JPH11152376A - Polyethylene composition for biaxially oriented film and biaxially oriented film prepared therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a biaxially oriented film excellent in stretchability, moldability, and productivity and exhibits a small hot slip by compounding an ethylene-α-olefin copolymer having specified physical properties with polyethylene. SOLUTION: 20-99 wt.%, pref. 30-90 wt.% of an ethylene-α-olefin copolymer which is produced in the presence of a single-site catalyst and has a density of 0.880-0.950 g/cm<3> , an MFR2.16 (190 deg.C, 2.16 kg load) of 0.1-2.0 g/10 min, a ratio of MFR10.0 (190 deg.C, 10 kg load)/MFR2.16 of 3.0-8.0, a mol.wt. distribution (Mw/Mn) of 2.0-4.0, a standard deviation of amt. of eluate vs elution temp. obtd. by temp. rise elution fractionation(TREF) satisfying σ<=17, and at least two peaks in the differential elution curve obtd. by TREF is compounded with 80-1 wt.%, pref. 70-10 wt.%, polyethylene which has a density of 0.900-0.960 g/cm<3> and an MFR2.16 (190 deg.C, 2.16 kg load) of 5 g/10 min or higher to give the polyethylene compsn. for biaxially oriented films having a flowability index of 45-100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a polyethylene composition containing an ethylene-α-olefin copolymer as a main component produced from a single-site catalyst capable of producing a biaxially stretched film, and a biaxial composition comprising this composition. It relates to a stretched film.

[0002]

2. Description of the Related Art A polyethylene composition and a production method capable of producing a biaxially stretched film are disclosed in JP-A-4-35701.
No. 7 discloses that a raw resin mainly composed of linear low-density polyethylene is cooled and solidified while being melt-extruded into a substantially unoriented sheet, and then subjected to a specific biaxial stretching method at a specific temperature and stretching. A method for producing a polyethylene-based biaxially stretched film at a magnification is disclosed.

Further, Japanese Patent Application Laid-Open No. Hei 5-4276 discloses that
A raw resin mainly composed of linear low-density polyethylene is cooled and solidified while being extruded into a substantially unoriented sheet while being extruded at a specific temperature and a draw ratio by a simultaneous biaxial stretching method. A method for producing a stretched film is disclosed.

Further, Japanese Patent Application Laid-Open No. 7-309962 discloses a heat-shrinkable, fracture-resistant biaxially stretched thermoplastic film suitable for use in the production of food packaging bags, which has a specific density and melt index. A biaxially stretched thermoplastic film containing an ethylene-α-olefin copolymer having a molecular weight distribution, a melting point, and a Young's modulus and shrinking by about 45% at 90 ° C. is disclosed.

[0005]

DISCLOSURE OF THE INVENTION The present invention relates to an ethylene-α-olefin copolymer produced from a single-site catalyst and polyethylene, which is excellent in stretchability, moldability and productivity, and has a small hot slip. An object of the present invention is to provide a polyethylene composition for a biaxially stretched film, which is suitable for producing a biaxially stretched film, and a biaxially stretched film comprising the composition.

[0006]

According to the present invention, there is provided an ethylene-α-olefin copolymer prepared from a single-site catalyst having the following characteristic (A) in an amount of 20 to 99% by weight and a polyethylene 80 having the following characteristic (B). To 1% by weight of a polyethylene composition for a biaxially stretched film having the following property (C). (A) Ethylene-α-olefin copolymer: (A-1) Density (d) = 0.880 to 0.950 (g /
^{cm 3) (A-2)} 190 ℃, melt flow rate at 2.16Kg load _{(MFR 2. 16) = 0.1~2.0 (} g / 1
0 min) (A-3) 190 ℃ , melt flow rate in 10.0Kg load (MFR _{10 .0)} and 190 ° C., 2.16 Kg
Ratio to the melt flow rate (MFR _2.16 ) under load (MFR _10.0 ) / (MFR _2.16 ) = 3.0 to 8.0 (A-4) Molecular weight distribution (Mw / Mn) = 2.0 to 4.0 ( A-5) Standard deviation of elution amount with respect to elution temperature obtained by temperature rise elution fractionation (TREF) σ ≦ 17 (A-6) Differential elution curve obtained by temperature rise elution fractionation (TREF) has two or more peaks (B) polyethylene: (B-1) density (d) = 0.900 to 0.960 (g /
^{cm 3) (B-2)} 190 ℃, melt flow rate at 2.16Kg load (MFR _{2. 16)} = 5 or more (g / 10 min) (C) biaxially oriented film for polyethylene composition: (C-1 ) Flow index = 45-1000

