Gas barrier films and barrier laminates

Abstract

This gas barrier film comprises: a base material layer, the main component of which is polypropylene or polyethylene; a gas barrier layer which is formed on a first surface side of the base material layer; and a heat seal layer which is formed on a second surface on the opposite side from the first surface, and the main component of which is polypropylene or polyethylene. The peel strength between the base material layer and the heat seal layer is 1.0-7.0 N / 15 mm in 180° peeling in conformance with JIS K 6854-2, and is 1.0 N / 15 mm to 4.0 mm / 15 mm in T-shape peeling in conformance with JIS K 6854-3.

Description

Technical Field

[0001] The present invention relates to a gas barrier film using a resin substrate. A barrier laminate using this gas barrier film is also mentioned. This application claims priority from Japanese Patent Application No. 2022-111829 filed in Japan on July 12, 2022, and Japanese Patent Application No. 2022-111830 filed in Japan on July 12, 2022, and incorporates the contents herein by reference.

Background Art

[0002] A gas barrier film is a film having a property (gas barrier property) of not allowing oxygen, water vapor, etc. to pass through. From the viewpoint of suppressing the deterioration of the contents and maintaining their functions and properties, it is widely used in various fields that require blocking of various gases, such as packaging of precision electronic components, electronic members, foods, and pharmaceuticals.

[0003] In recent years, due to the increasing environmental awareness triggered by problems such as marine plastic waste, there is a growing demand for more efficient separation, recycling, and reuse of plastic materials. This is also true for gas barrier films that have been made more performant by combining various different materials, and there is a growing demand for them to be made of single materials.

[0004] In order to achieve single-materialization, it is necessary to increase the ratio of the resin most commonly used in gas barrier films. As an example of such a configuration, Patent Document 1 discloses a barrier film using polyethylene as a base material and forming an aluminum oxide vapor deposition film.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When a gas barrier film is used as an intermediate layer in a multilayer laminate film, adhesion to the adhesive or ink layer is required on the side of the multilayer laminate film where the gas barrier layer is not formed. Patent Document 1 focuses on the adhesion between the substrate and the aluminum oxide vapor-deposited film, but does not pay attention to the side where the vapor-deposited film is not formed.

[0007] Furthermore, peel tests conforming to JIS K 6854-2 and JIS K 6854-3 are widely used as methods for evaluating the adhesion of multilayer laminate films. In these peel tests, a phenomenon called "zipping" may occur, where peeling does not proceed smoothly, but instead alternates between progressing and stopping. When zipping occurs in a peel test (also called a peel test), it may be impossible to accurately evaluate the adhesion of the multilayer laminate film. As a result, it becomes difficult to determine whether the manufactured film satisfies the required characteristics.

[0008] Based on the above circumstances, the present invention aims to provide a gas barrier film and a barrier laminate that exhibit good adhesion to surfaces where a gas barrier layer is not formed and that can be easily manufactured as a single material. [Means for solving the problem]

[0009] The present invention has the following aspects.

[0010] [1] A gas barrier film comprising a base layer mainly composed of polypropylene or polyethylene, a gas barrier layer formed on the first side of the base layer, and a heat seal layer mainly composed of polypropylene or polyethylene formed on the second side opposite to the first side, wherein the peel strength between the base layer and the heat seal layer is 1.0 N / 15 mm or more and 7.0 N / 15 mm or less in a 180° peel according to JIS K 6854-2, and 1.0 N / 15 mm or more and 4.0 mm / 15 mm or less in a T-shaped peel according to JIS K 6854-3.

[0011] [2] The polarity component value of the surface free energy of the second surface opposite to the first surface is 0.1 mJ / m 2 The gas barrier film described above [1].

[0012] [3] The second surface opposite to the first surface is made of a copolymer, and the polar component value of the surface free energy is 0.1 mJ / m 2 The gas barrier film described above [1].

[0013] [4] The polarity component value of the surface free energy of the second surface is 1.3 mJ / m 2 A gas barrier film as described in any one of items [1] to [3], which is less than [1].

[0014] [5] The gas barrier film according to any one of [1] to [4], wherein the gas barrier layer contains at least one of silicon oxide, carbon-containing silicon oxide, silicon nitride, metallic aluminum, and aluminum oxide.

[0015] [6] The gas barrier film according to any one of [1] to [5], wherein the first surface is made of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and an ethylene vinyl alcohol copolymer.

[0016] [7] A gas barrier film according to any one of [1] to [6], further comprising a coating layer formed on the gas barrier layer, wherein the coating layer contains one of a metal alkoxide, a hydrolysate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid polymer, a polyvalent metal compound, and a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid polymer and a polyvalent metal compound.

[0017] [8] The gas barrier film according to any one of [1] to [7], further comprising an undercoat layer provided between the first surface and the gas barrier layer, wherein the undercoat layer comprises at least one of a thermosetting resin, a thermoplastic resin, an ultraviolet curing resin, and an electron beam curing resin.

[0018] [9] The gas barrier film according to [1] or [2], wherein the peel strength between the base material layer and the heat seal layer is 2.0 N / 15 mm or more and 7.0 N / 15 mm or less in a 180° peel according to JIS K 6854-2.

[10] The gas barrier film according to [3] wherein the difference between the maximum and minimum values ​​of the peel strength at 180° peel is less than 0.3 N / 15 mm.

[0019] A barrier laminate comprising a gas barrier film according to any one of items [1] to

[10] , and a heat seal layer having the same main component as the substrate layer and bonded to the gas barrier film.

[0020]

[12] The barrier laminate according to

[11] , further comprising a surface layer bonded to the gas barrier film, wherein the main component is the same as that of the base layer.

[0021]

[13] The barrier laminate according to

[12] , wherein at least one of the heat seal layer and the surface layer is bonded to the gas barrier film with an adhesive.

[0022]

[14] The barrier laminate according to

[12] or

[13] , wherein the surface layer has a printed layer on at least one surface.

[0023] In one aspect, the present invention has the following characteristics. [A1] A gas barrier film comprising a base layer mainly composed of polypropylene or polyethylene, and a gas barrier layer formed on the first surface side of the base layer. In this gas barrier film, the polar component value of the surface free energy of the second surface opposite the first surface is 0.1 mJ / m2 It is less than.

[0024] [A2] The polar component value of the surface free energy of the second surface is 1.3 mJ / m 2 A gas barrier film as described in [A1], which is less than [A1].

[0025] [A3] The gas barrier film according to [A1] or [A2], wherein the gas barrier layer contains at least one of silicon oxide, carbon-containing silicon oxide, silicon nitride, metallic aluminum, and aluminum oxide.

[0026] [A4] The gas barrier film according to any one of [A1] to [A3], wherein the first surface is made of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and an ethylene vinyl alcohol copolymer.

[0027] [A5] A gas barrier film according to any one of [A1] to [A4], further comprising a coating layer formed on the gas barrier layer, wherein the coating layer contains one of a metal alkoxide, a hydrolysate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid polymer, a polyvalent metal compound, and a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid polymer and a polyvalent metal compound.

[0028] [A6] The gas barrier film according to any one of [A1] to [A5], further comprising an undercoat layer provided between the first surface and the gas barrier layer, wherein the undercoat layer comprises at least one of a thermosetting resin, a thermoplastic resin, an ultraviolet curing resin, and an electron beam curing resin.

[0029] [A7] A barrier laminate comprising a gas barrier film relating to any one of [A1] to [A6] and a heat-seal layer having the same main component as the substrate layer and bonded to the gas barrier film.

[0030] [A8] The barrier laminate according to [A7], further comprising a surface layer bonded to the gas barrier film, wherein the main component is the same as that of the base layer.

[0031] [A9] The barrier laminate according to [A8], wherein at least one of the heat seal layer and the surface layer is bonded to the gas barrier film by an adhesive.

[0032] [A10] The barrier laminate according to [A8] or [A9], wherein the surface layer has a printed layer on at least one surface.

[0033] Another aspect of the present invention is as follows: [B1] A gas barrier film comprising a base layer mainly composed of polypropylene or polyethylene, and a gas barrier layer formed on the first surface side of the base layer. In this gas barrier film, the second surface opposite the first surface is composed of a copolymer, and the polar component value of the surface free energy is 0.1 mJ / m 2 It is less than.

[0034] [B2] The polarity component value of the surface free energy of the second surface is 1.3 mJ / m 2 A gas barrier film as described in [B1], which is less than [B1].

