Films, laminates, and packaging materials.

Abstract

Provided is a film containing an ethylene polymer satisfying the following requirements (a1) to (a4): (a1) having a density of 940-980 kg / m3; (a2) having a melt flow rate (MFR) of 0.01-10 g / 10 min as measured at 190°C under a load of 2.16 kg; (a3) containing 300 ppm or less of a low molecular weight component; and (a4) having a ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (molecular weight distribution: Mw / Mn) of 10 or less as measured by gel permeation chromatography (GPC).

Description

Films, laminates and packaging materials

[0001] The present invention relates to films, laminates and packaging materials.

[0002] In recent years, against the backdrop of environmental issues, laws regarding the disposal of various plastics have been enacted, and there is an increasing need to recycle packaging materials, and various recyclable packaging materials have been studied (see, for example, Patent Documents 1 and 2). Among these, mono-material materials made of a single material (for example, all PE) have attracted attention as recyclable packaging materials.

[0003] Films made from various resins are commonly used as base materials for packaging materials, but properties required for an all-PE base material include heat resistance. From the standpoint of heat resistance, high-density polyethylene (HDPE) is a suitable resin, but the use of HDPE has issues such as poor transparency and the generation of white powder, which is thought to be derived from low-molecular-weight components.

[0004] Patent Document 3 discloses an invention relating to a stretched film made of a polyethylene resin composition having specific physical properties, which is used as a base material for packaging materials having an excellent balance of rigidity, low shrinkage, and longitudinal tear strength.

[0005] Japanese Patent No. 6716764 Japanese Patent Application Laid-Open No. 2020-121455 International Publication No. 2022 / 153893

[0006] In order to impart barrier properties to packaging materials against water vapor and gases, a barrier layer may be formed on the surface of the packaging material by vapor deposition or coating. However, while the packaging material is stored in a rolled state, the barrier layer may become contaminated with low-molecular-weight components of polyethylene, which can result in a decrease in adhesive strength when the packaging material is subsequently dry-laminated with another substrate. Cited Documents 1 to 3 do not describe or suggest any means for solving this problem.

[0007] An object of the present invention is to provide a film that can be used as a substrate for packaging materials and has excellent low contamination properties.

[0008]

[0013] In view of the above problems, the present inventors have conducted extensive research and found that the above problems can be solved by using a film containing an ethylene polymer having specific physical properties, thereby completing the present invention.

[0014] Examples of embodiments of the present invention are shown below.

[0009] [1] A film containing an ethylene polymer satisfying the following requirements (a1) to (a4): (a1) a density of 940 to 980 kg / m 3 (a2) the melt flow rate (MFR) measured at 190°C under a load of 2.16 kg is 0.01 to 10 g / 10 min; (a3) ​​the content of low molecular weight components is 300 ppm or less; (a4) the ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (molecular weight distribution: Mw / Mn) measured by gel permeation chromatography (GPC) is 10 or less.

[0010] [2] The film according to item [1], wherein the thickness of the film is 0.005 mm or more and 1 mm or less. [3] The film according to item [2], wherein the film is a stretched film.

[0011] [4] A laminate comprising the film according to any one of items [1] to [3]. [5] The laminate according to item [4], further comprising a barrier layer.

[0012] [6] A package comprising the film according to any one of items [1] to [3]. [7] A package comprising the laminate according to item [4] or [5]. [8] A method for producing the film according to any one of items [1] to [3], the method comprising the step of melting a raw material resin containing the ethylene polymer.

[0013] The film of the present invention has excellent low contamination properties and can be suitably used as a recyclable packaging material, and further has excellent elastic modulus (rigidity) and transparency.

[0014] The present invention will be described in detail below. The film according to the present invention contains an ethylene polymer that satisfies the following requirements (a1) to (a4): (a1) a density of 940 to 980 kg / m 3(a2) The melt flow rate (MFR) measured at 190°C under a load of 2.16 kg is 0.01 to 10 g / 10 min. (a3) ​​The content of low molecular weight components is 300 ppm or less. (a4) The ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (molecular weight distribution: Mw / Mn) measured by gel permeation chromatography (GPC) is 10 or less.