[0007] More preferably, the present invention relates to the above polyethylene composition for a biaxially stretched film, wherein the biaxially stretched film has a hot slip coefficient of 1.4 or less.

Further, the present invention relates to a biaxially stretched film comprising the above polyethylene composition for a biaxially stretched film.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polyethylene composition for a biaxially stretched film of the present invention comprises 20 to 99% by weight of an ethylene-α-olefin copolymer produced from a single-site catalyst having the following property (A). 80-1% by weight of polyethylene having (B), preferably ethylene-α- produced from a single-site catalyst having the following properties (A)
30 to 95% by weight of olefin copolymer and the following properties (B)
70 to 5% by weight of polyethylene having the following properties (A), more preferably 30 to 90% by weight of an ethylene-α-olefin copolymer produced from a single-site catalyst having the following properties (A), and polyethylene 70 to 10
% By weight, particularly preferably 50 to 80% by weight of an ethylene-α-olefin copolymer produced from a single-site catalyst having the following property (A) and 50 to 20% by weight of a polyethylene having the following property (B). The following characteristics (C)
It is a polyethylene composition for biaxially stretched films having the following.

(A) Ethylene-α-olefin copolymer: (A-1) Density (d) = 0.880 to 0.950 (g /
cm ^3), preferably 0.890 to .940 (g / c
m ³ ), more preferably 0.900 to 0.930 (g)
/ Cm ³ ), particularly preferably 0.905 to 0.925.
^{(G / cm 3) (A} -2) 190 ℃, melt flow rate at 2.16Kg load _{(MFR 2. 16) = 0.1~2.0 (} g / 1
0 min), preferably 0.2 to 2.0 (g / 10 min), more preferably 0.3 to 1.5 (g / 10 min), particularly preferably 0.4 to 1.2 (g / 10 min). 10 min) (a-3) 190 ℃ , melt flow rate in 10.0Kg load (MFR _{10 .0)} and 190 ° C., 2.16 Kg
Ratio with melt flow rate (MFR _2.16 ) under load (MFR _10.0 ) / (MFR _2.16 ) = 3.0-8.0,
Preferably 4.0 to 8.0, more preferably 4.5 to 8.0.
7.0, particularly preferably 5.0-6.5 (A-4) molecular weight distribution (Mw / Mn) = 2.0-4.0,
Preferably from 2.0 to 3.5, more preferably from 2.2 to
3.3, particularly preferably 2.5 to 3.2 (A-5) Standard deviation of the elution amount with respect to the elution temperature obtained by elevated temperature elution fractionation (TREF) σ ≦ 17, preferably σ ≦ 16, more preferably 9 <σ ≦ 15 (A-6) The differential elution curve obtained by temperature rise elution fractionation (TREF) has two or more peaks, preferably three or more peaks

(B) polyethylene: (B-1) density (d) = 0.900 to 0.960 (g /
cm ³ ), preferably 0.905 to 0.960 (g / c
m ³ ), more preferably 0.905 to 0.950 (g)
/ Cm ³ ), particularly preferably 0.910 to 0.950
^{(G / cm 3) (B} -2) 190 ℃, melt flow rate at 2.16Kg load (MFR _{2. 16)} = 5 or more (g / 10 min),
It is preferably 10 to 100 (g / 10 minutes), more preferably 20 to 100 (g / 10 minutes), and particularly preferably 25 (g / 10 minutes).
~ 100 (g / 10min)

(C) Polyethylene composition for biaxially stretched film: (C-1) Flow index = 45 to 1000, preferably 50
To 700, more preferably 50 to 500, particularly preferably 50 to 350.

