Film, laminate and packaging container

Abstract

An object of the present disclosure is to improve the heat distortion resistance of a film containing polyethylene as a main component.SOLUTION: A film containing, as a main component, a high-density polyethylene (A) satisfying at least one requirement selected from the group consisting of the following (1) and (2): (1) The high density polyethylene (A) has a peak having a Full-WidthatQuarter-Maximum value of less than 1.5 in a differential molecular weight distribution curve obtained by high temperature gel permeation chromatography (GPC) measurement, and (2) a differential (LogM90 / LogM10) between a 90 percentile value (LogM90) and a 10 percentile value (LogM10) in the differential molecular weight distribution curve of the high density polyethylene (A) is less than 1.25.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to films, laminates and packaging containers. [Background technology]

[0002] Packaging containers are used to store contents such as liquids and powders. Packaging containers are made using, for example, packaging materials that include a base material and a heat-sealing layer (see, for example, Patent Document 1). Polyethylene film is flexible, transparent, and has excellent heat-sealing properties, so it is widely used as the heat-sealing layer that constitutes the packaging material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-55156 Summary of the Invention [Problem to be solved by the invention]

[0004] Compared with other thermoplastic resins, polyethylene is a resin that softens at a relatively low temperature. Therefore, when a polyethylene film is used as the substrate of a packaging material, the substrate may deform or, in some cases, melt when the packaging material is heat-sealed. Furthermore, polyethylene film may have insufficient strength compared to other thermoplastic resin films. For this reason, resin films with excellent heat resistance and strength, such as polyester film and nylon film, are generally used as the substrate. For example, a packaging material comprising a polyester film or nylon film as the substrate and a polyethylene film as the heat-sealing layer is used.

[0005] In recent years, with the growing demand for a recycling-oriented society, attempts have been made to recycle packaging materials. However, packaging materials that contain different types of resin films, such as a combination of polyester film or nylon film and polyethylene film, are difficult to separate by type of resin. Therefore, such packaging materials tend not to be suitable for recycling.

[0006] Stretched films and the like that have improved heat resistance and strength by stretching polyethylene films have been studied. However, the heat resistance of these films is still insufficient, and they tend to undergo significant thermal deformation, for example, when placed in a high-temperature environment. An object of the present disclosure is to improve the thermal deformation resistance of films that contain polyethylene as a main component. [Means for solving the problem]

[0007] A film according to one embodiment of the present disclosure contains, as a main component, a high-density polyethylene (A) that satisfies at least one requirement selected from the group consisting of the following (1) and (2): (1) The high-density polyethylene (A) has a peak with a full-width at quarter-maximum (FWQM) value of less than 1.5 in a differential molecular weight distribution curve (horizontal axis: common logarithm (LogM) of molecular weight (M); vertical axis: value dW / d(LogM) obtained by differentiating cumulative concentration fraction (W) with common logarithm of molecular weight (M)) obtained by high-temperature gel permeation chromatography (GPC) measurement; (2) The 90th percentile value (LogM) of the molecular weight distribution in the differential molecular weight distribution curve of high-density polyethylene (A) 90 ) and the 10th percentile (LogM 10 ) and the difference (LogM 90 -LogM 10 ) is less than 1.25.

[0008] The stretched film according to one embodiment of the present disclosure is obtained by stretching the above-mentioned film. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a film that contains polyethylene as a main component, has excellent heat resistance, and exhibits little thermal deformation when placed in a high-temperature environment, for example. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic cross-sectional view showing one embodiment of a stretched film. [Figure 2] FIG. 2 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 3] FIG. 3 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 4] FIG. 4 is a schematic cross-sectional view showing one embodiment of the laminate. [Figure 5] FIG. 5 is a schematic diagram illustrating a differential molecular weight distribution curve. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described in detail. For clarity of explanation, the drawings may show the width, thickness, shape, etc. of each layer more schematically than in the embodiments, but these are merely examples and do not limit the interpretation of the embodiments of the present disclosure. In this specification and each drawing, elements similar to those already described with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0012] In this specification, when multiple upper limit candidates and multiple lower limit candidates are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit candidate with any one lower limit candidate. Examples of such parameters include physical properties, component content, and layer thickness. As an example, the following statement will be explained: "Parameter B is preferably A1 or greater, more preferably A2 or greater, and even more preferably A3 or greater. Parameter B is preferably A4 or less, more preferably A5 or less, and even more preferably A6 or less." In this example, the numerical range of parameter B may be A1 or greater and A4 or less, A1 or greater and A5 or less, A1 or greater and A6 or less, A2 or greater and A4 or less, A2 or greater and A5 or less, A2 or greater and A6 or less, A3 or greater and A4 or less, A3 or greater and A5 or less, or A3 or greater and A6 or less.

[0013] In this specification, polyethylene refers to a polymer in which the content of ethylene-derived structural units exceeds 50 mol% of the total amount of structural units derived from polymerizable monomers. In this polymer, the content of ethylene-derived structural units is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. The content is measured by nuclear magnetic resonance spectroscopy (NMR method).

[0014] In this specification, the polyethylene may be a homopolymer of ethylene or a copolymer of ethylene and an ethylenically unsaturated monomer other than ethylene. Examples of the ethylenically unsaturated monomer other than ethylene include α-olefins having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene; vinyl monomers, such as vinyl acetate and vinyl propionate; and (meth)acrylic acid esters, such as methyl (meth)acrylate and ethyl (meth)acrylate.

[0015] In this specification, examples of polyethylene include high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, high-pressure low-density polyethylene, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. From the viewpoint of reducing the environmental load, the polyethylene may be biomass-derived polyethylene (hereinafter also referred to as "biomass polyethylene") or mechanically or chemically recycled polyethylene (hereinafter also referred to as "recycled polyethylene").

[0016] In this specification, the density of polyethylene is as follows: The density of the high density polyethylene is preferably 0.945 g / cm 3 The density of the high density polyethylene is preferably greater than 0.970 g / cm 3 The density of the medium density polyethylene is preferably 0.930 g / cm or less. 3 More than 0.945g / cm 3 The density of the linear low density polyethylene is preferably 0.860 g / cm 3 More than 0.930g / cm 3 less than 0.900 g / cm 3 More than 0.930g / cm 3 The density of the high-pressure low-density polyethylene is preferably less than 0.860 g / cm 3 More than 0.930g / cm 3 less than 0.900 g / cm 3 More than 0.930g / cm 3 In this specification, the density of polyethylene is measured in accordance with JIS K7112-2:2023 (density gradient tube method, 23°C).

[0017] In this specification, high-density polyethylene (HDPE) includes, for example, ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having from 3 to 20 carbon atoms, with α-olefins having from 3 to 8 carbon atoms being preferred, and α-olefins having from 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymers (C4-HDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymers (C6-HDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymers (C8-HDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomer is not limited to the above-mentioned comonomers, and additional comonomers may also be used.

[0018] In this specification, examples of medium-density polyethylene (MDPE) include ethylene homopolymers and ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having from 3 to 20 carbon atoms, with α-olefins having from 3 to 8 carbon atoms being preferred, and α-olefins having from 4 to 8 carbon atoms being more preferred. Examples of ethylene-α-olefin copolymers include ethylene-1-butene copolymers (C4-MDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymers (C6-MDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymers (C8-MDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomers are not limited to the above-mentioned comonomers, and additional comonomers may also be used.

[0019] Linear low-density polyethylene is polyethylene obtained by polymerizing ethylene and a small amount of α-olefins using a polymerization method with a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst. High-pressure low-density polyethylene is polyethylene obtained by polymerizing ethylene using a high-pressure polymerization method.

[0020] In this specification, examples of linear low-density polyethylene (LLDPE) include ethylene-α-olefin copolymers. Examples of α-olefins include the above-mentioned α-olefins having from 3 to 20 carbon atoms, with α-olefins having from 3 to 8 carbon atoms being preferred, and α-olefins having from 4 to 8 carbon atoms being more preferred. Examples of linear low-density polyethylene include ethylene-1-butene copolymers (C4-LLDPE) in which the comonomer is at least 1-butene, ethylene-1-hexene copolymers (C6-LLDPE) in which the comonomer is at least 1-hexene, and ethylene-1-octene copolymers (C8-LLDPE) in which the comonomer is at least 1-octene. In these copolymers, the comonomers are not limited to the above-mentioned comonomers, and additional comonomers may also be used.

[0021] Polyethylenes with different molecular weight distributions, molecular weights, densities, or branches, which will be described later, can be obtained by appropriately selecting the polymerization method and polymerization conditions, etc. For example, it is preferable to use a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst as the polymerization catalyst and carry out polymerization in one stage or in two or more stages by any of gas phase polymerization, slurry polymerization, solution polymerization, and high-pressure ionic polymerization.

[0022] From the viewpoint of film-forming and processability, the melt flow rate (MFR) of the polyethylene herein is preferably 0.01 g / 10 min or more or 0.05 g / 10 min or more, more preferably 0.1 g / 10 min or more, even more preferably 0.2 g / 10 min or more, even more preferably 0.3 g / 10 min or more, particularly preferably 0.5 g / 10 min or more, and preferably 30 g / 10 min or less, more preferably 20 g / 10 min or less, even more preferably 10 g / 10 min or less, even more preferably 5 g / 10 min or less, particularly preferably 3 g / 10 min or less, for example, 0.01 g / 10 min or more and 30 g / 10 min or less. The MFR of polyethylene herein is measured by Method A in accordance with JIS K7210-1:2014 at a temperature of 190°C under a load of 2.16 kg.

[0023] In this specification, the melting point of the high-density polyethylene and the medium-density polyethylene is, from the viewpoints of strength, heat resistance, and the like, preferably 110°C or higher, more preferably 115°C or higher, even more preferably 120°C or higher, and particularly preferably 125°C or higher, and is preferably 140°C or lower, and may be, for example, 135°C or lower, for example, 110°C or higher and 140°C or lower. In this specification, the melting point of the linear low-density polyethylene and the high-pressure low-density polyethylene is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 85°C or higher, and is preferably lower than 130°C, for example, lower than 125°C or lower than 120°C, for example, 70°C or higher but lower than 130°C. In this specification, the melting points of various materials are melting peak temperatures obtained by differential scanning calorimetry (DSC) in accordance with JIS K7121:2012 (3.(2) (however, using test specimens conditioned at a cooling rate of 10°C / min)).

[0024] In this specification, each of the components (for example, polyolefins such as polyethylene, α-olefins, and additives) appearing in the following description may be used alone or in combination of two or more.

[0025] In this specification, "film" and "sheet" may be referred to, but "film" and "sheet" are not distinguished from each other solely on the basis of the difference in name.

