JP2012097201A - Polyethylene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyethylene resin composition that is excellent in processability and is suitable for a film having high transparency, good openability and high tear strength.SOLUTION: The polyethylene resin composition [I] for a film is used, which includes [A] an ethylene/α-olefin copolymer satisfying the requirements of (a)-(e) as given below and [B] a high-density polyethylene satisfying the requirements of (f) and (g) as given below and has a ratio of [A]/[B] (weight ratio) of 99.5/0.5 to 80/20. The requirements are as follows: (a) the density is 890-940 kg/m; (b) the MFR is 0.1-10 g/10 min; (c) the Mw/Mn is 1.5-4; (d) the endothermic curve has substantially a single peak and the relationship between the temperature (Tm(°C)) at a peak position and the number of short chain branches (SCB) per 1,000 atoms of carbon satisfies Tm<-1.15×SCB+131: (e) the α-olefin has three or more carbons; (f) the density is 940-970 kg/m; and (g) the MFR is 3-50 g/10 min.

Description

  The present invention relates to a polyethylene resin composition suitable for a film having excellent processability, high transparency, good openability, and high tear strength.

  Linear low-density polyethylene polymer (LLDPE) is widely used as various film-forming resins because of its excellent moldability, strength, and heat seal characteristics. However, in recent years, film thickness reduction and weight reduction have been demanded from the viewpoints of carbon dioxide reduction, environmental considerations, labor load reduction, and material cost reduction. Since film thinning leads to a decrease in film strength, the raw material is required to have higher strength. Therefore, although a film was formed using an ethylene-α-olefin copolymer having a narrow molecular weight distribution and composition distribution due to a new catalyst, the motor load of the extruder is high, the skin is easily roughened, and it does not have a high crystal component. There was a problem that the opening of the film was bad. In order to improve the opening property, it is possible to take a method of blending a large amount of an antiblocking agent, but there are problems such as an increase in raw material costs and a tendency to occur in the eyes. On the other hand, Patent Document 1 and Patent Document 2 disclose techniques for blending high-density polyethylene with a specific ethylene-α-olefin copolymer, but generally use an inflation molding method and a cast molding method that are commercially implemented. When film-forming was used, there was a problem that the tear strength in the longitudinal direction of the film (the film flow direction during forming, hereinafter referred to as MD) was lowered.

JP 10-110068 A JP-A-8-291235

  The object of the present invention is to eliminate these disadvantages of the prior art, and it has good processability, the resulting film has high transparency, good openability, and is suitable for a film having high tear strength. The object is to provide a resin composition.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention incorporated a specific high-density polyethylene (hereinafter referred to as HDPE) into a specific ethylene / α-olefin copolymer [A]. Thus, a polyethylene resin composition suitable for an unprecedented film can be obtained, and the present invention has been completed.
That is, the present invention relates to an ethylene-α-olefin copolymer (A) that satisfies the following requirements (a) to (e) / high density polyethylene [B] = 99 that satisfies the following requirements (f) and (g): 5 / 0.5 to 80/20 (weight ratio), the polyethylene resin composition [I] for film, and the above-mentioned ethylene α-olefin copolymer [A] and high-density polyethylene [B The polyethylene resin composition for a film [I] / high pressure method low density polyethylene [C] satisfying the following requirements (h) to (J) = 100 / 0.1 to 100/10 (weight ratio) The present invention relates to a polyethylene resin composition [II] for film.
(A) Based on JIS K 7112: 1999, the measured density is 890 to 940 kg / m ^3.
(B) Melt flow rate (MFR) measured in accordance with JIS K 7210: 1999 under a load of 190 ° C. and 21.18 N is 0.1 to 10 g / 10 minutes (c) Weight average molecular weight (Mw) and number average Molecular weight (Mn) ratio (Mw / Mn) is 1.5-4
(D) In a differential scanning calorimeter, the endothermic curve obtained when melting at 200 ° C. for 5 minutes and then cooling to 30 ° C. at 10 ° C./min is raised at 10 ° C./min. It has a single peak, and the relationship between the temperature at the peak position (Tm (° C.)) and the number of short chain branches (SCB) per 1000 carbon atoms determined from the measurement of infrared absorption spectrum is expressed by the equation (1). Fulfill.
Tm <−1.15 × SCB + 131 (1)
(E) A copolymer of ethylene and an α-olefin having 3 or more carbon atoms.
(F) Based on JIS K 7112: 1999, the measured density is 940 to 970 kg / m ^3.
(G) Melt flow rate (MFR) measured under a load of 190 ° C. and 21.18 N measured in accordance with JIS K 7210: 1999 is 3 to 50 g / 10 min.
(H) The measured density is 915 to 935 kg / m ^{3 based on} JIS K 7112: 1999.
(I) The melt flow rate (MFR) measured under a load of 190 ° C. and 21.18 N measured in accordance with JIS K 7210: 1999 is in the range of 0.1 to 10 g / 10 min.
(J) Using the melt indexer used in JIS K 7210, dividing the diameter (D) of the extruded strand at a temperature of 235 ° C. and an extrusion rate of 3 g / min by the orifice diameter (D ₀ ) of the melt indexer The obtained swell ratio (SR) is 1.8 to 3.0.

  The present invention is described in detail below.

