Multilayer film and laminate film

Abstract

To provide a laminated film which is an environment-conscious film having a resin layer composed of a polyolefin base material and has high gas barrier properties and good gas barrier properties even after the elapse of time, and a laminated film.SOLUTION: The laminated film has a resin layer (B) and an inorganic layer (C) adjacent to the resin layer (B) on at least one surface of a base material film (A), wherein the resin layer (B) contains a reaction product of a polyurethane resin, a silane coupling agent and an organic salt.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a gas barrier laminate film and a laminate film. [Background technology]

[0002] Due to the recent increase in awareness of environmental issues, there is a demand for easily recyclable materials for flexible packaging used for food, pharmaceuticals, industrial goods, etc.

[0003] There are various approaches to developing recyclable flexible packaging materials, but polyolefins, which have low melting points and good sealing properties, are often used to make it easier to bond films together during bag production, which has led to increased demand for polyolefin substrates. At the same time, achieving high gas barrier properties is also important in order to utilize long-life technology to reduce food waste.

[0004] Various underlayers have been investigated to improve the adhesion of vapor-deposited films to polyolefin substrates. It is known that the provision of an underlayer made of polyurethane resin provides high gas barrier properties.

[0005] For example, Patent Document 1 describes a gas barrier film comprising a resin substrate, an underlayer, and a vacuum-deposited layer, in which the resin substrate contains a polyolefin resin and the underlayer contains a polyurethane resin formed from an acid group-containing polyurethane and a polyamine. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2022 / 220200 Summary of the Invention [Problem to be solved by the invention]

[0007] However, it cannot be said that this has yet fully satisfied the demand for even higher gas barrier properties, particularly for gas barrier properties that remain good even after aging. Therefore, an object of the present invention is to provide a laminate film and a multilayer film that are environmentally friendly films that include a resin layer made of a polyolefin substrate, and that have high gas barrier properties and that remain good gas barrier properties even after aging. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by the following configuration. The present invention comprises the following configurations.

[0009] [1] A laminate film having a resin layer (B) and an inorganic layer (C) adjacent to the resin layer (B) on at least one side of a base film (A), wherein the laminate film contains a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt. [2] The laminated film according to [1], wherein the base film (A), the resin layer (B), and the inorganic layer (C) adjacent to the resin layer (B) are laminated in this order. [3] The laminated film according to [1], in which the base film (A), an inorganic layer (C) adjacent to the resin layer (B), and the resin layer (B) are laminated in this order. [4] The laminated film according to any one of [1] to [3], wherein the resin layer (B) contains a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt. [5] The laminated film according to [4], wherein the reaction product in the resin layer (B) is a polymer containing a urethane bond, a trisiloxy unit, and a unit derived from bismethylenecyclohexane. [6] Water vapor permeability of 1g / m at 40°C and 90% relative humidity 2 The laminated film according to any one of [1] to [5], wherein the life span is 10 days or less. [7] The laminated film according to any one of [1] to [6], wherein the base film (A) is a polyolefin-based resin film. [8] The laminated film according to any one of [1] to [7], wherein the base film (A) is a polypropylene-based resin film. [9] The laminated film according to any one of [1] to [8], wherein the base film (A) is a film stretched in at least one direction.

[10] The laminated film according to any one of [1] to [9], wherein the organic salt is an alkali metal salt of an organic acid.

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

[10] , wherein the organic salt is tripotassium citrate monohydrate.

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

[11] , wherein the resin layer (B) contains a resin having a silicon compound in which citric acid and an epoxy group have reacted with a polymer skeleton.

[13] The laminated film according to any one of

[10] to

[12] , wherein the content of alkali metals contained in the entire laminated film is 0.00005% by mass or more and 0.5% by mass or less.

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

[13] , wherein the resin layer (B) has a thickness of 0.1 μm or more and 20 μm or less.

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

[14] , wherein the inorganic layer (C) has a thickness of 5 nm or more and 200 nm or less.

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

[15] , wherein when the laminated film is stored at a temperature of 40°C and a relative humidity of 90%, the ratio ((II) / (I)) of the water vapor permeability (I) after 1 day to the water vapor permeability (II) after 14 days is 0.7 or less.

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

[16] , which is used for food packaging.

[18] A laminate film obtained by laminating the laminate film according to any one of [1] to

[17] and a polyolefin resin layer.

[19] The laminate film according to

[18] , which is used for food packaging. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a laminate film and a multilayer film that have high gas barrier properties and maintain good gas barrier properties even after aging. In particular, a laminate film that uses a polyolefin-based film as a base film and has a polyolefin resin layer laminated thereon as a sealant layer can be used as an environmentally friendly film made of a monomaterial that is easy to recycle. DETAILED DESCRIPTION OF THE INVENTION

[0011] Next, an example of an embodiment of the present invention will be described, but the present invention is not limited to the embodiment described below.

[0012] [Laminated film] The laminate film of the present invention has a resin layer (B) and an inorganic layer (C) adjacent to the resin layer (B) on at least one surface of a base film (A), and the laminate film contains a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt. That is, the laminated film has a resin layer (B) and an inorganic layer (C) adjacent to the resin layer (B) on one side of a base film (A), or has a resin layer (B) and an inorganic layer (C) adjacent to the resin layer (B) on both sides of a base film (A). An adhesive layer or the like may be interposed between the base film (A) and the resin layer (B).

[0013] The laminate film of the present invention preferably comprises a base film (A), a resin layer (B), and an inorganic layer (C) adjacent to the resin layer (B) laminated in this order. That is, the laminate film may have the resin layer (B) and the inorganic layer (C) in this order on one side of the base film (A), or the resin layer (B) and the inorganic layer (C) in this order on both sides of the base film (A).

[0014] The laminate film of the present invention preferably comprises a base film (A), an inorganic layer (C) adjacent to the resin layer (B), and the resin layer (B) laminated in this order. That is, the laminate film may have the inorganic layer (C) and the resin layer (B) in this order on one side of the base film (A), or the inorganic layer (C) and the resin layer (B) in this order on both sides of the base film (A).

[0015] In the present invention, the term "film" includes the term "sheet", and the term "sheet" includes the term "film". Furthermore, when it is written as "X to Y" (X and Y are any numbers), unless otherwise specified, it means "X or more and Y or less," and also means "preferably greater than X" or "preferably smaller than Y." When it is written as "X or more" (X is any number), it means "preferably greater than X" unless otherwise specified, and when it is written as "Y or less" (Y is any number), it also means "preferably smaller than Y" unless otherwise specified.

[0016] Next, the laminated film will be explained, which comprises the substrate film (A), the resin layer (B) and the inorganic layer (C).

[0017] [Base film (A)] The material of the base film (A) is not limited as long as it has good gas barrier properties, but a polyolefin resin film is preferred from the viewpoint of being an easily recyclable material. Gas barrier properties refer to the impermeability of oxygen and water vapor, and in the present invention, particularly refers to the impermeability of water vapor.

[0018] Examples of polyolefin resins include homopolymers or copolymers obtained by polymerizing α-olefins such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. Two or more of the above homopolymers or copolymers may be mixed and used. Among these, polypropylene-based resins or polyethylene-based resins are preferred from the viewpoint of formability into a film. Among these, polypropylene-based resins are more preferred from the viewpoint of heat resistance when formed into a film. That is, it is more preferred that the base film (A) is a polypropylene-based resin film. Examples of the polypropylene-based resin include propylene homopolymers, random copolymers, and block copolymers. Among these, when heat resistance is required for the base film (A), propylene homopolymers are preferred. If the main component resin of the base film (A) is a propylene homopolymer, the laminate film of the present invention can be made to withstand heat sterilization treatments such as boiling treatment and retort treatment.

