Gas barrier film and barrier laminate

Abstract

To provide a gas barrier film and a barrier laminate excellent in adhesion at a face with no gas barrier layer formed and easy to mono-materialize.SOLUTION: A gas barrier film includes: a substrate layer having polypropylene or polyethylene as a main constituent; a gas barrier layer formed on a first side of the substrate layer; and a heat seal layer formed on a second side opposite to the first side and having polypropylene or polyethylene as a main constituent. A peel strength between the substrate layer and the heat seal layer is 1.0 N / 15 mm to 7.0 N / 15 mm at 180° peeling in accordance with JIS K 6854-2, and 1.0 N / 15 mm to 4.0 mm / 15 mm at T-shaped peeling in accordance with JIS K 6854-3.SELECTED DRAWING: Figure 2

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 to 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, the contents of which are incorporated 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 the blocking of various gases, such as the packaging of precision electronic components, electronics 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 resource recovery of plastic materials. This is also the case for gas barrier films that have been improved in performance by combining various different materials, and there is a growing demand for them to be made of a single material.

[0004] To achieve a single material structure, 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 substrate 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 of a multilayer laminate film, adhesion to an adhesive or an ink layer is required on the surface of the multilayer laminate film where the gas barrier layer is not formed. In Patent Document 1, although attention is paid to the adhesion between the base material and the aluminum oxide vapor deposition film, no attention is paid to the surface on the side where the vapor deposition film is not formed.

[0007] In addition, as an evaluation method for adhesion in a multilayer laminate film, a peel test conforming to JIS K 6854-2 and JIS K 6854-3 is widely used. In this peel test, a phenomenon called "dipping" may occur in which peeling does not proceed smoothly and the progress and stop of peeling are alternately repeated. When dipping occurs in a peel test (also called a peel test), the adhesion of the multilayer laminate film may not be correctly evaluated. As a result, it becomes difficult to determine whether the manufactured film satisfies the required characteristics.

[0008] In view of the above circumstances, an object of the present invention is to provide a gas barrier film and a barrier laminate having good adhesion on the surface where the gas barrier layer is not formed and being easily made into a single material.

Means for Solving the Problems

[0009] The present invention has the following aspects.

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

[0011] [2] The polar component value of the surface free energy of the second surface on the side opposite to the first surface is 0.1 mJ / m 2 or more, the gas barrier film according to [1].

[0012] [3] The second surface on the side opposite to the first surface is composed of a copolymer, and the polar component value of the surface free energy is 0.1 mJ / m 2 or more, the gas barrier film according to [1].

[0013] [4] The polar component value of the surface free energy of the second surface is less than 1.3 mJ / m 2 , the gas barrier film according to any one of [1] to [3].

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

[0015] [6] The first surface is made of any one 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 any one of [1] to [5].

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

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

[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 180° peel conforming to JIS K 6854-2.

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

[0019]

[11] A barrier laminate comprising the gas barrier film according to any one of [1] to

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

[0020]

[12] The barrier laminate according to

[11] , further comprising a surface layer having the same main component as the base material layer and joined to the gas barrier film.

[0021]

[13] The barrier laminate according to

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

[0022]

[14] The barrier laminate according to

[12] or

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

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

[0024] [A2] The polar component value of the surface free energy of the second surface is 1.3 mJ / m 2 The gas barrier film according to [A1], wherein the polar component value is less than

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

[0026] [A4] The first surface is made of any one 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, and the gas barrier film according to any one of [A1] to [A3].

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

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

[0029] [A7] A barrier laminate including the gas barrier film according to any one of [A1] to [A6], and a heat seal layer having the same main component as the base material layer and joined to the gas barrier film.

[0030] [A8] The barrier laminate according to [A7], further comprising a surface layer having the same main component as the base material layer and joined to the gas barrier film.

[0031] [A9] The barrier laminate according to [A8], wherein at least one of the heat seal layer and the surface layer is joined 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] As another aspect, the present invention has the following embodiments. [B1] A gas barrier film comprising a base material layer mainly composed of polypropylene or polyethylene, and a gas barrier layer formed on the first surface side of the base material layer. In this gas barrier film, the second surface opposite to the first surface is composed of a copolymer, and the polar component value of the surface free energy is 0.1 mJ / m 2 less than.

[0034] [B2] The gas barrier film according to [B1], wherein the polar component value of the surface free energy of the second surface is less than 1.3 mJ / m 2 .

[0035] [B3] The gas barrier film according to [B1] or [B2], wherein the gas barrier layer contains at least one of silicon oxide, silicon oxide containing carbon, silicon nitride, metal 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 any one of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and ethylene vinyl alcohol copolymer.

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

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

[0039] [B7] A barrier laminate comprising the gas barrier film according to any one of [B1] to [B6], and a heat seal layer having the same main component as the base material layer and joined to the gas barrier film.

[0040] [B8] Further comprising a surface layer having the same main component as the base material layer and joined to the gas barrier film, the barrier laminate according to [B7].

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

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

[0043] According to the present invention, it is possible to provide a gas barrier film and a barrier laminate having good adhesion on the surface where the gas barrier layer is not formed and being easily made into a single material. [Brief Description of the Drawings]

[0044]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

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

[0046] The base material layer 10 is a resin film mainly composed of polypropylene or polyethylene. The base material layer 10 may be either an unstretched film or a stretched film. When using a stretched film, there is no particular limitation on the stretching ratio. Also, there is no particular limitation on the thickness of the base material layer 10. The base material layer 10 can be a single-layer film or a multilayer film formed by laminating films with different properties in consideration of applications such as packaging materials. Considering the processability when forming the gas barrier layer 20 and the coating layer 30, etc., the thickness of the base material layer 10 is preferably in the range of 3 to 200 μm, particularly preferably 6 to 50 μm in practical terms. Also, the form of the base material layer 10 may be a long strip or a sheet material cut into a predetermined size, but a long base material can be preferably used. The length in the longitudinal direction of the long base material layer 10 is not particularly limited, but for example, a long film of 10 m or more is preferably used. Note that since there is no upper limit on the length, for example, it may be about 10 km, and in this case, transportation and storage can be efficiently carried out by winding it into a roll.

[0047] The "main component" of the base material layer 10 means the substance with the largest mass among the substances constituting the base material layer 10. In this embodiment, the "main component" of each component means the substance with the largest mass among the substances constituting each component. When the main component of the base material layer 10 is polypropylene, the main component of the base material layer 10 is not limited to a resin obtained by polymerizing only propylene, and a resin containing substances other than propylene can be used. For example, a copolymer obtained by copolymerizing polyethylene such as HDPE (high-density polyethylene), MDPE (medium-density polyethylene), LDPE (low-density polyethylene), LLDPE (linear low-density polyethylene) at a ratio of 0.1 to several tens of % with respect to propylene, or a polymer obtained by copolymerizing an α-olefin resin such as 1-butene or / and a rubber component such as an elastomer at a ratio of 0.1 to several tens of % with respect to propylene or ethylene can also be used. Further, instead of copolymerization, a layer in which a plurality of types of resins are mixed and dispersed can also be used.