[0035] [B3] The gas barrier film according to [B1] or [B2], wherein the gas barrier layer contains at least one of silicon oxide, carbon-containing silicon oxide, silicon nitride, metallic aluminum, and aluminum oxide.

[0036] [B4] The gas barrier film according to any one of [B1] to [B3], wherein the first surface is made of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and an ethylene vinyl alcohol copolymer.

[0037] [B5] A gas barrier film according to any one of [B1] to [B4], further comprising a coating layer formed on the gas barrier layer, wherein the coating layer contains one of a metal alkoxide, a hydrolysate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid polymer, a polyvalent metal compound, and a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid polymer and a polyvalent metal compound.

[0038] [B6] The gas barrier film according to any one of [B1] to [B5], further comprising an undercoat layer provided between the first surface and the gas barrier layer, wherein the undercoat layer comprises at least one of a thermosetting resin, a thermoplastic resin, an ultraviolet curing resin, and an electron beam curing resin.

[0039] A barrier laminate comprising a gas barrier film relating to any one of items [B7], [B1], to [B6], and a heat-seal layer having the same main component as the substrate layer and bonded to the gas barrier film.

[0040] [B8] The barrier laminate according to [B7], further comprising a surface layer bonded to the gas barrier film, wherein the main component is the same as that of the base layer.

[0041] [B9] The barrier laminate according to [B8], wherein at least one of the heat seal layer and the surface layer is bonded to the gas barrier film by an adhesive.

[0042] [B10] The barrier laminate according to [B8] or [B9], wherein the surface layer has a printed layer on at least one surface. [Effects of the Invention]

[0043] According to the present invention, it is possible to provide a gas barrier film and a barrier laminate that exhibit good adhesion to surfaces where a gas barrier layer is not formed and that can be easily made into a single material. [Brief explanation of the drawing]

[0044] [Figure 1] This is a schematic cross-sectional view of a gas barrier film according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view showing an example of a barrier laminate using the gas barrier film. [Figure 3] This is a schematic cross-sectional view showing another example of a barrier laminate using the same gas barrier film. [Figure 4] This graph shows the results of the peel test for the comparative example. [Modes for carrying out the invention]

[0045] <First Embodiment> Hereinafter, a first embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view of the gas barrier film 1 according to this embodiment. The gas barrier film 1 comprises a base layer 10, a gas barrier layer 20 formed on the first surface 10a of the base layer 10, and a covering layer 30 that covers the gas barrier layer 20.

[0046] The base layer 10 is a resin film mainly composed of polypropylene or polyethylene. The base layer 10 may be either an unstretched film or a stretched film. When a stretched film is used, there are no particular restrictions on the stretching ratio. There are also no particular restrictions on the thickness of the base layer 10. The base layer 10 can be a single-layer film or a multilayer film formed by laminating films with different properties, taking into consideration the application of the packaging material. Considering the processability when forming the gas barrier layer 20 and the coating layer 30, the thickness of the base layer 10 is practically preferably in the range of 3 to 200 μm, and particularly preferably 6 to 50 μm. The form of the base layer 10 may be a long material or a sheet cut to a predetermined size, but a long base material is preferably used. The length in the longitudinal direction of a long base layer 10 is not particularly limited, but for example, a long film of 10 m or more is preferably used. Since there is no upper limit to the length, for example, it may be about 10 km long, in which case it can be rolled up to allow for efficient transportation and storage.

[0047] The "main component" of the base layer 10 refers to the substance with the largest mass among the materials that make up the base layer 10. In this embodiment, the "main component" of each component refers to the substance with the largest mass among the materials that make up each component. When the main component of the base layer 10 is polypropylene, the main component of the base layer 10 is not limited to a resin polymerized solely from propylene, but can also be a resin containing substances other than propylene. For example, copolymers obtained by copolymerizing polyethylene such as HDPE (high-density polyethylene), MDPE (medium-density polyethylene), LDPE (low-density polyethylene), and LLDPE (linear low-density polyethylene) with propylene in a proportion of 0.1 to several tens of percent, or polymers obtained by copolymerizing α-olefin resins such as 1-butene and / or rubber components such as elastomers with propylene or ethylene in a proportion of 0.1 to several tens of percent, can also be used. Furthermore, instead of copolymerization, a layer can be made in which multiple types of resins are mixed and dispersed.

[0048] When polyethylene is the main component of the base layer 10, the polyethylene resin can be selected from or a combination of HDPE, LDPE, MDPE, and LLDPE. Furthermore, copolymers or polymers obtained by copolymerizing 0.1 to several tens of percent of ethylene with α-olefin resins such as 1-butene and / or rubber components such as elastomers can also be used.

[0049] The base layer 10 may be a multilayer film formed by laminating films with different properties. In this case, the base layer 10 may have a layer made of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and ethylene vinyl alcohol copolymer on the surface that becomes the first surface 10a. When the base layer 10 is multilayered, the base layer 10 may have a layer mainly composed of polypropylene or polyethylene and a layer that does not contain the said main component. For example, if the layer constituting the first surface 10a is made only of PVA (polyvinyl alcohol) or EVOH (ethylene vinyl alcohol copolymer), the barrier properties of the gas barrier film 1 can be improved. A substrate layer 10 (also called a multilayer substrate) having multiple layers can be formed by laminating multiple films using an adhesive or by co-extrusion using multiple screws. Although the boundaries between layers of a multilayer substrate formed by co-extrusion cannot be clearly seen when observed with an optical microscope, the boundaries between layers can be confirmed by staining the substrate appropriately and observing the cross-section with a transmission electron microscope (TEM).

[0050] The base layer 10 may contain additives other than resin components. These additives can be appropriately selected from a variety of known additives. Examples of additives include antiblocking agents (AB agents), heat stabilizers, weather stabilizers, UV absorbers, lubricants, slip agents, nucleating agents, antistatic agents, antifogging agents, pigments, and dyes. The AB agents may be organic or inorganic. These additives may be used individually or in combination of two or more. Of these, lubricants and slip agents are preferred additives from the viewpoint of processability. The content of the additives in the base layer 10 can be appropriately adjusted within a range that does not hinder the effect of the gas barrier film in this embodiment.

[0051] The gas barrier layer 20 is a layer of one or more of the following as its main components: silicon oxide, silicon oxide containing carbon, silicon nitride, metallic aluminum, and aluminum oxide, and exhibits barrier properties against a predetermined gas such as oxygen or water vapor. In the gas barrier layer 20, there may be multiple main components with the highest mass. The gas barrier layer 20 may be transparent or opaque.

[0052] The thickness of the gas barrier layer 20 varies depending on the type of components used, composition, and deposition method, but can generally be set appropriately within the range of 3 to 300 nm. If the thickness of the gas barrier layer 20 is less than 3 nm, a uniform film may not be obtained, or the film thickness may be insufficient, and the gas barrier layer may not fully perform its function. If the thickness of the gas barrier layer 20 exceeds 300 nm, cracks may form in the gas barrier layer 20 due to external factors such as bending and stretching after deposition, potentially causing it to lose its barrier properties. A thickness of the gas barrier layer 20 is more preferably within the range of 6 to 150 nm.

[0053] There are no restrictions on the method of forming the gas barrier layer 20; for example, vacuum deposition, plasma-activated deposition, ion beam deposition, ion plating, sputtering, and plasma vapor deposition (CVD) can be used. By combining plasma-assisted methods or ion beam-assisted methods, the gas barrier layer 20 can be formed more densely, improving its barrier properties and adhesion.

[0054] The coating layer 30 covers and protects the gas barrier layer 20, and further enhances the barrier properties of the gas barrier film 1. The coating layer 30 has an optional configuration and can be omitted. The coating layer 30 can be made from a thermoplastic resin, a thermosetting resin, an ultraviolet curing resin, a metal alkoxide or its hydrolysate, a water-soluble polymer, a polycarboxylic acid polymer, a polyvalent metal compound, or a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid polymer and a polyvalent metal compound. A coating layer containing a metal alkoxide and a water-soluble polymer, which have excellent oxygen barrier properties, is particularly preferred. This coating layer is formed using a coating agent mainly composed of an aqueous solution or a water / alcohol mixture containing a water-soluble polymer and one or more metal alkoxides or their hydrolysates. For example, a coating agent can be prepared by dissolving a water-soluble polymer in an aqueous solvent (water or a water / alcohol mixture) and mixing it with a metal alkoxide, either directly or after being treated by hydrolysis. After applying this coating agent onto the gas barrier layer 20, the coating layer 30 can be formed by drying.

