Laminated film, packaging material, and package

Abstract

This laminated film comprises: a base material layer containing a high-density polyethylene; and a barrier resin layer containing one or more kinds of layers selected from the group consisting of a cured product layer of a mixture containing a polycarboxylic acid resin, a polyamine resin and a polyvalent metal compound, and a polyvinylidene chloride resin layer.

Description

Laminated film, packaging material and package

[0001] The present invention relates to a laminated film, a packaging material, and a package.

[0002] In the field of food packaging, films with gas barrier properties are being developed to ensure long-term storage of contents.

[0003] Patent Document 1 describes a gas barrier film laminate that aims to provide a film with gas barrier properties that is optimal as a packaging material, such as a film that is highly transparent, allowing the contents to be seen through and that can be used with a metal detector, has gas barrier properties under high temperature and high humidity conditions, can be used as a retort packaging material, and does not use any substances that are harmful to the environment. The gas barrier film laminate is characterized by laminating, in this order, on one or both sides of a substrate made of a plastic material, an anchor coat film layer whose main component is a resin with excellent acid resistance, and a gas barrier film layer made of a coating liquid in which poly(meth)acrylic acid has been added to a mixture of one or more types of metal alkoxide and its hydrolysate and a polymer having a hydroxyl group, and then heating and drying the laminate.

[0004] Japanese Patent Application Laid-Open No. 2003-191364

[0005] The present invention provides a laminated film with improved oxygen barrier properties.

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems. As a result, they have found that, in a laminate film including a substrate layer containing high-density polyethylene and a barrier resin layer, there is a correlation between the layers contained in the barrier resin layer and the oxygen barrier property of the laminate film. Based on the above findings, the present inventors have conducted further extensive research and found that the oxygen barrier property of the laminate film can be improved by including a specific layer in the barrier resin layer, thereby completing the present invention.

[0007] That is, according to the present invention, there are provided the following laminated film, packaging material, and packaging body.

[0008] [1] A laminate film comprising: a substrate layer containing high-density polyethylene; and a barrier resin layer containing one or more resins selected from the group consisting of a cured layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound, and a polyvinylidene chloride resin layer. [2] The laminate film according to [1], wherein the barrier resin layer contains a cured layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound. [3] The density of the substrate layer is 0.910 g / cm. ３The laminate film according to [1] or [2], wherein the base layer comprises a stretched film layer. [4] The laminate film according to any one of [1] to [3], wherein the base layer comprises a stretched film layer. [5] The laminate film according to any one of [1] to [4], wherein the content of the polyethylene polymer in the base layer relative to the total amount of the base layer is 75% by mass or more and 100% by mass or less. [6] The laminate film according to any one of [1] to [5], wherein the base layer comprises a core layer and a skin layer, the core layer, the skin layer, and the barrier resin layer being arranged in this order. [7] The laminate film according to [6], wherein the core layer comprises one or more types selected from the group consisting of high-density polyethylene and linear low-density polyethylene. [8] The laminate film according to [6] or [7], wherein the skin layer comprises one or more types selected from the group consisting of high-density polyethylene and linear low-density polyethylene. [9] The laminate film according to any one of [6] to [8], wherein the skin layer is in direct contact with at least one surface of the core layer.

[10] The laminate film according to any one of [1] to [9], wherein the thickness of the substrate layer is 5 μm or more and 100 μm or less.

[11] The laminate film according to any one of [1] to

[10] , wherein the ratio of the thickness of the substrate layer to the total thickness of the laminate film is 50% or more and less than 100%.

[12] The laminate film according to any one of [1] to

[11] , wherein the substrate layer and the barrier resin layer are in direct contact with each other.

[13] The laminate film according to any one of [1] to

[11] , wherein the barrier resin layer is provided on at least one surface of the substrate layer via an anchor coat layer.

[14] The thermal shrinkage rate of the substrate layer in the TD direction when heat-treated at 100°C for 15 minutes in accordance with JIS C2151:2019 is X ＴＤ When this is done, X ＴＤ

[15] The laminated film according to any one of [1] to

[13] , wherein the heat shrinkage rate in the TD direction of the base material layer when heat-treated at 100°C for 15 minutes in accordance with JIS C2151:2019 is X ＴＤ The heat shrinkage rate in the MD direction of the base material layer is X ＭＤ When this is done, X ＭＤ -X ＴＤ

[16] The laminate film according to any one of [1] to

[14] , wherein the average linear expansion coefficient in the machine direction of the base material layer is 5.0 × 10 or less, as measured in accordance with JIS K7197:1991 under conditions of a temperature rise rate of 5°C / min, a tensile load of 0.4 N, and a temperature of 20 to 100°C. －３

[17] The laminate film according to any one of [1] to

[15] , wherein the tensile modulus in the MD direction of the base material layer is T, measured using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a pulling speed of 5 mm / min in accordance with JIS K7127:1999. １ The tensile modulus of the base material layer in the TD direction is T ２ When this is done, T １ +T ２

[18] The laminate film according to any one of [1] to

[16] , wherein the tensile modulus in the TD direction of the substrate layer is measured in accordance with JIS K7127:1999 using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a pulling rate of 5 mm / min. ２ When this is done, T ２

[19] The laminate film according to any one of [1] to

[17] , wherein the tensile modulus in the MD direction of the substrate layer is measured in accordance with JIS K7127:1999 using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a pulling rate of 5 mm / min, and is T １ When this is done, T １

[20] The laminated film according to any one of [1] to

[18] , wherein the heat of fusion of the base material layer (ΔH ２ｎｄThe laminate film according to any one of [1] to

[19] , wherein the heat of fusion (ΔH ) is 158.0 J / g or more. (Method) When the following steps are sequentially performed using a differential scanning calorimeter (DSC): a first differential scanning calorimeter measurement (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining the temperature at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min, and a second differential scanning calorimeter measurement (2nd Run) consisting of a process of maintaining the temperature at -50°C for 5 minutes and increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, the heat of fusion (ΔH ) is determined from an endothermic peak observed in a range of 20°C to 160°C in DSC curve 2 obtained by the second differential scanning calorimeter measurement. ２ｎｄ

[21] Calculate the melting point (T ｍ２ The laminate film according to any one of [1] to

[20] , wherein the T is 125.0°C or higher. (Method) Using a differential scanning calorimeter (DSC), a first differential scanning calorimetry (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining the temperature at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min is performed in succession, and a second differential scanning calorimetry (2nd Run) consisting of a process of maintaining the temperature at -50°C for 5 minutes and a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min is performed, and the peak temperature of the maximum endothermic peak of DSC curve 2 obtained by the second differential scanning calorimetry is determined as T ｍ２

[22] The laminate film according to any one of [1] to

[21] , wherein the 180° peel strength between the laminate film and the LLDPE film, as measured by the following method, is greater than 1.8 N / 15 mm. (Method) An adhesive is applied to one side of a 50 μm-thick LLDPE film. The laminate film and the LLDPE film are then laminated together so that the surface of the laminate film facing the barrier resin layer is in contact with the adhesive-coated surface of the LLDPE film. The peel strength between the laminate film and the LLDPE film is then measured at 25°C and a tensile speed of 300 mm / min.

[23] The laminate film according to any one of [1] to

[22] , wherein the 180° peel strength between the laminate film and the LLDPE film, as measured by the following method, is greater than 0.2 N / 15 mm. (Method) An adhesive is applied to one side of a 50 μm-thick LLDPE film. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film on the barrier resin layer side is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the obtained multilayer film is subjected to a boiling treatment at 85°C for 30 minutes. Using the multilayer film after the boiling treatment, the peel strength between the laminated film and the LLDPE film is measured under conditions of 25°C and a pulling rate of 300 mm / min.

[24] The moisture permeability of the multilayer film calculated by the following method is 3.6 g / (m ２ The laminate film according to any one of [1] to

[23] , wherein the adhesive is less than 1000 times per day. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminate film and the LLDPE film are laminated together so that the surface of the laminate film on the barrier resin layer side and the adhesive-coated surface of the LLDPE film are in contact with each other, thereby obtaining a multilayer film. Next, the obtained multilayer film is folded back so that the LLDPE film faces inward, and the two sides are heat-sealed to form a bag. Thereafter, calcium chloride is placed as the content in the obtained bag. Next, the other side of the bag is heat-sealed to form a bag with a surface area of ​​0.01 m. ２The bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference.

[25] The moisture permeability of the multilayer film calculated by the following method is 3.7 g / (m ２ The laminate film according to any one of [1] to

[24] , wherein the adhesive is less than 1000 times per day. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminate film and the LLDPE film are laminated together so that the surface of the laminate film facing the barrier resin layer and the adhesive-coated surface of the LLDPE film are in contact with each other, thereby obtaining a multilayer film. Next, the obtained multilayer film is subjected to a boiling treatment at 85°C for 30 minutes. Using the multilayer film after the boiling treatment, it is folded back so that the LLDPE film faces inward, and the two sides are heat-sealed to form a bag. Thereafter, calcium chloride is placed as the content in the obtained bag. Next, the other side of the bag is heat-sealed to form a bag with a surface area of ​​0.01 m. ２ The bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference.

[26] The oxygen permeability of the multilayer film measured by the following method is 9900 mL / (m ２ The laminated film according to any one of [1] to

[25] , wherein the oxygen permeability (mL / (m )) or less is measured. (Method) An adhesive is applied to one side of an LLDPE film having a thickness of 50 μm. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film facing the barrier resin layer is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the oxygen permeability (mL / (m )) of the obtained multilayer film is measured. ２

[27] The oxygen permeability of the multilayer film measured by the following method is 8200 mL / (m ２The laminated film according to any one of [1] to

[26] , wherein the oxygen permeability (mL / (m)) of the multilayered film after the boiling treatment is 1 / 2000 of the barrier resin layer. (Method) An adhesive is applied to one side of an LLDPE film having a thickness of 50 μm. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film on the barrier resin layer side is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayered film. Next, the obtained multilayered film is subjected to a boiling treatment at 85° C. for 30 minutes. The oxygen permeability (mL / (m)) of the multilayered film after the boiling treatment is 1 / 2000 of the barrier resin layer. (Method) An adhesive is applied to one side of an LLDPE film having a thickness of 50 μm. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film on the barrier resin layer side is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayered film. Next, the obtained multilayered film is subjected to a boiling treatment at 85° C. for 30 minutes. ２ The compressive strength (MPa) of the laminate film is measured at 20°C and 90% RH in accordance with JIS K7126:2006.

[28] The laminate film according to any one of [1] to

[27] , which is a packaging film.

[29] A packaging material comprising the laminate film according to any one of [1] to

[28] .

[30] The packaging material according to

[29] , further comprising a heat seal layer on at least one outermost layer.

[31] The packaging material according to

[30] , comprising the base material layer, the barrier resin layer, and the heat seal layer, in this order.

[32] The packaging material according to

[30] or

[31] , wherein the heat seal layer contains polyethylene.