[0048] When the main component of the base material layer 10 is polyethylene, the polyethylene resin can be selected from any one or a plurality of HDPE, LDPE, MDPE, and LLDPE. Further, a copolymer or polymer obtained by copolymerizing an α-olefin resin such as 1-butene or / and a rubber component such as an elastomer at a ratio of 0.1 to several tens of % with respect to ethylene can also be used.

[0049] The base material layer 10 may be a multilayer film in which films having different properties are laminated. In this case, in the base material layer 10, a layer made of any one 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 may be provided on the surface that becomes the first surface 10a. When the base material layer 10 is multilayered, the base material layer 10 may have a layer mainly composed of polypropylene or polyethylene and a layer not containing the main component. For example, if the layer constituting the first surface 10a is a layer composed only of PVA (polyvinyl alcohol) or EVOH (ethylene vinyl alcohol copolymer), the barrier property of the gas barrier film 1 can be improved. The base material layer 10 having a plurality of layers (also referred to as a multilayer base material) can be formed by laminating a plurality of films using an adhesive or coextrusion using a plurality of screws. In the multilayer base material formed by coextrusion, the boundary of each layer cannot be clearly confirmed even when observed with an optical microscope, but the boundary of each layer can be confirmed by observing the cross section with a transmission electron microscope (TEM) after appropriate staining.

[0050] The base material layer 10 may contain additives that are not resin components. The additives can be appropriately selected from various known additives. Examples of the additives include an anti-blocking agent (AB agent), a heat stabilizer, a weather stabilizer, an ultraviolet absorber, a lubricant, a slip agent, a nucleating agent, an antistatic agent, an anti-fogging agent, a pigment, and a dye. The AB agent may be either organic or inorganic. Any one of these additives may be used alone, or two or more of them may be used in combination. Among the above, the lubricant and the slip agent are mentioned as preferable additives from the viewpoint of processability. The content of the additive in the base material layer 10 can be appropriately adjusted within a range that does not hinder the effect of the gas barrier film in the present embodiment.

[0051] The gas barrier layer 20 is a layer of a single substance or a mixture mainly composed of any one of silicon oxide, silicon oxide containing carbon, silicon nitride, metal aluminum, and aluminum oxide, and exhibits barrier properties against predetermined gases such as oxygen and water vapor. In the gas barrier layer 20, there may be a plurality of main components with the largest mass. The gas barrier layer 20 may be either transparent or opaque.

[0052] The thickness of the gas barrier layer 20 varies depending on the type, composition, and film formation method of the components used, but generally can be appropriately set 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 not be sufficient, and the function as a gas barrier layer may not be fully exhibited. If the thickness of the gas barrier layer 20 exceeds 300 nm, cracks may occur in the gas barrier layer 20 due to external factors such as bending and stretching after film formation, resulting in loss of barrier properties. The thickness of the gas barrier layer 20 is more preferably within the range of 6 to 150 nm.

[0053] There is no limitation on the method for forming the gas barrier layer 20. For example, vacuum evaporation, plasma-activated evaporation, ion beam evaporation, ion plating, sputtering, and plasma chemical vapor deposition (CVD) can be used. By combining methods such as plasma assist method and ion beam assist method, the gas barrier layer 20 can be formed densely to improve the 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 can have an arbitrary configuration and can also be omitted. The coating layer 30 can use a coating layer such as a thermoplastic resin, a thermosetting resin, an ultraviolet curable resin, a metal alkoxide or its hydrolyzate, a water-soluble polymer, a polycarboxylic acid-based polymer, a polyvalent metal compound, or a polyvalent metal salt of a carboxylic acid which is a reaction product of a polycarboxylic acid-based polymer and a polyvalent metal compound. In particular, a coating layer containing a metal alkoxide and a water-soluble polymer, which is excellent in oxygen barrier properties, is preferable. This coating layer is formed using a coating agent mainly composed of an aqueous solution or a water / alcohol mixed solution containing a water-soluble polymer and one or more metal alkoxides or their hydrolyzates. For example, a coating agent is prepared by mixing a water-soluble polymer dissolved in an aqueous (water or water / alcohol mixed) solvent with a metal alkoxide that has been directly treated or hydrolyzed in advance. After applying this coating agent onto the gas barrier layer 20 and drying, the coating layer 30 can be formed.

[0055] Each component included in the coating agent for forming the coating layer 30 will be described in more detail. Examples of the water-soluble polymer used in the coating agent include PVA, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. In particular, it is preferable to use PVA because excellent gas barrier properties can be obtained. PVA is generally obtained by saponifying polyvinyl acetate. As PVA, either so-called partially saponified PVA in which several tens of % of acetate groups remain or completely saponified PVA in which only several % of acetate groups remain can be used. PVA in the middle of both may also be used.

[0056] The metal alkoxide used in the coating agent is a compound represented by the general formula, M(OR)n (M: metal such as Si, Al; R: alkyl group such as CH3, C2H5). Specifically, examples include tetraethoxysilane [Si(OC2H5)4], triisopropoxyaluminum Al[OCH(CH3)2]3, etc. Examples of the silane coupling agent include compounds having an epoxy group such as 3-glycidoxypropyltrimethoxysilane, compounds having an amino group such as 3-aminopropyltrimethoxysilane, compounds having a mercapto group such as 3-mercaptopropyltrimethoxysilane, compounds having an isocyanate group such as 3-isocyanatopropyltriethoxysilane, and tris-(3-trimethoxysilylpropyl)isocyanurate, etc.

[0057] A polycarboxylic acid polymer is a polymer having two or more carboxy groups in the molecule. Examples of the polycarboxylic acid polymer include (co)polymers of ethylenically unsaturated carboxylic acids; copolymers of ethylenically unsaturated carboxylic acids and other ethylenically unsaturated monomers; and acidic polysaccharides having a carboxyl group in the molecule such as alginic acid, carboxymethyl cellulose, and pectin. Examples of the ethylenically unsaturated carboxylic acid include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the ethylenically unsaturated monomer copolymerizable with the ethylenically unsaturated carboxylic acid include vinyl esters of saturated carboxylic acids such as ethylene, propylene, and vinyl acetate, alkyl acrylates, alkyl methacrylates, alkyl itaconates, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. These polycarboxylic acid polymers may be used alone or in combination of two or more.