The ethylene-α-olefin copolymer [A] constituting the polyethylene resin composition of the present invention has (a) a density of 890 to 940 kg / m ³ and (b) a melt flow rate (MFR) of 0.1 to 10 g. / 10 minutes, (c) Mw / Mn is 1.5 to 4, and (d) In a differential scanning calorimeter, it is melted at 200 ° C. for 5 minutes and then cooled to 30 ° C. at 10 ° C./minute. The endothermic curve obtained when the temperature is raised at 0 ° C./min has a substantially single peak, and the relationship between Tm (° C.) and SCB satisfies the relationship represented by the above formula (1), and (e) ethylene And an α-olefin copolymer having 3 or more carbon atoms, and an ethylene-α-olefin copolymer satisfying the respective requirements.

Here, when the density of the ethylene-α-olefin copolymer exceeds 940 kg / m ³ , impact resistance strength and tear strength are low. On the other hand, when the density is less than 890 kg / m ³ , the obtained polyethylene film has a high self-adhesiveness and has a problem that it is difficult to improve the opening property of the film. The density referred to in the present invention is based on JIS K 7112: 1999, and can be measured with a density gradient tube that is immersed in hot water at 100 ° C. for 1 hour, cooled to room temperature, and maintained at 23 ° C.

  In addition, when the MFR of the ethylene-α-olefin copolymer is less than 0.1 g / 10 min, the melt shear viscosity is high, so that the load on the extruder when forming a polyethylene film is increased, and the drawdown is reduced. The productivity is also inferior and the productivity is inferior. On the other hand, when it is larger than 10 g / 10 minutes, the melt tension is small and the film formation stability is poor, and thus it is difficult to stably obtain a polyethylene film. Even if a polyethylene film is obtained, its mechanical strength is low. In addition, MFR as used in this invention is based on JISK7210: 1999, and is measured on the conditions of 190 degreeC and 21.18N load.

  When the Mw / Mn of the ethylene-α-olefin copolymer is less than 1.5, the shear stress at the time of polyethylene film molding processing becomes large, the load on the extruder is large, and the productivity is inferior. Moreover, the obtained polyethylene film has poor skin and inferior quality. On the other hand, when Mw / Mn exceeds 4, the resulting polyethylene film is inferior in impact resistance and has a sticky surface. In addition, Mw / Mn as used in the field of this invention is computable from the ratio of Mw and Mn measured as a standard polystyrene conversion value by gel permeation chromatography (henceforth GPC).

  When the ethylene-α-olefin copolymer does not satisfy the above formula (1), the copolymerization distribution of ethylene and α-olefin becomes wide, and the polyethylene film is inferior in impact resistance and transparency. At the same time, the surface becomes sticky. Further, this ethylene / α-olefin copolymer is such that Tm (° C.) and the number of short chain branches per 1000 carbon atoms (SCB) obtained from the measurement of infrared absorption spectrum satisfy the relationship of the formula (1). It is.

  The ethylene-α-olefin copolymer is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms. Examples of the α-olefin having 3 or more carbon atoms include propylene, butene-1, pentene-1, and hexene-1. Octene-1 and the like.

  As the ethylene-α-olefin copolymer [A] constituting the polyethylene resin composition of the present invention, any ethylene-α-olefin copolymer satisfying the above requirements (a) to (e) may be used. For example, a metallocene polymerization catalyst can be used as a production method by copolymerizing ethylene and an α-olefin.

The high density polyethylene (HDPE) [B] constituting the polyethylene resin copolymer of the present invention has the requirements that (f) density is 940 to 970 kg / m ³ , and (g) MFR is ³ to 50 g / 10 min. Any high-density polyethylene that satisfies these requirements can be used, and can be produced by a coordinated anionic polymerization method using a conventionally known Ziegler-Natta polymerization catalyst. For example, (trade name) Nipolon Hard (manufactured by Tosoh Corporation) and the like can be mentioned.

The density of the high-density polyethylene [B] is 940 to 970 kg / m ³ because the polyethylene film has a particularly good opening property. Here, when a density is less than 940 kg / m < ³ >, the opening property of the obtained polyethylene film is not favorable. On the other hand, it is actually difficult to obtain high-density polyethylene having a density exceeding 970 kg / m ³ . The density can be measured by the method described above.

  Moreover, MFR of a high density polyethylene is 3-50 g / 10min. When the MFR of the high-density polyethylene is less than 3 g / 10 min, when the composition with the ethylene-α-olefin copolymer is formed into a film using a commercially-used inflation molding method or cast molding method, Elmendorf The tear strength in the machine direction (film flow direction during molding, hereinafter referred to as MD) required by the tearing method is lower than that of an ethylene / α-olefin copolymer not blended with HDPE. On the other hand, when the MFR is larger than 50 g / 10 minutes, it is difficult to stably obtain a polyethylene film because the melt tension is low and the film formation stability is poor. Also, if the MFR is 10 to 30 g / 10 min, the balance between the transparency of the film formed from the composition obtained by blending the ethylene / α-olefin copolymer and HDPE and the tear strength of the MD is good. Further preferred. MFR can be measured by the method described above.

  The polyethylene resin composition [1] of the present invention comprises the ethylene-α-olefin copolymer [A] / the HDPE [B] (weight ratio) in the range of 99.5 / 0.5 to 80/20. It is. Here, when the ethylene-α-olefin copolymer [A] / HDPE [B] is larger than 99.5 / 0.5 (weight ratio), the surface of the film formed from the polyethylene resin composition [1] is very For example, the opening property of a film obtained by folding a tube obtained by inflation molding or the opening property of a bag obtained by using an existing method such as heat sealing the film becomes poor. In order to solve this problem, it is necessary to blend a large amount of an antiblocking agent such as diatomaceous earth, zeolite, talc, or a polymer compatible with ethylene / α-olefin copolymer into the polyethylene resin composition. On the other hand, when the ethylene-α-olefin copolymer [A] / HDPE [B] is smaller than 80/20, the transparency of the film is poor.