[0055] The components of the coating agent used to form the coating layer 30 will be described in more detail. Examples of water-soluble polymers used in the coating agent include PVA, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. In particular, PVA is preferred because it provides excellent gas barrier properties. PVA is generally obtained by saponifying polyvinyl acetate. As PVA, either so-called partially saponified PVA, in which several tens of percent of acetate groups remain, or fully saponified PVA, in which only a few percent of acetate groups remain, can be used. PVA intermediate between the two may also be used.

[0056] Metal alkoxides used as coating agents are compounds that can be represented by the general formula M(OR)n (M: metal such as Si or Al, R: alkyl group such as CH3 or C2H5). Specifically, examples include tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum Al[OCH(CH3)2]3. Examples of silane coupling agents include compounds having epoxy groups such as 3-glycidoxypropyltrimethoxysilane, compounds having amino groups such as 3-aminopropyltrimethoxysilane, compounds having mercapto groups such as 3-mercaptopropyltrimethoxysilane, compounds having isocyanate groups such as 3-isocyanatetopropyltriethoxysilane, and tris-(3-trimethoxysilylpropyl)isocyanurate.

[0057] Polycarboxylic acid polymers are polymers having two or more carboxyl groups in their molecule. Examples of polycarboxylic acid polymers include (co)polymers of ethylenically unsaturated carboxylic acids; copolymers of ethylenically unsaturated carboxylic acids with other ethylenically unsaturated monomers; and acidic polysaccharides having carboxyl groups in their molecule, such as alginic acid, carboxymethylcellulose, and pectin. Examples of ethylenically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of ethylenically unsaturated monomers copolymerizable with ethylenically unsaturated carboxylic acids include ethylene, propylene, vinyl acetate and other saturated vinyl carboxylic acid esters, alkyl acrylates, alkyl methacrylates, alkyl itaconates, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. These polycarboxylic acid polymers may be used individually or in combination of two or more types.

[0058] From the viewpoint of gas barrier properties, polymers containing structural units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid are preferred, and polymers containing structural units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid are particularly preferred. In the above polymer, the proportion of structural units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 80 mol% or more, and more preferably 90 mol% or more (provided that the total of all structural units constituting the polymer is 100 mol%). This polymer may be a homopolymer or a copolymer. If the polymer is a copolymer containing structural units other than the above structural units, examples of other structural units include structural units derived from ethylenically unsaturated monomers copolymerizable with the aforementioned ethylenically unsaturated carboxylic acids.

[0059] The number-average molecular weight of the polycarboxylic acid polymer is preferably in the range of 2,000 to 10,000,000, and more preferably in the range of 5,000 to 1,000,000. If the number-average molecular weight is less than 2,000, the water resistance of the gas barrier film may be insufficient depending on the application, and moisture may cause deterioration of gas barrier properties and transparency, or whitening may occur. On the other hand, if the number-average molecular weight exceeds 10,000,000, the viscosity of the coating agent may increase, impairing the coating properties. In this embodiment, the number-average molecular weight is the number-average molecular weight on a polystyrene basis, determined by gel permeation chromatography (GPC).

[0060] Various additives can be added to coating agents mainly composed of polycarboxylic acid polymers, and crosslinking agents, curing agents, leveling agents, defoaming agents, antiblocking agents, antistatic agents, dispersants, surfactants, softeners, stabilizers, film-forming agents, and thickeners may be added as long as they do not impair the barrier performance.

[0061] For coating agents mainly composed of polycarboxylic acid polymers, an aqueous medium is preferred as the solvent. Examples of aqueous mediums include water, water-soluble or hydrophilic organic solvents, or mixtures thereof. The aqueous medium is usually water or mainly composed of water. The water content in the aqueous medium is preferably 70% by mass or more, and more preferably 80% by mass or more. Examples of water-soluble or hydrophilic organic solvents include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosolves; carbitols; and nitriles such as acetonitrile.

[0062] The polyvalent metal compound is not particularly limited as long as it is a compound that reacts with the carboxyl group of the polycarboxylic acid polymer to form a polyvalent metal salt of the polycarboxylic acid, and examples include zinc oxide particles, magnesium oxide particles, magnesium methoxide, copper oxide, and calcium carbonate. These may be used individually or in combination. From the viewpoint of the oxygen barrier properties of the oxygen barrier film, zinc oxide particles are preferred among the above. Zinc oxide is an inorganic material that has ultraviolet light absorption ability. The average particle size of zinc oxide particles is not particularly limited, but from the viewpoint of gas barrier properties, transparency, and coating suitability, the average particle size is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0063] When applying and drying a coating agent mainly composed of a polyvalent metal compound to form a film, various additives may be included in the coating agent in addition to zinc oxide particles, as needed, to the extent that the effects of this embodiment are not impaired. These additives may include resins soluble or dispersible in the solvent used in the coating agent, dispersants soluble or dispersible in the solvent, surfactants, softeners, stabilizers, film-forming agents, and thickeners. Among these, it is preferable to include a resin soluble or dispersible in the solvent used in the coating agent. This improves the coatability and film-forming properties of the coating agent. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenolic resins, amino resins, fluororesins, epoxy resins, and isocyanate resins. It is also preferable to include a dispersant soluble or dispersible in the solvent used in the coating agent. This improves the dispersibility of the polyvalent metal compound. Anionic surfactants or nonionic surfactants can be used as the dispersant. Examples of such surfactants include (poly)carboxylates, alkyl sulfates, alkylbenzene sulfons, alkylnaphthalene sulfons, alkyl sulfosuccinates, alkyl diphenyl ether disulfons, alkyl phosphates, aromatic phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, alkyl allyl sulfates, polyoxyethylene alkyl phosphates, sorbitan alkyl esters, glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene sorbitan alkyl esters, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxy fatty acid esters, and polyoxyethylene alkylamines. These surfactants may be used individually or in combination of two or more.When a coating agent mainly composed of a polyvalent metal compound contains additives, the mass ratio of the polyvalent metal compound to the additive (polyvalent metal compound:additive) is preferably in the range of 30:70 to 99:1, and preferably in the range of 50:50 to 98:2.

[0064] Examples of solvents used in coating agents mainly composed of polyvalent metal compounds include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used individually or in mixtures of two or more. Among these, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred from the viewpoint of coating properties. Furthermore, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred from the viewpoint of manufacturability.

[0065] When a coating agent mainly composed of a polycarboxylic acid polymer is applied and dried to form a film, and then a film of a polyvalent metal compound is formed, some of the carboxyl groups of the polycarboxylic acid polymer may be neutralized in advance with a basic compound. By neutralizing some of the carboxyl groups of the polycarboxylic acid polymer in advance, the water resistance and heat resistance of the film made of the polycarboxylic acid polymer can be further improved. As the basic compound, at least one basic compound selected from the group consisting of the above-mentioned polyvalent metal compounds, monovalent metal compounds, and ammonia is preferred. Examples of monovalent metal compounds include sodium hydroxide and potassium hydroxide.

[0066] When applying and drying a coating agent that is a mixture of a polycarboxylic acid polymer and a polyvalent metal compound to form a film, the coating agent is prepared by mixing the polycarboxylic acid polymer, the polyvalent metal compound, water or alcohols as a solvent, a resin or dispersant that can be dissolved or dispersed in the solvent, and additives as needed. The coating layer 30 can also be formed by applying and drying such a coating agent using a known coating method.

[0067] Conventional coating methods can be used for coating the coating layer 30. For example, well-known methods such as dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset method, and organic vapor deposition can be used. For drying, one or more heat-applying methods such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, and electron beam irradiation can be used. Alternatively, a film pre-coated on another resin substrate using the above forming method may be transferred to the gas barrier layer 20 using transfer methods such as adhesive transfer, heat transfer, or UV transfer.

[0068] The thickness of the coating layer 30 varies depending on the composition of the coating agent used and the coating conditions, and there are no particular restrictions. However, if the drying thickness of the coating layer 30 is less than 0.01 μm, a uniform coating film may not be formed, and sufficient gas barrier properties may not be obtained. If the drying thickness exceeds 50 μm, cracks are more likely to occur in the coating layer 30. Therefore, a suitable thickness for the coating layer 30 is, for example, in the range of 0.01 to 50 μm, and the optimal thickness for the coating layer 30 is, for example, in the range of 0.1 to 10 μm.