[0019] The polyolefin resin may contain additives such as antistatic agents, ultraviolet absorbers, plasticizers, and lubricants, as needed.

[0020] The polyolefin resin may contain a combination of a polypropylene resin and a polyolefin resin other than a polypropylene resin (hereinafter also referred to as "other polyolefin resin").

[0021] Examples of "other polyolefin resins" include polymers of olefin monomers such as ethylene, 1-butene, 4-methyl-1-pentene, and hexene, as well as copolymers of the above olefin monomers with other monomers. Specific examples include polyethylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer, ethylene-methyl (meth)acrylate copolymer, and ionomer resin. Among these, polyethylene is preferred from the viewpoint of formability into a film.

[0022] In addition to the "other polyolefin resins," the polyolefin resin may contain "other resins" such as polyamide resins, polystyrene resins, and polyester resins, as long as the effects of the present invention are not impaired.

[0023] However, from the viewpoint of achieving high mechanical properties, heat resistance, and the mono-materialization of the laminated film of the present invention and packaging materials using the same, the content of "other resins" is preferably 40% by mass or less, more preferably 20% by mass or less, even more preferably 10% by mass or less, and still more preferably 5% by mass or less, based on the total resin components of the polyolefin-based resin film. It is particularly preferable that all resin components of the polyolefin-based resin film are polyolefin-based resins, and most preferably that the polyolefin-based resin is a polypropylene-based resin.

[0024] The polyolefin resin film may contain particles mainly for the purpose of roughening the film surface to impart slipperiness and preventing scratches from occurring in each process.

[0025] The type of the particles is not particularly limited as long as they are particles that can impart lubricity. Examples include inorganic particles such as silica, calcium carbonate, magnesium carbonate, barium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, kaolin, aluminum oxide, and titanium oxide, and organic particles such as acrylic resin, styrene resin, urea resin, phenolic resin, epoxy resin, and benzoguanamine resin. These may be used alone or in combination of two or more.

[0026] The shape of the particles is not particularly limited, and may be, for example, spherical, blocky, rod-like, flat, or the like. There are no particular limitations on the hardness, specific gravity, color, etc. of the particles. Two or more types of these particles may be used in combination as needed.

[0027] The average particle size of the particles is preferably 5 μm or less, more preferably 0.01 μm or more and 3.0 μm or less, and even more preferably 0.5 μm or more and 2.5 μm or less. When the average particle size of the particles is 5 μm or less, the surface roughness of the polyolefin resin film is not too large, and problems occurring when forming the inorganic layer (C) on the surface of the base film (A) can be reduced.

[0028] The particle content is preferably 5% by mass or less, more preferably 0.0003% by mass or more and 3% by mass or less, and even more preferably 0.01% by mass or more and 2% by mass or less, relative to the mass (100% by mass) of the polyolefin resin film. By setting the particle content within this range, it is possible to achieve both smoothness and transparency of the film.

[0029] In addition, from the viewpoint of achieving a high degree of mono-materiality in the laminated film of the present invention, the mass ratio of the polyolefin resin in the polyolefin resin film (100 mass%) is preferably 60 mass% or more, more preferably 80 mass% or more, and even more preferably 90 mass% or more.

[0030] The content of the "other polyolefin resin" in the polyolefin resin film is not particularly limited, but from the viewpoint of achieving a high degree of monomateriality in the laminate film of the present invention, it is preferably 40% by mass or less, more preferably 20% by mass or less, and even more preferably 10% by mass or less.

[0031] The substrate film (A) may have a single layer structure or a laminated (multilayer) structure. In the case of a laminated structure, it may have two or three layers, or may have four or more layers without departing from the gist of the present invention. The number of layers to be laminated is not particularly limited, but is preferably 10 or less. If there are 10 or less layers, each layer will have a sufficient thickness, resulting in sufficient lamination during film formation, making it less likely for flow marks and the like to occur, and ensuring sufficient film quality. In the case of a laminated structure, two kinds of three layers or three kinds of three layers are preferred.

[0032] The substrate film (A) may be either an unstretched film or a stretched film. From the viewpoints of mechanical strength and moisture resistance, a film stretched in at least one direction is preferred, a uniaxially or biaxially stretched film is more preferred, and a biaxially stretched film is even more preferred from the viewpoints of excellent balance of mechanical properties, flatness, and moisture resistance.

[0033] The substrate film (A) can be formed by melt-extruding a resin composition containing a polyolefin resin into a film shape by a general molding method such as melt extrusion molding or heat pressing, but is not limited to this method.

[0034] The thickness of the base film (A) is not particularly limited as long as it is within a range that allows it to be formed into a film, but from the viewpoints of gas barrier properties and cost, it is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 30 μm or less.

[0035] From the viewpoints of mechanical strength and moisture resistance, the base film (A) is preferably a film stretched in at least one direction, and from the viewpoints of transparency and heat resistance in addition to mechanical strength and moisture resistance, it is more preferably a biaxially stretched film.

[0036] [Resin layer (B)] The resin layer (B) according to the present invention serves as an anchor coat layer for improving gas barrier properties, adhesion between the base film (A) and the inorganic layer (C), and smoothness of the base film (A).

[0037] (Polyurethane resin) The polyurethane resin used in the present invention serves as a binder. The polyurethane resin is obtained by a urethane reaction between a polyisocyanate component, a polyol component, and, if necessary, a polyamine component.

[0038] Examples of the polyisocyanate component include aromatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, and aliphatic diisocyanates.

[0039] Examples of aromatic diisocyanates include m- or p-phenylene diisocyanate or a mixture thereof, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), 4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or a mixture thereof (MDI), 2,4- or 2,6-tolylene diisocyanate or a mixture thereof (TDI), 4,4'-toluidine diisocyanate (TODI), and 4,4'-diphenyl ether diisocyanate.

[0040] Examples of the aromatic aliphatic diisocyanate include 1,3- or 1,4-xylylene diisocyanate or a mixture thereof (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate or a mixture thereof (TMXDI), and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0041] Examples of alicyclic diisocyanates include 1,3-cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate; IPDI), 4,4'-, 2,4'-, or 2,2'-dicyclohexylmethane diisocyanate or mixtures thereof (hydrogenated MDI), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or mixtures thereof (hydrogenated XDI), and the like.

[0042] Examples of aliphatic diisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-, 2,3-, or 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and methyl 2,6-diisocyanatocaproate.

[0043] Of these diisocyanate components, preferred aromatic diisocyanates include, for example, TDI, MDI, NDI, etc., preferred aromatic-aliphatic diisocyanates include, for example, XDI, TMXDI, etc., preferred alicyclic diisocyanates include, for example, IPDI, hydrogenated XDI, hydrogenated MDI, etc., and preferred aliphatic diisocyanates include, for example, HDI, etc. From the viewpoint of gas barrier properties, aromatic diisocyanates (TDI, MDI, NDI, etc.), aromatic-aliphatic diisocyanates (XDI, TMXDI, etc.), and alicyclic diisocyanates (IPDI, hydrogenated XDI, hydrogenated MDI, etc.), particularly aromatic diisocyanates (MDI, etc.), aromatic-aliphatic diisocyanates (XDI, etc.), and alicyclic diisocyanates (hydrogenated XDI, etc.) are preferred. Furthermore, in a diisocyanate component having a substituent on the ring, it is preferable that the side chain of the aromatic ring or alicyclic ring is a short chain (e.g., a C1-3 alkyl group), and it is preferable that the diisocyanate component has a symmetric structure. As the polyisocyanate, at least one selected from xylylene diisocyanate and hydrogenated xylylene diisocyanate is particularly preferable.

