Method for manufacturing a gas barrier film, gas barrier film, packaging film, and packaging material

Abstract

To provide a method for manufacturing a gas barrier film that can exhibit excellent gas barrier properties regardless of the heat resistance of the base film. [Solution] A method for producing a gas barrier film, comprising the steps of: forming an inorganic oxide layer on a substrate layer; applying an active energy ray-curable resin composition to the inorganic oxide layer to form a coating film; and curing the coating film by irradiating it with active energy rays to form an overcoat layer, wherein the active energy ray-curable resin composition contains an acrylic compound with a molecular weight of 300 or more.

Description

[Technical Field]

[0001] This disclosure relates to a method for manufacturing a gas barrier film, a gas barrier film manufactured by said manufacturing method, a packaging film comprising said gas barrier film, and a packaging material made from said packaging film. [Background technology]

[0002] Packaging materials used for food, pharmaceuticals, electronic components, machine parts, etc., require gas barrier properties to prevent the intrusion of gases (water vapor, oxygen, etc.) that alter the contents, in order to suppress deterioration and spoilage of the contents and maintain their function and quality. For this reason, film materials with gas barrier properties (gas barrier films) are used for these packaging materials.

[0003] As a packaging film equipped with a gas barrier film, for example, Patent Document 1 proposes a laminated material manufactured by preparing a polyurethane resin composition by mixing a polyurethane resin, nitrocellulose, a silane coupling agent, and a filler with a solvent and diluent, on the other hand, providing a thin film of inorganic oxide mainly consisting of a silicon oxide vapor deposition film by plasma chemical vapor deposition on one side of a flexible plastic substrate, then using the above polyurethane resin composition and coating it onto the surface of the thin film of inorganic oxide provided on one side of the flexible plastic substrate to form a coating thin film of the polyurethane resin composition, and then coating the surface of the coating thin film of the polyurethane resin composition with an adhesive made of a two-component curable polyurethane resin that is formed by a curing reaction between a polyester polyol or polyether polyol and an isocyanate, and then laminating at least a heat-sealable resin layer via the adhesive layer. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2000-167973 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] Generally, gas barrier films are manufactured by providing a gas barrier layer made of a material having gas barrier properties on the surface of a resin substrate. For example, in the above-mentioned Patent Document 1, the coating thin film made of a polyurethane resin composition corresponds to the gas barrier layer. The coating thin film is formed by applying the polyurethane resin composition to the target by a wet coating method such as the roll coating method, and then drying it with hot air to remove the solvent.

[0006] However, the heat generated during hot air drying can deform the base film, potentially causing cracks in the gas barrier layer and degrading its gas barrier properties (especially oxygen barrier properties). In recent years, from the perspective of improving recyclability, there has been a trend to design packaging materials using a single polyolefin material, and polyolefin resin films such as OPP (oriented polypropylene) and PE (polyethylene) are being adopted as base films. However, such films are more susceptible to the effects of the heat mentioned above, and the degradation of their gas barrier properties is a greater concern.

[0007] This disclosure is made in view of the above circumstances and aims to provide a method for manufacturing a gas barrier film that can exhibit excellent gas barrier properties regardless of the heat resistance of the base film. This disclosure also aims to provide a gas barrier film manufactured by the said manufacturing method, a packaging film comprising the gas barrier film, and a packaging material made from the said packaging film. [Means for solving the problem]

[0008] To solve the above problems, the inventors found that it is important to form a gas barrier layer by curing a resin composition containing a specific acrylic compound with active energy rays, and have completed the manufacturing method of this disclosure. In other words, one aspect of this disclosure provides the following invention.

[0009] [1] A step of forming an inorganic oxide layer on a substrate layer, The process involves applying an active energy ray-curable resin composition onto the inorganic oxide layer to form a coating film, The process includes a step of curing the aforementioned coating film by irradiating it with active energy rays to form an overcoat layer, A method for producing a gas barrier film, wherein the active energy ray curable resin composition contains an acrylic compound having a molecular weight of 300 or more. [2] The material comprises a base layer, an inorganic oxide layer, and an overcoat layer in this order. The overcoat layer is a cured product of an active energy ray curable resin composition having a crosslinked structure. The aforementioned active energy ray-curable resin composition comprises an acrylic compound with a molecular weight of 300 or more, and is a gas barrier film. [3] The gas barrier film according to [2], wherein the active energy ray curable resin composition comprises the acrylic compound having an isocyanurate skeleton. [4] The gas barrier film according to [3], wherein the active energy ray curable resin composition comprises two or more types of acrylic compounds having an isocyanurate skeleton. [5] The gas barrier film according to [3] or [4], wherein the content of the hydroxyl group-containing acrylic compound having an isocyanurate skeleton is 30% by mass or more, based on the total amount of the acrylic compound having an isocyanurate skeleton. [6] The gas barrier film according to any one of [2] to [5], wherein the active energy ray curable resin composition further comprises an acrylic compound with a molecular weight of less than 300. [7] The gas barrier film according to any one of [2] to [6], wherein the active energy ray curable resin composition further comprises a carboxyl group-containing acrylic compound having a molecular weight of less than 300. [8] The gas barrier film according to [6], wherein the content of the acrylic compound having a molecular weight of less than 300 is 10 to 2000 parts by mass per 100 parts by mass of the acrylic compound having a molecular weight of 300 or more. [9] The gas barrier film according to [7], wherein the molecular weight of the carboxyl group-containing acrylic compound is 100 or more and less than 300.

[10] The gas barrier film according to [7] or [9], wherein the content of the carboxyl group-containing acrylic compound is 10 to 600 parts by mass per 100 parts by mass of the acrylic compound having a molecular weight of 300 or more.

[11] The gas barrier film according to any one of [2] to

[10] , wherein the base layer comprises a polyolefin resin.

[12] The gas barrier film according to any one of [2] to

[11] , wherein the thickness of the overcoat layer is 0.15 to 2 μm. A packaging film comprising a gas barrier film according to any one of

[13] [2] to

[12] , and a heat-sealable layer provided on the overcoat layer of the gas barrier film.

[14] Packaging material made from the packaging film described in

[13] . [Effects of the Invention]

[0010] This disclosure provides a method for manufacturing a gas barrier film that can exhibit excellent gas barrier properties regardless of the heat resistance of the base film. Furthermore, this disclosure provides a gas barrier film manufactured by the manufacturing method, a packaging film equipped with the gas barrier film, and a packaging material made from the packaging film. [Brief explanation of the drawing]

[0011] [Figure 1]FIG. 1 is a schematic cross-sectional view of a gas barrier film according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic cross-sectional view of a gas barrier film according to a second embodiment of the present disclosure. MODE FOR CARRYING OUT THE INVENTION

[0012] Embodiments of the present disclosure will be described below with reference to the drawings. The embodiments described below are more specific examples of any of the above aspects. The matters described below can be incorporated into each of the above aspects alone or in combination.

