Film, and method for manufacturing the film

Abstract

To provide a film comparatively excellent in heat sealability, and a production method of a film.SOLUTION: A film related to the invention includes a propylene-based polymer containing a structural unit derived from propylene of more than 50 mass% and an ethylene-based polymer containing a structural unit derived from ethylene of more than 50 mass%. The film has a content of the propylene-based polymer of 50 mass% or more and 95 mass% or less and a content of the ethylene-based polymer of 5 mass% or more and 50 mass% or less relative to 100 mass% of the total content of the propylene-based polymer and the ethylene-based polymer. The film has a lamella orientation index in a film flow direction (MD) of 1.20 or higher and 3.20 or lower in the region from at least one surface of the film to the 10 μm depth.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a film and a method for manufacturing the film.

Background Art

[0002] Conventionally, as a film for packaging an object to be packaged such as food, a multilayer film in which a base film and a sealant film are laminated has been widely used. Such a multilayer film is overlapped so that the sealant film is on the inside, and heat-sealed to form a space for accommodating the object to be packaged, thereby forming a packaging bag.

[0003] The sealant film is required to be excellent in heat-sealability and impact resistance. In addition, since a packaging bag formed using the sealant film may be heated for the purpose of sterilization or the like, the sealant film is also required to be excellent in heat resistance. As a sealant film having such performance, for example, Patent Document 1 discloses a film containing a propylene-based polymer and an ethylene-based polymer. In such a film, it is known that the propylene-based polymer plays a role of improving heat resistance and heat-sealability, and the ethylene-based polymer plays a role of improving impact resistance.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, even in the film as described above, there is room for improvement in heat-sealability, and a film having more excellent heat-sealability is desired.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a film having relatively excellent heat sealability and a method for producing the film.

Means for Solving the Problems

[0007] The film according to the present invention contains a propylene-based polymer containing more than 50% by mass of structural units derived from propylene and an ethylene-based polymer containing more than 50% by mass of structural units derived from ethylene, and based on 100% by mass in total of the content of the propylene-based polymer and the content of the ethylene-based polymer, the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less, and the lamellar orientation index in the machine direction (MD) of the film in the region from the film surface to a depth of 10 μm is 1.20 or more and 3.20 or less.

[0008] The method for producing a film according to the present invention contains a propylene-based polymer containing more than 50% by mass of structural units derived from propylene and an ethylene-based polymer containing more than 50% by mass of structural units derived from ethylene, and based on 100% by mass in total of the content of the propylene-based polymer and the content of the ethylene-based polymer, the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less. The method includes a step (1) of melt-kneading the resin composition under the conditions of 200°C or higher and 350°C or lower, and a step of extruding the melt-kneaded resin composition from a T-die using an extruder equipped with a screw as a resin composition for forming the surface layer portion of the film, where the screw rotation speed is 20 rpm or more and 200 rpm or less, the extrusion amount is 10 kg / h or more and 500 kg / h or less, and the extrusion temperature of the T-die is T1°C (step (2)), and a step (3) of forming a film from the extruded resin composition under the conditions of a cooling temperature of T2°C and a film forming speed of 10 m / min or more and less than 70 m / min, and satisfies the following formula (11). 180 ≦ T1 - T2 ≦ 250 (11)

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a film having relatively excellent heat sealability and a method for manufacturing the film.

Brief Description of Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0012] [Film] The film according to the present embodiment contains a propylene-based polymer and an ethylene-based polymer.

[0013] <Propylene-based polymer> The propylene-based polymer is a polymer containing more than 50% by mass of structural units derived from propylene, that is, a propylene homopolymer or a propylene-based copolymer containing more than 50% by mass of structural units derived from propylene. Examples of the structural units other than propylene contained in the propylene-based copolymer include structural units derived from ethylene and α-olefins having 4 to 12 carbon atoms.

[0014] Examples of the propylene-based copolymer include propylene-based random copolymers. Examples of the propylene-based random copolymer include propylene-ethylene random copolymers, propylene-α-olefin random copolymers, propylene-ethylene-α-olefin terpolymers, and the like.

[0015] Examples of α-olefins having 4 to 12 carbon atoms include 1-butene, 2-methyl-1-propene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 2-ethyl-1-butene, 2,3-dimethyl-1-butene, 2-methyl-1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3,3-dimethyl-1-butene, 1-heptene, methyl-1-hexene, dimethyl-1-pentene, ethyl-1-pentene, trimethyl-1-butene, methylethyl-1-butene, 1-octene, methyl-1-pentene, ethyl-1-hexene, dimethyl-1-hexene, propyl-1-heptene, methylethyl-1-heptene, trimethyl-1-pentene, propyl-1-pentene, diethyl-1-butene, 1-nonene, 1-decene, 1-undecene, 1-dodecene and the like. Preferably, it is 1-butene, 1-pentene, 1-hexene or 1-octene, more preferably 1-butene or 1-hexene from the viewpoints of copolymerization characteristics, economy, etc., and still more preferably 1-butene.

[0016] The propylene-based polymer is preferably a propylene homopolymer or a propylene-based random copolymer, more preferably a propylene homopolymer or a propylene-ethylene random copolymer. The film according to this embodiment may contain only one kind of propylene-based polymer, or may contain two or more kinds of propylene-based polymers having different types and contents of structural units.

[0017] When the propylene-based polymer is a propylene-ethylene random copolymer, the structural unit derived from ethylene is usually contained in an amount of 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 6% by mass or less, and still more preferably 2% by mass or more and 6% by mass or less.

[0018] When the propylene-based polymer is a propylene-ethylene-α-olefin terpolymer, the structural unit derived from ethylene is usually contained in an amount of 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more and 10% by mass or less, more preferably 0.5% by mass or more and 5% by mass or less, and still more preferably 0.5% by mass or more and 3% by mass or less. Further, the structural unit derived from α-olefin is usually contained in an amount of 0.1% by mass or more and 20% by mass or less, preferably 0.5% by mass or more and 10% by mass or less, more preferably 1% by mass or more and 10% by mass or less, and still more preferably 3% by mass or more and 10% by mass or less.