[0058] From the viewpoint of gas barrier properties, among the above-described components, a polymer containing a structural unit 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 is preferable, and a polymer containing a structural unit derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is particularly preferable. In the above polymer, the proportion of the structural unit 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, more preferably 90 mol% or more (where the total of all structural units constituting the polymer is 100 mol%). This polymer may be a homopolymer or a copolymer. When the polymer is a copolymer containing other structural units in addition to the above structural units, examples of the 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, more preferably 5,000 to 1,000,000. When the number average molecular weight is less than 2,000, depending on the application, the water resistance of the gas barrier film may not be sufficient, and the gas barrier property and transparency may deteriorate due to moisture, or whitening may occur. On the other hand, when the number average molecular weight exceeds 10,000,000, the viscosity of the coating agent may increase, and the coatability may be impaired. In the present embodiment, the number average molecular weight is the number average molecular weight in terms of polystyrene determined by gel permeation chromatography (GPC).

[0060] Various additives can be added to the coating agent mainly composed of the polycarboxylic acid polymer, 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 the barrier performance is not impaired.

[0061] The solvent used for the coating agent mainly composed of the polycarboxylic acid polymer is preferably an aqueous medium. Examples of the aqueous medium include water, water-soluble or hydrophilic organic solvents, or mixtures thereof. The aqueous medium usually contains water or water as the main component. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more. Examples of the 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 reacts with the carboxyl groups 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 alone or in combination of two or more. From the viewpoint of the oxygen barrier property of the oxygen barrier film, zinc oxide particles among the above are preferable. Zinc oxide is an inorganic material having ultraviolet absorption ability. The average particle diameter of the zinc oxide particles is not particularly limited, but from the viewpoints of gas barrier property, transparency, and coating suitability, the average particle diameter is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0063] When forming a film by applying and drying a coating agent containing a polyvalent metal compound as a main component, if necessary, various additives may be contained in the coating agent in addition to zinc oxide particles, as long as the effects of this embodiment are not impaired. Examples of such additives include resins that are soluble or dispersible in the solvent used for the coating agent, dispersants that are soluble or dispersible in the solvent, surfactants, softeners, stabilizers, film-forming agents, and thickeners. Among these, it is preferable to contain a resin that is soluble or dispersible in the solvent used for the coating agent. This improves the coatability and film-forming property of the coating agent. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenol resins, amino resins, fluorine resins, epoxy resins, and isocyanate resins. Also, it is preferable to contain a dispersant that is soluble or dispersible in the solvent used for the coating agent. This improves the dispersibility of the polyvalent metal compound. As the dispersant, anionic surfactants or nonionic surfactants can be used. Examples of such surfactants include (poly)carboxylates, alkyl sulfate esters, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, aromatic phosphate esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenol ethers, polyoxyethylene alkyl esters, alkyl allyl sulfate esters, 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 alkyl amines. These surfactants may be used alone or in combination of two or more.When an additive is included in a coating agent containing a polyvalent metal compound as a main component, 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 more preferably in the range of 50:50 to 98:2.

[0064] Examples of the solvent used for the coating agent containing a polyvalent metal compound as a main component 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 alone or in combination of two or more. Among these, from the viewpoint of coatability, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferable. From the viewpoint of productivity, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferable.

[0065] When forming a film of a polyvalent metal compound after applying and drying a coating agent containing a polycarboxylic acid-based polymer as a main component to form a film, a part of the carboxy groups of the polycarboxylic acid-based polymer may be previously neutralized with a basic compound. By previously neutralizing a part of the carboxy groups possessed by the polycarboxylic acid-based polymer, the water resistance and heat resistance of the film made of the polycarboxylic acid-based polymer can be further improved. As the basic compound, at least one basic compound selected from the group consisting of the above-described polyvalent metal compounds, monovalent metal compounds, and ammonia is preferable. Examples of the monovalent metal compound include sodium hydroxide and potassium hydroxide.

[0066] When forming a film by applying and drying a coating agent obtained by mixing a polycarboxylic acid-based polymer and a polyvalent metal compound, a coating agent is prepared by mixing a polycarboxylic acid-based polymer, a polyvalent metal compound, water or alcohols as a solvent, a resin or a dispersant that can be dissolved or dispersed in the solvent, and, if necessary, an additive. By applying and drying such a coating agent by a known coating method, the coating layer 30 can also be formed.

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

[0068] The thickness of the coating layer 30 varies depending on the composition of the coating agent used, the coating conditions, etc., and is not particularly limited. However, when the film thickness after drying 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. When the film thickness after drying exceeds 50 μm, cracks are likely to occur in the coating layer 30. Therefore, a suitable thickness of the coating layer 30 is, for example, in the range of 0.01 to 50 μm, and an optimum thickness of 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 configuration can be widely used for applications constituting a part of various laminated bodies having barrier properties (hereinafter sometimes collectively referred to as "barrier laminated bodies"). In this case, various layers are provided on the second surface 10b of the base material layer 10 and on the gas barrier layer 20 or the 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 to the layer provided on the second surface 10b is required.

[0070] The inventors conducted various studies to improve the adhesion to 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 to 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 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 state with multiple sheets, a phenomenon called blocking may occur, where 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., reducing the manufacturing efficiency of the barrier laminate using the gas barrier film 1. In the inventors' studies, 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. Among the above-described methods, plasma treatment is particularly preferable from the viewpoint of ease of adjusting the polar component value of the surface free energy. Argon or oxygen can be used for the plasma treatment.

[0074] In the gas barrier film 1 according to the present embodiment, it is only necessary that the polar component value of the surface free energy of the second surface 10b satisfies a predetermined condition, and the material of the second surface is not particularly limited. Therefore, if the main component of the base material layer 10 is polyethylene or polypropylene, the second surface 10b may be constituted by a layer containing neither polyethylene nor polypropylene.

[0075] The gas barrier film 1 of the present embodiment having the above configuration exhibits high gas barrier properties. Further, since the base material layer 10 contains polyethylene or polypropylene as a main component, it is easy to set the ratio of polyethylene or polypropylene in the gas barrier film 1 to 90% by mass or more. That is, the gas barrier film 1 can be easily made into a monomer material with high recyclability, and environmental measures can be easily taken.

[0076] A configuration example of a barrier laminate using the gas barrier film 1 will be described below. The barrier laminate 101 shown in FIG. 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. When two or one folded barrier laminate 101 is heat-sealed at the peripheral portion with the heat seal layers 40 facing each other, a packaging material such as a pouch made of the barrier laminate 101 can be formed, and a package in which the contained contents are sealed can be obtained.