[0015] [Ethylene-based polymer] <Requirement (a1)> The lower limit of the density of the ethylene-based polymer is usually 940 kg / m 3 or more, preferably 942 kg / m 3 More preferably, 944 kg / m 3 More preferably, 946 kg / m 3 or more, and even more preferably 948 kg / m 3 More preferably, 950 kg / m 3 The upper limit is usually 980 kg / m 3 Preferably 975 kg / m or less 3 or less, more preferably 970 kg / m 3 More preferably, 965 kg / m or less 3 The density of the ethylene polymer is within the above range, whereby rigidity and strength can be obtained. The density is a value measured in accordance with JIS K7112 (density gradient tube method).

[0016] <Requirement (a2)> The lower limit of the MFR of the ethylene polymer is usually 0.01 g / 10 min or more, preferably 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more, even more preferably 0.3 g / 10 min or more, still more preferably 0.5 g / 10 min or more, and particularly preferably 0.7 g / 10 min or more, and the upper limit is usually 10 g / 10 min or less, preferably 8 g / 10 min or less, more preferably 5 g / 10 min or less. When the MFR of the ethylene polymer is within the above range, strength and extrudability can be obtained.

[0017] <Requirement (a3)> The upper limit of the low-molecular-weight component content of the ethylene polymer is usually 300 ppm or less, preferably 250 ppm or less, more preferably 200 ppm or less, even more preferably 150 ppm or less, and particularly preferably 100 ppm or less, and the lower limit is not particularly limited, but is preferably 1 ppm or more, more preferably 5 ppm or more. When the low-molecular-weight component content of the ethylene polymer is within the above range, a film with excellent low-fouling properties can be obtained.

[0018] Here, the content of low molecular weight components in the present invention is determined by subjecting a suitable volume of Soxhlet extract (hexane) to a test solution, subjecting the test solution to GC (FID), and quantifying (n-C 20 H 42 converted), C 10 ~C 50 The values ​​are the amounts of the components. Details of Soxhlet extraction and the creation of calibration curves are shown below.

[0019] (1) Soxhlet extraction: Soxhlet extraction is carried out using 5 g of sample with a solvent, and the resulting solution is adjusted to 25 mL to 100 mL to be used as the test solution. 20 H 42 Creating a calibration curve by conversion C 10 ~C 50 Oligomer C 20 Quantitative determination by conversion is n-C 20 H 42 Using C as the standard, four standard solutions with different concentrations are subjected to GC (FID), and a calibration curve is prepared by the absolute calibration curve method using the obtained area values ​​and concentrations, and the slope and intercept of the calibration curve are determined. 10 ~C 50 Confirmation of the detection position of oligomer (n-paraffin) For the oligomer (n-paraffin) to be quantified, the detection position is confirmed by the retention time in the GC (FID) chromatogram when quantifying the oligomer using a paraffin mixed standard solution. (4) C 10 ~C 50 Oligomer (n-paraffin) C 20 Conversion quantification: C obtained by measuring the Soxhlet extract with GC (FID) 10 ~C 50The concentration (μg / mL) in the extract was calculated using Equation 1) from the peak area of ​​each of the (n-paraffins) and the slope and intercept obtained from the calibration curve, and then the C in the sample was calculated using Equation 2). 10 ~C 50 Calculate the quantitative value (w / w%) of (n-paraffin). Formula 1) Concentration in extract (μg / mL) = (area value - intercept) / slope Formula 2) Quantitative value (w / w%) = Concentration in extract (μg / mL) × fixed volume (mL) / sample weight (g) / 10,000

[0020] <Requirement (a4)> The upper limit of Mw / Mn of the ethylene polymer is usually 10 or less, preferably 8 or less, more preferably 7 or less, even more preferably 6 or less, still more preferably 5 or less, and particularly preferably 4.5 or less, and the lower limit is not particularly limited, but is preferably 1.0 or more, more preferably 1.5 or more, even more preferably 2.0 or more, still more preferably 2.2 or more, and particularly preferably 2.4 or more. When the Mw / Mn of the ethylene polymer is within the above range, the ethylene polymer contains few low-molecular-weight components, the ethylene polymer film is less sticky and has good stain resistance, and the ethylene polymer has good extrudability and can provide a film that is good in mechanical properties, such as dart impact strength.

[0021] The ethylene polymer is not particularly limited as long as it satisfies the above requirements (a1) to (a4), but is preferably an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 or more carbon atoms (ethylene-α-olefin copolymer). Specific examples of the α-olefin in the ethylene-α-olefin copolymer include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene.

[0022] The ethylene-based polymer contains 50 mol % or more and 100 mol % or less, preferably more than 50 mol % and 100 mol % or less, more preferably 55 to 100 mol %, and even more preferably 60 to 100 mol % of structural units derived from ethylene.