[0013] In addition, the embodiments shown below are examples of configurations for embodying the technical idea of the present disclosure, and the technical idea of the present disclosure is not limited by the materials, shapes, structures, etc. of the following constituent members. Various changes can be made to the technical idea of the present disclosure within the technical scope defined by the claims described in the claims.

[0014] In the drawings referred to below, the same parts are denoted by the same reference numerals. The drawings are schematic, and the relationship between dimensions in one direction and dimensions in another direction, and the relationship between the dimensions of one member and the dimensions of another member, etc. may be different from the actual ones.

[0015] In the present disclosure, the oxygen barrier property, which is one aspect of the gas barrier property, is evaluated by the oxygen transmission rate (OTR), and the smaller the value, the better the oxygen barrier property.

[0016] <Gas barrier film> The gas barrier film includes a base material layer, an inorganic oxide layer, and an overcoat layer in this order. <00:00109> The overcoat layer is a cured product of an active energy ray-curable resin composition having a crosslinked structure. The active energy ray-curable resin composition contains an acrylic compound having a molecular weight of 300 or more.

[0017] First, the first embodiment will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view of a gas barrier film according to the first embodiment of the present disclosure. The gas barrier film 100 comprises a base layer 10, a sub-layer 30, an inorganic oxide layer 40, and an overcoat layer 20 in this order.

[0018] A base layer 30 is formed on the base layer 10. An inorganic oxide layer 40 is formed on the base layer 30. An overcoat layer 20 is formed on the inorganic oxide layer 40.

[0019] In the gas barrier film, as described in the second embodiment, the underlayer 30 may not be provided.

[0020] Next, a second embodiment will be described with reference to Figure 2. Figure 2 is a schematic cross-sectional view of a gas barrier film according to a second embodiment of the present disclosure. The gas barrier film 200 is the same as the gas barrier film 100 but without the underlayer 30, and comprises a base layer 10, an inorganic oxide layer 40, and an overcoat layer 20 in that order.

[0021] The gas barrier films according to the first and second embodiments will be described below.

[0022] [Base material layer] Examples of resins constituting the base layer 10 include olefin resins such as polyethylene, polypropylene, polymers of olefins having 2 to 10 carbon atoms, and propylene-ethylene copolymers; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polyamide resins such as aliphatic polyamides such as nylon 6 and nylon 66, and aromatic polyamides such as polymetaxylylene adipamide; vinyl resins such as polystyrene, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; acrylic resins such as polymethyl methacrylate and acrylic monomers such as polyacrylonitrile, either alone or as copolymers; cellophane; and engineering plastics such as polycarbonate and polyimide. These resins may be used individually or in combination of two or more.

[0023] By using polyolefin resin films (especially polypropylene films) among these resins, it is possible to obtain monomaterial packaging materials with excellent recyclability.

[0024] The base layer 10 may be a single-layer film made of a single resin, or a single-layer or laminated film using multiple resins. The base layer 10 may also be a laminate of the above-mentioned resins on another base material (metal, wood, paper, ceramics, etc.).

[0025] The film constituting the base layer 10 may be an unstretched film, or a stretched film such as uniaxially stretched or biaxially stretched. From the viewpoint of excellent water vapor barrier properties, stretched polypropylene (OPP) film is particularly preferred as the base layer 10. When the base layer 10 includes an OPP film, there may be one or two or more layers of OPP film.

[0026] OPP film may be made by processing at least one polymer selected from homopolymers, random copolymers, and block copolymers into a film. Homopolymer is polypropylene consisting only of propylene monomers. Random copolymer is polypropylene in which propylene, the main monomer, and a small amount of comonomers different from propylene are randomly copolymerized to form a homogeneous phase. Block copolymer is polypropylene in which propylene, the main monomer, and the above comonomers copolymerize in a block-like manner or polymerize in a rubber-like manner to form a heterogeneous phase.

[0027] The surface of the base layer 10 on which the underlayer 30 or inorganic oxide layer 40 is formed may be subjected to surface treatments such as chemical treatment, solvent treatment, corona treatment, low-temperature plasma treatment, or ozone treatment. This can improve the adhesion between the base layer and the underlayer or inorganic oxide layer.

[0028] The film constituting the base layer 10 may contain additives such as fillers, antiblocking agents, antistatic agents, plasticizers, lubricants, and antioxidants. These additives may be used individually or in combination of two or more.

[0029] There are no particular restrictions on the thickness of the base layer 10, and it can be appropriately determined depending on the price and application, while considering its suitability as a packaging material and its suitability for lamination of other coatings. In practical terms, the thickness of the base layer 10 is preferably 3 to 200 μm, more preferably 5 to 120 μm, even more preferably 6 to 100 μm, and particularly preferably 10 to 30 μm.

[0030] [Base layer] The base layer 30 contains an organic polymer. The content of the organic polymer in the base layer 30 may be, for example, 70% by mass or more, or 80% by mass or more. Examples of organic polymers include polyacrylic resin, polyester resin, polycarbonate resin, polyol resin, polyurethane resin, polyamide resin, polyolefin resin, polyimide resin, melamine resin, phenolic resin, etc. Considering the hot water resistance of the adhesion strength between the base layer 10 and the inorganic oxide layer 40 or the overcoat layer 20, it is preferable that the base layer 30 contains at least one of a polyacrylic resin, a polyol resin, a polyurethane resin, a polyamide resin, or a reaction product of these organic polymers.

[0031] The base layer 30 may contain a silane coupling agent, organic titanate, modified silicone oil, etc.

[0032] More preferably, the organic polymer used in the base layer 30 is an organic polymer having a urethane bond, which is produced by the reaction of polyols having two or more hydroxyl groups at the molecular ends or in the molecular chain with an isocyanate compound, or an organic polymer containing a reaction product of polyols having two or more hydroxyl groups at the molecular ends or in the molecular chain with an organic silane compound such as a silane coupling agent or its hydrolysate. Either one or both of these may be used.

[0033] Examples of the polyols mentioned above include at least one selected from acrylic polyols, polyvinyl acetals, polystyrene polyols, and polyurethane polyols. Acrylic polyols may be obtained by polymerizing acrylic acid derivative monomers, or by copolymerizing acrylic acid derivative monomers with other monomers. Examples of acrylic acid derivative monomers include ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Examples of monomers copolymerized with acrylic acid derivative monomers include styrene.