[0044] These diisocyanate components can be used alone or in combination of two or more. Furthermore, tri- or higher functional polyisocyanates can also be used in combination, if necessary.

[0045] The polyol component includes a wide range of diols from low molecular weight diols to oligomers, for example, C2-12 alkylene glycols (e.g., ethylene glycol, 1,3- or 1,2-propylene glycol, 1,4-, 1,3- or 1,2-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2,2,4-trimethylpentane-1,3-diol, 1,6-hexamethylpentane ... polyether diols such as polyoxy C2-4 alkylene glycols (e.g., diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, hexaethylene glycol, heptaethylene glycol, octanediol, neopentyl glycol, 1,5- or 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc.); Examples of the diol component include low-molecular-weight diol components such as ethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, hexapropylene glycol, heptapropylene glycol, dibutylene glycol, tributylene glycol, and tetrabutylene glycol), aromatic diols (for example, bisphenol A, bishydroxyethyl terephthalate, catechol, resorcinol, hydroquinone, 1,3- or 1,4-xylylenediol, or mixtures thereof), and alicyclic diols (for example, hydrogenated bisphenol A, hydrogenated xylylenediol, cyclohexanediol, and cyclohexanedimethanol), polyester diols (for example, addition reaction products of the above-mentioned low-molecular-weight diols and lactones, and reaction products of the above-mentioned low-molecular-weight diols and dicarboxylic acids), and polycarbonate diols (for example, reaction products of the above-mentioned low-molecular-weight diols and short-chain dialkyl carbonates).

[0046] The molecular weight of the diol component is preferably 50 to 600, more preferably 50 to 300, and even more preferably 60 to 200 or so.

[0047] Of these diol components, from the viewpoint of gas barrier properties, low molecular weight diol components such as C2-8 diols (e.g., ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, etc.), and preferably C2-6 diols (particularly ethylene glycol, 1,2- or 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc.) are used.

[0048] These diol components can be used alone or in combination of two or more. Furthermore, tri- or higher functional polyol components can also be used in combination, if necessary.

[0049] If necessary, a polyamine component can be used as a chain extender or crosslinker. Examples of polyamines include hydrazine, aliphatic diamines (e.g., ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2,2,4-trimethylhexamethylenediamine, 2,4,4-trimethylhexamethylenediamine, and octamethylenediamine), aromatic amines (e.g., m- or p-phenylenediamine, 1,3- or 1,4-xylylenediamine, or a mixture thereof), and alicyclic diamines (e.g., hydrogenated xylylenediamine, bis(4-aminocyclohexyl)methane, isophoronediamine, and bis(4-amino-3-methylcyclohexyl)methane). Other examples include diamines having a hydroxyl group, such as 2-hydrazinoethanol and 2-[(2-aminoethyl)amino]ethanol.

[0050] Of these diamine components, from the viewpoint of gas barrier properties, preferably low-molecular-weight diamine components having 8 or less carbon atoms are used, and more preferably diamines having 6 or less carbon atoms (particularly, hydrazine, ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, 2-hydrazinoethanol, 2-[(2-aminoethyl)amino]ethanol, etc.).

[0051] These diamine components can be used alone or in combination of two or more. Furthermore, tri- or higher functional polyamine components can also be used in combination, if necessary.

[0052] A typical urethane reaction using an organic solvent can be used to produce a polyurethane resin. The organic solvent is not particularly limited as long as it can dissolve the polyurethane resin and is inert to the reaction. Examples of the organic solvent include ethers (tetrahydrofuran, dioxane, etc.), ketones (acetone, methyl ethyl ketone, etc.), aromatic hydrocarbons (toluene, xylene, etc.), nitriles (acetonitrile, etc.), carbonates (dimethyl carbonate, diethyl carbonate, etc.), amides (dimethylformamide, dimethylacetamide, etc.), and sulfoxides (dimethyl sulfoxide, etc.). These organic solvents can be used alone or in combination. In the urethanization reaction, a urethanization catalyst such as an amine-based catalyst, a tin-based catalyst, or a lead-based catalyst may be used as needed.

[0053] The ratio of the diisocyanate component to the diol component (when a diamine component is used, the ratio of the diisocyanate component to the total of the diol component and the diamine component) can be selected from the range of about 0.5 to 1.5 mol, preferably 0.7 to 1.3 mol, and more preferably 0.85 to 1.15 mol of the diol component (diol component and diamine component) per 1 mol of diisocyanate.

[0054] The polyurethane resin may be in the form of either a solution dissolved in the organic solvent or an aqueous solution, or may be in the form of an aqueous dispersion of the polyurethane resin (aqueous dispersion). The aqueous dispersion can be prepared by emulsifying and dispersing a polyurethane prepolymer and extending the chains with a chain extender such as a diamine component.

[0055] When the polyurethane prepolymer does not have a hydrophilic group, an aqueous dispersion can usually be prepared by emulsifying the polyurethane prepolymer with an emulsifier and extending the chains with a chain extender.

[0056] Examples of emulsifiers include water-soluble polymer-type protective colloids such as polyvinyl alcohol, cellulose derivatives (e.g., carboxymethyl cellulose), gelatin, and dextrin; nonionic surfactants such as polyoxyethylene C8-20 alkylphenyl ethers such as polyoxyethylene nonylphenyl ether and polyoxyethylene-oxypropylene block copolymers; and anionic surfactants such as alkali metal C8-20 alkyl sulfates such as sodium lauryl sulfate and alkali metal C8-20 alkylbenzene sulfonates such as sodium dodecylbenzenesulfonate.

[0057] The amount of emulsifier used, in terms of solid content, is preferably 0.1 to 20 parts by mass, more preferably 1 to 20 parts by mass, even more preferably 1 to 15 parts by mass, and even more preferably about 3 to 10 parts by mass per 100 parts by mass of polyurethane prepolymer.

[0058] When the polyurethane prepolymer has hydrophilic groups, for example, a hydrophilic compound is used as at least a part of the diol component (or diamine component) and reacted with an isocyanate compound to introduce the hydrophilic groups into the polyurethane prepolymer. The polyurethane prepolymer is then dispersed in water and chain-extended using a chain extender such as a diamine component to prepare an aqueous dispersion. Examples of hydrophilic groups include ionic dissociation groups (e.g., carboxyl groups, sulfonic acid groups, sulfonate groups, carbamoylsulfonate groups, quaternary amino groups, or quaternary ammonium salts), nonionic groups (e.g., polyoxyalkylene groups (e.g., polyoxyethylene groups), epoxy groups), etc. Among these hydrophilic groups, anionic groups (e.g., carboxyl groups, sulfonic acid groups, sulfonate groups, carbamoylsulfonate groups), nonionic groups (polyoxyethylene groups), and especially anionic groups (e.g., carboxyl groups and sulfonic acid groups) are preferred. In order to dissolve or disperse a prepolymer into which an anionic hydrophilic group such as a carboxyl group or a sulfonic acid group has been introduced, it is preferable to neutralize the anionic group with a neutralizing agent before chain extension.