[0069] The gas barrier film 1 having the above-described structure can be widely used in applications where it constitutes a part of various laminates having barrier properties (hereinafter sometimes collectively referred to as "barrier laminates"). In this case, various layers are provided on the second surface 10b of the base layer 10 and on the gas barrier layer 20 or coating layer 30 on the opposite side. Therefore, in order to improve the quality of the barrier laminate produced using the gas barrier film 1, good adhesion with the layer provided on the second surface 10b is required.

[0070] The inventors conducted various studies to improve the adhesion with the layer provided on the second surface 10b. As a result, it was found that by setting the polar component value of the surface free energy of the second surface to 0.1 mJ / m 2 or more, good adhesion with the layer provided thereon can be achieved.

[0071] Surface free energy is the energy derived from the intermolecular forces on the surface. While surface tension is regarded as the tension acting per unit length, surface free energy is regarded as the energy (work) acting per unit area, and is used to explain phenomena where the wetting relationship does not depend only on the magnitude of the surface tension. Surface free energy can be calculated based on the contact angles with the measurement target surface measured using a plurality (for example, two or three types) of liquids for which the values of the respective components (polar component, dispersion component) constituting the surface free energy are known.

[0072] When the gas barrier film 1 is wound in a roll or stored in a stacked sheet state with a large number of sheets, a phenomenon called blocking may occur, in which the gas barrier films adjacent to each other in the thickness direction stick together and are difficult to peel off. When blocking occurs, the operation of feeding out the gas barrier film 1 from the roll becomes complicated, etc., thereby reducing the manufacturing efficiency of the barrier laminate using the gas barrier film 1. In the study by the inventors, it was found that by setting the polar component value of the surface free energy of the second surface to less than 1.3 mJ / m 2 the occurrence of blocking can be reduced.

[0073] The polar component value of the surface free energy of the second surface 10b can be adjusted by subjecting the second surface 10b to corona treatment, plasma treatment, ozone treatment, flame treatment, etc., or by forming a coating layer containing a thermoplastic resin, a thermosetting resin, or an ultraviolet curable resin on the second surface 10b. Of the methods described above, plasma treatment is particularly preferred from the viewpoint of ease of adjusting the polarity component value of the surface free energy. Argon or oxygen can be used for plasma treatment.

[0074] In the gas barrier film 1 according to this embodiment, it is sufficient that the polarity component value of the surface free energy of the second surface 10b satisfies predetermined conditions, and there are no particular restrictions on the material of the second surface. Therefore, if the main component of the base layer 10 is polyethylene or polypropylene, the second surface 10b may be composed of a layer that does not contain either polyethylene or polypropylene.

[0075] The gas barrier film 1 of this embodiment, having the above configuration, exhibits high gas barrier properties. Furthermore, the base layer 10 is mainly composed of polyethylene or polypropylene, and it is easy to make the ratio of polyethylene or polypropylene in the gas barrier film 1 90% by mass or more. In other words, the gas barrier film 1 can be easily made into a highly recyclable monomaterial, and environmental compliance can be easily achieved.

[0076] An example of the configuration of a barrier laminate using gas barrier film 1 is described below. The barrier laminate 101 shown in Figure 2 has a configuration in which a heat-sealable heat-seal layer 40 is provided on the second surface 10b of the gas barrier film 1. By heat-sealing the peripheral edges of two or one folded barrier laminate 101 with the heat-seal layers 40 facing each other, a packaging material such as a pouch made of barrier laminate 101 can be formed, resulting in a package that seals the contents it contains.

[0077] Polypropylene or polyethylene can be used as the material for the heat seal layer 40, and it can be a single layer or a multi-layer structure. By making the main component of the heat seal layer 40 the same as that of the base layer 10, the barrier laminate 101 can be made of a single material. In this case, the same film as the base layer 10 can also be used as the heat seal layer 40.

[0078] Polyolefin resin components such as polypropylene and polyethylene have extremely low polarity (degree of positive and negative polarization within the molecule). For this reason, heat-seal layers mainly composed of polypropylene or polyethylene are difficult to bond to the substrate layer 10 by either extrusion lamination or dry lamination. However, in the gas barrier film 1, the polar component of the surface free energy of the second surface 10b is 0.1 mJ / m 2 Therefore, the bonding performance with the heat seal layer is significantly improved. In particular, in dry lamination, the polar component of the surface free energy of the second surface 10b is 0.1 mJ / m 2 As a result, the adhesive spreads uniformly, and interactions occur between the molecules constituting the second surface 10b and the adhesive molecules. This allows the resin film that forms the heat seal layer to be joined with a high adhesion force of 1 N / 15 mm or more, as measured in accordance with, for example, JIS K 6854-2 (180° peel) or JIS K 6854-3 (T-type peel). Furthermore, the inventors have found that in the gas barrier film 1 equipped with the heat seal layer 40 according to this embodiment, the peel strength between the base layer 10 and the heat seal layer 40 is 2.0 N / 15 mm or more in a 180° peel test in accordance with JIS K 6854-2, which results in good adhesion of the second surface 10b of the base layer 10 and suppression of zipping in peel tests.

[0079] The thickness of the heat seal layer 40 can be determined according to the purpose, but for example, it can be about 15 to 200 μm. The heat seal layer 40 may be bonded to the gas barrier film 1 by dry lamination using an adhesive, or the heat seal layer 40 may be provided by extrusion lamination using a fluid resin that will become the heat seal layer.

[0080] The barrier laminate 102 shown in Figure 3 has a configuration in which a surface layer 60 is further bonded to the gas barrier layer 20 of the barrier laminate 101 via an adhesive layer 50. The main component of the surface layer 60 may be the same as that of the base layer 10. The method of bonding the surface layer 60 may be the same as the method of bonding the heat seal layer 40 described above. At least one of the heat seal layer 40 and the surface layer 60 may be bonded to the gas barrier film 1 with an adhesive. The surface layer 60 has a printed layer 61 on one side, and is bonded to the gas barrier layer 20 with the printed layer 61 facing it. The printed layer 61 may also be provided on the side of the surface layer 60 opposite to the side facing the gas barrier layer 20. When forming a packaging material using a barrier laminate 101, the gas barrier layer 20 constitutes the outer surface of the packaging material. However, in a packaging material formed using a barrier laminate 102, the surface layer 60 constitutes the outer surface of the packaging material. Therefore, by appropriately setting the material of the surface layer 60, various properties such as the appearance and scratch resistance of the packaging material can be set to the desired content suitable for the application. Furthermore, the printing layer 61 can be easily used to impart the desired appearance and markings. Moreover, by bonding the printing layer 61 to the gas barrier layer 20 facing each other, the user of the packaging material will not come into contact with the printing layer 61, thereby suppressing deterioration of the printing layer due to the use of the packaging material.

[0081] The configuration of the barrier laminate using the gas barrier film 1 is not limited to the examples described above. For example, the arrangement of the surface layer 60 and the heat seal layer 40 may be reversed, or if the barrier laminate is made into a multilayer structure, the heat seal layer 40 may be provided on both sides of the gas barrier film 1. In addition, a coating layer 30 may be provided between the gas barrier layer 20 and the surface layer 60.

[0082] In the gas barrier film of this embodiment, an undercoat layer (not shown) may be provided between the first surface 10a and the gas barrier layer 20. The undercoat layer can improve the adhesion between the substrate layer 10 and the gas barrier layer 20, preventing delamination of the gas barrier layer 20, and can also protect the first surface 10a from mechanical damage such as scratches and abrasions during the transport process before the formation of the gas barrier layer. The material of the undercoat layer is not particularly limited, but examples include thermosetting resins, thermoplastic resins, ultraviolet curable resins, and electron beam curable resins.

[0083] Examples of thermosetting resins used to form the undercoat layer include thermosetting urethane resins composed of acrylic polyol and isocyanate prepolymer, phenolic resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. In particular, an undercoat layer formed from a composite of an acrylic polyol containing an OH group and an isocyanate compound having at least two NCO groups in its molecule can significantly improve the adhesion between the substrate layer 10 and the gas barrier layer 20.

[0084] Acrylic polyols are polymeric compounds obtained by polymerizing (meth)acrylic acid derivative monomers, or polymeric compounds obtained by copolymerizing (meth)acrylic acid derivative monomers with other monomers, which have OH groups at their terminals and side chains and react with the NCO group of isocyanate compounds. (Meth)acrylic acid derivative monomers have OH groups at their terminals and side chains. Examples of (meth)acrylic acid derivative monomers include hydroxyethyl (meth)acrylate and hydroxybutyl (meth)acrylate.