When (A-2) MFR _2.16 is smaller than the above range, the fluidity is poor and biaxial stretching molding becomes difficult. On the other hand, if it is larger than the above range, the drawdown becomes large, and it becomes difficult to form the biaxially stretched film.

(A-3) If the flow rate is smaller than the above range, the fluidity is poor and biaxial stretching molding becomes difficult. On the other hand, if it is larger than the above range, the drawdown becomes large, and it becomes difficult to form the biaxially stretched film.

(A-4) When the molecular weight distribution (Mw / Mn) is larger than the above range, the stretchability is reduced, the thickness of the molded product is varied widely, and the surface smoothness is reduced.

Further, the polyethylene composition (C) for a biaxially stretched film preferably has the following characteristics. (C-2) Density (d) = 0.890-0.950 (g /
cm ^3), preferably from 0.895 to 0.950 (g / c
m ³ ), more preferably 0.900 to 0.940 (g)
/ Cm ³ ), particularly preferably 0.905 to 0.930
^{(G / cm 3) (C} -3) 190 ℃, melt flow rate at 2.16Kg load _{(MFR 2. 16) = 0.2~10.0 (} g /
10 minutes), preferably 0.5 to 5.0 (g / 10 minutes),
More preferably 0.5 to 3.3 (g / 10 min), particularly preferably 0.7 to 3.0 (g / 10 min) (C-4) melt flow rate at 190 ° C. and 10.0 kg load ( MFR _{10 .0)} and 190 ℃, 2.16Kg
Ratio to Melt Flow Rate (MFR _2.16 ) under Load (MFR _10.0 ) / (MFR _2.16 ) = 3.0 to 30, preferably 3.5 to 30, more preferably 5.0 to 2
5, particularly preferably 7.0-15.0 (C-5) molecular weight distribution (Mw / Mn) = 2.0-10.
0, preferably 3.0 to 10.0, more preferably 3.5 to 7.0, and particularly preferably 4.0 to 6.0 (C-6) elution temperature obtained by temperature-rise elution fractionation (TREF). Σ ≦ 25, preferably σ ≦ 20, and more preferably 9 <σ ≦ 20. (C-7) The differential elution curve obtained by temperature rise elution fractionation (TREF) has two or more peaks. , Preferably having three or more peaks

The number of peaks of the differential elution curve obtained by the above-mentioned TREF refers to a calculation obtained by differentiating twice the integrated elution curve at a temperature range of 0 to 135 ° C. and at a temperature of 1 ° C., preferably at a temperature of 2 ° C. The value is plotted on the vertical axis and the elution temperature is plotted on the horizontal axis. The calculated value obtained by differentiating twice is the number of convex inflection points. Then, the sum of all the differential values obtained by one differentiation is standardized as 100, and the differential value (T1, except 0 ° C. and 134 ° C.)
(T1−2) between the differential value and the differential value (T2) that is 2 ° C. lower than the differential value.
T2) is a number of differential values in which the difference (T3−T1) from the differential value (T3) higher than 0 and 2 ° C. higher than the differential value (T1) is −0.15 or less, particularly preferably the integral The sum of all the differential values obtained by differentiating the elution curve once at a temperature of 2 ° C. is defined as 100, and the differential value (T1, excluding 0 ° C. and 134 ° C.) and 2 ℃ lower differential value (T
2) is greater than or equal to 0.01, and the difference (T3−) from the differential value (T3) that is higher than the differential value (T1) by 2 ° C.
T1) is the number of differential values where -0.20 or less.

The ethylene-α-olefin copolymer (A) of the present invention is produced by copolymerizing ethylene with an α-olefin having 3 to 10 carbon atoms in the presence of a single-site catalyst.