[0026] In this specification, a stretched film that has a small dimensional change rate in the stretching direction when placed in a high-temperature environment (preferably small thermal shrinkage) is also referred to as "excellent thermal shape stability."

[0027] In this specification, the term "main component" in a layer refers to a component that accounts for 50% by mass or more in the layer, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0028] [Films and oriented films] The film of the present disclosure contains high-density polyethylene (A) as a main component. The stretched film of the present disclosure is obtained by stretching a film containing high-density polyethylene (A) as a main component. In the following description, unless otherwise specified, "the film" refers to the film before the stretching treatment. The stretched film 1 shown in FIG. 1 is a single-layer film. The high-density polyethylene (A) will be described below.

[0029] High-density polyethylene (A) is a high-density polyethylene having a narrow molecular weight distribution in the differential molecular weight distribution curve obtained by high-temperature gel permeation chromatography (GPC) measurement. In the differential molecular weight distribution curve obtained by high-temperature GPC measurement (horizontal axis: common logarithm (LogM) of molecular weight (M), vertical axis: value dW / d(LogM) obtained by differentiating cumulative concentration fraction (W) by common logarithm of molecular weight (M)), the high-density polyethylene (A) is a polyethylene having a peak with a Full-Width at Quarter-Maximum (FWQM) value smaller than that of the target polyethylene, or a peak with a 90th percentile (LogM) of the molecular weight distribution, as described below. 90) and the 10th percentile (LogM 10 ) and the difference (LogM 90 -LogM 10 ) is smaller than that of the target polyethylene, it can be said that the polyethylene has a sharper molecular weight distribution (narrower molecular weight distribution) than the target polyethylene.

[0030] W is the cumulative concentration fraction (cumulative mass fraction) of the molecular weight of the polymer being measured, such as high-density polyethylene. Log is the common logarithm. M is the molecular weight of the polymer being measured, such as high-density polyethylene. The FWQM value refers to the width of the peak (LogM2-LogM1) when the value of dW / d(LogM) is 1 / 4 of the peak height (peak top height) appearing on the differential molecular weight distribution curve (see Figure 5A). Hereinafter, FWQM will also be referred to as the "1 / 4 width." Polydispersity (Mw / Mn) is sometimes used as an index of the spread of the differential molecular weight distribution. Here, Mn is the number-average molecular weight, and Mw is the weight-average molecular weight. The quarter width can evaluate the shape of the tail of the differential molecular weight distribution more appropriately than the polydispersity. This is because the quarter width evaluates the shape of the distribution at a position away from the peak top along the horizontal axis, rather than the shape near the peak top of the differential molecular weight distribution. Therefore, the quarter width can evaluate the shape of the differential molecular weight distribution (thickness of the tail of the distribution, sharpness or broadness) more appropriately than the polydispersity. A small quarter width indicates that the differential molecular weight distribution has thin, sharp tails on both sides and a small spread of the differential molecular weight distribution. Conversely, a large quarter width indicates that the differential molecular weight distribution has thick, broad tails on both sides and a large spread of the differential molecular weight distribution.

[0031] When two or more overlapping peaks exist in a differential molecular weight distribution curve, the 1 / 4 width is calculated as follows: The peak with the smallest molecular weight at its peak top position is designated P1, and the height of P1 (maximum value of dW / d(LogM)) is designated H1. The peak with the largest molecular weight at its peak top position is designated P2, and the height of P2 (maximum value of dW / d(LogM)) is designated H2. The molecular weight value satisfying dW / d(LogM) = H1 / 4 on the differential molecular weight distribution curve on the lower molecular weight side than the peak top position of P1 is designated M1. The molecular weight value satisfying dW / d(LogM) = H2 / 4 on the differential molecular weight distribution curve on the higher molecular weight side than the peak top position of P2 is designated M2. The difference between Log(M2) and Log(M1) (Log(M2) - Log(M1)) is the above-mentioned "1 / 4 width" (see Figure 5B). However, peaks whose height from the baseline (in the case of shoulder peaks, the height of the shoulder from the baseline) is 0.10 or less will be ignored.

[0032] The differential molecular weight distribution curve for a polymer can be obtained as follows: First, an integrated molecular weight distribution curve is obtained by high-temperature GPC measurement. The integrated molecular weight distribution curve is obtained by plotting data with the common logarithm (LogM) of the polymer molecular weight on the horizontal axis and the cumulative polymer concentration fraction on the vertical axis. The vertical axis of the integrated molecular weight distribution curve shows the mass fraction of polymers below a certain molecular weight in the entire polymer. Next, the differential value of the above curve (the slope of the integrated molecular weight distribution curve) for each molecular weight is determined. The horizontal axis represents the common logarithm (LogM) of the molecular weight (M) and the vertical axis represents the above differential value (the value obtained by differentiating the integrated concentration fraction by the common logarithm of the molecular weight, dW / d(LogM)). In this way, the differential molecular weight distribution curve is obtained. Details of the conditions for high-temperature GPC measurement are described in the Examples section.

[0033] The present inventors have found that the shape of the peak in the differential molecular weight distribution curve of high-density polyethylene is related to the heat resistance (specifically, heat distortion resistance) of the stretched film. For example, a peak having a quarter width of less than 1.5 and / or a peak having a 90th percentile value (LogM 90 ) and the 10th percentile (LogM 10 ) and the difference (LogM 90 -LogM 10 High-density polyethylene (A) having a molecular weight distribution (Mw) of less than 1.25 can be said to have a sharp molecular weight distribution (narrow molecular weight distribution). Stretched films containing high-density polyethylene (A) as a main component tend to be less susceptible to thermal deformation (e.g., thermal shrinkage) in the stretching direction despite being stretched. Therefore, the stretched film of the present disclosure can effectively suppress thermal deformation (e.g., thermal shrinkage) during heat sealing, for example.

[0034] Although the reason for this is unclear, the inventors speculate as follows: Polyethylene with a broad molecular weight distribution contains a large amount of polyethylene with a relatively low molecular weight. Therefore, when the film is heated, molecular motion begins with the low molecular weight polyethylene, making the film prone to thermal deformation (e.g., thermal shrinkage). On the other hand, polyethylene with a sharp molecular weight distribution contains spherulites of similar size, and these spherulites contain many lamellar crystals of similar size. These lamellar crystals are neatly aligned by stretching. The increase in oriented crystals by stretching suppresses molecular motion of the polyethylene. These oriented crystals contribute to suppressing thermal deformation, such as thermal shrinkage, of the film. Note that the above explanation is merely speculation and does not in any way limit the stretched film of the present disclosure.

[0035] Stretched films containing high-density polyethylene (A) as a primary component tend to be able to suppress the generation of white powder on the film surface. This is presumably because high-density polyethylene (A) has a narrow molecular weight distribution, and therefore contains a relatively small proportion of low-molecular-weight polyethylene. Stretched films containing high-density polyethylene (A) as a primary component also tend to have low external haze and excellent transparency.

[0036] The high-density polyethylene (A) preferably has a peak having a full-width at quarter-maximum (FWQM) value (quarter width) of less than 1.5 in a differential molecular weight distribution curve obtained by high-temperature GPC measurement. The quarter width of the peak of the high-density polyethylene (A) is, for example, less than 1.5, preferably 1.47 or less, more preferably 1.43 or less, particularly preferably 1.4 or less, and preferably 0.8 or more, more preferably 1.0 or more, even more preferably 1.1 or more, and particularly preferably 1.2 or more. The quarter width is, for example, 0.8 or more and less than 1.5.

[0037] The 90th percentile value (LogM) of the molecular weight distribution (hereinafter also referred to as "differential molecular weight distribution") in the differential molecular weight distribution curve obtained by high-temperature GPC measurement of high-density polyethylene (A) 90 ) and the 10th percentile (LogM 10 ) and the difference (LogM 90 -LogM 10 ) is preferably less than 1.25.

[0038] 10th percentile (LogM 10 ) means that the molecular weight is M 10 The molecular weight M when the content of the following polyethylene is 10% by mass relative to the total polyethylene 10 The 10th percentile value is determined as the common logarithm of the molecular weight when the integrated value of the concentration fraction in the integrated molecular weight distribution curve is 10% by mass.

[0039] 90th percentile (LogM90 ) means that the molecular weight is M 90 The molecular weight M when the content of the following polyethylene is 90% by mass of the total polyethylene 90 The 90th percentile value is determined as the common logarithm of the molecular weight when the integrated value of the concentration fraction in the integrated molecular weight distribution curve is 90% by mass.

[0040] LogM 90 and LogM 10 can be used as an index for evaluating the thickness of the tail of the differential molecular weight distribution. The difference can evaluate the shape of the tail of the differential molecular weight distribution more appropriately than the polydispersity. This is because the difference evaluates the shape of the distribution at a position away from the peak top in the horizontal axis direction, rather than the shape near the peak top of the differential molecular weight distribution. Therefore, the difference can evaluate the shape of the differential molecular weight distribution (thickness of the tail of the distribution, sharp or broad shape) more appropriately than the polydispersity. A small difference indicates that the differential molecular weight distribution has thin, sharp tails on both sides and a small spread of the differential molecular weight distribution. Conversely, a large difference indicates that the differential molecular weight distribution has thick, broad tails on both sides and a large spread of the differential molecular weight distribution.

[0041] The difference (LogM 90 -LogM 10 ) is preferably less than 1.25, more preferably 1.20 or less, even more preferably 1.15 or less, particularly preferably 1.12 or less, and is preferably 0.70 or more, more preferably 0.80 or more, even more preferably 0.90 or more, particularly preferably 1.00 or more. The difference is, for example, 0.70 or more and less than 1.25.

[0042] The maximum value of dW / d(LogM) at the peak of the high-density polyethylene (A) is, for example, 0.80 or more, preferably 0.85 or more, more preferably 0.90 or more, particularly preferably 0.95 or more, and preferably 1.30 or less, more preferably 1.25 or less, even more preferably 1.20 or less, particularly preferably 1.10 or less. The maximum value is, for example, 0.80 or more and 1.30 or less.

[0043] The film may contain two or more types of high-density polyethylene (A). In the case of a mixture of two or more types of high-density polyethylene (A), it is preferable that the differential molecular weight distribution curve of the mixture has a peak that satisfies the ¼ width requirement (and preferably also the maximum value of dW / d(LogM) requirement), and it is also preferable that the differential molecular weight distribution of the mixture satisfies the difference requirement.

[0044] The high-density polyethylene (A) may have a unimodal or multimodal, such as bimodal, differential molecular weight distribution curve, and preferably has a unimodal differential molecular weight distribution curve having one peak with a quarter width of less than 1.5.