[0059] The hydrophilic compound has in its molecule a hydrophilic group and a group reactive with an isocyanate group, such as a hydroxyl group, an amino group, or a mercapto group. Examples of hydrophilic compounds include compounds having a carboxyl group, such as dihydroxycarboxylic acids (e.g., dihydroxy C2-10 carboxylic acids such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid, dihydroxy C4-10 polycarboxylic acids such as dioxymaleic acid, and dihydroxy aromatic carboxylic acids such as 2,6-dihydroxybenzoic acid), diaminocarboxylic acids (e.g., diamino aromatic carboxylic acids such as 3,4-diaminobenzoic acid), and reaction products of acid anhydrides (e.g., maleic anhydride, phthalic anhydride, succinic anhydride, trimellitic anhydride, and pyromellitic anhydride) with compounds having a reactive group to an isocyanate group (dihydroxy compounds such as diols, diamines, etc.), and oligoesters obtained by copolymerizing these compounds having a carboxyl group. Examples of suitable hydrophilic compounds include terpolyols; compounds having a sulfonic acid group, such as oxysulfonic acids (e.g., 2-oxyethanesulfonic acid, phenolsulfonic acid, etc.), sulfocarboxylic acids (e.g., sulfobenzoic acid, sulfosuccinic acid, 5-sulfoisophthalic acid, etc.), and amino-group-containing sulfonic acids (e.g., sulfanilic acid, 1,3-phenylenediamine-4,6-disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid), or oligoester polyols obtained by copolymerizing such compounds having a sulfonic acid group; and polyoxy C2-4 alkylene compounds having a group reactive with an isocyanate group (e.g., compounds containing 30% or more by mass of ethylene oxide units and having a number average molecular weight of about 300 to 10,000), or oligoester ether polyols obtained by copolymerizing such polyoxyalkylene compounds. These hydrophilic compounds can be used singly or in combination of two or more.

[0060] The proportion of the hydrophilic compound can be selected from the range of about 1 to 100 mol %, preferably 5 to 70 mol %, more preferably 5 to 50 mol %, and even more preferably 10 to 40 mol % of the diol component and / or diamine component.

[0061] The neutralizing agent can be selected depending on the type of hydrophilic group, and when the hydrophilic group is an anionic group, examples include inorganic bases (for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkaline earth metal hydroxides such as calcium hydroxide and magnesium hydroxide, alkali metal carbonates such as sodium carbonate and potassium carbonate, alkali metal bicarbonates such as sodium bicarbonate, ammonia, etc.), organic bases (mono-, di-, or tri-C alkylamines such as trimethylamine and triethylamine, mono-, di-, or tri-C alkanolamines such as monoethanolamine, diethanolamine, triethanolamine, etc.), etc. These neutralizing agents can be used alone or in combination of two or more.

[0062] From the viewpoint of gas barrier properties, water resistance, etc., the aqueous dispersion of the polyurethane resin is preferably a dispersion of a soap-free resin that does not contain a free surfactant (for example, a resin obtained by dispersing a prepolymer into which the hydrophilic group has been introduced and then chain-extending the prepolymer).

[0063] The solvent for the aqueous dispersion is not limited to water alone, but may also be a mixed solvent of water and a water-soluble solvent (for example, a C1-4 alcohol such as methanol, ethanol, or isopropanol, a ketone such as acetone, or a cellosolve). In preparing the aqueous dispersion, the organic solvent can be replaced with water by a conventional solvent replacement method, for example, a method in which the organic solvent is distilled off and replaced with water.

[0064] The polyurethane resin preferably has a total urethane group concentration and urea group concentration of 15% by mass or more, more preferably 20% by mass or more, for example, about 20 to 60% by mass, preferably 30 to 60% by mass, more preferably 35 to 60% by mass, and even more preferably 35 to 55% by mass. By making the total urethane group concentration and urea group concentration 15% by mass or more, the cohesive strength of the resin can be increased, and good gas barrier properties can be exhibited.

[0065] The urethane group concentration and urea group concentration are values ​​obtained by dividing the molecular weight of the urethane group (59 g / equivalent) or the molecular weight of the urea group (58 g / equivalent) by the molecular weight of the repeating structural unit structure.

[0066] The repeating units of the polyurethane resin preferably contain aromatic or non-aromatic hydrocarbon ring units, for example, aromatic or alicyclic compound units, and these aromatic or alicyclic compounds are usually derived from diisocyanate components, but may also be derived from diol components. The proportion of hydrocarbon ring units in the repeating units of the polyurethane resin is preferably about 10 to 70 mass%, more preferably about 15 to 65 mass%, and even more preferably about 20 to 60 mass%.

[0067] The polyurethane resin suitably contains repeating units consisting of a diisocyanate component (particularly, an aromatic diisocyanate) and a diol component (particularly, a C2-8 alkylene glycol) in an amount of 30 mol % or more, preferably 50 mol % or more, and more preferably 70 mol % or more of all constituent units. Note that, in this case, similar effects can be obtained by using an aromatic diol (or diamine) such as xylylene diol (or diamine) as the diol component (or diol and diamine component) and a low-molecular-weight diisocyanate such as HDI as the diisocyanate component.

[0068] The polyurethane resin may have either a hydroxyl group or an isocyanate group at the end. Hydroxyl groups are suitable for use as thermoplastic molding materials, while isocyanate groups improve adhesion when coated onto plastic substrates and also enable post-curing due to moisture.

[0069] The number-average molecular weight (Mn) of the polyurethane resin can be selected from the range of preferably 1 million to 5 million, more preferably 1 million to 3 million, and even more preferably about 1 million to 2 million. A number-average molecular weight of 1 million or more is preferred because sufficient strength can be obtained when used as a molded product such as a film. Furthermore, when coating a silicon oxide layer, the polyurethane resin itself has cohesive strength, facilitating film formation. On the other hand, a number-average molecular weight of 5 million or less is preferred because the viscosity of the polyurethane resin can be kept low even in a solvent, improving coating and lamination workability.

[0070] Polyurethane resins with a high degree of crystallinity have excellent gas barrier properties. The glass transition point of the polyurethane resin is preferably 90°C or higher, more preferably 110°C or higher, and even more preferably 115°C or higher, for example, about 90 to 200°C, preferably about 110 to 180°C, and more preferably about 115 to 180°C. By increasing the glass transition point to 90°C or higher, the gas barrier properties can be improved.

[0071] In addition to polyurethane resin, the binder may, if necessary, be (meth)acrylic resin, polyester resin, polyvinyl resin (such as polyvinyl alcohol or vinyl chloride-vinyl acetate copolymer), polyalkylene glycol, polyalkyleneimine, methyl cellulose, hydroxy cellulose, starch, etc. One type of binder resin may be used alone, or two or more types may be used in combination.