[0085] The above-mentioned "other monomers" can be copolymerized with (meth)acrylic acid derivative monomers having OH groups at their terminals and side chains. Examples of "other monomers" include (meth)acrylic acid derivative monomers having alkyl groups in their side chains, such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and t-butyl (meth)acrylate; (meth)acrylic acid derivative monomers having COOH groups in their side chains, such as (meth)acrylic acid; and (meth)acrylic acid derivative monomers having aromatic rings or cyclic structures in their side chains, such as benzyl (meth)acrylate and cyclohexyl (meth)acrylate. Other examples besides (meth)acrylic acid derivative monomers include styrene monomers, cyclohexyl maleimide monomers, and phenyl maleimide monomers. "Other monomers" themselves may have OH groups at their terminals and side chains.

[0086] The acrylic polyol is preferably a polymer compound obtained by polymerizing a (meth)acrylic acid derivative monomer having a COOH group in its side chain, such as (meth)acrylic acid. When forming the undercoat layer, a gas barrier film with higher water vapor barrier properties can be obtained by using a composite of an acrylic polyol obtained by polymerizing a monomer having a COOH group and an isocyanate compound.

[0087] The acrylic polyol containing OH groups that can be used in the undercoat layer is not particularly limited, but it is desirable that the OH group value is 50 mgKOH / g or more and 250 mgKOH / g or less. Here, the OH group value (mgKOH / g) is an indicator of the amount of OH groups in the acrylic polyol, and indicates the number of mg of potassium hydroxide required to acetylate the OH groups in 1 g of acrylic polyol. Furthermore, the weight-average molecular weight of the acrylic polyol is not particularly limited, but it is preferably 3000 or more and 200000 or less. In particular, it is preferably 5000 or more and 100000 or less. Even more preferably, it is preferably 5000 or more and 40000 or less.

[0088] Isocyanate compounds are those that have two or more NCO groups in their molecule. Examples of monomeric isocyanates include aromatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), and tetramethylxylylene diisocyanate (TMXDI), and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), bisisocyanate methylcyclohexane (H6XDI), isophorone diisocyanate (IPDI), and dicyclohexylmethane diisocyanate (H12MDI). Polymers or derivatives of these monomeric isocyanates can also be used. For example, these include the nurate type of trimer, the adduct type obtained by reacting with 1,1,1-trimethylolpropane, and the biuret type obtained by reacting with biuret.

[0089] The isocyanate compound may be arbitrarily selected from the above-mentioned isocyanate compounds or their polymers or derivatives, and can be used one or more in combination.

[0090] An example of an undercoat layer is formed by coating the first surface 10a of the substrate layer 10 with a solution consisting of a composite of the above-mentioned acrylic polyol and isocyanate compound and a solvent, and allowing it to react and cure. The equivalent ratio of the NCO groups of the isocyanate compound to the OH groups of the acrylic polyol (NCO / OH) is preferably 0.3 or more and 2.5 or less. The solvent used here can be any solvent that can dissolve the above-mentioned acrylic polyol and isocyanate compound. Examples of solvents include methyl acetate, ethyl acetate, butyl acetate, cyclohexanone, acetone, methyl ethyl ketone, dioxolane, and tetrahydrofuran. In practice, one or more of these solvents can be used in combination.

[0091] The thermoplastic resin used to form the undercoat layer can be appropriately selected from polyols having two or more OH groups, such as acrylic polyols, polyester polyols, polycarbonate polyols, polyether polyols, polycaprolactone polyols, and epoxy polyols; polyvinyl resins such as polyvinyl acetate and polyvinyl chloride; polyvinylidene chloride resins; polystyrene resins; polyethylene resins; polypropylene resins; and polyurethane resins. Furthermore, these can be mixed in any ratio. The OH group value of the polyol is not particularly limited, but it is preferably between 10 mg KOH / g and 250 mg KOH / g.

[0092] The UV-curable resin or electron-beam-curable resin forming the undercoat layer is an organic polymer resin, and is not particularly limited, but it is desirable to include at least a resin with an OH group value in the range of 10 to 100 mgKOH / g. Furthermore, the organic polymer resin is not particularly limited, but it is desirable to include at least a resin with an acid value in the range of 10 to 100 mgKOH / g. Here, the acid value (mgKOH / g) indicates the number of mg of potassium hydroxide required to neutralize the free fatty acids, resin acids, etc., contained in 1 g of the sample. It is also desirable to include at least a thermoplastic resin as the organic polymer resin. If the OH group value or acid value is less than 10 mgKOH / g, the chemical bonding force between the functional groups and the surface of the gas barrier layer 20 weakens, and adhesion to the gas barrier layer 20 tends to decrease. If the OH group value or acid value exceeds 100 mgKOH / g, precipitates containing OH groups generated by the decomposition of the undercoat layer in durability tests such as humid heat resistance tests tend to inhibit adhesion between the undercoat layer and the gas barrier layer 20.

[0093] Monomers that can be used in UV-curable or electron-beam-curable resins forming the undercoat layer include, for example, monofunctional monomers such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylprolidone, as well as polyfunctional monomers such as trimethylolpropane (meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and neopentyl glycol (meth)acrylate. Oligomers that can be used in these UV-curable or electron-beam-curable resins include urethane acrylate, epoxy acrylate, and polyester acrylate.

[0094] When two or more organic polymer resins selected from thermosetting resins, thermoplastic resins, UV-curable resins, and electron beam-curable resins are used in combination as the undercoat layer, the mixing ratio is not particularly limited.

[0095] The undercoat layer may contain additives other than the organic polymer resin as needed. Examples of additives include antioxidants, weathering agents, heat stabilizers, lubricants, nucleating agents, UV absorbers, plasticizers, antistatic agents, colorants, fillers, surfactants, and silane coupling agents.

[0096] The thickness of the undercoat layer is preferably between 0.05 μm and 7.0 μm. In particular, it is preferably between 0.05 μm and 0.3 μm. If it is thinner than 0.05 μm, the adhesion between the first surface 10a of the substrate layer 10 and the gas barrier layer 20 will be insufficient. If it is thicker than 7.0 μm, the influence of internal stress will be large, the gas barrier layer 20 will not be properly laminated, the barrier properties will not be sufficiently expressed, and furthermore, transparency and coating accuracy will also be insufficient.

[0097] Conventional coating methods can be used to form the undercoat layer. For example, well-known methods such as dipping, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing, spray coating, gravure offset method, and organic vapor deposition method can be used. For drying, one or more heat-applying methods such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, and electron beam irradiation can be used. Alternatively, a film pre-coated on another resin substrate using the above formation method may be transferred onto the first surface 10a using transfer methods such as adhesive transfer, heat transfer, and UV transfer.

[0098] <Second Embodiment> Next, a second embodiment of the present invention will be described, which has the same basic configuration as the first embodiment. For this reason, the same reference numerals are used for similar components, and their descriptions are omitted; only the differences will be described.

[0099] To accurately evaluate the adhesion of the fabricated barrier laminate, it is important that no zipping occurs during peel tests in accordance with JIS K 6854-2 or JIS K 6854-3. The inventors further investigated a configuration that can reduce the occurrence of zipping between the substrate layer 10 and the bonded layer in a barrier laminate made using the gas barrier film 1. As a result, they found that the occurrence of zipping can be suitably reduced by making the second surface 10b of the substrate layer 10 out of copolymer. Although the mechanism is not fully clear, it is presumed that the flexibility of the layer is improved by making the layer out of copolymer, which makes it less likely for fine cracks that cause zipping to occur during delamination. The copolymer constituting the second surface 10b of the base layer 10 is the copolymer described as the material of the base layer 10 in the first embodiment. If the base layer 10 is multilayer, the base layer 10 may have a layer mainly composed of polypropylene or polyethylene and a layer composed of the copolymer constituting the second surface 10b. Furthermore, there are no particular restrictions on the types or number of monomers that make up the copolymer. Therefore, the copolymer may be composed of three or more types of monomers, and may not contain monomers that are present in the bonded layer, such as ethylene or propylene.

[0100] Based on the findings obtained through the study, in the gas barrier film according to this embodiment, the second surface 10b of the substrate layer 10 is composed of a copolymer, and the polarity component value of the surface free energy of the second surface is 0.1 mJ / m 2 By implementing the above, we succeeded in achieving both high adhesion during the fabrication of barrier laminates and suppression of zipping during peel tests.