[0045] The weight average molecular weight (Mw) of the high density polyethylene (A) is preferably 0.50×10 5 or more, more preferably 1.00 x 10 5 More preferably, 1.50 × 10 5 More preferably, 1.80×10 5 or more, preferably 6.00 × 10 5 or less, more preferably 5.00 x 10 5 or less, more preferably 4.00 × 10 5 or less, and even more preferably 3.50 × 10 5 Below, particularly preferably 3.00 × 10 5 The Mw is, for example, 0.50 × 10 5 Over 6.00 x 10 5 In this specification, the above Mw is obtained by high-temperature GPC measurement, and the detailed conditions are described in the Examples section.

[0046] The density of the high density polyethylene (A) is preferably 0.945 g / cm 3 More preferably, 0.948 g / cm 3 or more, preferably 0.970 g / cm 3 or less, more preferably 0.965 g / cm 3 or less, more preferably 0.960 g / cm 3 The density is, for example, 0.945 g / cm 3 Super 0.970g / cm 3 The high-density polyethylene (A) having such a density contributes to improving the heat resistance of the stretched film, for example.

[0047] The melting point of the high-density polyethylene (A) is preferably within the range described above for the melting point of high-density polyethylene, and particularly preferably not less than 130° C. A high-density polyethylene (A) having such a melting point contributes to improving the heat resistance of a stretched film, for example.

[0048] From the viewpoint of heat resistance, the content of the high-density polyethylene (A) in the film is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0049] The film may contain a polyethylene other than the high-density polyethylene (A). The film may contain a resin material other than polyethylene. Examples of the resin material other than polyethylene include polyolefins other than polyethylene, polyesters, polyamides, (meth)acrylic resins, vinyl resins, cellulose resins, and ionomer resins.

[0050] The film may contain additives such as crosslinkers, antioxidants, UV absorbers, light stabilizers, antiblocking agents, slip agents, fillers, reinforcing agents, antistatic agents, compatibilizers, pigments, and modifying resins.

[0051] The film may be a monolayer film containing high-density polyethylene (A) as a main component. The film may have two or more layers containing high-density polyethylene (A) as a main component, may have from three to nine such layers, may have from three to five such layers, or may have three or five such layers. When adjacent layers constituting the film have the same resin composition and are indistinguishable from one another, the adjacent layers may be integrated to form a single layer.

[0052] A stretched film is a film obtained by stretching the above-mentioned film. Stretching can improve, for example, the strength, rigidity, heat resistance, transparency, and printability of the film. The stretching may be uniaxial stretching or biaxial stretching. The biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching. The stretching method is not particularly limited, but examples include a method in which a film is uniaxially stretched by varying the rotation speed of two or more rolls, a method in which a film is biaxially stretched by a tenter method, and a method in which a film is biaxially stretched by a tubular method.

[0053] The stretching direction of the film is not particularly limited, but examples include the machine direction (flow direction, MD) of the film and the width direction (direction perpendicular to the MD, TD) of the film. When the film is stretched in the machine direction (flow direction, MD), the stretching ratio is preferably 2 or more, more preferably 3 or more, from the viewpoint of improving strength, etc.; and preferably 10 or less, more preferably 7 or less, even more preferably 5 or less, from the viewpoint of excellent thermal shape stability, for example, 2 to 10 or 3 to 5. When the film is stretched in the width direction (direction perpendicular to the MD, TD), the stretching ratio is preferably 2 or more, more preferably 3 or more, from the viewpoint of improving strength, etc.; and preferably 10 or less, more preferably 7 or less, even more preferably 5 or less, from the viewpoint of excellent thermal shape stability, for example, 2 to 10 or 3 to 5. The stretched film is preferably a film obtained by uniaxially stretching the above film, i.e., a uniaxially stretched film, specifically a film obtained by uniaxially stretching the above film in the MD.

[0054] The stretched film can be produced, for example, by forming a material containing high-density polyethylene (A) into the film, and then stretching the film. Examples of film-forming methods include inflation molding and T-die casting, with inflation molding being preferred. When producing the film by inflation molding, the MFR of the polyethylene is preferably 0.01 g / 10 min or more and 15 g / 10 min or less, more preferably 0.05 g / 10 min or more and 10 g / 10 min or less, from the viewpoints of film-forming ability and processability.

[0055] In one embodiment, the film is a coextruded film. In one embodiment, the stretched film is obtained by stretching a co-extruded film, for example, by an inflation molding method or a T-die casting method.

[0056] The stretching temperature in the stretching treatment is not particularly limited. The stretched film may be subjected to a heat setting treatment if necessary. The annealing temperature in the heat setting treatment is not particularly limited.

[0057] The thickness of the film is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, particularly preferably 40 μm or more, and is preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 250 μm or less, particularly preferably 150 μm or less, for example, 10 μm or more and 1000 μm or less.

[0058] The thickness of the stretched film is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 15 μm or more, particularly preferably 20 μm or more, and preferably 200 μm or less, more preferably 100 μm or less, even more preferably 50 μm or less, particularly preferably 30 μm or less, for example, 5 μm or more and 200 μm or less. Stretched films having a thickness equal to or greater than the lower limit exhibit, for example, excellent strength, rigidity, and heat resistance. Stretched films having a thickness equal to or less than the upper limit exhibit, for example, excellent processability. In this specification, the thickness of the film and each layer is the average value of thicknesses measured at 10 points in a scanning electron microscope (SEM) image obtained by observing a cross section of the film in the thickness direction perpendicular to the main surface with an SEM.

[0059] The content of high-density polyethylene (A) in the above-mentioned film and stretched film is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, particularly preferably 85% by mass or more, 90% by mass or more, or 95% by mass or more. Such stretched films and laminates comprising the stretched films have, for example, excellent recyclability.

[0060] At least one selected from the group consisting of the above-mentioned film and stretched film may be subjected to a surface treatment. Such a film and stretched film have, for example, excellent adhesion to other layers. Examples of surface treatment methods include physical treatment and chemical treatment. Examples of physical treatments include corona treatment, ozone treatment, low-temperature plasma treatment using oxygen gas and / or nitrogen gas, and glow discharge treatment. Examples of chemical treatments include oxidation treatment using chemicals.

[0061] <Raman spectroscopy measurement> The stretched film of the present disclosure preferably has a scattering intensity obtained by Raman spectroscopy of the cross section of the film that satisfies the requirements described below. The cross section of the stretched film is a plane parallel to a plane including the thickness direction perpendicular to the main surface of the film and the stretching direction of the film (e.g., MD or TD). The method for obtaining the cross section and details of the Raman spectroscopy are described in the Examples section.

[0062] In Raman spectroscopy, the vertical axis represents the scattering intensity of the Raman scattered light (Intensity), and the horizontal axis represents the Raman shift (cm -1 ) is obtained. In the Raman spectrum, -1 More than 1150cm -1 The maximum scattering intensity of the peak (peak 1) observed in the following region is designated as "I1", especially 1130 cm -1 The maximum scattering intensity of the peak near 1130 " Also, 1050cm -1 More than 1100cm -1 The maximum scattering intensity of the peak (peak 2) observed in the region below 1063 cm is indicated as "I2", and -1 The maximum scattering intensity of the peak near 1063 The maximum scattering intensity (peak intensity) means the height of each peak from the baseline.

[0063] In one embodiment, Peak 1 is attributed to CC symmetric stretching vibration in the trans chain of the polyethylene crystalline phase. The scattering intensity of Peak 1 is likely to change depending on the molecular orientation state of the polyethylene. When the stretching direction and the vibration direction of the excitation light (polarized laser) are parallel, the scattering intensity of Peak 1 becomes strong. A strong scattering intensity of Peak 1 indicates that the orientation of the polyethylene in the stretching direction has progressed.

[0064] In one embodiment, Peak 2 is attributed to the CC antisymmetric stretching vibration of the trans chain of the polyethylene crystalline phase. The scattering intensity of Peak 2 does not show a significant change depending on the molecular orientation state of the polyethylene, and therefore is not significantly affected by the stretching treatment.

[0065] Thus, Peak 1 and Peak 2 differ in the influence of the molecular orientation state. By comparing the scattering intensity I1 and the scattering intensity I2, the molecular orientation of polyethylene due to the stretching treatment can be evaluated. In other words, the molecular orientation of polyethylene can be evaluated using the value of I1 / I2. Polyethylene in a state of high molecular orientation tends to have an I1 / I2 of 1.1 or more. Polyethylene in a state of low molecular orientation tends to have an I1 / I2 of less than 1.1. In one embodiment, I1 / I2 is 1130 / I 1063 is.

[0066] Examples of polyethylenes that are likely to become highly oriented by stretching include high-density polyethylene and medium-density polyethylene. In one embodiment, a layer containing high-density polyethylene and / or medium-density polyethylene as a main component has an I1 / I2 ratio of 1.1 or greater, preferably 1.2 or greater and 4.0 or less, more preferably 1.4 or greater and 3.0 or less, and even more preferably 1.5 or greater and 2.0 or less, after stretching. In such a layer, oriented crystals are aligned, and it can be said that molecular motion is less likely to occur after stretching compared to before stretching.

[0067] Examples of polyethylenes whose orientation changes little upon stretching include linear low-density polyethylene and high-pressure low-density polyethylene. In one embodiment, a layer containing linear low-density polyethylene and / or high-pressure low-density polyethylene as a primary component has an I1 / I2 ratio of less than 1.1 after stretching, preferably 0.5 or more and less than 1.1, more preferably 0.6 or more and less than 1.1, and even more preferably 0.7 or more and less than 1.1. This indicates that despite the stretching treatment of the polyethylene, the orientation of the polyethylene is low or not at all. The stress in an intermediate layer containing linear low-density polyethylene and / or high-pressure low-density polyethylene as a primary component is thought to be small, and it is presumed that the layer does not contribute significantly to shrinkage.

[0068] The I1 / I2 ratio obtained by Raman spectroscopy of the cross section of the stretched film is preferably 1.1 or more, more preferably 1.2 or more and 4.0 or less, even more preferably 1.4 or more and 3.0 or less, and particularly preferably 1.5 or more and 2.0 or less.

[0069] In the case of a uniaxially stretched film stretched in the MD direction, the cross section is a cross section parallel to the MD direction. In the case of a uniaxially stretched film stretched in the TD direction, the cross section is a cross section parallel to the TD direction. In the case of a biaxially stretched film stretched in both the MD and TD directions, the cross sections are a cross section parallel to the MD direction and a cross section parallel to the TD direction, and it is preferable that the stretched film satisfies the above requirements for the scattering intensity ratio for each cross section.