Since the polyethylene resin composition of the present invention has excellent transparency of the molded film, the polyethylene resin composition [I] / high-pressure low-density polyethylene that satisfies the following requirements (h) to (k) [ C] (weight ratio) is preferably a polyethylene resin composition [II] having a ratio of 100 / 0.1 to 100/10.
(H) The measured density is 915 to 935 kg / m ^{3 based on} JIS K 7112: 1999.
(I) A melt flow rate (MFR) measured under a load of 190 ° C. and 21.18 N measured in accordance with JIS K 7210: 1999 is 0.1 to 10 g / 10 min.
(J) Using the melt indexer used in JIS K 7210, dividing the diameter (D) of the extruded strand at a temperature of 235 ° C. and an extrusion rate of 3 g / min by the orifice diameter (D ₀ ) of the melt indexer The obtained swell ratio (SR) is 1.8 to 3.0.

The high pressure method low density polyethylene (LDPE) [C] used in the present invention has (h) density of 915 to 935 kg / m ³ , (i) MFR of 0.1 to 10 g / 10 min, and (j) SR of 1 .8 to 3.0, high pressure method low density polyethylene satisfying the requirements, and any high pressure method low density polyethylene satisfying these requirements can be used. For example, (trade name) Petrocene (manufactured by Tosoh Corporation) can be mentioned.

LDPE [C] preferably has a density in the range of 915 to 930 kg / m ³ . When the density is within this range, the resulting film has excellent opening properties and a great effect of improving transparency. The density can be measured by the method described above.

  The MFR of LDPE [C] is preferably in the range of 0.1 to 10 g / 10 minutes. When the MFR is in this range, the film obtained by molding has less fish eyes because of excellent dispersibility when blended with the polyethylene composition [I]. Great transparency improvement effect.

  Moreover, it is preferable that SR of LDPE [C] is the range of 1.8-3.0. When SR is 1.8 or more, the transparency improvement effect of the obtained film is high, while it is actually difficult to obtain a high-pressure method low-density polyethylene with SR exceeding 3. LDPE [C] with SR of 2.0 or more has a particularly great effect of improving transparency, and the blending ratio of LDPE [C] can be reduced. Therefore, the tear strength of the molded film caused by blending LDPE [C] A decrease in mechanical strength such as impact strength is small, which is particularly preferable.

  The polyethylene resin composition [II] of the present invention has a polyethylene film composition [I] / LDPE [C] = 100 / 0.1 to 100/10 (weight ratio) in the range of the molded film. It is preferable because it has good transparency and high mechanical strength. The polyethylene resin composition [I] / LDPE [C] = 100 / 0.1 to 100/2 (weight ratio) is a film obtained by molding by blending LDPE (C). The decrease in mechanical strength such as tear strength and impact strength is particularly preferable.

  As the ethylene-α-olefin copolymer [A], HDPE [B] and LDPE [C], one kind or a mixture of two or more kinds is used.

  The polyethylene resin compositions [I] and [II] of the present invention may be added to polyolefin resins such as antioxidants, weathering stabilizers, antistatic agents, lubricants, blocking agents, etc. as necessary. An additive such as a hindered phenol, phosphorus, sulfur, hindered amine, vitamin E, etc .; a weathering stabilizer such as a hindered amine weathering stabilizer; benzotriazole UV absorbers, benzophenone UV absorbers, etc .; saturated fatty acid amide, unsaturated fatty acid amide, ethylene bis saturated fatty acid amide, ethylene bis unsaturated fatty acid amide, N-substituted bis saturated fatty acid amide, N-substituted non-substituted Lubricants such as saturated fatty acid amides; acid clay, diatomaceous earth, talc, zeolite, aluminosilicate, kaolin, polyester Antiblocking agents such as polymers incompatible with lens; Antistatic agents such as fatty acid glycerides, fatty acid amines, higher alcohols and polyhydric alcohols; Metal soaps such as calcium stearate and lithium stearate; Acid supplements such as hydrotalcite , Etc.

  As a method for producing the polyethylene resin composition [I] of the present invention, dry blending of the ethylene-α-olefin copolymer (A) pellets and the high-density polyethylene (B) pellets, or single screw extrusion Examples thereof include a melt kneading method using a melt kneader such as a machine, a twin screw extruder, a kneader, a Banbury, a roll, etc. In particular, since the quality of the film formed from the polyethylene resin composition is stabilized, melt kneading is preferred.

  The polyethylene resin composition [II] may be a dry blend of the polyethylene resin composition [I] and LDPE [C], but is melt-kneaded with a single-screw or twin-screw extruder, a kneader, a banbury, a roll, or the like. The one is preferable because the quality of the formed film is stable. Further, at the time of producing the polyethylene resin composition [II], the ethylene-α-olefin copolymer [A], HDPE [B] and LDPE [C] may be dry blended at the same time, and melt kneading using the above method. You may do it.