The α-olefin having 3 to 10 carbon atoms includes propylene, butene-1, pentene-1, hexene-
1,4-methylpentene-1, octene-1 and the like.

The repeating unit derived from α-olefin in the copolymer of ethylene and α-olefin is as follows:
Usually, it is preferably in the range of 10 mol% or less, more preferably in the range of 0.1 to 5 mol%, and particularly preferably in the range of 0.1 to 5 mol%.
-4% by mole. α-olefin is
The ethylene-α-olefin copolymer may be used alone or in combination of two or more.

As the single-site catalyst, a combination of a metallocene compound of a transition metal of Group IV or V of the periodic table with an organoaluminum compound and / or an ionic compound is used.

As the transition metal of Group IV or V of the periodic table, titanium (Ti), zirconium (Zr), hafnium (Hf), vanadium (V) and the like are preferable.

The metallocene compound is a compound which is cross-linked by at least one cyclopentadienyl group, substituted cyclopentadienyl group, hydrocarbyl silicon or the like, and which is obtained by cross-linking a cyclopentadienyl group to oxygen, nitrogen and phosphorus atoms. Any known metallocene compound having a compound as a ligand can be used.

Specific examples of these metallocene compounds include dimethylsilyl (2,4-dimethylcyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (2,4-dimethyl Silicon-bridged metallocene compounds such as cyclopentadienyl) (3 ', 5'-dimethylcyclopentadienyl) hafnium dichloride, ethylenebisindenylzirconium dichloride, ethylenebisindenylhafnium dichloride, ethylenebis (methylindenyl)
Examples include indenyl-based cross-linked metallocene compounds such as zirconium dichloride and ethylenebis (methylindenyl) hafnium dichloride.

The organoaluminum compound used in combination with the above metallocene compound is represented by the general formula (-A
a linear or cyclic polymer represented by l (R) O-) n (R is a hydrocarbon group having 1 to 10 carbon atoms, including those partially substituted by a halogen atom and / or an RO group .N
Is the degree of polymerization and is 5 or more, preferably 10 or more)
And specific examples include methylalumoxane, ethylalumoxane, isobutylethylalumoxane, wherein R is a methyl, ethyl, or isobutyl group, respectively.

Further, other organic aluminum compounds include trialkylaluminum, dialkylhalogenoaluminum, sesquialkylhalogenoaluminum, alkenylaluminum, dialkylhydroaluminum, sesquialkylhydroaluminum and the like.

The ionic compound is represented by the general formula: C ⁺ .A
^- , C ⁺ is an oxidizing cation of an organic compound, an organometallic compound, or an inorganic compound, or a Bronsted acid comprising a Lewis base and a proton, and reacts with an anion of a metallocene ligand to form a metallocene cation. Can be generated. Specific examples thereof are disclosed in
JP-A-5-253711, JP-A-4-305585, JP-A-5-507756 and JP-A-5-502906 can be used.

In particular, an ionic compound of a tetrakis (pentafluorophenyl) borate anion and a triphenylcarbonium cation or a dialkylanilinium cation is preferred. These ionic compounds can be used in combination with the aforementioned organic aluminum compounds.

As the method of copolymerizing ethylene and α-olefin with the above single-site catalyst, various well-known methods can be employed, such as fluidized-bed gas-phase polymerization in an inert gas or stirring gas-phase polymerization. Polymerization, slurry polymerization in an inert solvent, bulk polymerization using a monomer as a solvent, and the like.

The polyethylene (B) of the present invention is a high-pressure low-density polyethylene, a high-density polyethylene, or an ethylene-α-olefin copolymer containing the (A) ethylene-α-olefin copolymer produced by the single-site catalyst. Polyethylene polymers such as coalescing are preferred.

