruder after mixing using a mixing device such as the above.

Film Forming Method The polyethylene resin composition for a film according to the present invention is extruded from a die while being melt-kneaded from an extruder to form a film. In this case, the die may be a circular die or a circular die. The extruded film may be cooled with air or water. In particular, when a so-called water-cooled inflation molding method is used, in which a circular die is used to form an inflation film and the film is cooled with water from the outside, the film is transparent, has high strength, has excellent blocking resistance, and has good opening properties. A film is obtained.

[0071]

Industrial Applicability The polyethylene resin composition for a film according to the present invention is excellent in moldability, exhibits high mechanical strength, and can produce a film excellent in balance between transparency and anti-blocking property and excellent in opening property. . In particular, the water-cooled blown film obtained from this composition has an excellent balance of physical properties such as openability, transparency, and blocking resistance, and is suitable for packaging applications.

[0072]

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

The evaluation of the films in Examples and Comparative Examples was performed as follows. (1) Opening property The opening property of the film immediately after molding was evaluated by sensory evaluation. A film that opened naturally without blocking was evaluated as “good openability”, and a film that blocked the film and did not open naturally was evaluated as “poor openness”.

(2) Haze (Haze) The haze, which is an index of the transparency of the film, is determined by ASTM D
It was measured according to 1003. (3) Blocking resistance (blocking force) The blocking force was measured according to ASTM D1893.

The polyethylene used in Examples and Comparative Examples is as follows. Linear ethylene / α-olefin copolymer (1) Linear ethylene / 1-hexene copolymer (D1-
1) ・ Catalyst used in the production: Catalyst for metallocene olefin polymerization ・ Ethylene content: 89% by weight ・ Density: 0.915 g / cm ³・ MFR (ASTM D 1238, 190 ° C, load 2.16 kg): 0. 5
g / 10 min ・ Mw / Mn: 2.0 ・ Normal temperature n-decane extraction amount: 0.8% by weight (2) Linear ethylene / 4-methyl-1-pentene copolymer (D2-1) ・ Production Catalyst used at the time of: Titanium-based olefin polymerization catalyst ・ Ethylene content: 97% by weight ・ Density: 0.945 g / cm ³・ MFR (ASTM D 1238, 190 ° C, load 2.16 kg): 60 g
/ 10 min Mw / Mn: 2.7 Room temperature n-decane extraction: 0.5% by weight High density polyethylene (1) ethylene / 1-butene copolymer (B-1) Ethylene content: 99% by weight density (ASTM D 1505): 0.954g / cm 3 · MFR (ASTM D 1238,190 ℃, load 2.16 kg): 1.0
g / 10 minutes Mw / Mn: 3.1

[0076]

Example 1 60 parts by weight of the above linear ethylene / 1-hexene copolymer (D1-1) prepared using a metallocene olefin polymerization catalyst and a titanium olefin polymerization catalyst were prepared. The above linear ethylene 4-methyl
After blending 40 parts by weight of -1-pentene copolymer (D2-1) with a Henschel mixer, the mixture was extruded at about 200 ° C. with an extruder to obtain a blend.

Next, 95 parts by weight of the above blend, 5 parts by weight of high-density polyethylene (B-1), and a master batch of an antiblocking agent (synthetic zeolite) and a slip agent (erucamide) were blended. Each of the anti-blocking agent and the slip agent has a final concentration of 5000 pp.
m and 1200 ppm to obtain a polyethylene resin composition.

Next, a film having a thickness of 50 μm was formed from the obtained polyethylene resin composition by a water-cooled inflation molding method under the following conditions. [Water-cooled inflation molding conditions] Molding machine: Water-cooled inflation molding machine manufactured by Yamaguchi Seisakusho Co., Ltd. Die diameter: 55 mmφ Lip width: 2.0 mm Molding temperature: 210 ° C Folding width: 130 mm Cooling water temperature: 20 ° C As described above About the obtained film, opening property,
Haze and blocking resistance tests were performed according to the above-described methods.

The results are shown in Table 1.

[0080]

Example 2 In Example 1, the blending amounts of the above blend and the high-density polyethylene (B-1) were 90
The same procedure as in Example 1 was carried out except that the weight parts were 10 parts by weight.

The results are shown in Table 1.

[0082]

Comparative Example 1 In Example 1, the blending amounts of the above blend, high-density polyethylene (B-1), antiblocking agent and slipping agent were respectively 100 parts by weight, 0 parts by weight, 5 parts by weight and 5 parts by weight. Except having performed, it carried out similarly to Example 1.

[0083]

Comparative Example 2 In Comparative Example 1, except that the molding temperature in the water-cooled inflation molding method was changed to 220 ° C.
Performed in the same manner as in Comparative Example 1.