  As a method for producing the films of the polyethylene resin compositions [I] and [II] of the present invention, any method can be used as long as the film can be formed. For example, it can be produced by an air-cooled inflation method, a water-cooled inflation method, a T-die cast method, or the like. Moreover, it can also be used as a single layer of a multilayer film formed by a coextrusion method, an extrusion lamination method, a dry lamination method, or the like. These films can be widely used for agricultural house covering materials, packaging films, liquid filling films, and the like.

  The polyethylene resin composition of the present invention is suitable for a film because it has good processability, and the resulting film has high transparency, good openability, and high tear strength.

It is the figure which showed the relationship of (1) Formula with the ethylene-alpha-olefin copolymer [A] of this invention, and commercially available resin.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
[Production of ethylene-α-olefin copolymer]
The ethylene-α-olefin copolymers [A1], [A2] and [A3] used in Examples and Comparative Examples were produced by the following method.

The polymerization operation, reaction and solvent purification were all performed under an inert gas atmosphere. Moreover, the solvent etc. which were used for the reaction were all purified, dried and deoxygenated by a known method in advance. Furthermore, the compound used for the reaction was synthesized and identified by a known method.
<Preparation of catalyst (A)>
Under a nitrogen atmosphere, diethylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride is added to 10 mol / zirconium atom by diluting triethylaluminum to 4.5 mol / aluminum atom in 4.6 liters of dehydrated heptane. By adding 300 g of N, N-dimethyl-octadecylammonium hydrochloride-modified montmorillonite to the resulting red suspension for reaction, and adding an aliphatic saturated hydrocarbon solvent (IP Solvent 2835 (manufactured by Idemitsu Petrochemical Co., Ltd.)). A catalyst was prepared. (Zirconium concentration 0.5 mmol / L).
<Preparation of catalyst (B)>
Catalyst (A) except that diphenylmethylene (1-indenyl) (2,7-di-t-butyl-9-fluorenyl) zirconium dichloride was used instead of diphenylmethylene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride. ) To obtain a catalyst (B) (zirconium concentration of 0.5 mmol / L).
<Polymerization>
Polymerization was carried out using a tank reactor.

  The polymerization method of the ethylene-α-olefin copolymer [A1] is as follows. Ethylene, 1-hexene and ethane were continuously injected into the reactor, and the total pressure was set to 90 MPa and the 1-hexene concentration was set to 16 mol%. The reactor was then stirred at 1500 rpm.

Then, the catalyst (A) and the catalyst (B) were continuously supplied from the supply port of the reactor, and polymerization was performed so that the average temperature was maintained at 209 ° C. As a result, an ethylene-hexene-1 copolymer [A1] having an MFR of 1.0 g / min and a density of 920 kg / m ³ was obtained.

  The polymerization method of the ethylene-α-olefin copolymer [A2] is as follows. Ethylene, 1-hexene and ethane were continuously injected into the reactor, and the total pressure was set to 90 MPa and the 1-hexene concentration was set to 21 mol%. The reactor was then stirred at 1500 rpm.

Then, the catalyst (A) and the catalyst (B) were continuously supplied from the supply port of the reactor, and polymerization was performed so that the average temperature was kept at 204 ° C. As a result, an ethylene-hexene-1 copolymer [A2] having an MFR of 1.0 g / min and a density of 915 kg / m ³ was obtained.

  The polymerization method of the ethylene-α-olefin copolymer [A3] is as follows. Ethylene, 1-hexene and ethane were continuously injected into the reactor, and the total pressure was set to 90 MPa and the 1-hexene concentration was set to 26 mol%. The reactor was then stirred at 1500 rpm.

Then, the catalyst (A) and the catalyst (B) were continuously supplied from the supply port of the reactor, and polymerization was performed so that the average temperature was maintained at 198 ° C. As a result, an ethylene-hexene-1 copolymer [A3] having an MFR of 2.0 g / min and a density of 910 kg / m ³ was obtained.

  The polymerization method of the ethylene-α-olefin copolymer [A4] is as follows. Ethylene, 1-hexene and ethane were continuously injected into the reactor, and the total pressure was set to 83 MPa and the 1-hexene concentration was set to 27 mol%. The reactor was then stirred at 1500 rpm.

Then, the catalyst (A) and the catalyst (B) were continuously supplied from the supply port of the reactor, and polymerization was performed so that the average temperature was maintained at 227 ° C. As a result, an ethylene-hexene-1 copolymer [A4] having an MFR of 4.0 g / min and a density of 910 kg / m ³ was obtained.

  The polymerization method of the ethylene-α-olefin copolymer [A5] is as follows. Ethylene, 1-hexene and ethane were continuously injected into the reactor, and the total pressure was set to 88 MPa and the 1-hexene concentration was set to 15 mol%. The reactor was then stirred at 1500 rpm.