Examples of the polyethylene polymer include a homopolymer and an ethylene-α-olefin copolymer of ethylene and a small amount of α-olefin. For example, the Phillips method obtained by polymerization using a catalyst such as chromium oxide supported on ethylene and alumina or silica-alumina, the standard method obtained by polymerization using a catalyst such as molybdenum oxide supported on alumina, Examples thereof include polyethylene and an ethylene-α-olefin copolymer obtained by polymerization using a Ziegler catalyst comprising a transition metal compound and an organometallic compound.

As the high-pressure low-density polyethylene, those produced by high-pressure radical polymerization can be used.

As the high-pressure low-density polyethylene,
In addition to the ethylene homopolymer, a copolymer with another monomer such as an ethylene-vinyl acetate copolymer can be used. When using an ethylene-vinyl acetate copolymer, the repeating unit derived from vinyl acetate in the copolymer,
Usually, it is preferred that it is 20 wt% or less.

The polyethylene composition for a biaxially stretched film of the present invention can be used to produce a monolayer or multilayer biaxially stretched film by a simultaneous biaxial stretching method or a sequential biaxial stretching method.

The polyethylene composition for a biaxially stretched film according to the present invention is preferably 3 to 7 in the machine direction and the transverse direction.
It is preferable to produce a biaxially stretched film in the range of 2 times, more preferably 3 to 6 times.

The polyethylene composition for a biaxially stretched film of the present invention has a biaxial stretching temperature in the range of more than 85 ° C. and less than 125 ° C., particularly, in the simultaneous biaxial stretching method, the temperature exceeds 85 ° C.
Temperature below 90 ° C, in the sequential biaxial stretching method,
It is preferable to produce a biaxially stretched film at a temperature lower than 20 ° C. Further, the temperature range in which biaxial stretching can be performed is higher than 10 ° C., more preferably, higher than 15 ° C. and lower than 35 ° C., particularly in the simultaneous biaxial stretching method, higher than 15 ° C. and lower than 35 ° C., successively. In the biaxial stretching method, exceed 10 ° C and 25 ° C
It is preferable to produce a biaxially stretched film in a range of less than.

The (A) ethylene-α-olefin copolymer of the present invention, (B) polyethylene and / or (C)
Polyethylene composition for biaxially stretched film, depending on the application, higher fatty acids, erucamide, oleamide,
Higher aliphatic amides such as ethylenebisoleic acid amide and ethylenebiserucamide, lubricants and slip agents such as metal soaps and glycerin esters, natural silica, synthetic silica, talc, zeolite, PMMA fine particles, aluminosilicate, diatomaceous earth Antioxidants such as blocking agents, phenols, phosphorus, and BHT; ultraviolet absorbers such as benzophenone, benzotriazole, and HALS; aluminum hydroxide, magnesium hydroxide, phosphorus and halogen-based flame retardants, silica, and calcium carbonate ,
Inorganic and organic fillers such as barium sulfate, mica, and carbon black, azo-based, phthalocyanine-based, quinacridone-based, iron oxide, ultramarine blue and other pigments, antistatic agents, surfactants, and the like can be added.

A) ethylene-α-olefin copolymer,
(B) polyethylene and / or (C) 100 parts by weight of the polyethylene composition for a biaxially stretched film,
It is preferable to add 0.05 to 1 part by weight of the above anti-blocking agent and 0.05 to 0.5 part by weight of the slip agent because the hot slip coefficient becomes small.

Ethylene-α for the biaxially stretched film of the present invention
-The biaxially stretched film made of an olefin copolymer has a hot slip coefficient of 1.4 or less, more preferably 1.2 or less, particularly 1.0 or less as an upper limit, and 0.1 or more and 0.1 or less as a lower limit. It is preferably at least 2, especially at least 0.3.

If the hot-slip coefficient of the biaxially stretched film is larger than the above range, the slip properties between products immediately after the shrink tunnel or in a state where the film temperature is increased due to hot filling or the like are deteriorated, and troubles occur in a transfer line or the like. It is easy to get up.

The above-mentioned biaxially stretched film is preferably used as a film for packaging food such as confectionery or the like, or as an exterior film for containers such as cup ramen.