[33] The packaging material according to any one of

[29] to

[32] , further comprising a coating layer on at least one surface of the laminate film.

[34] A package comprising the packaging material according to any one of

[29] to

[33] , and an article placed inside the packaging material.

[0009] According to the present invention, a laminated film having improved oxygen barrier properties can be provided.

[0010] Fig. 1 is a cross-sectional view schematically showing an example of a laminate film according to the present embodiment. Fig. 2 is a cross-sectional view schematically showing an example of a laminate film according to the present embodiment. Fig. 3 is a cross-sectional view schematically showing an example of a laminate film according to the present embodiment.

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the drawings are schematic diagrams and do not correspond to actual dimensional proportions. In this specification, "A to B" indicating a numerical range means A or more and B or less unless otherwise specified.

[0012] In this embodiment, low density polyethylene (LDPE) has a density of 0.910 g / cm ３ 0.930g / cm or more ３ and medium density polyethylene (MDPE) refers to polyethylene having a density of less than 0.930 g / cm ３ 0.942g / cm or more ３ High density polyethylene (HDPE) refers to polyethylene having a density of less than 0.942 g / cm ３ Low-density polyethylene and medium-density polyethylene with little branching structure are referred to as linear low-density polyethylene (LLDPE).

[0013] 1 to 3 are cross-sectional views schematically illustrating an example of a laminate film according to the present embodiment. As shown in FIGS. 1 to 3, the laminate film 100 of the present embodiment includes a substrate layer 10 containing high-density polyethylene and a barrier resin layer 30. The barrier resin layer 30 includes one or more resins selected from the group consisting of a cured product layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound, and a polyvinylidene chloride resin layer.

[0014] The present inventors have found that in a laminate film 100 comprising a substrate layer 10 containing high-density polyethylene and a barrier resin layer 30, there is a correlation between the layers contained in the barrier resin layer 30 and the oxygen barrier property of the laminate film 100. As a result of further intensive studies based on the above findings, the present inventors have found that the oxygen barrier property of the laminate film 100 can be improved by including a predetermined layer in the barrier resin layer 30, and have completed the present invention.

[0015] The barrier resin layer 30 contains one or more resins selected from the group consisting of a cured layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound, and a polyvinylidene chloride resin layer, and preferably contains a cured layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound, thereby further improving the oxygen barrier properties of the laminate film 100 after boiling treatment.

[0016] The thickness of the barrier resin layer 30 is preferably 0.01 μm or more and 5.0 μm or less, more preferably 0.05 μm or more and 2.0 μm or less, and even more preferably 0.10 μm or more and 1.0 μm or less. By setting the thickness of the barrier resin layer 30 within the above range, the oxygen barrier property of the laminated film 100 can be further improved.

[0017] The layers included in the barrier resin layer 30 will be described in more detail below.

[0018] (Cured Layer of Mixture Containing Polycarboxylic Acid Resin, Polyamine Resin, and Polyvalent Metal Compound) The mixture of the present embodiment contains a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound.

[0019] The polycarboxylic acid resin has two or more carboxy groups in the molecule. Examples include polymers of α,β-unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, fumaric acid, crotonic acid, cinnamic acid, 3-hexenoic acid, and 3-hexenedioic acid, or copolymers thereof. The polycarboxylic acid resin may also be a copolymer of the above α,β-unsaturated carboxylic acid with an ester (e.g., ethyl ester) or an olefin (e.g., ethylene). From the viewpoint of further improving oxygen barrier properties, the polycarboxylic acid resin preferably contains one or more selected from the group consisting of polymers of acrylic acid, polymers of methacrylic acid, polymers of itaconic acid, polymers of fumaric acid, polymers of crotonic acid, polymers of cinnamic acid, and copolymers thereof. More preferably, the polycarboxylic acid resin contains one or more selected from the group consisting of polyacrylic acid, polymethacrylic acid, and copolymers of acrylic acid and methacrylic acid. Even more preferably, the polycarboxylic acid resin contains at least one selected from polyacrylic acid and polymethacrylic acid.

[0020] Here, in this embodiment, polyacrylic acid includes both a homopolymer of acrylic acid and a copolymer of acrylic acid and other monomers. When polyacrylic acid is a copolymer of acrylic acid and other monomers, the polyacrylic acid contains, for example, 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more of structural units derived from acrylic acid in 100% by mass of the polymer. Furthermore, in this embodiment, polymethacrylic acid includes both a homopolymer of methacrylic acid and a copolymer of methacrylic acid and other monomers. When polymethacrylic acid is a copolymer of methacrylic acid and other monomers, the polymethacrylic acid contains, for example, 90% by mass or more, preferably 95% by mass or more, and more preferably 99% by mass or more of structural units derived from methacrylic acid in 100% by mass of the polymer.

[0021] From the viewpoint of achieving an excellent balance between oxygen barrier properties and ease of handling, the molecular weight of the polycarboxylic acid resin is preferably 500 to 2,500,000, more preferably 5,000 to 2,000,000, even more preferably 10,000 to 1,500,000, still more preferably 100,000 to 1,200,000, even more preferably 300,000 to 1,100,000, still more preferably 500,000 to 1,000,000, and even more preferably 600,000 to 900,000. Here, in this embodiment, the molecular weight of the polycarboxylic acid resin is a weight average molecular weight in terms of polyethylene oxide, and can be measured using gel permeation chromatography (GPC).

[0022] The polycarboxylic acid resin may be at least partially neutralized with a volatile base. Neutralizing the polycarboxylic acid resin with a volatile base can prevent gelation when the polycarboxylic acid resin is mixed with a polyvalent metal compound or a polyamine resin. Therefore, in order to prevent gelation, it is preferable to partially or completely neutralize the carboxyl groups of the polycarboxylic acid resin with a volatile base. The neutralized product can be obtained by partially or completely neutralizing the carboxyl groups of the polycarboxylic acid resin with a volatile base, i.e., by partially or completely converting the carboxyl groups of the polycarboxylic acid resin into carboxylates. This prevents gelation when the polyamine resin or polyvalent metal compound is added. The partially neutralized product can be prepared by adding a volatile base to an aqueous solution of the polycarboxylic acid resin, and the desired degree of neutralization can be achieved by adjusting the ratio of the polycarboxylic acid resin to the volatile base. In this embodiment, the degree of neutralization of the polycarboxylic acid resin with a volatile base is preferably 50 to 500 equivalent %, more preferably 100 to 400 equivalent %, and even more preferably 200 to 300 equivalent %, from the viewpoint of sufficiently suppressing gelation caused by the neutralization reaction with the amino group of the polyamine resin.

[0023] Any water-soluble base can be used as the volatile base. Examples of the volatile base include ammonia, morpholine, alkylamines, tertiary amines such as 2-dimethylaminoethanol, N-methylmorpholine, ethylenediamine, and triethylamine, aqueous solutions of these, and mixtures of these. From the viewpoint of obtaining good oxygen barrier properties, the volatile base is preferably ammonia.

[0024] The polyamine resin is a compound having two or more amino groups in the main chain, side chain, or terminal, and is preferably a polymer. Examples include aliphatic polyamines such as polyallylamine, polyvinylamine, polyethyleneimine, and poly(trimethyleneimine); and polyamides having amino groups in the side chain, such as polylysine and polyarginine. Polyamines in which some of the amino groups have been modified may also be used. From the viewpoint of further improving oxygen barrier properties, the polyamine resin preferably contains one or more selected from the group consisting of polyallylamine, polyvinylamine, polyethyleneimine, and poly(trimethyleneimine), and more preferably contains polyethyleneimine.

[0025] From the viewpoint of achieving an excellent balance between oxygen barrier properties and ease of handling, the number average molecular weight of the polyamine resin is preferably 50 to 2,000,000, more preferably 100 to 1,000,000, even more preferably 1,500 to 500,000, still more preferably 1,500 to 100,000, even more preferably 1,500 to 50,000, still more preferably 3,500 to 20,000, still more preferably 5,000 to 15,000, and even more preferably 7,000 to 12,000. Here, in the present embodiment, the molecular weight of the polyamine resin can be measured using a boiling point elevation method or a viscosity method.

[0026] In the mixture of the present embodiment, the ratio (the number of moles of amino groups contained in the polyamine resin) / (the number of moles of -COO- groups contained in the polycarboxylic acid resin) is preferably 0.40 or more and 0.70 or less, more preferably 0.45 or more and 0.65 or less, and even more preferably 0.50 or more and 0.60 or less, from the viewpoint of further improving the oxygen barrier property.

[0027] The polyvalent metal compound contained in the mixture of this embodiment is, for example, a metal or metal compound belonging to Groups 2 to 13 of the periodic table. The polyvalent metal compound preferably contains one or more selected from the group consisting of divalent or higher valent metals such as magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and aluminum (Al), and oxides, hydroxides, halides, carbonates, phosphates, phosphites, hypophosphites, sulfates, and sulfites of these metals, more preferably one or two or more selected from the group consisting of magnesium oxide, calcium oxide, barium oxide, zinc oxide, magnesium hydroxide, calcium hydroxide, barium hydroxide, and zinc hydroxide, even more preferably one or two or more selected from the group consisting of zinc oxide and zinc hydroxide, and even more preferably zinc oxide.

[0028] In the mixture of this embodiment, the ratio (number of moles of polyvalent metal compound) / (number of moles of -COO- groups contained in the polycarboxylic acid resin) is preferably 0.20 or more and 0.80 or less, more preferably 0.30 or more and 0.70 or less, even more preferably 0.35 or more and 0.60 or less, and even more preferably 0.40 or more and 0.55 or less, from the viewpoint of further improving the oxygen barrier property. In the mixture of this embodiment, the ratio (number of moles of polyvalent metal compound) / (number of moles of amino groups contained in the polyamine resin) is preferably 0.50 or more and 1.00 or less, more preferably 0.60 or more and 0.95 or less, and even more preferably 0.70 or more and 0.90 or less, from the viewpoint of further improving the oxygen barrier property.

[0029] The mixture of this embodiment preferably further contains a polyphosphate compound or a salt thereof. This can further improve the oxygen barrier property. Specific examples of polyphosphate compounds include those having a condensation structure of two or more phosphoric acids in the molecular structure, such as diphosphate (pyrophosphate), triphosphate (tripolyphosphate), and polyphosphate compounds in which four or more phosphoric acids are condensed.

