JP6398841B2 - Packaging film - Google Patents

Description

  The present invention relates to a packaging film. Specifically, it is excellent in heat sealability, heat resistance and productivity, and when used as a packaging bag for contents containing liquids in an automatic filling machine such as a die roll method, high-speed liquid filling is possible in a wide temperature range from low to high The present invention relates to a packaging film that can be filled in a hot pack application.

  Conventionally, for liquids and mucilages, and liquids and mucilages containing solids such as fibers and powders as insoluble substances, a laminate obtained by laminating various layers on a substrate as necessary Film is being used. Such a laminated film includes, for example, a packaging film that has a sealant layer provided on a surface base material layer made of polyamide resin, polyethylene terephthalate resin, paper, aluminum foil, etc., and uses the heat sealability of the sealant layer. Are known.

  As resins used in the sealant layer, for example, Patent Documents 1 to 3 include random copolymers of ethylene having specific physical properties and α-olefins other than ethylene (hereinafter referred to as “ethylene / α-olefin copolymers”). And a high-pressure low-density polyethylene (hereinafter also referred to as “HPLD”) have been proposed. In Patent Document 1, as the ethylene / α-olefin copolymer, specifically, an ethylene / 4-methyl-1-pentene random copolymer produced with an Mg—Ti catalyst is shown. The packaging film using this blend composition has a drawback that the foaming start temperature of the lateral seal portion is low.

  Patent Document 2 discloses a linear low density polyethylene (ethylene) produced by a metallocene catalyst exhibiting specific temperature rising elution fractionation (hereinafter also referred to as “TREF”) characteristics as the ethylene / α-olefin copolymer. 1-hexene copolymer, etc.) is disclosed, but the packaging film using this blend composition is sealed as a foreign substance in the sealing part when the contents are filled, so that the heat sealer Depending on the pressure and temperature received from the part, there is a problem that a sealing failure occurs due to the generation of a resin reservoir (a state where the sealant layer and the intermediate layer part are raised in a bump shape) based on the peeling of the base material and the intermediate layer at the seal part. . On the other hand, if the pressure and temperature of the heat sealer are lowered, sealing failure will occur due to insufficient low-temperature heat sealability and hot tackiness of the sealant layer, resulting in reduced seal strength, reduced pressure resistance, and liquid leakage due to the presence of foreign matter. As a result, there is a problem that the filling speed cannot be increased.

  Patent Document 3 discloses a linear low density polyethylene (ethylene / 1-hexene copolymer, ethylene / 1-butene copolymer, ethylene, produced with a metallocene catalyst as the ethylene / α-olefin copolymer. -1-octene copolymer, etc.) are disclosed, but as in the case of Patent Document 2, the packaging film using this blend composition has a poor seal due to low temperature heat sealability and hot tackiness. There is a fault that tends to occur.

  On the other hand, for example, Patent Document 4 proposes a coextruded multilayer film for bonding in which a specific three-layer structure film composed of an inner layer, an intermediate layer, and an outer layer is coextruded as a base material layer. However, this laminated film has a problem that it cannot be filled with a liquid filling machine.

  Patent Document 5 proposes a three-layer structure film in which an intermediate layer having specific physical properties made of a blend composition of linear low density polyethylene and HPLD is provided on a base material layer, and a normal sealant layer is provided on the outer side thereof. ing. However, this laminated film is a bag-made product and has an advantage of having a high bag breaking strength, but has a problem that it is inferior in filling ability in a liquid filling and packaging machine.

  Patent Document 6 discloses a packaging laminate having a three-layer structure in which an ethylene / α-olefin copolymer resin or resin composition having specific thermal properties is used as an intermediate layer and a sealant layer, and the thickness is specified. Proposed. However, this laminate describes that HPLD may be blended in the ethylene / α-olefin copolymer copolymer as a sealant layer, but no specific examples are shown, and a wide range There is a problem that high-speed liquid filling suitability at the sealing temperature cannot be obtained.

  Patent Documents 7 and 8 disclose a sealant layer made of linear low density polyethylene (L-LDPE), an intermediate layer made of L-LDPE having a higher density than the sealant layer, and a base film made of a biaxially stretched film. Packaging films having an extruded three-layer structure with layers have been proposed.

  Further, Patent Document 9 discloses a laminate in which a base film, a support layer, and a sealant layer are sequentially laminated, and the support layer is polymerized using a Ziegler-Natta catalyst or a metallocene-based single site catalyst. A laminate composed of a linear low-density polyethylene resin and a sealant layer composed of a composition in which two or more specific resins are blended has been proposed.

  However, when manufacturing a film using an automatic filling device, it is necessary to adjust the setting conditions of the filling device in order to cope with various contents, differences in base materials, etc. In the conventional film as disclosed, there is a problem that the allowable range in each packaging material is not sufficient, and there is a problem that it is necessary to search for a filling condition every time, and further improvement in filling suitability is caused. It was sought after.

Japanese Patent Laid-Open No. 57-123053 JP-A-7-26079 JP-A-8-269270 JP-A-10-323948 Japanese Patent Laid-Open No. 11-10809 JP-A-11-254614 JP 2008-302977 A JP 2005-289471 A JP 2004-223728 A

  As a result of investigation by the present inventors, the cause of the poor heat sealability of the packaging film disclosed in Patent Documents 2 and 3 is that ethylene / α-olefin blended in the blend composition constituting the sealant layer As the copolymer, only one type of linear low density polyethylene was used, and it was considered that the distribution of components having different solubility characteristics in the solvent was narrow. In addition, the reason why the laminate disclosed in Patent Document 4 is inferior in filling suitability in a liquid filling packaging machine or high-speed liquid filling suitability at a wide sealing temperature is to use a Ziegler catalyst used for an inner layer (sealant layer). It was considered that a considerable amount of highly crystalline component was present in the produced linear low density polyethylene. Moreover, in the laminated body shown by the Example of patent documents 5-9, only 1 type of polyethylene resin is used for the intermediate | middle layer and / or sealant layer which comprise a laminated body, and this polyethylene resin is a solubility characteristic with respect to a solvent. It was considered that the distribution of the different components was narrow.

  The present invention has been made in view of the above-mentioned problems, and is a packaging film comprising a laminate having at least three layers of a sealant layer, an intermediate layer, and a base material layer, and has heat sealability, heat resistance, and productivity. Another object of the present invention is to provide a packaging film capable of high-speed filling and high-temperature filling in a wide temperature range from low temperature to high temperature.

  As a result of intensive studies to solve the above problems, the present inventors have found that the sealant layer and the intermediate layer are composed of a resin composition containing a polyethylene resin composition having a specific composition and physical properties, and these layers are extruded and laminated. In the case of a packaging film laminated by processing or the like, it has been found that the above problems can be solved, and the present invention has been completed.