Then, the catalyst (A) and the catalyst (B) were continuously supplied from the supply port of the reactor, and polymerization was performed so that the average temperature was maintained at 216 ° C. As a result, an ethylene-hexene-1 copolymer [A5] having an MFR of 4.0 g / min and a density of 923 kg / m ³ was obtained.
[Granulation of ethylene-α-olefin copolymer]
The copolymer used in the Examples and Comparative Examples was prepared by using a phenolic antioxidant (IRGANOX 1076, manufactured by Ciba Specialty Chemicals) as an antioxidant, and 800 ppm of a phosphorus antioxidant (IRGAFOS 168, manufactured by Ciba Specialty Chemicals), a steer. It is obtained by adding 750 ppm calcium phosphate (manufactured by Tamnan Chemical Co., Ltd., calcium stearate) and 500 ppm hydrotalcite (manufactured by Kyowa Chemical Co., Ltd., DHT-4A) and melt granulating with a single screw extruder.
[Production of high-density polyethylene]
As HDPE [B] in Examples and Comparative Examples, Tosoh Corporation high density polyethylene (trade name: Nipolon Hard) was used.
[Production of low density polyethylene]
As LDPE [C] in Examples and Comparative Examples, low density polyethylene (trade name: Petrocene) manufactured by Tosoh Corporation was used.
[Measurement method of resin properties]
Various physical properties of the ethylene-α-olefin copolymer, high-density polyethylene, and low-density polyethylene used in Examples and Comparative Examples were measured by the following methods.
<density>
According to JIS K 7112, the density of what was immersed in hot water at 100 ° C. for 1 hour and then allowed to cool at room temperature was measured with a density gradient tube maintained at 23 ° C.
<MFR melt flow rate (MFR)>
According to JIS K 7210, measurement was performed under a load of 190 ° C. and 21.18 N.
<Mw / Mn>
The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured using gel polystyrene by gel permeation chromatography (hereinafter GPC). Measuring device: HLC-8121GPC / HT (RI), column: TSK gelGMHHhr-H (20) × 3, measuring solvent: 1,2,4-trichlorobenzene, sample concentration: 0.1 mg / ml, measuring temperature: 140 ° C, flow rate: 1.0 ml / min.
<Melting point>
It measured using the differential scanning calorimeter [Seiko Instruments Co., Ltd. product, RDC220]. The temperature at the maximum peak position of the endothermic curve obtained when the sample was melted at 200 ° C. for 5 minutes in the apparatus and then cooled to 30 ° C. at 10 ° C./min was again raised at 10 ° C./min. The melting point.
<Short-chain branch number (SCB)>
The number of short chain branches (SCB) in the molecular chain was obtained by cooling the resin pellet with ice water using a Fourier transform infrared absorption spectrum apparatus [Perkin Elmer Co., Ltd., SPECTRUM ONE], followed by cooling with ice water. The intensity of the absorption band corresponding to the bending vibration of the methyl group located at 1378 cm ^{−1 of a} 0.1 mm sample was measured, and calculated from a calibration curve prepared with a known material.
<Swell ratio>
Using the melt indexer used in JIS K 7210, the diameter (D) of the strand extruded at a temperature of 235 ° C. and an extrusion rate of 3 g / min was divided by the orifice diameter (D ₀ ) of the melt indexer.
[Method for measuring film properties]
<Haze value>
Based on ASTM D1003, the haze value (%) of the film was measured using a haze meter (manufactured by Nippon Denshoku Co., Ltd., model NDH-20D).
<Elmendorf tear strength (MD)>
Measured based on JIS K 7128-2: 1998 (Elmendorf tear method).
<Openness>
When the tube-like film obtained by inflation molding is cut into a length of 1 m, the tube is cut along the folds on one side, and both ends of the cut film are lifted by hand. The case where the film was not opened was marked as x, and the middle was marked as Δ.

Example 1
It is a composition of ethylene-hexene-1 copolymer [A1] / Nipolon Hard 2000 = 95/5 (weight ratio) polymerized by the polymerization method. [A1] has a density of 920 kg / m ³ , MFR of 1.0 g / 10 min, Tm of 117 ° C., Mw / Mn of 2.3, and SCB of 8.7 / 1000C. Nipolon Hard 2000 has a density of 960 kg / m ³ and an MFR of 15 g / 10 min. The composition of [A1] and Nipolon Hard 2000 was obtained by dry blending of pellets. The film was obtained using an inflation molding apparatus (extruder cylinder diameter 50 mmφ, die diameter 75 mmφ, lip clearance 2 mm) manufactured by Plako Corporation. Film forming conditions were an extruder and a die set temperature of 190 ° C., a take-up speed of 14 m / min, a film thickness of 0.05 mm, and a tube folding diameter of 240 mm. As a result, a film having good openness, transparency, and strength was obtained with an openness of ◯, a haze value of 11.8%, and an Elmendorf tear strength (MD) of 113 kN / m.

Example 2
A film was obtained in the same manner as in Example 1, except that the composition was ethylene-hexene-1 copolymer [A1] / Nipolon Hard 2000 = 90/10 (weight ratio) polymerized by the above polymerization method. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 13.9%, and an Elmendorf tear strength (MD) of 111 kN / m.

Comparative Example 1
A film was obtained in the same manner as in Example 1 except that the ethylene-hexene-1 copolymer [A1] polymerized by the polymerization method was a 100% composition. As a result, the openability was Δ and sufficient openability was not obtained.

Comparative Example 2
It is a composition of ethylene-hexene-1 copolymer [A1] / Nipolon hard 8022 = 90/10 (weight ratio) polymerized by the polymerization method. Nipolon Hard 8022 has a density of 958 kg / m ³ and an MFR of 0.35 g / 10 min, which is below the MFR range of the high density polyethylene of claim 1. Otherwise, a film was obtained in the same manner as in Example 1. As a result, the film was a film having good openness and transparency with a good openness and a haze value of 10.3%, but the Elmendorf tear strength (MD) was 96 kN / m, as compared with Examples 1 and 2. It was inferior.

