Gas barrier laminate having superior flexibility

Abstract

To provide a gas barrier laminate that enables maintenance of superior gas barrier property under physical stress including bending or elongation, while also having superior transparency.SOLUTION: A gas barrier laminate comprising, on a substrate, at least a gas barrier layer containing an inorganic salt, wherein an organic coating layer is formed on the gas barrier layer.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a gas barrier laminate, and more particularly to a gas barrier laminate that has excellent gas barrier properties as well as excellent flexibility and transparency. [Background technology]

[0002] BACKGROUND ART Gas barrier laminates have been known which are formed by forming a film containing metal atoms and phosphorus atoms as constituent components on a plastic substrate. For example, Patent Document 1 below describes a composite structure having a substrate (X) and a layer (Y) laminated on the substrate (X), wherein the layer (Y) contains a reaction product (R), and the reaction product (R) is a reaction product obtained by reacting at least a metal oxide (A) with a phosphorus compound (B), and the reaction product (R) has a peak density of 800 to 1400 cm -1 The fraction (n) at which the infrared absorption is maximum in the infrared absorption spectrum of the layer (Y) in the range 1 ) is 1080~1130cm -1 and the metal atom (M) constituting the metal oxide (A) is aluminum.

[0003] The composite structure disclosed in Patent Document 1 satisfies both the oxygen barrier property and the water vapor barrier property, but there are concerns about its stability against the acids and alkalis contained in the contents. To solve these problems, the present inventors have proposed a coating composition containing a metal oxide, a phosphoric acid compound, and a polycarboxylic acid salt soluble in the phosphoric acid compound, and a gas barrier laminate having a coating film made of the coating composition (Patent Document 2). In the coating composition for forming a gas barrier coating film according to Patent Document 2, an amine compound containing a polyvalent metal ion and an organic carboxylic acid is used as a specific additive, and the polyvalent metal ion captures the metal ion, and the amine compound reacts with the metal ion, carboxylic acid, and phosphoric acid to be incorporated into a crosslinked structure and function as a binder between metal oxide particles, thereby forming a coating film without defects and enabling the development of superior oxygen barrier properties and water vapor barrier properties.

[0004] However, it has been found that a coating film made of the coating composition of Patent Document 2 may lose its gas barrier properties when formed on a flexible substrate and subjected to bending. Furthermore, as a multilayer structure that maintains its gas barrier properties even when bent, Patent Document 3 listed below proposes a multilayer structure comprising a substrate (X), a layer (Y), and a layer (Z), in which at least one pair of layer (Y) and layer (Z) are laminated adjacent to each other, layer (Y) contains a reaction product (D) of a metal oxide (A) containing aluminum atoms and an inorganic phosphorus compound (BI), layer (Z) contains a vinyl alcohol-based resin (C), the proportion of the vinyl alcohol-based resin (C) in layer (Z) is 90 mass % or more, and layer (Z) has an average thickness of 60 nm or more. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4961054 [Patent Document 2] International Publication No. 2022 / 075352 [Patent Document 3] Patent No. 7339872 Summary of the Invention [Problem to be solved by the invention]

[0006] In the multilayer structure of Patent Document 3, the layer (Z) containing a vinyl alcohol-based resin covers the barrier layer (Y), thereby preventing a decrease in gas barrier properties even when subjected to a bending treatment, but it is desirable to have even higher gas barrier properties. Furthermore, if a layer containing a polyvinyl alcohol-based resin is formed on the gas barrier layer, the laminate may become colored, which may deteriorate the optical properties.

[0007] Therefore, an object of the present invention is to provide a gas barrier laminate that is capable of maintaining excellent gas barrier properties and also has excellent transparency even when subjected to physical stress such as bending or stretching. [Means for solving the problem]

[0008] According to the present invention, there is provided a gas barrier laminate comprising a substrate, a gas barrier layer containing at least an inorganic salt, and an organic coating layer formed on the gas barrier layer.

[0009] In the gas barrier laminate of the present invention, (1) The organic coating layer is at least one selected from a coating film containing a thermosetting resin or a photocurable resin having a glass transition temperature of 70°C or higher, or a thermoplastic resin film having a glass transition temperature of 70°C or higher; (2) The thermosetting resin is an acrylic resin or a bisphenol A type epoxy resin. (3) The acrylic resin contains at least one selected from methyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, and benzotriazole derivative acrylate; (4) The photocurable resin contains an acrylic compound. (5) The thermoplastic resin film is a polyester film. (6) The gas barrier layer is made of a reaction product obtained by reacting at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfuric acid compound; (7) The metal species of the metal alkoxide and metal hydroxide is at least one of aluminum, titanium, iron, and zirconium; (8) The metal alkoxide is at least one of methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide; (9) The metal alkoxide is aluminum isopropoxide. (10) The metal hydroxide is aluminum hydroxide. (11) The metal oxide is zirconium oxide or aluminum oxide. (12) The phosphoric acid compound is at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and cyclic polyphosphoric acid; is preferred. [Effects of the Invention]

[0010] In the gas barrier laminate of the present invention, an organic coating layer is formed on a gas barrier layer formed on a flexible substrate, and therefore even when the gas barrier laminate is subjected to physical stress such as bending or stretching, deterioration of the excellent gas barrier properties (oxygen barrier property and water vapor barrier property) of the gas barrier layer is effectively suppressed. In particular, when a coating film containing a specific curable resin or a specific thermoplastic resin film having a glass transition temperature of 70°C or higher is used as the organic coating layer, an organic coating layer with excellent transparency is formed, and as is clear from the results of the examples described below, it is possible to provide a gas barrier laminate in which the oxygen barrier property and water vapor barrier property are hardly deteriorated before and after the expansion and contraction test. Furthermore, since an organic coating layer made of a crosslinked coating film of a curable resin or a thermoplastic resin film is formed on the gas barrier layer, blocking between overlapping laminates is effectively prevented even when the flexible laminate is wound into a coil, and the laminate also has excellent weather resistance.

[0011] Furthermore, since the gas barrier layer is made of a coating film that contains at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide, together with a metal oxide and a phosphate compound, the gas barrier layer has excellent oxygen barrier properties and water vapor barrier properties due to a uniform and dense crosslinked structure of the metal oxide and the phosphate compound, and is formed as a coating film that is non-yellowing and has excellent transparency.This, combined with the excellent transparency of the organic coating layer described above, means that the organic coating layer fills in any slight irregularities in the gas barrier layer, thereby reducing external haze, and a gas barrier laminate with excellent optical properties can be provided. In other words, metal alkoxides and hydrolysates thereof, and metal hydroxides can supplement metal ions under acidic conditions to eliminate a shortage of metal ions, and also react with the phosphate compound to be incorporated into the crosslinked structure, functioning as a binder between metal oxide particles, allowing the formation of a coating film with fewer defects, which, combined with the uniform and dense crosslinked structure described above, can exhibit better oxygen barrier properties and water vapor barrier properties. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing a cross-sectional structure of an example of the gas barrier laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Organic coating layer) An important feature of the gas barrier laminate of the present invention is that an organic coating layer is formed on a gas barrier layer that is formed on a substrate. This allows the gas barrier layer to conform to the organic coating layer and exhibit flexibility without being damaged, even when subjected to stress due to bending or stretching, as described above, and the gas barrier layer's inherent gas barrier properties are not impaired, allowing it to maintain excellent gas barrier properties. In other words, the organic coating layer is flexible in itself and has excellent adhesion to the gas barrier layer, so that when the laminate is bent or the like, the gas barrier layer can follow the organic coating without being damaged. Such an organic coating layer is preferably at least one selected from a curable coating film containing a thermosetting resin or photocurable resin having a glass transition temperature of 70°C or higher, or a thermoplastic resin film having a glass transition temperature of 70°C or higher.