[0030] Specific examples of the salt in the salt of the polyphosphate compound include salts of monovalent metals such as sodium and potassium; and ammonium salts. From the viewpoint of oxygen barrier property, the salt of the polyphosphate compound is preferably an ammonium salt. Specific examples of the polyphosphate compound or its salt include at least one selected from the group consisting of oligomeric polyphosphates or salts thereof, such as oligomeric polyphosphate, oligomeric ammonium polyphosphate, oligomeric sodium polyphosphate, and oligomeric potassium polyphosphate; pyrophosphoric acid or salts thereof, such as pyrophosphoric acid, ammonium pyrophosphate, sodium pyrophosphate, and potassium pyrophosphate; tripolyphosphates or salts thereof, such as tripolyphosphate, ammonium tripolyphosphate, sodium tripolyphosphate, and potassium tripolyphosphate; and tetrapolyphosphates or salts thereof, such as tetrapolyphosphate, ammonium tetrapolyphosphate, sodium tetrapolyphosphate, and potassium tetrapolyphosphate. Among these, from the viewpoint of further improving oxygen barrier property, oligomeric polyphosphates or salts thereof are preferred, and ammonium oligomeric polyphosphate is more preferred. Herein, "oligomeric polyphosphate" refers to, for example, polyphosphates having a degree of polymerization of 5 or more and 100 or less.

[0031] In this embodiment, from the viewpoint of further improving the oxygen barrier property, the ratio (number of moles of P contained in the polyphosphate compound or its salt) / (number of moles of -COO- groups contained in the polycarboxylic acid resin) is preferably 0.005 or more and 0.20 or less, more preferably 0.007 or more and 0.15 or less, and even more preferably 0.010 or more and 0.10 or less. In a polyphosphate compound containing multiple P atoms in its chemical formula, the number of moles of P atoms is calculated by multiplying the number of moles of the polyphosphate compound by the number of P atoms contained in the chemical formula.

[0032] The mixture of this embodiment preferably further contains an ammonium carbonate salt. The ammonium carbonate salt is added to convert the polyvalent metal compound into an ammonium complex, thereby improving the solubility of the polyvalent metal compound and preparing a homogeneous solution containing the polyvalent metal compound. By including the ammonium carbonate salt in the mixture, the amount of the polyvalent metal compound dissolved can be increased, and as a result, the mixture containing the polyvalent metal compound can be made more homogeneous. Examples of the ammonium carbonate salt include ammonium carbonate and ammonium bicarbonate. Ammonium carbonate is preferred because it is easily volatilized and does not easily remain in the resulting cured product layer.

[0033] When the mixture further contains a carbonate-based ammonium salt, the ratio (molar number of carbonate-based ammonium salt) / (molar number of polyvalent metal compound) is preferably 0.05 to 10.0, more preferably 0.10 to 5.0, and even more preferably 0.50 to 2.0. By making the ratio equal to or greater than the lower limit, the solubility of the polyvalent metal compound can be further improved. On the other hand, by making the ratio equal to or less than the upper limit, the coatability of the mixture can be further improved.

[0034] From the viewpoint of improving oxygen barrier properties, the mixture of this embodiment preferably further contains a surfactant. The content of the surfactant is preferably 0.01% by mass or more and 3% by mass or less, and more preferably 0.05% by mass or more and 1% by mass or less, when the total solid content of the mixture (the total amount of components remaining as solids when the mixture is cured) is taken as 100% by mass. In this specification, the solid content of the mixture refers to the components remaining as solids when the mixture is cured.

[0035] Examples of surfactants include anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants. From the viewpoint of obtaining good coating properties, nonionic surfactants are preferred, polyoxyalkylene alkyl ethers are more preferred, and polyoxyethylene alkyl ethers are even more preferred.

[0036] Examples of nonionic surfactants include polyoxyalkylene alkyl aryl ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, sorbitan fatty acid esters, silicone surfactants, acetylene alcohol surfactants, and fluorine-containing surfactants.

[0037] Examples of polyoxyalkylene alkyl aryl ethers include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, and polyoxyethylene dodecylphenyl ether. Examples of polyoxyalkylene alkyl ethers include polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether. Examples of polyoxyalkylene fatty acid esters include polyoxyethylene oleate, polyoxyethylene laurate, and polyoxyethylene distearate. Examples of sorbitan fatty acid esters include sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate. Examples of silicone surfactants include dimethylpolysiloxane. Examples of acetylene alcohol surfactants include 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyne-3-ol, etc. Examples of fluorine-containing surfactants include fluorine alkyl esters, etc.

[0038] The mixture of this embodiment may further contain other components, such as crosslinkers, lubricants, slip agents, antiblocking agents, antistatic agents, antifogging agents, pigments, dyes, inorganic or organic fillers, etc. Examples of crosslinkers include epoxysilane compounds, carbodiimide compounds, and isocyanate compounds.

[0039] (Polyvinylidene chloride resin layer) The polyvinylidene chloride resin layer is a layer containing a polyvinylidene chloride resin as a main component. Here, containing a polyvinylidene chloride resin as a main component means that the polyvinylidene chloride resin layer contains 50% by mass or more of a polyvinylidene chloride resin. From the viewpoint of further improving oxygen barrier properties, the polyvinylidene chloride resin layer contains preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more of a polyvinylidene chloride resin.

[0040] The polyvinylidene chloride resin of the present embodiment is not particularly limited as long as it contains vinylidene chloride monomers as a constituent unit, and may be polyvinylidene chloride (PVDC) or a copolymer of vinylidene chloride and a monomer copolymerizable with vinylidene chloride.

[0041] An example of the copolymer is one having a vinylidene chloride content of 60% by mass or more and less than 100% by mass, and a content of a monomer copolymerizable with vinylidene chloride of more than 0% by mass and not more than 40% by mass. Examples of monomers copolymerizable with vinylidene chloride include (meth)acrylic acid esters such as alkyl esters or cycloalkyl esters having 1 to 18 carbon atoms of (meth)acrylic acid, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, cyclohexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate; and (meth)acrylic acid esters such as alkoxyalkyl esters having 2 to 18 carbon atoms of (meth)acrylic acid, such as methoxybutyl (meth)acrylate, methoxyethyl (meth)acrylate, and ethoxybutyl (meth)acrylate; (meth)acrylic acid, crotonic acid, itaconic acid, itaconic anhydride, maleic acid, maleic anhydride, fumaric acid, and thiophene. Examples of the monomer include one or more selected from ethylenic α,β-unsaturated carboxylic acids having a carboxyl group, such as acrylonitrile, unsaturated amide compounds, such as (meth)acrylamide and diacetone acrylamide; nitrile group-containing monomers, such as acrylonitrile and methacrylonitrile; acrylic acid or hydroxyalkyl esters of (meth)acrylic acid having 2 to 8 carbon atoms, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate; hydroxyl group-containing monomers, such as polyoxyethylene monoacrylate, polyoxyethylene monomethacrylate, N-methylol (meth)acrylamide, and allyl alcohol; and other polymerizable unsaturated monomers, such as styrene, α-methylstyrene, vinyl chloride, butadiene, vinyltoluene, vinyl acetate, alkyl itaconic acid esters, ethylene, propylene, and isobutylene.

[0042] The polyvinylidene chloride resin used in the polyvinylidene chloride resin layer can be produced by a conventionally known method, but various commercially available products can also be used. As a commercially available product, the Saran Resin series manufactured by Asahi Kasei Corporation can be preferably used.

[0043] The polyvinylidene chloride resin layer may contain a silane coupling agent. The silane coupling agent is not particularly limited, but examples thereof include halogen-containing silane coupling agents such as 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-chloropropyltrimethoxysilane, and 3-chloropropyltriethoxysilane; epoxy group-containing silane coupling agents such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane, 2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, and 3-glycidyloxypropyltriethoxysilane; 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane, and 3- Examples of such silane coupling agents include amino group-containing silane coupling agents such as [N-(2-aminoethyl)amino]propyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-[N-(2-aminoethyl)amino]propylmethyldimethoxysilane; mercapto group-containing silane coupling agents such as 2-mercaptoethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, and 3-mercaptopropyltriethoxysilane; vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; and (meth)acryloyl group-containing silane coupling agents such as 2-methacryloyloxyethyltrimethoxysilane, 2-methacryloyloxyethyltriethoxysilane, 2-acryloyloxyethyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-acryloyloxypropyltrimethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

[0044] From the viewpoint of improving the appearance of the resulting polyvinylidene chloride resin layer, the silane coupling agent preferably includes at least one of an epoxy group-containing silane coupling agent and an amino group-containing silane coupling agent, and examples thereof include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane, 2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethyltriethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 2-aminopropyltrimethoxysilane, 2-aminopropyltriethoxy ... It is more preferable that the silane compound contains one or more selected from the group consisting of silane, 3-aminopropyltriethoxysilane, 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane, 3-[N-(2-aminoethyl)amino]propyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, and 3-[N-(2-aminoethyl)amino]propylmethyldimethoxysilane, and it is even more preferable that the silane compound contains at least one selected from the group consisting of 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropyltriethoxysilane, 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane.

[0045] Furthermore, when the entire polyvinylidene chloride resin layer is taken as 100% by mass, the content of the silane coupling agent in the polyvinylidene chloride resin layer is preferably 0.5% by mass or more and 10% by mass or less, and more preferably 1.0% by mass or more and 5% by mass or less.

[0046] From the viewpoint of simplifying the manufacturing process of the laminated film 100, it is preferable that the substrate layer 10 and the barrier resin layer 30 are in direct contact with each other as shown in FIG.

[0047] (Anchor Coat Layer) From the viewpoint of ensuring good bonding between the substrate layer 10 and the barrier resin layer, as shown in FIG. 3 , the barrier resin layer 30 is preferably provided on at least one surface of the substrate layer 10 via an anchor coat layer 50. The anchor coat layer 50 contains, for example, an anchor coat agent. The anchor coat agent may include, for example, one or more agents selected from the group consisting of an isocyanate-based anchor coat agent, a urethane-based anchor coat agent, polyethyleneimine, an epoxy resin, a silane coupling agent, polyvinyl acetate, and an ethylene-vinyl acetate copolymer. Preferably, the anchor coat agent includes one or more agents selected from the group consisting of an isocyanate-based anchor coat agent and a urethane-based anchor coat agent, and more preferably, an isocyanate-based anchor coat agent. This allows good bonding between the substrate layer 10 and the barrier resin layer to be maintained even under high humidity conditions. Examples of isocyanate-based anchor coat agents include aqueous isocyanates. Commercially available anchor coat agents can be used as appropriate.

[0048] The content of the anchor coating agent in the anchor coat layer 50 relative to the entire anchor coat layer 50 is preferably 80% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less. By setting the content of the anchor coating agent in the anchor coat layer 50 relative to the entire anchor coat layer 50 within the above range, good bonding between the substrate layer 10 and the barrier resin layer 30 can be achieved.

[0049] The coating amount of the anchor coat layer 50 is preferably 0.01 g / m ２ 3g / m or more ２ or less, more preferably 0.05 g / m ２ 1g / m or more ２ More preferably, 0.05 g / m or less ２ 0.5g / m or more ２ By setting the coating amount of the anchor coat layer 50 within the above range, the bonding between the substrate layer 10 and the barrier resin layer 30 can be improved.