The biaxially stretched film is not limited to paper such as kraft paper, metallic thin films such as aluminum foil and copper foil, low density polyethylene, high density polyethylene, ethylene-α-olefin copolymer and other biaxially stretched films. It can be used as a multilayer film having two or more layers by being bonded to a polymer film such as polyolefin, polyamide, polyvinyl chloride, polyvinylidene chloride, polyamide, and polysulfone.

[0043]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The characteristic values were measured as follows.

Method for measuring properties of (A) ethylene-α-olefin copolymer, (B) polyethylene and (C) polyethylene composition for biaxially stretched film [1] Density: 190 according to JIS K7112
A strand obtained at the time of MFR measurement at a load of 2.16 kg at 100 ° C. was heat-treated at 100 ° C. for 1 hour, and a sample cooled slowly to room temperature over 1 hour was measured using a density gradient tube. [2] Melt flow rate (MFR _2.16 ): JIS
In accordance with K7210, 19
It was determined by measuring the weight of the resin extruded in a strand shape for 10 minutes at a load of 2.16 kg at 0 ° C. [3] Melt flow rate ratio (MFR _10.0 / MFR
_2.16 ): 10.0K in the same manner as in the above method [2].
It is a value obtained by dividing the resin weight (MFR _10.0 ) obtained by the g load by the resin weight (MFR _2.16 ) obtained in the above [2].

[4] Molecular weight distribution: The molecular weight distribution (Mw / Mn) of the ethylene-α-olefin copolymer composition was measured by gel permeation chromatography (GPC). The measurement method is shown below. (1) Measuring device: WATERS 150CV was used. (2) Measurement sample: The polymer was dissolved in a solvent (o-dichlorobenzene) at a temperature of 145 ° C and a concentration of 1 mg / ml. (3) Measurement of molecular weight distribution: Measurement sample of (2) above.
4 ml was injected into two GPC columns AT-806MS, and the solvent was o-dichlorobenzene, the temperature was 145 ° C., and 1.
Performed at a flow rate of 0 ml / min. 35 measured by GPC
Minutes. The polymer concentration in the solution separated by the GPC column was measured with a differential refractometer (RI). The molecular weight was converted using a polystyrene standard. (4) Data processing: Data processing is performed in VAX-STATI
ON3100 was used. G obtained by the above measurement (3)
When a baseline is drawn on the PC chromatogram, the area is integrated using data processing software attached to the apparatus, and the number average molecular weight (Mn), weight average molecular weight (Mw), Mw / Mn
Is automatically calculated. The GPC chromatogram was measured on the screen of the apparatus at a size of 125 mm per 20 minutes of measurement time on the horizontal axis and 13 mm per 20 with the total integrated elution amount set at 100 on the vertical axis.

[5] Flow index: Using a Toyo Seiki Capillograph, temperature 190 ° C., orifice L / D = 45 /
The shear rate at a shear stress of 2.4 × 10 ⁵ Pa under the condition of 1.5 was taken as the flow index.