[0014] [Thermosetting coating film] The thermosetting coating film that can be used as the organic coating layer is a coating film that contains, as a main component, a thermosetting resin with a glass transition temperature of 70°C or higher. The glass transition temperature of 70°C or higher enables the gas barrier laminate to exhibit heat resistance that enables it to withstand use under high-temperature, high-humidity conditions such as those encountered in retort sterilization treatment. The thermosetting resin can be selected from conventionally known thermosetting resins such as acrylic resins, epoxy resins, melamine resins, unsaturated polyester resins, phenolic resins, and urethane resins, as long as it has a glass transition temperature of 70°C or higher. In the present invention, however, acrylic resins or epoxy resins are particularly suitable.

[0015] <Thermosetting acrylic resin> Examples of thermosetting acrylic resins include esters of acrylic acid or methacrylic acid such as methyl (meth)acrylate, isobornyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and n-octyl (meth)acrylate, with methyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, and benzotriazole derivative acrylates being particularly preferred. Note that the above-mentioned (meth)acrylic acid refers to acrylic acid or methacrylic acid. The above (meth)acrylic acid esters can be used alone or in combination, and may also be copolymerized with other monomers. Examples of other comonomers that can be copolymerized with these monomers include, but are not limited to, styrene, vinyl toluene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, vinyl acetate, and benzotriazole derivatives. The acrylic resin that can be suitably used has a hydroxyl value in the range of 5 to 100, preferably 10 to 80, and a number average molecular weight in the range of 500 to 100,000, preferably 1,000 to 50,000.

[0016] As the curing agent for the acrylic resin, an isocyanate-based curing agent can be preferably used, and examples thereof include aliphatic isocyanates such as hexamethylene diisocyanate, pentamethylene diisocyanate, propylene diisocyanate, and butylene diisocyanate, alicyclic isocyanates such as cyclohexane diisocyanate, methylenebis(cyclohexyl isocyanate), and isophorone diisocyanate, aromatic aliphatic isocyanates such as xylylene diisocyanate and tetramethylxylylene diisocyanate, and adducts, dimers, trimers, carbodiimide-modified products, allophanate-modified products, biuret-modified products, and nurate-modified products of these diisocyanates. Among these, aliphatic aromatic isocyanates can be preferably used. The amount of the curing agent cannot be generally defined depending on the type of agent, but it is preferably in the range of 1.0 to 50 parts by mass, particularly 9.0 to 16.4 parts by mass, per 100 parts by mass of the acrylic resin.

[0017] <Epoxy resin> Examples of epoxy resins include glycidyl type epoxy resins such as epoxy resins obtained by glycidylating polyhydric phenols, aliphatic ether type epoxy resins obtained by glycidylating polyhydric alcohols, ether ester type epoxy resins obtained by glycidylating hydroxycarboxylic acids, ester type epoxy resins obtained by glycidylating polycarboxylic acids, and amine type epoxy resins; polyhydric epoxy resins such as alicyclic epoxides; and epoxy compounds such as butyl glycidyl ether, hexyl glycidyl ether, phenyl glycidyl ether, allyl glycidyl ether, 2-ethylhexyl glycidyl ether, p-tert-butylphenyl glycidyl ether, ethylene oxide, propylene oxide, p-xylyl glycidyl ether, glycidyl acetate, glycidyl butyrate, glycidyl hexoate, and glycidyl benzoate. These can be used alone or in combination. In the present invention, bisphenol-type epoxy resins obtained by glycidylating bisphenols can be preferably used, and bisphenol A-type epoxy resins can be preferably used in particular. The epoxy resin that can be suitably used has an epoxy equivalent in the range of 150 to 5000, preferably 170 to 300.

[0018] As the curing agent for the epoxy resin, conventionally known curing agents can be used without any limitation. Examples of such known curing agents include polyfunctional phenols, polyisocyanate compounds, amine compounds, acid anhydride compounds, acid-terminated polyester resins, imidazole compounds, amide compounds, cationic polymerization initiators, and organic phosphines. The amount of the curing agent cannot be generally defined depending on the type of agent, but it is preferably in the range of 1 to 30 parts by mass, particularly 10 to 14.3 parts by mass, per 100 parts by mass of the epoxy resin.

[0019] <Thermosetting resin composition> The thermosetting resin composition can be prepared by adding the above-mentioned thermosetting resin and curing agent to a solvent and mixing them. The solvent may be any solvent conventionally used for acrylic resins or epoxy resins, including, but not limited to, aromatic hydrocarbon solvents such as toluene and xylene; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as ethanol, propanol, and butanol; cellosolve solvents such as ethyl cellosolve and butyl cellosolve; and ester solvents such as ethyl acetate and butyl acetate. One or more of these may be used. Among these, methanol, ethanol, isopropanol, diethyl ether, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, and butyl acetate are preferred.

[0020] [Photocurable resin coating] The photocurable resin coating film that can be used as the organic coating layer in the present invention can be formed from a conventionally known photocurable resin by photoradical polymerization or photocationic polymerization. In the present invention, a photocurable resin composition comprising a photoradical polymerizable acrylic resin and a radical polymerization initiator can be particularly preferably used.

[0021] <Photopolymerizable acrylic resin> Such photoradical polymerizable acrylic resins include those made of mono- or difunctional monomers, polyfunctional monomers, polyfunctional oligomers, or polyfunctional polymers having one or more (meth)acryloyl groups in one molecule. Examples of mono- or difunctional monomers, polyfunctional monomers, polyfunctional oligomers, or polyfunctional polymers include polyester (meth)acrylate, polyurethane (meth)acrylate, epoxy (meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, glycerol tri(meth)acrylate, tris((meth)acryloyloxyethyl)isocyanurate, tris((meth)acryloyloxypropyl)isocyanurate, Pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, tripentaerythritol tetra(meth)acrylate, tripentaerythritol penta(meth)acrylate, tripentaerythritol hexa(meth)acrylate acrylate, tripentaerythritol hepta(meth)acrylate, tripentaerythritol octa(meth); cyclohexyl(meth)acrylate, lauryl(meth)acrylate, stearyl(meth)acrylate, benzyl(meth)acrylate, dicyclopentenyl(meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate, tricyclodecanyl(meth)acrylate, isobornyl(meth)acrylate, isoamyl(meth)acrylate, t-butyl( (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, methoxyethoxyethyl (meth)acrylate, ethoxyethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxypropyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, (meth)acrylic acid, (meth)acryloylmorpholine;Examples include ethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, cyclohexane-1,4-dimethanol di(meth)acrylate, bisphenol A di(meth)acrylate, trimethylolethane di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, trimethylolpropane di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate, neopentyl glycol-modified trimethylolpropane di(meth)acrylate, and bis-(2-(meth)acryloyloxyethyl)phthalate. The molecular weight of the acrylic compound monomer is preferably in the range of 80-1,000, more preferably 100-500.

[0022] The composition may further contain a radically polymerizable compound other than the above-mentioned acrylic compound. Examples of such radically polymerizable compounds include, but are not limited to, polyfunctional radically polymerizable compounds such as aromatic urethane oligomers and aliphatic urethane oligomers having two or more ethylenic double bonds in one molecule, and monofunctional radically polymerizable compounds such as N-vinylformamide, vinylcaprolactam, vinylpyrrolidone, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, allyl glycidyl ether, 1,2-butylene oxide, 1,3-butadiene monoxide, 1,2-epoxydodecane, and epichlorohydrin.

[0023] <Photopolymerization initiator> As the photopolymerization initiator, conventionally known ones can be used, and specific examples thereof include 2,2-diethoxyacetophenone, benzyl dimethyl ketal, benzophenone, methyl o-benzoylbenzoate, bis(4-dimethylaminophenyl)ketone, 1,2-diphenylethanedione, 2-phenyl-2-hydroxyacetophenone, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 4'-isopropyl-2-hydroxy-2-methyl-propiophenone, 2-hydroxy-2-methyl-propiophenone, thioxanthone, 2-methylthioxanthone, and 1-hydroxycyclohexyl phenyl ketone. A photosensitizing aid can also be used together with the photopolymerization initiator. Examples of the photosensitizing aid include tertiary amines such as N,N-dimethyl-p-toluidine, tributylamine, N-methyldiethanolamine, and p-dimethylaminobenzoic acid ethyl ester, as well as anthraquinone, 5-nitrofluorene, and 5-nitroacenaphthene. The photopolymerization initiator is preferably contained in an amount of 1 to 5 parts by mass relative to 100 parts by mass of the acrylic compound.