Comparative Example 3
Ethylene-octene-1 copolymer trade name ELITE 5400G manufactured by Dow Co. polymerized with a metallocene catalyst is a 100% composition. A film was obtained in the same manner as in Example 1. ELITE5400G has a density of 0.916 kg / m ³ , MFR of 1.0 g / 10 min, Tm of 121 ° C., Mw / Mn of 3.7, and SCB of 12.7 / 1000C. Here, Mw / Mn and Tm of ELITE5400G deviate from the relationship between Tm and SCB defined by the definition of Mw / Mn in claim 1 and equation (1) in claim 1. Others obtained the film by the same method as in Example 1. As a result, the openability was good, but the haze value was 15.2%, the Elmendorf tear strength was (MD) 82 kN / m, and the transparency and strength were good. Both were inferior to the examples.

Example 3
It is a composition of ethylene-hexene-1 copolymer [A1] / Nipolon hard 4000 / Petrocene 360 = 90/10 (weight ratio) polymerized by the above polymerization method. Nipolon Hard 4000 has a density of 965 kg / m ³ and an MFR of 5 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openness of ○, a haze value of 14.2%, and an Elmendorf tear strength (MD) of 110 kN / m.

Example 4
A film was obtained in the same manner as in Example 1, except that the composition was ethylene-hexene-1 copolymer [A2] / Nipolon Hard 2000 = 90/10 (weight ratio) polymerized by the above polymerization method. [A2] has a density of 915 kg / m ³ , MFR of 1.0 g / 10 min, Tm of 113 ° C., Mw / Mn of 2.3, and SCB of 11.3 / 1000C. As a result, a film having good openness, transparency, and strength was obtained with an openness of ◯, a haze value of 8.2%, and an Elmendorf tear strength (MD) of 109 kN / m.

Example 5
The composition 100 was blended so that the ethylene-hexene-1 copolymer [A2] / Nipolon Hard 2000 = 90/10 (weight ratio) polymerized by the polymerization method was melt-kneaded using a short-shaft extruder. On the other hand, Petrocene 360 was dry blended at a ratio of 2 to obtain a composition. Petrocene 360 has a density of 919 kg / m ³ , an MFR of 1.6 g / 10 min, and a swell ratio of 2.41. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with openness of ◯, haze value of 6.6%, and Elmendorf tear strength (MD) of 99 kN / m.

Comparative Example 4
A film was obtained in the same manner as in Example 1 except that the ethylene-hexene-1 copolymer [A2] polymerized by the polymerization method was a 100% composition. As a result, the opening property was x and sufficient opening property was not obtained.

Example 6
The ethylene-hexene-1 copolymer polymerized by the polymerization method [A3] / Nipolon Hard 4000 / Petrocene 360 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . [A3] has a density of 910 kg / m ³ , MFR of 2.0 g / 10 min, Tm of 107 ° C., Mw / Mn of 2.3, and SCB of 16.4 / 1000C. Nipolon Hard 4000 has a density of 965 kg / m ³ and an MFR of 5 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 7.4%, and an Elmendorf tear strength (MD) of 143 kN / m.

Example 7
The ethylene-hexene-1 copolymer polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 360 = 95/5/1 (weight ratio) was blended and dry blended to obtain a composition. . A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency and strength was obtained with an openness of ◯, a haze value of 3.2%, and an Elmendorf tear strength (MD) of 132 kN / m.

Example 8
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 360 = 95/5/2 (weight ratio) was blended and dry blended to obtain a composition. . A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 3.0%, and an Elmendorf tear strength (MD) of 132 kN / m.

Example 9
The ethylene-hexene-1 copolymer polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 360 = 95/5/5 (weight ratio) was blended and dry blended to obtain a composition. . A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 2.4%, and an Elmendorf tear strength (MD) of 115 kN / m.

Example 10
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 360 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 5.1%, and an Elmendorf tear strength (MD) of 145 kN / m.

Example 11
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolon hard 1200 / Petrocene 360 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . Nipolon Hard 1200 has a density of 952 kg / m ³ and an MFR of 21 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 3.9%, and an Elmendorf tear strength (MD) of 135 kN / m.

Example 12
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [N3] / Nipolon Hard 0S02F / Petrocene 360 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. Nipolon Hard 0S02F has a density of 957 kg / m ³ and an MFR of 30 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 6.0%, and an Elmendorf tear strength (MD) of 139 kN / m.

Example 13
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 172 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . Petrocene 172 has a density of 920 kg / m ³ , MFR of 0.3 g / 10 min, and a swell ratio of 2.02. A film was obtained by the same method as in Example 1 using the composition. As a result, a film having good openness, transparency, and strength was obtained with an openability of ◯, a haze value of 5.9%, and an Elmendorf tear strength (MD) of 134 kN / m.

Comparative Example 5
A film was obtained in the same manner as in Example 1 except that the ethylene-hexene-1 copolymer [A2] was polymerized by the polymerization method. As a result, the opening property was x and sufficient opening property was not obtained.

Comparative Example 6
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolone LM65 / Petrocene 360 was blended so as to be 90/10/2 (weight ratio) and dry blended to obtain a composition. . Nipolon LM65 has a density of 920 kg / m ³ and an MFR of 20 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, the opening property was x and sufficient opening property was not obtained.

Comparative Example 7
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolone LM70 / Petrocene 360 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . Nipolon LM70 has a density of 936 kg / m ³ and an MFR of 20 g / 10 min. A film was obtained by the same method as in Example 1 using the composition. As a result, the opening property was x and sufficient opening property was not obtained.