That is, the gist of the present invention resides in the inventions of the following items.
A packaging film comprising a laminate having at least three layers of a sealant layer (A), an intermediate layer (B) and a base material layer (C), wherein the sealant layer (A) and the intermediate layer (B) are respectively A packaging film comprising a resin composition satisfying the above requirements and laminated by an extrusion lamination method or a coextrusion lamination method.
Sealant layer (A): an ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [1] to [3].
[1] The melt flow rate (MFR) with a load of 2.16 kg at 190 ° C. is in the range of 1 to 30 g / 10 min.
[2] The density is in the range of 0.900 to 0.930 g / cm ³ .
[3] In the elution curve obtained by temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (i) to (iii) are satisfied.
(I) have at least one peak at 65 ° C. or lower and above 65 ° C.
(Ii) The ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 20 to 50% by weight.
(Iii) The ratio of the eluate (S2) having an elution temperature of more than 65 ° C. is 50 to 80% by weight.
Intermediate layer (B): An ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [4] to [6] is included.
[4] The melt flow rate (MFR) with a load of 2.16 kg at 190 ° C. is in the range of 1 to 30 g / 10 min.
[5] The density is in the range of 0.910 to 0.940 g / cm ³ .
[6] An elution curve obtained by temperature-elevated elution fractionation (TREF) with orthodichlorobenzene satisfies the following (i) to (iii).
(I) It has at least one peak at 85 ° C. or lower and above 85 ° C.
(Ii) The ratio of the eluate (M1) having an elution temperature of 85 ° C. or lower is 55 to 90% by weight.
(Iii) The ratio of the eluate (M2) having an elution temperature of more than 85 ° C. is 10 to 45% by weight.

In the packaging film, the sealant layer (A) and the intermediate layer (B) preferably further satisfy the following requirements.
Sealant layer (A): an ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [1] ′ to [3] ′.
[1] The melt flow rate (MFR) at 2.16 kg load at 190 ° C. is in the range of 3 to 10 g / 10 min.
[2] The density is in the range of 0.905 to 0.920 g / cm ³ .
[3] In the elution curve obtained by the temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (ii) to (iii) are satisfied.
(Ii) The ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 25 to 45% by weight.
(Iii) The ratio of the eluate (S2) having an elution temperature exceeding 65 ° C. is 55 to 75% by weight.
Intermediate layer (B): An ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [4] ′ to [6] ′ is included.
[4] The melt flow rate (MFR) at 2.16 kg load at 190 ° C. is in the range of 3 to 10 g / 10 min.
[5] 'The density is in the range of 0.915 to 0.930 g / cm ³ .
[6] 'In the elution curve obtained by temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (ii) to (iii) are satisfied.
(Ii) The ratio of the eluate (M1) having an elution temperature of 85 ° C. or lower is 60 to 90% by weight.
(Iii) The ratio of the eluate (M2) having an elution temperature exceeding 85 ° C. is 10 to 40% by weight.

  The packaging film comprises an ethylene / α-olefin copolymer in which the sealant layer (A) is a blend of ethylene and a C 3-20 α-olefin copolymer and high-pressure low-density polyethylene. It is preferred to include a composition.

  In the packaging film, the intermediate layer (B) is an ethylene / α-olefin copolymer obtained by blending a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and a high-pressure low-density polyethylene. It is preferred to include a composition.

  In the packaging film, the sealant layer (A) contains 70 to 95% by weight of a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and 5 to 30% by weight of high-pressure low-density polyethylene. It is desirable to include an ethylene / α-olefin copolymer composition.

  In the packaging film, the intermediate layer (B) contains 70 to 95% by weight of a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and 5 to 30% by weight of high-pressure low-density polyethylene. It is desirable to include an ethylene / α-olefin copolymer composition.

  In the packaging film, the ethylene / α-olefin copolymer composition contained in the sealant layer (A) and / or the intermediate layer (B) is produced using ethylene and a carbon number of 3 to 3 produced using a metallocene catalyst. It is desirable to contain at least one copolymer with 20 α-olefins.

  The packaging film has a higher density of the ethylene / α-olefin copolymer composition of the intermediate layer (B) than the density of the ethylene / α-olefin copolymer composition of the sealant layer (A). It is preferable.

  Moreover, it is preferable that the said film for packaging is a film for packaging the content containing a liquid.

  The packaging film is preferably a hot pack film.

  The packaging film of the present invention can be filled at a high speed in a wide temperature range from a low temperature to a high temperature, and can be filled at a high temperature. Further, the packaging film of the present invention comprises a laminate having at least three layers of a sealant layer, an intermediate layer, and a base material layer, and can be produced by an extrusion lamination method or a coextrusion lamination method, and is excellent in productivity and heat sealability. . Therefore, the packaging material using this packaging film is excellent in sealing strength, pressure resistance and high temperature filling property.

FIG. 1 is an elution curve of an ethylene / α-olefin copolymer composition used for the sealant layer (A) in Examples and Comparative Examples. FIG. 2 is an elution curve of the ethylene / α-olefin copolymer composition used for the intermediate layer (B) in Examples and Comparative Examples.

  The packaging film of this embodiment is composed of a laminate having at least three layers of a sealant layer (A), an intermediate layer (B), and a base material layer (C), and the sealant layer (A) and the intermediate layer (B) And an ethylene / α-olefin copolymer composition.

1. Ethylene / α-olefin copolymer The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and the intermediate layer (B) is a random component of ethylene and an α-olefin other than ethylene. An ethylene / α-olefin copolymer which is a copolymer is included. The α-olefin used as a comonomer is an α-olefin having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms, and more preferably 4 to 8 carbon atoms. Specific examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, 4 , 4-dimethylpentene-1 and the like. Specific examples of the ethylene / α-olefin copolymer include an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and an ethylene / 1-octene copolymer.

  The α-olefin used as the comonomer may be one type or two or more types. For example, a multi-component copolymer using two or more α-olefins such as a terpolymer can be used. Specific examples include an ethylene / propylene / 1-butene terpolymer and an ethylene / propylene / 1-hexene terpolymer.

  The ethylene / α-olefin copolymer preferably has a structural unit derived from ethylene as a main component. For example, the ethylene content is 50 to 99% by weight, more preferably 60 to 97% by weight, and still more preferably. It is selected from the range of 70 to 95% by weight. The α-olefin content is preferably selected from the range of 1 to 50% by weight, more preferably 3 to 40% by weight, and still more preferably 5 to 30% by weight.

The ethylene content is a value measured by ¹³ C-NMR spectrum analysis, and a sample dissolved in orthodichlorobenzene (concentration: 300 mg / 2 mL) using hexamethyldisiloxane as a standard substance at a temperature of 120 ° C. It is measured under the conditions of a frequency of 100 MHz, a spectral width of 20000 Hz, a pulse repetition time of 10 seconds, and a flip angle of 40 degrees.