[0024] <Photocurable resin composition> The photocurable resin composition can be prepared by adding the above-mentioned photocurable resin and photopolymerization initiator to a solvent and mixing them. In the present invention, a mixture of methyl methacrylate and pentaerythritol triacrylate can be particularly suitably used as the photocurable resin composition. As the solvent, the solvents mentioned for the thermosetting resin can be used, but particularly preferred are methanol, ethanol, isopropanol, diethyl ether, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, and the like.

[0025] [Thermoplastic resin film] In the present invention, the thermoplastic resin film having a glass transition temperature of 70°C or higher that can be used as the organic coating layer may be a film made of a conventionally known thermoplastic resin such as polyester, polycarbonate, polyvinyl chloride, polyphenylene sulfide, or polystyrene. In the present invention, however, a film made of polyester is particularly preferred in terms of transparency, heat resistance, mechanical strength, etc. Examples of dicarboxylic acid components constituting the polyester include terephthalic acid, isophthalic acid, orthophthalic acid, p-β-oxyethoxybenzoic acid, naphthalene 2,6-dicarboxylic acid, diphenoxyethane-4,4'-dicarboxylic acid, 5-sodium sulfoisophthalic acid, hexahydroterephthalic acid, adipic acid, sebacic acid, dimer acid, trimellitic acid, and pyromellitic acid. Examples of diol components include ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexylene glycol, pentaerythritol, dipentaerythritol, cyclohexanedimethanol, and ethylene oxide adducts of bisphenol A. These can be appropriately selected so that the glass transition temperature is 70°C or higher. In the present invention, it is particularly preferred that the majority, 80 mol % or more, 95 mol % or more, of the ester repeating units be ethylene terephthalate units, and it is particularly preferred that the ester repeating units be homopolyethylene terephthalate. This polyester resin must have a molecular weight that allows it to be formed into a film, and the number average molecular weight is preferably in the range of 10,000 to 100,000.

[0026] The polyester film can be laminated onto the gas barrier layer by laminating a pre-formed stretched or unstretched film via an adhesive or by thermal bonding, or by laminating an unstretched film directly onto the gas barrier layer by extrusion coating of a molten resin. When a stretched film is used, it can be laminated onto the gas barrier layer via an adhesive or by known means such as thermal bonding.

[0027] (gas barrier layer) In the laminate of the present invention, the configuration of the gas barrier layer is not limited as long as the above-mentioned organic coating layer is formed on the gas barrier layer and the gas barrier layer contains at least an inorganic salt. For example, the gas barrier layer may be made of a conventionally known inorganic vapor deposition layer, but is preferably a gas barrier layer made of a reaction formed product obtained by reacting at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a metal hydroxide, a metal oxide, and a phosphoric acid compound or a sulfuric acid compound. That is, by containing at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide together with a metal oxide and a phosphate compound or a sulfate compound, a uniform and dense cross-linked structure is formed by the metal oxide and the phosphate compound, etc., and by reacting the metal alkoxide, etc. with the phosphate compound, etc., it is incorporated into the cross-linked structure and functions as a binder between the metal oxide particles, thereby enabling the material to exhibit excellent oxygen barrier property and water vapor barrier property.

[0028] Furthermore, the reaction between metal alkoxides and phosphate compounds does not cause yellowing, so a colorless and transparent gas barrier layer can be formed. 2 The coating film formed with this coating amount has a b* value of less than 2.2, especially less than 1.5, in color measurement (CIE 1976 L*a*b* color system), and has reduced yellowness. The coating film that constitutes the gas barrier layer has a wavelength of 800 to 1400 cm by FT-IR measurement of the coating film alone. -1 In the infrared absorption spectrum in the range of 940 to 1120 cm -1 The infrared absorption peak is in the range of 1000 to 10000.

[0029] Furthermore, in the coating film that constitutes the gas barrier layer, the content ratio (P / M) of M (M-kα) of a metal oxide or metal alkoxide, etc., measured by X-ray fluorescence measurement to P (P-kα) of a phosphate compound, etc., measured by X-ray fluorescence measurement, is preferably in the range of 1.30 to 1.82, particularly in the range of 1.36 to 1.82, when zirconium oxide is used as the metal oxide, phosphoric acid as the phosphate compound, etc., and aluminum isopropoxide as the metal alkoxide, etc., and the content ratio (P / Zr) of Zr (Zr-kα) of zirconium oxide, measured by X-ray fluorescence measurement to P (P-kα) of the phosphate compound, etc., measured by X-ray fluorescence measurement, is preferably in the range of 1.30 to 1.82, particularly in the range of 1.36 to 1.82. When the content ratio is within the above range, the phosphate compound reacts efficiently with the hydroxyl groups of the metal oxide in the coating film, neither too much nor too little, making it possible to form a uniform and dense coating film and achieving excellent oxygen barrier properties and water vapor barrier properties. That is, if the content ratio as determined by fluorescent X-ray measurement is less than the above range and there is an insufficient amount of phosphate compound, the bonding between the metal oxide particles will be insufficient and the amount of hydroxyl groups present on the surfaces of the metal oxide particles will increase, which could result in reduced oxygen barrier properties and water vapor barrier properties. On the other hand, if the content ratio as determined by fluorescent X-ray measurement is greater than the above range and there is an excess of phosphate compound, the amount of hydroxyl groups derived from the phosphate groups will increase, which could also result in reduced oxygen barrier properties and water vapor barrier properties.

[0030] Furthermore, when using zirconium oxide as the metal oxide, phosphoric acid as the phosphate compound, etc., and aluminum isopropoxide as the metal alkoxide, etc., it is preferable that the content ratio (Al / Zr) of Zr (Zr-kα) determined by X-ray fluorescence measurement of zirconium oxide to Al (Al-kα) determined by X-ray fluorescence measurement of aluminum isopropoxide is in the range of 0.06 to 0.35, particularly 0.13 to 0.26. When the content ratio is within the above range, it becomes possible to exhibit the above-described effects of the metal alkoxide and the like without impairing the dense cross-linked structure of the zirconium oxide and the phosphate compound, and it becomes possible to exhibit excellent oxygen barrier property and water vapor barrier property.

[0031] [Metal oxides] The metal oxide used in the gas barrier layer is preferably an oxide of a divalent or higher metal atom, and includes, but is not limited to, oxides of magnesium, calcium, iron, zinc, aluminum, silicon, titanium, zirconium, etc., and zirconium oxide is particularly preferred. As used herein, the term "metal oxide" refers to a metal oxide containing, as a main component, a structure represented by MOM, where M represents a metal atom and O represents an oxygen atom. Zirconium oxide contains Zr and O as component elements, and amorphous zirconium oxide contains zirconium hydroxide (Zr(OH)4) and / or zirconyl hydroxide (ZrO(OH)2) as the main component, while crystalline zirconium oxide contains hydrated zirconium oxide (ZrO2·xH2O) and / or zirconium oxide (ZrO2) as the main component. The term "main component" refers to a component that accounts for 50% or more of the total. The crystallinity of zirconium oxide and zirconium oxide that has been applied to a gas barrier coating can be evaluated by identifying the X-ray peaks specific to crystalline zirconium using a conventionally known X-ray structural diffractometer. In the present invention, either crystalline or amorphous zirconium oxide (zirconia) can be used as the zirconium oxide.