[0070] <Dimensional change rate> In the stretched film of the present disclosure, the dimensional change rate in the stretching direction is preferably −10% or more and 0% or less, more preferably −8% or more and 0% or less, even more preferably −6% or more and 0% or less, still more preferably −4% or more and 0% or less, and particularly preferably −3% or more and 0% or less. The dimensional change rate is measured by hanging a test piece of the stretched film so that the film surface is parallel to the vertical direction and the stretching direction of the film is perpendicular to the vertical direction, and leaving it in an environment of 120° C. for 5 minutes. When the stretched film of the present disclosure is a uniaxially stretched film, the dimensional change rate in the stretching direction (e.g., MD or TD) is preferably within the above range. When the stretched film of the present disclosure is a biaxially stretched film, the dimensional change rate in the stretching direction (e.g., MD and TD) is preferably within the above range. The definition of the dimensional change rate and the conditions for measuring it are described in the Examples section.

[0071] <Maximum dimensional change rate> The maximum dimensional change rate of the stretched film of the present disclosure in the stretching direction in the tensile mode of thermomechanical analysis (TMA) within the range of 20°C to 120°C is preferably -15% or more and 15% or less, more preferably -12% or more and 12% or less, even more preferably -10% or more and 10% or less, still more preferably -8% or more and 8% or less, particularly preferably -6% or more and 6% or less, and especially preferably -4% or more and 4% or less. When the stretched film of the present disclosure is a uniaxially stretched film, the maximum dimensional change rate in the stretching direction (e.g., MD or TD) is preferably within the above range. When the stretched film of the present disclosure is a biaxially stretched film, the maximum dimensional change rate in the stretching direction (e.g., MD and TD) is preferably within the above range. The definition of the maximum dimensional change rate and the measurement conditions are described in the Examples section. Note that, since a load (tensile force) is applied in the TMA measurement, if the load (tensile force) is greater than the force that causes the stretched film to shrink, the maximum dimensional change rate can be an elongation value (positive value).

[0072] <Puncture strength> The puncture strength of the stretched film of the present disclosure is not particularly limited, but is preferably 2.5 N / mmφ or more, more preferably 3.0 N / mmφ or more, even more preferably 3.5 N / mmφ or more, and particularly preferably 4.0 N / mmφ or more. The puncture strength of the stretched film of the present disclosure may be, for example, 10.0 N / mmφ or less, 8.0 N / mmφ or less, or 6.0 N / mmφ or less. The puncture strength is measured in accordance with JIS Z1707:2019, and details of the measurement conditions are described in the Examples section. The puncture strength can be increased, for example, by using high-density polyethylene with high melt tension.

[0073] <1 / 4 width> In one embodiment, the entire polyethylene contained in the film or stretched film of the present disclosure preferably has a peak with a quarter width of less than 1.8 in a differential molecular weight distribution curve obtained by high-temperature GPC measurement. The quarter width may be, for example, less than 1.7. The quarter width is preferably 1.0 or greater. The differential molecular weight distribution curve is measured for the entire polyethylene contained in the film or stretched film. The 1 / 4 width of the entire polyethylene is preferably less than 1.5, more preferably 1.47 or less, even more preferably 1.43 or less, particularly preferably 1.4 or less, more preferably 1.1 or more, and even more preferably 1.2 or more. The 1 / 4 width is, for example, equal to or greater than 1.0 and less than 1.8.

[0074] [Printed film] The printed film of the present disclosure comprises the above-mentioned film or stretched film and a printed layer, specifically, the above-mentioned film or stretched film and a printed layer provided on at least one main surface selected from the group consisting of the first main surface and the second main surface of the film or stretched film.

[0075] The print layer includes an image. Examples of the image include letters, figures, patterns, symbols, and combinations thereof. The image may include text information such as the product name, the name of the item in the packaging container, the manufacturer, and the names of ingredients. The image may be a single, solid color (a so-called solid image).

[0076] The printed layer can be formed, for example, using an ink composition. Methods for forming the printed layer include, for example, gravure printing, offset printing, flexographic printing, screen printing, letterpress printing, and transfer printing. From the viewpoint of reducing the environmental load, the printed layer may be formed by flexographic printing. From the viewpoint of reducing the environmental load, the printed layer may be formed using ink derived from biomass.

[0077] The thickness of the printed layer is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and preferably 10 μm or less, more preferably 5 μm or less, even more preferably 3 μm or less, for example, 0.1 μm or more and 10 μm or less.

[0078] [Barrier film] The barrier film of the present disclosure comprises the above-described film or stretched film and a vapor-deposited film, specifically, the above-described film or stretched film and a vapor-deposited film provided on at least one main surface selected from the group consisting of the first and second main surfaces of the film or stretched film. The barrier film has, for example, excellent gas barrier properties, specifically, excellent oxygen barrier properties and water vapor barrier properties, and, when the vapor-deposited film is a metal vapor-deposited film, excellent brightness. Packaging containers made using such barrier films have excellent gas barrier properties.

[0079] The barrier film may be subjected to the above-mentioned surface treatment, and such a barrier film has, for example, excellent adhesion to other layers.

[0080] <Vapor deposition film> The vapor-deposited film may be composed of, for example, a metal and / or an inorganic oxide. The vapor-deposited film may be a metal vapor-deposited film composed of one or more metals, or an inorganic oxide vapor-deposited film composed of one or more inorganic oxides. The inorganic oxide vapor-deposited film may be a transparent vapor-deposited film. Examples of metals include aluminum, chromium, tin, nickel, copper, silver, gold, and platinum. Examples of inorganic oxides include aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, barium oxide, and silicon carbide oxide (carbon-containing silicon oxide). Among vapor-deposited films, aluminum vapor-deposited films, aluminum oxide (alumina) vapor-deposited films, silicon oxide (silica) vapor-deposited films, and silicon carbide vapor-deposited films are preferred.

[0081] The barrier film may have two or more vapor-deposited films on the above film or stretched film.

[0082] From the viewpoint of gas barrier properties, the thickness of the vapor-deposited film is preferably 1 nm or more, more preferably 5 nm or more, and even more preferably 10 nm or more. From the viewpoint of suppressing cracking in the vapor-deposited film and the recyclability of the packaging container, the thickness of the vapor-deposited film is preferably 150 nm or less, more preferably 100 nm or less, and even more preferably 80 nm or less. The thickness of the vapor-deposited film is, for example, 1 nm or more and 150 nm or less.

[0083] The surface of the vapor-deposited film may be subjected to the above-mentioned surface treatment, which may provide, for example, excellent adhesion to other layers.

[0084] Examples of methods for forming vapor-deposited films include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, and ion plating, as well as chemical vapor deposition (CVD) methods such as plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition. The vapor-deposited film may be a composite film containing two or more different vapor-deposited film layers formed by combining both physical vapor deposition and chemical vapor deposition.

[0085] The vacuum level in the deposition chamber was 10 -2 ~10 -8 After oxygen is introduced, the pressure is preferably about 10 -1 ~10 -6 A pressure of about mbar is preferable. The amount of oxygen introduced varies depending on the size of the deposition machine. The oxygen introduced may be mixed with an inert gas such as argon gas, helium gas, or nitrogen gas as a carrier gas, provided that this does not cause any problems. The transport speed of the target film on which the deposition film is formed is, for example, 10 m / min to 800 m / min.

[0086] The vapor-deposited film may be a single layer formed by a single vapor deposition process, or may be a multilayer formed by multiple vapor deposition processes. When the vapor-deposited film is a multilayer film, each layer may be composed of the same or different components. Each layer may be formed by the same method or by different methods.

[0087] <Barrier coat layer> The barrier film of the present disclosure may further include a barrier coating layer on the vapor-deposited film. That is, the barrier film may further include a barrier coating layer on the surface of the vapor-deposited film opposite to the surface facing the film or stretched film. Such a barrier film has excellent scratch resistance and gas barrier properties, and when the vapor-deposited film is composed of an inorganic oxide such as aluminum oxide or silicon oxide, it can effectively prevent cracks from occurring in the vapor-deposited film and prevent a decrease in gas barrier properties.

[0088] In one embodiment, the barrier coat layer contains a gas barrier resin. A barrier film including such a layer has even better gas barrier properties. The barrier coat layer can be formed, for example, by applying a coating liquid obtained by dissolving or dispersing a material such as a gas barrier resin in water or an appropriate organic solvent to a vapor-deposited film and drying the resulting coating liquid.

[0089] Examples of gas barrier resins include ethylene-vinyl alcohol copolymers, polyvinyl alcohol, polyamides, polyvinylidene chloride, polyesters, polyether polyols, polyester polyols, polyurethanes, polyacrylonitrile, and (meth)acrylic resins.

[0090] In one embodiment, the content of the gas barrier resin in the barrier coat layer is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% by mass or more. Such a layer has, for example, excellent gas barrier properties.

[0091] The barrier coat layer may contain the above-mentioned additives.

[0092] The thickness of the barrier coat layer containing the gas barrier resin is preferably 0.01 μm or more, more preferably 0.1 μm or more, from the viewpoint of gas barrier properties. The thickness of the barrier coat layer containing the gas barrier resin is preferably 10 μm or less, more preferably 5 μm or less, from the viewpoint of processability of the barrier film and recyclability of the packaging container. The thickness is, for example, 0.01 μm or more and 10 μm or less.

[0093] In another embodiment, the barrier coat layer is a gas barrier coating film formed by applying a gas barrier composition to a vapor-deposited film and drying it. The gas barrier composition is obtained by mixing a metal alkoxide, a water-soluble polymer, and optionally a silane coupling agent, and adding, optionally, water, optionally an organic solvent, and optionally a sol-gel catalyst. The gas barrier coating film contains a hydrolysis polycondensate obtained by hydrolyzing and polycondensing the metal alkoxide or the like by a sol-gel method. By providing such a film on a vapor-deposited film, when the vapor-deposited film is composed of an inorganic oxide, the gas barrier properties can be improved and the occurrence of cracks in the vapor-deposited film can be effectively suppressed.

[0094] Examples of metal alkoxides include alkoxysilanes, specifically tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

[0095] Examples of water-soluble polymers include hydroxyl group-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers. These water-soluble polymers can also contribute to improving gas barrier properties, for example. Depending on the desired physical properties, such as oxygen barrier properties, water vapor barrier properties, water resistance, and weather resistance, either polyvinyl alcohol or ethylene-vinyl alcohol copolymers may be used, or both may be used in combination. Furthermore, a gas barrier coating film obtained using polyvinyl alcohol and a gas barrier coating film obtained using an ethylene-vinyl alcohol copolymer may be laminated. The amount of water-soluble polymer used is preferably 5 to 500 parts by mass per 100 parts by mass of the metal alkoxide.