[0019] From the viewpoint of heat resistance, the melting point of the propylene-based polymer is preferably 120°C or higher and 170°C or lower, and more preferably 130°C or higher and 170°C or lower.

[0020] The melt flow rate (MFR) of the propylene-based polymer measured at a temperature of 230°C and a load of 2.16 kg is preferably 1 g / 10 min or more and 10 g / 10 min or less, and more preferably 1 g / 10 min or more and 5 g / 10 min or less. The MFR of the propylene-based polymer is measured according to Method A specified in JIS K7210-1.

[0021] Examples of the method for producing the propylene-based polymer include a method of homopolymerizing propylene in the presence of a Ziegler-Natta type catalyst or a metallocene catalyst, and a method of copolymerizing an olefin other than propylene with propylene.

[0022] Examples of the Ziegler-Natta type catalyst include a catalyst obtained by combining a titanium-containing solid transition metal component and an organometallic component. Examples of the metallocene catalyst include a catalyst obtained by combining a transition metal compound of Groups 4 to 6 of the periodic table having at least one cyclopentadienyl skeleton and a cocatalyst component.

[0023] Examples of the polymerization method include a slurry polymerization method and a solution polymerization method carried out in an inert hydrocarbon solvent, and a liquid phase polymerization method and a gas phase polymerization method carried out in the absence of a solvent.

[0024] In the production of a propylene-based polymer, in order to remove residual solvents, ultra-low molecular weight oligomers by-produced during production, etc., the produced propylene-based polymer may be dried at a temperature equal to or lower than the temperature at which the propylene-based polymer melts. Examples of the drying method include the methods described in JP-A-55-75410 and Japanese Patent No. 2565753.

[0025] The propylene-based polymer may be a propylene-based multi-stage polymer obtained by polymerizing the components constituting the propylene-based polymer in two or more stages. The combination of the components constituting the propylene-based polymer may be between propylene homopolymer components, between a propylene homopolymer component and a propylene copolymer component, or between propylene copolymer components. When at least two propylene-based polymer components are polymerized in multiple stages, the propylene-based multi-stage polymer is a propylene-based polymer composition containing at least two propylene-based polymer components.

[0026] In one aspect, preferably, the propylene-based polymer contains a polymer component A containing 95% by mass or more of a structural unit derived from propylene, and a polymer component B containing 50% by mass or more and 85% by mass or less of a structural unit derived from propylene, and 15% by mass or more and 50% by mass or less of a structural unit derived from one or more selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms.

[0027] The content of the structural unit derived from propylene contained in the polymer component A is preferably 95% by mass or more, more preferably 100%, that is, a propylene homopolymer. The content of the structural unit derived from one or more selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms contained in the polymer component B is preferably 10% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 40% by mass or less.

[0028] Based on the total of 100% by mass of the content of polymer component A and the content of polymer component B, the content of polymer component A is preferably 50% by mass or more and 85% by mass or less, more preferably 65% by mass or more and 85% by mass or less. Also, the content of polymer component B is preferably 15% by mass or more and 50% by mass or less, more preferably 15% by mass or more and 35% by mass or less.

[0029] <Ethylene-based polymer> The ethylene-based polymer is a polymer containing more than 50% by mass of structural units derived from ethylene, that is, a homopolymer of ethylene or an ethylene-based copolymer containing more than 50% by mass of structural units derived from ethylene. Examples of the structural units other than ethylene contained in the ethylene-based copolymer include structural units derived from α-olefins having 4 to 12 carbon atoms.

[0030] When the ethylene-based polymer is an ethylene-based copolymer, it preferably contains 65% by mass or more and 98% by mass or less, more preferably 75% by mass or more and 95% by mass or less of the structural units derived from ethylene. Also, it preferably contains 2% by mass or more and 35% by mass or less, more preferably 5% by mass or more and 25% by mass or less of the structural units derived from α-olefins having 4 to 12 carbon atoms.

[0031] The density of the ethylene-based polymer is preferably 860 kg / m 3 or more and 930 kg / m 3 or less, more preferably 880 kg / m 3 or more and 930 kg / m 3 or less. By having the density of the ethylene-based polymer be 860 kg / m 3 or more, a film excellent in rigidity can be obtained. Also, by having the density of the ethylene-based polymer be 930 kg / m 3 or less, a film excellent in impact resistance at low temperatures can be obtained. The density is measured according to Method A specified in JIS K7112-1980.

[0032] The ethylene-based polymer, in one aspect, preferably contains 65% by mass or more and 98% by mass or less of structural units derived from ethylene, and 2% by mass or more and 35% by mass or less of structural units derived from α-olefins having 4 to 12 carbon atoms, and has a density of 860 kg / m 3 or more and 930 kg / m 3 or less.

[0033] The melt flow rate (MFR) of the ethylene-based polymer, measured at a temperature of 190 °C and a load of 2.16 kg, is preferably 0.5 g / 10 min or more and 30 g / 10 min or less, more preferably 0.5 g / 10 min or more and 10 g / 10 min or less, and even more preferably 1 g / 10 min or more and 5 g / 10 min or less. When the MFR is 0.5 g / 10 min or more, it is possible to suppress the generation of fine irregularities (so-called "yuzu skin") on the surface of the film. Also, when the MFR is 30 g / 10 min or less, the heat sealability of the film can be made good. The MFR of the ethylene-based polymer is measured according to Method A specified in JIS K7210-1.

[0034] The ethylene homopolymer is preferably produced by the so-called "high-pressure method". The production of the ethylene homopolymer by the "high-pressure method" is generally carried out by polymerizing ethylene at a polymerization pressure of 140 to 300 MPa and a polymerization temperature of 200 to 300 °C in the presence of a radical generator using a tank reactor or a tubular reactor.