  The method for producing the ethylene / α-olefin copolymer is not particularly limited as long as an ethylene / α-olefin copolymer composition satisfying the physical properties described below can be obtained, and known methods such as a Ziegler catalyst and a metallocene catalyst are known. It can manufacture using the catalyst of. Among these, an ethylene / α-olefin copolymer having desired physical properties can be easily produced by using a metallocene catalyst.

  The metallocene catalyst is (i) a transition metal compound of Group 4 of the periodic table (hereinafter also referred to as “metallocene compound”) containing a ligand having a cyclopentadienyl skeleton, and (ii) a reaction with a metallocene compound. It is a catalyst comprising a cocatalyst that can be activated to a stable ionic state, and (iii) an organoaluminum compound as an optional component, and a known metallocene catalyst can be appropriately selected and used. Hereinafter, the components (i) to (iii) will be described.

(I) Metallocene Compound The metallocene compound is not particularly limited, and known compounds can be used. For example, JP-A-58-19309, JP-A-59-95292, JP-A-59-23011, JP-A-59-23011 EP Publication 420 , 436, US Pat. No. 5,055,438, International Publication WO91 / 04257, International Publication WO92 / 07123, and the like.

  Specifically, bis (cyclopentadienyl) zirconium dichloride, bis (indenyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride, bis (azurenyl) zirconium dichloride, bis (4,5,6,7-tetrahydroindenyl) Zirconium dichloride, (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium dichloride, methylenebis (cyclopentadienyl) zirconium dichloride, methylene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) ) Zirconium dichloride, isopropylidene (cyclopentadienyl) (3,4-dimethylcyclopentadienyl) zirconium dichloride, ethylene (cyclopentadienyl) (3,5-dimethylpenta) Enyl) zirconium dichloride, methylene bis (indenyl) zirconium dichloride, ethylene bis (2-methylindenyl) zirconium dichloride, ethylene 1,2-bis (4-phenylindenyl) zirconium dichloride, ethylene (cyclopentadienyl) (fluorenyl) Zirconium dichloride, dimethylsilylene (cyclopentadienyl) (tetramethylcyclopentadienyl) zirconium dichloride, dimethylsilylene bis (indenyl) zirconium dichloride, dimethylsilylene bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, Dimethylsilylene (cyclopentadienyl) (fluorenyl) zirconium dichloride, dimethylsilylene (cyclopentadienyl) (octahydro Olenyl) zirconium dichloride, methylphenylsilylenebis [1- (2-methyl-4,5-benzo (indenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4,5-benzoindenyl)] zirconium Dichloride, dimethylsilylenebis [1- (2-methyl-4H-azurenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylene Bis [1- (2-ethyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-ethyl-4-naphthyl-4H-azurenyl)] zirconium dichloride, diphenylsilylene Screw [1- (2- Methyl-4- (4-chlorophenyl) -4H-azurenyl)] zirconium dichloride, dimethylsilylenebis [1- (2-methyl-4- (phenylindenyl))] zirconium dichloride, dimethylsilylenebis [1- (2- Ethyl-4- (phenylindenyl))] zirconium dichloride, dimethylsilylene bis [1- (2-ethyl-4-naphthyl-4H-azurenyl)] zirconium dichloride, dimethylgermylenebis (indenyl) zirconium dichloride, dimethylgermylene Zirconium compounds such as (cyclopentadienyl) (fluorenyl) zirconium dichloride can be exemplified. In the above, a compound in which zirconium is replaced with hafnium can be used similarly. In some cases, a mixture of a zirconium compound and a hafnium compound can be used.

The metallocene compound may be used by being supported on an inorganic or organic compound carrier. The support is preferably a porous oxide of an inorganic or organic compound, specifically, an ion-exchange layered silicate, SiO ₂ , Al ₂ O ₃ , MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO. ZnO, BaO, ThO _{2 and the} like, or a mixture thereof.

(Ii) Cocatalyst Examples of the cocatalyst include organoaluminum oxy compounds (aluminoxane compounds), ion-exchangeable layered silicates, Lewis acids, boron compounds, lanthanoid salts such as lanthanum oxide, tin oxide, and the like.

(Iii) Organoaluminum compound Examples of organoaluminum compounds include trialkylaluminum such as triethylaluminum, triisopropylaluminum, triisobutylaluminum; dialkylaluminum halide; alkylaluminum sesquihalide; alkylaluminum dihalide; alkylaluminum hydride, organoaluminum alkoxide. Side etc. are mentioned.

As the polymerization method, any method can be adopted as long as the catalyst component and each monomer come into efficient contact. Specific examples include a slurry method, a gas phase fluidized bed method and a solution method in the presence of these catalysts, or a high-pressure bulk polymerization method in which a pressure is 200 kg / cm ² or more and a polymerization temperature is 100 ° C. or more. . A preferable production method includes high-pressure bulk polymerization.

  The ethylene / α-olefin copolymer may be appropriately selected from commercially available products. Examples of commercially available products include “Affinity” manufactured by DuPont Dow, “Kernel” and “Harmolex” manufactured by Nippon Polyethylene.

  The ethylene / α-olefin copolymer may be used alone or in combination of two or more. For example, the physical properties of the polyethylene resin composition can be controlled within a desired range by using two or more kinds of ethylene / α-olefin copolymers having different densities or MFRs. Since the ethylene / α-olefin copolymer produced using a metallocene catalyst has a narrow crystallinity distribution, blending various ethylene / α-olefin copolymers makes it easy to achieve the TREF physical properties described later in a desired range. Can be controlled.

  The ethylene / α-olefin copolymer can also be produced using a so-called Ziegler catalyst containing titanium and halogen. When ethylene / α-olefin copolymers having different physical properties are used in combination, the methods may be such that the copolymers may be blended together or multistage polymerization may be performed. Moreover, a metallocene catalyst and a Ziegler catalyst can be mixed and used.

2. High pressure method low density polyethylene The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and the intermediate layer (B) is a high pressure method low density polyethylene (HPLD) in addition to the ethylene / α-olefin copolymer. ) Can be included. HPLD can be obtained by a high pressure radical polymerization method, and is also referred to as a high pressure radical polymerization method low density polyethylene. HPLD has a high melt elasticity and is often used to improve neck-in particularly during extrusion lamination. Although it does not prescribe | regulate especially as a physical property of HPLD, MFR becomes like this. Preferably it is 0.2-80 g / 10min, More preferably, it is 0.5-50 g / 10min. The density is preferably 0.900~0.935g / cm ^3, more preferably particularly 0.910~0.930g / cm ^3.

3. Ethylene / α-olefin copolymer composition (1) Melt flow rate (MFR)
The ethylene / α-olefin copolymer composition constituting the sealant layer (A) has a melt flow rate (MFR) at 190 ° C. of 1 to 30 g / 10 minutes, preferably 3 to 10 g / 10 minutes. If the MFR is lower than the above range, the extrusion load when the resin is melt-extruded becomes high, and the film surface becomes rough during molding, which is not preferable. If the MFR exceeds the above range, the hot tack property at the time of heat sealing is lowered or the strength when used as a packaging material is lowered, which is not preferable. In addition, MFR is a value measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).