[0050] (Substrate Layer) The substrate layer 10 contains high-density polyethylene. The substrate layer 10 may contain other polyethylene polymers in addition to high-density polyethylene. The substrate layer 10 may further contain, for example, one or more selected from the group consisting of medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), or may further contain linear low-density polyethylene (LLDPE).

[0051] The content of the polyethylene polymer in the base layer 10 relative to the entire base layer 10 is preferably 75% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 85% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 98% by mass or more and 100% by mass or less. By setting the content of the polyethylene polymer in the base layer 10 relative to the entire base layer 10 to be equal to or greater than the above lower limit, the laminate film 100 can be well balanced in various performance characteristics such as thermal dimensional stability, film formability, heat resistance, mechanical properties, and rigidity. Furthermore, by setting the content of the polyethylene polymer in the base layer 10 relative to the entire base layer 10 to be equal to or greater than the above lower limit, the laminate film 100 can be improved in performance balance between processability and continuous productivity.

[0052] The content of high-density polyethylene in the base layer 10 relative to the entire base layer 10 is preferably 30% by mass or more and 100% by mass or less, more preferably 35% by mass or more and 95% by mass or less, even more preferably 40% by mass or more and 90% by mass or less, even more preferably 45% by mass or more and 85% by mass or less, and even more preferably 50% by mass or more and 80% by mass or less. By setting the content of high-density polyethylene in the base layer 10 relative to the entire base layer 10 within the above range, the laminate film 100 can achieve a good balance of various performance characteristics such as thermal dimensional stability, film formability, heat resistance, mechanical properties, and rigidity.

[0053] When the base layer 10 further contains linear low-density polyethylene, the content of linear low-density polyethylene in the base layer 10 relative to the entire base layer 10 is preferably more than 0% by mass and not more than 70% by mass, more preferably 10% by mass or more and not more than 60% by mass, and even more preferably 20% by mass or more and not more than 50% by mass. By setting the content of linear low-density polyethylene in the base layer 10 relative to the entire base layer 10 within the above range, the laminate film 100 can achieve a good balance of various performance properties such as thermal dimensional stability, film-formability, heat resistance, mechanical properties, and rigidity.

[0054] The density of the substrate layer 10, measured in accordance with JIS K 7112:1999, is preferably 0.910 g / cm ３ 0.970g / cm or more ３ or less, more preferably 0.920 g / cm ３ 0.965g / cm or more ３ More preferably, 0.930 g / cm or less ３ 0.960g / cm or more ３ More preferably, 0.942 g / cm ３ 0.955g / cm or more ３ By setting the density of the base material layer 10 to the above lower limit or more, it is possible to achieve a good balance between various performance characteristics of the laminate film 100, such as thermal dimensional stability, film-formability, heat resistance, mechanical properties, and rigidity. Furthermore, by setting the density of the base material layer 10 to the above upper limit or less, it is possible to improve the film-formability of the laminate film 100.

[0055] The base material layer 10 preferably includes a stretched film layer, more preferably a uniaxially stretched film layer or a biaxially stretched film layer, and even more preferably a biaxially stretched film layer, which allows the laminated film 100 to have a good balance of various properties such as thermal dimensional stability, film formability, heat resistance, barrier properties, mechanical properties, and rigidity.

[0056] The thickness of the substrate layer 10 is preferably 5 μm to 100 μm, more preferably 10 μm to 50 μm, and even more preferably 15 μm to 30 μm. By setting the thickness of the substrate layer 10 within the above range, the performance balance of the laminated film 100 can be improved, including thermal dimensional stability, film-forming properties, water vapor barrier properties, cost, mechanical properties, transparency, bag-forming properties, handleability, appearance, and light weight.

[0057] The ratio of the thickness of the base layer 10 to the total thickness of the laminate film 100 is preferably 50% or more and less than 100%, more preferably 60% or more and 99% or less, even more preferably 70% or more and 99% or less, even more preferably 80% or more and 99% or less, even more preferably 90% or more and 99% or less, and even more preferably 95% or more and 98% or less. By setting the ratio of the thickness of the base layer 10 to the total thickness of the laminate film 100 within the above range, the performance balance of the laminate film 100 can be improved, including thermal dimensional stability, film-formability, water vapor barrier property, cost, mechanical properties, transparency, bag-formability, handleability, appearance, and light weight.

[0058] 2, the substrate layer 10 preferably includes a plurality of layers. That is, the substrate layer 10 preferably includes a core layer 11 and a skin layer 13. More specifically, the substrate layer 10 preferably includes the core layer 11 and the skin layer 13, and is provided with the core layer 11, the skin layer 13, and the barrier resin layer 30 in this order.

[0059] The core layer 11 preferably contains a polyethylene polymer. The polyethylene polymer preferably contains one or more selected from the group consisting of high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), more preferably contains one or more selected from the group consisting of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), and even more preferably contains high-density polyethylene (HDPE). This allows the laminate film 100 to have a good balance of various properties such as thermal dimensional stability, film-formability, heat resistance, water vapor barrier properties, mechanical properties, and rigidity.

[0060] The content of the polyethylene polymer in the core layer 11 relative to the entire core layer 11 is preferably 75% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 85% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 98% by mass or more and 100% by mass or less. By setting the content of the polyethylene polymer in the core layer 11 relative to the entire core layer 11 to be equal to or greater than the above-mentioned lower limit, the laminate film 100 can be well balanced in various performances such as thermal dimensional stability, film formability, heat resistance, mechanical properties, and rigidity. Furthermore, by setting the content of the polyethylene polymer in the core layer 11 relative to the entire core layer 11 to be equal to or greater than the above-mentioned lower limit, the laminate film 100 can be improved in performance balance between processability and continuous productivity.

[0061] The skin layer 13 preferably contains a polyethylene polymer. The polyethylene polymer preferably contains one or more selected from the group consisting of high-density polyethylene (HDPE), medium-density polyethylene (MDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE), more preferably one or more selected from the group consisting of high-density polyethylene (HDPE) and linear low-density polyethylene (LLDPE), and even more preferably linear low-density polyethylene (LLDPE). This allows the laminate film 100 to have a good balance of various properties such as thermal dimensional stability, film-forming ability, heat resistance, water vapor barrier properties, mechanical properties, and rigidity.

[0062] When the core layer 11 contains high-density polyethylene (HDPE), the skin layer 13 preferably contains linear low-density polyethylene (LLDPE), which allows the laminate film 100 to have a good balance of various properties such as thermal dimensional stability, film-forming properties, heat resistance, water vapor barrier properties, mechanical properties, and rigidity.

[0063] The content of the polyethylene polymer in the skin layer 13 relative to the entire skin layer 13 is preferably 75% by mass or more and 100% by mass or less, more preferably 80% by mass or more and 100% by mass or less, even more preferably 85% by mass or more and 100% by mass or less, even more preferably 90% by mass or more and 100% by mass or less, even more preferably 95% by mass or more and 100% by mass or less, and even more preferably 98% by mass or more and 100% by mass or less. By setting the content of the polyethylene polymer in the skin layer 13 relative to the entire skin layer 13 to be equal to or greater than the above-mentioned lower limit, the laminate film 100 can be well balanced in various performance characteristics such as thermal dimensional stability, film formability, heat resistance, mechanical properties, and rigidity. Furthermore, by setting the content of the polyethylene polymer in the skin layer 13 relative to the entire skin layer 13 to be equal to or greater than the above-mentioned lower limit, the laminate film 100 can be improved in performance balance between processability and continuous productivity.

[0064] The skin layer 13 is preferably in direct contact with at least one surface of the core layer 11. This simplifies the manufacturing process of the laminated film 100.

[0065] The base layer 10 may contain various additives, such as a tackifier, a heat stabilizer, a weather stabilizer, an antioxidant, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, an antiblocking agent, an antistatic agent, an antifogging agent, a pigment, a dye, and an inorganic or organic filler, as needed, within a range that does not impair the object of this embodiment.

[0066] (Physical properties of laminated film) The thermal shrinkage rate of the base material layer 10 in the TD direction when heat-treated at 100°C for 15 minutes in accordance with JIS C2151:2019 was determined as X ＴＤ Heat shrinkage rate X ＴＤ is preferably less than 4.4%, more preferably 4.0% or less, even more preferably 3.5% or less, even more preferably 3.0% or less, even more preferably 2.5% or less, and even more preferably 2.0% or less. ＴＤ By setting the heat shrinkage rate X in the above range, the oxygen barrier property of the laminated film 100 can be further improved. ＴＤ By setting the heat shrinkage rate X in the above range, the performance balance between the thermal dimensional stability and the bag formability of the laminated film 100 can be improved. ＴＤThe lower limit of the heat shrinkage ratio X is not particularly limited, but may be, for example, 0% or more, 0.01% or more, 0.05% or more, or 0.1% or more. ＴＤ From the viewpoint of further improving the oxygen barrier properties of the laminated film 100, is preferably 0% or more and less than 4.4%, more preferably 0.01% or more and 4.0% or less, even more preferably 0.01% or more and 3.5% or less, even more preferably 0.01% or more and 3.0% or less, even more preferably 0.01% or more and 2.5% or less, and even more preferably 0.1% or more and 2.0% or less.

[0067] In accordance with JIS C2151:2019, the heat shrinkage rate of the base material layer 10 in the MD direction when heat-treated at 100°C for 15 minutes is X ＭＤ Heat shrinkage rate X ＭＤ is preferably 5.0% or less, more preferably 4.5% or less, even more preferably 4.0% or less, and even more preferably 3.5% or less. ＭＤ By setting the heat shrinkage rate X in the above range, the oxygen barrier property of the laminated film 100 can be further improved. ＭＤ By setting the heat shrinkage rate X in the above range, the performance balance between the thermal dimensional stability and the bag formability of the laminated film 100 can be improved. ＭＤ The lower limit of the heat shrinkage ratio X is not particularly limited, but may be, for example, 0% or more, 0.01% or more, 0.1% or more, 0.5% or more, or 0.8% or more. ＭＤ From the viewpoint of further improving the oxygen barrier properties of the laminated film 100, is preferably 0% or more and 5.0% or less, more preferably 0.01% or more and 4.5% or less, even more preferably 0.1% or more and 4.0% or less, and even more preferably 0.5% or more and 3.5% or less.

[0068] X ＭＤ -X ＴＤ is preferably more than -3.3% and less than 3.3%, more preferably -2.5% or more and 3.0% or less, even more preferably -1.0% or more and 2.8% or less, even more preferably 0.0% or more and 2.5% or less, and even more preferably 0.5% or more and 2.2% or less. ＭＤ -X ＴＤBy setting X in the above range, the oxygen barrier property of the laminated film 100 can be further improved. ＭＤ -X ＴＤ By setting the thickness within the above range, the performance balance between the thermal dimensional stability and bag formability of the laminated film 100 can be improved.