[0023] The ethylene polymer may contain structural units derived from one or more biomass-derived monomers (ethylene, α-olefin). The monomers constituting the polymer may be only biomass-derived monomers, or may be both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer derived from any renewable natural raw material or residue thereof, such as a plant-derived or animal-derived material, including fungi, yeast, algae, and bacteria, and contains, as carbon, 14 C isotope 1×10 -12 The biomass carbon concentration (pMC) measured in accordance with ASTM D6866 is about 100 (pMC). The biomass-derived monomer (ethylene) can be obtained, for example, by a conventionally known method.

[0024] It is preferable that the ethylene polymer contains a structural unit derived from a biomass-derived monomer from the viewpoint of reducing the environmental load (mainly greenhouse gas reduction). 14 C isotope 10 -12 ~10 -14 Other than the proportion of ethylene in the polymer, its molecular structure is the same as that of ethylene polymers made from fossil fuel-derived monomers, and therefore its performance is said to be unchanged.

[0025] The ethylene polymer may contain a chemically recycled monomer (ethylene, α-olefin). The monomers constituting the polymer may be only the chemically recycled monomer, or may contain the chemically recycled monomer and a fossil fuel-derived monomer and / or a biomass-derived monomer. The chemically recycled monomer can be obtained by a conventionally known method.

[0026] It is preferable that the ethylene polymer contains a chemically recycled monomer from the viewpoint of reducing the environmental load (mainly reducing waste). Even if the raw material monomer contains a chemically recycled monomer, the chemically recycled monomer is a monomer obtained by depolymerizing or thermally decomposing a polymer such as waste plastics to return it to a monomer unit such as ethylene, or a monomer produced using such a monomer as a raw material. Therefore, if the polymer production conditions, such as the polymerization catalyst, polymerization process, and polymerization temperature, are equivalent, the molecular structure is equivalent to that of an ethylene polymer made from a fossil fuel-derived monomer. Therefore, the performance of these polymers is also considered to be unchanged.

[0027] The ethylene polymer can be produced by a high-temperature solution process using a known catalyst such as a Ziegler-Natta catalyst or a metallocene catalyst. While the catalyst is not particularly limited, a Ziegler-Natta catalyst is preferred in consideration of the balance with extrudability, since it produces an ethylene polymer with a moderate molecular weight distribution. The high-temperature solution process is a method in which a polymer is produced in a homogeneous state at high temperatures under pressure using a solvent such as hexane. In the high-temperature solution process, the reaction proceeds in a homogeneous phase, resulting in a narrow compositional distribution of the resulting ethylene polymer, thereby suppressing the formation of oligomers and other volatile compounds. Furthermore, the solvent such as hexane is removed by flashing under atmospheric pressure, and the precipitated polymer is dried separately. Even during flashing, oligomers and volatile compounds are removed along with the solvent. When producing the ethylene polymer industrially by the high-temperature solution process, it is preferable to employ a continuous process in which the solvent and raw materials are continuously supplied and the above-mentioned flashing operation is repeatedly performed to recover the product and raw material monomers. Therefore, the film of the ethylene polymer (A) obtained by the high-temperature solution method is characterized in that the amount of components that ooze out from the film is extremely small, and also has excellent dart impact strength.

[0028] [Film] The film of the present invention is characterized by containing the above-mentioned ethylene polymer. Furthermore, the film of the present invention may contain, as necessary, at least one of various additives added to general polyolefin films, such as a weather stabilizer, a heat stabilizer, an antistatic agent, an antifogging agent, an antiblocking agent, a slip agent, a lubricant, a pigment, a dripping agent, and a nucleating agent, as long as the object of the present invention is not impaired.

[0029] The film of the present invention can be produced by molding the raw material resin containing the above-mentioned ethylene-based polymer by a known method including a step of melting. The film of the present invention is a non-stretched film or a stretched film. In consideration of mechanical strength, etc., a stretched film is preferred.

[0030] The thickness of the film of the present invention may be appropriately set depending on various applications, but in general, the lower limit is preferably 0.005 mm (5 μm) or more, more preferably 0.01 mm (10 μm) or more, and the upper limit is preferably 1 mm or less, more preferably 0.5 mm or less, and even more preferably 0.3 mm or less. By keeping the film thickness within the above range, a balance between rigidity and strength as a packaging material can be achieved.