[0096] As the silane coupling agent, a known organoalkoxysilane containing an organic reactive group can be used, and an organoalkoxysilane having an epoxy group is preferred, such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. The amount of the silane coupling agent used is preferably 1 part by mass or more and 20 parts by mass or less per 100 parts by mass of the metal alkoxide.

[0097] The gas barrier composition may contain water in an amount of preferably 0.1 mol or more, more preferably 0.5 mol or more, per mol of metal alkoxide, and preferably 100 mol or less, more preferably 60 mol or less. By setting the water content at or above the lower limit, for example, the oxygen barrier property and water vapor barrier property of the barrier film can be improved. By setting the water content at or below the upper limit, for example, the hydrolysis reaction can be carried out quickly.

[0098] The gas barrier composition may contain an organic solvent, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, or n-butyl alcohol.

[0099] The sol-gel catalyst is preferably an acid or an amine compound.

[0100] Examples of methods for applying the gas barrier composition include roll coating using a gravure roll coater or the like, spray coating, spin coating, dipping, brush coating, bar coating, and applicator coating.

[0101] Hereinafter, one embodiment of the method for forming a gas barrier coating film will be described. A gas barrier composition is prepared by mixing a metal alkoxide, a water-soluble polymer, a sol-gel catalyst, water, an organic solvent, and, if necessary, a silane coupling agent. A polycondensation reaction gradually progresses within the composition. The composition is then coated onto the vapor-deposited film by a conventional method and dried. This drying process further promotes polycondensation of the metal alkoxide and the water-soluble polymer (and the silane coupling agent, if the composition contains one) to form a composite polymer layer. Multiple composite polymer layers may be laminated by repeating the above process. For example, the coated composition is heated at a temperature of preferably 20°C or higher, more preferably 50°C or higher, and even more preferably 70°C or higher, and preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower, for 1 second to 10 minutes. In this manner, a gas barrier coating film can be formed.

[0102] The thickness of the gas barrier coating film is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, and is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 5 μm or less, still more preferably 2 μm or less, and particularly preferably 1 μm or less, for example, 0.01 μm or more and 100 μm or less. A barrier film having such a gas barrier coating film has, for example, excellent gas barrier properties, can suppress the occurrence of cracks in a vapor-deposited film made of an inorganic oxide, and also provides excellent recyclability and processability of the packaging container.

[0103] <Print layer> The barrier film of the present disclosure may further include the above-described printed layer. The printed layer may be provided, for example, on at least one main surface selected from the group consisting of the first and second main surfaces of the film or stretched film, on the surface of the vapor-deposited film, or on the surface of the barrier coat layer.

[0104] [Application] At least one film selected from the group consisting of the above-described film, stretched film, printed film, and barrier film of the present disclosure will be referred to as the "film of the present disclosure." The film of the present disclosure can be suitably used as a substrate constituting a packaging material. Because the film of the present disclosure has high heat resistance, it can be suitably used as a printing substrate.

[0105] [Laminate] The laminate of the present disclosure comprises at least a film of the present disclosure; a heat seal layer; are provided in this order in the stacking direction. In one embodiment, the laminate of the present disclosure comprises at least a first heat seal layer; a film of the present disclosure; a second heat seal layer; and are provided in this order in the stacking direction.

[0106] The laminate of the present disclosure can be suitably used as a packaging material. The laminate of the present disclosure, which includes the first and second heat-sealing layers, can be suitably used, for example, as a packaging material for forming the body of a tube container. In this case, for example, the second heat-sealing layer is a sealant layer on the outer surface of the body, and the first heat-sealing layer is a sealant layer on the inner surface of the body. That is, the body includes, from the outside to the inside of the body, the second heat-sealing layer, the film of the present disclosure, and the first heat-sealing layer, in this order.

[0107] In one embodiment, the laminate of the present disclosure does not include aluminum foil. In one embodiment, the laminate of the present disclosure does not include either a polyethylene terephthalate film or aluminum foil. Such a laminate and a packaging container including the laminate have excellent recyclability.

[0108] In one embodiment, the total thickness of the laminate of the present disclosure may be 40 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, 120 μm or more, 140 μm or more, 400 μm or less, 350 μm or less, or 300 μm or less, for example, 40 μm or more and 400 μm or less. The total thickness of the laminate can be changed as appropriate depending on, for example, the use or shape of the packaging container.

[0109] <Base material> The laminate of the present disclosure includes the film of the present disclosure as a substrate. The laminate of the present disclosure may include two or more films of the present disclosure. Details of these films are as described above, and detailed description will be omitted here.

[0110] The laminate of the present disclosure may further include a polyolefin oriented substrate other than the above-described stretched film. The polyolefin oriented substrate is a polyolefin substrate that has been subjected to a stretching treatment. The polyolefin oriented substrate contains polyolefin as a main component. Examples of polyolefins include polyethylene, polypropylene, polybutene, and polymethylpentene. Among these, polyethylene and polypropylene are preferred, with polyethylene being more preferred. Examples of the polyolefin oriented substrate include a polyethylene oriented substrate containing polyethylene as a main component and a polypropylene oriented substrate containing polypropylene as a main component, with a polyethylene oriented substrate being more preferred. The stretching treatment may be uniaxial or biaxial. Details of the stretching treatment are as described above, and will not be described here. The polyolefin oriented substrate may be, for example, a uniaxial or biaxially stretched substrate.

[0111] The oriented polyolefin substrate may contain a biomass polyolefin. The oriented polyolefin substrate may contain recycled polyolefin. The oriented polyolefin substrate may contain the above-mentioned additives.

[0112] The polyolefin content in the oriented polyolefin substrate is 50% by mass or more, preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0113] The oriented polyolefin substrate may have a single layer structure or a multilayer structure. The thickness of the oriented polyolefin substrate is preferably 5 μm or more, more preferably 8 μm or more, and even more preferably 10 μm or more, from the viewpoint of the strength and heat resistance of the laminate, and is preferably 300 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less, for example, 5 μm or more and 300 μm or less, from the viewpoint of the processability of the laminate.

[0114] The oriented polyolefin substrate may be subjected to the above-mentioned surface treatment. Such an oriented polyolefin substrate has, for example, excellent adhesion to a layer adjacent to the substrate. An anchor coating layer may be formed on the surface of the oriented polyolefin substrate using a conventionally known anchor coating agent.

[0115] The laminate further comprising an oriented polyolefin substrate may, for example, comprise a heat seal layer, a film of the present disclosure, and an oriented polyolefin substrate in this order, or may comprise a heat seal layer, an oriented polyolefin substrate, and a film of the present disclosure in this order.

[0116] <Print layer> The laminate of the present disclosure may have a printed layer on one or both sides of the substrate, such as the film of the present disclosure and a polyolefin stretched substrate. The laminate of the present disclosure may have a printed layer on the second heat-sealable layer described below. Details of the printed layer are as described above, and will not be described here.

[0117] <Heat seal layer> The laminate of the present disclosure comprises a heat seal layer. The heat-seal layer contains, as its main component, a heat-sealable resin that can melt and fuse together when heated. Examples of heat-sealable resins include polyolefins such as polyethylene, polypropylene, and polymethylpentene, cyclic polyolefins, cyclic olefin copolymers, ionomer resins, acid-modified polyolefins, and ethylene-(meth)acrylic acid ester-unsaturated carboxylic acid terpolymers. Examples of polyethylene include linear low-density polyethylene, high-pressure low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ethylene-(meth)acrylic acid ester copolymer. Examples of acid-modified polyolefins include resins obtained by modifying polyolefins such as polyethylene and polypropylene with unsaturated carboxylic acid compounds such as (meth)acrylic acid and maleic anhydride. The heat-sealable resin may be derived from fossil fuels, biomass, or both.

[0118] In recent years, there has been a demand for recycling packaging containers in order to reduce environmental impact. From the viewpoint of recyclability, it is preferable that the substrate and the heat seal layer are each made of the same type of resin material (mono-material). In one embodiment, the heat seal layer contains polyethylene as a main component. This configuration enables the packaging container to be made mono-material. Such packaging containers have excellent recyclability, and for example, after collecting used packaging containers, there is no need to separate the substrate and the heat seal layer.

[0119] From the viewpoint of heat-sealability, the heat-seal layer preferably contains high-pressure low-density polyethylene and / or linear low-density polyethylene. When the heat-seal layer contains high-pressure low-density polyethylene and linear low-density polyethylene, the content (mass%) of the linear low-density polyethylene may be greater than the content (mass%) of the high-pressure low-density polyethylene.

[0120] From the viewpoint of a balance between heat resistance and heat sealability, the melting point of the polyethylene contained in the heat seal layer is preferably 90°C or higher, more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, for example, 90°C or higher and 140°C or lower.

[0121] In one embodiment, the polyethylene content in the heat seal layer is 50% by mass or more. The content is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, still more preferably 90% by mass or more, and particularly preferably 95% by mass or more. A laminate including such a heat seal layer has excellent recyclability, for example.

[0122] The heat seal layer may contain the above-mentioned additives.

[0123] In one embodiment, the polyethylene content in the entire laminate of the present disclosure is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more. Such a laminate has excellent recyclability, for example. For example, the laminate can be used to produce a mono-material packaging container, thereby improving the recyclability of the packaging container.

[0124] The laminate of the present disclosure may include a first heat-sealing layer as the heat-sealing layer, a film of the present disclosure, and a second heat-sealing layer as the heat-sealing layer, in this order in the lamination direction. The first heat-sealing layer and the second heat-sealing layer can be melted and fused to each other by heating. Such a laminate can be suitably used, for example, as a packaging material for forming the body of a tube container.

[0125] In one embodiment, the first and second heat-seal layers contain polyethylene as a main component, and the polyethylene contained in the first heat-seal layer and the polyethylene contained in the second heat-seal layer may be the same or different.

[0126] The heat seal layer may have a single-layer structure or a multi-layer structure. The first and second heat seal layers may have a single-layer structure or a multi-layer structure.

[0127] The thickness of the heat seal layer may be 10 μm or more, 20 μm or more, 30 μm or more, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more from the viewpoint of heat sealing properties and recyclability of the packaging container. The thickness of the heat seal layer may be 300 μm or less, 200 μm or less, or 150 μm or less from the viewpoint of processability of the laminate. The thickness of the heat seal layer is, for example, 10 μm or more and 300 μm or less. The thicknesses of the first and second heat seal layers are also preferably independently within the above ranges. The thickness of the heat seal layer can be appropriately changed depending on, for example, the use or shape of the packaging container. In the case of a small bag, the thickness of the heat seal layer may be, for example, 20 μm or more and 60 μm or less, but is not particularly limited. In the case of a standing pouch, the thickness of the heat seal layer may be, for example, 60 μm or more and 150 μm or less, but is not particularly limited. In the case of a tube container, the thickness of each heat seal layer may be, for example, 50 μm or more, 60 μm or more, 70 μm or more, or 80 μm or more, but is not particularly limited.