[0032] In coating compositions, zirconium oxide is used in the form of a sol in which zirconium oxide particles are used as a dispersoid and an inorganic acid such as nitric acid is blended as a stabilizer. However, in the present invention, in order to prevent the volatilization of the inorganic acid during coating film formation, it is preferable to use a zirconium oxide sol in which a carbonate, ammonium carbonate, an organic dispersant, or the like is used instead of an inorganic acid such as nitric acid. Furthermore, the binder component contains at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a metal hydroxide, which are capable of providing many hydroxyl groups available for reaction with phosphoric acid. Therefore, just as with the use of amorphous zirconium oxide, even when crystalline zirconium oxide is used, it is possible to achieve both oxygen barrier properties and water vapor barrier properties equivalent to those achieved when amorphous zirconium oxide with many hydroxyl groups is used.

[0033] Furthermore, it is desirable that the zirconium oxide particles have an average primary particle size (D50) of 100 nm or less, preferably 50 nm or less, and more preferably 30 nm or less, which allows the formation of a uniform coating film with excellent transparency. The average particle size (D50) is the volume-average particle size measured by laser diffraction / scattering, and D50 is the 50% value in the volume-based particle size distribution. Using such fine particle-type zirconium oxide as a raw material allows the development of excellent transparency.

[0034] [Phosphate compounds] Phosphoric acid compounds used in the present invention include orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, phosphorous acid, phosphonic acid, and their derivatives. Specific examples of polyphosphoric acid include pyrophosphoric acid, triphosphoric acid, and polyphosphoric acid condensed with four or more phosphoric acids. Examples of the above derivatives include salts, (partial) ester compounds, halides (e.g., chlorides), and dehydrates (e.g., diphosphorus pentoxide) of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, phosphorous acid, and phosphonic acid. Examples of phosphonic acid derivatives also include compounds in which the hydrogen atom directly bonded to the phosphorus atom of phosphonic acid (HP(═O)(OH)2) is substituted with an alkyl group that may have various functional groups (e.g., nitrilotris(methylenephosphonic acid), N,N,N′,N′-ethylenediaminetetrakis(methylenephosphonic acid)), as well as salts, (partial) ester compounds, halides, and dehydrates thereof. Furthermore, organic polymers containing phosphorus atoms, such as phosphorylated starch, can also be used. These phosphate compounds can be used alone or in combination of two or more. In the present invention, it is particularly preferable to use at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and cyclic polyphosphoric acid.

[0035] [Sulfuric acid compounds] In the present invention, examples of sulfate compounds that can be used instead of the above-mentioned phosphoric acid compounds to react with metal oxides to form dense coating films include compounds selected from the group consisting of sulfuric acid, sulfates, sulfate esters, alkyl sulfates, polyoxyethylene alkyl ether sulfates, and salts thereof. These sulfate compounds can be used alone or in combination of two or more. In the present invention, sulfuric acid can be particularly preferably used.

[0036] [Metal alkoxide or its hydrolyzate] Metal alkoxides are generally represented by the following formula (1). M n+ (OR)n - ···(1) In the formula, R represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, and n is an integer of 1 or more. Represents.

[0037] In the present invention, it is preferable that the metal atom M in the above formula (1) is any one of aluminum, titanium, iron, and zirconium. In the above formula (1), the organic group R is preferably any one of a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group. In the present invention, as described above, the metal alkoxide is preferably at least one metal alkoxide selected from methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide, and among these, aluminum isopropoxide can be preferably used.

[0038] [Metal hydroxide] Metal hydroxides are generally represented by the following formula (2). M n+ (OH)n - ···(2) In the formula, H represents a hydrogen atom, M represents a metal atom, and n represents an integer of 1 or more. The metal hydroxide is preferably any of the hydroxides of aluminum, titanium, iron, and zirconium listed as examples of metal alkoxides, and among these, aluminum hydroxide is preferably used.

[0039] [Preparation of coating composition for forming gas barrier coating film] In the present invention, the coating composition for forming a gas barrier coating film used to form the gas barrier layer may be either an aqueous or solvent-based composition as long as it contains the above-mentioned metal oxide, phosphate compound, etc. and metal alkoxide, etc., but is preferably an aqueous composition. In the coating composition for forming a gas barrier coating film, it is desirable to use a sol containing metal oxide fine particles as the dispersoid as the metal oxide. Furthermore, it is preferable to use a sol containing metal oxide fine particles as the dispersoid that does not contain a volatile acid as a stabilizer, in order to prevent the adverse effects of acid generation on equipment and the working environment. For the above reasons, it is desirable not to use, as a deflocculating agent, volatile acids such as nitric acid, hydrochloric acid, and acetic acid, which have been used to prepare dispersions with excellent transparency and viscosity stability.

[0040] The coating composition for forming a gas barrier coating film is prepared by mixing a metal oxide, a phosphoric acid compound, etc., and a metal alkoxide, etc. in a solvent capable of dissolving the phosphoric acid compound, etc. and the metal alkoxide, etc. As such an aqueous medium, conventionally known aqueous solvents such as distilled water, ion-exchanged water, and pure water can be used. Similar to known aqueous compositions, organic solvents such as alcohols, polyhydric alcohols, their derivatives, and ketones can be contained. When such a cosolvent is used, it can be contained in an amount of 1 to 90 wt % of the aqueous solvent in the aqueous composition. By including a solvent in the above range, film-forming performance is improved. Preferred organic solvents are those having amphiphilic properties, such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, sec-butyl alcohol, tert-butyl alcohol, butyl cellosolve, propylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, 3-methyl-3-methoxybutanol, acetone, and methyl ethyl ketone.

[0041]

[0033] In addition, commonly known dispersion treatments can be used to prepare the coating composition for forming a gas barrier coating film. Known dispersion treatment methods include pulverization of fine particles by cavitation using an ultrasonic homogenizer, mechanical dispersion treatment using a disperser with rotating blades, and dispersion using a mill with glass or zirconia beads. These fine dispersion treatments for coatings can be suitably used in the present invention.

[0042] In the coating composition for forming a gas barrier coating film, a phosphate compound or the like and a metal alkoxide or the like can be added to the metal oxide within a range that does not impair the oxygen barrier property and water vapor barrier property. The amount of the phosphate compound or the like to be added varies depending on the type of phosphate compound or the like used and cannot be generally specified. However, when zirconium oxide is used as the metal oxide, phosphoric acid as the phosphate compound or the like, and aluminum isopropoxide as the metal alkoxide or the like, it is preferable to blend in an amount of 53 to 86 parts by mass, and particularly 53 to 64 parts by mass, of the nonvolatile content of phosphoric acid per 100 parts by mass of the solid content of zirconium oxide.

[0043] The amount of metal alkoxide or the like to be added varies depending on the type of metal alkoxide or the like used and cannot be generally defined. However, when zirconium oxide is used as the metal oxide, phosphoric acid is used as the phosphate compound or the like, and aluminum isopropoxide is used as the metal alkoxide or the like, it is preferable to add aluminum isopropoxide in an amount of 45 to 49 parts by mass per 100 parts by mass of the solid content of zirconium oxide. If the amount added is less than the above range, the effect obtained by adding a metal alkoxide or the like will not be as sufficient as when it is within the above range, and if the amount added is greater than the above range, not only will no further effect be obtained, but there is also a risk of defects in the barrier structure of the coating film as compared to when it is within the above range.

[0044] Furthermore, it is preferable that the coating composition for forming a gas barrier coating film contains a catalyst capable of promoting the reaction between the metal oxide or metal alkoxide used and the phosphoric acid compound, etc. This promotes the crosslinking reaction of the coating composition, making it possible to reduce the heating temperature and heating time for forming the coating film. Examples of such catalysts include acid catalysts such as paratoluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and cumenesulfonic acid, as well as amine neutralization products of these acids. Of these, paratoluenesulfonic acid is particularly preferred. The acid catalyst is preferably contained in an amount of 0.1 to 10 parts by mass, particularly 1 to 3 parts by mass, per 100 parts by mass of the solid content of zirconium oxide. In addition to the above components, the coating composition for forming a gas barrier coating film may also contain a crosslinking agent, a metal complex, a condensation accelerator, a polymer compound, a filler, a plasticizer, an antioxidant, an ultraviolet absorber, a flame retardant, an antifoaming agent, a colorant, etc.