[0069] The thermal shrinkage rate X ＴＤ and X ＭＤ is calculated by the following method. First, a 10 cm x 10 cm test piece is cut out from the base material layer 10, and the test piece is heat-treated at 100°C for 15 minutes. Next, the test piece is cooled to room temperature, and the length of the test piece is measured. The length in the MD direction of the test piece after heat treatment is taken as MD [cm], and the heat shrinkage rate X in the MD direction is ＭＤ The length of the test piece in the TD direction after the heat treatment is defined as TD [cm], and the thermal shrinkage rate in the TD direction X ＴＤ [%] is calculated by 100 × (10 - TD) / 10. Each of the above measurements is carried out three times, and the average value of the obtained measurements is used.

[0070] The average linear expansion coefficient in the MD direction of the base material layer 10, measured in accordance with JIS K7197:1991 under conditions of a temperature rise rate of 5°C / min, a tensile load of 0.4 N, and a temperature of 20 to 100°C, is preferably 5.0 x 10 －３ / °C or less, more preferably 4.0 × 10 －３ / °C or less, more preferably 3.0 x 10 －３ / °C or less, more preferably 2.0 x 10 －３ / °C or less, more preferably 1.0 x 10 －３ / °C or less, more preferably 0.5 × 10 －３ / °C or less. By setting the average linear expansion coefficient in the MD direction of the base layer 10 within the above range, the oxygen barrier property of the laminated film 100 can be further improved. The lower limit of the average linear expansion coefficient in the MD direction of the base layer 10 is not particularly limited, but may be, for example, 0 / °C or more, and may be 0.01 × 10 －３ / °C or more, and may be 0.05 × 10 －３ / °C or more, and may be 0.1 × 10 －３ / °C or more, and may be 0.2 × 10 －３The average linear expansion coefficient in the MD direction of the base material layer 10 may be preferably 0 / °C or more and 5.0 × 10 －３ / °C or less, more preferably 0.01 × 10 －３ / ℃ or more 4.0 x 10 －３ / °C or less, more preferably 0.05 × 10 －３ / ℃ or more 3.0 x 10 －３ / °C or less, more preferably 0.1 × 10 －３ / ℃ or more 2.0 x 10 －３ / °C or less, more preferably 0.2 × 10 －３ / °C or more 1.0 x 10 －３ / °C or less, more preferably 0.2 × 10 －３ / °C or more 0.5 x 10 －３ / °C or less.

[0071] The average linear expansion coefficient in the MD direction of the base material layer 10 is calculated by the following method. First, a test piece is cut out from the base material layer so that the test piece width is 4 mm and the initial chuck distance is 8 mm. Next, using a thermomechanical analyzer, thermomechanical analysis of the test piece is performed in accordance with JIS K7197:1991 under conditions of a heating rate of 5°C / min, a tensile load of 0.4 N, and a temperature of 20 to 100°C, and the average linear expansion coefficient in the MD direction of the base material layer is calculated.

[0072] The tensile modulus of elasticity in the MD direction of the base material layer 10 measured using a tensile tester in accordance with JIS K7127:1999 under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min is defined as T １ The tensile modulus of elasticity in the TD direction of the base material layer 10 is T ２ Let's say. T １ +T ２ is preferably 1000 MPa or more and 9000 MPa or less, more preferably 1500 MPa or more and 8000 MPa or less, and even more preferably 2000 MPa or more and 7000 MPa or less. １ +T ２ By setting the content of the polymer in the above range, the oxygen barrier property of the laminated film 100 can be further improved.

[0073] Tensile modulus T of the base material layer 10 in the MD direction １is preferably 490 MPa or more and 4000 MPa or less, more preferably 600 MPa or more and 3500 MPa or less, and even more preferably 700 MPa or more and 3000 MPa or less. １ By setting the content of the polymer in the above range, the oxygen barrier property of the laminated film 100 can be further improved.

[0074] The tensile modulus T of the base layer 10 in the TD direction ２ is preferably 520 MPa or more and 5000 MPa or less, more preferably 600 MPa or more and 4500 MPa or less, and even more preferably 700 MPa or more and 4000 MPa or less. ２ By setting the content of the polymer in the above range, the oxygen barrier property of the laminated film 100 can be further improved.

[0075] The tensile modulus T of the base material layer 10 in the MD direction is １ , and the tensile modulus T of the base material layer 10 in the TD direction ２ First, a test piece of 15 mm x 15 cm is cut out from the base layer 10. Then, the tensile modulus T of the test piece in the MD direction is measured in accordance with JIS K7127:1999 under the conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min. １ and tensile modulus in the TD direction T ２ are measured respectively.

[0076] The heat of fusion of the base layer 10 (ΔH ２ｎｄ ) is preferably 158.0 J / g or more and 250.0 J / g or less, more preferably 165.0 J / g or more and 245.0 J / g or less, even more preferably 170.0 J / g or more and 240.0 J / g or less, even more preferably 175.0 J / g or more and 235.0 J / g or less, and even more preferably 180.0 J / g or more and 230.0 J / g or less. ２ｎｄ ) in the above range, the oxygen barrier properties of the laminated film 100 can be further improved.

[0077] The melting point (T ｍ２The melting point (T ｍ２ ) in the above range, the oxygen barrier properties of the laminated film 100 can be further improved.

[0078] The heat of fusion of the base material layer 10 (ΔH ２ｎｄ ) and melting point (T ｍ２ ) can be obtained by the following method. Using a differential scanning calorimeter (DSC), a first differential scanning calorimetric measurement (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining the temperature at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min is carried out in a nitrogen atmosphere, followed by a second differential scanning calorimetric measurement (2nd Run) consisting of a process of maintaining the temperature at -50°C for 5 minutes and a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min. The peak temperature of the maximum endothermic peak of DSC curve 2 obtained by the 2nd Run is taken as T ｍ２ In the DSC curve 2 obtained by the second run, the heat of fusion ΔH is calculated from the endothermic peak observed in the range of 20°C to 160°C. ２ｎｄ In the DSC curve 2 obtained by the second run, when multiple endothermic peaks are observed in the range of 20°C to 160°C, the total value of the heat of fusion of the multiple endothermic peaks is calculated as the heat of fusion ΔH ２ｎｄ [J / g].

[0079] The 180° peel strength between the laminate film 100 and the LLDPE film is preferably greater than 1.8 N / 15 mm, more preferably 2.0 N / 15 mm or greater, and even more preferably 2.2 N / 15 mm or greater. By setting the 180° peel strength between the laminate film 100 and the LLDPE film within the above range, the bonding between the laminate film 100 and other layers (e.g., the LLDPE film) provided on the laminate film 100 can be improved, and the oxygen barrier properties of the multilayer film including the laminate film 100 can be further improved. The upper limit of the 180° peel strength between the laminate film 100 and the LLDPE film is not particularly limited, but may be, for example, 10.0 N / 15 mm or less, 7.5 N / 15 mm or less, or 5.0 N / 15 mm or less.

[0080] The 90° peel strength between the laminate film 100 and the LLDPE film is preferably greater than 1.5 N / 15 mm, more preferably 1.7 N / 15 mm or greater, and even more preferably 1.9 N / 15 mm or greater. By setting the 90° peel strength between the laminate film 100 and the LLDPE film within the above range, the bonding between the laminate film 100 and other layers (e.g., the LLDPE film) provided on the laminate film 100 can be improved, and the oxygen barrier properties of the multilayer film including the laminate film 100 can be further improved. The upper limit of the 90° peel strength between the laminate film 100 and the LLDPE film is not particularly limited, but may be, for example, 10.0 N / 15 mm or less, 7.5 N / 15 mm or less, or 5.0 N / 15 mm or less.

[0081] In this embodiment, the 180° peel strength and 90° peel strength between the laminate film 100 and the LLDPE film are measured by the following method. An adhesive is applied to one side of a 50 μm-thick LLDPE film. The laminate film 100 and the LLDPE film are then laminated together so that the surface of the laminate film 100 facing the barrier resin layer 30 comes into contact with the adhesive-coated surface of the LLDPE film. The 180° peel strength and 90° peel strength between the laminate film 100 and the LLDPE film are then measured at 25°C and a pulling rate of 300 mm / min.

[0082] The 180° peel strength between the laminate film 100 and the LLDPE film after boiling is preferably greater than 0.2 N / 15 mm, more preferably 0.6 N / 15 mm or greater, and even more preferably 1.2 N / 15 mm or greater. By ensuring that the 180° peel strength between the laminate film 100 and the LLDPE film after boiling is within the above range, the bonding between the laminate film 100 and other layers (e.g., the LLDPE film) provided on the laminate film 100 can be improved, and the oxygen barrier properties of the multilayer film including the laminate film 100 can be further improved. The upper limit of the 180° peel strength between the laminate film 100 and the LLDPE film after boiling is not particularly limited, but may be, for example, 10.0 N / 15 mm or less, 7.5 N / 15 mm or less, or 5.0 N / 15 mm or less.

[0083] The 90° peel strength between the laminate film 100 and the LLDPE film after boiling is preferably greater than 0.2 N / 15 mm, more preferably greater than 1.1 N / 15 mm, and even more preferably 1.5 N / 15 mm or greater. By ensuring that the 90° peel strength between the laminate film 100 and the LLDPE film after boiling is within the above range, the bonding between the laminate film 100 and other layers (e.g., the LLDPE film) provided on the laminate film 100 can be improved, and the oxygen barrier properties of the multilayer film including the laminate film 100 can be further improved. The upper limit of the 90° peel strength between the laminate film 100 and the LLDPE film after boiling is not particularly limited, but may be, for example, 10.0 N / 15 mm or less, 7.5 N / 15 mm or less, or 5.0 N / 15 mm or less.

[0084] In this embodiment, the 180° peel strength and 90° peel strength between the laminate film 100 and the LLDPE film after boiling treatment are measured by the following method. An adhesive is applied to one side of a 50 μm-thick LLDPE film. Next, the laminate film 100 and the LLDPE film are laminated together so that the surface of the laminate film 100 facing the barrier resin layer 30 contacts the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. The obtained multilayer film is then boiled at 85°C for 30 minutes. Using the multilayer film after boiling treatment, the 180° peel strength and 90° peel strength between the laminate film 100 and the LLDPE film are measured under conditions of 25°C and a tensile speed of 300 mm / min.

[0085] The moisture permeability of the multilayer film described below is preferably 3.6 g / (m ２ ·day), more preferably less than 3.4 g / (m ２ ·day), more preferably less than 3.2 g / (m ２ By setting the moisture permeability of the multilayer film within the above range, the water vapor barrier properties of the multilayer film including the laminated film 100 can be improved. The lower limit of the moisture permeability of the multilayer film is not particularly limited, but is, for example, 0.001 g / (m ２ · day) or more, and ２ · day) or more, and ２ ・day) or more.