[0034] The isocyanate compound enhances the adhesion between the substrate layer 10 and the inorganic oxide layer 40 or the overcoat layer 20 through the urethane bond formed by its reaction with the polyol. In other words, the isocyanate compound functions as a crosslinking agent or curing agent. Examples of isocyanate compounds include monomers such as aromatic tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aromatic aliphatic xylene diisocyanate (XDI), aliphatic hexamethylene diisocyanate (HMDI), isophorone diisocyanate (IPDI), a mixture of 1-methylcyclohexane-2,4-diisocyanate and 1-methylcyclohexane-2,6-diisocyanate (HTDI, hydrogenated TDI), and cyclohexylmethane diisocyanate (HMDI, hydrogenated MDI), polymers thereof, and derivatives thereof. The above-mentioned isocyanate compounds may be used individually or in combination of two or more.

[0035] Examples of silane coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, and 3-methacryloyloxypropylmethyldimethoxysilane. The organosilane compound may be a hydrolysate of these silane coupling agents. The organosilane compound may contain one of the above-mentioned silane coupling agents and their hydrolysates alone, or in combination of two or more.

[0036] The base layer 30 can be formed using a mixture obtained by blending the above-mentioned components in an organic solvent in any proportion. The mixture may contain, for example, curing accelerators such as tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts; antioxidants such as phenolic, sulfuric, and phosphite-based agents; leveling agents; flow regulators; catalysts; crosslinking reaction accelerators; fillers, etc.

[0037] There are no particular restrictions on the thickness of the underlayer 30; for example, it can be 0.005 to 5 μm. The thickness can be appropriately determined depending on the application or required properties. The thickness of the underlayer 30 is preferably 0.01 to 1 μm, and more preferably 0.01 to 0.5 μm. If the thickness of the underlayer 30 is 0.01 μm or more, sufficient adhesion strength between the base material layer 10 and the inorganic oxide layer 40 or overcoat layer 20 can be obtained, and gas barrier properties will also be good. If the thickness of the underlayer 30 is 1 μm or less, it becomes easier to form a uniform coated surface, and drying load and manufacturing costs can be suppressed.

[0038] As shown in Figure 2, if no underlayer is provided, the heating process applied to the base layer can be reduced. However, providing an underlayer makes it easier to improve the smoothness of the base layer surface, thus suppressing the decrease in gas barrier properties due to the deterioration of the film quality of the formed inorganic oxide layer.

[0039] [Inorganic oxide layer] Examples of inorganic oxides constituting the inorganic oxide layer 40 include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, tin oxide, zinc oxide, and indium oxide. In particular, aluminum oxide or silicon oxide are preferred because they offer excellent productivity and superior oxygen barrier and water vapor barrier properties under high temperature and high humidity conditions. The inorganic oxide layer 40 may be formed from one type of inorganic oxide, or from two or more inorganic oxides selected as appropriate.

[0040] The thickness of the inorganic oxide layer 40 can be 1 to 200 nm. If the thickness is 1 nm or more, excellent oxygen barrier and water vapor barrier properties are easily obtained. If the thickness is 200 nm or less, manufacturing costs can be kept low, and cracks caused by external forces such as bending and pulling are less likely to occur, making it easier to suppress deterioration of gas barrier properties.

[0041] The inorganic oxide layer 40 can be formed by known film deposition methods such as vacuum deposition, sputtering, ion plating, or plasma vapor deposition (CVD).

[0042] [Overcoat layer (gas barrier coating / oxygen barrier coating)] The overcoat layer 20 is a cured coating film containing an acrylic compound (a compound having an acryloyl group). For example, it is an organic polymer film obtained by curing a coating film, which is made by applying a solvent-free coating solution containing monomers and oligomers of an acrylic compound, i.e., an active energy ray curable resin composition, by irradiation with active energy rays such as EB (electron beam) or UV (ultraviolet). As can be understood from its manufacturing method, the overcoat layer is a cured product of an active energy ray curable resin composition having a crosslinked structure.

[0043] The active energy ray-curable resin composition contains at least an acrylic compound monomer (or oligomer), and may further contain additives such as a methacrylic compound (a compound having a methacryloyl group), a photoradical generator, or a silane coupling agent. Note that curing can be achieved using EB even if the composition does not contain a photoradical generator. From a hygienic standpoint, the composition does not need to contain a photoradical generator.

[0044] Acrylic compounds are generally low-cost and exhibit superior EB and UV curing rates compared to methacrylic compounds, making them highly reactive energy ray curable compounds. Reactive energy ray curable resin compositions may contain one or more acrylic compounds.

[0045] The active energy ray curable resin composition contains an acrylic compound with a molecular weight of 300 or more. Generally, coatings formed from acrylic compounds tend to have poor gas barrier properties, particularly oxygen barrier properties. However, by using an acrylic compound with a molecular weight of 300 or more, superior gas barrier properties can be achieved compared to using an acrylic compound with a molecular weight of less than 300. From this viewpoint, a molecular weight of 350 or more is preferable. On the other hand, from the viewpoint of the coating properties of the resin composition, the upper limit of the molecular weight can be 1900 or less, and further from the viewpoint of coating properties, the molecular weight may be 1000 or less, 700 or less, or 500 or less. From the viewpoint of achieving both gas barrier properties and coating properties, the molecular weight is preferably 300 to 1900, 300 to 1000, 350 to 1000, 350 to 700, or 350 to 500.

[0046] Examples of acrylic compounds with a molecular weight of 300 or more include stearyl acrylate, methoxy PEG#400 acrylate, methoxy PEG#600 acrylate, methoxy PEG#1000 acrylate, methoxy-polyethylene glycol acrylate, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, PEG#200 diacrylate, PEG#400 diacrylate, PEG#600 diacrylate, PEG#1000 diacrylate, tripropylene glycol diacrylate, polypropylene glycol diacrylate, polytetramethylene glycol diacrylate, tricyclodecanedimethanol diacrylate, neopentyl glycol hydroxypivalate diacrylate, and bisphenol A ethylene glycol diether diacrylate. You can use acrylate, bisphenol A polyethylene glycol diether diacrylate, 1,6-hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bisacrylate, bisphenol A diglycidyl ether acrylic acid adduct, glycerin 1,3-diglycerolate diacrylate, tris(2-hydroxyethyl)isocyanurate diacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, EO-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, EO-modified pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, EO-modified dipentaerythritol hexaacrylate, etc.

[0047] In addition, epoxy acrylates, urethane acrylates, polyester acrylates, and other materials with a molecular weight of 300 or more can be used.