[0035] Examples of the production method of the ethylene-based copolymer include production methods by known polymerization methods using known radical polymerization catalysts or ionic polymerization catalysts. Examples of known catalysts include peroxide catalysts, Ziegler-Natta catalysts, metallocene catalysts, etc. Examples of known polymerization methods include solution polymerization method, slurry polymerization method, high-pressure ionic polymerization method, high-pressure radical polymerization method, gas-phase polymerization method, etc.

[0036] In the film according to this embodiment, with respect to a total of 100% by mass of the content of the propylene-based polymer and the content of the ethylene-based polymer, the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, preferably 70% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 95% by mass or less. Also, the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less, preferably 5% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 25% by mass or less.

[0037] Also, when the film according to this embodiment contains two or more types of propylene-based polymers, and at least one type of propylene-based polymer is a propylene homopolymer or a propylene-based random copolymer, and at least one other type of propylene-based polymer is a propylene-based multi-stage polymer, with respect to a total of 100% by mass of the content of the propylene-based polymer and the content of the ethylene-based polymer, the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, preferably 70% by mass or more and 95% by mass or less, and more preferably 75% by mass or more and 95% by mass or less. Also, the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less, preferably 5% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 25% by mass or less.

[0038] <Other Components> The film according to this embodiment may contain other components such as additives and other resins, as necessary, as long as the object and effects of the present invention are not impaired. Note that the other components may be mixed in advance with the propylene-based polymer to form a pellet-like propylene-based polymer composition.

[0039] Examples of the additives include antioxidants, neutralizing agents, ultraviolet absorbers, antistatic agents, lubricants, nucleating agents, adhesives, antifogging agents, antiblocking agents, melt flow rate regulators, and the like. Examples of the other resins include styrene-butadiene-styrene copolymers, styrene-isoprene-styrene copolymers, and hydrogenated products of these copolymers.

[0040] An antioxidant is a compound having the function of preventing the decomposition of polyolefin resins due to heat, light, oxygen, etc. Examples of antioxidants include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, hydroxylamine antioxidants, and metal deactivators. Preferably, they are phenolic antioxidants, phosphorus antioxidants, or sulfur antioxidants.

[0041] Examples of phenolic antioxidants include 2,6-di-tert-butyl-4-methylphenol, tetrakis[methylene-3(3’,5’-di-tert-butyl-4-hydroxyphenyl)propionate]methane, octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 3,9-bis[2-{3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5·5]undecane, 1,3,5-tris2[3(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxy]ethyl isocyanate, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, pentaerythrityl-tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], triethylene glycol-N-bis-3-(3-tert-butyl-5-methyl-4-hydroxyphenyl)propionate, 1,6-hexanediol bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2-thiobis-diethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2,2’-methylene-bis-(4-methyl-6-tert-butylphenol), 2,2’-methylene-bis-(4-ethyl-6-tert-butylphenol), 2,2’-methylene-bis-(4,6-di-tert-butylphenol), 2,2’-ethylidene-bis-(4,6-di-tert-butylphenol), 2,2’-butylidene-bis-(4-methyl-6-tert-butylphenol), 4,4’-butylidenebis(3-methyl-6-tert-butylphenol), 2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphenyl acrylate, 2,4-di-tert-amyl-6-(1-(3,Examples include 5 - di - tert - amyl - 2 - hydroxyphenyl)ethyl)phenyl acrylate and tocopherols. Examples of tocopherols include vitamin E, which is α - tocopherol. Preferably, they are 2,6 - di - tert - butyl - 4 - methylphenol, tetrakis[methylene - 3(3’,5’ - di - tert - butyl - 4 - hydroxyphenyl)propionate]methane, 2,6 - di - tert - butyl - 4 - methylphenol, octadecyl - 3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate, 3,9 - bis[2 - {3 - (3 - tert - butyl - 4 - hydroxy - 5 - methylphenyl)propionyloxy}-1,1 - dimethylethyl]-2,4,8,10 - tetraoxaspiro[5·5]undecane, tris(3,5 - di - tert - butyl - 4 - hydroxybenzyl)isocyanurate or vitamin E. More preferably, they are tetrakis[methylene - 3(3’,5’ - di - tert - butyl - 4 - hydroxyphenyl)propionate]methane, octadecyl - 3 - (3,5 - di - tert - butyl - 4 - hydroxyphenyl)propionate or vitamin E.

[0042] The content of the phenolic antioxidant is usually 0.01 part by mass or more and 2 parts by mass or less, preferably 0.01 part by mass or more and 1 part by mass or less, and more preferably 0.01 part by mass or more and 0.5 part by mass or less, based on 100 parts by mass of the total mass of the film.

[0043] Examples of phosphorus-based antioxidants include tris(nonylphenyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite, bis(2,4-di-tert-butyl-6-methylphenyl) pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, bis(2,4-dicumylphenyl) pentaerythritol diphosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-diphenylenediphosphonite, 2,2'-methylenebis(4,6-di-tert-butylphenyl) 2-ethylhexyl phosphite, 2,2'-ethylidenebis(4,6-di-tert-butylphenyl) fluorophosphite, bis(2,4-di-tert-butyl-6-methylphenyl) ethyl phosphite, 2-(2,4,6-tri-tert-butylphenyl)-5-ethyl-5-butyl-1,3,2-oxaphospholane, 2,2',2''-nitrilo[triethyl-tris(3,3',5,5'-tetra-tert-butyl-1,1'-biphenyl-2,2'-diyl) phosphite, 2,4,8,10-tetra-tert-butyl-6-[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propoxy]dibenz[d,f][1,3,2]dioxaphosphepine. Preferably, tris(2,4-di-tert-butylphenyl) phosphite or 2,4,8,10-tetra-tert-butyl-6-[3-(3-methyl-4-hydroxy-5-tert-butylphenyl)propoxy]dibenz[d,f][1,3,2]dioxaphosphepine is used.