[0086] The oxygen permeability of the multilayer film described below is preferably 9900 mL / (m ２ ·day·MPa) or less, more preferably 8000 mL / (m ２ ·day·MPa) or less, more preferably 6000 mL / (m ２ ·day·MPa) or less, more preferably 4000 mL / (m ２ ·day·MPa) or less, more preferably 2000 mL / (m ２ ·day·MPa) or less, more preferably 1500 mL / (m ２By setting the oxygen permeability of the multilayer film in the above range, the oxygen barrier properties of the multilayer film including the laminated film 100 can be improved. The lower limit of the oxygen permeability of the multilayer film is not particularly limited, but is, for example, 0.01 mL / (m ２ ·day·MPa) or more, and ２ ·day·MPa) or more, and ２ ·day·MPa) or more.

[0087] In this embodiment, the moisture permeability and oxygen permeability of the multilayer film are measured by the following method. An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminated film 100 and the LLDPE film are laminated together so that the surface of the laminated film 100 facing the barrier resin layer 30 is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the obtained multilayer film is folded back so that the LLDPE film faces inward, and the two sides are heat-sealed to form a bag. Thereafter, calcium chloride is placed as the content in the obtained bag. Next, the other side of the bag is heat-sealed to form a bag with a surface area of ​​0.01 m. ２ The bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of the calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference. The oxygen permeability (mL / (m ２ The thermal expansion coefficient (Tc) is measured in accordance with JIS K7126:2006 under conditions of 20°C and 90% RH.

[0088] The moisture permeability of the multilayer film after the boiling treatment described below is preferably 3.7 g / (m ２ ·day), more preferably less than 3.6 g / (m ２ ·day) or less, more preferably 3.5 g / (m ２ By setting the moisture permeability of the multilayer film after boiling treatment to the above range, the water vapor barrier property of the multilayer film including the laminate film 100 after boiling treatment can be improved. The lower limit of the moisture permeability of the multilayer film after boiling treatment is not particularly limited, but is, for example, 0.001 g / (m２ · day) or more, and ２ · day) or more, and ２ ・day) or more.

[0089] The oxygen permeability of the multilayer film after the boiling treatment described below is preferably 8200 mL / (m ２ ·day·MPa) or less, more preferably 6000 mL / (m ２ ·day·MPa) or less, more preferably 4000 mL / (m ２ ·day·MPa) or less, more preferably 2000 mL / (m ２ ·day·MPa) or less, more preferably 1500 mL / (m ２ By setting the oxygen permeability of the multilayer film after the boiling treatment in the above range, the oxygen barrier property of the multilayer film including the laminate film 100 after the boiling treatment can be improved. The lower limit of the oxygen permeability of the multilayer film after the boiling treatment is not particularly limited, but it can be, for example, 0.01 mL / (m ２ ·day·MPa) or more, and ２ ·day·MPa) or more, and ２ ·day·MPa) or more.

[0090] In this embodiment, the moisture permeability and oxygen permeability of the multilayer film after boiling treatment are measured by the following method. An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminate film 100 and the LLDPE film are laminated so that the surface of the laminate film 100 facing the barrier resin layer 30 is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the obtained multilayer film is boiled at 85°C for 30 minutes. Using the boiled multilayer film, the LLDPE film is folded back so that the inner surface is the LLDPE film, and the two sides are heat-sealed to form a bag. Thereafter, calcium chloride is placed in the obtained bag as the content. Next, the other side of the bag is heat-sealed to form a bag with a surface area of ​​0.01 m. ２The bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of the calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference. The oxygen permeability (mL / (m ２ The thermal expansion coefficient (Tc) is measured in accordance with JIS K7126:2006 under conditions of 20°C and 90% RH.

[0091] (Method for Producing Laminated Film) The laminated film 100 can be obtained, for example, by the following method. First, a resin composition containing a polyethylene polymer is extruded into a film, followed by stretching to obtain the substrate layer 10. When the substrate layer 10 includes multiple layers, the multiple layers are laminated together and then stretched. The molding apparatus and molding conditions are not particularly limited, and conventionally known molding apparatus and molding conditions can be employed. Examples of molding apparatus that can be used include a T-die extruder, a multi-layer T-die extruder, an inflation molding machine, and a multi-layer inflation molding machine. The stretching conditions can be those used for producing known polyethylene films. For example, in the sequential biaxial stretching method, the MD stretching temperature is preferably in the range of 100°C to 145°C, more preferably 110°C to 140°C, and even more preferably 120°C to 135°C, and the TD stretching temperature is preferably in the range of 110°C to 190°C, more preferably 120°C to 170°C. The stretching ratio in the MD direction may be set to a range of 4.5 to 7 times, and the stretching ratio in the TD direction may be set to a range of 9 to 11 times. Specifically, the stretching temperature must be set at three stages: preheating temperature (temperature at which the raw film is heated before stretching), stretching temperature (temperature during stretching), and heat setting temperature (temperature during heat setting (annealing) after stretching). Temperatures from preheating to heat setting can be set within the above ranges. That is, temperatures can be set to the same level as those for stretching and heat setting from the preheating stage onward.

[0092] Next, if necessary, an anchor coat layer 50 is formed on the substrate layer 10. The method for forming the anchor coat layer 50 is not particularly limited, and examples thereof include a method in which an anchor coating agent is applied to the substrate layer 10 and then dried. The method for applying the anchor coating agent is not particularly limited, and examples thereof include a method in which the anchor coating agent is applied using a known coating machine such as an air knife coater, kiss roll coater, metaling bar coater, gravure roll coater, reverse roll coater, dip coater, or die coater.

[0093] Next, the barrier resin layer 30 is formed on the substrate layer 10 or the anchor coat layer 50. The method for forming the barrier resin layer 30 is not particularly limited, but for example, the barrier resin layer 30 can be formed by applying a composition for the barrier resin layer onto the substrate layer 10 or the anchor coat layer 50 and then heating it.

[0094] (Uses of Laminate Film / Packaging Material / Packaging Body) Specifically, the laminate film 100 of this embodiment can be suitably used as a packaging film. The laminate film 100 of this embodiment can also be suitably used as a packaging material. That is, the packaging material of this embodiment includes the laminate film 100. When making a packaging material, the packaging material may be made using only the laminate film 100 of this embodiment, or another layer may be laminated on at least one surface of the laminate film 100 to make a packaging material. The other layer preferably includes one or more layers selected from the group consisting of a coating layer, a substrate layer, and an inorganic layer, and more preferably includes a coating layer. From the viewpoint of ease of recycling, the other layer is preferably formed of a polyethylene-based resin. When making a packaging material including the laminate film 100 of this embodiment, it is preferable to further include a heat-seal layer on at least one outermost layer of the packaging material, and more preferably to include the substrate layer 10, the barrier resin layer 30, and the heat-seal layer in this order. From the viewpoint of ease of recycling, the heat-seal layer preferably includes polyethylene. Furthermore, the packaging material of this embodiment can be suitably used for packaging. The packaging is used, for example, for packaging an item. Specifically, the packaging of this embodiment includes the packaging material of this embodiment and an item inside the packaging. In particular, the packaging of this embodiment can be suitably used as a food package and is used for packaging food. Specifically, the packaging of this embodiment includes the packaging material of this embodiment and food inside the packaging. Foods packaged in the food package are not particularly limited, but examples include baked goods, rice crackers, snacks, sprinkles, grain powder, etc. Depending on the application, only a portion of the package may be made of the packaging material of this embodiment, or substantially the entire package may be made of the packaging material of this embodiment.

[0095] The content of the ethylene polymer in the packaging material of this embodiment is preferably 50% by mass or more and less than 100% by mass, more preferably 70% by mass or more and less than 100% by mass, even more preferably 80% by mass or more and 99.9% by mass or less, still more preferably 90% by mass or more and 99.9% by mass or less, still more preferably 95% by mass or more and 99.5% by mass or less, and still more preferably 99.0% by mass or more and 99.5% by mass or less, when the entire packaging material is taken as 100% by mass. As a result, the packaging material is composed of almost a single material (monomaterial), which reduces the work of separating the materials that compose the packaging material and improves the recyclability of the packaging material.

[0096] The polyethylene content in the packaging material of this embodiment, when the entire packaging material is taken as 100% by mass, is preferably 50% by mass or more and less than 100% by mass, more preferably 70% by mass or more and less than 100% by mass, even more preferably 80% by mass or more and 99.9% by mass or less, still more preferably 90% by mass or more and 99.9% by mass or less, even more preferably 95% by mass or more and 99.8% by mass or less, and still more preferably 99.0% by mass or more and 99.8% by mass or less. This means that the packaging material is composed of almost a single material (monomaterial), which reduces the work of separating the materials that make up the packaging material and improves the recyclability of the packaging material.

[0097] There are no particular limitations on the method for producing a package from the laminate film 100 or the packaging material, and any method known in the field of packaging materials / packages, such as heat sealing or fusing, can be used as appropriate.

[0098] The laminated film 100 according to this embodiment is preferably used for packaging that requires good barrier properties. The form of the packaging can be, for example, a two-sided bag or a standing pouch (pouch packaging).

[0099] When a package (such as a food packaging bag) is constructed using the laminate film 100 of this embodiment or a packaging material, it is preferable that the corona-treated surface is the inner surface and the non-corona-treated surface is the outer surface. Furthermore, as described above, when another layer is laminated on the laminate film 100, it is preferable that the layer be laminated on the corona-treated surface. In other words, when a laminate using the laminate film 100 of this embodiment is used for a package (such as a food packaging bag), it is preferable that the laminate film 100 of this embodiment be the outermost layer of the package.

[0100] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0101] The present embodiment will be described in detail below with reference to examples and comparative examples, but the present embodiment is not limited to the descriptions of these examples.

[0102] 1. Raw Materials The raw materials used to prepare the base layer are as follows: LLDPE1: Linear low-density polyethylene (density: 0.928 g / cm ３ , MFR: 1.9 g / 10 min, melting point: 126 ° C.) LLDPE2: Linear low-density polyethylene (density: 0.937 g / cm ３ , MFR: 1.8 g / 10 min, melting point: 127 ° C) HDPE1: high-density polyethylene (density: 0.958 g / cm ３ , MFR: 1.0 g / 10 min, melting point: 133 ° C.) HDPE2: high-density polyethylene (density: 0.949 g / cm ３, MFR: 1.1 g / 10 min, melting point: 130°C). The density was measured in accordance with JIS K 7112:1999. The MFR was measured in accordance with JIS K 7210:1999 under conditions of 190°C and a load of 2160 g. The melting point was measured using a differential scanning calorimeter (DSC). Specifically, using a differential scanning calorimeter (product name: Q200DSC, manufactured by TA Instruments), a first differential scanning calorimeter measurement consisting of a process of increasing the temperature from -50°C to 230°C at a heating rate of 10°C / min and a process of decreasing the temperature from 230°C to -50°C at a heating rate of 10°C / min was performed in a nitrogen gas flow. A second differential scanning calorimeter measurement consisting of a process of increasing the temperature from -50°C to 230°C at a heating rate of 10°C / min was also performed. The peak temperature of the maximum endothermic peak in the second DSC curve was taken as the melting point (°C).