Comparative Example 8
The ethylene-hexene-1 copolymer [A3] polymerized by the above polymerization method [A3] / Nipolon Hard 2000 / Petrocene 183 = 90/10/2 (weight ratio) was blended and dry blended to obtain a composition. . Petrocene 183 has a density of 924 kg / m ³ , an MFR of 2.0 g / 10 min, and a swell ratio of 1.73. A film was obtained by the same method as in Example 1 using the composition. As a result, the film has a good opening property and strength, with an opening property of ◯, a haze value of 9.2%, and an Elmendorf tear strength (MD) of 132 kN / m. Transparency was inferior to that of the film. Table 1 shows the characteristics of the ethylene-hexene-1 copolymer [A] used in Examples and Comparative Examples.

また、（１）式の技術的意義を示すために図１に示した（１）式の関係を満たさない樹脂（市販品）樹脂の物性値を表２に示す。

Table 2 shows physical property values of resins (commercially available) resins that do not satisfy the relationship of the formula (1) shown in FIG. 1 in order to show the technical significance of the formula (1).

表３に実施例および比較例中に用いたＨＤＰＥの特徴を示した。

Table 3 shows the characteristics of HDPE used in Examples and Comparative Examples.

表４に実施例および比較例中に用いたＬＤＰＥの特徴を示した。

Table 4 shows the characteristics of LDPE used in Examples and Comparative Examples.

表５に実施例および比較例中に用いたＬＤＰＥの特徴を示した。

Table 5 shows the characteristics of the LDPE used in the examples and comparative examples.

表６に実施例および比較例に示したインフレーション成形によって得たフィルムの物性に関して、エチレン−αオレフィン共重合体の特徴の違い、ＨＤＰＥ［Ｂ］の配合比の違い、およびＨＤＰＥの特徴の違いによるフィルム物性への影響を示した。まず、実施例１、２および３は、エチレン−αオレフィン共重合体として請求項１の要件を満たす［Ａ１］を用い、ＨＤＰＥとして請求項１の要件を満たすニポロンハード２０００および４０００を用いた。それぞれ［Ａ１］／ＨＤＰＥ＝９５／５ないし９０／１０（重量比）で配合されているから、ＨＤＰＥ［Ｂ］を配合していない比較例１に比較し開口性が優れる。また、実施例２および３は、ＨＤＰＥ［Ｂ］のＭＦＲが請求項１の要件である３〜５０ｇ／１０分の範囲内であるから、配合比率が［Ａ１］／ＨＤＰＥ＝９０／１０（重量比）と同様でありながら、ＨＤＰＥとしてＭＦＲが０．３５ｇ／１０分と請求項１に定める範囲より小さいニポロンハード８０２２を用いた比較例２に比較して、エルメンドルフ引裂強度（ＭＤ）の値が高い。一方で、比較例３に用いたＥＬＩＴＥ５４００Ｇは請求項１の（１）式を満たさないのでヘーズ値が高く、エルメンドルフ引裂強度（ＭＤ）の値が低い。

Regarding the physical properties of the films obtained by the inflation molding shown in Table 6 in Examples and Comparative Examples, due to the difference in the characteristics of the ethylene-α-olefin copolymer, the mixing ratio of HDPE [B], and the characteristics of the HDPE The effect on film properties was shown. First, Examples 1, 2, and 3 used [A1] satisfying the requirement of claim 1 as the ethylene-α-olefin copolymer, and Nipolon Hard 2000 and 4000 satisfying the requirement of claim 1 as HDPE. Since each of them is blended at [A1] / HDPE = 95/5 to 90/10 (weight ratio), the openability is excellent as compared with Comparative Example 1 in which HDPE [B] is not blended. In Examples 2 and 3, since the MFR of HDPE [B] is within the range of 3 to 50 g / 10 min which is the requirement of claim 1, the blending ratio is [A1] / HDPE = 90/10 (weight) The ratio of Elmendorf tear strength (MD) is higher than that of Comparative Example 2 using Nipolon Hard 8022 having an MFR of 0.35 g / 10 min as HDPE, which is smaller than the range defined in claim 1. . On the other hand, ELITE 5400G used in Comparative Example 3 does not satisfy the formula (1) of claim 1 and therefore has a high haze value and a low Elmendorf tear strength (MD) value.

表７に実施例および比較例に示したインフレーション成形によって得たフィルムの物性に関して、エチレン−αオレフィン共重合体に請求項１の要件を満たしつつ、表６中の［Ａ１］とは異なる［Ａ２］を用い、請求項１の要件を満たすＨＤＰＥであるニポロンハード２０００の配合の効果、および請求項２の要件を満たすＬＤＰＥであるペトロセン３６０の配合の効果を示した。実施例３は［Ａ２］／ニポロンハード２０００＝９０／１０（重量比）だから、ＨＤＰＥ［Ｂ］の配合されていない比較例４に比較し、開口性に優れる。実施例４は［Ａ２］／ニポロンハード２０００／ペトロセン３６０＝９０／１０／２（重量比）だから、開口性に優れ、ヘーズの値が低いので透明性が良好、さらにエルメンドルフ引裂強度（ＭＤ）が高いから引裂強度が良好である。

Regarding the physical properties of the films obtained by the inflation molding shown in Table 7 in Examples and Comparative Examples, the ethylene-α-olefin copolymer satisfies the requirements of claim 1 and is different from [A1] in Table 6 [A2]. ], The effect of blending Nipolon Hard 2000 which is HDPE satisfying the requirement of claim 1 and the effect of blending Petrocene 360 which is LDPE satisfying the requirement of claim 2 were shown. Since Example 3 is [A2] / Nipolon Hard 2000 = 90/10 (weight ratio), compared with Comparative Example 4 in which HDPE [B] is not blended, the opening property is excellent. Since Example 4 is [A2] / Nipolon Hard 2000 / Petrocene 360 = 90/10/2 (weight ratio), it has excellent opening properties, low haze value, good transparency, and high Elmendorf tear strength (MD). Therefore, the tear strength is good.