  The ethylene / α-olefin copolymer composition constituting the intermediate layer (B) has a melt flow rate (MFR) at 190 ° C. of 1 to 30 g / 10 minutes, preferably 3 to 10 g / 10 minutes. If the MFR is lower than the above range, the extrusion load when the resin is melt-extruded becomes high, and the film surface becomes rough during molding, which is not preferable. If the MFR exceeds the above range, the hot tack property at the time of heat sealing is lowered or the strength when used as a packaging material is lowered, which is not preferable. In addition, MFR is a value measured based on JIS-K6922-2: 1997 appendix (190 degreeC, 21.18N load).

(2) Density The ethylene / α-olefin copolymer composition constituting the sealant layer (A) has a density of 0.900 to 0.930 g / cm ³ , preferably 0.905 to 0.920 g / cm 3. ³ . If the density is higher than the above range, the low temperature heat sealability is poor. If the density is lower than the above range, it is not preferable because it tends to foam when sealed at a high temperature. In addition, a density is a value measured based on JIS-K6922-2: 1997 appendix (23 degreeC).

The ethylene / α-olefin copolymer composition constituting the intermediate layer (B) has a density of 0.910 to 0.940 g / cm ³ , preferably 0.915 to 0.930 g / cm ³ . If the density is higher than the above range, the low temperature heat sealability is poor. If the density is lower than the above range, it is not preferable because it tends to foam when sealed at a high temperature. In addition, a density is a value measured based on JIS-K6922-2: 1997 appendix (23 degreeC). Moreover, in the density within the above range, the density of the ethylene / α-olefin copolymer composition of the intermediate layer (B) is higher than the density of the ethylene / α-olefin copolymer composition of the sealant layer (A). When it is high, the balance between heat sealability and heat resistance is excellent.

  The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and the intermediate layer (B) is preferably formed by blending an ethylene / α-olefin copolymer and HPLD, respectively. More preferably, 70 to 95% by weight of the ethylene / α-olefin copolymer and 5 to 30% by weight of HPLD are blended with respect to 100% by weight of the entire α-olefin copolymer composition. The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and the intermediate layer (B) contains at least one ethylene / α-olefin copolymer produced using a metallocene catalyst. It is preferable to do.

(3) Temperature rise elution fractionation (TREF)
The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and the intermediate layer (B) has a specific crystallinity distribution and satisfies the following requirements.

  The ethylene / α-olefin copolymer composition constituting the sealant layer (A) has (i) at least one peak at 65 ° C. or lower and above 65 ° C. in an elution curve obtained by TREF using orthodichlorobenzene as a solvent. (Ii) the ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 20 to 50% by weight, and (iii) the ratio of the eluate (S2) having an elution temperature of more than 65 ° C. 50 to 80% by weight.

  The eluate (S1) having an elution temperature of 65 ° C. or lower is a component of a low crystal region, and the eluate (S2) having an elution temperature of 65 ° C. or higher is a component having relatively high crystallinity compared to S1. . When the elution curve of the ethylene / α-olefin copolymer composition constituting the sealant layer satisfies the above conditions, a film having an excellent balance between low-temperature sealing properties and heat resistance can be obtained.

  The elution curve of the ethylene / α-olefin copolymer composition constituting the sealant layer (A) has at least one peak at 65 ° C. or lower. Moreover, the minimum of the temperature of the position where the largest peak exists among peaks below 65 degreeC is 30 degreeC or more, for example, Preferably it is 40 degreeC or more, More preferably, it is 50 degreeC or more. In addition, the number of peaks present in the above range may be one or two or more.

  The elution curve also has at least one peak above 65 ° C. The upper limit of the temperature at the position where the maximum peak exists among peaks exceeding 65 ° C is, for example, 100 ° C or less, preferably 85 ° C or less, more preferably 80 ° C or less. In addition, the number of peaks present in the above range may be one or two or more.

  The ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 20 to 50% by weight, preferably 100 to 50% by weight, preferably 100% by weight of the ethylene / α-olefin copolymer composition constituting the sealant layer (A). 25 to 45% by weight. When the content of S1 is in the above range, the low temperature sealing property is excellent. On the other hand, when the ratio of S1 is larger than the above range, stickiness occurs, slipperiness deteriorates, crystallization in the high temperature seal region is slow, and foaming is likely to occur. On the other hand, if the ratio of S1 is less than the above range, the sealing performance at low temperatures is poor.

  The ratio of the eluate (S2) having an elution temperature of 65 ° C. or higher is 50 to 80% by weight, preferably 100% by weight of the ethylene / α-olefin copolymer composition constituting the sealant layer (A), preferably It is 55 to 80 weight%, More preferably, it is 55 to 75 weight%. When the ratio of S2 is in the above range, the heat resistance and the extrusion laminate processability are excellent. Further, the crystallization speed at the time of heat sealing is increased, and as a result, the seal appearance is excellent. Moreover, when the ratio of S2 is more than the said range, low temperature sealing performance will deteriorate. On the other hand, if the ratio of S2 is less than the above range, seal retraction occurs or foaming occurs at a high temperature, and the appearance of the resulting packaged product is impaired.

  The ethylene / α-olefin copolymer composition constituting the intermediate layer (B) has (i) at least one peak at 85 ° C. or lower and above 85 ° C. in an elution curve obtained by TREF using orthodichlorobenzene as a solvent. (Ii) the ratio of the eluate (M1) having an elution temperature of 85 ° C. or lower is 55 to 90% by weight, and (iii) the ratio of the eluate (M2) having an elution temperature of more than 85 ° C. 10 to 45% by weight.

  The eluate (M1) having an elution temperature of 85 ° C. or lower contains a component having higher crystallinity than S1 and S2, and the eluate (M2) having an elution temperature of more than 85 ° C. is more crystalline than M1. It is a high component. When the elution curve satisfies the above conditions, the polyethylene resin composition constituting the intermediate layer (B) can obtain a film having an excellent balance between low-temperature sealing properties and heat resistance.

  The elution curve of the ethylene / α-olefin copolymer composition constituting the intermediate layer (B) has at least one peak at 85 ° C. or lower. The lower limit of the temperature at which the maximum peak is present among the peaks at 85 ° C. or lower is, for example, 40 ° C. or higher, preferably 50 ° C. or higher, more preferably higher than 65 ° C. In addition, the number of peaks present in the above range may be one or two or more.

  The elution curve also has at least one peak above 85 ° C. The upper limit of the temperature at the position where the maximum peak is present among peaks exceeding 85 ° C. is, for example, 110 ° C. or less, and preferably 100 ° C. or less. In addition, the number of peaks present in the above range may be one or two or more.