The results are shown in Table 1.

[0085]

[Table 1]

Claims (6)

[Claims] (1) (A) ethylene and α having 3 to 20 carbon atoms
-Linear ethylene obtained by copolymerizing olefin
90 to 95 parts by weight of an α-olefin copolymer; and (B) 5 to 10 parts by weight of a high-density polyethylene composed of (B) an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. (A) and (B)
Is 100 parts by weight]. The linear ethylene / α-olefin copolymer (A) comprises:
(i) the ethylene content is in the range of 50% by weight or more and less than 100% by weight, and (ii) the density is 0.905 to 0.935 g / c.
in the range of m ^3, (iii) a melt flow rate (MF
R; ASTM D 1238, 190 ° C, load 2.16 kg) is 0.1-3.
0 g / 10 min, (iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 1.5 to 2.5, and (v) the normal temperature n-decane extraction amount is 2.0 wt. % Or less, and the high-density polyethylene (B) has (i) an ethylene content of 5%.
(Ii) a density of 0.945.
In the range of ~0.975g / cm ^3, (iii) a melt flow rate (MFR; ASTM D 1238,190 ℃, load 2.16k
g) is in the range of 0.5 to 10.0 g / 10 minutes, and (iv)
A polyethylene resin composition for a film, wherein the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 2.5 to 5.0. 2. The total amount of said linear ethylene / α-olefin copolymer (A) and high-density polyethylene (B) is 1
A composition comprising 5 to 20 parts by weight of a high-pressure method low-density polyethylene (C) based on 00 parts by weight, wherein the high-pressure method low-density polyethylene (C) is (i) an ethylene homopolymer. Yes, (ii) Density 0.915 to 0.925 g
/ Cm ³ and (iii) the melt flow rate (M
FR; ASTM D 1238, 190 ℃, load 2.16kg) 0.5 ~
The polyethylene resin composition for a film according to claim 1, wherein the content is in a range of 6.0 g / 10 minutes. 3. The polyethylene resin composition for a film according to claim 1, which is used for forming a water-cooled blown film. (D) ethylene and α having 3 to 20 carbon atoms.
-Linear ethylene obtained by copolymerizing olefin
α-olefin copolymer (D1) 30 to 70% by weight, and a linear ethylene / α-olefin copolymer (D2) obtained by copolymerizing ethylene with an α-olefin having 3 to 20 carbon atoms. 90) to 95 parts by weight of a blend consisting of 70 to 30% by weight and (B) a high-density polyethylene 5 to 10 consisting of an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. Parts by weight [total amount of blend (D) and component (B) is 100
Parts by weight], and the linear ethylene / α-olefin copolymer (D1)
Has a (i) ethylene content in the range of 50% by weight or more and less than 100% by weight, and (ii) a density of 0.905 to 0.935 g.
/ Cm ³ and (iii) the melt flow rate (M
FR; ASTM D 1238, 190 ℃, load 2.16kg) is 0.1 ~
(Iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 1.5 to 2.5, and (v) the normal temperature n-decane extraction amount is 2. 0% by weight or less, and the linear ethylene / α-olefin copolymer (D2)
Has a (i) ethylene content in a range of 50% by weight or more and less than 100% by weight, and (ii) a density of 0.915 to 0.945 g.
/ Cm ³ and (iii) the melt flow rate (M
FR; ASTM D 1238, 190 ° C, load 2.16 kg) 2.0-8
(Iv) the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 2.5 to 5.0, and (v) the normal temperature n-decane extraction is 2. 0-10.
The high-density polyethylene (B) has (i) an ethylene content of 5% by weight.
(Ii) a density of 0.945.
In the range of ~0.975g / cm ^3, (iii) a melt flow rate (MFR; ASTM D 1238,190 ℃, load 2.16k
g) is in the range of 0.5 to 10.0 g / 10 minutes, and (iv)
A polyethylene resin composition for a film, wherein the molecular weight distribution (Mw / Mn) measured by GPC is in the range of 2.5 to 5.0. 5. The amount of 5 to 20 parts by weight based on 100 parts by weight of the total amount of the blend (D) and the high-density polyethylene (B).
A composition comprising parts by weight of a high-pressure low-density polyethylene (C), wherein the high-pressure low-density polyethylene (C) is (i) an ethylene homopolymer, and (ii) has a density of 0.915. ~ 0.925g
/ Cm ³ , and (iv) melt flow rate (MF
R: ASTM D 1238, 190 ° C, load 2.16 kg) 0.5 to 6.
The polyethylene resin composition for a film according to claim 4, wherein the content is within a range of 0 g / 10 minutes. 6. The polyethylene resin composition for a film according to claim 4, which is used for forming a water-cooled blown film.