[0077] As the material of the heat seal layer 40, polypropylene or polyethylene can be used, and it can be single-layer or multi-layer. By making the main component of the heat seal layer 40 the same as that of the base material layer 10, the barrier laminate 101 can be made into a monomer material. In this case, the same film as the base material 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 (the degree of +- polarization within the molecule). For this reason, the heat-sealing layer mainly composed of polypropylene or polyethylene is difficult to bond to the base material layer 10 by either extrusion lamination or dry lamination. However, in the gas barrier film 1, since the polar component of the surface free energy of the second surface 10b is 0.1 mJ / m 2 or more, the bondability with the heat-sealing layer is significantly improved. Particularly in dry lamination, when the polar component of the surface free energy of the second surface 10b is 0.1 mJ / m 2 or more, the adhesive uniformly wets and spreads, and an interaction occurs between the molecules constituting the second surface 10b and the adhesive molecules. As a result, the resin film serving as the heat-sealing layer is bonded with a high adhesive strength of 1 N / 15 mm or more as the peel strength in a measurement conforming to, for example, JIS K 6854-2 (180° peel) or JIS K 6854-3 (T-peel). In addition, the inventors have found that in the gas barrier film 1 provided with the heat-sealing layer 40 according to the present embodiment, the peel strength between the base material layer 10 and the heat-sealing layer 40 is 2.0 N / 15 mm or more in 180° peel conforming to JIS K 6854-2, so that the adhesion of the second surface 10b of the base material layer 10 is good and the occurrence of dipping in the peel test can be suppressed.

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

[0080] The barrier laminate 102 shown in FIG. 3 has a structure in which a surface layer 60 is joined above the gas barrier layer 20 of the barrier laminate 101 via an adhesive layer 50. The surface layer 60 may have the same main component as the base material layer 10. The joining method of the surface layer 60 may be the same as the joining method of the heat seal layer 40 described above. Note that at least one of the heat seal layer 40 and the surface layer 60 may be joined to the gas barrier film 1 with an adhesive. The surface layer 60 has a printing layer 61 on one surface, and is joined in a state where the printing layer 61 faces the gas barrier layer 20. Note that the printing layer 61 may be provided on the surface of the surface layer 60 opposite to the surface facing the gas barrier layer 20. When forming a packaging material using the barrier laminate 101, the gas barrier layer 20 constitutes the outer surface of the packaging material. However, in the packaging material formed using the 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 made to have desired contents suitable for the application and the like. Also, the printing layer 61 can easily impart a desired appearance, display, etc. Furthermore, by joining the printing layer 61 in a state where it faces the gas barrier layer 20, the user of the packaging material does not touch the printing layer 61, and deterioration of the printing layer accompanying the use of the packaging material can be suppressed.

[0081] The configuration of the barrier laminate using the gas barrier film 1 is not limited to the above-described example. For example, the arrangement of the surface layer 60 and the heat seal layer 40 may be reversed, or in the case where the barrier laminate has more layers, the heat seal layer 40 may be provided on both surfaces of the gas barrier film 1. Also, 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 the present embodiment, an undercoat layer (not shown) may be provided between the first surface 10a and the gas barrier layer 20. The undercoat layer can enhance the adhesion between the base material layer 10 and the gas barrier layer 20 to prevent the occurrence of delamination of the gas barrier layer 20, or protect the first surface 10a from mechanical damage such as scratches and abrasions in the conveying process before the formation of the gas barrier layer. The material of the undercoat layer is not particularly limited, and examples thereof include thermosetting resins, thermoplastic resins, ultraviolet curable resins, and electron beam curable resins.

[0083] Examples of the thermosetting resin for forming the undercoat layer include thermosetting urethane resins composed of acrylic polyol and isocyanate prepolymer, phenol resins, urea melamine resins, epoxy resins, unsaturated polyester resins, and silicone resins. Among them, an undercoat layer formed of a composite of an acrylic polyol containing an OH group and an isocyanate compound having at least two or more NCO groups in the molecule can significantly enhance the adhesion between the base material layer 10 and the gas barrier layer 20.

[0084] Acrylic polyol is a polymer compound obtained by polymerizing a (meth)acrylic acid derivative monomer, or a polymer compound obtained by copolymerizing a (meth)acrylic acid derivative monomer and other monomers, etc., which has OH groups at the terminal and side chains and reacts with the NCO group of the isocyanate compound. The (meth)acrylic acid derivative monomer has OH groups at the terminal and side chains. Examples of the (meth)acrylic acid derivative monomer include hydroxyethyl (meth)acrylate and hydroxybutyl (meth)acrylate.

[0085] The above "other monomers" are copolymerizable with (meth)acrylic acid derivative monomers having OH groups at both ends and side chains. Examples of "other monomers" include (meth)acrylic acid derivative monomers having an alkyl group in the side chain such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, etc., (meth)acrylic acid derivative monomers having a COOH group in the side chain such as (meth)acrylic acid, (meth)acrylic acid derivative monomers having an aromatic ring or a cyclic structure in the side chain such as benzyl (meth)acrylate, cyclohexyl (meth)acrylate, etc. Other than (meth)acrylic acid derivative monomers, styrene monomers, cyclohexyl maleimide monomers, phenyl maleimide monomers, etc. are considered. The "other monomers" themselves may have OH groups at both ends 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 the side chain such as (meth)acrylic acid. When forming the undercoat layer, by using a composite of an acrylic polyol obtained by polymerizing a monomer having a COOH group and an isocyanate-based compound, a gas barrier film having higher water vapor barrier properties can be obtained.

[0087] The acrylic polyol containing OH groups that can be used for the undercoat layer is not particularly limited, but it is desirable that the OH value is 50 mgKOH / g or more and 250 mgKOH / g or less. Here, the OH value (mgKOH / g) is an index 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 the acrylic polyol. The weight average molecular weight of the acrylic polyol is not particularly limited, but specifically, it is preferably 3000 or more and 200000 or less. In particular, it is preferably 5000 or more and 100000 or less. Further, it is more preferably 5000 or more and 40000 or less.

[0088] An isocyanate compound is one that has two or more NCO groups in its molecule. Examples of monomeric isocyanates include aromatic isocyanates such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), xylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and aliphatic isocyanates such as hexamethylene diisocyanate (HDI), bis(isocyanatomethyl)cyclohexane (H6XDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (H12MDI), etc. Also, polymers or derivatives of these monomeric isocyanates can be used. For example, there are trimeric nurate types, adduct types reacted with 1,1,1-trimethylolpropane, etc., biuret types reacted with biuret, etc.

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

[0090] As an example of the undercoat layer, it is formed by applying a solution composed of a composite of the above acrylic polyol and the above isocyanate compound and a solvent to the first surface 10a of the base material layer 10 and subjecting it to reaction curing. The equivalent ratio (NCO / OH) of the NCO group of the isocyanate compound to the OH group of the acrylic polyol is preferably 0.3 or more and 2.5 or less. The solvent used here may be any one that can dissolve the above acrylic polyol and isocyanate compound. Examples of the solvent include methyl acetate, ethyl acetate, butyl acetate, cyclohexanone, acetone, methyl ethyl ketone, dioxolane, tetrahydrofuran, etc. In practice, these solvents can be used alone or in combination of two or more.