[0048] From the viewpoint of gas barrier properties, acrylic compounds having an isocyanurate skeleton can be used. For example, acrylic compounds having an isocyanurate skeleton such as tris(2-hydroxyethyl)isocyanurate diacrylate and tris(2-hydroxyethyl)isocyanurate triacrylate are preferably used.

[0049] The active energy ray curable resin composition may contain two or more acrylic compounds having an isocyanurate skeleton, from the viewpoint of adjusting the coating properties of the composition.

[0050] The gas barrier properties of organic polymers depend on their free volume and cohesive energy. Free volume refers to the gaps between polymer molecules; a smaller free volume results in higher gas barrier properties. To suppress the thermal motion of molecules, it is preferable to use resins with high glass transition temperatures and to increase their crosslinking density. Many acrylic resins have relatively low glass transition temperatures.

[0051] Cohesive energy is the energy related to the magnitude of interaction between functional groups and polar groups with permeate gases. Chlorine groups, fluoro groups, and hydroxyl groups are known to be excellent for oxygen gas, with hydroxyl groups being particularly effective. Therefore, acrylic compounds containing hydroxyl groups (hydroxyl group-containing acrylic compounds) can be used to form organic polymer films with excellent gas barrier properties.

[0052] Examples of hydroxyl group-containing acrylic compounds that can be used include 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, 1,6-hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bisacrylic acid, bisphenol A diglycidyl ether acrylic acid adduct, glycerin 1,3-diglycerolate diacrylate, tris(2-hydroxyethyl)isocyanurate diacrylate, and dipentaerythritol pentaacrylate.

[0053] The number of acryloyl groups contained in one molecule of acrylic compound is N. A The number of hydroxyl groups is N B Let these N A , N B When the value of equation (1) below is calculated using the following method, it is preferable that the value of equation (1) is 4 or greater. N A ×2+N B ×3≧4 ···(1)

[0054] When the value of formula (1) is 4 or more, compared with the case where it is less than 4, the crosslinking density by the acryloyl group can be improved, so it becomes easier to form a film with a dense structure. As a result, it becomes more difficult for the film to permeate oxygen molecules, and it is easier to exhibit more excellent gas barrier properties. From this viewpoint, the value of formula (1) is preferably 5 or more, 6 or more, or 7 or more. On the other hand, the upper limit of the value of formula (1) can be, for example, 65, but from the viewpoint of suppressing embrittlement of the film due to the internal structure becoming too dense and maintaining ease of handling (flexibility) as a film, the upper limit of the value of formula (1) may be 30 or less, and may be 15 or less.

[0055] The number N of acryloyl groups contained in one molecule of the acrylic compound A can take values from 1 to 15. N A being 1 or more enables a curing reaction to occur, and N A being 15 or less makes it easy to maintain the flexibility of the film. As a result, cracking of the film and peeling from the base material layer are less likely to occur, and it is easy to ensure gas barrier properties. From this viewpoint, N A may be 2 to 10, may be 2 to 6, or may be 3 to 6.

[0056] The number N of hydroxyl groups contained in one molecule of the acrylic compound B can take values from 0 to 20. The acrylic compound may not contain a hydroxyl group, but as described above, when it contains a hydroxyl group, the gas barrier properties are likely to be improved. N B being 20 or less makes it easy to maintain an appropriate viscosity of the acrylic compound. As a result, the coating property becomes good, and it becomes easy to form a homogeneous film. From this viewpoint, N B may be 0 to 15, or may be 1 to 8.

[0057] Examples of acrylic compounds with a value of 4 or more in formula (1) include tricyclodecanedimethanol diacrylate, 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid, 1,6-hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bisacrylic acid, bisphenol A diglycidyl ether acrylic acid adduct, glycerin 1,3-diglycerolate diacrylate, tris(2-hydroxyethyl)isocyanurate diacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, EO-modified trimethylolpropane triacrylate, pentaerythritol tetraacrylate, EO-modified pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, and EO-modified dipentaerythritol hexaacrylate.

[0058] The active energy ray curable resin composition may further contain an acrylic compound with a molecular weight of less than 300, from the viewpoint of the coating properties of the composition. In other words, the active energy ray curable resin composition may contain acrylic compounds with a molecular weight of 300 or more and acrylic compounds with a molecular weight of less than 300.

[0059] Examples of acrylic compounds with a molecular weight of less than 300 include phenoxyethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, ethoxy-diethylene glycol acrylate, methoxy-triethylene glycol acrylate, methoxydipropylene glycol acrylate, butoxyethyl acrylate, butoxydiethylene glycol acrylate, butyl acrylate, isoamyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, methoxyethylene glycol acrylate, methoxydiethylene glycol acrylate, methoxyPEG#200 acrylate, 2-hydroxy-3 phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2 Acryloyloxyethyl phthalic acid, acrylic acid, 2-acryloyloxyethyl acid phosphate, dimethylaminoacrylate, diethylaminoacrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, cyclohexyl acrylate, phenooxyethyl acrylate, isobornyl acrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, neopentyl glycol diacrylate, glycerin diacrylate, glycerin triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, etc. can be used.

[0060] In addition to the coatability of the active energy ray-curable resin composition, the active energy ray-curable resin composition may further contain a carboxyl group-containing acrylic compound as an acrylic compound with a molecular weight of less than 300, from the viewpoint of improving the adhesion between the cured overcoat layer and the inorganic oxide layer. Since polar carboxyl groups readily interact strongly with the inorganic oxide layer, the adhesion between the overcoat layer and the inorganic oxide layer tends to be further improved. In other words, the active energy ray curable resin composition may contain acrylic compounds with a molecular weight of 300 or more, and carboxyl group-containing acrylic compounds with a molecular weight of less than 300, but the composition may also contain acrylic compounds with a molecular weight of 300 or more, as well as carboxyl group-free acrylic compounds with a molecular weight of less than 300 and carboxyl group-containing acrylic compounds with a molecular weight of less than 300.

[0061] As carboxyl group-containing acrylic compounds, for example, in addition to the above-mentioned 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid, and 2-acryloyloxyethyl hexahydrophthalic acid, 2-carboxyethyl acrylate and ω-carboxycaprolactone monoacrylate can be used. Of these, 2-acryloyloxyethyl succinic acid or 2-acryloyloxyethyl hexahydrophthalic acid are preferred from the viewpoint of compatibility with acrylic compounds with a molecular weight of 300 or more and gas barrier properties, and 2-acryloyloxyethyl succinic acid is more preferred.