[0072] (Silane coupling agent) The silane coupling agent is a crosslinking agent and plays a role of crosslinking the polyurethane resin as a binder. Examples of the silane coupling agent according to the present invention include hydrolyzable alkoxysilane compounds, such as halogen-containing alkoxysilanes; chloro C2-4 alkyl tri C1-4 alkoxysilanes such as 2-chloroethyl trimethoxysilane, 2-chloroethyl triethoxysilane, 3-chloropropyl trimethoxysilane, and 3-chloropropyl triethoxysilane; alkoxysilanes having an epoxy group; 2-glycidyloxyethyl trimethoxysilane, 2-glycidyloxyethyl triethoxysilane, 3-glycidyloxypropyl trimethoxysilane, and 3-glycidyloxypropyl triethoxysilane. alkoxysilanes having an amino group, such as glycidyloxy C2-4 alkyltriC1-4 alkoxysilanes such as methylsilane, glycidyloxydiC2-4 alkyldiC1-4 alkoxysilanes such as 3-glycidyloxypropylmethyldimethoxysilane and 3-glycidyloxypropylmethyldiethoxysilane, and (epoxycycloalkyl)C2-4 alkyltriC1-4 alkoxysilanes such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane and 3-(3,4-epoxycyclohexyl)propyltrimethoxysilane;Amino C2-4 alkyltriC1-4 alkoxysilanes such as 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropyltriethoxysilane; amino diC2-4 alkyldiC1-4 alkoxysilanes such as 3-aminopropylmethyldimethoxysilane and 3-aminopropylmethyldiethoxysilane; 2-[N-(2-aminoethyl)amino]ethyltrimethoxysilane, 3-[N-(2-aminoethyl)amino]propyltrimethoxysilane, 3-[N-(2-aminoethyl)amino]propyltrimethoxysilane, alkoxysilanes having a mercapto group, such as (2-aminoC2-4 alkyl)aminoC2-4 alkyltriC1-4 alkoxysilanes such as (2-aminoC2-4 alkyl)aminoC2-4 alkyltriC1-4 alkoxysilanes, 3-[N-(2-aminoethyl)amino]propylmethyldimethoxysilane, 3-[N-(2-aminoethyl)amino]propylmethyldiethoxysilane, and the like; 2-mercaptoethyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and the like; Alkoxysilanes having a vinyl group, such as trimethoxysilane, mercapto C2-4 alkyltri C1-4 alkoxysilanes such as 3-mercaptopropyltriethoxysilane, mercaptodi C2-4 alkyldi C1-4 alkoxysilanes such as 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, etc.; alkoxysilanes having an ethylenically unsaturated bond group, such as vinyltri C1-4 alkoxysilanes such as vinyltrimethoxysilane, vinyltriethoxysilane, etc.; 2-(meth) Examples include (meth)acryloxyC2-4 alkyltriC1-4 alkoxysilanes such as acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, and 3-(meth)acryloxypropyltriethoxysilane, and (meth)acryloxydiC2-4 alkyldiC1-4 alkoxysilanes such as 3-(meth)acryloxypropylmethyldimethoxysilane and 3-(meth)acryloxypropylmethyldiethoxysilane. These silane coupling agents can be used alone or in combination of two or more.

[0073] Among the above silane coupling agents, a structure represented by (OR)3-Si-X (R is a hydrocarbon group, and X is an epoxy functional group) is preferred. When there are three hydrolyzable silyl groups (-OR), there are many hydrogen bonding sites after hydrolysis, which react with hydroxyl groups (-OH) on the substrate or inorganic layer, resulting in high adhesion.In addition, the structure is strongly bonded by trisiloxy bonds (three (-Si-O-)). Furthermore, when the functional group is an epoxy group, the epoxy group undergoes a ring-opening reaction with the acid terminal (—COOH) of the polyurethane or citric acid, resulting in a strong bismethylenecyclohexane structure.

[0074] The resin layer (B) preferably contains a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt. Although the reaction product of the polyurethane resin, silane coupling agent, and organic salt is found scattered throughout the laminate film due to the thin thickness of the resin layer (B), the reaction product is preferably contained within the resin layer (B). The reaction product is preferably a polymer containing urethane bonds, trisiloxy units, and units derived from bismethylenecyclohexane. Furthermore, the resin layer (B) preferably contains a resin having a silicon compound in which citric acid and an epoxy group have reacted with the polymer skeleton.

[0075] As the crosslinking agent, in addition to a silane coupling agent, an oxazoline compound, a melamine compound, an epoxy compound, a carbodiimide compound, or an isocyanate compound can be used as needed. The crosslinking agents can be used alone or in combination of two or more.

[0076] (organic salts) The resin layer (B) according to the present invention contains a reaction product of the polyurethane resin, a silane coupling agent, and an organic salt. By using the organic salt, the salt concentration in the laminated film can be adjusted to an appropriate range, and in addition to high initial gas barrier properties, the gas barrier properties can be further improved over time. Organic salts are salts in which either the acid or base is derived from an organic compound. Examples of the salt include lithium salts, sodium salts, potassium salts, magnesium salts, calcium salts, and ammonium salts. Examples of organic salts include acidic salts such as sodium bicarbonate, ammonium bicarbonate, and sodium hydrogen sulfate, as well as basic salts such as calcium chloride hydroxide, magnesium chloride hydroxide, and potassium citrate (monopotassium citrate, dipotassium citrate, and tripotassium citrate). Other ammonium salts that may be used include lithium acetate, potassium acetate, potassium propionate, potassium tartrate, potassium lactate, potassium oxalate, potassium maleate, ammonium acetate, tetramethylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide, and choline chloride. Of these, alkali metal salts of organic acids are preferred, potassium salts of organic acids are more preferred, potassium citrate is even more preferred, and salts containing tripotassium citrate monohydrate are even more preferred. In the present invention, the potassium concentration in the laminated film can be adjusted to an appropriate range, and in addition to having high gas barrier properties at the initial stage, the gas barrier properties can be further improved over time. The potassium concentration in the laminated film of the present invention is preferably 0.000005% by mass or more and 5% by mass or less, and more preferably 0.00005% by mass or more and 0.5% by mass or less.

[0077] Here, we will explain the mechanism by which gas barrier properties improve. Specifically, it is presumed that potassium ions in the resin layer (B), along with the water vapor that permeates the laminate film in small amounts, penetrate and fill minute voids or structural defects in the inorganic layer (C), improving the gas barrier properties over time. This is thought to have the same effect as aging the inorganic layer (C) after its formation to make it a dense film. Methods for qualitative and quantitative analysis of potassium in the laminate film or inorganic layer (C) include analyzing the type, amount, and chemical bonding state of the element by X-ray photoelectron spectroscopy (XPS) of the laminate film or inorganic layer (C) as is, or dissolving it in an acid or alkali solution and analyzing the element spectrum by ICP atomic emission spectroscopy.

[0078] The resin layer (B) is formed by applying a coating liquid for forming the resin layer (B) to the base film (A) and drying the coating liquid. When an inorganic layer (C) is provided on the base film (A), the resin layer (B) is formed by applying a coating liquid for forming the resin layer (B) to the inorganic layer (C) and drying the coating liquid. In addition to the polyurethane resin, the silane coupling agent, and the organic salt, various known additives may be blended into the coating liquid as necessary. Examples of such additives include polyhydric alcohols such as glycerin, ethylene glycol, polyethylene glycol, and polypropylene glycol, aqueous epoxy resins, lower alcohols such as methanol, ethanol, propanol, and isopropanol, ethers such as ethylene glycol monomethyl ether, propylene glycol monomethyl ether, propylene glycol diethyl ether, diethylene glycol monoethyl ether, and propylene glycol monoethyl ether, esters such as propylene glycol monoacetate and ethylene glycol monoacetate, antioxidants, weather stabilizers, ultraviolet absorbers, antistatic agents, pigments, dyes, antibacterial agents, lubricants, inorganic fillers, antiblocking agents, adhesives, etc.