[0091] As the thermoplastic resin for forming the undercoat layer, for example, polyols having two or more OH groups such as acrylic polyol, polyester polyol, polycarbonate polyol, polyether polyol, polycaprolactone polyol, epoxy polyol, etc., polyvinyl resins such as polyvinyl acetate and polyvinyl chloride, polyvinylidene chloride resin, polystyrene resin, polyethylene resin, polypropylene resin, polyurethane resin, etc. are appropriately selected. Further, these may be mixed at any ratio. The OH value of the polyol is not particularly limited, but it is preferably 10 mgKOH / g or more and 250 mgKOH / g or less.

[0092] As the ultraviolet curable resin or electron beam curable resin for forming the undercoat layer, as the organic polymer resin, although not particularly limited, it is desirable to contain at least a resin having an OH value in the range of 10 or more and 100 mgKOH / g or less. Also, as the organic polymer resin, although not particularly limited, it is desirable to contain at least a resin having an acid value in the range of 10 or more and 100 mgKOH / g or less. Here, the acid value (mgKOH / g) indicates the number of mg of potassium hydroxide required to neutralize free fatty acids, resin acids, etc. contained in 1 g of the sample. Also, as the organic polymer resin, it is desirable to contain at least a thermoplastic resin. When the OH value or acid value is less than 10 mgKOH / g, the chemical bonding force between the functional group and the surface of the gas barrier layer 20 becomes weak, and the adhesion to the gas barrier layer 20 tends to be low. When the OH value or acid value exceeds 100 mgKOH / g, deposits containing OH groups generated by the decomposition of the undercoat layer in durability tests such as the damp heat test tend to inhibit the adhesion between the undercoat layer and the gas barrier layer 20.

[0093] Examples of monomers that can be used in the ultraviolet curable resin or electron beam curable resin for forming the undercoat layer include monofunctional monomers such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, and N-vinylpyrrolidone, 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. Examples of oligomers that can be used in the ultraviolet curable resin or electron beam curable resin include urethane acrylate, epoxy acrylate, and polyester acrylate.

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

[0095] The undercoat layer may further contain additives as necessary in addition to the organic polymer resin. Examples of the additives include antioxidants, weathering agents, heat stabilizers, lubricants, crystal nucleating agents, ultraviolet absorbers, plasticizers, antistatic agents, colorants, fillers, surfactants, and silane coupling agents.

[0096] The thickness of the undercoat layer is preferably 0.05 μm or more and 7.0 μm or less. In particular, it is preferably 0.05 μm or more and 0.3 μm or less. If it is thinner than 0.05 μm, the adhesion between the first surface 10a of the base material layer 10 and the gas barrier layer 20 becomes insufficient. If it is thicker than 7.0 μm, the influence of internal stress becomes large, the gas barrier layer 20 cannot be properly laminated, the expression of barrier properties becomes insufficient, and furthermore, transparency and coating accuracy also become insufficient.

[0097] As a method for forming the undercoat layer, a normal coating method can be used. For example, well-known methods such as dipping method, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing method, spray coating, gravure offset method, and organic vapor deposition method can be used. As the drying method, one or a combination of two or more methods of applying heat such as hot air drying, hot roll drying, high-frequency irradiation, infrared irradiation, UV irradiation, and electron beam irradiation can be used. Further, a method of transferring a film previously coated on another resin substrate by the above forming method onto the first surface 10a using a transfer method such as adhesive transfer, thermal transfer, and UV transfer may be used.

[0098] <Second Embodiment> Next, the second embodiment according to the present invention will be described. The basic configuration is the same as that of the first embodiment. Therefore, the same components are denoted by the same reference numerals and the description thereof is omitted, and only the differences will be described.

[0099] In order to accurately evaluate the adhesion of the produced barrier laminate, it is important that no dipping occurs in the peel test conforming to JIS K 6854-2 or JIS K 6854-3. The inventor further studied a configuration capable of reducing the occurrence of dipping that occurs between the base material layer 10 and the joined layer in the barrier laminate produced using the gas barrier film 1. As a result, it was found that by configuring the second surface 10b of the base material layer 10 with a copolymer, the occurrence of dipping can be preferably reduced. Although the mechanism thereof is not completely clear, it is presumed that the formation of the layer with the copolymer improves the flexibility of the layer, contributing to the fact that fine cracks and the like that cause dipping are less likely to occur during peeling. Examples of the copolymer constituting the second surface 10b of the base material layer 10 include the copolymers described as the material of the base material layer 10 in the first embodiment. When the base material layer 10 is multilayered, the base material layer 10 may have a layer mainly composed of polypropylene or polyethylene and a layer composed of a copolymer constituting the second surface 10b. There are no particular restrictions on the types and numbers of monomers constituting the copolymer. Therefore, the copolymer may be composed of three or more types of monomers, and may not contain monomers contained in the layer to be joined, such as ethylene and propylene.

[0100] Based on the above findings obtained through research, in the gas barrier film according to the present embodiment, the second surface 10b of the base material layer 10 is composed of a copolymer, and the polar component value of the surface free energy of the second surface is 0.1 mJ / m 2 By setting it to the above, it has been successfully achieved to balance high adhesion during the production of the barrier laminate and suppression of the occurrence of dipping in the peel test.

[0101] Further, the inventors have found that in the gas barrier film 1 provided with the heat seal layer 40 according to the present embodiment, the peel strength between the base material 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 180° peel conforming to JIS K 6854-2, and 1.0 N / 15 mm or more and 4.0 mm / 15 mm or less in T-peel conforming to JIS K 6854-3. Thus, the adhesion of the second surface 10b of the base material layer 10 is good, and it is possible to suppress the occurrence of dipping in the peel test. If at least one of the peel strengths under the two measurement conditions is less than the above range, the adhesion of the second surface 10b of the base material 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 above range, there are portions where the adhesion of the two layers is excessively weak or strong, and it is considered that dipping is likely to occur due to the variation in the adhesion at the adhesion surface of the two layers.

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

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

[0104] In a vacuum apparatus, SiO was sublimated, and a gas barrier layer 20 (thickness 30 nm) made of silicon oxide (SiOx) was formed on the EVOH layer by electron beam evaporation. Furthermore, while maintaining the vacuum state, plasma treatment was performed on the second surface of the base material layer 10 using Ar gas with a plasma treatment intensity of 67 W·sec / m 2 Note that the plasma treatment intensity was calculated by the following formula. · Plasma treatment intensity = power density [W / m 2 × treatment time [sec] · Power density [W / m 2 = input power [W] / cathode area [m 2 · Treatment time [sec] = electrode MD width [m] / treatment speed [m / sec]

[0105] The polar component value 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 goniometer (DMs - 401 manufactured by Kyowa Interface Science Co., Ltd.). The contact angle was measured with an appropriate amount of each liquid being 2.5 μl, and the liquid 1 second after droplet deposition. For the calculation of the surface free energy (= polar component value + dispersion component value) and its respective component values, the commonly used Owens - Wendt - Rabel - Kaelble (WORK, Kaelble - Uy) method was used. The polar component value of the surface free energy of the second surface after plasma treatment was 0.1 mJ / m 2

[0106] Subsequently, a coating agent obtained by mixing the following liquid A and liquid B in a mass ratio of 6:4 was applied by a gravure coating method onto the gas barrier layer 20 and dried to form a coating layer 30 with a thickness of 0.4 μm. Solution A: 89.6 g of hydrochloric acid (0.1 N) was added to 10.4 g of tetraethoxysilane and stirred for 30 minutes for hydrolysis to obtain a hydrolysis solution with a solid content of 3 wt% (in terms of SiO2). Solution B: A 3 wt% aqueous / isopropyl alcohol solution of polyvinyl alcohol (weight ratio of water:isopropyl alcohol 90:10) As described above, the gas barrier film according to Example 1 was produced.