[0062] Carboxylate-containing acrylic compounds with a molecular weight of less than 300 may be sized to fill the gaps between the crosslinked structures of acrylic compounds with a molecular weight of 300 or more. This facilitates a synergistic effect of improving adhesion between the overcoat layer and the inorganic oxide layer, as well as gas barrier properties. From this viewpoint, the molecular weight of the carboxylate-containing acrylic compound may be 250 or less, or 200 or less. On the other hand, from the viewpoint of the curability of the composition, the molecular weight may be 100 or more. Preferably, the molecular weight of the carboxylate-containing acrylic compound is 100 or more but less than 300, 100 or more but 250 or less, or 100 or more but 200 or less.

[0063] From the viewpoint of forming a cross-linked structure inside the coating by EB curing and UV curing, it is preferable that at least one of the acrylic compounds used has two or more acryloyl groups.

[0064] The active energy ray-curable resin composition may further contain a methacrylic compound (a compound having a methacryloyl group) from the viewpoint of controlling reactivity and heat resistance. The methacrylic compound is also an excellent active energy ray-curable resin that can form organic polymer films at low cost.

[0065] Any methacrylic compound exhibiting excellent EB curability and UV curability can be used as the methacrylic compound.

[0066] For example, as methacrylic compounds, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, ethoxydiethylene glycol methacrylate, methoxyethylene glycol methacrylate, methoxydiethylene glycol methacrylate, methoxytriethylene glycol methacrylate, methoxydipropylene glycol methacrylate, butoxyethyl methacrylate, butoxydiethylene glycol methacrylate, butyl methacrylate, isoamyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, stearyl methacrylate, methoxy PEG #200 methacrylate, methoxy PEG #400 methacrylate, methoxy PEG #600 methacrylate, methoxy PEG #1000 methacrylate, methoxy-polyethylene glycol methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-methacryloyloxyethyl succinic acid, 2-methacryloyloxyethyl hexahydrate Lophthalic acid, 2-methacryloyloxyethyl phthalate, 2-methacryloyloxyethyl-2-hydroxyethyl phthalate, 2-methacryloyloxyethyl-2-hydroxyepropyl phthalate, methacrylic acid, 2-methacryloyloxyethyl acid phosphate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, cyclohexyl methacrylate, phenoxyethyl methacrylate, isovonyl methacrylate Diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, PEG#200 dimethacrylate, PEG#400 dimethacrylate, PEG#600 dimethacrylate, PEG#1000 dimethacrylate, polyethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, 1,9-Nonanediol dimethacrylate, ditetramethylene glycol dimethacrylate, tritetramethylene glycol dimethacrylate, neopentyl glycol dimethacrylate, tricyclodecane dimethanol dimethacrylate, neopentyl glycol hydroxypivalate dimethacrylate, bisphenol A ethylene glycol diether dimethacrylate, bisphenol A polyethylene glycol diether dimethacrylate, glycerin dimethacrylate, 1,6-hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bismethacrylate, bisphenol A diglycidyl ether methacrylate adduct, glycerin 1 ,3-Diglycerolate dimethacrylate, tris(2-hydroxyethyl)isocyanurate dimethacrylate, tris(2-hydroxyethyl)isocyanurate trimethacrylate, trimethylolpropane trimethacrylate, EO-modified trimethylolpropane trimethacrylate, glycerin trimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, EO-modified pentaerythritol tetramethacrylate, dipentaerythritol pentamethacrylate, dipentaerythritol hexamethacrylate, 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol, etc. can be used.

[0067] In addition to the above, epoxy methacrylate, urethane methacrylate, polyester methacrylate, and the like can also be used.

[0068] Similar to acrylic compounds, compounds having methacryloyl groups with hydroxyl groups (hydroxyl group-containing methacrylic compounds) can be used from the viewpoint of forming organic polymer films with excellent gas barrier properties.

[0069] Examples of hydroxyl group-containing methacrylate compounds that can be used include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, 2-hydroxy-3-phenoxypropyl methacrylate, 2-methacryloyloxyethyl-2-hydroxyethyl phthalic acid, 2-methacryloyloxyethyl-2-hydroxypropyl phthalic acid, glycerin dimethacrylate, 1,6-hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bismethacrylate, bisphenol A diglycidyl ether methacrylate adduct, glycerin 1,3-diglycerolate dimethacrylate, tris(2-hydroxyethyl)isocyanurate dimethacrylate, pentaerythritol trimethacrylate, and dipentaerythritol pentamethacrylate.

[0070] Based on the total amount of acrylic compounds contained in the active energy ray curable resin composition, the content of acrylic compounds with a molecular weight of 300 or more can be 5% by mass or more, and may be 10% by mass or more, 30% by mass or more, or 50% by mass or more. A content of 5% by mass or more tends to improve gas barrier properties compared to a content of less than 5% by mass. On the other hand, there is no particular upper limit to this content, but it can be 100% by mass.

[0071] When an active energy ray-curable resin composition contains an acrylic compound with a molecular weight of less than 300, the content of the acrylic compound can be 10 to 2000 parts by mass or 50 to 1000 parts by mass per 100 parts by mass of an acrylic compound with a molecular weight of 300 or more. However, if the content is 10 parts by mass or more, the coatability of the composition (coating liquid) tends to improve, and if it is 2000 parts by mass or less, it tends to maintain good gas barrier properties.

[0072] When an active energy ray-curable resin composition contains a carboxyl group-containing acrylic compound with a molecular weight of less than 300, its content can be 10 to 600 parts by mass per 100 parts by mass of an acrylic compound with a molecular weight of 300 or more. However, if the content is 10 parts by mass or more, the coatability and adhesion of the composition (coating liquid) tend to improve, and if it is 600 parts by mass or less, good gas barrier properties tend to be maintained. From the viewpoint of achieving a good balance of coating properties, adhesion, and gas barrier properties, the content of carboxyl group-containing acrylic compounds with a molecular weight of less than 300 is preferably 10 to 600 parts by mass, 10 to 300 parts by mass, 20 to 300 parts by mass, 20 to 200 parts by mass, or 20 to 100 parts by mass per 100 parts by mass of acrylic compounds with a molecular weight of 300 or more.

[0073] When an active energy ray-curable resin composition contains two or more acrylic compounds having an isocyanurate skeleton, the content of hydroxyl group-containing acrylic compounds having an isocyanurate skeleton can be 30% by mass or more, 50% by mass or more, or 70% by mass or more, based on the total amount of acrylic compounds having an isocyanurate skeleton. When the content is 30% by mass or more, the gas barrier properties tend to improve more easily compared to when it is less than 30% by mass. On the other hand, there is no particular upper limit to the content, but it can be 100% by mass.