[0103] 2. Preparation of Substrate Layer Skin layer 1, core layer, and skin layer 2 were each extrusion-molded with the composition and layer configuration shown in Table 1. Stretching treatment was then carried out under the conditions shown in Table 1. Next, corona treatment was carried out on the surface on the skin layer 1 side to produce MDOPE, HDBOPE1, and HDBOPE2, respectively. The thickness of each film was 25 μm. The extrusion and stretching conditions were as follows: Extruder: 60 mmφ multilayer T-die extruder (screw: L / D = 27, manufactured by Screw Seiki Co., Ltd.) Extrusion set temperature: 230 to 250°C, Processing speed: 15 m / min (take-up speed). Note that the notation "A / B / C" for the stretching temperature in Table 1 means "preheating temperature (temperature for heating the raw film before stretching) / stretching temperature (temperature during stretching) / heat setting temperature (temperature during heat setting (annealing) after stretching)." The relaxation rate refers to the maximum stretching width in the device settings divided by the tenter outlet width.

[0104] 3. Evaluation of the base layer (1) Heat shrinkage The heat shrinkage of the base layer in the MD and TD directions when heated at 100 ° C for 15 minutes was measured in accordance with JIS C2151:2019. First, a 10 cm x 10 cm test piece was cut out from the base layer and heated at 100 ° C for 15 minutes. At this time, the test piece was heated by hanging it without applying force in a hot air circulation thermostatic oven (manufactured by ADVANTEC, product name: DRM620DE). Next, after cooling the test piece to room temperature, the length of the test piece was measured. The length of the test piece in the MD direction after heat treatment was defined as MD [cm], and the heat shrinkage in the MD direction X ＭＤ The length of the test piece in the TD direction after the heat treatment was taken as TD [cm], and the thermal shrinkage rate in the TD direction X ＴＤ [%] was calculated by 100 × (10 − TD) / 10. Each of the above measurements was carried out three times, and the average value of the obtained measurements was used.

[0105] (2) Thermomechanical Analysis First, a test piece was cut out from the substrate layer so that the width was 4 mm and the initial chuck distance was 8 mm. Next, using a thermomechanical analyzer TMA Q400 (manufactured by TA Instruments), thermomechanical analysis of the test piece was performed in accordance with JIS K7197:1991 under conditions of a heating rate of 5°C / min, a tensile load of 0.4 N, and a temperature of 20 to 100°C, and the average linear expansion coefficient in the MD direction of the substrate layer was calculated.

[0106] (3) Tensile Modulus First, a test piece of 15 mm x 15 cm was cut out from the substrate layer. Then, the tensile modulus T of the test piece in the MD direction was measured using a tensile tester manufactured by Orientec Co., Ltd., in accordance with JIS K7127:1999 under the conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min. １ and tensile modulus in the TD direction T ２ were measured respectively.

[0107] (4) Differential Scanning Calorimetry (DSC Measurement) Using a differential scanning calorimeter (manufactured by TA Instruments, product name: Q200DSC), a first differential scanning calorimetry (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min was performed in a nitrogen atmosphere. A second differential scanning calorimetry (2nd Run) consisting of a process of maintaining at -50°C for 5 minutes and a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min was performed successively. The peak temperature of the maximum endothermic peak of the DSC curve 1 obtained by the 1st Run was designated as T ｍ１ In the DSC curve 1 obtained in the first run, the heat of fusion ΔH was calculated from the endothermic peak observed in the range of 20°C to 160°C. １ｓｔ In the DSC curve 1 obtained in the first run, when multiple endothermic peaks were observed in the range of 20°C to 160°C, the total value of the heat of fusion of the multiple endothermic peaks was calculated as the heat of fusion ΔH １ｓｔ The peak temperature of the maximum endothermic peak of the DSC curve 2 obtained by the 2nd run was taken as T ｍ２ In the DSC curve 2 obtained by the second run, the heat of fusion ΔH was calculated from the endothermic peak observed in the range of 20°C to 160°C. ２ｎｄ In the DSC curve 2 obtained by the second run, when multiple endothermic peaks were observed in the range of 20°C to 160°C, the total value of the heat of fusion of the multiple endothermic peaks was calculated as the heat of fusion ΔH ２ｎｄ The mass was expressed in [J / g].

[0108] The evaluation results of the substrate layer are shown in Table 1.

[0109]

[0110] 4. Preparation of Laminated Films (Examples 1 to 6 and Comparative Examples 1 to 3) For Examples 1 to 6 and Comparative Examples 1 to 3, laminated films were prepared by forming a barrier resin layer on the corona-treated surface of the substrate layer under the conditions shown in Table 2. In none of the Examples and Comparative Examples was curling or film cracking of the barrier resin layer observed.

[0111] The methods A to C for forming the barrier resin layer are as follows.

[0112] (Method A) Polyacrylic acid (manufactured by Toagosei Co., Ltd., trade name: AC-10H, weight average molecular weight: 800,000), 10% by weight aqueous ammonia (manufactured by Wako Pure Chemical Industries, Ltd.), and purified water were mixed so that the ammonia concentration was 250 equivalent% relative to the carboxyl groups of the polyacrylic acid, to obtain an aqueous ammonium polyacrylate solution with a concentration of 7.29% by weight. Next, zinc oxide (manufactured by Kanto Chemical Co., Ltd.) and ammonium carbonate were added to the obtained aqueous ammonium polyacrylate solution, mixed, and stirred to obtain a mixed solution (1-A). Here, the amount of zinc oxide added was an amount such that the ratio (number of moles of zinc oxide in coating material A) / (number of moles of -COO- groups contained in polyacrylic acid in coating material A) was 0.475. Furthermore, the amount of ammonium carbonate added was an amount such that the ratio (number of moles of ammonium carbonate in coating material A) / (number of moles of zinc oxide in coating material A) was 1.5. Next, polyethyleneimine (manufactured by Nippon Shokubai Co., Ltd., trade name: SP-200, number average molecular weight: 10,000) was added to purified water to obtain a 10% by mass polyethyleneimine aqueous solution. Next, low-polymerized ammonium polyphosphate (manufactured by Amada Co., Ltd., product number: Water-soluble ammonium polyphosphate flame retardant NNA20, P ２ O ５Purified water was added to the mixture (1-A), the polyethyleneimine aqueous solution, and the low-polymerized ammonium polyphosphate aqueous solution as a phosphorus introduction source, and the mixture (1-A), the polyethyleneimine aqueous solution, and the low-polymerized ammonium polyphosphate aqueous solution as a phosphorus introduction source were mixed in a ratio of (the number of moles of amino groups contained in polyethyleneimine in coating material A) / (the number of moles of -COO- groups contained in polyacrylic acid in coating material A) 0.55, and (the number of moles of P contained in polyphosphate compound or its salt in coating material A) / (the number of moles of -COO- groups contained in polyacrylic acid in coating material A) 0.025 to obtain a mixture (2-A). Furthermore, purified water was added so that the solids concentration of the mixture (2-A) was 1.5% by mass, and the mixture was stirred until a uniform solution was obtained. A surfactant (polyoxyethylene lauryl ether, manufactured by Kao Corporation, trade name: Emulgen 120) was mixed so that the solids content of the mixture (2-A) was 0.3% by mass, and a coating material A was prepared. Coating material A was coated onto the substrate layer using a Mayer bar and heated in an oven at 70°C for 60 seconds to form a barrier resin layer with a thickness of 300 nm.

[0113] (Method B) Polyvinylidene chloride resin (manufactured by Asahi Kasei Corporation, product name: F216) was dissolved in a mixed organic solvent of toluene and methyl ethyl ketone (weight ratio: toluene / methyl ethyl ketone = 1 / 2) to prepare a polyvinylidene chloride resin solution (solid content 5% by mass), and coating material B was obtained. Coating material B was coated onto the substrate layer using a Mayer bar and heated in an oven at 70°C for 60 seconds to form a barrier resin layer with a thickness of 500 nm.

[0114] (Method C) 77 g of water, 13.4 g of isopropyl alcohol, and 1.8 g of 0.5 N hydrochloric acid were mixed to obtain a solution of pH 2.2. 35 g of tetraethoxysilane and 1.8 g of a silane coupling agent (manufactured by Shin-Etsu Silicones Co., Ltd., trade name: KBM-403) were mixed with this solution to obtain solution (1-C). Next, 5.9 g of polyvinyl alcohol (manufactured by Nippon Vinegar Vipovale Co., Ltd., trade name: PVA-VI), 129.6 g of water, and 6.8 g of isopropyl alcohol were mixed to obtain solution (2-C). Solution (1-C) and solution (2-C) were mixed in a weight ratio of 6.5:3.5 to prepare coating material C. Coating material C was coated on the substrate layer using a Mayer bar and heated in an oven at 70 ° C for 60 seconds to form a barrier resin layer with a thickness of 300 nm.

[0115] (Examples 7 to 12 and Comparative Examples 4 to 6) In Examples 7 to 12 and Comparative Examples 4 to 6, an anchor coat layer was formed on the corona-treated surface of the substrate layer by the following method. Next, a barrier resin layer was formed on the anchor coat layer under the conditions shown in Table 3 to produce a laminate film. Note that in none of the Examples and Comparative Examples was curling or film cracking observed in the barrier resin layer.

[0116] (Method of forming anchor coat layer) A solvent-based polyisocyanate (manufactured by Mitsui Chemicals, Inc., product name: Takenate D-110N) was coated onto the substrate layer using a Mayer bar, and the coating was dried at 100°C for 15 seconds to obtain a coating amount of 0.1 g / m. ２ An anchor coat layer of the above was formed.

[0117] 5. Preparation of Multilayer Film An adhesive (12 parts by mass of a polyester adhesive (manufactured by Mitsui Chemicals, Inc., product name: T.U.X.MCS)) was applied to one side of a 50 μm thick unstretched LLDPE film (manufactured by Mitsui Chemicals, Inc., product name: T.U.X.MCS). After drying, the laminate film and the LLDPE film were laminated (dry laminated) so that the surface of the barrier resin layer side of the laminate film came into contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film.

[0118] 6. Evaluation of Multilayer Film (1) Peel Strength Using the resulting multilayer film, the 180° peel strength and 90° peel strength between the laminated film and the LLDPE film were measured at 25°C and a pulling rate of 300 mm / min.

[0119] (2) Moisture Permeability The obtained multilayer film was folded over so that the LLDPE film was on the inner side, and the two sides were heat-sealed to form a bag. Calcium chloride was then placed in the obtained bag. The other side of the bag was then heat-sealed to form a bag with a surface area of ​​0.01 m. ２ The bags were then stored at 40°C and 90% RH for 300 hours. The weight of the calcium chloride was measured before and after storage, and the moisture permeability was calculated from the difference.

[0120] (3) Oxygen permeability The oxygen permeability (mL / (m ２ The thermal expansion coefficient (Tc) was measured in accordance with JIS K7126:2006 under conditions of 20°C and 90% RH.