  In the ethylene / α-olefin copolymer composition constituting the intermediate layer (B), the proportion of the eluate (M1) having an elution temperature of 85 ° C. or less is the same as that of the ethylene / α-olefin copolymer constituting the intermediate layer (B). It is 55 to 90% by weight, preferably 60 to 90% by weight, more preferably 60 to 85% by weight based on 100% by weight of the whole polymer composition. When M1 is in the above range, the low-temperature sealing property and the extrusion lamination processability are excellent. Moreover, since the crystallization speed at the time of heat sealing becomes slow and the fluidity is improved, the intermediate layer is easily crushed and the low temperature sealing property is improved. On the other hand, when the ratio of M1 is less than the above range, the low temperature sealing property is inferior.

  In the ethylene / α-olefin copolymer composition constituting the intermediate layer (B), the proportion of the eluate (M2) having an elution temperature of more than 85 ° C. is the same as the ethylene / α-olefin copolymer constituting the intermediate layer (B). It is 10 to 45% by weight, preferably 10 to 40% by weight, and more preferably 15 to 40% by weight with respect to 100% by weight of the whole polymer composition. When the ratio of M2 is in the above range, the heat resistance is excellent. Further, the crystallization speed at the time of heat sealing is increased, and as a result, the seal appearance is excellent. On the other hand, when the ratio of M2 is larger than the above range, the low temperature sealing property is deteriorated. On the other hand, if the ratio of M2 is smaller than the above range, seal retraction occurs or foaming occurs at a high temperature, and the appearance of the resulting packaged product is impaired.

(Measurement method of TREF)
Hereinafter, a specific method of TREF measurement will be described. The column temperature drop rate is adjusted to the rate required for crystallization of the crystalline component contained in the sample at each temperature, and the column temperature increase rate is adjusted to the rate at which dissolution of the eluted component at each temperature can be completed. It is necessary to determine the cooling rate and the heating rate of the column temperature through preliminary experiments. The measurement conditions are as follows.
Equipment: CFC-T102L manufactured by Dia Instruments
GPC column: Showa Denko AD-806MS (3 connected in series)
Solvent: orthodichlorobenzene (ODCB)
Sample concentration: 3 mg / mL
Injection volume: 0.4mL
Crystallization rate: 1 ° C / min Solvent flow rate: 1 mL / min Elution temperature 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 49, 52, 55, 58, 61, 64, 67, Each temperature (° C.) of 70, 73, 76, 79, 82, 85, 88, 91, 94, 97, 100, 102, 120, 140

(Data analysis of TREF)
The chromatogram of the eluted components at each elution temperature obtained by TREF measurement is processed by a data processing program attached to the apparatus, and the eluted amount (proportional to the area of the chromatogram) normalized so that the total is 100%. Desired. In addition, an integrated elution curve for the elution temperature is calculated. The integrated elution curve is differentiated with temperature to obtain a differential elution curve. In this specification, the peak means a convex inflection point in the differential elution curve, and includes not only a peak showing a clear convex but also a so-called shoulder.

  1 and 2 show differential elution curves obtained by TREF measurement of ethylene / α-olefin copolymer compositions obtained in Examples and Comparative Examples described later. FIG. 1 shows a differential elution curve of the sealant layer, having one peak between 50 ° C. and 60 ° C. as a peak of 65 ° C. or less, and a peak between 70 ° C. and 80 ° C. as a peak exceeding 65 ° C. One. Moreover, FIG. 2 shows the differential elution curve of the intermediate layer. For example, in FIG. 2B, as a peak of 85 ° C. or less, one maximum peak between 60 ° C. and 70 ° C. and between 70 ° C. and 80 ° C. Has a small peak, and has a peak between 90 and 100 ° C. as a peak above 85 ° C.

  In the sealant layer (A) and the intermediate layer (B), the method for adjusting the elution curve by TREF to satisfy the above conditions is not particularly limited, and various methods can be used. For example, since TREF data is generally additive, when an ethylene / α-olefin copolymer composition is produced by mixing two or more types of ethylene / α-olefin copolymers or HPLD, individual copolymers are used. The TREF characteristics can be controlled by slightly increasing / decreasing the ratio of the mixed components after predicting the mixing ratio for obtaining a desired TREF pattern based on the TREF data of the polymer or HPLD. Further, by using an ethylene / α-olefin copolymer produced using a metallocene catalyst, a polyethylene resin composition having a narrow crystallinity distribution and a sharp peak can be obtained.

  The ethylene / α-olefin copolymer composition is an antioxidant, a heat stabilizer, a weather stabilizer, a light stabilizer, an ultraviolet absorber, an antistatic agent, as long as the effects of the present invention are not significantly impaired. Antifogging agents, crystal nucleating agents, neutralizing agents, metal deactivators, colorants, dispersants, slip agents, peroxides, organic or inorganic fillers, optical brighteners, pigments and the like can be included. The polyethylene resin composition can contain a small amount of resin components other than the ethylene / α-olefin copolymer and the high-pressure low-density polyethylene as long as the effects of the present invention are not significantly impaired.

4). Packaging Film The packaging film of the present embodiment is composed of a laminate having at least three layers of a sealant layer (A), an intermediate layer (B), and a base material layer (C) in this order, and the sealant layer (A) and the intermediate layer. The layer (B) is laminated on the base material layer (C) by an extrusion lamination method or a coextrusion lamination method.

  Examples of the base material layer (C) include films such as paper, aluminum foil, cellophane, woven fabric, non-woven fabric, and high-molecular polymer. Examples thereof include high-density polyethylene, medium-density polyethylene, low-density polyethylene, and ethylene / vinyl acetate. Copolymer, ethylene / acrylic acid ester copolymer, ionomer, polypropylene, poly-1-butene, olefin polymer such as poly-4-methylpentene-1, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyacrylate, Vinyl copolymers such as polyacrylonitrile, nylon 6, nylon 66, nylon 7, nylon 10, nylon 11, nylon 12, nylon 610, polyamides such as polymethaxylylene adipamide, polyethylene terephthalate, polyethylene terephthalate / isophthalate, polybutyl Polyesters such as terephthalate, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, may be mentioned a film of polycarbonate. One type of film used as the base material layer (C) may be used, or two or more types may be used. Further, the film may be stretched depending on the type of substrate. Examples of the stretched film include a uniaxial or biaxially stretched polypropylene film, a stretched nylon film, a stretched polyethylene terephthalate film, and a stretched polystyrene film. Further, a material obtained by coating polyvinylidene chloride or polyvinyl alcohol on the above film, or a material obtained by vapor-depositing aluminum, alumina, silica, or a mixture of alumina and silica may be used as the base material layer C). In the case of a packaging film containing a liquid or a viscous material, the base material layer (C) is a biaxially stretched nylon film, a biaxially stretched polyethylene terephthalate film, or a material in which silica or alumina is vapor-deposited on the base material. be able to.