[0074] From the viewpoint of gas barrier properties, the active energy ray curable resin composition may contain 50% by mass or more of an acrylic compound, and may contain 70% by mass or more, or 80% by mass or more. On the other hand, there is no particular upper limit to the content, but it may be 100% by mass.

[0075] The active energy ray curable resin composition may optionally contain a photoradical generator. Any photoradical generator capable of generating radicals by EB or UV irradiation can be used. The photoradical generator is not particularly limited, but examples include benzyldimethyl ketal, 1-hydroxycyclohexylphenyl ketone, diethylthioxanthone, benzophenone, 2-ethylanthraquinone, 2-hydroxy-2-methylpropiophenone, 2-methyl-[4-(methylthio)phenyl]-2-morpholino-1-propane, 2,4,6-trimethylbenzoyldiphenylphosphate, camphorquinone, 9-fluorenone, and diphenyl disulfide.

[0076] The active energy ray curable resin composition may optionally contain a silane coupling agent. From the viewpoint of EB curability and UV curability, a silane coupling agent having an acryloyl group or a methacryloyl group is preferred. Examples of such silane coupling agents include 3-methacryloyloxypropylmethyldimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropylmethyldiethoxysilane, 3-methacryloyloxypropyltriethoxysilane, and 3-acryloyloxypropyltrimethoxysilane.

[0077] The thickness of the overcoat layer 20 is set according to the required gas barrier properties, and can be, for example, 0.05 to 10 μm, 0.1 to 5 μm, 0.1 to 2 μm, 0.15 to 2 μm, 0.2 to 2 μm, 0.2 to 1.5 μm, 0.2 to 1 μm, or 0.3 to 1 μm. If the thickness of the overcoat layer 20 is 0.05 μm or more, more preferably 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more, sufficient gas barrier properties are easily obtained. On the other hand, from the viewpoint of improving curability (if the thickness is too thick, curing takes a long time) and from the viewpoint of improving adhesion between the overcoat layer and the inorganic oxide layer, the thickness can be 10 μm or less, more preferably 5 μm or less, 1.5 μm or less, or 1 μm or less.

[0078] <Method for manufacturing gas barrier film> The method for manufacturing a gas barrier film is: A process of forming an inorganic oxide layer on a substrate layer, A step of forming a coating film by applying an active energy ray curable resin composition onto an inorganic oxide layer. The process includes a step of curing the coating film by irradiating it with active energy rays to form an overcoat layer, The active energy ray-curable resin composition contains an acrylic compound with a molecular weight of 300 or more.

[0079] An example of a manufacturing procedure for gas barrier films is described below. First, prepare the base layer 10. The base layer 10 may be a commercially available product or may be manufactured by a known method.

[0080] Next, the base layer 30 and the inorganic oxide layer 40, or only the inorganic oxide layer 40, are formed on the base layer 10.

[0081] To form the underlayer 30, for example, an underlayer-forming coating agent can be applied to the base layer 10 by a wet-coat method to form a coating film, and then the coating film can be dried (solvent removed) and hardened. As a method for applying the coating agent, known wet coating methods can be used. Examples of wet coating methods include roll coating, gravure coating, reverse coating, die coating, screen printing, and spray coating. As a method for drying the coating film, known drying methods such as hot air drying, hot roll drying, and infrared irradiation can be used. The drying temperature of the coating film can be, for example, 50 to 200°C. The drying time varies depending on the thickness of the coating film, the drying temperature, etc., but can be, for example, 1 second to 5 minutes. The drying conditions of the coating film should be appropriately determined considering the ease with which the solvent in the coating film dries, the thermal stability of the substrate layer 10, etc.

[0082] The inorganic oxide layer 40 can be formed on the substrate layer 10 or the underlayer 30 by the vacuum deposition method, sputtering method, ion plating method, or plasma vapor deposition (CVD) method described above.

[0083] Next, the overcoat layer 20 is formed. The overcoat layer 20 can be formed, for example, by applying an overcoat layer forming coating agent (the above-mentioned active energy ray curable resin composition) onto the inorganic oxide layer 40 by a wet coating method to form a coating film, and then curing the coating film by EB irradiation or UV irradiation. The irradiation conditions for the active energy rays depend on the thickness of the overcoat layer 20, but the acceleration voltage can be set to 10-300kV and the irradiation dose to 15-120kGy. If the acceleration voltage is within the above range, the active energy rays can easily penetrate sufficiently deep into the thickness direction of the coating film, and the deterioration of the inorganic oxide layer, undercoat layer, substrate layer, etc., by the active energy rays can be easily suppressed. Furthermore, if the irradiation dose is within the above range, it is easy to form the desired cross-linked structure inside the layer while suppressing yellowing and changes in the mechanical properties of the overcoat layer 20. The method for applying the coating agent can be the same as that described in the explanation of the process for forming the base layer 30. The overcoat layer 20 may be formed by a single application and curing, or it may be formed by repeatedly applying and curing the same type of coating agent or different types of coating agents.

[0084] The overcoat layer 20 formed as described above is a cured product of a coating agent (active energy ray curable resin composition) having a crosslinked structure. Here, "having a crosslinked structure" means that the molecular chains of the reactive compound, including the acrylic compound, take on a network-like three-dimensional structure. The presence of the crosslinked structure can be confirmed by various analyses, and analytical methods include Fourier transform infrared spectroscopy, solid-state NMR spectroscopy, X-ray photoelectron spectroscopy, dynamic viscoelasticity measurement, and gel fraction measurement.

[0085] The gas barrier film may be further provided with, if necessary, a printed layer, a protective layer, a light-shielding layer, an adhesive layer, a heat-sealable heat-sealable layer, or other functional layers.

[0086] <Packaging films and packaging materials> The packaging film comprises the aforementioned gas barrier film and a heat-sealable layer provided on the overcoat layer of the gas barrier film. By preparing one or more of these packaging films and heat-sealing the edges with the heat-sealable layers facing each other, a packaging material can be formed. In other words, the packaging material is made by forming a bag from the packaging film.

[0087] Examples of heat-sealable layers include CPP (unoriented polypropylene). The heat-sealable layer can be laminated onto the substrate layer using known adhesives such as polyurethane, polyester, or polyether-based adhesives by known dry lamination methods, extrusion lamination methods, etc.

[0088] By making both the base layer and the heat-sealed layer from polypropylene, the polypropylene content in the packaging film and packaging material can be set to 90% by mass or more. As a result, the packaging film and packaging material become so-called monomaterial materials with excellent recyclability. [Examples]

[0089] The gas barrier films of this disclosure will be further described with reference to examples and comparative examples. This disclosure is not limited in any way by the specific details of the examples and comparative examples.