[0044] The content of the phosphorus-based antioxidant is usually 0.01 part by mass or more and 2 parts by mass or less, preferably 0.01 part by mass or more and 1 part by mass or less, and more preferably 0.01 part by mass or more and 0.5 part by mass or less, based on 100 parts by mass of the total mass of the film.

[0045] Examples of the sulfur-based antioxidant include dilauryl 3,3'-thiodipropionate, tridecyl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, lauryl stearyl 3,3'-thiodipropionate, neopentanetetrayl tetrakis(3-laurylthiopropionate), bis[2-methyl-4-(3-n-alkyl (C12-C14) thiopropionyloxy)-5-tert-butylphenyl] sulfide. Preferably, they are dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate or distearyl 3,3'-thiodipropionate.

[0046] The content of the sulfur-based antioxidant is usually 0.01 part by mass or more and 2 parts by mass or less, preferably 0.01 part by mass or more and 1 part by mass or less, and more preferably 0.01 part by mass or more and 0.5 part by mass or less with respect to 100 parts by mass of the total mass of the film.

[0047] Examples of the neutralizing agent include calcium stearate, hydrotalcite, oxides of alkaline earth metals, and hydroxides of alkaline earth metals. These neutralizing agents may be used alone or in combination of two or more.

[0048] Examples of the other additives include lubricants typified by higher fatty acid amides and higher fatty acid esters; antistatic agents such as glycerin esters of fatty acids having 8 to 22 carbon atoms, sorbitan acid esters, and polyethylene glycol esters; antiblocking agents typified by synthetic silica powder, synthetic aluminosilicate powder, polymer beads, and silicone resin compounds; and antifogging agents typified by glycerin fatty acid esters, polyglycerin fatty acid esters, polyethylene glycol fatty acid esters, polyethylene glycol sorbitan fatty acid esters, polyoxyethylene alkyl ethers, sorbitan fatty acid esters, alkyldiethanolamine, and alkyldiethanolamide.

[0049] <Lamellar orientation index> The film according to this embodiment has a lamellar orientation index in the direction of the film flow (MD) in the region from at least one film surface to a depth of 10 μm of 1.20 or more and 3.20 or less, preferably 1.20 or more and 2.00 or less. The propylene-based polymer forms a crystal structure of an oriented phase or a spherulite phase in the film. When the lamellar orientation index is within the above range, an appropriately oriented phase of the propylene-based polymer exists in the film. As a result, the film has relatively excellent heat sealability.

[0050] As a method for adjusting the lamellar orientation index within the above range, in the film manufacturing method described later, there is a method of adjusting the melt kneading temperature, screw rotation speed, extrusion amount, extrusion temperature, cooling temperature, and film forming speed within a predetermined range. By adjusting these manufacturing conditions within a predetermined range, the balance between the oriented phase and the spherulite phase in the propylene-based polymer can be controlled, and as a result, the lamellar orientation index can be adjusted within the above range.

[0051] The lamellar orientation index is measured by the small-angle X-ray scattering method. Specific measurement procedures will be described with reference to FIGS. 1 to 10.

[0052] (Measurement sample) A thin slice for performing measurement by the small-angle X-ray scattering method is cut out from the film, and the cut-out thin slice is used as the measurement sample.

[0053] (Preparation of thin slice) As shown in FIG. 1, a part of the film 11 is cut using a trimming knife or the like (the dotted line part in FIG. 1) to obtain the section 21 shown in FIG. 2. As shown in FIG. 2, a part of the section 21 is cut using a slicer or the like (the dotted line part in FIG. 2) to obtain the thin slice 31 shown in FIG. 3.

[0054] Hereinafter, the thickness direction (ND) of the thin slice 31 is referred to as the A direction, the flow direction (MD) of the film is referred to as the B direction, and the width direction (TD) of the film is referred to as the C direction (see FIG. 3).

[0055] The size of the thin slice 31 is 5 to 10 mm in the B direction and the thickness through which X-rays penetrate (usually 100 μm) in the C direction. Note that in the A direction, it is the same as the film thickness.

[0056] (Small-angle X-ray measurement) As shown in FIGS. 4 and 5, in the thin slice 31, small-angle X-ray measurement is performed on the region from the film surface (that is, the surface along the B direction in FIGS. 4 and 5) to a depth of 10 μm. As the X-rays, those with a beam diameter of 10 μm or less are used. As shown in FIG. 4, when the beam diameter 42 of the X-rays is 5 to 10 μm, the measurement is performed with the center of the beam aligned with the position 5 μm deep from the film surface of the thin slice 31. As shown in FIG. 5, when the beam diameter 52 of the X-rays is less than 5 μm, the measurement is performed while scanning the X-rays along the A direction from the film surface of the thin slice 31 at intervals 53 of the beam diameter 52. The number of measurements satisfies the following formula (12). When the beam diameter 52 of the X-rays is less than 5 μm, since a plurality of two-dimensional scattering images are obtained, the average value of the lamellar orientation indices calculated from each two-dimensional scattering image is used. X-ray beam diameter × number of measurements ≤ 10 μm < X-ray beam diameter × (number of measurements + 1) (12)

[0057] Since the X-ray source has a small beam diameter, its scattering intensity is low. Therefore, as the X-ray source, synchrotron radiation X-rays are used so that a sufficient signal / noise ratio can be obtained. The exposure time of the X-rays may be adjusted so that a sufficient signal / noise ratio can be obtained.

[0058] (Installation of the thin slice) As shown in FIG. 6, the thin slice 31 is installed at the position where X-rays are irradiated from the X-ray source 61, and the detector 63 is installed behind the thin slice 31. Measurement is performed by the small-angle X-ray scattering method to obtain a two-dimensional scattering image. In the obtained two-dimensional scattering image, the direction parallel to the A direction of the thin slice 31 is called the X direction, and the direction parallel to the B direction of the thin slice is called the Y direction.

[0059] (Calculation method of the lamellar orientation index) The lamellar orientation index is calculated from the obtained two-dimensional scattering image according to the following procedure.