[0045] (Gas barrier laminate) The gas barrier laminate of the present invention is a laminate comprising a gas barrier layer made of the gas barrier coating film described above and an organic coating layer formed on the gas barrier layer on at least one surface of a substrate, and preferably comprises a gas barrier layer 3 and an organic coating layer 4 formed in this order on a substrate 1 via an anchor coat layer 2 described below, as shown in Figure 1. The anchor coat layer 2 is a coating film that has excellent adhesion to the plastic substrate 1, and by forming the gas barrier layer on this coating film, the interlayer adhesion between the gas barrier layer and the plastic substrate is significantly improved, and peeling of the gas barrier layer from the substrate can be effectively prevented even when subjected to retort sterilization.

[0046] The gas barrier laminate of the present invention has a gas barrier layer itself that has sufficient gas barrier properties, particularly oxygen barrier properties and water vapor barrier properties, and is made of a 25 μm-thick biaxially oriented polyester substrate film, a coating amount of 2.0 g / m 2 The gas barrier coating film (gas barrier layer) has a coating amount of 2.0 g / m 2 In the case where the material is provided with an organic coating layer made of a thermosetting resin or a photocurable resin, or an organic coating layer made of a polyester film with a thickness of 25 μm, the oxygen permeability (based on JIS K-7126) is 1 cc / m or less before and after the bending test. 2 ·day·atm (40℃ 90%RH) or less, and the water vapor permeability is 1g / m 2 It has excellent oxygen and water vapor barrier properties, with a maximum permeability of less than 1000 times that of conventional polyethylene terephthalate (PEPE) at temperatures of 40°C and 90% RH, and also has excellent flexibility. Furthermore, the gas barrier laminate in which an organic coating layer is formed on the above-mentioned base film and gas barrier layer has excellent transparency with a total light transmittance of 88% or more and a haze of 6.5% or less, and also has a b value of 1.0 or less, thereby suppressing yellowing.

[0047] [Base material] The substrate for the gas barrier laminate may be a conventionally known substrate made of a resin such as a thermoplastic resin or a thermosetting resin, or a fiber such as paper or nonwoven fabric, but preferred examples include any packaging material in the form of a film, sheet, bottle, cup, tray, can, or the like, produced from a thermoformable thermoplastic resin by means of extrusion molding, biaxially oriented film molding, cast film molding, injection molding, blow molding, stretch blow molding, press molding, or the like.

[0048] Examples of thermoplastic resins that can be used for the substrate include olefin copolymers such as low-, medium-, or high-density polyethylene, linear low-density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-1-butene copolymer, ionomer, ethylene-vinyl acetate copolymer, and ethylene-vinyl alcohol copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, and polyethylene naphthalate; polyamides such as nylon 6, nylon 6,6, nylon 6,10, and metaxylylene adipamide; styrene copolymers such as polystyrene, styrene-butadiene block copolymer, styrene-acrylonitrile copolymer, and styrene-butadiene-acrylonitrile copolymer (ABS resin); vinyl chloride copolymers such as polyvinyl chloride and vinyl chloride-vinyl acetate copolymer; acrylic copolymers such as polymethyl methacrylate and methyl methacrylate-ethyl acrylate copolymer; and polycarbonate. In addition, in view of recent environmental concerns, chemically recycled polyethylene terephthalate, mechanically recycled polyethylene terephthalate, biomass-derived polyethylene terephthalate, biomass-derived olefin, recycled olefin, etc. can be used. In the present invention, a sheet made of polyethylene terephthalate, polybutylene terephthalate or polypropylene can be particularly suitably used.

[0049] These thermoplastic resins may be used alone or in the form of a blend of two or more kinds, or different resins may be present in the form of a laminate. The plastic substrate may have a single layer structure or a laminate structure of two or more layers formed by, for example, simultaneous melt extrusion or other lamination. If desired, one or more additives such as pigments, antioxidants, antistatic agents, UV absorbers, and lubricants may be added to the melt-moldable thermoplastic resin in a total amount of 0.001 to 5.0 parts by mass per 100 parts by mass of the resin.

[0050] Furthermore, for example, in order to reinforce this container, one or more of the following fiber reinforcing materials may be blended in a total amount of 2 to 150 parts by mass per 100 parts by mass of the thermoplastic resin: glass fiber, aromatic polyamide fiber, carbon fiber, pulp, cotton linter, etc.; powder reinforcing materials: carbon black, white carbon, etc.; or flake-like reinforcing materials: glass flakes, aluminum flakes, etc.; and for the purpose of further increasing the weight, one or more of the following materials may be blended in a total amount of 5 to 100 parts by mass per 100 parts by mass of the thermoplastic resin according to a formulation known per se. Furthermore, for the purpose of improving gas barrier properties, scaly inorganic fine powders such as water-swellable mica, clay, etc. may be blended in a total amount of 5 to 100 parts by mass per 100 parts by mass of the thermoplastic resin according to a known formulation. Similarly, for the purpose of improving the gas barrier properties, there is no problem in providing a thin film layer of an inorganic material such as silicon oxide or aluminum oxide on a plastic substrate by physical or chemical vapor deposition.

[0051] The substrate may be a final film, sheet, or molded article such as a container, or the like, or the coating may be provided in advance on a preform for molding into a container. Examples of such preforms include cylindrical parisons with or without bottoms for biaxially stretched blow molding, pipes for molding plastic containers, sheets for vacuum forming, pressure forming, and plug-assist molding, or films for heat-sealed lids and bags.

[0052] [Anchor coat layer] As the anchor coat layer to be formed on the surface of the substrate as required, those used in gas barrier laminates can be used, and anchor coat layers made of conventionally known polyurethane resins that are made by combining a hydroxyl group-containing compound as a main component such as an acrylic resin or polyol with an isocyanate-based curing agent, or anchor coat layers further containing a silane coupling agent, or anchor coat layers made of a hydrophilic group-containing resin and a silane coupling agent can be suitably used.

[0053] <Polyurethane resin> As the polyurethane resin constituting the anchor coat layer, a polyurethane resin composed of a hydroxyl group-containing compound as a main component, such as a known acrylic resin or polyol, which has been conventionally used as an anchor coat layer, and an isocyanate compound can be used. In the present invention, it is desirable to use a polyurethane resin having a glass transition temperature (Tg) of 80° C. or higher, particularly in the range of 80 to 120° C. If the glass transition temperature is lower than the above range, the heat resistance of the anchor coat layer will be inferior compared to when the glass transition temperature is within the above range, and when the gas barrier layer is dried, cracks may occur in the gas barrier layer when the gas barrier coating film shrinks due to heating, resulting in a decrease in barrier properties.

[0054] As the acrylic resin, polymers and copolymers synthesized by solution polymerization or suspension polymerization using a conventionally known radical initiator or the like can be used. The glass transition temperature of the acrylic resin is preferably −50 to 100° C., more preferably 40 to 100° C. The number average molecular weight of the acrylic resin is preferably 500,000 to 100,000, more preferably 500,000 to 80,000 The hydroxyl value of the acrylic resin is preferably 10 to 200 mgKOH / g, more preferably 80 to 180 mgKOH / g. The monomer for forming the copolymer is not particularly limited, but copolymers of methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-hydroxyethyl methacrylate, tert-butyl acrylate, etc., combined as necessary, can be used. Examples of polyols include glycols, polyester polyols, polyether polyols, acrylic polyols, and urethane-modified versions of these, with acrylic polyols and glycols being particularly preferred.

[0055] The glass transition temperature of the polyester polyol is preferably −50 to 100° C., more preferably −20 to 80° C. The number average molecular weight of these polyester polyols is preferably 500,000 to 100,000, more preferably 500,000 to 80,000. Examples of glycols include ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neopentyl glycol, and 1,6-hexanediol.