[0128] From the viewpoint of heat sealing property, the heat seal layer is preferably an unstretched resin film, more preferably an unstretched co-extruded resin film, and each layer constituting the heat seal layer is a co-extruded resin layer. The above resin film can be produced, for example, by using a T-die casting method or an inflation molding method. The concept of "unstretched film" includes not only a film that is not stretched at all, but also a film that is slightly stretched due to the tension applied during film formation.

[0129] For example, an unstretched resin film corresponding to the heat seal layer may be laminated on the film of the present disclosure via an adhesive layer as needed, or a heat-sealable resin or a resin composition thereof may be melt-extruded onto the film of the present disclosure to form the heat seal layer. In the latter case, an adhesive layer may not be provided. Examples of adhesive layers include the following adhesive layers.

[0130] <Adhesive layer> The laminate of the present disclosure may include an adhesive layer between any layers, such as between a substrate such as a film of the present disclosure and a heat seal layer. Such a laminate has, for example, excellent adhesion between the substrate and the heat seal layer.

[0131] The laminate of the present disclosure may, for example, comprise a heat-sealing layer, an adhesive layer, and a film of the present disclosure in this order in the lamination direction, or a heat-sealing layer, a first adhesive layer, a film of the present disclosure, a second adhesive layer, and a stretched polyolefin substrate in this order in the lamination direction, or a heat-sealing layer, a first adhesive layer, a stretched polyolefin substrate, a second adhesive layer, and a film of the present disclosure in this order in the lamination direction.The laminate of the present disclosure may, for example, comprise a first heat-sealing layer, a first adhesive layer, a film of the present disclosure, a second adhesive layer, and a second heat-sealing layer in this order in the lamination direction.

[0132] In one embodiment, the adhesive layer may be an adhesive layer made of an adhesive. The adhesive may be any of a one-component curing adhesive, a two-component curing adhesive, and a non-curing adhesive. The adhesive may be a solventless adhesive or a solvent-based adhesive. Among these, a solvent-based adhesive is preferred because it has better resistance to contents.

[0133] Examples of solvent-free adhesives, i.e., non-solvent laminate adhesives, include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, urethane adhesives are preferred, and two-component curing urethane adhesives are more preferred.

[0134] Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are more preferred.

[0135] In one embodiment, the laminate of the present disclosure may be produced by laminating the film of the present disclosure, an optionally stretched polyolefin substrate, and a resin film corresponding to the heat seal layer by a non-solvent lamination method using a solvent-free adhesive, or by a dry lamination method using a solvent-based adhesive. The adhesive layer can be formed by applying an adhesive to the film of the present disclosure or the like by a method such as direct gravure roll coating, gravure roll coating, kiss coating, reverse roll coating, Fontaine coating, or transfer roll coating, and then drying the adhesive.

[0136] The thickness of the adhesive layer may be 0.1 μm or more, 0.2 μm or more, 0.5 μm or more, 10 μm or less, 8 μm or less, or 6 μm or less, for example, 0.1 μm or more and 10 μm or less. The thickness of the adhesive layer may be 2 μm or less.

[0137] In one embodiment, the adhesive layer may be an adhesive resin layer containing a thermoplastic resin, or an extruded resin layer containing a thermoplastic resin. Examples of the thermoplastic resin include the above-mentioned heat-sealable resins. The thermoplastic resin may be a material derived from fossil fuels, a material derived from biomass, or both.

[0138] The thickness of the extruded resin layer is preferably 5 μm or more, more preferably 10 μm or more, from the viewpoint of interlayer adhesion. The thickness of the extruded resin layer is preferably 30 μm or less, more preferably 25 μm or less, from the viewpoint of reducing the production cost of the laminate and improving its productivity. The thickness of the extruded resin layer is, for example, 5 μm or more and 30 μm or less.

[0139] <Layer structure of laminate> Hereinafter, several examples of the layer configuration of the laminate of the present disclosure will be given with reference to the drawings. 2 includes, in this order in the stacking direction, a heat seal layer 80, an adhesive layer 60, and a stretched film 1. The laminate 2 may further include a printed layer (not shown), for example, a printed layer may be further provided on the stretched film 1.

[0140] 3 includes, in this order in the stacking direction, a heat seal layer 80, a first adhesive layer 61, a stretched film 1, a second adhesive layer 62, and a stretched polyolefin substrate 70. The laminate 2 may further include a printed layer (not shown), for example, a printed layer may further be provided on the stretched polyolefin substrate 70.

[0141] 4 includes a first heat-seal layer 81, a first adhesive layer 61, a stretched film 1, a second adhesive layer 62, and a second heat-seal layer 82, in this order in the stacking direction. The laminate 2 may further include a printed layer (not shown), for example, a printed layer on the second heat-seal layer 82. A laminate having such a configuration is suitable, for example, as a packaging material for forming the barrel of a tube container body.

[0142] 2 to 4, the above-mentioned film, printed film or barrier film may be provided instead of the stretched film 1. In Figures 2 to 4, adhesive layers 60, 61, 62 may be, for example, adhesive layers or extruded resin layers.

[0143] [Packaging container] The laminate of the present disclosure can be suitably used for packaging material applications. The packaging material is used to produce packaging containers. Examples of packaging containers include packaging bags, tube containers, and containers with lids.

[0144] Examples of packaging bags include various types of packaging bags, such as stand-up pouch type, side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, grommed seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, and gusset type.The packaging bag may be, for example, a small pouch or a zipper bag.The packaging bag may also be a refill pouch, particularly a stand-up pouch, that contains contents such as liquids and powders and is refilled into containers such as bottles.The packaging bag may also be, for example, a flexible packaging bag.

[0145] The packaging container of the present disclosure comprises the laminate of the present disclosure. The packaging container of the present disclosure may be, for example: one or more laminates of the present disclosure; a seal portion where the heat seal layers of the laminate are joined together; a storage section for storing contents; It has. The seal portion includes an inner edge that defines the receptacle portion.

[0146] Examples of methods for forming the sealed portion include heat sealing, which involves melting the heat-sealed layers of the laminate by heating or the like to fuse the heat-sealed layers together, and specific examples include bar sealing, rotary roll sealing, belt sealing, impulse sealing, high-frequency sealing, and ultrasonic sealing. For example, after placing the contents in a packaging bag, the opening of the packaging bag can be heat-sealed to seal the packaging bag.

[0147] The packaging bag may have an easy-to-open portion. Examples of the easy-to-open portion include a notch portion that serves as a starting point for tearing the packaging bag, and a half-cut line formed by laser processing or a cutter as a path for tearing the packaging bag.

[0148] In one embodiment, the laminate of the present disclosure is used as a lid material in a lidded container. The lidded container comprises a container body having a storage compartment and a lid material joined (heat sealed) to the container body so as to seal the storage compartment. Here, the lid material, i.e., the heat seal layer of the laminate, and the container body are heat sealed. Examples of the shape of the container body include a cup shape and a cylindrical shape with a bottom. The container body is made of, for example, polystyrene, polypropylene, polyethylene, or paper.

[0149] Examples of contents housed in packaging containers include liquids, solids, powders, and gels. The contents may be food or beverages, or non-food or beverages such as chemicals, cosmetics, pharmaceuticals, metal parts, and electronic components. Examples of contents include shampoo, rinse, conditioner, hand soap, body soap, air fresheners, deodorants, insect repellents, fabric softeners, detergents; sauces, soy sauce, dressings, cooking oils, mayonnaise, ketchup, syrups, cooking alcohol, and other liquid or viscous condiments; fruit juices; spices; liquid beverages, jelly-like beverages, liquid soups, powdered soups, instant foods, other food and beverages; creams; toothpaste; toothpaste; metal parts, and electronic components. For example, toothpaste and toothpaste are preferred contents for tube containers.

[0150] In one embodiment, a packaging bag can be produced by folding the laminate of the present disclosure in half and overlapping it so that the film of the present disclosure is on the outside and the heat seal layer is on the inside, and then heat sealing the edges, etc. In another embodiment, a packaging bag can be produced by overlapping multiple laminates of the present disclosure so that the heat seal layers face each other and heat sealing the edges, etc. The entire packaging bag may be composed of the above-mentioned laminate, or only a portion of the packaging bag may be composed of the above-mentioned laminate.

[0151] In one embodiment, the stand-up pouch comprises a body portion composed of side sheets and a bottom portion composed of a bottom sheet. The bottom sheet maintains the shape of the side sheets, thereby imparting self-supporting properties to the pouch and enabling it to be a stand-up pouch. A storage compartment for storing contents is formed within the area surrounded by the side sheets and the bottom sheet. In the stand-up pouch, only the side sheets may be the laminate of the present disclosure, only the bottom sheet may be the laminate of the present disclosure, or both the side sheets and the bottom sheet may be the laminate of the present disclosure.

[0152] In one embodiment, the side sheet can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, and heat-sealing both side edges to form a bag.

[0153] In another embodiment, the side sheets can be formed by preparing two laminates of the present disclosure, overlapping them with their heat-sealable layers facing each other, inserting two V-folded laminates with their heat-sealable layers facing outward between the laminates at the side edges of both sides of the overlapped laminates, and heat-sealing the two laminates. This production method produces a stand-up pouch having a body with side gussets.

[0154] In one embodiment, the bottom sheet can be formed by inserting the laminate of the present disclosure between the lower portions of the side sheets of a bag and heat-sealing the laminate. More specifically, the bottom sheet can be formed by inserting the laminate folded in a V-shape with the heat-seal layer facing outward between the lower portions of the side sheets of a bag and heat-sealing the laminate.

[0155] In one embodiment, two laminates of the present disclosure are prepared and stacked together with their heat-sealable layers facing each other. Then, another laminate of the present disclosure is folded in a V-shape with its heat-sealable layer facing outward, and this is sandwiched between the two laminates and heat-sealed to form a bottom. Next, two sides adjacent to the bottom are heat-sealed to form a body. In this manner, a stand-up pouch according to one embodiment can be formed.

[0156] Hereinafter, a case where the laminate of the present disclosure is applied to a tube container body constituting a tube container will be described. The tube container body includes the laminate of the present disclosure. The tube container body includes a head and a body, and for example, the body is formed from the laminate of the present disclosure.

[0157] The head portion has a shoulder portion connected to one end of the body portion, and a spout portion connected to the shoulder portion. In one embodiment, the spout portion has threads for threading a cap thereon.