[0060] Figure 7 shows an example of the obtained two-dimensional scattering image. Let the scattering intensity in the obtained two-dimensional scattering image be I(q), and the profile cut out in the Y direction from the center of the two-dimensional scattering image be the q-profile (see Figure 8).

[0061] q is calculated by the following formula (13). q = 4πsinθ / λ (13) (In the formula, π represents the ratio of the circumference of a circle to its diameter, θ represents half of the scattering angle, and λ represents the wavelength (nm) of the X-ray.)

[0062] (Calculation of qmax) When the signal / noise ratio of the above q-profile is not sufficient (3 or less), it is preferable to perform averaging in the circumferential direction within the range of ±45° or less. The signal / noise ratio is preferably 5 or more. The obtained q-profile is subjected to a Kratky plot, and the position q at which I(q)×q 2 is maximum is defined as qmax (see Figure 9). The method of the Kratky plot is disclosed, for example, in "Radiation Light Nov. 2006 Vol.19 No.6".

[0063] (Creation of azimuthal profile) An azimuthal profile is obtained by plotting the scattering intensity with respect to the azimuthal angle at a position separated from the center by qmax (see Figure 10). In the azimuthal profile, the points parallel to the direction Y are set as 0° and 180°. Let the scattering intensity at 180° be I(180°) and the scattering intensity at 135° be I(135°), and the lamellar orientation index (H) is calculated by the following formula (14). H = I(180°) / I(135°) (14)

[0064] The Kratky plot and the azimuthal profile are subjected to processing such as smoothing as necessary. Examples of the processing such as smoothing include adjacent averaging.

[0065] In the film according to this embodiment, the thickness is preferably 30 μm or more and 200 μm or less, and more preferably 50 μm or more and 100 μm or less.

[0066] The film according to this embodiment may be used by being laminated with other films. Examples of other films include biaxially oriented polypropylene films, oriented nylon films, oriented polyethylene terephthalate films, and aluminum foils. Examples of methods for laminating the film according to this embodiment with other films include the dry lamination method and the extrusion lamination method.

[0067] Also, the film according to this embodiment can be used as a material for a packaging bag formed in a bag shape for containing contents. Such a packaging bag may contain, for example, liquid substances such as shampoo, conditioner, soy sauce, and pot sauce, may contain powdery substances such as salt and sugar, or may contain retort foods.

[0068] [Method for manufacturing the film] In the method for manufacturing the film according to this embodiment, a propylene-based polymer containing more than 50% by mass of structural units derived from propylene and an ethylene-based polymer containing more than 50% by mass of structural units derived from ethylene are contained. With respect to a total of 100% by mass of the content of the propylene-based polymer and the content of the ethylene-based polymer, the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, and the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less. A step (1) of melt-kneading the resin composition under the condition of 200°C or higher and 350°C or lower, and a step of extruding the melt-kneaded resin composition from a T-die using an extruder equipped with a screw as a resin composition for forming the surface layer portion of the film. The step (2) of extruding under the conditions of screw rotation speed: 20 rpm or more and 200 rpm or less, extrusion amount: 10 kg / hour or more and 500 kg / hour or less, and extrusion temperature of the T-die: T1°C, and a step (3) of forming the film under the conditions of cooling temperature: T2°C and film forming speed: 10 m / minute or more and less than 70 m / minute.

[0069] In the method for manufacturing a film according to this embodiment, as shown in FIG. 11, a film forming machine 10 having an extruder 101 equipped with a screw 1a is used. Specifically, an extruder 101 that extrudes a melt-kneaded resin composition, a feed block 102 that is a confluence portion of the resin compositions extruded from each extruder 101 when a plurality of extruders 101 are used, a T-die 103 that extrudes the resin composition supplied from the feed block 102 into a sheet shape, and a plurality of cooling rolls 104 that cool the sheet-shaped resin composition supplied from the T-die 103 are provided. The film forming machine 10 is used.

[0070] The diameter (D; the diameter of the blade portion formed in a spiral shape) of the screw 1a is preferably 40 mm or more and 200 mm or less, more preferably 50 mm or more and 200 mm or less. Further, the length (L) of the screw 1a is preferably 800 mm or more and 6000 mm or less. The ratio (L / D) of the length of the screw 1a to the diameter of the screw 1a is preferably 15 or more and 40 or less, more preferably 20 or more and 35 or less. In the extruder 101, at least one screw 1a may be provided, or a plurality of screws 1a may be provided.

[0071] <Step (1)> In step (1), a resin composition containing a propylene-based polymer and an ethylene-based polymer is melt-kneaded. Melt-kneading means kneading the resin composition in a molten state. Specifically, the molten resin composition is kneaded by the rotation of the screw 1a in the extruder 101. Then, while kneading the molten resin composition by the rotation of the screw 1a, it is conveyed toward the outlet side of the extruder 101.

[0072] The resin composition supplied to the extruder 101 contains the above-mentioned propylene-based polymer and the above-mentioned ethylene-based polymer. The content of the propylene-based polymer and the content of the ethylene-based polymer can also be within the above-mentioned ranges. The resin composition supplied to the extruder 101 may be in a pre-melted state or in a state before melting (pellet form). When supplying pre-melted pellets to the extruder 101, the pellets are melted within the extruder 101.

[0073] The melt-kneading temperature is 200°C or higher and 350°C or lower, preferably 220°C or higher and 300°C or lower. By performing step (1) under the condition that the melt-kneading temperature is within the above range, a film with relatively excellent heat-sealing properties can be obtained. The extruder 101 may be provided with heating means (not shown) such as a heater so that the molten state of the supplied resin composition is maintained. The heating means is configured to heat the resin composition to the above-mentioned melt-kneading temperature.

[0074] <Step (2)> In step (2), the resin composition melt-kneaded in step (1) is extruded from the T-die 103 using the extruder 101 equipped with the screw 1a as the resin composition for forming the surface layer portion of the film. Specifically, by continuously conveying the resin composition by the rotation of the screw 1a, the resin composition is extruded from the outlet of the extruder 101.