[0107] (Example 2) The plasma treatment intensity was set to 100 W·sec / m 2 Except for this point, the gas barrier film according to Example 2 was produced in 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 It was.

[0108] (Example 3) The plasma treatment intensity was set to 300 W·sec / m 2 Except for this point, the gas barrier film according to Example 3 was produced in the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 0.4 mJ / m 2 It was.

[0109] (Example 4) The plasma treatment intensity was set to 500 W·sec / m 2 Except for this point, the gas barrier film according to Example 4 was produced in 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 It was.

[0110] (Example 5) The plasma treatment intensity was set to 100 W·sec / m 2 Except for the point of performing plasma treatment using O2 gas, the gas barrier film according to Example 5 was produced in 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 It was.

[0111] (Example 6) The plasma treatment intensity was set to 300 W·sec / m 2Except for the points specified, a gas barrier film according to Example 6 was produced in 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 It was.

[0112] (Example 7) As the base material layer 10, 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 homopolymer layer of polypropylene (thickness 19 μm) in the layer below the first surface including the second surface was used. Except for this point, a gas barrier film according to Example 7 was produced in the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 0.1 mJ / m 2 It was.

[0113] (Example 8) Except for the point where the plasma treatment intensity was set to 100 W·sec / m 2 a gas barrier film according to Example 8 was produced in the same procedure as in Example 7. The polar component value of the surface free energy of the second surface was 0.2 mJ / m 2 It was.

[0114] (Example 9) Except for the point where the plasma treatment intensity was set to 300 W·sec / m 2 a gas barrier film according to Example 9 was produced in the same procedure as in Example 7. The polar component value of the surface free energy of the second surface was 0.8 mJ / m 2 It was.

[0115] (Example 10) Except for the point where the plasma treatment intensity was set to 500 W·sec / m 2 a gas barrier film according to Example 10 was produced in the same procedure as in Example 7. The polar component value of the surface free energy of the second surface was 1.2 mJ / m 2 It was.

[0116] (Example 11) Except for the point where the plasma treatment intensity was set to 100 W·sec / m 2Except for performing plasma treatment using O2 gas, a gas barrier film according to Example 11 was produced in 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 It was.

[0117] (Example 12) Except for setting the plasma treatment intensity to 300 W·sec / m 2 A gas barrier film according to Example 12 was produced in the same procedure as in Example 11. The polar component value of the surface free energy of the second surface was 3.0 mJ / m 2 It was.

[0118] (Comparative Example 1) Except for not performing plasma treatment on the second surface, a gas barrier film according to Comparative Example 1 was produced in the same procedure as in Example 1. The polar component value of the surface free energy of the second surface was 0.0 mJ / m 2 It was.

[0119] (Comparative Example 2) Except for not performing plasma treatment on the second surface, a gas barrier film according to Comparative Example 2 was produced in the same procedure as in Example 7. The polar component value of the surface free energy of the second surface was 0.0 mJ / m 2 It was.

[0120] The following evaluations were performed on the gas barrier films according to the examples and comparative examples. (Adhesion evaluation of the second surface) On the second surface of the gas barrier film according to each example, an unstretched polypropylene film (ZK207 manufactured by Toray) with a thickness of 70 μm was laminated by dry lamination using a two-component curable polyurethane-based adhesive to provide a heat seal layer. Further, on the coating layer 30, a stretched polypropylene film (U1 manufactured by Mitsui Chemicals Toagosei) with a thickness of 20 μm was laminated by dry lamination using a two-component curable polyurethane-based adhesive to provide a surface layer, and a barrier laminate according to each example was produced. For 180° peel, test pieces were cut out from the barrier laminates of each example in accordance with JIS K 6854-2, and for T-shaped peel, in accordance with JIS K 6854-3. The peel strength between the base material layer and the heat seal layer was measured using an Orientech tensilon universal testing machine RTC-1250. Two types of measurements were performed: T-shaped peel and 180° peel. If the peel strength is 1 N / 15 mm or more in either T-shaped peel or 180° peel, it can be said that there is sufficient adhesion on the second side.

[0121] (Blocking Evaluation) Two 70 mm square samples were cut out from the gas barrier film of each example and stacked. Using a CO-201 permanent distortion tester blocking tester manufactured by Tester Sangyo Co., Ltd., a pressure of 200 kg was applied to the stacked samples and stored at 50 °C for 2 days. Thereafter, in accordance with JIS K 6854-2 and JIS K 6854-3, the peel strength between the upper sample and the lower sample was measured using an autograph manufactured by Shimadzu Corporation. That is, in the blocking evaluation, a peel test was performed between the second side of the base material layer of the upper sample and the coating layer of the lower sample. Two types of measurements were performed: T-shaped peel and 180° peel. When the peel strength showed 0.1 N / 15 mm or more in any of the measurements, it was defined that blocking had occurred. 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 side was 1 N / 15 mm or more in all cases of T-shaped peel, and it was confirmed that the heat seal layer provided on the second side was sufficiently adhered to the base material layer. In Examples 1 to 6 where the second side was a copolymer layer, the peel strength was also 1 N / 15 mm or more in 180° peel. In Examples 7 to 12 where the second side is a homopolymer layer, the average value of the minimum and maximum values of the 180° peel measurement was taken as the peel strength, and in all cases it was 1 N / 15 mm or more, confirming that the adhesion between the base material layer and the heat seal layer was sufficient. In Examples 7 to 12, dipping was observed in the 180° peel. Dipping is a phenomenon in which the peel strength changes intermittently by alternately repeating the progress and stop of peeling without the peel surface peeling smoothly. In Table 1, (*) is attached to the peel strength of the samples in which dipping was observed in the 180° peel. In Examples 1 to 6 that satisfy 2.0 N / 15 mm or more in the 180° peel in the adhesion evaluation of the second side, it can be seen that the adhesion of the second side 10b of the base material layer 10 is good and the occurrence of dipping in the peel test can be suppressed. Furthermore, in Examples 1 to 4 and Examples 7 to 10 where the polar component value of the surface free energy of the second side is less than 1.3 mJ / m 2 the peel strength in the blocking evaluation was less than 0.1 N / 15 mm in both the T-shaped and 180° cases, and blocking was sufficiently suppressed.