[0056] As the isocyanate component which is a curing agent for polyurethane resins, aromatic diisocyanates, araliphatic diisocyanates, alicyclic diisocyanates, aliphatic diisocyanates, etc. can be used. Examples of aromatic diisocyanates include tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof), 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate or a mixture thereof) (MDI), 4,4'-toluidine diisocyanate (TODI), and 4,4'-diphenyl ether diisocyanate. Examples of aromatic aliphatic diisocyanates include xylene diisocyanate (1,3- or 1,4-xylene diisocyanate or a mixture thereof) (XDI), tetramethyl xylene diisocyanate (1,3- or 1,4-tetramethyl xylene diisocyanate or a mixture thereof) (TMXDI), and ω,ω'-diisocyanato-1,4-diethylbenzene.

[0057] Examples of alicyclic diisocyanates include 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorodiisocyanate, IPDI), methylene bis(cyclohexyl isocyanate) (4,4'-, 2,4'-, or 2,2'-methylene bis(cyclohexyl isocyanate)) (hydrogenated MDI), methyl cyclohexane diisocyanate (methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate), bis(isocyanatomethyl)cyclohexane (1,3- or 1,4-bis(isocyanatomethyl)cyclohexane or a mixture thereof) (hydrogenated XDI), and the like.

[0058] Examples of aliphatic diisocyanates include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), hexamethylene diisocyanate, pentamethylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caffeate.

[0059] The polyisocyanate component may be a polyfunctional polyisocyanate compound such as isocyanurate, biuret, or allophanate derived from the above polyisocyanate monomer, or a polyfunctional polyisocyanate compound having a terminal isocyanate group obtained by reaction with a trifunctional or higher polyol compound such as trimethylolpropane or glycerin. The polyisocyanate component preferably has a glass transition temperature (Tg) of 50° C. or higher and a number average molecular weight (Mn) of 400 or higher, and more preferably has a glass transition temperature (Tg) of 60° C. or higher and a number average molecular weight (Mn) of 500 or higher. In the present invention, it is preferable to use xylene diisocyanate among the above isocyanate components.

[0060] <Hydrophilic group-containing resin> Examples of hydrophilic group-containing resins include, but are not limited to, water-dispersible or water-soluble polyester resins, water-dispersible or water-soluble acrylic resins, and water-dispersible or water-soluble polyurethane resins. In the present invention, polyester resins are preferred, and carboxyl group-containing polyester resins are particularly preferred.

[0061] The carboxyl group-containing polyester resin can be prepared by combining a carboxylic acid anhydride such as phthalic anhydride, succinic anhydride, maleic anhydride, trimellitic anhydride, itaconic anhydride, or citraconic anhydride with a monomer component typically used in the polymerization of polyester resins. Examples of such monomer components include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalenedicarboxylic acid; aliphatic dicarboxylic acids such as succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and dimer acid; unsaturated dicarboxylic acids such as maleic acid (anhydride), fumaric acid, and terpene-maleic acid adducts; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid, tetrahydrophthalic acid, hexahydroisophthalic acid, and 1,2-cyclohexenedicarboxylic acid; and trivalent or higher polycarboxylic acids such as trimellitic acid (anhydride), pyromellitic acid (anhydride), and methylcyclohexene tricarboxylic acid. One or more of these may be selected and used. In the present invention, from the viewpoint of heat resistance, etc., it is preferable that the proportion of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and naphthalenedicarboxylic acid in the polycarboxylic acid components constituting the polyester resin is 50 mol% or more.

[0062] The polyhydric alcohol component constituting the polyester resin is not particularly limited, and examples thereof include ethylene glycol, propylene glycol (1,2-propanediol), 1,3-propanediol, 1,4-butanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl-2-butyl-1,3-propanediol, 2,4-diethyl-1,5-pentanediol, 1-methyl-1,8-octanediol, 3-methyl-1,6-hexanediol, 4-methyl-1,7-heptanediol, 4-methyl The polyhydric alcohol component may be selected from aliphatic glycols such as 4-propyl-1,8-octanediol, 4-propyl-1,8-octanediol, and 1,9-nonanediol; ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; alicyclic polyalcohols such as 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, tricyclodecane glycols, and hydrated bisphenols; and trihydric or higher polyalcohols such as trimethylolpropane, trimethylolethane, and pentaerythritol. Among the above polyhydric alcohol components, ethylene glycol, propylene glycol, and neopentyl glycol are preferably used in the present invention.

[0063] The carboxyl group-containing polyester resin can be produced by known methods, such as polycondensing one or more of the above-mentioned polycarboxylic acid components with one or more of the polyhydric alcohol components, depolymerizing the resulting mixture after polycondensation with a polycarboxylic acid component such as terephthalic acid, isophthalic acid, trimellitic anhydride, trimellitic acid, or pyromellitic acid, or ring-opening and adding an acid anhydride such as phthalic anhydride, maleic anhydride, trimellitic anhydride, or ethylene glycol bistrimellitate dianhydride after polycondensation.

[0064] The carboxyl group-containing polyester resin preferably has an acid value of 1 to 80 KOHmg / g, particularly 10 to 30 KOHmg / g, and a glass transition temperature (Tg) of 0 to 120°C, particularly 67 to 80°C. The carboxyl group-containing polyester resin used may be a blended polyester resin, as long as the acid value and Tg after blending fall within the above ranges. The carboxyl group-containing polyester resin is preferably an amorphous polyester.

[0065] <Silane coupling agent> As the silane coupling agent used in the anchor coat layer, an epoxy-based silane coupling agent can be suitably used. Examples of such epoxy-based silane coupling agents that can be used include β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and 3-glycidoxypropyltrimethoxysilane. Other silane coupling agents include tetramethoxysilane, tetraethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and 3-isocyanatepropyltriethoxysilane, and can be used as needed. Furthermore, for the purpose of improving hot water resistance adhesion, the silane coupling agent used may be hydrolyzed as necessary to promote a condensation reaction of the silane coupling agent.

[0066] [Anchor coat layer forming composition] In the present invention, the composition for forming the anchor coat layer may be either water-based or solvent-based, but from the viewpoint of the working environment, it is preferable to use an aqueous composition. When the above-mentioned polyurethane resin is used in the composition for forming the anchor coat layer, it is preferable that the composition further contains an epoxy-based silane coupling agent. In addition, the polyurethane resin used is preferably a water-soluble or water-dispersible polyurethane. On the other hand, when the above-mentioned hydrophilic group-containing resin is used in the composition for forming the anchor coat layer, it is desirable that the composition be prepared by containing, among others, a carboxyl group-containing polyester resin and an epoxy-based silane coupling agent. The epoxy-based silane coupling agent is preferably contained in an amount of 1 to 80 parts by mass per 100 parts by mass of the solid content of the polyurethane-based resin, while it is preferably blended in an amount of 100 to 400 parts by mass, particularly 150 to 300 parts by mass, per 100 parts by mass of the solid content of the carboxyl group-containing polyester resin. If the amount of epoxy silane coupling agent is less than the above range, the crack resistance when dried cannot be obtained satisfactorily compared with the case where the amount is within the above range. On the other hand, if the amount of epoxy silane coupling agent is more than the above range, it is difficult to further improve the adhesion and crack resistance, and there is a risk that the hot water resistance will be impaired, and furthermore, it will be inferior from the viewpoint of economic efficiency.

[0067] The aqueous medium may contain the same conventionally known aqueous medium as that used in the gas barrier layer-forming composition, as well as organic solvents such as alcohols, polyhydric alcohols, and derivatives thereof. In addition to the above components, the anchor coat layer-forming composition may also contain known curing-accelerating catalysts, fillers, softeners, antioxidants, stabilizers, adhesion promoters, leveling agents, antifoaming agents, plasticizers, inorganic fillers, tackifying resins, fibers, colorants such as pigments, pot life extenders, etc.