[0079] The coating liquid is preferably an aqueous dispersion. Furthermore, the coating liquid can be used in combination with an aqueous dispersion of another resin. Examples of such aqueous dispersions of other resins include one or more aqueous dispersions of polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, water-soluble acrylic resin, acrylamide resin, methacrylamide resin, acrylonitrile resin, styrene-acrylic acid copolymer, water-soluble styrene-maleic acid copolymer, styrene-butadiene copolymer, high-impact polystyrene resin, butadiene resin, polyester resin, acrylonitrile-butadiene copolymer, polyethylene resin, oxidized polyethylene resin, propylene-ethylene copolymer, maleic anhydride-grafted propylene-ethylene copolymer, chlorinated polyethylene, chlorinated polypropylene, ethylene-propylene rubber (EPDM), phenolic resin, silicone resin, and epoxy resin.

[0080] The method for preparing the coating liquid is not particularly limited, but it can be prepared, for example, by adding a silane coupling agent or an aqueous solution thereof to an aqueous dispersion obtained by dissolving or dispersing each resin in water, or by mixing an aqueous dispersion of each resin with a silane coupling agent or an aqueous solution thereof. In the above cases, the coating liquid may be prepared using a solvent other than water, such as an alcohol.

[0081] The coating solution can be applied to the substrate film (A) or the inorganic layer (C) using a known coating method. For example, a coating method using a reverse roll coater, gravure coater, rod coater, air doctor coater, or spray can be used. After coating, moisture can be evaporated using a known drying method such as hot air drying at a temperature of about 80 to 200°C, heat drying such as hot roll drying, or infrared drying. This results in a gas barrier laminate film having a uniform coating layer.

[0082] The thickness of the resin layer (B) is not particularly limited, but is preferably 0.1 to 20 μm, and from the viewpoints of gas barrier properties, cost, etc., it is more preferably 0.1 to 1 μm.

[0083] [Inorganic layer (C)] In the laminated film of the present invention, the inorganic layer (C) inhibits the permeation of water vapor, oxygen gas, etc., and imparts gas barrier properties to the laminated film of the present invention.

[0084] The inorganic layer (C) is preferably a layer containing an inorganic substance, particularly an inorganic oxide, inorganic nitride, or inorganic oxynitride, as a "main material." Here, "main material" means a material that preferably accounts for 50% by mass or more of the inorganic layer (C), more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and preferably 100% by mass or less.

[0085] The inorganic substance as the main material constituting the inorganic layer (C) can include at least one or more inorganic compounds selected from silicon oxide, silicon nitride, silicon oxynitride, silicon oxide carbide, silicon oxycarbonitride, aluminum oxide, aluminum nitride, aluminum oxynitride, and aluminum oxide carbide. Among these, it is preferable to contain, as a main material, one or more inorganic materials selected from the group consisting of silicon oxide, silicon nitride, and aluminum oxide.

[0086] The inorganic layer (C) is preferably, for example, a PVD inorganic layer formed by physical vapor deposition (PVD), a plasma-assisted vapor deposition inorganic layer formed by plasma-assisted physical vapor deposition, a CVD inorganic layer formed by chemical vapor deposition (CVD), or a coated inorganic layer formed by a method in which inorganic particles are dispersed in an organic polymer and applied.

[0087] When the inorganic layer (C) is taken as 100% by mass, the inorganic material preferably accounts for 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

[0088] The inorganic layer (C) may contain alkali metal ions or alkaline earth metal ions to improve the gas barrier properties.

[0089] Furthermore, the inorganic layer (C) may contain an organic substance in addition to the inorganic substance. By mixing an organic substance with an inorganic substance to form an inorganic layer, the inorganic layer can be made relatively flexible. The provision of such a flexible layer can further enhance gas barrier properties. The reason for this is that if there are large protrusions or the like on the surface of the substrate film, these can act as starting points to cause minute defects called pinholes on the surface of the inorganic layer (C), or the raw materials can fly in clumps during thermal evaporation and adhere, causing minute defects on the surface of the inorganic layer (C). Gas can pass through the voids created by these defects, reducing gas barrier properties. In such cases, the provision of a flexible layer can maintain gas barrier properties. Examples of the organic material include polyester resin, acrylic resin, urethane resin, PVA, and organic fillers.

[0090] The inorganic layer (C) may be a single layer or may have a multi-layer structure consisting of two or more layers. For example, an example of a multi-layer structure having two or more layers is one in which one layer is an inorganic layer (C) consisting only of an inorganic substance, such as an inorganic oxide, and the other layer is a layer containing an inorganic oxide and an organic substance. Since the layer containing an inorganic oxide and an organic substance can be made flexible as described above, laminating this layer can fill the defects and improve the gas barrier properties in some cases. Note that the term "flexible layer" encompasses a layer that relieves the stress of the inorganic layer (C) so as to be compatible with applications requiring flexibility, such as flexible applications.

[0091] The thickness of the inorganic layer (C) is preferably 5 nm to 200 nm, more preferably 10 nm to 180 nm, and even more preferably 20 nm to 150 nm, from the viewpoint of ensuring the desired gas barrier properties while maintaining transparency. When there are multiple inorganic layers (C), the thickness refers to the total thickness of the layers. The thickness of the inorganic layer (C) can be measured by preparing an ultrathin cross-sectional slice of the laminated film and observing it with a transmission electron microscope or the like.

[0092] As a method for forming (depositing) the inorganic layer (C), for example, known methods such as physical vapor deposition (PVD) methods such as vacuum heating evaporation method, electron beam method, sputtering method, ion plating method, and chemical vapor deposition (CVD) method can be used. Plasma assist may be combined with the PVD method or the CVD method. When the inorganic layer (C) has a plurality of layers, a plurality of inorganic layer deposition methods may be used.

[0093] In terms of gas barrier properties, the PVD method is preferable. For example, it is preferable to form an inorganic layer made of silicon oxide represented by SiO x (1.0 < x ≦ 2.0). When the value of x in SiO x is small, the gas barrier property is enhanced. When the value of x is large, the colorless transparency is good. From the viewpoint of the balance between the two, 1.5 ≦ x ≦ 2.0 is preferable. SiO x The composition of can be adjusted by the blending composition of the raw materials used, the type of reaction gas, the degree of vacuum, and the deposition rate. The composition of SiO x can be analyzed by X-ray photoelectron spectroscopy (XPS) or the like.

[0094] When combining plasma assist with the PVD method, during vacuum evaporation, it is preferable to evaporate while ionizing the deposited substance by plasma or irradiate gas ions from a separately provided ion source. By plasma assist, oxygen atoms can be efficiently incorporated into the inorganic layer, so that the transparency can be improved without reducing the gas barrier property of the inorganic layer. In addition, since energy can be imparted to the deposited substance by plasma assist, a dense inorganic layer can be formed. In addition, since the excited species in the plasma are highly reactive, oxidation, nitridation, carbonization, etc. of the evaporated substance by introducing gases such as oxygen, nitrogen, and acetylene can be easily controlled. Therefore, in the case of inorganic oxides such as SiO x , AlO x etc., when plasma assist is combined compared to the inorganic layer obtained only by the PVD method, even when the value of x is the same, a dense film structure can be obtained and the gas barrier property can be improved.

[0095] [Other layers] The laminate film of the present invention may have a topcoat layer on the surface of the inorganic layer (C) for the purpose of protecting the inorganic layer (C) and improving its gas barrier properties. Examples of this topcoat agent include resins such as polyvinyl alcohol resins, ethylene vinyl alcohol resins, polyurethane resins, polyester resins, polyolefin resins, acrylic resins, polyvinylidene chloride resins, and polyvinylpyrrolidone resins, as well as ethyleneimine, isocyanate compounds, carbodiimide compounds, epoxy compounds, oxazoline compounds, and alkoxysilanes. These may be used alone or in combination of two or more.