  Usually, as a method for producing a laminate, for example, a dry lamination method, a wet lamination method, an extrusion method, a sandwich lamination method, a co-extrusion method and the like can be mentioned. For example, the packaging film used for dry lamination and the like includes any method such as a calendar method, an air-cooled inflation method, a water-cooled inflation method, and a T-die molding method. In the case of an extrusion method, an extrusion lamination method, a dry lamination method, a sandwich lamination method, a coextrusion lamination method (coextrusion without an adhesive layer, coextrusion with an adhesive layer, coextrusion with an adhesive resin, etc. are included. ) Etc.

  In the packaging film of this embodiment, when laminating the sealant layer (A) and the intermediate layer (B) on at least one surface of the base material layer (C), an extrusion laminating method or a coextrusion laminating method is preferably used. It is done. By using these methods, the productivity of the film is excellent. For example, a tandem extrusion laminating method is suitably used as a method for producing a packaging material for contents containing liquid, mucilage, etc. from the viewpoint of productivity and quality. The tandem extrusion laminating method is a method of sequentially laminating two types of resin layers. For example, the intermediate layer (B) is laminated as the first layer on the base material layer (C) by the extrusion laminating method, and further two layers are formed. In this method, the sealant layer (A) is laminated as an eye.

  There is no restriction | limiting in particular about the thickness of the whole laminated body, the thickness of each layer, and the thickness ratio of each layer, and the laminated body which comprises the film for packaging can be suitably selected according to a content, a use, etc. The thickness of the entire laminate is, for example, 40 to 120 μm, the thickness of the base material layer is 10 to 40 μm, and the thickness of the sealant layer is about 10 to 40 μm. When providing an intermediate layer, the thickness of the intermediate layer can be about 20 to 40 μm. Further, in the case of lamination, surface treatment such as corona discharge treatment, ozone treatment, flame treatment or the like can be performed on the substrate layer in advance in order to improve the adhesion of the substrate surface. Furthermore, in order to enhance the adhesion, etc., the anchor coating agent can be applied on the substrate in advance and then laminated. Examples of the anchor coating agent include isocyanate-based, polyethyleneimine-based, and polybutadiene-based agents.

  The packaging film of this embodiment can be used as various packaging materials such as food packaging materials, medical packaging materials, and industrial material packaging materials such as engine oil. Especially, it is used suitably as a packaging material for accommodating fluids, such as a liquid, a liquid, a viscous body, etc. containing solid insoluble matters, such as a fiber, a fiber, and a powder. In addition, since it has excellent heat resistance, high-speed filling is possible at a content temperature of at least 95 ° C. or lower, and it is suitable as a packaging material for hot packs that fills a liquid-containing content at a high temperature (eg, 90 ° C. or higher). Used for.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. The measurement methods, evaluation methods, and resin materials used in the examples and comparative examples are as follows.

[Measuring method]
(1) Performed according to MFR: JIS K6922-2: 1997 appendix (190 ° C., 21.18 N load).
(2) Density: Performed according to JIS K6922-2: 1997 appendix (23 ° C.).

[Film evaluation method]
(1) Filling of liquid Using a viscous material automatic filling and packaging machine (manufactured by Sanko Machine Co., Ltd., FR-3), liquid was filled under the following conditions.
[Filling conditions]
Sealing temperature: (vertical) 185 ° C, (horizontal) 110 ° C-180 ° C
Packaging style: Three-side seal Bag dimensions: 100mm width x 150mm length Filling: Water 95 ° C (hot pack filling)
Filling amount: about 40g
Filling speed: 25m / min

(2) Evaluation of hot pack filling Filling was performed by changing the horizontal seal temperature under the above conditions, and the evaluation was performed by the following method.
[Pressure resistance condition]
A load was applied at 100 kg for 1 minute with a pressure tester (manufactured by Komatsu Ltd.), and the presence or absence of bag breakage, seal receding, or water leakage was evaluated.
[Evaluation criteria]
Appearance of horizontal seal is good, there is no broken bag or water leakage in pressure resistance evaluation, and no foaming is observed. The case where it was able to confirm was evaluated as x.

(3) Boil evaluation The sealant surfaces of the film for evaluation were put together, sandwiched between clips, boiled at 95 ° C. for 1 minute, and the presence or absence of fusion of the film was visually observed. The presence or absence of fusion was evaluated with ◯ when no film fusion was confirmed and x when film fusion was confirmed.

(4) Evaluation of occurrence of poly stagnation The presence or absence of poly stagnation in the heat seal part of the evaluation film filled at a high temperature (95 ° C.) was visually observed. The case where a poly pool was not observed in the heat seal part was evaluated as ◯, and the case where a poly pool was observed was evaluated as x.

(5) Low back feeling The low back feeling of the packaging film was evaluated with a loop step tester (manufactured by Toyo Seiki Co., Ltd.).
[Evaluation conditions]
Test dimensions: MD, TD direction, width 25 mm, length 120 mm
Force measurement range: 20g (display 19.99g)
Compression speed: 3.5 mm / min
For each sample, the loop stiffness strength was measured five times in the longitudinal direction and the transverse direction.

[Resin used]
P1: ethylene / 1-hexene copolymer (linear low density polyethylene (mLLDPE) produced using a metallocene catalyst, MFR 2 g / 10 min, density 0.898 g / cm ³ )
P2: ethylene / 1-hexene copolymer (mLLD, MFR 10 g / 10 min, density 0.900 g / cm ³ )
P3: ethylene / 1-hexene copolymer (mLLD, MFR 4 g / 10 min, density 0.918 g / cm ³ )
P4: ethylene / 1-hexene copolymer (mLLD, MFR 9 g / 10 min, density 0.918 g / cm 3)
P5: ethylene / 1-hexene copolymer (mLLD, MFR 4 g / 10 min, density 0.918 g / cm ³ )
P6: ethylene / 1-hexene copolymer (mLLD, MFR 8 g / 10 min, density 0.919 g / cm ³ )
P7: ethylene / 1-hexene copolymer (linear low density polyethylene (LLDPE) produced using a Cr catalyst, MFR 2 g / 10 min, density 0.935 g / cm ³ )
P8: ethylene / 1-propene copolymer (high density polyethylene (HDPE) produced using Zn catalyst, MFR 7 g / 10 min, density 0.962 g / cm ³ )
P9: High-pressure method low density polyethylene (HPLD) (MFR 4 g / 10 min, density 0.918 g / cm ³ )