[0068] (Method of manufacturing gas barrier laminate) In the method for producing a gas barrier laminate of the present invention, the coating composition for forming a gas barrier coating film can be applied directly to at least one surface of the above-mentioned substrate, but it is preferable to apply the above-mentioned composition for forming an anchor coat layer prior to applying the coating composition for forming a gas barrier coating film. The coating amount of the anchor coat layer-forming composition is determined by the content of the polyurethane resin or carboxyl group-containing polyester resin and the silane coupling agent in the composition, and cannot be generally determined, but is generally in the range of 0.05 to 1.00 g / m2 in terms of the solid weight of the coating film. 2 , especially 0.10 to 0.50 g / m 2 If the anchor coat coating weight is less than the above range, the anchor coat layer may not be able to be fixed to the substrate as well as when it is within the above range, while if the anchor coat coating weight is more than the above range, it becomes less economical. The anchor coat layer-forming composition applied to the substrate is dried at a temperature of 80 to 150°C for 1 to 60 seconds to remove the solvent from the composition, depending on the composition and coating amount used. This allows the anchor coat layer to be formed economically without affecting the substrate, even if it is made of a plastic with a low melting point, such as polypropylene.

[0069] Next, the coating composition for forming a gas barrier coating film is applied onto the composition for forming an anchor coat layer, which has been dried after the solvent has been removed. The coating amount of the coating composition for forming a gas barrier coating film is determined by the contents of metal oxides, phosphate compounds, metal alkoxides, etc. in the composition and cannot be generally defined, but is generally 0.05 to 3.0 g / m2 in terms of the solid weight of the coating film. 2 , especially 0.1 to 2.0 g / m 2 It is preferable to coat the film so that the coating amount falls within the above range. If the coating amount is less than the above range, sufficient barrier properties cannot be obtained. On the other hand, if the coating amount is more than the above range, it is only inferior in economic efficiency and does not offer any particular advantage.

[0070] Next, an organic coating layer is formed. When forming an organic coating layer made of a thermosetting resin as the organic coating layer, the aforementioned thermosetting resin composition is applied onto the coating composition for forming a gas barrier coating film, which has been dried to remove the solvent by drying at a temperature of 80 to 150°C for 1 to 60 seconds. This reduces the difference in heat-induced shrinkage between the gas barrier layer and the organic coating layer, and between the gas barrier layer and the anchor coat layer formed as needed, making it possible to improve the crack resistance of the gas barrier layer, and also significantly improves the interlayer adhesion between the gas barrier layer and the organic coating layer, and between the gas barrier layer and the anchor coat layer formed as needed, and effectively prevents the gas barrier layer from peeling off from the substrate or the organic coating layer from the gas barrier layer, even when subjected to retort sterilization.

[0071] The coating amount of the thermosetting resin composition is determined by the type and content of the thermosetting resin and curing agent, and cannot be generally defined, but is generally in the range of 2.0 to 11 g / m2 in terms of the solid weight of the coating film. 2 , especially 2.0 to 8.3 g / m 2 It is preferable to coat the film so that the coating weight falls within the above range. If the coating weight is less than the above range, the gas barrier layer cannot be protected as sufficiently as when the coating weight is within the above range, and the gas barrier properties may be reduced due to bending, etc. On the other hand, if the coating weight is greater than the above range, it is only less economical and does not offer any particular advantage. The thermosetting resin composition is applied onto the dry coating composition for forming a gas barrier coating film, and then dried for 1 to 2 minutes at a temperature of 60 to 130°C to volatilize and remove the solvent from the thermosetting resin composition. Next, although this cannot be generally determined depending on the composition and coating amount of the metal oxide, phosphate compound, etc., and metal alkoxide, etc., in the coating composition for forming a gas barrier coating film, as well as the types of thermosetting resin, curing agent, solvent, etc., the composition is cured at a temperature of 50°C for 3 to 5 days to crosslink and harden the composition, forming an organic coating layer.

[0072] When a photocurable resin is used for the organic coating layer, the gas barrier layer is formed by heating the coating composition for forming a gas barrier coating film and the anchor coat layer at a temperature of 80 to 220°C, preferably 140 to 220°C, for 1 second to 10 minutes before applying the photocurable resin composition, and then applying the photocurable resin composition onto the formed gas barrier layer. The coating amount of the photocurable resin composition is determined by the type and content of the photocurable resin and polymerization initiator, and cannot be generally defined, but is generally in the range of 2.0 to 11 g / m2 in terms of the solid weight of the coating film. 2 , especially 2.0 to 2.4 g / m 2 It is preferable to coat the film so that the coating weight falls within the above range. If the coating weight is less than the above range, the gas barrier layer cannot be protected as sufficiently as when the coating weight is within the above range, and the gas barrier properties may be reduced due to bending, etc. On the other hand, if the coating weight is greater than the above range, it is only less economical and does not offer any particular advantage. After applying the photocurable resin composition onto the coating composition for forming a gas barrier coating film in a dry state, the composition is dried at a temperature of 60 to 130°C for 1 to 2 minutes to volatilize and remove the solvent of the photocurable resin composition. After that, the exposure time cannot be generally specified depending on the type of photocurable resin, photopolymerization initiator, solvent, or light source, but is generally 600 to 700 J / cm 2 It is preferable to irradiate in the range of The light source for ultraviolet irradiation is not limited to, but may be a conventionally known one such as a chemical lamp, a xenon lamp, a low-pressure mercury lamp, a high-pressure mercury lamp, or a metal halide lamp.

[0073] The application of the anchor coat layer forming composition, the gas barrier coating film forming coating composition, the thermosetting resin composition or the photocurable resin composition, and the drying or heat treatment can be carried out by a conventionally known method. The application method is not limited to these, but for example, spray coating, immersion, or application with a bar coater, roll coater, gravure coater, or the like is possible. The drying or heating treatment can be carried out by oven drying (heating), infrared heating, high frequency heating, vacuum drying, superheated steam, or the like.

[0074] Furthermore, when a film made of a thermoplastic resin having a glass transition temperature of 70°C or higher is used as the organic coating layer, a gas barrier layer can be formed, and then an organic coating layer made of a thermoplastic resin film can be formed on the gas barrier layer by a known method, in the same manner as when a photocurable resin composition is used. The thickness of the thermoplastic resin film is preferably in the range of 12 to 100 μm, particularly 25 to 50 μm. If the thickness is thinner than the above range, it is difficult to impart sufficient flexibility to the laminate compared to when the thickness is within the above range, while if the thickness is thicker than the above range, flexibility may be impaired. When the adhesion between the thermoplastic resin film and the gas barrier layer is poor, the thermoplastic resin film can be laminated on the gas barrier layer via an adhesive layer. As the adhesive, a conventionally known adhesive such as a urethane adhesive or an epoxy adhesive can be used. [Example]

[0075] The present invention will be further explained by the following examples, but the present invention is not limited to these examples. Various measurement and evaluation methods in the examples and comparative examples are as follows.

[0076] Example 1 [Preparation of composition for organic coating layer and coating composition for forming gas barrier coating film] A thermosetting acrylic resin (A) (a copolymer of benzotriazole derivative acrylate, methyl methacrylate, and 2-hydroxyethyl methacrylate, solids content = 40%) was used as a composition for an organic coating layer (hereinafter referred to as "overcoat paint") and diluted with ethyl acetate. Next, an isocyanate-based curing agent (A) (a trimethylolpropane adduct of xylene diisocyanate, solids content = 75%) was added as a curing agent in an amount of 16.4 parts by mass per 100 parts by mass of the solids content of the thermosetting acrylic resin, and the mixture was stirred for a predetermined time to produce an overcoat paint. Next, a gas barrier coating film-forming coating composition (hereinafter referred to as "barrier coat coating") was prepared using zirconium oxide sol (Zirconia sol ZSL-00120B (crystalline zirconium oxide, tetragonal system, solid content (ZrO2 equivalent) = 20%) manufactured by Daiichi Kigenso Kagaku Kogyo Co., Ltd.) as the metal oxide. First, the zirconium oxide sol was prepared using water and isopropanol solvent so that the solid content was 6.1% and the water / isopropanol ratio was 60 / 40. Next, 44.7 parts by mass of aluminum isopropoxide (manufactured by Wako Pure Chemical Industries Co., Ltd.) as an additive and 53.5 parts by mass of phosphoric acid (manufactured by Wako Pure Chemical Industries Co., Ltd., concentration = 75%) as a phosphate compound were added to the mixture, based on 100 parts by mass of the solid content of the zirconium oxide sol, and the mixture was stirred for a predetermined time to obtain a barrier coat coating.