[0090] (Example 1) [Base material layer preparation] As the base layer 10, a 20 μm thick biaxially oriented polypropylene film (VPH2011, manufactured by AJPlast) was prepared, with one side subjected to corona treatment.

[0091] [Inorganic oxide layer formation] Using a vacuum deposition apparatus with electron beam heating, a mixed material containing two or more types of silicon, including metallic silicon, silicon monoxide, and silicon dioxide, was evaporated to form an inorganic oxide layer 40 (silicon oxide deposition layer) with a thickness of 30 nm on the corona-treated surface of the substrate layer 10.

[0092] [Overcoat layer formation] A coating film was formed on the inorganic oxide layer 40 by applying a coating solution (active energy ray curable resin composition) prepared according to the following procedure using a flexographic printing press. Then, the coating film was cured by EB irradiation using an electron beam irradiation device manufactured by I-Electron Beam, Inc., at an acceleration voltage of 120 kV, an irradiation dose of 15 kGy, and under a nitrogen atmosphere with an oxygen concentration of 100 ppm or less. The thickness of the resulting overcoat layer was 1 μm. This resulted in a gas barrier film having a substrate layer 10 / inorganic oxide layer 40 / overcoat layer 20 in this order. (Procedure for preparing the coating solution) Table 1 shows the acrylic compounds used. In Example 1, tricyclodecanedimethanol diacrylate (product name: Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) was used as the acrylic compound.

[0093] (Examples 2-6 and Comparative Examples 1-3) A gas barrier film was obtained in the same manner as in Example 1, except that the acrylic compounds shown in Table 1 were used. The molecular weight of each compound, the value of formula (1) above, and the presence or absence of an isocyanurate skeleton are also shown in Table 1.

[0094] (Comparative Example 4) A gas barrier film was obtained in the same manner as in Example 1, except that an overcoat layer was not formed.

[0095] The details of the acrylic compounds used are as follows: • 1,6-Hexanediylbis(oxy)bis(2-hydroxy-3,1-propanediyl) bisacrylate (Product name: KAYARAD R-167, manufactured by Nippon Kayaku Co., Ltd.) • 2-Acryloyloxyethyl-2-hydroxyethyl phthalate (Product name: Light Acrylate HOA-MPE(N), manufactured by Kyoeisha Chemical Co., Ltd.) • Bisphenol A diglycidyl ether acrylic acid adduct (Product name: Epoxy Ester 3000A, manufactured by Kyoeisha Chemical Co., Ltd.) Tris(2-hydroxyethyl)isocyanurate triacrylate (product name: A-9300, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) • Tris(2-hydroxyethyl) isocyanurate diacrylate (product name: M-215, manufactured by Toagosei Co., Ltd.) • Butyl acrylate (product name: Butyl Acrylate, manufactured by Tokyo Chemical Industry Co., Ltd.) • Dipropylene glycol diacrylate (product name: Dipropylene Glycol Diacrylate, manufactured by Tokyo Chemical Industry Co., Ltd.) • Neopentyl glycol diacrylate (product name: A-NPG, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)

[0096] [Table 1]

[0097] The following evaluations were performed on the gas barrier films obtained in each example. The results are shown in Table 2.

[0098] (curable) The hardening properties of the gas barrier film's overcoat layer were confirmed by the tackiness felt when rubbing it with a latex glove. A score of ○ was given if no rubbing marks were left on the overcoat layer and no stickiness was detected, while a score of × was given if stickiness was present.

[0099] (Oxygen barrier properties) Using an oxygen permeability measuring device (product name: OXTRAN-2 / 20, manufactured by MOCON), the oxygen permeability (cc / (m³)) of the gas barrier film obtained in each example was measured under an atmosphere of 30°C and 70% RH (relative humidity). 2The temperature (day·atm) was measured. In cases where the curing performance evaluation was negative (×), oxygen barrier performance evaluation was not performed because the stickiness of the overcoat layer surface made handling difficult.

[0100] As shown in Table 2, it is believed that using an acrylic compound with a molecular weight of 300 or more resulted in the formation of a strong coating by active energy ray curing, exhibiting excellent oxygen barrier properties.

[0101] [Table 2]

[0102] In Examples 2-4, where the value of formula (1) was 5 or greater, superior oxygen barrier properties were observed compared to Example 1. This is thought to be because, with a value of formula (1) of 5 or greater, the balance between the improved crosslinking density by acryloyl groups and the interaction within the film by hydroxyl groups improved, resulting in a denser film structure that made it more difficult for oxygen molecules to permeate.

[0103] In Examples 5 and 6, which used acrylic compounds having an isocyanurate skeleton, even better oxygen barrier properties were observed. This is thought to be because acrylic compounds having an isocyanurate skeleton have a relatively high glass transition temperature compared to other acrylic compounds, which suppresses thermal motion in the internal structure of the film, increasing its density and making it more difficult for oxygen molecules to permeate.

[0104] As is clear from Comparative Examples 1 to 3, when acrylic compounds with a molecular weight of less than 300 were used, the curing properties were either insufficient in the first place, or even if the curing properties were sufficient, good oxygen barrier properties could not be obtained.

[0105] (Example 7) As the acrylic compound, tris(2-hydroxyethyl)isocyanurate triacrylate (product name: A-9300, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) (A), which has an isocyanurate skeleton and no hydroxyl groups, and tris(2-hydroxyethyl)isocyanurate diacrylate (product name: M-215, manufactured by Toagosei Co., Ltd.) (B), which has an isocyanurate skeleton and also has hydroxyl groups, were mixed in a mass ratio of A:B = 75:25. Except for this, a gas barrier film was obtained in the same manner as in Example 1.

[0106] (Examples 8-10) A gas barrier film was obtained in the same manner as in Example 7, except that the mass ratio of A and B was changed as shown in Table 3.

[0107] [Table 3]

[0108] Even when two different isocyanurate skeleton compounds were mixed as acrylic compounds, excellent oxygen barrier properties were observed. In particular, in Examples 8 to 10, where compound (B) containing hydroxyl groups was 30% by mass or more, superior oxygen barrier properties were shown compared to Example 7. This is thought to be because the presence of hydroxyl groups, which have a high affinity for oxygen molecules, in the coating containing the isocyanurate skeleton further suppressed the diffusion of oxygen molecules.