[Example 1]
[Sealant layer]
P1: 38 wt% and P4: 40 wt% were used as the ethylene / α-olefin copolymer, and P9: 22 wt% was used as the high pressure method low density polyethylene. 100 parts by weight of the above resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (A1). As shown in FIG. 1 (A1), a peak at about 57 ° C. based on P1 and a peak at about 74 ° C. based on P4 and P9 were observed in the TREF curve.
[Middle layer]
P5: 65 wt% and P6: 15 wt% were used as the ethylene / α-olefin copolymer, and P9: 20 wt% was used as the high pressure method low density polyethylene. The above resin was well blended in a blender and melt extruded to form pellets to obtain an ethylene / α-olefin copolymer composition (B1). As shown in FIG. 2 (B1), in the TREF curve, a peak at about 73 ° C. based on P5, P6 and P9 and a peak at about 88 ° C. based on P5 and P6 were observed.
[Production of evaluation film]
Using an extrusion laminating machine, a biaxially stretched nylon film (Harden film N1102 manufactured by Toyobo Co., Ltd.) having a width of 500 mm and a thickness of 15 μm is used as a base material layer, and an isocyanate anchor coating agent (Nitta Soda Chitabond T120 solution) is bowed thereon. While applying with a roll and spraying ozone at the laminating part, the ethylene / α-olefin copolymer composition of the intermediate layer material is taken out and melt extruded and laminated at a coating thickness of 25 μm at a coating thickness of 25 μm. The intermediate layer was laminated. The extrusion laminator is set so that the temperature of the resin extruded from the T-die mounted on an extruder with a diameter of 90 mmφ is 300 ° C, and is taken up at a cooling roll surface temperature of 25 ° C, a die width of 560 mm, and a die lip opening of 0.7 mm. The extrusion amount was adjusted so that the coating thickness was 25 μm when the processing speed was 100 m / min.
Further, on this intermediate layer, the same extrusion laminating apparatus was used, and the ethylene / α-olefin copolymer composition of the sealant layer material was melt extruded and laminated at an extrusion resin temperature of 290 ° C., a take-off speed of 100 m / min, and a coating thickness of 25 μm. The sealant layer was laminated.
The laminated film after processing was aged for 48 hours in an oven at 40 ° C., and then slitted to a width of 150 mm to obtain a packaging film for evaluation. The evaluation results of the obtained film are shown in Table 2.

[Example 2]
A film for evaluation was produced in the same manner as in Example 1 except that the ethylene / α-olefin copolymer compositions (A2) and (B2) of the sealant layer material and intermediate layer material obtained by the following method were used. did. The evaluation results of the film are shown in Table 2.
[Sealant layer]
P2: 38 wt% and P3: 40 wt% were used as the ethylene / α-olefin copolymer, and P9: 22 wt% was used as the high pressure method low density polyethylene. 100 parts by weight of the above resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (A2). As shown in FIG. 1 (A2), in the TREF curve, a peak at about 55 ° C. based on P2 and a peak at about 76 ° C. based on P3 and P9 were observed.
[Middle layer]
P6: 50% by weight and P7: 30% by weight were used as the ethylene / α-olefin copolymer, and P9: 20% by weight was used as the high-pressure low-density polyethylene. The above resin was well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (B2). As shown in FIG. 2 (B2), in the TREF curve, a peak at about 67 ° C. based on P6, a peak at about 76 ° C. based on P9, and a peak at about 94 ° C. based on P6 and P7 were observed.

[Example 3]
A film for evaluation was prepared in the same manner as in Example 1 except that the ethylene / α-olefin copolymer compositions (A2) and (B3) of the sealant layer material and intermediate layer material obtained by the following method were used. did. The evaluation results of the film are shown in Table 2.
[Sealant layer]
P2: 38 wt% and P3: 40 wt% were used as the ethylene / α-olefin copolymer, and P9: 22 wt% was used as the high-pressure low-density polyethylene. 100 parts by weight of the above resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt extruded to form pellets to obtain an ethylene / α-olefin copolymer composition. As shown in FIG. 1 (A2), a peak at about 55 ° C. based on P2 and a peak at about 76 ° C. based on P3 and P9 were observed in the TREF curve.
[Middle layer]
As the ethylene / α-olefin copolymer, P5: 55% by weight, P8: 25% by weight as high-density polyethylene, and P9: 20% by weight as high-pressure low-density polyethylene were used. The above resin was thoroughly blended in a blender and melt extruded to form pellets, whereby an ethylene / α-olefin copolymer composition (B3) was obtained. As shown in FIG. 2 (B3), the TREF curve has a peak at about 66 ° C. based on P5, a peak at about 77 ° C. based on P9, a peak at about 90 ° C. based on P5, and a temperature of about 96 ° C. based on P8. The peak was observed.

[Comparative Example 1]
A film for evaluation was prepared in the same manner as in Example 1 except that the ethylene / α-olefin copolymer compositions (A2) and (B4) of the sealant layer material and intermediate layer material obtained by the following method were used. did. The evaluation results of the film are shown in Table 2.
[Sealant layer]
As the ethylene / α-olefin copolymer, P2: 38% by weight, P3: 40% by weight, and P9: 22% by weight as the high-pressure low-density polyethylene were used. 100 parts by weight of the above resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (A2). As shown in FIG. 1 (A2), in the TREF curve, a peak at about 55 ° C. based on P2 and a peak at about 76 ° C. based on P3 and P9 were observed.
[Middle layer]
P3: 80% by weight was used as the ethylene / α-olefin copolymer, and P9: 20% by weight was used as the high-pressure low-density polyethylene. The above resin was well blended in a blender and melt extruded to form pellets, whereby an ethylene / α-olefin copolymer composition (B4) was obtained. As shown in FIG. 2 (B4), a peak at about 77 ° C. based on P3 and P9 was observed in the TREF curve.

[Comparative Example 2]
A film for evaluation was produced in the same manner as in Example 1 except that the ethylene / α-olefin copolymer compositions (A3) and (B4) of the sealant layer material and intermediate layer material obtained by the following method were used. did. The evaluation results of the film are shown in Table 2.
[Sealant layer]
P1: 53 wt% was used as the ethylene / α-olefin copolymer, P4: 25 wt%, and P9: 22 wt% was used as the high-pressure low-density polyethylene (LDPE). 100 parts by weight of the resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (A3). As shown in FIG. 1 (A3), in the TREF curve, a peak at about 57 ° C. based on P1 and a peak at about 73 ° C. based on P4 and P9 were observed.
[Middle layer]
P3: 80% by weight was used as the ethylene / α-olefin copolymer, and P9: 20% by weight was used as the high-pressure low-density polyethylene (LDPE). The above resin was well blended in a blender and melt extruded to form pellets, whereby an ethylene / α-olefin copolymer composition (B4) was obtained. As shown in FIG. 2 (B4), a peak at about 77 ° C. based on P3 and P9 was observed in the TREF curve.