[0158] In one embodiment, the head portion is formed from a resin composition containing a thermoplastic resin. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene, polyesters, cellulose resins, and vinyl resins. The resin composition may contain the additives described above. In one embodiment, the head portion is formed from a resin composition containing polyethylene. This configuration improves the recyclability of the tube container body. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, high-pressure low-density polyethylene, and linear low-density polyethylene. Among these, high-density polyethylene is preferred from the viewpoints of shape retention and moldability. The resin composition may contain at least one selected from the group consisting of biomass polyethylene and recycled polyethylene.

[0159] The head portion can be produced by a conventionally known method, for example, by compression molding or injection molding, and can be joined to the body portion.

[0160] In the tube container body, the body is connected to the shoulder of the head. The body has a fused portion formed, for example, by overlapping the laminate of the present disclosure so that the surface of the first heat-seal layer at one end and the surface of the second heat-seal layer at the other end are in contact, rolling the laminate into a cylindrical shape, and heat-sealing the overlapped portion. The body has a bottom seal portion formed, for example, by heat-sealing the opening of the laminate rolled into a cylindrical shape.

[0161] Examples of heat sealing methods include conventionally known methods such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing, ultrasonic sealing, and flame sealing.

[0162] For example, a cylindrical body portion may be produced by overlapping one end of the laminate of the present disclosure so that the surface of the first heat-seal layer at one end is in contact with the surface of the second heat-seal layer at the other end, rolling the laminate into a cylindrical shape, and heat-sealing the overlapped portion. From the viewpoint of heat-sealability, it is preferable that one overlapping end is the first heat-seal layer and the other end is the second heat-seal layer. In this case, the first heat-seal layer and the second heat-seal layer are melted and joined to form a fused portion.

[0163] In the above embodiment, the fused portion is formed by overlapping. Alternatively, the same surfaces of both ends of the laminate may be butted together and the first heat-seal layers may be heat-sealed to join them. In this case, a joining tape may be applied to the outer surface of the body portion so as to cover the joining portion.

[0164] The tube container comprises a tube container body and a cap attached to the top. The cap is detachably attached to the spout of the head and serves to close the spout. In one embodiment, the cap is formed from a resin composition containing a thermoplastic resin. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene, polyesters, cellulose resins, and vinyl resins. From the viewpoint of recyclability, polyethylene is particularly preferred. Examples of polyethylene include high-density polyethylene, medium-density polyethylene, low-density polyethylene, linear low-density polyethylene, and very low-density polyethylene. Among these, high-density polyethylene is preferred from the viewpoint of shape retention and ease of opening. The resin composition may contain at least one selected from biomass polyethylene and recycled polyethylene. The resin composition may also contain the additives described above.

[0165] The cap may be a screw type having a groove on the inner surface thereof that fits onto the threads of the extraction spout, or may be a stopper type that fits onto the extraction spout by tapping it.

[0166] [Example of situation] The present disclosure relates to, for example, the following [1] to

[18] . [1] A film containing, as a main component, a high-density polyethylene (A) that satisfies at least one requirement selected from the group consisting of the following (1) and (2): (1) The high-density polyethylene (A) has a peak with a full-width at quarter-maximum (FWQM) value of less than 1.5 in a differential molecular weight distribution curve (horizontal axis: common logarithm (LogM) of molecular weight (M); vertical axis: value dW / d(LogM) obtained by differentiating cumulative concentration fraction (W) with common logarithm of molecular weight (M)) obtained by high-temperature gel permeation chromatography (GPC) measurement; (2) The 90th percentile value (LogM) of the molecular weight distribution in the differential molecular weight distribution curve of the high-density polyethylene (A). 90 ) and the 10th percentile (LogM 10 ) and the difference (LogM 90-LogM 10 ) is less than 1.25. [2] The film according to [1] above, wherein the high-density polyethylene (A) satisfies at least one requirement selected from the group consisting of the following (3) and (4): (3) The peak of the high-density polyethylene (A) has a maximum dW / d(LogM) value of 0.80 or more in the differential molecular weight distribution curve; (4) The high-density polyethylene (A) has a density of 0.945 g / cm 3 Super 0.970g / cm 3 and / or a melting point of 125°C or higher and 140°C or lower. [3] The film according to [1] or [2], which is a monolayer film containing the high-density polyethylene (A) as a main component. [4] The film according to any one of the above [1] to [3], which comprises two or more layers containing the high-density polyethylene (A) as a main component. [5] The film according to any one of the above [1] to [4], which is a substrate. [6] The film according to any one of the above [1] to [5], which is a printing substrate. [7] A stretched film obtained by stretching the film according to any one of the above [1] to [6]. [8] The stretched film according to [7], wherein the stretched film is a uniaxially stretched film. [9] The scattering intensity ratio I1 / I2 obtained by Raman spectroscopy in a cross section of the stretched film is 1.1 or more; the cross section is a plane parallel to a plane including a thickness direction perpendicular to a main surface of the stretched film and a stretching direction of the stretched film, The I1 is detected by Raman spectroscopy at 1100 cm -1 More than 1150cm -1 The maximum scattering intensity of the peak observed in the following region is 1050 cm in Raman spectroscopy. -1 More than 1100cm -1 is the maximum scattering intensity of the peak observed in the region less than The stretched film according to [7] or [8] above.

[10] The stretched film according to any one of [7] to [9], wherein a test piece of the stretched film is hung so that the film surface is parallel to the vertical direction and the stretching direction of the film is perpendicular to the vertical direction, and left in an environment of 120°C for 5 minutes, and the dimensional change rate in the stretching direction is measured to be -10% or more and 0% or less.

[11] The stretched film according to any one of [7] to

[10] , wherein the maximum dimensional change rate in the stretched direction in a tensile mode of thermomechanical analysis (TMA) within a temperature range of 20°C to 120°C is -15% or more and 15% or less.

[12] The stretched film according to any one of [7] to

[11] , wherein the entire polyethylene contained in the stretched film has a peak with an FWQM value of less than 1.8 in a differential molecular weight distribution curve obtained by high-temperature GPC measurement.

[13] The stretched film according to any one of the above [7] to

[12] , which is a substrate.

[14] The stretched film according to any one of the above [7] to

[13] , which is a printing substrate.

[15] A laminate comprising at least one film selected from the group consisting of the film according to any one of [1] to [6] above and the stretched film according to any one of [7] to

[14] above, and a heat seal layer.

[16] The laminate according to

[15] , wherein the heat seal layer contains polyethylene as a main component, and the content of polyethylene in the entire laminate is 80% by mass or more.

[17] A packaging container comprising the laminate according to

[15] or

[16] .

[18] The packaging container according to

[17] , which is a packaging bag. [Example]

[0167] The film and stretched film of the present disclosure will be described in more detail below using examples, but the film and stretched film are not limited to the following examples in any way.

[0168] [Differential molecular weight distribution curve] The differential molecular weight distribution curve of polyethylene was obtained by high-temperature gel permeation chromatography (GPC) measurement as follows. Polyethylene was dissolved in o-dichlorobenzene (containing 0.025 wt% BHT) at 145°C under the conditions of standing for 1 hour and stirring for 1 hour. The resulting solution was pressure-filtered using a membrane filter with a pore size of 1.0 μm and a membrane filter with a pore size of 0.5 μm. High-temperature GPC measurement was performed using the pressure-filtered solution under the following conditions. The cumulative concentration fraction (the mass proportion of polyethylene below a certain molecular weight in total polyethylene) was calculated from the obtained data, and an integrated molecular weight distribution curve was obtained with the horizontal axis representing the common logarithm of the molecular weight in terms of polystyrene and the vertical axis representing the cumulative concentration fraction. Next, a differential molecular weight distribution curve was obtained with the horizontal axis representing the common logarithm of the molecular weight in terms of polystyrene and the vertical axis representing the value (dW / d(LogM)) obtained by differentiating the cumulative concentration fraction by the common logarithm of the molecular weight in terms of polystyrene. (conditions) Equipment: Senshu Scientific SSC-7120 HT-GPC System Sample amount: Approximately 3 mg of sample pieces per 3 mL of solvent ·Injection volume: 300μL Guard column: guard column HHR-H(S)HT2 Separation column: GMHHR-H(S)HT2 (2 columns, inner diameter: 7.8 mm) Column temperature: 145℃ Mobile phase: o-dichlorobenzene (containing 0.025 wt% BHT) ·Flow rate: 0.95mL / min Detector: Differential refractometer Molecular weight calibration: Polystyrene equivalent

[0169] The quarter width of the peak appearing in the differential molecular weight distribution curve and the maximum value of dW / d(LogM) (peak top value) were calculated. The 10th percentile of the differential molecular weight distribution was calculated as the common logarithm of the molecular weight when the cumulative concentration fraction in the integrated molecular weight distribution curve was 10% by mass. The 90th percentile of the differential molecular weight distribution was calculated as the common logarithm of the molecular weight when the cumulative concentration fraction in the integrated molecular weight distribution curve was 90% by mass. Regarding the maximum value (peak top value) of dW / d(LogM) in the differential molecular weight distribution curve, if the peak top value is not clearly indicated on the data representing the differential molecular weight distribution curve, the peak top value can be determined from an approximate equation. In this case, the peak top value can be determined from an approximate equation of a sixth-order polynomial that passes through the maximum data of dW / d(LogM) and four points before and after it (total of nine points). The peaks of the differential molecular weight distribution obtained by high-temperature GPC measurement of polyethylene were examined. Polyethylenes with a peak of 1 / 4 width less than 1.5 in the differential molecular weight distribution, or polyethylenes with a difference between the 90th and 10th percentile values ​​of less than 1.25, were judged to have a "narrow molecular weight distribution" (sharp shape). Polyethylenes with a peak of 1 / 4 width of 1.5 or more in the differential molecular weight distribution, or polyethylenes with a difference between the 90th and 10th percentile values ​​of 1.25 or more, were judged to have a "broad molecular weight distribution" (broad shape). The weight average molecular weight (Mw) of the polyethylene was obtained by the above-mentioned high-temperature GPC measurement.

[0170] [Polyethylene film and oriented film materials] The following materials were used in the preparation of the polyethylene film and stretched film. [Table 1]

[0171] [Example 1] HDPE(A)(FY13) was co-extruded into a tubular shape using an inflation molding method with a layer thickness ratio of HDPE(A) layer (17.0 μm) / HDPE(A) layer (9.5 μm) / HDPE(A) layer (22.0 μm) / HDPE(A) layer (9.5 μm) / HDPE(A) layer (17.0 μm) at a die temperature of 200°C to obtain a 75 μm-thick polyethylene film (a monolayer film composed of HDPE(A)). The tubular polyethylene film was folded at the nip to form two layers. The polyethylene film produced above was stretched in the machine direction (MD) at a stretching temperature of 125°C by a stretching ratio of 3x and then heat-set at an annealing temperature of 125°C. The end was then slit to separate the film into two, resulting in a 25 μm-thick stretched film.