[0109] (Example 11) As the acrylic compound, tris(2-hydroxyethyl)isocyanurate diacrylate (product name: M-215, manufactured by Toagosei) (C) and glycerin diacrylate (product name: M-920, manufactured by Toagosei, molecular weight 200) (D) were mixed in a mass ratio of C:D = 70:30. Except for this, a gas barrier film was obtained in the same manner as in Example 1. The viscosities shown in Table 4 are those of the coating liquid at a shear rate of 100 (1 / s), measured continuously from a shear rate of 1 (1 / s) to 1000 (1 / s) using a rheometer (HAAKE MARS, manufactured by Thermo Scientific) at a temperature of 23°C and a cone plate (diameter 60 mm, cone angle 1°).

[0110] (Examples 12-14) A gas barrier film was obtained in the same manner as in Example 11, except that the mass ratio of C and D was changed as shown in Table 4.

[0111] (Example 15) As the acrylic compound, tris(2-hydroxyethyl)isocyanurate diacrylate (product name: M-215, manufactured by Toagosei Co., Ltd.) (C) and 1-(acryloyloxy)-3-(methacryloyloxy)-2-propanol (product name: 1-(Acryloyloxy)-3-(methacryloyloxy)-2-propanol, manufactured by Tokyo Chemical Industry Co., Ltd., molecular weight 214) (E) were mixed in a mass ratio of C:E = 70:30. Except for this, a gas barrier film was obtained in the same manner as in Example 1.

[0112] (Examples 16-18) A gas barrier film was obtained in the same manner as in Example 15, except that the mass ratio of C and E was changed as shown in Table 4.

[0113] [Table 4]

[0114] By combining acrylic compounds with a molecular weight of 300 or more, which have excellent oxygen barrier properties, with low-viscosity acrylic compounds, it is possible to improve the coatability of the coating solution while maintaining excellent oxygen barrier properties. By adjusting the viscosity of the coating solution without using solvents, a heat drying process for the coating film becomes unnecessary, and it is possible to suppress dimensional changes in the base film and the resulting crack formation in the inorganic oxide layer.

[0115] (Example 19) As the acrylic compound, a mixture of 2-acryloyloxyethyl-2-hydroxyethyl phthalic acid (product name: Light Acrylate HOA-MPE(N), manufactured by Kyoeisha Chemical Co., Ltd.) (F) and 2-acryloyloxyethyl succinic acid (product name: Light Acrylate HOA-MS(N), manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 216) (G) was used, in a mass ratio of F:G = 50:50. Except for this, a gas barrier film was obtained in the same manner as in Example 1.

[0116] (Example 20) Instead of G, 2-acryloyloxyethyl hexahydrophthalic acid (product name: Light Acrylate HOA-HH(N), manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 270) (H) was used. Except for this, a gas barrier film was obtained in the same manner as in Example 19.

[0117] (Example 21) Instead of G, 2-acryloyloxyethyl phthalic acid (product name: M-5400, manufactured by Toagosei, molecular weight 264) (I) was used. Except for this, a gas barrier film was obtained in the same manner as in Example 19.

[0118] (Example 22) As the acrylic compound, a mixture of 2-acryloyloxyethyl succinic acid (product name: Light Acrylate HOA-MS(N), manufactured by Kyoeisha Chemical Co., Ltd., molecular weight 216) (G) and tris(2-hydroxyethyl)isocyanurate diacrylate (product name: M-215, manufactured by Toagosei Co., Ltd.) (J) was used, in a mass ratio of G:J = 70:30. Except for this, a gas barrier film was obtained in the same manner as in Example 1.

[0119] (Example 23) A gas barrier film was obtained in the same manner as in Example 22, except that a mixture with a mass ratio of G:J = 85:15 was used.

[0120] (Adhesion) The adhesion between the overcoat layer and the inorganic oxide layer was evaluated using the "X-cut tape method" of JIS K 5400. In this method, a thin cross-shaped cut is made in the overcoat layer with a cutter, cellophane tape is applied over the cut, and the degree of the overcoat layer remaining on the film after the tape is peeled off is observed. A circle (○) indicates that the overcoat layer did not peel off at all, and a cross (×) indicates that even a small amount peeled off.

[0121] [Table 5]

[0122] As shown in Table 5, the adhesion test results for Examples 19-23 were all good. By using acrylic compounds with a molecular weight of 300 or more that have excellent oxygen barrier properties, along with carboxyl group-containing acrylic compounds with a molecular weight of less than 300, a synergistic effect was demonstrated in improving the adhesion between the overcoat layer and the inorganic oxide layer, as well as the oxygen barrier properties.

[0123] While embodiments and examples of the present disclosure have been described above, the specific configuration of the present disclosure is not limited to those described above, and modifications, combinations, etc., of the configuration are possible within the scope of the gist of the present disclosure. [Explanation of symbols]

[0124] 10...Base layer, 20...Overcoat layer, 30...Undercoat layer, 40...Inorganic oxide layer, 100, 200...Gas barrier film.

Claims

1. A process of forming an inorganic oxide layer on a substrate layer, The process involves applying an active energy ray-curable resin composition onto the inorganic oxide layer to form a coating film, The process includes a step of curing the aforementioned coating film by irradiating it with active energy rays to form an overcoat layer, A method for producing a gas barrier film, wherein the active energy ray curable resin composition contains an acrylic compound with a molecular weight of 300 or more.

2. The material comprises a base layer, an inorganic oxide layer, and an overcoat layer in this order. The overcoat layer is a cured product of an active energy ray curable resin composition having a crosslinked structure. The aforementioned active energy ray-curable resin composition comprises an acrylic compound with a molecular weight of 300 or more, and is a gas barrier film.

3. The gas barrier film according to claim 2, wherein the active energy ray curable resin composition comprises the acrylic compound having an isocyanurate skeleton.

4. The gas barrier film according to claim 3, wherein the active energy ray curable resin composition comprises two or more types of acrylic compounds having an isocyanurate skeleton.

5. The gas barrier film according to claim 3, wherein the content of the hydroxyl group-containing acrylic compound having an isocyanurate skeleton is 30% by mass or more, based on the total amount of the acrylic compound having an isocyanurate skeleton.

6. The gas barrier film according to claim 2, wherein the active energy ray curable resin composition further comprises an acrylic compound having a molecular weight of less than 300.

7. The gas barrier film according to claim 2, wherein the active energy ray curable resin composition further comprises a carboxyl group-containing acrylic compound having a molecular weight of less than 300.

8. The gas barrier film according to claim 2, wherein the base layer contains a polyolefin resin.

9. The gas barrier film according to claim 2, wherein the thickness of the overcoat layer is 0.15 to 2 μm.

10. A packaging film comprising a gas barrier film according to any one of claims 2 to 9, and a heat-sealable layer provided on the overcoat layer of the gas barrier film.

11. A packaging material made by forming a bag from the packaging film described in claim 10.

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