[0031] <Stretched Film> When the film of the present invention is a stretched film, it is a uniaxially stretched film or a biaxially stretched film.

[0032] The stretched film may be a single-layer film or a multilayer film. When a multilayer film is formed, the ethylene polymer may be used in any layer or in multiple layers. The layer structure of the multilayer film is not particularly limited, and examples thereof include the structures shown below. the ethylene-based polymer / linear low-density polyethylene or medium-density polyethylene / the ethylene-based polymer, the ethylene-based polymer / linear low-density polyethylene or medium-density polyethylene / medium-density polyethylene, the ethylene-based polymer / high-density polyethylene / linear low-density polyethylene or medium-density polyethylene / high-density polyethylene / the ethylene-based polymer, the ethylene-based polymer / high-density polyethylene / linear low-density polyethylene or medium-density polyethylene / high-density polyethylene / linear low-density polyethylene or medium-density polyethylene, the ethylene-based polymer / linear low-density polyethylene or medium-density polyethylene / linear low-density polyethylene or medium-density polyethylene / linear low-density polyethylene or medium-density polyethylene, high-density polyethylene / linear low-density polyethylene or medium-density polyethylene / the ethylene-based polymer ... The above-mentioned ethylene-based polymer / medium-density polyethylene / linear low-density polyethylene / medium-density polyethylene / the above-mentioned ethylene-based polymer; The above-mentioned ethylene-based polymer / linear low-density polyethylene or medium-density polyethylene / linear low-density polyethylene / linear low-density polyethylene or medium-density polyethylene / linear low-density polyethylene or medium-density polyethylene.

[0033] The stretching ratio of the stretched film is preferably 1.5 times or more, more preferably 2.0 times or more, particularly preferably 2.5 times or more, and most preferably 3.0 times or more. There is no particular upper limit to the stretching ratio, but it is preferably 60 times or less, more preferably 50 times or less. By having the stretching ratio within the above range, rigidity and strength can be obtained.

[0034] The method for producing the stretched film is not particularly limited, but examples thereof include a method in which a film (raw film to be stretched) obtained by a known melt extrusion molding method is stretched.

[0035] Examples of methods for stretching the raw sheet include a method of simultaneous or sequential biaxial stretching in the longitudinal and transverse directions using a tenter method, a method of simultaneous biaxial stretching in the longitudinal and transverse directions using a tubular method, and a method of uniaxial stretching in the flow direction of the film by using a difference in the rotation speed ratio of two or more rolls.

[0036] In the uniaxial stretching, it is preferable to unwind the film into a roll stretching machine, preheat it with a preheating roll, and then uniaxially stretch it in the MD direction (take-up speed direction). From the viewpoint of improving production efficiency, it is preferable to preheat the raw film to be stretched and then immediately uniaxially stretch it in the MD direction. In the present invention, uniaxial stretching means stretching in a uniaxial direction, but it may be stretched in a direction different from the uniaxial direction to the extent that the effect of the present invention is not impaired. This is because, depending on the stretching equipment used, even if uniaxial stretching is attempted, it may actually be stretched in a direction different from the uniaxial direction.

[0037] The stretched film may be annealed, if necessary, by bringing the stretched sheet into contact with a heated roll.

[0038] The stretched film has high transparency, and the haze measured under the conditions employed in the examples described below is preferably 20% or less, more preferably 15% or less.

[0039] [Laminate] The laminate of the present invention is characterized by including the above-mentioned film of the present invention. The laminate of the present invention may have a plurality of layers made of the film of the present invention. The above-mentioned film of the present invention is preferably used as a substrate in the laminate. Other layers in the laminate of the present invention can be appropriately adopted depending on the application, and examples thereof include a barrier layer.

[0040] The laminate of the present invention can be produced by known methods, such as coextrusion molding of one or more thermoplastic resins, extrusion lamination, dry lamination, and thermal lamination.

[0041] In addition, in an embodiment in which the laminate of the present invention includes a barrier layer, the barrier layer can be formed on the surface of the film of the present invention by known metal vapor deposition, coating, or co-extrusion methods.

[0042] The film of the present invention can be further provided with various functions by laminating it. Examples of lamination methods include co-extrusion with a barrier resin (e.g., EVOH, Ny, etc.) or an adhesive resin (e.g., Admer, etc.), and coating the surface (e.g., vapor deposition film, etc.). The vapor deposition film may be made of a metal or an inorganic oxide.