[Comparative Example 3]
A film for evaluation was produced in the same manner as in Example 1 except that the ethylene / α-olefin copolymer compositions (A3) and (B2) of the sealant layer material and intermediate layer material obtained by the following method were used. did. The evaluation results of the film are shown in Table 2.
[Sealant layer]
P1: 53 wt% was used as the ethylene / α-olefin copolymer, P4: 25 wt%, and P9: 22 wt% was used as the high-pressure low-density polyethylene (LDPE). 100 parts by weight of the resin and 0.06 parts by weight of an aliphatic amide slip agent were well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (A3). As shown in FIG. 1 (A3), in the TREF curve, a peak at about 57 ° C. based on P1 and a peak at about 73 ° C. based on P4 and P9 were observed.
[Middle layer]
P6: 50% by weight and P7: 30% by weight were used as the ethylene / α-olefin copolymer, and P9: 20% by weight was used as the high-pressure low-density polyethylene. The above resin was well blended in a blender and melt-extruded into pellets to obtain an ethylene / α-olefin copolymer composition (B2). As shown in FIG. 2 (B2), in the TREF curve, a peak at about 67 ° C. based on P6, a peak at about 76 ° C. based on P9, and a peak at about 94 ° C. based on P6 and P7 were observed.

[Evaluation results]
The films of Examples 1 to 3 were excellent in filling suitability, heat resistance during hot pack filling and appearance, and were capable of high-speed liquid filling in a wide range from low temperature to high temperature. Especially, since the film of Example 2 had a wider melting temperature distribution of the intermediate layer than that of Example 1, a wide filling temperature was obtained by hot pack filling. In addition, the film of Example 3 includes HDPE having a high proportion of high melting point components in the intermediate layer, and is superior in back feeling compared to Example 1.
On the other hand, since Comparative Example 1 has a narrow melting temperature distribution of the intermediate layer, it is inferior in hot pack filling suitability and the like as compared with the Examples. Further, in Comparative Example 2, in the melting temperature distribution of the sealant layer, the ratio of the eluate (S1) having an elution temperature of 65 ° C. or less is higher than the ratio of the eluate (S2) exceeding 65 ° C. Since the temperature distribution is narrow, it is inferior to room temperature filling suitability and hot pack filling suitability as compared with the examples. In Comparative Example 3, in the melt temperature distribution of the sealant layer, the ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is higher than the ratio of the eluate (S2) exceeding 65 ° C. Due to the wide temperature distribution, a wide filling temperature was obtained by hot pack filling, but fusion with a sealant was confirmed and the heat resistance was poor.

Claims (10)

A packaging film comprising a laminate having at least three layers of a sealant layer (A), an intermediate layer (B) and a base material layer (C), wherein the sealant layer (A) and the intermediate layer (B) are respectively A packaging film comprising a resin composition satisfying the above requirements and laminated by an extrusion lamination method or a coextrusion lamination method.
Sealant layer (A): an ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [1] to [3].
[1] The melt flow rate (MFR) with a load of 2.16 kg at 190 ° C. is in the range of 1 to 30 g / 10 min.
[2] The density is in the range of 0.900 to 0.930 g / cm ³ .
[3] In the elution curve obtained by temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (i) to (iii) are satisfied.
(I) have at least one peak at 65 ° C. or lower and above 65 ° C.
(Ii) The ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 20 to 50% by weight.
(Iii) The ratio of the eluate (S2) having an elution temperature of more than 65 ° C. is 50 to 80% by weight.
Intermediate layer (B): An ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [4] to [6] is included.
[4] The melt flow rate (MFR) with a load of 2.16 kg at 190 ° C. is in the range of 1 to 30 g / 10 min.
[5] The density is in the range of 0.910 to 0.940 g / cm ³ .
[6] An elution curve obtained by temperature-elevated elution fractionation (TREF) with orthodichlorobenzene satisfies the following (i) to (iii).
(I) It has at least one peak at 85 ° C. or lower and above 85 ° C.
(Ii) The ratio of the eluate (M1) having an elution temperature of 85 ° C. or lower is 55 to 90% by weight.
(Iii) The ratio of the eluate (M2) having an elution temperature of more than 85 ° C. is 10 to 45% by weight. The packaging film according to claim 1, wherein the sealant layer (A) and the intermediate layer (B) further satisfy the following requirements, respectively.
Sealant layer (A): an ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [1] ′ to [3] ′.
[1] The melt flow rate (MFR) at 2.16 kg load at 190 ° C. is in the range of 3 to 10 g / 10 min.
[2] The density is in the range of 0.905 to 0.920 g / cm ³ .
[3] In the elution curve obtained by the temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (ii) to (iii) are satisfied.
(Ii) The ratio of the eluate (S1) having an elution temperature of 65 ° C. or lower is 25 to 45% by weight.
(Iii) The ratio of the eluate (S2) having an elution temperature exceeding 65 ° C. is 55 to 75% by weight.
Intermediate layer (B): An ethylene / α-olefin copolymer composition that simultaneously satisfies the following requirements [6] ′ to [8] ′ is included.
[4] The melt flow rate (MFR) at 2.16 kg load at 190 ° C. is in the range of 3 to 10 g / 10 min.
[5] 'The density is in the range of 0.915 to 0.930 g / cm ³ .
[6] 'In the elution curve obtained by temperature rising elution fractionation (TREF) with orthodichlorobenzene, the following (ii) to (iii) are satisfied.
(Ii) The ratio of the eluate (M1) having an elution temperature of 85 ° C. or lower is 60 to 90% by weight.
(Iii) The ratio of the eluate (M2) having an elution temperature exceeding 85 ° C. is 10 to 40% by weight.   The sealant layer (A) includes an ethylene / α-olefin copolymer composition formed by blending a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and a high-pressure low-density polyethylene. The packaging film according to claim 1 or 2.   The intermediate layer (B) includes an ethylene / α-olefin copolymer composition obtained by blending a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and a high-pressure low-density polyethylene. The packaging film according to claim 1 or 2.   The sealant layer (A) is an ethylene / α-olefin copolymer comprising 70 to 95% by weight of a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and 5 to 30% by weight of a high-pressure low-density polyethylene. The packaging film according to claim 1, comprising a polymer composition.   The intermediate layer (B) is an ethylene / α-olefin copolymer comprising 70 to 95% by weight of a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms and 5 to 30% by weight of a high-pressure low-density polyethylene. The packaging film according to claim 1, comprising a polymer composition.   The ethylene / α-olefin copolymer composition contained in the sealant layer (A) and / or the intermediate layer (B) is a copolymer of ethylene produced using a metallocene catalyst and an α-olefin having 3 to 20 carbon atoms. The packaging film according to claim 1, comprising at least one polymer.   The density of the ethylene / α-olefin copolymer composition contained in the intermediate layer (B) is higher than the density of the ethylene / α-olefin copolymer composition contained in the sealant layer (A). The packaging film according to any one of claims 1 to 7.   It is a film for packaging the content containing a liquid, The film for packaging as described in any one of Claims 1-8 characterized by the above-mentioned. It is a hot pack use, The packaging film as described in any one of Claims 1-9 characterized by the above-mentioned.

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