Temperature rise elution fractionation of polymer (TREF)
The differential elution curve was measured by the following method. Cross sorter (Mitsubishi Chemical Corporation CF
Using CT150A), the measurement was performed according to the measurement method in the attached operation manual. This cross-separation apparatus includes a temperature rising elution fraction (TREF) for fractionating a sample using a difference in dissolution temperature (difference in crystallinity of a polymer), and a gel permeation chromatograph (TREF) for further fractionating a fractionated fraction by a molecular weight. GP
This is an apparatus combining C). (1) Measurement sample: The polymer was dissolved in a solvent (o-dichlorobenzene) at a temperature of 135 ° C and a concentration of 3 mg / ml, and injected into a sample loop of a measurement device. The following measurements were performed automatically according to the set conditions. (2) The measurement sample held in the sample loop is
Separation is performed using the temperature difference of dissolution, and a TREF column (inside diameter of 4 mm, length 1 packed with glass beads as an inert carrier)
0.5 ml into a 50 mm stainless steel column). (3) The measurement sample for injection was 1 in the TREF column.
It is cooled at a rate of 1 ° C./min from 35 ° C. to 0 ° C. and coated on an inert carrier (glass beads). (4) After the TREF column is maintained at a temperature of 0 ° C. for 30 minutes,
2 ml of the component dissolved at a temperature of 0 ° C. was transferred from the TREF column to the GPC column (Shodex) at a flow rate of 1 ml / min.
AT-806M / S × 3). (5) The concentration of the polymer in the solution fractionated by the molecular weight with the GPC column was measured by an infrared spectrophotometer (IR) (wavelength 3.
42 nm). (6) While fractionation based on molecular weight is being performed on the GPC column, the temperature of the TREF column is raised to the next elution temperature (10 ° C.) and maintained at that temperature for about 30 minutes. GPC
Is performed at 40 minute intervals. Thereafter, the elution temperature is increased stepwise in the following temperature order, and the samples separated at each elution temperature are subjected to molecular weight separation by GPC,
The measurement is repeated. Elution temperature order: 0 ° C, 10
° C, 20 ° C, 25 ° C, 30 ° C, 35 ° C, 40 ° C, 45 ° C
℃, 49 ℃, 52 ℃, 55 ℃, 58 ℃, 61 ℃, 64
° C, 67 ° C, 70 ° C, 73 ° C, 76 ° C, 79 ° C, 82
85 ° C, 88 ° C, 91 ° C, 95 ° C, 100 ° C, 10 ° C
5 ° C, 120 ° C, 135 ° C (28 fractions). (7) Data processing is automatically performed using data processing software attached to the device. The analysis order is [1] above (5),
A baseline is drawn on the GPC chromatogram at each elution temperature obtained in the measurement of (6), and the area is integrated.
[2] The integrated elution curve is calculated as the horizontal axis / elution temperature and vertical axis / integral value of GPC chromatogram. [3] The integrated elution curve is differentiated by temperature, and a differential elution curve is calculated and plotted as a calculated value of the horizontal axis / elution temperature and the vertical axis / differential.
[4] The calculation result is plotted. The size of the figure is 15 mm per 20 with the horizontal axis representing the elution temperature of 127.6 mm per 140 ° C. and the vertical axis representing the total integrated elution amount as 100.

(6) Standard deviation of elution amount with respect to elution temperature obtained by temperature rise elution fractionation (TREF) σ: The above-mentioned integrated elution curve (total integrated elution amount is set to 100) using data processing software attached to the apparatus. From 0 to 135
In the range of ° C, a derivative value (2 decimal places) in increments of 2 ° C is calculated. The standard deviation σ was calculated using the differential value.

Production of Biaxially Stretched Film and Evaluation of Obtained Film (1) Biaxial stretchability: Stretch moldability was evaluated by visual observation. ：: Stretchable without breaking, ×: Breakable and not stretchable The haze and hot slip coefficient were determined using the film stretched at the highest temperature within the range of stretchable temperature shown in Examples, Comparative Examples and Reference Examples. It was measured. (2) Hot Slip Coefficient: The stretched film was fixed on a hot plate at a temperature of 55 ° C., and a thread with a load of 100 g to which the stretched film was previously attached was placed thereon. The sled was placed on the hot plate and the sled was moved on the hot plate stretched film at a speed of 100 mm / min within 30 seconds. The force required to move the thread (gf) is divided by the load of the thread,
The value was used as the hot slip coefficient. . The sled was placed so that the stretched film attached to the sled was over the stretched film of the hotplate.

Table 1 shows the properties of the polyethylene polymer used.
And Table 2.