[0101] Furthermore, the inventors have found that in the gas barrier film 1 equipped with the heat seal layer 40 according to this embodiment, the peel strength between the base layer 10 and the heat seal layer 40 is 1.0 N / 15 mm or more and 7.0 N / 15 mm or less in a 180° peel test in accordance with JIS K 6854-2, and 1.0 N / 15 mm or more and 4.0 mm / 15 mm or less in a T-shaped peel test in accordance with JIS K 6854-3, resulting in good adhesion to the second surface 10b of the base layer 10 and suppression of zipping in peel tests. If at least one of the peel strengths under the two measurement conditions is below the range, the adhesion to the second surface 10b of the base layer 10 may not reach the desired strength. Also, if at least one of the peel strengths under the two measurement conditions is outside the range, there may be areas where the adhesion between the two layers is excessively weak or strong, and it is thought that zipping is more likely to occur due to variations in adhesion strength at the adhesive surface of the two layers.

[0102] The gas barrier film of this embodiment will be further described using examples and comparative examples. The technical scope of the present invention is not limited solely on the basis of the specific contents of the examples and comparative examples.

[0103] (Example 1) As the base layer 10, a polypropylene film (total thickness 20 μm) with a three-layer structure was used, having an EVOH layer (thickness 1 μm) on the first side, a copolymer layer of polypropylene and polyethylene (thickness 1 μm) on the second side, and a polypropylene homopolymer layer (thickness 18 μm) in the middle between the first and second sides. The main component of this base layer is polypropylene.

[0104] SiO was sublimated in a vacuum chamber, and a gas barrier layer 20 (30 nm thick) made of silicon dioxide (SiOx) was formed on the EVOH layer by electron beam deposition. Furthermore, while maintaining a vacuum, the second surface of the substrate layer 10 is subjected to plasma treatment at an intensity of 67 W·sec / m². 2 Plasma treatment was performed using Ar gas. The plasma treatment intensity was calculated using the following formula. Plasma treatment intensity = power density [W / m²] 2 ] × Processing time [sec] ·Power density [W / m 2 ] = Input power [W] / Cathode area [m²] 2 ] Processing time [sec] = Electrode MD width [m] / Processing speed [m / sec]

[0105] The polarity component of the surface free energy of the second surface after the completion of the gas barrier film was calculated based on the contact angle values ​​of water and diiodomethane measured using a tactile meter (DMs-401, Kyowa Interface Science Co., Ltd.). The contact angle was measured 1 second after application, with an appropriate amount of 2.5 μl of each liquid. The commonly used Owens-Wendt-Rabel-Kaelble (WORK, Kaelble-Uy) method was used to calculate the surface free energy (= polarity component value + dispersion component value) and the values ​​of each component. The polarity component of the surface free energy of the second surface after plasma treatment was 0.1 mJ / m 2 That was the case.

[0106] Next, a coating agent, prepared by mixing liquid A and liquid B in a mass ratio of 6:4, was applied to the gas barrier layer 20 using the gravure coating method and dried to form a coating layer 30 with a thickness of 0.4 μm. Solution A: Hydrolyzed solution with a solid content of 3 wt% (SiO2 equivalent) obtained by adding 89.6 g of hydrochloric acid (0.1 N) to 10.4 g of tetraethoxysilane and stirring for 30 minutes. Solution B: 3 wt% water / isopropyl alcohol solution of polyvinyl alcohol (water:isopropyl alcohol weight ratio 90:10) Based on the above, a gas barrier film according to Example 1 was prepared.

[0107] (Example 2) Plasma treatment intensity set to 100 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 2 was prepared using the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 0.2 mJ / m 2 That was the case.

[0108] (Example 3) Plasma treatment intensity: 300 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 3 was prepared using the same procedure as in Example 1. The polarity component value of the surface free energy of the second surface was 0.4 mJ / m 2 That was the case.

[0109] (Example 4) Plasma treatment intensity: 500 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 4 was prepared using the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 1.0 mJ / m 2 That was the case.

[0110] (Example 5) Plasma treatment intensity set to 100 W·sec / m 2 Except for performing plasma treatment using O2 gas, a gas barrier film according to Example 5 was fabricated using the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 1.3 mJ / m 2 That was the case.

[0111] (Example 6) Plasma treatment intensity: 300 W·sec / m 2Except for the aforementioned point, the gas barrier film according to Example 6 was prepared using the same procedure as in Example 5. The polar component value of the surface free energy of the second surface was 1.6 mJ / m 2 That was the case.

[0112] (Example 7) A gas barrier film according to Example 7 was prepared using the same procedure as in Example 1, except that the base layer 10 was a two-layer polypropylene film (total thickness 20 μm) having a terpolymer (copolymer) layer (thickness 1 μm) composed of polypropylene, polyethylene, and 1-butene on the first surface side, and a polypropylene homopolymer layer (thickness 19 μm) in the layer below the first surface, including the second surface. The polar component value of the surface free energy of the second surface was 0.1 mJ / m 2 That was the case.

[0113] (Example 8) Plasma treatment intensity set to 100 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Example 8 was prepared using the same procedure as in Example 7. The polarity component value of the surface free energy of the second surface was 0.2 mJ / m 2 That was the case.

[0114] (Example 9) Plasma treatment intensity: 300 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Example 9 was prepared using the same procedure as in Example 7. The polarity component value of the surface free energy of the second surface was 0.8 mJ / m 2 That was the case.

[0115] (Example 10) Plasma treatment intensity: 500 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Example 10 was prepared using the same procedure as in Example 7. The polarity component value of the surface free energy of the second surface was 1.2 mJ / m 2 That was the case.

[0116] (Example 11) Plasma treatment intensity set to 100 W·sec / m 2Except for performing plasma treatment using O2 gas, the gas barrier film according to Example 11 was prepared using the same procedure as in Example 7. The polar component value of the surface free energy of the second surface was 1.9 mJ / m 2 That was the case.

[0117] (Example 12) Plasma treatment intensity: 300 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 12 was prepared using the same procedure as in Example 11. The polarity component value of the surface free energy of the second surface was 3.0 mJ / m 2 That was the case.

[0118] (Comparative Example 1) A gas barrier film according to Comparative Example 1 was prepared using the same procedure as in Example 1, except that plasma treatment was not performed on the second surface. The polarity component value of the surface free energy of the second surface was 0.0 mJ / m 2 That was the case.

[0119] (Comparative Example 2) A gas barrier film according to Comparative Example 2 was prepared using the same procedure as in Example 7, except that plasma treatment was not performed on the second surface. The polarity component value of the surface free energy of the second surface was 0.0 mJ / m 2 That was the case.

[0120] The following evaluations were performed on the gas barrier films according to the examples and comparative examples. (Evaluation of adhesion on the second surface) A heat-sealed layer was created on the second surface of the gas barrier film for each example by laminating a 70 μm thick unstretched polypropylene film (Toray Industries ZK207) using a two-component curing polyurethane adhesive. Furthermore, a surface layer was created on the coating layer 30 by laminating a 20 μm thick stretched polypropylene film (Mitsui Chemicals Tohcello U1) using a two-component curing polyurethane adhesive, thereby producing a barrier laminate for each example. Test specimens were cut from each example of barrier laminate according to JIS K 6854-2 for 180° peel and JIS K 6854-3 for T-shaped peel, and the peel strength between the substrate layer and the heat seal layer was measured using an Orientec Tensilon universal tester RTC-1250. Two types of measurements were performed: T-shaped peel and 180° peel. In both T-shaped and 180° peel tests, if the peel strength was 1 N / 15 mm or higher, it can be said that there is sufficient adhesion on the second surface.

[0121] (Blocking evaluation) Two 70mm square samples were cut from each example's gas barrier film and stacked. Using a Tester Industries CO-201 permanent strain testing machine (blocking tester), the stacked samples were subjected to a pressure of 200kg and stored at 50°C for two days. Subsequently, the peel strength between the upper and lower samples was measured using a Shimadzu Autograph in accordance with JIS K 6854-2 and JIS K 6854-3. Specifically, in the blocking evaluation, a peel test was performed between the second surface of the substrate layer of the upper sample and the coating layer of the lower sample. Two types of measurements were performed: T-shaped peeling and 180° peeling. Blocking was defined as occurring if a peel strength of 0.1 N / 15 mm or higher was observed in either measurement. The results are shown in Table 1.