[0124] On the other hand, in Comparative Example 1 and Comparative Example 2, although blocking did not occur, the value of the peel strength in the adhesion evaluation of the second side was low, and the adhesion between the base material layer and the heat seal layer was insufficient.

[0125] Hereinafter, the present invention will be described in more detail using other examples. The technical scope of the present invention is not limited in any way based only on the specific contents of these examples.

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

[0127] In a vacuum apparatus, SiO was sublimated, and a gas barrier layer 20 (thickness: 30 nm) made of silicon oxide (SiOx) was formed on the EVOH layer by electron beam evaporation method. Furthermore, while maintaining the vacuum state, using a RIE (Reactive Ion Etching) processing apparatus, the second surface of the base material layer 10 was subjected to plasma treatment with Ar gas at a plasma treatment intensity of 83 W·sec / m 2 Note that the plasma treatment intensity was calculated by the following formula. · Plasma treatment intensity = power density [W / m 2 × treatment time [sec] · Power density [W / m 2 = input power [W] / cathode area [m 2 · Treatment time [sec] = electrode MD width [m] / treatment speed [m / sec]

[0128] Subsequently, a coating agent obtained by mixing the following liquid A and liquid B at a mass ratio of 6:4 was applied by a gravure coating method onto the gas barrier layer 20, and dried to form a coating layer 30 with a thickness of 0.4 μm. Liquid A: A hydrolysis solution with a solid content of 3 wt% (in terms of SiO2) obtained by adding 89.6 g of hydrochloric acid (0.1 N) to 10.4 g of tetraethoxysilane and stirring for 30 minutes for hydrolysis Liquid B: A 3 wt% aqueous / isopropyl alcohol solution of polyvinyl alcohol (weight ratio of water:isopropyl alcohol 90:10) Thus, a gas barrier film according to Example 2-1 was produced.

[0129] ​The polar component value of the surface free energy of the second side after the completion of the gas barrier film was calculated based on the contact angle values of water and diiodomethane measured using a goniometer (DMs-401 manufactured by Kyowa Interface Science Co., Ltd.). The contact angle was measured with an appropriate amount of each liquid being 2.5 μl, and the liquid 1 second after droplet deposition was measured. For the calculation of the surface free energy (= polar component value + dispersion component value) and each of its component values, the commonly used Owens-Wendt-Rabel-Kaelble (WORK, Kaelble-Uy) method was used. The polar component value of the surface free energy of the second side was 0.1 mJ / m 2 was obtained.

[0130] (Example 2-2) The copolymer layer on the second side was formed of a copolymer of propylene and ethylene, and a gas barrier film according to Example 2-2 was produced in the same procedure as in Example 2-1, except that plasma treatment using O2 gas was performed using a magnetron sputtering device (MF treatment device) with an MF power source at a treatment intensity of 331 W·sec / m 2 The polar component value of the surface free energy of the second side was 0.2 mJ / m 2 was obtained.

[0131] (Example 2-3) A gas barrier film according to Example 2-3 was produced in the same procedure as in Example 2-2, except that the plasma treatment intensity was set to 993 W·sec / m 2 The polar component value of the surface free energy of the second side was 0.3 mJ / m 2 was obtained.

[0132] (Example 2-4) The copolymer layer on the second side was formed of a copolymer of propylene and ethylene, and a gas barrier film according to Example 2-4 was produced in the same procedure as in Example 2-1, except that the plasma treatment intensity was set to 300 W·sec / m 2 The polar component value of the surface free energy of the second side was 0.4 mJ / m 2 was obtained.

[0133] (Example 2-5) The plasma treatment intensity was set to 500 W·sec / m 2 A gas barrier film according to Example 2-5 was produced in the same procedure as in Example 2-4, except that the point where the plasma treatment intensity was set to 500 W·sec / m 2 was excluded. The polar component value of the surface free energy of the second surface was 1.0 mJ / m

[0134] (Example 2-6) The copolymer layer on the second surface side was formed of a copolymer of propylene and ethylene, and a gas barrier film according to Example 2-6 was produced in the same procedure as in Example 2-1, except that plasma treatment with a treatment intensity of 100 W·sec / m 2 using O2 gas was performed. The polar component value of the surface free energy of the second surface was 1.3 mJ / m 2 was excluded. The polar component value of the surface free energy of the second surface was 1.3 mJ / m

[0135] (Example 2-7) A gas barrier film according to Example 2-7 was produced in the same procedure as in Example 2-1, except that the plasma treatment intensity was set to 500 W·sec / m 2 The polar component value of the surface free energy of the second surface was 1.5 mJ / m 2 was excluded. The polar component value of the surface free energy of the second surface was 1.5 mJ / m

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

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

[0138] (Comparative Example 2-3) The gas barrier film according to Comparative Example 2-3 was produced in the same procedure as 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 was obtained.

[0139] (Comparative Example 2-4) The gas barrier film according to Comparative Example 2-4 was produced in the same procedure as 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 was obtained.

[0140] (Comparative Example 2-5) The gas barrier film according to Comparative Example 2-5 was produced in the same procedure as Example 2-2, except that the thickness of the polypropylene homopolymer layer was 19 μm, no copolymer layer was provided on the second surface, and the plasma treatment intensity was 1325 W·sec / m 2 The polar component value of the surface free energy of the second surface was 0.4 mJ / m 2 was obtained.

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

[0142] (Comparative Example 2-7) The gas barrier film according to Comparative Example 2-7 was produced in the same procedure as Comparative Example 2-6, except that the plasma treatment intensity was 300 W·sec / m 2 The polar component value of the surface free energy of the second surface was 2.0 mJ / m 2 was obtained.

[0143] (Comparative Example 2-8) A gas barrier film according to Comparative Example 2-8 was produced in the same procedure as Comparative Example 2-7, except that the plasma treatment intensity was set to 500 W·sec / m 2 . The polar component value of the surface free energy of the second surface was 3.8 mJ / m 2 .

[0144] The following evaluations were performed on the gas barrier films according to the examples and comparative examples. (Adhesion Evaluation of the Second Surface) An unstretched polypropylene film (ZK207 manufactured by Toray Industries, Inc.) with a thickness of 70 μm was laminated on the second surface of the gas barrier film according to each example by dry lamination using a two-component curable polyurethane-based adhesive to provide a heat seal layer. Further, a stretched polypropylene film (U1 manufactured by Mitsui Chemicals Toatsu Chemicals, Inc.) with a thickness of 20 μm was laminated on the coating layer 30 by dry lamination using a two-component curable polyurethane-based adhesive to provide a surface layer, and a barrier laminate according to each example was produced. Test pieces were cut out from the barrier laminates of each example in accordance with JIS K 6854-2 for 180° peel and JIS K 6854-3 for T-peel, and the peel strength between the base material layer and the heat seal layer was measured using an Orientech tensilon universal testing machine RTC-1250. Two types of measurements were performed: T-peel and 180° peel. If the peel strength is 1 N / 15 mm or more in either T-peel or 180° peel, it can be said that there is sufficient adhesion on the second surface.