表８にはエチレン−αオレフィン共重合体に請求項１の要件を満たした［Ａ３］を用いた実施例５〜１３の配合とフィルム物性を示した。実施例５〜１３の配合に用いたエチレン−αオレフィン共重合体、ＨＤＰＥ、ＬＤＰＥおよびその配合比率はいずれも請求項１および請求項２の要件を満たすので、開口性に優れ、ヘーズ値が低いから透明性に優れ、かつエルメンドルフ引裂強度（ＭＤ）が高いから引裂強度が良好である。

Table 8 shows the composition and film properties of Examples 5 to 13 using [A3] that satisfies the requirements of claim 1 for the ethylene-α-olefin copolymer. Since the ethylene-α olefin copolymer, HDPE, LDPE and the blending ratio thereof used in the blending of Examples 5 to 13 all satisfy the requirements of Claims 1 and 2, they have excellent opening properties and low haze values. Therefore, the tear strength is good because of excellent transparency and high Elmendorf tear strength (MD).

表９にはエチレン−αオレフィン共重合体に請求項１の要件を満たした［Ａ３］を用いた比較例５〜８の配合とフィルム物性を示した。比較例５は［Ａ３］にＨＤＰＥが配合されていないから開口性に劣る。比較例６と比較例７にはそれぞれＨＤＰＥの代わりとして密度が請求項１の規定する範囲より低いニポロン−Ｌ Ｍ６５およびＭ７５を用いた。その結果、フィルムの開口性は劣るものであった。また、比較例８はＳＲが請求項２の規定する範囲より低いペトロセン１８３を用いているので、表８中の実施例５〜１３に比較しヘーズが高いから、ＬＤＰＥ配合による透明性の改良が不十分である。

Table 9 shows the composition and film physical properties of Comparative Examples 5 to 8 using [A3] satisfying the requirements of claim 1 for the ethylene-α-olefin copolymer. Comparative Example 5 is inferior in opening properties because HDPE is not blended in [A3]. In Comparative Examples 6 and 7, Nipolon-L M65 and M75 having a density lower than the range defined in claim 1 were used in place of HDPE, respectively. As a result, the opening property of the film was inferior. In addition, since Comparative Example 8 uses Petrocene 183 whose SR is lower than the range defined in Claim 2, the haze is higher than that of Examples 5 to 13 in Table 8, so that the improvement of transparency by LDPE blending is improved. It is insufficient.

Claims (2)

An ethylene-α-olefin copolymer [A] that satisfies the following requirements (a) to (e) and a high-density polyethylene [B] that satisfies the following requirements (f) and (g): [A] / [ B] (weight ratio) is 99.5 / 0.5 to 80/20, polyethylene resin composition for film [I].
(A) Based on JIS K 7112: 1999, the measured density is 890 to 940 kg / m ^3.
(B) Melt flow rate (MFR) measured in accordance with JIS K 7210: 1999 under a load of 190 ° C. and 21.18 N is 0.1 to 10 g / 10 minutes (c) Weight average molecular weight (Mw) and number average Molecular weight (Mn) ratio (Mw / Mn) is 1.5-4
(D) In a differential scanning calorimeter, the endothermic curve obtained when melting at 200 ° C. for 5 minutes and then cooling to 30 ° C. at 10 ° C./min is raised at 10 ° C./min. It has a single peak, and the relationship between the temperature at the peak position (Tm (° C.)) and the number of short chain branches (SCB) per 1000 carbon atoms determined from the measurement of infrared absorption spectrum is expressed by the equation (1). Fulfill.
Tm <−1.15 × SCB + 131 (1)
(E) A copolymer of ethylene and an α-olefin having 3 or more carbon atoms.
(F) Based on JIS K 7112: 1999, the measured density is 940 to 970 kg / m ^3.
(G) Melt flow rate (MFR) measured under a load of 190 ° C. and 21.18 N measured in accordance with JIS K 7210: 1999 is 3 to 50 g / 10 min. The polyethylene resin composition [I] for film according to claim 1 and a high-pressure low-density polyethylene [C] that satisfies the following requirements (h) to (J): [I] / [C] (weight ratio) is A polyethylene resin composition for film [II], which is 100 / 0.1 to 100/10.
(H) The measured density is 915 to 935 kg / m ^{3 based on} JIS K 7112: 1999.
(I) The melt flow rate (MFR) measured under a load of 190 ° C. and 21.18 N measured in accordance with JIS K 7210: 1999 is in the range of 0.1 to 10 g / 10 min.
(J) Using the melt indexer used in JIS K 7210, dividing the diameter (D) of the extruded strand at a temperature of 235 ° C. and an extrusion rate of 3 g / min by the orifice diameter (D ₀ ) of the melt indexer The obtained swell ratio (SR) is 1.8 to 3.0.

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