[0122] [Table 1]

[0123] In all the examples shown in Table 1, the peel strength in the adhesion evaluation of the second surface was 1 N / 15 mm or more in T-shaped peeling, confirming that the heat seal layer provided on the second surface side was sufficiently adhered to the substrate layer. In Examples 1 to 6, where the second surface was a copolymer layer, the peel strength was 1 N / 15 mm or more even in 180° peeling. In Examples 7 to 12, where the second surface was a homopolymer layer, the average of the minimum and maximum measured values ​​for 180° peeling was used as the peel strength. In all cases, it was 1 N / 15 mm or higher, confirming sufficient adhesion between the substrate layer and the heat seal layer. In Examples 7 to 12, zipping was observed during 180° peeling. Zipping is a phenomenon in which the peel strength changes intermittently as the peeling surface does not peel smoothly, but rather alternates between peeling progression and stopping. In Table 1, the peel strength of samples in which zipping was observed during 180° peeling is marked with (*). In the 180° peel test for the adhesion evaluation of the second surface, Examples 1 to 6, which satisfy 2.0 N / 15 mm or more, show that the adhesion of the second surface 10b of the substrate layer 10 is good and that the occurrence of zipping in the peel test can be suppressed. Furthermore, the polar component value of the surface free energy of the second surface is 1.3 mJ / m 2 In Examples 1 to 4 and Examples 7 to 10, where the peel strength in the blocking evaluation was less than 0.1 N / 15 mm in both the T-shape and 180° configurations, indicating that blocking was sufficiently suppressed.

[0124] On the other hand, in Comparative Example 1 and Comparative Example 2, although blocking did not occur, the peel strength values ​​in the adhesion evaluation of the second surface were low, indicating insufficient adhesion between the substrate layer and the heat seal layer.

[0125] The present invention will be described in more detail below using other embodiments. The technical scope of the present invention is not limited in any way based solely on the specific details of these embodiments.

[0126] (Example 2-1) As the base layer 10, a polypropylene film (total thickness 20 μm) with a three-layer structure was used, having an EVOH layer (thickness 1 μm) on the first side, a copolymer layer (thickness 1 μm) made of propylene, ethylene, and 1-butene terpolymer on the second side, and a polypropylene homopolymer layer (thickness 18 μm) in the middle between the first and second sides. The main component of this base layer is polypropylene.

[0127] SiO was sublimated in a vacuum chamber, and a gas barrier layer 20 (30 nm thick) made of silicon dioxide (SiOx) was formed on the EVOH layer by electron beam deposition. Furthermore, while maintaining a vacuum, a Reactive Ion Etching (RIE) apparatus is used to apply plasma treatment to the second surface of the substrate layer 10 at an intensity of 83 W·sec / m². 2 Plasma treatment was performed using Ar gas. The plasma treatment intensity was calculated using the following formula. Plasma treatment intensity = power density [W / m²] 2 ] × Processing time [sec] ·Power density [W / m 2 ] = Input power [W] / Cathode area [m²] 2 ] Processing time [sec] = Electrode MD width [m] / Processing speed [m / sec]

[0128] Next, a coating agent, prepared by mixing liquid A and liquid B in a mass ratio of 6:4, was applied to the gas barrier layer 20 using the gravure coating method and dried to form a coating layer 30 with a thickness of 0.4 μm. Solution A: Hydrolyzed solution with a solid content of 3 wt% (SiO2 equivalent) obtained by adding 89.6 g of hydrochloric acid (0.1 N) to 10.4 g of tetraethoxysilane and stirring for 30 minutes. Solution B: 3 wt% water / isopropyl alcohol solution of polyvinyl alcohol (water:isopropyl alcohol weight ratio 90:10) Based on the above, a gas barrier film according to Example 2-1 was prepared.

[0129] The polarity component of the surface free energy of the second surface after the completion of the gas barrier film was calculated based on the contact angle values ​​of water and diiodomethane measured using a tactile meter (DMs-401, Kyowa Interface Science Co., Ltd.). The contact angle was measured 1 second after application, with an appropriate amount of 2.5 μl of each liquid. The commonly used Owens-Wendt-Rabel-Kaelble (WORK, Kaelble-Uy) method was used to calculate the surface free energy (= polarity component value + dispersion component value) and the values ​​of each component. The polarity component of the surface free energy of the second surface was 0.1 mJ / m 2 That was the case.

[0130] (Example 2-2) The copolymer layer on the second side is formed from a copolymer of propylene and ethylene, and a magnetron sputtering discharge apparatus (MF treatment apparatus) powered by an MF power supply is used to process the material at an intensity of 331 W·sec / m². 2 Except for performing plasma treatment using O2 gas, the gas barrier film according to Example 2-2 was fabricated using the same procedure as in Example 2-1. The polarity component value of the surface free energy of the second surface was 0.2 mJ / m 2 That was the case.

[0131] (Examples 2-3) Plasma treatment intensity: 993 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 2-3 was prepared using the same procedure as in Example 2-2. The polarity component value of the surface free energy of the second surface was 0.3 mJ / m 2 That was the case.

[0132] (Examples 2-4) The copolymer layer on the second surface is formed from a copolymer of propylene and ethylene, and the plasma treatment intensity is set to 300 W·sec / m². 2 Except for the aforementioned point, the gas barrier film according to Example 2-4 was prepared using the same procedure as in Example 2-1. The polarity component value of the surface free energy of the second surface was 0.4 mJ / m 2 That was the case.

[0133] (Examples 2-5) Plasma treatment intensity: 500 W·sec / m 2 Except for the aforementioned point, the gas barrier film according to Example 2-5 was prepared using the same procedure as in Example 2-4. The polarity component value of the surface free energy of the second surface was 1.0 mJ / m 2 That was the case.

[0134] (Examples 2-6) The copolymer layer on the second side is formed from a copolymer of propylene and ethylene, and treated with O2 gas at an intensity of 100 W·sec / m². 2 Except for the plasma treatment performed, the gas barrier film according to Example 2-6 was prepared using the same procedure as in Example 2-1. The polarity component value of the surface free energy of the second surface was 1.3 mJ / m 2 That was the case.

[0135] (Examples 2-7) Plasma treatment intensity: 500 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Example 2-7 was prepared using the same procedure as in Example 2-1. The polarity component value of the surface free energy of the second surface was 1.5 mJ / m 2 That was the case.

[0136] (Comparative Example 2-1) A gas barrier film according to Comparative Example 2-1 was prepared using the same procedure as in Example 2-1, except that plasma treatment was not performed on the second surface. The polarity component value of the surface free energy of the second surface was 0.0 mJ / m 2 That was the case.

[0137] (Comparative Example 2-2) A gas barrier film according to Comparative Example 2-2 was prepared using the same procedure as in Example 2-2, except that plasma treatment was not performed on the second surface. The polarity component value of the surface free energy of the second surface was 0.0 mJ / m 2 That was the case.

[0138] (Comparative Example 2-3) A gas barrier film according to Comparative Example 2-3 was prepared using the same procedure as in Comparative Example 2-1, except that the thickness of the polypropylene homopolymer layer was 19 μm and no copolymer layer was provided on the second surface. The polar component value of the surface free energy of the second surface was 0.0 mJ / m 2 That was the case.

[0139] (Comparative Example 2-4) A gas barrier film according to Comparative Example 2-4 was prepared using the same procedure as in Example 2-3, except that the thickness of the polypropylene homopolymer layer was 19 μm and no copolymer layer was provided on the second surface. The polar component value of the surface free energy of the second surface was 0.3 mJ / m 2 That was the case.

[0140] (Comparative Example 2-5) The polypropylene homopolymer layer was set to a thickness of 19 μm, and no copolymer layer was provided on the second surface. The plasma treatment intensity was set to 1325 W·sec / m². 2 Except for the aforementioned point, a gas barrier film according to Comparative Example 2-5 was prepared using the same procedure as in Example 2-2. The polarity component value of the surface free energy of the second surface was 0.4 mJ / m 2 That was the case.

[0141] (Comparative Example 2-6) The polypropylene homopolymer layer was 19 μm thick, and no copolymer layer was provided on the second surface. The treatment intensity was 83 W·sec / m using O2 gas. 2 A gas barrier film according to Comparative Example 2-6 was prepared using the same procedure as in Example 2-1, except that plasma treatment was performed. The polar component value of the surface free energy of the second surface was 1.2 mJ / m 2 That was the case.

[0142] (Comparative Example 2-7) Plasma treatment intensity: 300 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Comparative Example 2-7 was prepared using the same procedure as in Comparative Example 2-6. The polar component value of the surface free energy of the second surface was 2.0 mJ / m 2 That was the case.