[0043] Examples of metals constituting the metal vapor deposition film include aluminum, chromium, tin, nickel, copper, silver, gold, platinum, etc. Examples of metal oxides include aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide.

[0044] [Package] The package of the present invention is characterized by including the film of the present invention described above. For example, it can be obtained by forming the laminate of the present invention described above into a bag-like container, filling it with an article to be packaged (contents) for various uses, and heat-sealing it.

[0045] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the following examples, MFR, density, molecular weight distribution (Mw / Mn), amount of low molecular weight components, elastic modulus, haze, and low staining properties were measured or evaluated as follows.

[0046] <Melt flow rate (MFR) [g / 10 min]> The MFR of the ethylene polymers used in the examples and comparative examples was measured in accordance with JIS K7210 under conditions of 190°C and a load of 2.16 kg (kgf).

[0047] <Density [kg / m 3 The density of the ethylene polymers used in the examples and comparative examples was measured by a density gradient tube method in accordance with JIS K7112 using strands obtained during melt index measurement.

[0048] <Molecular Weight Distribution (Mw / Mn)> The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the ethylene polymers used in the Examples and Comparative Examples were values ​​measured by gel permeation chromatography (GPC), and were calculated based on a conversion method using a calibration curve prepared using commercially available monodisperse polystyrene.

[0049] <Amount of Low-Molecular-Weight Components> The amount of low-molecular-weight components in the ethylene polymers used in the Examples and Comparative Examples was determined as follows. An appropriate volume of Soxhlet extract (hexane) was used as a test solution, and the test solution was subjected to GC (FID) and quantified (n-C 20 H 42 converted), C 10 ~C 50 The amount of the component was taken as the amount of the low molecular weight component. Details are as described above.

[0050] <Elastic Modulus> Test specimens were punched out from the films obtained in the Examples or Comparative Examples to a dumbbell shape conforming to JIS K6781. The direction punched parallel to the film take-up direction was defined as the MD (machine direction). The test specimens were set in the air chucks of a universal testing machine, and a tensile test was carried out at a chuck distance of 80 mm and a tensile speed of 200 mm / min. The slope of the initial stress versus displacement was defined as the elastic modulus.

[0051] <Haze> The haze of the films obtained in the examples and comparative examples was measured according to the method specified in JIS K 7136.

[0052] <Dart Impact Strength> Dart impact strength was measured according to ASTM D1709 under the following conditions. The test specimen was clamped using an air clamp, and a hemispherical dart was dropped from a certain height. The load at which the test specimen broke 50% was read from the graph. The number of drops per level was 10. The dart impact strength was evaluated using a monolayer film (unstretched film) with a thickness of 40 μm and a width of 320 mm, which was produced under the following molding conditions.

[0053] <<Molding Conditions>> Molding was performed using a 50 mmφ inflation molding machine manufactured by Modern Machinery, a barrier type screw, a 100 mmφ (diameter) die, a two-gap type air ring, an extrusion rate of 28.8 kg / hr, and a take-up speed of 20 m / min.

[0054] The ethylene polymers used in the Examples and Comparative Examples were melt-kneaded at 190°C in an extruder, and then formed into unstretched films (raw films) having a thickness of 40 µm in an inflation molding machine. The resin pressure [MPa] at this time was divided by the extrusion rate [kg / h] to evaluate the extrudability.

[0055] <Low Contamination> The ethylene polymer used in the Examples or Comparative Examples was melt-kneaded at 190°C in an extruder, and then an unstretched film (raw film) having a thickness of 40 µm was formed using an inflation molding machine. The aluminum-deposited PET film and the film of the present invention were overlapped so that the vapor-deposited surface thereof was in close contact with each other, and the film was subjected to a pressure of 10 kgf / 100 cm in the lamination direction. 2A load of 1000 kJ / cm was applied, and the wetting index (unit: dyn / cm) of the vapor-deposited surface was measured before application of the load (initial value) and after application of the load at 23°C for 1 day. Vapor-deposited surface wetting index retention rate [%] = after application of a load at 23°C for 1 day / before application of the load (initial value) x 100, and the evaluation was based on the following criteria: Good: Vapor-deposited surface wetting index retention rate ≧ 60% Bad: Vapor-deposited surface wetting index retention rate < 60%

[0056] [Example 1] An ethylene-based polymer was produced by a solution process using a Ziegler catalyst, had an MFR of 1.0 g / 10 min and a density of 957 kg / m 3 The raw film was melt-kneaded at 230°C in an extruder using Prime Polymer's "Neozex 5510F" and then cast into a 125 μm thick unstretched film (raw film) using a cast molding machine. This raw film was uniaxially stretched at a stretch ratio of 5x while heated to 120°C using a heated roll to obtain a 25 μm thick uniaxially stretched film. The haze and modulus of the resulting unstretched film, as well as the haze of the stretched film, were evaluated. The dirt impact strength, extrudability, and low contamination were also evaluated as described above. The results are shown in Table 1.