[0096] The thickness of the top coat layer is preferably 0.05 μm or more and 2 μm or less, more preferably 0.1 μm or more and 1.5 μm or less, and even more preferably 0.3 μm or more and 1 μm or less.

[0097] The water vapor permeability of the laminated film of the present invention at a temperature of 40°C and a relative humidity of 90% is preferably 1 g / m 2 ·day or less, preferably 0.95g / m 2 ·day or less, more preferably 0.9 g / m 2 When the laminated film is stored at a temperature of 40°C and a relative humidity of 90%, the ratio ((II) / (I)) of the water vapor permeability (I) after 1 day to the water vapor permeability (II) after 14 days is preferably 0.7 or less, more preferably 0.65 or less, and even more preferably 0.6 or less.

[0098] [Applications of laminated film] (printing) The laminated film of the present invention is suitable for use in food packaging. A specific embodiment includes a laminate in which a printed layer is formed on a coating layer, and a heat-sealable layer or plastic film is further laminated thereon. A water-based or solvent-based resin-containing printing ink can be used to form the printed layer. Examples of resins used in printing inks include acrylic resins, polyurethane resins, polyester resins, vinyl chloride resins, vinyl acetate copolymer resins, and mixtures thereof. Furthermore, known additives such as antistatic agents, light-blocking agents, ultraviolet absorbers, plasticizers, lubricants, fillers, colorants, stabilizers, lubricants, antifoaming agents, crosslinking agents, antiblocking agents, and antioxidants may be added to the printing ink.

[0099] The printing method for providing the printed layer is not particularly limited, and known printing methods such as offset printing, gravure printing, and screen printing can be used. To dry the solvent after printing, known drying methods such as hot air drying, hot roll drying, and infrared drying can be used. It is also possible to laminate at least one layer of paper or plastic film between the printed layer and the heat seal layer or plastic film. As the plastic film, the same thermoplastic resin film as the plastic substrate used in the gas barrier laminate film of the present invention can be used. Among these, paper, polyester resin, polyamide resin, or biodegradable resin is preferred from the viewpoint of obtaining sufficient rigidity and strength of the laminate.

[0100] (heat treatment) In the present invention, after forming the inorganic layer (C), after forming the coating layer, or after laminating a printed layer, a plastic film and / or paper on the coating layer or on the plastic substrate, it is preferable to carry out a heat treatment from the viewpoints of gas barrier properties, stabilization of the film quality of the inorganic layer (C) and the coating layer, etc. This heat treatment may be carried out at any two or more of the above stages. The conditions for the heat treatment vary depending on the type and thickness of the components constituting the gas barrier laminate film or laminate, but are not particularly limited as long as the required temperature and time can be maintained. For example, methods such as storing in an oven or thermostatic chamber set to the required temperature, blowing hot air, heating with an infrared heater, irradiating with light from a lamp, directly applying heat by contacting with a heated roll or hot plate, and irradiating with microwaves can be used. The film may also be cut into easy-to-handle sizes and then heat-treated, or the film may be heat-treated as a roll. Furthermore, as long as the required time and temperature can be obtained, a heating device may be incorporated into a film production device such as a coater or slitter, and heating may be performed during the production process.

[0101] The heat treatment temperature is not particularly limited as long as it is below the melting point of the substrate, plastic film, etc. used. However, a temperature of 60°C or higher is preferred, and 70°C or higher is even more preferred, since this allows for an appropriate treatment time to be set for the heat treatment to be effective. The upper limit of the heat treatment temperature is preferably 200°C, more preferably 160°C, from the viewpoint of preventing a decrease in gas barrier properties due to thermal decomposition of the components constituting the gas barrier laminate film or laminate. The treatment time depends on the heat treatment temperature, and the higher the treatment temperature, the shorter the treatment time is. For example, when the heat treatment temperature is 60°C, the treatment time is approximately 3 days to 6 months; when it is 80°C, the treatment time is approximately 3 hours to 10 days; when it is 120°C, the treatment time is approximately 1 hour to 1 day; and when it is 150°C, the treatment time is approximately 3 to 60 minutes. However, these are merely guidelines, and the treatment times can be adjusted appropriately depending on the type and thickness of the components constituting the gas barrier laminate film or laminate.

[0102] [Laminate film] The laminate film of the present invention is a laminate of a laminated film and a polyolefin resin layer, and can be suitably used for food packaging.

[0103] The water vapor permeability of the laminate film of the present invention at a temperature of 40°C and a relative humidity of 90% is approximately the same as that of the laminate film at a temperature of 40°C and a relative humidity of 90%. Furthermore, when the laminate film is stored at a temperature of 40°C and a relative humidity of 90%, the ratio ((II) / (I)) of the water vapor permeability (I) after 1 day to the water vapor permeability (II) after 14 days is also approximately the same as that of the laminate film. [Example]

[0104] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded.

[0105] [Evaluation method] (1) Water vapor transmission rate (WVTR) The evaluation was carried out in accordance with the conditions of JIS Z0222 "Test method for moisture permeability of moisture-proof packaging containers" and JIS Z0208 "Test method for moisture permeability of moisture-proof packaging materials (cup method)" using the following three procedures. A urethane adhesive (AD900 and CAT-RT85 manufactured by Toyo-Morton Co., Ltd.) mixed in a ratio of AD900:CAT-RT85 = 10:1.5 (mass ratio) was applied to the side of a 60 μm thick unstretched polypropylene (CPP) film (Pylen P1146 manufactured by Toyobo Co., Ltd.) and dried to form an adhesive layer approximately 3 μm thick. The laminated film was dry laminated onto this adhesive layer so that the inorganic layer (B) side of the laminated film was adjacent to the adhesive layer, and dried overnight at 60°C to obtain a laminated film for measuring water vapor permeability. The laminate film was cut into a rectangular shape with a moisture permeability area of ​​10 cm x 10 cm to obtain a test piece. Two test pieces were used, and approximately 20 g of anhydrous calcium chloride was sandwiched between the test pieces as a moisture absorbent, and the four sides were sealed to form a bag. The bag was placed in a thermo-hygrostat at a temperature of 40°C and a relative humidity of 90% RH. The mass was measured (to the nearest 0.1 mg) at intervals of 48 hours or more for up to 14 days, which is the time when the mass increase becomes approximately constant. The water vapor permeability was calculated using the following formula. In the laminate film, the water vapor permeability of the CPP film is significantly greater than that of the laminate film of the present invention, so the contribution of the CPP film to the water vapor permeability is negligible, and the water vapor permeability value of the laminate film in Table 1 can be considered to be the water vapor permeability of the laminate film. The water vapor permeability of the CPP film is 0.02 g / m 2 It is estimated that the level has decreased by about 100%. Water vapor permeability (g / m 2 ·day)=(m / s) / t m: Increase in mass (g) between the last two weighings of the test period s: Moisture permeability area (m 2 ) t: Time (h) between the last two weighings of the test period / 24 (h)

[0106] (2) Calculation of potassium concentration (%) in laminated film The potassium concentration (%) in the laminated film was calculated using the following formula. Potassium concentration in laminated film (%) = [Potassium concentration in resin layer (B) (%) × 3 × resin layer (B) thickness (μm)] / [Thickness of layers other than resin layer (B) (μm)]

[0107] [Explanation of each layer] (1) Base film (A) A biaxially oriented polypropylene film (thickness: 28 μm) was used.