[0075] The rotation speed of the screw 1a is 20 rpm or higher and 200 rpm or lower, preferably 40 rpm or higher and 150 rpm or lower. By performing step (2) under the condition that the rotation speed of the screw 1a is within the above range, a film with relatively excellent heat-sealing properties can be obtained.

[0076] The extrusion rate is 10 kg / h or higher and 500 kg / h or lower, preferably 70 kg / h or higher and 500 kg / h or lower. By performing step (2) under the condition that the extrusion rate is within the above range, a film with relatively excellent heat-sealing properties can be obtained.

[0077] The extrusion temperature T1 of the T-die 103 is preferably 220°C or higher and 300°C or lower, more preferably 230°C or higher and 280°C or lower. Note that the extrusion temperature T1 of the T-die 103 is the temperature of the T-die 103 itself.

[0078] The outlet pressure of the extruder 101 is preferably 10 Mpa or higher and 35 Mpa or lower, more preferably 15 Mpa or higher and 30 Mpa or lower. Note that the outlet pressure is the pressure applied to the molten resin near the outlet of the extruder 101. Examples of the method for measuring the outlet pressure include a method of installing a pressure gauge near the outlet of the extruder 101 for measurement.

[0079] <Process (3)> In process (3), the resin composition extruded in process (2) is formed into a film. Specifically, the resin composition extruded from the extruder 101 is supplied to the T-die 103 via the feed block 102. Then, by discharging the resin composition extruded from the extruder 101 from the T-die 103, a film is formed to a predetermined thickness. The formed resin composition is cooled by contacting the cooling roll 104, and the film F is formed.

[0080] The film forming speed is 10 m / min or higher and less than 70 m / min, preferably 30 m / min or higher and 60 m / min or lower. By performing process (3) under the conditions within the above range of the film forming speed, a film with relatively excellent heat sealability can be obtained.

[0081] The formed resin composition is preferably formed to a thickness of 30 μm or higher and 200 μm or lower, more preferably 50 μm or higher and 100 μm or lower.

[0082] The cooling temperature T2 of the cooling roll 104 is preferably 20°C or higher and 60°C or lower, more preferably 20°C or higher and 50°C or lower. Note that the cooling temperature T2 of the cooling roll 104 is the temperature of the cooling roll 104 itself.

[0083] The extrusion temperature T1 of the T-die 103 and the cooling temperature T2 of the cooling roll 104 satisfy the following formula (11). With such a configuration, a film having relatively excellent heat sealability can be obtained. 180 ≦ T1 - T2 ≦ 250 (11)

[0084] Note that the film and the method for manufacturing the film according to the present embodiment are not limited to the above embodiment, and various modifications are possible without departing from the gist of the present invention. Further, the configurations and methods of the embodiments other than the above may be arbitrarily adopted and combined, or the configurations and methods according to one of the above embodiments may be applied to the configurations and methods according to the other embodiments above.

Examples

[0085] Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[0086] <Propylene-based polymer composition (1)> As a first step, propylene was polymerized by a gas-phase polymerization method using a Ziegler-Natta type catalyst. Then, as a second step, in the presence of the obtained propylene homopolymer, propylene and ethylene were copolymerized by a gas-phase polymerization method to obtain a propylene-based multi-stage polymer. The obtained propylene-based multi-stage polymer had a content of propylene homopolymer (polymer component A) of 77% by mass and a content of propylene-ethylene copolymer (polymer component B) of 23% by mass. Further, the content of the structural unit derived from ethylene in the polymer component B was 30% by mass. 100 parts by mass of the obtained propylene-based multistage polymer, 0.005 parts by mass of calcium hydroxide, 0.075 parts by mass of Sumilizer GP (2,4,8,10-tetra-t-butyl-6-[3-(3-methyl-4-hydroxy-5-t-butylphenyl)propoxy]dibenzod[f][1,3,2]dioxaphosphepine, manufactured by Sumitomo Chemical Co., Ltd.), 0.03 parts by mass of Sumilizer GS (2,4-di-t-amyl-6-[1-(3,5-di-t-amyl-2-hydroxyphenyl)ethyl]phenyl acrylate, manufactured by Sumitomo Chemical Co., Ltd.), and an appropriate amount of a melt flow rate regulator (2,5-dimethyl-2,5-di(tert-butylperoxy)hexane) were mixed with a Henschel mixer and then melt-extruded to obtain a pelletized propylene-based polymer composition (1). The obtained propylene-based polymer composition (1) had a melt flow rate of 3 g / 10 min as measured at 230°C.

[0087] In addition, the contents of polymer component A and polymer component B in the propylene-based multistage polymer are those obtained from the material balance during the polymerization of polymer component A and polymer component B.

[0088] The melt flow rate (MFR) of the propylene-based polymer composition (1) was measured at a temperature of 230°C and a load of 2.16 kg in accordance with Method A specified in JIS K7210-1.

[0089] In polymer component B of the propylene-based multistage polymer, the content of the structural unit derived from ethylene was calculated by the following formula (15) in accordance with the method for block copolymers described on page 616 of the Polymer Analysis Handbook (published by Kinokuniya Bookstore in 1995) by performing an overall IR spectrum measurement of the propylene-based polymer composition (1). E B =(E T -E A ×P A ) / P B (15) (In the formula, E T , E A and E Brepresents the content of the structural unit derived from ethylene in the propylene-based polymer composition (1), polymer component A, and polymer component B, respectively, where P A and P B represent the contents of polymer component A and polymer component B, respectively.)

[0090] <Ethylene-based polymer (1)> As the ethylene-based polymer (1), an ethylene-butene-1 copolymer (Tafmer A4085s, manufactured by Mitsui Chemicals, Inc.) was used. The ethylene-based polymer has a content of the structural unit derived from ethylene of 80% by mass and a content of the structural unit derived from 1-butene of 20% by mass, a melt flow rate measured at 190 °C of 3.6 g / 10 min, and a density of 885 kg / m 3 It was as follows.)