[0145] (Blocking Evaluation) Two square samples with a side length of 70 mm were cut out from the gas barrier film of each example and stacked. Using a CO-201 permanent distortion tester blocking tester manufactured by Tester Sangyo Co., Ltd., a pressure of 200 kg was applied to the stacked samples and stored at 50°C for 2 days. Subsequently, the peel strength between the upper sample and the lower sample was measured using a Shimadzu autograph in accordance with JIS K 6854-2 and JIS K 6854-3. That is, in the blocking evaluation, a peel test was performed between the second surface of the base material of the upper sample and the coating layer of the lower sample. Two types of measurements, T-peel and 180° peel, were carried out. When the peel strength was 0.1 N / 15 mm or more in any of the measurements, it was defined that blocking occurred. 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 more in both T-peel and 180°, and it was confirmed that the heat seal layer provided on the second surface side was sufficiently adhered to the base material layer. Furthermore, in Examples 2-1 to 2-5 where the polar component value of the surface free energy of the second surface was less than 1.3 mJ / m 2 the peel strength in the blocking evaluation was less than 0.1 N / 15 mm in both T-peel and 180°, and blocking was sufficiently suppressed.

[0148] On the other hand, in Comparative Examples 2-1 to 2-3, the value of the peel strength in the adhesion evaluation of the second surface was low, and the adhesion between the base material layer and the heat seal layer was insufficient. In Comparative Examples 2-4 to 2-8 where the second surface was a homopolymer layer, a dipping phenomenon in which low and high values of the peel strength were repeated in 180° peel in the adhesion evaluation of the second surface was observed. As an example, the graph of the measurement chart of 180° peel in Comparative Example 2-5 where the dipping phenomenon occurred is shown in FIG. 4.

[0149] Here, the dipping phenomenon is a phenomenon in which the peeling strength changes intermittently by alternately repeating the progress and stop of peeling without the peeling surface peeling smoothly. Further, the dipping phenomenon is likely to occur when the adhesion strength in the direction in which peeling progresses is not constant within the adhesion surface of the two layers and there is variation in the adhesion strength depending on the location. In a barrier laminate having variation in the adhesion strength between the base material layer and the heat seal layer, there is a possibility of bag breakage starting from a portion where the adhesion strength is weak. Therefore, by checking the presence or absence of the dipping phenomenon, it is possible to check the uniformity of the adhesion of the second surface and the uniformity of the bag breakage strength of the barrier laminate.

[0150] In Comparative Examples 2-4 to 2-8 in Table 2, since the dipping phenomenon was observed, the minimum value and the maximum value of the peeling strength are shown in the column of the measurement results of 180° peeling for the adhesion evaluation of the second surface. From the results of Comparative Examples 2-4 to 2-8, it can be judged that the dipping phenomenon has occurred when the difference between the maximum value and the minimum value of the peeling strength 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 value and the minimum value of the peeling strength was minute and the dipping phenomenon was not observed during the test, so the average value of the measured values is shown in Table 2 as the peeling strength. Based on the evaluation results shown in Table 2, the dipping phenomenon is considered to be unlikely to occur when the difference between the maximum value and the minimum value of the peeling strength 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 or more, and blocking also occurred.

[0152] As described above, one embodiment and examples of the present invention have been described, but the specific configuration is not limited to this embodiment, and configurations such as changes and combinations within the scope not departing from the gist of the present invention are also included.

Explanation of Signs

[0153] 1 Gas barrier film 10 Substrate layer 10a First side 10b Second side 20 Gas barrier layer 30 Coating layer 40 Heat seal layer 60 Surface layer 61 Printing layer 101, 102 Barrier laminate

Claims

1. A base material layer having a layer mainly composed of polypropylene or polyethylene and a copolymer layer composed of a copolymer of polypropylene and polyethylene or a terpolymer of propylene, ethylene and 1-butene, A gas barrier layer formed on a first surface opposite to a second surface on which the copolymer layer of the base material layer is provided, A heat seal layer which is an unstretched film mainly composed of polypropylene or polyethylene and is bonded to the second surface by dry lamination using a two-component curable polyurethane-based adhesive, Comprising, The peel strength between the second surface of the base material layer and the heat seal layer is, In 180° peel conforming to JIS K 6854-2, it is 1.0 N / 15 mm or more and 7.0 N / 15 mm or less, In T-peel conforming to JIS K 6854-3, it is 1.0 N / 15 mm or more and 4.0 mm / 15 mm or less, Plasma intensity: 67 W·sec / m ２ 500 W·sec / m or more ２ 4 or less, and after vacuum plasma treatment using Ar gas or O ２ gas, the polar component value of the surface free energy of the second surface is 0.1 mJ / m ２ 1.6 mJ / m or more ２ 4 or less A gas barrier film.

2. The polar component value of the surface free energy of the second surface is 0.1 mJ / m ２ or more and less than 1.3 mJ / m ２ is as follows The gas barrier film according to Claim 1.

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

4. On the surface that becomes the first surface of the base material layer, a layer made of any one of polypropylene, polyethylene, a composite of polypropylene and polyethylene, a composite of polypropylene, polyethylene and α-olefin, polyvinyl alcohol, and ethylene-vinyl alcohol copolymer is further provided, The gas barrier film according to Claim 1 or 2.

5. Further comprising a coating layer formed on the gas barrier layer, The coating layer contains any one of metal alkoxide, hydrolyzate of metal alkoxide, water-soluble polymer, polycarboxylic acid-based polymer, polyvalent metal compound, and polyvalent metal salt of carboxylic acid which is a reaction product of polycarboxylic acid-based polymer and polyvalent metal compound, The gas barrier film according to Claim 1 or 2.

6. Further comprising an undercoat layer provided between the first surface and the gas barrier layer, The undercoat layer contains at least one of thermosetting resin, thermoplastic resin, ultraviolet curable resin, and electron beam curable resin, The gas barrier film according to Claim 1 or 2.

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

8. In the 180° peel, the difference between the maximum value and the minimum value of the peel strength is less than 0.3 N / 15 mm. The gas barrier film according to claim 1 or 2.

9. The gas barrier film according to claim 1 or 2, and a surface layer joined to the gas barrier film, wherein the main component is the same as that of the layer containing polypropylene or polyethylene as the main component of the base material layer. A barrier laminate.

10. The surface layer is joined to the gas barrier film by an adhesive. The barrier laminate according to claim 9.

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

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