[0121] (4) Evaluation of boiling treatment and multilayer film after boiling treatment The obtained multilayer film was boiled at 85°C for 30 minutes. The multilayer film after boiling treatment was evaluated in the same manner as in (1) to (3). In all of the Examples and Comparative Examples, no delamination between the laminate film and the LLDPE film was observed after boiling treatment.

[0122] The evaluation results of Examples 1 to 6 and Comparative Examples 1 to 3 are shown in Table 2. The evaluation results of Examples 7 to 12 and Comparative Examples 4 to 6 are shown in Table 3.

[0123]

[0124]

[0125] In Examples 1 to 6, multilayer films were obtained that had improved oxygen barrier properties compared to Comparative Examples 1 to 3. In addition, in Examples 7 to 12, multilayer films were obtained that had improved oxygen barrier properties compared to Comparative Examples 4 to 6.

[0126] This application claims priority based on Japanese Patent Application No. 2024-054839, filed March 28, 2024, the disclosure of which is incorporated herein in its entirety by reference.

[0127] REFERENCE SIGNS LIST 10: Substrate layer 11: Core layer 13: Skin layer 30: Barrier resin layer 50: Anchor coat layer 100: Laminated film

Claims

1. A laminated film comprising: a substrate layer containing high-density polyethylene; and a barrier resin layer containing one or more resins selected from the group consisting of a cured product layer of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound, and a polyvinylidene chloride resin layer.

2. The laminated film according to claim 1, wherein the barrier resin layer comprises a layer of a cured product of a mixture containing a polycarboxylic acid resin, a polyamine resin, and a polyvalent metal compound.

3. The density of the substrate layer is 0.910 g / cm ３ The laminated film according to claim 1 or 2, wherein the above-mentioned 4. The laminated film according to any one of claims 1 to 3, wherein the substrate layer includes a stretched film layer.

5. A laminated film according to any one of claims 1 to 4, wherein the content of the polyethylene polymer in the base layer relative to the entire base layer is 75% by mass or more and 100% by mass or less.

6. The laminate film according to any one of claims 1 to 5, wherein the substrate layer includes a core layer and a skin layer, and the core layer, the skin layer, and the barrier resin layer are arranged in this order.

7. The laminated film according to claim 6, wherein the core layer comprises one or more materials selected from the group consisting of high density polyethylene and linear low density polyethylene.

8. The laminated film according to claim 6 or 7, wherein the skin layer comprises one or more materials selected from the group consisting of high-density polyethylene and linear low-density polyethylene.

9. The laminated film according to any one of claims 6 to 8, wherein the skin layer is in direct contact with at least one surface of the core layer.

10. The laminated film according to any one of claims 1 to 9, wherein the thickness of the substrate layer is 5 μm or more and 100 μm or less.

11. The laminate film according to any one of claims 1 to 10, wherein the ratio of the thickness of the base layer to the total thickness of the laminate film is 50% or more but less than 100%.

12. The laminated film according to any one of claims 1 to 11, wherein the substrate layer and the barrier resin layer are in direct contact with each other.

13. A laminated film according to any one of claims 1 to 11, wherein the barrier resin layer is provided on at least one surface of the substrate layer via an anchor coat layer.

14. In accordance with JIS C2151:2019, when heat-treated at 100°C for 15 minutes, the thermal shrinkage rate in the TD direction of the base layer is X ＴＤ When this is done, X ＴＤ The laminated film according to any one of claims 1 to 13, wherein the modulus is less than 4.4%.

15. In accordance with JIS C2151:2019, when heat-treated at 100°C for 15 minutes, the thermal shrinkage rate in the TD direction of the base layer is X ＴＤ The heat shrinkage rate in the MD direction of the base material layer is X ＭＤ When this is done, X ＭＤ -X ＴＤ The laminated film according to any one of claims 1 to 14, wherein the modulus of elasticity is greater than -3.3% and less than 3.3%.

16. The average linear expansion coefficient in the machine direction of the base layer, measured in accordance with JIS K7197:1991 under conditions of a temperature rise rate of 5°C / min, a tensile load of 0.4 N, and a temperature of 20 to 100°C, is 5.0 x 10 －３ The laminated film according to any one of claims 1 to 15, wherein the temperature is 100°C or lower.

17. In accordance with JIS K7127:1999, the tensile modulus in the MD direction of the substrate layer is measured using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min. １ The tensile modulus of the base material layer in the TD direction is T ２ When this is done, T １ +T ２ The laminated film according to any one of claims 1 to 16, wherein the modulus of elasticity is 1000 MPa or more.

18. In accordance with JIS K7127:1999, the tensile modulus in the TD direction of the substrate layer is measured using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min. ２ When this is done, T ２ The laminated film according to any one of claims 1 to 17, wherein the modulus of elasticity is 520 MPa or more.

19. In accordance with JIS K7127:1999, the tensile modulus in the MD direction of the substrate layer is measured using a tensile tester under conditions of a measurement temperature of 23±2°C, 50±5% RH, and a tensile speed of 5 mm / min. １ When this is done, T １ The laminated film according to any one of claims 1 to 18, wherein the modulus of elasticity is 490 MPa or more.

20. The heat of fusion of the base material layer (ΔH ２ｎｄ 20. The laminated film according to any one of claims 1 to 19, wherein the elongation strength (E) is 158.0 J / g or more. (Method) Using a differential scanning calorimeter (DSC), a first differential scanning calorimetry (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining the temperature at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min was performed in succession, and a second differential scanning calorimetry (2nd Run) consisting of a process of maintaining the temperature at -50°C for 5 minutes and a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min was performed in succession, and the heat of fusion (ΔH ２ｎｄ ) 21. The melting point (T ｍ２ 21. The laminated film according to any one of claims 1 to 20, wherein the temperature (Tc) of the laminated film is 125.0°C or higher. (Method) Using a differential scanning calorimeter (DSC), a first differential scanning calorimetry (1st Run) consisting of a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min, an isothermal process of maintaining the temperature at 200°C for 5 minutes, and a process of decreasing the temperature from 200°C to -50°C at a heating rate of 10°C / min was performed in succession, and a second differential scanning calorimetry (2nd Run) consisting of a process of maintaining the temperature at -50°C for 5 minutes and a process of increasing the temperature from -50°C to 200°C at a heating rate of 10°C / min was performed. The peak temperature of the maximum endothermic peak of DSC curve 2 obtained by the second differential scanning calorimetry was determined as T ｍ２ Let's say 22. A laminate film according to any one of claims 1 to 21, wherein the 180° peel strength between the laminate film and an LLDPE film, measured by the following method, is greater than 1.8 N / 15 mm. (Method) An adhesive is applied to one side of a 50 μm-thick LLDPE film. The laminated film and the LLDPE film are then laminated together so that the surface of the laminated film facing the barrier resin layer is in contact with the adhesive-coated surface of the LLDPE film. The peel strength between the laminated film and the LLDPE film is measured at 25° C. and a pulling rate of 300 mm / min.

23. A laminate film according to any one of claims 1 to 22, wherein the 180° peel strength between the laminate film and an LLDPE film, measured by the following method, is greater than 0.2 N / 15 mm. (Method) An adhesive is applied to one side of a 50 μm-thick LLDPE film. The laminated film and the LLDPE film are then laminated together so that the barrier resin layer side of the laminated film is in contact with the adhesive-coated side of the LLDPE film, thereby obtaining a multilayer film. The resulting multilayer film is then subjected to a boiling treatment at 85°C for 30 minutes. Using the multilayer film after the boiling treatment, the peel strength between the laminated film and the LLDPE film is measured under conditions of 25°C and a tensile speed of 300 mm / min.

24. The moisture permeability of a multilayer film calculated using the following method is 3.6 g / (m ２ The laminated film according to any one of claims 1 to 23, wherein the average curing time is less than 100 seconds. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. The laminated film and the LLDPE film are then laminated together so that the barrier resin layer side of the laminated film is in contact with the adhesive-coated side of the LLDPE film, thereby obtaining a multilayer film. The resulting multilayer film is then folded back so that the LLDPE film faces inward, and the two sides are heat-sealed to form a bag. Calcium chloride is then placed in the resulting bag as the contents. The other side of the bag is then heat-sealed to reduce the surface area to 0.01 m. ２ The resulting bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of the calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference.

25. The moisture permeability of a multilayer film calculated using the following method is 3.7 g / (m ２ The laminated film according to any one of claims 1 to 24, wherein the average curing time is less than 100 seconds. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. The laminated film and the LLDPE film are then laminated together so that the barrier resin layer side of the laminated film is in contact with the adhesive-coated side of the LLDPE film, thereby obtaining a multilayer film. The resulting multilayer film is then subjected to a boiling treatment at 85°C for 30 minutes. The boiled multilayer film is then folded back so that the LLDPE film faces inward, and the two sides are heat-sealed to form a bag. Calcium chloride is then placed in the resulting bag as the contents. The other side of the bag is then heat-sealed to reduce the surface area to 0.01 m. ２ The resulting bag is then stored for 300 hours under conditions of 40°C and 90% RH. The weight of the calcium chloride is measured before and after storage, and the moisture permeability is calculated from the difference.

26. The oxygen permeability of a multilayer film measured by the following method is 9900 mL / (m ２ The laminated film according to any one of claims 1 to 25, wherein the compressive strength is 1 / 2 MPa or less. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film facing the barrier resin layer is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the oxygen permeability (mL / (m ２ The thermal expansion coefficient (Tc) is measured in accordance with JIS K7126:2006 under conditions of 20°C and 90% RH.

27. The oxygen permeability of a multilayer film measured by the following method is 8200 mL / (m ２ The laminated film according to any one of claims 1 to 26, wherein the compressive strength is 1 / 2 MPa or less. (Method) An adhesive is applied to one side of a 50 μm thick LLDPE film. Next, the laminated film and the LLDPE film are laminated together so that the surface of the laminated film facing the barrier resin layer is in contact with the adhesive-coated surface of the LLDPE film, thereby obtaining a multilayer film. Next, the obtained multilayer film is subjected to a boiling treatment at 85° C. for 30 minutes. The oxygen permeability (mL / (m ２ The thermal expansion coefficient (Tc) is measured in accordance with JIS K7126:2006 under conditions of 20°C and 90% RH.

28. The laminated film according to any one of claims 1 to 27, which is a packaging film.

29. A packaging material comprising the laminated film according to any one of claims 1 to 28.

30. The packaging material of claim 29, further comprising a heat seal layer on at least one outermost layer.

31. The packaging material according to claim 30, comprising the base material layer, the barrier resin layer, and the heat seal layer in this order.

32. The packaging material of claim 30 or 31, wherein the heat seal layer comprises polyethylene.

33. The packaging material according to any one of claims 29 to 32, further comprising a coating layer on at least one surface of the laminated film.

34. A package comprising the packaging material according to any one of claims 29 to 33 and an article inside the packaging material.

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