[0091] The melt flow rate (MFR) of the ethylene-based polymer was measured according to Method A specified in JIS K7210-1 at a temperature of 190 °C and a load of 2.16 kg.)

[0092] The density of the ethylene-based polymer was measured according to Method A specified in JIS K7112-1980. The sample was annealed as described in JIS K6760-1995.)

[0093] <Film forming machine 1> In the film forming machine 10 shown in Fig. 11, one extruder 101 was used. The extruder 101 was connected to a T-die 103 via a feed block 102. The molten resin extruded from the T-die 103 was cooled and solidified by a cooling roll 104 and then wound up. The diameter (D) of the screw 1a in the extruder 101 was 50 mm, the length (L) was 1600 mm, and L / D was 32. The die width of the T-die 103 was 400 mm, and the lip opening was 0.8 mm.)

[0094] <Film forming machine 2> In the film forming machine 10 shown in Fig. 11, the extruder 101 consists of a total of three extruders: one main extruder for extruding the resin composition for forming the intermediate portion of the film and two satellite extruders for extruding the resin composition for forming the surface layer portion of the film. The three extruders 101 are connected to the T-die 103 via the feed block 102, and a film forming machine is used in which the molten resin extruded from the T-die 103 is cooled and solidified by the cooling roll 104 and then wound up. Among the three extruders, the diameter (D) of the screw 1a of the one main extruder is 90 mm, the length (L) is 2970 mm, the L / D is 33, and the diameter (D) of the screws 1a of the two satellite extruders is 65 mm, the length (L) is 1885 mm, and the L / D is 29. The die width of the T-die 103 was 1250 mm, and the lip opening was 0.8 mm.

[0095] <Example 1> A resin composition obtained by pellet blending 90% by mass of the propylene-based polymer composition (1) and 10% by mass of the ethylene-based polymer (1) was supplied to the film forming machine 1 to obtain a sealant film having a thickness of 70 μm. The rotational speed of the screw 1a in the film forming machine 1 was 50 rpm, the melt kneading temperature was 270 °C, the extrusion temperature T1 of the T-die 103 was 250 °C, the cooling temperature T2 of the cooling roll 104 was 50 °C, and the film forming speed was 10 m / min. The extrusion amount of the molten resin extruded from the T-die 103 was 13 kg / h. The film forming conditions are shown in Table 1.

[0096] <Example 2> A sealant film having a thickness of 70 μm was obtained in the same manner as in Example 1, except that the rotational speed of the screw 1a in the film forming machine 1 was 80 rpm and the film forming speed was 20 m / min. The extrusion amount of the molten resin extruded from the T-die 103 was 27 kg / h. The film forming conditions are shown in Table 1.

[0097] <Example 3> A sealant film having a thickness of 70 μm was obtained in the same manner as in Example 1, except that the cooling temperature T2 of the cooling roll 104 in the film forming machine 1 was 20 °C. The extrusion amount of the molten resin extruded from the T-die 103 was 13 kg / h. The film forming conditions are shown in Table 1.

[0098] <Example 4> A sealant film with a thickness of 70 μm was obtained in the same manner as in Example 1, except that the extrusion temperature T1 of the T-die 103 in the film forming machine 1 was set to 280°C. The extrusion rate of the molten resin extruded from the T-die 103 was 13 kg / h. The film forming conditions are shown in Table 1.

[0099] <Comparative Example 1> A sealant film with a thickness of 70 μm was obtained in the same manner as in Example 4, except that the rotation speed of the screw 1a in the film forming machine 1 was 10 rpm, the film forming speed was 3 m / min, and the cooling temperature T2 of the cooling roll 104 was 20°C. The extrusion rate of the molten resin extruded from the T-die 103 was 4 kg / h. The film forming conditions are shown in Table 1.

[0100] <Comparative Example 2> A sealant film with a thickness of 70 μm was obtained in the same manner as in Example 4, except that the cooling temperature T2 of the cooling roll 104 in the film forming machine 1 was 20°C. The extrusion rate of the molten resin extruded from the T-die 103 was 13 kg / h. The film forming conditions are shown in Table 1.

[0101]

Table 1

[0102] <Example 5> A resin composition obtained by pellet blending 90% by mass of the propylene-based polymer composition (1) and 10% by mass of the ethylene-based polymer (1) was supplied to the film forming machine 2 to obtain a sealant film with a thickness of 70 μm. In the film forming machine 2, the rotation speed of the screw 1a of the main extruder was 22 rpm, the melt kneading temperature was 260°C, the rotation speed of the screw 1a of the satellite extruder was 25 rpm, the melt kneading temperature was 260°C, the extrusion temperature T1 of the T-die 103 was 250°C, the cooling temperature T2 of the cooling roll 104 was 50°C, and the film forming speed was 20 m / min. The extrusion rate of the molten resin extruded from the T-die 103 was 76 kg / h. The film forming conditions are shown in Table 2.

[0103] <Example 6> Except that the rotation speed of the screw 1a of the main extruder in the film forming machine 2 was set to 65 rpm, the rotation speed of the screw 1a of the satellite extruder was set to 92 rpm, and the film forming speed was set to 50 m / min, a sealant film with a thickness of 70 μm was obtained in the same manner as in Example 5. The extrusion amount of the molten resin extruded from the T-die 103 was 210 kg / h. The film forming conditions are shown in Table 2.

[0104] <Example 7> Except that the rotation speed of the screw 1a of the main extruder in the film forming machine 2 was set to 65 rpm, the rotation speed of the screw 1a of the satellite extruder was set to 154 rpm, and the film forming speed was set to 66 m / min, a sealant film with a thickness of 70 μm was obtained in the same manner as in Example 5. The extrusion amount of the molten resin extruded from the T-die 103 was 272 kg / h. The film forming conditions are shown in Table 2.