[0108] (2) Resin layer (B) 0.0573 parts of tripotassium citrate monohydrate was dissolved in a mixed solution of 71.9 parts of water and 35.6 parts of isopropanol (IPA). Next, 242.6 parts of Takelac WPB341 (polyurethane resin, solids concentration 30%, manufactured by Mitsui Chemicals, Inc.) and 5.10 parts of KBM-403 (silane coupling agent, epoxy functional group, manufactured by Shin-Etsu Chemical Co., Ltd.) were added in this order and the whole was stirred to prepare a coating solution for forming the resin layer (B).

[0109] (3) Inorganic layer (C) Silica deposition (SiOx) was formed.

[0110] (4) Topcoat layer To a mixed solution of 31.2 parts of water and 37.8 parts of isopropanol (IPA), 156.1 parts of Takelac WPB341 (polyurethane resin, solid content 30%, manufactured by Mitsui Chemicals, Inc.) and 3.30 parts of KBM-403 (silane coupling agent, epoxy functional group, manufactured by Shin-Etsu Chemical Co., Ltd.) were added in that order, and the whole was stirred to prepare a coating liquid for forming a topcoat layer.

[0111] Example 1 An anchor coat (AC) agent for forming a resin layer (B) was applied to a 28 μm-thick biaxially oriented polypropylene (OPP) base film (A) using a gravure roll (300 mesh), and after drying, a resin layer (B) with a thickness of approximately 0.5 μm was formed. Next, silicon oxide (SiO) was vapor-deposited on the resin layer (B) side using a vacuum vapor deposition device by high-frequency heating to form an inorganic layer (C) of SiOx with a thickness of about 35 nm. Next, a coating liquid for forming a top coat (TC) layer was applied to the inorganic layer (C) side using a gravure roll (300 mesh), and after drying, a top coat (TC) layer with a thickness of about 0.5 μm was formed, thereby obtaining a laminated film.

[0112] A urethane adhesive (AD900 and CAT-RT85 manufactured by Toyo-Morton Co., Ltd.) blended in a ratio of AD900:CAT-RT85 = 10:1.5 (mass ratio) was applied to a 60 μm-thick non-oriented polypropylene (CPP) film (Pylen P1146 manufactured by Toyobo Co., Ltd.) and dried to form an adhesive (Ad) layer approximately 3 μm thick. The top coat (TC) layer side of the laminated film was dry-laminated onto the adhesive (Ad) layer of the non-oriented polypropylene (CPP) film, and the resultant film was dried overnight at 60°C to obtain a laminated film.

[0113] Comparative Example 1 A laminated film was obtained in the same manner as in Example 1, except that the anchor coating (AC) agent for forming the resin layer (B) was changed to the following: <Anchor coating agent> To a mixed solution of 71.9 parts of water and 35.6 parts of isopropanol (IPA), 242.6 parts of Takelac WPB341 (polyurethane resin, solids concentration 30%, manufactured by Mitsui Chemicals, Inc.) and 5.10 parts of KBM-403 (silane coupling agent, epoxy functional group, manufactured by Shin-Etsu Chemical Co., Ltd.) were added in that order and stirred to prepare a coating liquid for forming a resin layer. Using the obtained laminated film, a laminate film was obtained by the method described in Example 1. The structure and thickness of each layer of the laminated film, as well as the potassium concentration in the laminated film and the water vapor transmission rate (WVTR) of the laminated film are shown in Table 1 for Example 1 and Comparative Example 1. In Table 1, / indicates the interlayer space of the laminated film, and / / indicates the lamination location.

[0114] [Table 1]

[0115] Comparing the water vapor transmission rates WVTR of Example 1 and Comparative Example 1, it can be seen that the transmission rate on the 14th day (14day, II) of Example 1 is lower than the transmission rate on the 1st day (1day, I) of Example 1, indicating that the gas barrier properties have improved over time. The smaller this ratio ((II) / (I)), the more the gas barrier properties have improved over time. It is believed that this is because the potassium ions in the resin layer (B), along with the small amount of water vapor that permeates the laminated film, penetrate and fill the tiny voids or structural defects in the inorganic layer (C), improving the gas barrier properties over time. [Industrial Applicability]

[0116] The laminate film of the present invention not only has high initial gas barrier properties, but also improves its gas barrier properties over time. In particular, when a polyolefin resin is used as the base film (A) and a polyolefin resin layer is further laminated as a sealant layer to form a laminate film, the laminate film can be suitably used as an environmentally friendly film that is easy to recycle. Therefore, the laminated film of the present invention is suitable as a packaging material for medium- to long-term storage in the food and medical fields, and is an environmentally friendly film that can also be applied to recent environmental issues, and therefore has high industrial value.

Claims

1. A substrate film (A) has a resin layer (B) on at least one surface thereof and an inorganic layer (C) adjacent to the resin layer (B), A laminated film comprising a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt.

2. The laminate film according to claim 1 , wherein the substrate film (A), the resin layer (B), and the inorganic layer (C) adjacent to the resin layer (B) are laminated in this order.

3. The laminate film according to claim 1 , wherein the base film (A), the inorganic layer (C) adjacent to the resin layer (B), and the resin layer (B) are laminated in this order.

4. The laminate film according to claim 1 , wherein the resin layer (B) comprises a reaction product of a polyurethane resin, a silane coupling agent, and an organic salt.

5. 5. The laminate film according to claim 4, wherein the reaction product in the resin layer (B) is a polymer containing a urethane bond, a trisiloxy unit, and a unit derived from bismethylenecyclohexane.

6. Water vapor permeability at a temperature of 40°C and a relative humidity of 90% is 1 g / m 2 The laminated film according to claim 1, wherein the film thickness is 0.5 mm or less.

7. The laminated film according to claim 1 , wherein the base film (A) is a polyolefin-based resin film.

8. The laminated film according to claim 1 , wherein the base film (A) is a polypropylene-based resin film.

9. The laminated film according to claim 1, wherein the base film (A) is a film stretched in at least one direction.

10. 2. The laminate film according to claim 1, wherein the organic salt is an alkali metal salt of an organic acid.

11. 2. The laminate film of claim 1, wherein the organic salt is tripotassium citrate monohydrate.

12. The laminated film according to claim 1 , wherein the resin layer (B) contains a resin having a silicon compound in which citric acid and an epoxy group have reacted with a polymer skeleton.

13. The laminated film according to claim 10, wherein the content of the alkali metal contained in the entire laminated film is 0.00005% by mass or more and 0.5% by mass or less.

14. The laminated film according to claim 1, wherein the resin layer (B) has a thickness of 0.1 μm or more and 20 μm or less.

15. The laminated film according to claim 1, wherein the inorganic layer (C) has a thickness of 5 nm or more and 200 nm or less.

16. The laminate film according to claim 1, wherein the laminate film is stored at a temperature of 40°C and a relative humidity of 90%, and the ratio ((II) / (I)) of the water vapor permeability (I) after 1 day to the water vapor permeability (II) after 14 days is 0.7 or less.

17. The laminated film according to claim 1, which is used for food packaging.

18. A laminate film obtained by laminating the laminate film according to any one of claims 1 to 17 and a polyolefin resin layer.

19. The laminate film according to claim 18, which is used for food packaging.

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