[0057] [Example 2] An ethylene polymer was produced by a solution process using a Ziegler catalyst, and had an MFR of 2.2 g / 10 min and a density of 955 kg / m 3 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5520F" manufactured by Prime Polymer Co., Ltd. was used. Measurements and evaluations were also carried out in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.

[0058] [Example 3] An ethylene-based polymer was produced by a slurry method using a metallocene catalyst, and had an MFR of 1.1 g / 10 min and a density of 957 kg / m 3 Measurements and evaluations were carried out in the same manner as in Example 1, except that "EVL-H SP6011" manufactured by Prime Polymer Co., Ltd., which has a viscosity of 1000 MPa (1000 psi), was used (some measurements and evaluations were omitted). The results are shown in Table 1.

[0059] [Example 4] An ethylene polymer was produced by a solution process using a Ziegler catalyst, and had an MFR of 2.3 g / 10 min and a density of 953 kg / m 3 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5521F" manufactured by Prime Polymer Co., Ltd. was used. Measurements and evaluations were also performed in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.

[0060] [Example 5] An ethylene-based polymer was produced by a solution method using a Ziegler catalyst, and had an MFR of 2.3 g / 10 min and a density of 948 kg / m 3 An unstretched film was obtained in the same manner as in Example 1, except that "Neozex 5021F" manufactured by Prime Polymer Co., Ltd. was used. Measurements and evaluations were also carried out in the same manner as in Example 1 (note that some measurements and evaluations were omitted). The results are shown in Table 1.

[0061] [Comparative Example 1] An ethylene-based polymer having an MFR of 1.0 g / 10 min and a density of 958 kg / m 3 An unstretched film and a stretched film were obtained in the same manner as in Example 1, except that "HI-ZEX 3600F" manufactured by Prime Polymer Co., Ltd., which is a polymer having a viscosity of 100 MPa (100 MPa), was used. Measurements and evaluations were also carried out in the same manner as in Example 1. The results are shown in Table 1.

[0062] [Comparative Example 2] An ethylene polymer having an MFR of 0.04 g / 10 min and a density of 951 kg / m 3 An unstretched film and a stretched film were obtained in the same manner as in Example 1, except that "Hi-Zex 7000F" manufactured by Prime Polymer Co., Ltd., which has a viscosity of 100 MPa (100 psi), was used. Measurements and evaluations were also carried out in the same manner as in Example 1. The results are shown in Table 1.

[0063] [Comparative Example 3] An ethylene-based polymer having an MFR of 4 g / 10 min and a density of 938 kg / m 3 An unstretched film was obtained in the same manner as in Example 1, except that "Evolue SP4030" manufactured by Prime Polymer Co., Ltd., which has a viscosity of 1000 MPa (1000 psi), was used. Measurements and evaluations were also carried out in the same manner as in the examples (note that some measurements and evaluations were omitted). The results are shown in Table 1.

[0064]

Claims

DEPCT691. Films assembled with ethylene-based polymers that meet the following specifications (a1) to (a4): (a1) density is 940 to 980 kg / m³; (a2) melt flow rate (MFR) measured at 190 °C and a load of 2.16 kg is 0.01 to 10 g / 10 min; (a3) ​​amount of low molecular weight component is 300 parts per million or less; and (a4) ratio of average molecular weight by weight (Mw) to average molecular weight by number (Mn) (molecular weight distribution; Mw / Mn) is measured. Measured by gel selective chromatography (GPC) is 10 or less.

2. Film under claim 1 where the film thickness is 0.005 mm or more and 1 mm or less.

3. Film under claim 2 where the film is stretch film.

4. Laminate composed of any one of the films under claims 1 to 3.

5. Laminate under claim 4 incorporated with an additional barrier layer.

6. Packaging composed of any one of the films under claims 1 to 3.

7. Packaging composed of a laminate under claim 4. 8.The method for the production of films under any of the claims 1 through 3 is a method that includes a step of melting the resin, a raw material consisting of an ethylene-based polymer;