[0105] <Comparative Example 3> Except that the rotation speed of the screw 1a of the main extruder in the film forming machine 2 was set to 53 rpm, the rotation speed of the screw 1a of the satellite extruder was set to 80 rpm, the film forming speed was set to 50 m / min, and the cooling temperature T2 of the cooling roll 104 was set to 80°C, a sealant film with a thickness of 70 μm was obtained in the same manner as in Example 5. The extrusion amount of the molten resin extruded from the T-die 103 was 179 kg / h. The film forming conditions are shown in Table 2.

[0106] <Comparative Example 4> Except that the rotation speed of the screw 1a of the main extruder in the film forming machine 2 was set to 57 rpm, the rotation speed of the screw 1a of the satellite extruder was set to 133 rpm, the film forming speed was set to 65 m / min, and the cooling temperature T2 of the cooling roll 104 was set to 80°C, a sealant film with a thickness of 70 μm was obtained in the same manner as in Example 5. The extrusion amount of the molten resin extruded from the T-die 103 was 239 kg / h. The film forming conditions are shown in Table 2.

[0107]

Table 2

[0108] <Measurement of lamellar orientation index> The lamellar orientation index in the region from the surface to a depth of 10 μm of the sealant film was measured by the following method.

[0109] <Preparation of Measurement Sample (Thin Film)> From the sealant film, using a slicer, a thin film with dimensions of 70 μm in the above-mentioned A direction, 10 mm in the B direction, and 100 μm in the C direction was cut out and used as the measurement sample.

[0110] The measurement by the small-angle X-ray scattering method was carried out under the following conditions using the dedicated polymer beamline BL03XU installed at the large synchrotron radiation facility SPring-8 (Hyogo Prefecture). · X-ray wavelength: 0.1 nm · X-ray beam diameter: 2 μm · Standard sample for camera length calibration: silver behenate · Distance between the thin film and the detector: 1 m · Detector: 2D semiconductor X-ray detector PILATUS (manufactured by Rigaku, pixel size 172 μm) · Measurement range: scattering vector q = 0.01 nm -1 ~2 nm -1 · Scanning direction of X-ray: A direction of the thin film · Scanning interval of X-ray: 2 μm · Number of measurement points: 50 points · Exposure time: 3 seconds · The 2D scattering image obtained by the small-angle X-ray measurement was corrected using the 2D scattering image (air blank) obtained without installing the measurement sample.

[0111] From the corrected scattering image, a q profile in the range of ±45° in the Y direction was obtained, a Kratky plot was performed, and qmax was calculated. Based on the azimuthal profile at qmax, the lamellar orientation index was calculated using the above-mentioned formula (ii). The average value of the lamellar orientation indices of 5 points was taken as the lamellar orientation index. The measurement results are shown in Table 3.

[0112] <Composite Film> A sealant film, an aluminum foil (thickness 7 μm), and a polyethylene terephthalate film (thickness 12 μm) were laminated in this order by the dry lamination method to obtain a composite film.

[0113] <Heat seal strength> Using a heat sealer manufactured by Toyo Tester Kogyo Co., Ltd., two composite films were overlapped so that the sealant film side was on the inside, and heat sealing was performed in a strip shape under the following conditions so that the direction perpendicular to the flow direction (MD) of the sealant film and the direction of the seal bar were aligned. · Seal bar: Plane double-sided heating · Seal temperature: 200 °C · Seal pressure: 1.0 kg / cm 2 · Seal time: 1.0 sec · Seal width: 10 mm

[0114] From the heat-sealed composite film, a test piece with a width of 15 mm in the direction perpendicular to the seal width direction was cut out. Using a tensile testing machine (Tensilon manufactured by Orientec), the test piece was peeled under the conditions of a peel angle of 90° and a tensile speed of 200 mm / min, and the maximum value of the peel strength was defined as the heat seal strength. The measurement results are shown in Table 3.

[0115]

Table 3

[0116] As can be seen from the results in Table 3, the films of each example that satisfy all the constituent requirements of the present invention have higher heat seal strength than the films of each comparative example, that is, they are excellent in heat sealability.

Explanation of symbols

[0117] 11, F film 21 section 31 slice 42, 52 beam diameter 53 scanning interval 61 X-ray source 63 Detector 1a Screw 10 Film Coating Machine 101 Extruder 102 Feed Block 103 T-Die 104 Cooling Roll

Claims

1. A film containing a propylene-based polymer containing more than 50% by mass of structural units derived from propylene and an ethylene-based polymer containing more than 50% by mass of structural units derived from ethylene, wherein the content of the propylene-based polymer is 50% by mass or more and 95% by mass or less, and the content of the ethylene-based polymer is 5% by mass or more and 50% by mass or less, based on a total of 100% by mass of the content of the propylene-based polymer and the content of the ethylene-based polymer, and having a lamellar orientation index in the flow direction (MD) of the film in the region from the surface of at least one film surface to a depth of 10 μm of 1.20 or more and 1.83 or less.

2. The propylene-based polymer is a polymer component A containing 95% by mass or more of structural units derived from propylene, a polymer component B containing 50% by mass or more and 85% by mass or less of structural units derived from propylene and 15% by mass or more and 50% by mass or less of structural units derived from one or more selected from the group consisting of ethylene and α-olefins having 4 to 12 carbon atoms, The film according to claim 1, wherein the content of the polymer component A is 50% by mass or more and 85% by mass or less, and the content of the polymer component B is 15% by mass or more and 50% by mass or less, based on a total of 100% by mass of the content of the polymer component A and the content of the polymer component B.

3. The ethylene-based polymer is contains 65% by mass or more and 98% by mass or less of structural units derived from ethylene and 2% by mass or more and 35% by mass or less of structural units derived from α-olefins having 4 to 12 carbon atoms, The density is 860 kg / m ３ or more and 930 kg / m ３ or less. The film according to claim 1 or 2.

4. The film according to any one of claims 1 to 3, having a thickness of 30 μm or more and 200 μm or less.

Images