[0143] (Comparative Example 2-8) Plasma treatment intensity: 500 W·sec / m 2 Except for the points mentioned above, the gas barrier film according to Comparative Example 2-8 was prepared using the same procedure as in Comparative Example 2-7. The polarity component value of the surface free energy of the second surface was 3.8 mJ / m 2 That was the case.

[0144] The following evaluations were performed on the gas barrier films according to the examples and comparative examples. (Evaluation of adhesion on the second surface) A heat-sealed layer was created on the second surface of the gas barrier film for each example by laminating a 70 μm thick unstretched polypropylene film (Toray Industries ZK207) using a two-component curing polyurethane adhesive. Furthermore, a surface layer was created on the coating layer 30 by laminating a 20 μm thick stretched polypropylene film (Mitsui Chemicals Tohcello U1) using a two-component curing polyurethane adhesive, thereby producing a barrier laminate for each example. Test specimens were cut from each example of barrier laminate according to JIS K 6854-2 for 180° peel and JIS K 6854-3 for T-shaped peel, and the peel strength between the substrate layer and the heat seal layer was measured using an Orientec Tensilon universal tester RTC-1250. Two types of measurements were performed: T-shaped peel and 180° peel. In both T-shaped and 180° peel tests, if the peel strength was 1 N / 15 mm or higher, it can be said that there is sufficient adhesion on the second surface.

[0145] (Blocking evaluation) Two 70mm square samples were cut from each example's gas barrier film and stacked. Using a Tester Industries CO-201 permanent strain testing machine (blocking tester), the stacked samples were subjected to a pressure of 200kg and stored at 50°C for two days. Subsequently, the peel strength between the upper and lower samples was measured using a Shimadzu Autograph in accordance with JIS K 6854-2 and JIS K 6854-3. Specifically, in the blocking evaluation, a peel test was performed between the second surface of the substrate of the upper sample and the coating layer of the lower sample. Two types of measurements were performed: T-shaped peeling and 180° peeling. Blocking was defined as occurring if a peel strength of 0.1 N / 15 mm or higher was observed in either measurement. The results are shown in Table 2.

[0146] [Table 2]

[0147] In all the examples shown in Table 2, the peel strength in the adhesion evaluation of the second surface was 1 N / 15 mm or higher for both the T-shape and 180° configurations, confirming that the heat seal layer provided on the second surface side was sufficiently adhered to the substrate layer. Furthermore, the polar component value of the surface free energy of the second surface was 1.3 mJ / m 2 In Examples 2-1 to 2-5, where the values ​​were less than 0.1 N / 15 mm, the peel strength in the blocking evaluation was less than 0.1 N / 15 mm in both the T-shape and 180° configurations, indicating that blocking was sufficiently suppressed.

[0148] On the other hand, in Comparative Examples 2-1 to 2-3, the peel strength values ​​in the adhesion evaluation of the second surface were low, indicating insufficient adhesion between the substrate layer and the heat seal layer. In Comparative Examples 2-4 to 2-8, where the second surface was a homopolymer layer, a zipping phenomenon was observed in the 180° peel test during the adhesion evaluation of the second surface, where the peel strength repeatedly fluctuated between low and high values. As an example, Figure 4 shows a graph of the measurement chart for the 180° peel test in Comparative Example 2-5, where the zipping phenomenon occurred.

[0149] Here, the zipping phenomenon is a phenomenon in which the peel strength changes intermittently as the peeling surface does not peel smoothly, but rather alternates between the progression and stopping of peeling. Furthermore, the zipping phenomenon is thought to be more likely to occur when the adhesion strength is not constant in the direction in which peeling progresses within the adhesive surface of the two layers, and there is variation in adhesion strength from place to place. In a barrier laminate with variations in adhesion strength between the base layer and the heat seal layer, there is a possibility that bag rupture will occur from areas with weak adhesion strength. Therefore, by checking for the presence or absence of the zipping phenomenon, it is possible to confirm the uniformity of the adhesion and bag rupture strength of the second surface of the barrier laminate.

[0150] In Comparative Examples 2-4 to 2-8 in Table 2, the zipping phenomenon was observed, and therefore the minimum and maximum peel strength values ​​are shown in the 180° peel measurement results column for the adhesion evaluation of the second surface. From the results of Comparative Examples 2-4 to 2-8, it can be determined that the zipping phenomenon is occurring when the difference between the maximum and minimum peel strength values ​​is 0.3 N / 15 mm or more. In Examples 2-1 to 2-7 and Comparative Examples 2-1 to 2-3, the difference between the maximum and minimum peel strength values ​​was small, and the zipping phenomenon was not observed during the test, so the average value of the measured values ​​is shown as the peel strength in Table 2. Based on the evaluation results shown in Table 2, it is considered that the zipping phenomenon is unlikely to occur when the difference between the maximum and minimum peel strength values ​​in 180° peeling is less than 0.3 N / 15 mm.

[0151] Furthermore, in Comparative Example 2-8, the polar component value of the surface free energy of the second surface was 1.3 mJ / m 2 That concludes the report, and blocking also occurred.

[0152] Although one embodiment of the present invention and its examples have been described above, the specific configuration is not limited to this embodiment, and modifications and combinations of the configuration that do not depart from the spirit of the present invention are also included. [Explanation of Symbols]

[0153] 1. Gas barrier film 10 Base material layer 10a Front page 10b Second side 20 Gas barrier layer 30 Covering layer 40 Heat seal layer 60 Surface layer 61 Printing layer 101, 102 Barrier laminate

Claims

1. A substrate layer having a layer mainly composed of polypropylene or polyethylene, and a copolymer layer composed of a copolymer of polypropylene and polyethylene, or a copolymer of propylene, ethylene and 1-butene, A gas barrier layer formed on the first surface of the substrate layer opposite to the second surface on which the copolymer layer is provided, A heat-seal layer, which is an unstretched film mainly composed of polypropylene or polyethylene, is bonded to the second surface by dry lamination using a two-component curing polyurethane adhesive. Equipped with, The peel strength between the second surface of the substrate layer and the heat seal layer is, In 180° peeling according to JIS K 6854-2, the N / 15mm is 1.0 N / 15mm or more and 7.0 N / 15mm or less. In T-shaped peeling according to JIS K 6854-3, the thickness is 1.0 N / 15 mm or more and 4.0 mm / 15 mm or less. The polarity component value of the surface free energy of the second surface is 0.1 mJ / m ２ 1.6mJ / m or more ２ The following is: Gas barrier film.

2. The polarity component value of the surface free energy of the second surface is 0.1 mJ / m ２ 1.3 mJ / m or more ２ Less than, The gas barrier film according to claim 1.

3. The gas barrier layer contains at least one of silicon oxide, carbon-containing silicon oxide, silicon nitride, metallic aluminum, and aluminum oxide. The gas barrier film according to claim 1 or 2.

4. The base layer is further provided with a layer on the first surface which is made of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and ethylene vinyl alcohol copolymer. The gas barrier film according to claim 1 or 2.

5. The gas barrier layer further comprises a coating layer formed on the aforementioned gas barrier layer, The coating layer contains one of the following: a metal alkoxide, a hydrolysate of a metal alkoxide, a water-soluble polymer, a polycarboxylic acid polymer, a polyvalent metal compound, or a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid polymer and a polyvalent metal compound. The gas barrier film according to claim 1 or 2.

6. The undercoat layer is further provided between the first surface and the gas barrier layer, The undercoat layer comprises at least one of a thermosetting resin, a thermoplastic resin, an ultraviolet curing resin, and an electron beam curing resin. The gas barrier film according to claim 1 or 2.

7. The peel strength between the second surface of the substrate layer and the heat seal layer is, In 180° peeling according to JIS K 6854-2, the N / 15mm is between 2.0 N / 15mm and 7.0 N / 15mm. The gas barrier film according to claim 1 or 2.

8. The difference between the maximum and minimum values ​​of the peeling strength in the aforementioned 180° peeling is less than 0.3 N / 15 mm. The gas barrier film according to claim 1 or 2.

9. A gas barrier film according to claim 1 or 2, The main component is the same as that of the base layer, which is mainly composed of polypropylene or polyethylene, and comprises a surface layer bonded to the gas barrier film. Barrier laminate.

10. The surface layer is bonded to the gas barrier film with an adhesive, The barrier laminate according to claim 9.

11. The surface layer has a printed layer on at least one surface. The barrier laminate according to claim 9.

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