[0051]

[Table 1]

[0052]

[Table 2]

(Examples 1-3, Comparative Examples 1-3, Reference Example 1) Production of raw polyethylene film for producing biaxially stretched film The polymer composition shown in Table 3 and an antiblocking agent having an average particle size of 3 μm 5000pp of aluminosilicate
m, 1000 pp of erucamide as slip agent
m, die width 300 mm, chill roll (semi mud) 30 ° C., molding temperature 190-210 ° C., die temperature 24
An original polyethylene film for producing a biaxially stretched film having a thickness of 300 μm was produced by a 45 mmφT die molding machine at 0 ° C. and a take-up speed of 2 m / min. Formability of T-die molding machine during production of raw film (melt fracture)
Was visually evaluated, and the results are shown in Table 3. ○: good, ×: bad

(Examples 4 to 6, Comparative Examples 4 to 6, Reference Example 2) The above-mentioned 300 μm-thick polyethylene film raw material for producing a biaxially stretched film was stretched by using a biaxial stretching test machine manufactured by Iwamoto Seisakusho, Ltd. Simultaneous biaxial stretching was carried out under the conditions of MD 4 × TD 4 times, stretching speed 5 mm / sec, stretching temperature 80 to 140 ° C. (remaining heat 2 minutes). At this time, the stretchability was visually evaluated, and the resulting biaxially stretched film was measured for haze and hot slip coefficient. The results are shown in Table 4.

(Examples 7-9, Comparative Examples 7-9, Reference Example 3) The above-mentioned polyethylene film raw material for producing a biaxially stretched film having a thickness of 300 μm was stretched by using a biaxial stretching test machine manufactured by Iwamoto Seisakusho in Japan. MD 4 times × TD 4 times, stretching speed 5 mm / sec, stretching temperature 80 to 140 ° C (remaining heat 2 minutes), M
Five seconds after stretching in the D direction, biaxial stretching was successively performed under the conditions of stretching in the TD direction. At this time, the stretchability was visually evaluated,
Further, the obtained biaxially stretched film was measured for haze and hot slip coefficient, and the results are shown in Table 5.

[0056]

[Table 3]

[0057]

[Table 4]

[0058]

[Table 5]

[0059]

Industrial Applicability The polyethylene composition for a biaxially stretched film of the present invention is suitable for producing a biaxially stretched film having excellent stretchability, moldability, and productivity and small hot slip.

The biaxially stretched film comprising the polyethylene composition for a biaxially stretched film of the present invention has excellent hot slip.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 23:00 B29L 7:00

Claims (3)

[Claims] 1. An ethylene-α-olefin copolymer 2 prepared from a single-site catalyst having the following property (A):
A polyethylene composition for a biaxially stretched film having the following property (C), comprising 0 to 99% by weight and 80 to 1% by weight of a polyethylene having the following property (B). (A) Ethylene-α-olefin copolymer: (A-1) Density (d) = 0.880 to 0.950 (g /
^{cm 3) (A-2)} 190 ℃, melt flow rate at 2.16Kg load _{(MFR 2. 16) = 0.1~2.0 (} g / 1
0 min) (A-3) 190 ℃ , melt flow rate in 10.0Kg load (MFR _{10 .0)} and 190 ° C., 2.16 Kg
Ratio to the melt flow rate (MFR _2.16 ) under load (MFR _10.0 ) / (MFR _2.16 ) = 3.0 to 8.0 (A-4) Molecular weight distribution (Mw / Mn) = 2.0 to 4.0 ( A-5) Standard deviation of elution amount with respect to elution temperature obtained by temperature rise elution fractionation (TREF) σ ≦ 17 (A-6) Differential elution curve obtained by temperature rise elution fractionation (TREF) has two or more peaks (B) polyethylene: (B-1) density (d) = 0.900 to 0.960 (g /
^{cm 3) (B-2)} 190 ℃, melt flow rate at 2.16Kg load (MFR _{2. 16)} = 5 or more (g / 10 min) (C) biaxially oriented film for polyethylene composition: (C-1 ) Flow index = 45-1000 2. The polyethylene composition according to claim 1, wherein the biaxially stretched film has a hot slip coefficient of 1.4 or less. 3. A biaxially stretched film comprising the polyethylene composition for a biaxially stretched film according to claim 1.