[0172] [Examples 2 to 6, Comparative Examples 1 to 4] Polyethylene films and stretched films were produced in the same manner as in Example 1, except that at least one selected from the group consisting of the type of resin constituting each layer, the thickness of each layer, and the stretch ratio was changed as shown in the table below. In this specification, "←" in the table means that the composition of the layer in question is the same as the composition in the column to the left.

[0173] [Heat resistance evaluation (appearance)] The stretched films obtained in the Examples and Comparative Examples were cut into 10 cm x 10 cm pieces to obtain test pieces. Using a heat seal tester TP-701 (manufactured by Tester Sangyo Co., Ltd.), pressure was applied to a 1 cm (MD) x 10 cm (TD) area of ​​the test piece under the following heat sealer conditions: temperature: 120°C or 130°C, pressure: 0.1 MPa, pressure time: 1 second, and single-sided heating. The presence or absence of shrinkage in this area was visually evaluated according to the following criteria. <Verdict> A: The stretched film is not shrinking. B: The stretched film has shrunk slightly. C: The stretched film has shrunk significantly.

[0174] [Heat resistance evaluation (dimensional change rate in the stretching direction)] The stretched films obtained in the Examples or Comparative Examples were cut to a size of 5 cm x 5 cm to obtain test specimens. A line of approximately 5 cm was drawn on the surface of the test specimen along the stretching direction of the stretched film (MD direction in the above Examples or Comparative Examples), and the dimensions of the line were measured using a precision measurement glass scale S1004 (manufactured by Shibuya Optical Co., Ltd.). Hereinafter, these dimensions will also be referred to as "dimensions before heat treatment." A DY301 (manufactured by Yamato Scientific Co., Ltd.) was used as a heat treatment device. The test specimen was suspended in a thermostatic chamber so that the film surface was parallel to the vertical direction (direction of gravity) and the stretching direction of the film was perpendicular to the vertical direction, and left in an environment of 120°C for 5 minutes, thereby performing heat treatment. The dimensions of the line on the test specimen after heat treatment were measured using the glass scale. Hereinafter, these dimensions will also be referred to as "dimensions after heat treatment." The dimensional change rate in the stretching direction was calculated from the obtained dimensions before and after heat treatment. Dimensional change rate (%) = ((dimension after heat treatment - dimension before heat treatment) / dimension before heat treatment)) x 100 Elongation: The dimensional change rate shows a positive value. Shrinkage: The dimensional change rate shows a negative value.

[0175] [Heat resistance evaluation (maximum dimensional change rate in the stretching direction)] The dimensional change rate (ΔL) of the stretched film in the stretching direction was measured by the tensile mode of thermomechanical analysis (TMA). In measuring the dimensional change rate, a tensile force was applied to a stretched film sample held between chucks. Next, the dimensional change rate of the sample was measured while the environment surrounding the sample was changed in the following order of temperature drop and temperature rise. The dimensional change rate was calculated from the dimensions of the sample during the temperature rise step.

[0176] The specific conditions are as follows: Equipment: TMA-SS7100 (Hitachi High-Tech Science) Sample length between chucks: 10mm Sample width: 5mm Tensile force: 100mN Atmospheric gas: Nitrogen

[0177] Cooling process: After cooling from 20°C to -10°C at a rate of 10°C / min, The temperature was maintained at -10°C for 15 minutes. Temperature-raising step: The temperature was raised from -10°C to 130°C at a rate of 10°C / min.

[0178] The dimensional change rate (ΔL) is calculated by the following formula. The unit of the dimensional change rate (ΔL) is %. ΔL=ΔL(T1) ={(L1(T1)-L0) / L0}×100 L0 is the distance between the chucks when a load of 100 mN is applied at room temperature (23°C) before the start of measurement. L1(T1) is the distance between the chucks when the temperature T1 is any temperature within the range of 20°C to 120°C during the temperature rise process. Elongation: The dimensional change rate shows a positive value. Shrinkage: The dimensional change rate shows a negative value. From the dimensional change rates (ΔL) obtained within the range of 20°C to 120°C, the value of ΔL when the absolute value of ΔL was maximum was taken as the maximum dimensional change rate within the range of 20°C to 120°C.

[0179] [Molecular orientation evaluation] A Raman spectrum was obtained for a cross section of the stretched film obtained in the Examples or Comparative Examples using a Raman spectrometer (LabRAM HR800, manufactured by Horiba, Ltd.) as follows.

[0180] (Pretreatment) The stretched film was embedded in an embedding resin to prepare a block. Using a commercially available ultramicrotome capable of preparing frozen sections, the block was cut parallel to a plane including the thickness direction perpendicular to the main surface of the stretched film and the stretching direction of the stretched film (MD direction in the above Examples and Comparative Examples) in a low-temperature environment of -100°C. In this way, a cross section of the stretched film was obtained. Finishing was performed using a diamond knife.

[0181] (Raman measurement) The cut block was fixed on the stage of a Raman spectrometer so that the polarization direction of the laser was parallel to the stretching direction of the stretched film. A He-Ne laser with a wavelength of 633 nm was used as the excitation light source, and measurements were performed by irradiating a sample area of ​​approximately 1 μm diameter with the laser through a 100x objective lens. The laser output, irradiation time, and number of integrations were 1000 to 1600 cm. -1 The recommended conditions for the instrument were used so that the peaks could be sufficiently separated in the region and the peak intensities could be obtained stably. The measurements were performed in line mapping mode, in which the stage was moved in 1 μm steps in the direction perpendicular to the stretching direction, so that a spectrum of one or more points could be obtained for the stretched film. The stretching direction of the stretched film is defined as the X direction, the thickness direction as the Y direction, and the normal direction of the cross section as the Z direction. The incident direction of the laser is the Z direction. The polarization direction of the laser is the X direction. The mapping direction is the Y direction. In the Raman spectrum obtained by the above measurement, -1 The maximum scattering intensity of the peak near I 1130 value, and 1063 cm -1 The maximum scattering intensity of the peak near I 1063 From the value of I 1130 / I 1063 When two or more spectra were obtained, the arithmetic mean value of the above ratios obtained for each spectrum was calculated as the ratio I. 1130 / I 1063 It was decided.

[0182] [Puncture strength] The puncture strength of the stretched films obtained in the examples and comparative examples was measured in accordance with JIS Z1707:2019. The stretched films obtained in the examples and comparative examples were cut to obtain test pieces measuring 5 cm in width and 5 cm in length. A Tensilon universal material testing machine RCT-1250A (manufactured by AND Co.) was used as the measuring instrument. A semicircular needle with a diameter of 1.0 mm and a tip radius of 0.5 mm was pierced into the test piece at a test speed of 50 mm / min, and the maximum strength (N) until the needle penetrated the test piece was measured.

[0183] [Table 2] [Explanation of symbols]

[0184] 1. Stretched film 2. Laminate 60 Adhesive layer 61 First adhesive layer 62 Second adhesive layer 70 Polyolefin oriented substrate 80 Heat seal layer 81 First heat seal layer 82 Second heat seal layer

Claims

1. A film containing, as a main component, a high-density polyethylene (A) that satisfies at least one requirement selected from the group consisting of the following (1) and (2): (1) The high-density polyethylene (A) has a peak with a Full-Width at Quarter-Maximum (FWQM) value of less than 1.5 in a differential molecular weight distribution curve (horizontal axis: common logarithm (LogM) of molecular weight (M); vertical axis: value dW / d(LogM) obtained by differentiating cumulative concentration fraction (W) with common logarithm of molecular weight (M)) obtained by high-temperature gel permeation chromatography (GPC) measurement; (2) The 90th percentile value (LogM) of the molecular weight distribution in the differential molecular weight distribution curve of the high-density polyethylene (A) 90 ) and the 10th percentile value (LogM 10 ) and the difference (LogM 90 -LogM 10 ) is less than 1.

25.

2. The film according to claim 1, wherein the high-density polyethylene (A) satisfies at least one requirement selected from the group consisting of the following (3) and (4): (3) The peak of the high-density polyethylene (A) has a maximum dW / d(LogM) value of 0.80 or more in the differential molecular weight distribution curve; (4) The high-density polyethylene (A) has a density of 0.945 g / cm 3 Super 0.970g / cm 3 and / or a melting point of 125°C or higher and 140°C or lower.

3. The film according to claim 1, which is a monolayer film containing the high-density polyethylene (A) as a main component.

4. The film according to claim 1, which comprises two or more layers containing the high-density polyethylene (A) as a main component.

5. The film of claim 1 which is a substrate.

6. The film of claim 1 which is a printing substrate.

7. A stretched film obtained by stretching the film according to claim 1.

8. 8. The stretched film of claim 7, wherein the stretched film is a uniaxially stretched film.

9. The scattering intensity ratio I obtained by Raman spectroscopy in the cross section of the stretched film 1 / I 2 is 1.1 or more, the cross section is a plane parallel to a plane including a thickness direction perpendicular to a main surface of the stretched film and a stretching direction of the stretched film, I 1 is measured at 1100 cm in Raman spectroscopy. -1 1150cm or more -1 The maximum scattering intensity of the peak observed in the following region is I 2 is measured by Raman spectroscopy at 1050 cm -1 More than 1100cm -1 is the maximum scattering intensity of the peak observed in the region less than The stretched film according to claim 7.

10. 8. The stretched film according to claim 7, wherein a test piece of the stretched film is hung so that the film surface is parallel to the vertical direction and the stretching direction of the film is perpendicular to the vertical direction, and left in an environment of 120°C for 5 minutes, and the dimensional change rate in the stretching direction is measured in the range of -10% to 0%.

11. 8. The stretched film according to claim 7, wherein the stretched film has a maximum dimensional change rate of −15% or more and 15% or less in the stretching direction in a tensile mode of thermomechanical analysis (TMA) within a range of 20° C. to 120° C.

12. 8. The stretched film according to claim 7, wherein the entire polyethylene contained in the stretched film has a peak with an FWQM value of less than 1.8 in a differential molecular weight distribution curve obtained by high-temperature GPC measurement.

13. The stretched film according to claim 7, which is a substrate.

14. The stretched film according to claim 7, which is a printing substrate.

15. At least one film selected from the group consisting of the film according to any one of claims 1 to 6 and the stretched film according to any one of claims 7 to 14; a heat seal layer; A laminate comprising at least

16. The laminate according to claim 15, wherein the heat seal layer contains polyethylene as a main component, and the content of polyethylene in the entire laminate is 80 mass % or more.

17. A packaging container comprising the laminate according to claim 15.

18. The packaging container according to claim 17, which is a packaging bag.

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