[0077] [Method for producing gas barrier laminate] A gas barrier laminate was produced using the prepared barrier coating paint and overcoat coating paint as follows: The above-mentioned barrier coating paint was applied to a substrate of 25 μm thick biaxially oriented polyester film (E5102 manufactured by Toyobo Co., Ltd.) using a bar coater in an amount of 2.0 g / m 2 The coating was then heated and dried in a box oven at 200°C for 2 minutes. After that, the same overcoat coating was applied using a bar coater to a coating amount of 2.03 g / m 2 The coating was then dried by heating in a box oven at 100°C for 10 minutes and cured at 50°C for 3 days to obtain a sample of a gas barrier laminate.

[0078] Example 2 For the overcoat paint, a photocurable resin (a mixture of acrylic acrylate, pentaerythritol triacrylate, isobornyl methacrylate, and methyl methacrylate, solid content = 66%) was used and diluted with methyl ethyl ketone. Next, Irgacure 184 was added as a photopolymerization initiator so that the amount was 3 parts by mass per 100 parts by mass of the photocurable resin, and the mixture was stirred for a predetermined time to produce the overcoat paint. The overcoat paint was applied using a bar coater at a coating amount of 2.40 g / m.2 The coating was applied so that the coating was uniform, and the coating was dried by heating in a box oven at 60°C for 1 minute, followed by irradiating with a high-pressure mercury lamp at 630 J / cm 2 A sample of the gas barrier laminate was obtained in the same manner as in Example 1, except that the light intensity was irradiated.

[0079] Example 3 As the overcoat paint, a thermosetting epoxy resin (epoxy bisphenol A resin, solid content = 33%) was used, and an isocyanate-based curing agent (B) (hexamethylene-1,6-diisocyanate homopolymer, solid content = 48%) was added as a curing agent in an amount of 14.3 parts by mass per 100 parts by mass of the solid content of the thermosetting epoxy resin, and the mixture was stirred for a predetermined time to form the overcoat paint. The overcoat paint was applied using a bar coater at a coating amount of 5.84 g / m. 2 The coating was then heated and dried in a box oven at 130°C for 1 minute and cured at 50°C for 5 days, in the same manner as in Example 1, to obtain a gas barrier laminate sample.

[0080] Example 4 For the overcoat paint, a thermosetting acrylic resin (B) (acrylic polyol, methyl methacrylate-isobornyl methacrylate (2-hydroxyethyl methacrylate) copolymer, solid content = 50%) was used and diluted with methyl ethyl ketone. Then, an isocyanate-based curing agent (A) (trimethylolpropane adduct of xylene diisocyanate, solid content = 75%) was added as a curing agent so that the amount was 9.4 parts by mass per 100 parts by mass of the solid content of the thermosetting acrylic resin, and the mixture was stirred for a predetermined time to prepare the overcoat paint. The above-mentioned overcoat paint was applied using a bar coater at a coating amount of 3.44 g / m 2 The coating was then heated and dried in a box oven at 120°C for 2 minutes and cured at 50°C for 5 days, in the same manner as in Example 1, to obtain a gas barrier laminate sample.

[0081] Example 5 In Example 4, the coating amount of the overcoat paint was 4.92 g / m2 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 4, except that the thickness was adjusted to be as follows:

[0082] Example 6 In Example 4, the coating amount of the overcoat paint was 8.28 g / m 2 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 4, except that the thickness was adjusted to be as follows:

[0083] Example 7 In Example 4, the coating amount of the overcoat paint was 10.45 g / m 2 A gas barrier laminate and an evaluation sample were obtained in the same manner as in Example 4, except that the thickness was adjusted to be as follows:

[0084] Example 8 For the overcoat paint, a thermosetting acrylic resin (B) (acrylic polyol, methyl methacrylate-isobornyl methacrylate (2-hydroxyethyl methacrylate) copolymer, solid content = 50%) was used and diluted with methyl ethyl ketone. Then, an isocyanate-based curing agent (C) (isocyanurate of pentamethylene diisocyanate, solid content = 100%) was added as a curing agent so that the amount was 9.0 parts by mass per 100 parts by mass of the solid content of the thermosetting acrylic resin, and the mixture was stirred for a predetermined time to prepare the overcoat paint. The above-mentioned overcoat paint was applied using a bar coater at a coating amount of 3.46 g / m 2 A sample of a gas barrier laminate was obtained in the same manner as in Example 4, except that the thickness was changed to be as follows.

[0085] Example 9 The above-mentioned barrier coating paint was applied to a substrate of 25 μm thick biaxially oriented polyester film (E5102 manufactured by Toyobo Co., Ltd.) using a bar coater at a coating weight of 2.0 g / m 2 The coating was then dried in a box oven at 200°C for 2 minutes. After that, a coating weight of 4.0 g / m was applied to the barrier coated surface. 2The urethane adhesive (Takenate A-315 / Takenate A-50 manufactured by Mitsui Chemicals, Inc.) was applied using a bar coater, dried using a dryer, and then the 25 μm thick biaxially oriented polyester film was laminated to produce a gas barrier laminate sample.

[0086] (Comparative Example 1) The above-mentioned barrier coating paint was applied to a substrate of 25 μm thick biaxially oriented polyester film (E5102 manufactured by Toyobo Co., Ltd.) using a bar coater at a coating weight of 2.0 g / m 2 The coating was then heated and dried in a box oven at 200°C for 2 minutes to obtain a sample of a gas barrier laminate.

[0087] (Comparative Example 2) Polyvinyl alcohol (saponification degree = 78-82 mol%, viscosity = 45 mPa·S (4%, 20°C), manufactured by Wako Pure Chemical Industries, Ltd.) was used as the overcoat paint, and diluted to 5 wt% with water. Next, 10.7 parts by mass of distilled water and 19.3 parts by mass of methanol were added to 70.0 parts by mass of this 5 wt% aqueous polyvinyl alcohol solution, and the mixture was stirred for a predetermined time to prepare the overcoat paint. The overcoat paint was applied using a bar coater at a coating amount of 0.54 g / m 2 The coating was then heated and dried in a box oven at 120°C for 3 minutes, and then further heat-treated at 210°C for 1 minute, in the same manner as in Example 1, to obtain a gas barrier laminate sample.

[0088] (Evaluation method) The gas barrier laminate and the evaluation samples were evaluated using the following evaluation methods, as shown in Table 1.

[0089] [Oxygen permeability] The oxygen permeability of each evaluation sample obtained in the examples and comparative examples was measured before and after the expansion / contraction test described below using an oxygen permeability measuring device (OX-TRAN2 / 22 manufactured by Modern Control) under the measurement conditions of a temperature of 40°C and a relative humidity of 90%.

[0090] [Water vapor permeability] The gas barrier property evaluation samples obtained in the Examples and Comparative Examples were measured before and after the expansion / contraction test described below using a water vapor transmission rate measuring device (PERMATRAN-W 3 / 34 manufactured by Modern Control) at a temperature of 40°C and a relative humidity of 90%.

[0091] [Optical properties] For each of the gas barrier laminates obtained in the examples and comparative examples, the total light transmittance (%) and haze (%) were measured using a haze meter (NDH8000 manufactured by Nippon Denshoku Industries Co., Ltd.) with the polyester film substrate side as the measurement detector side.

[0092] [Color measurement] For each of the gas barrier laminates obtained in the examples and comparative examples, the yellowness index (b* value) was measured in colorimetry (CIE 1976 L*a*b* color system) using a spectrophotometer / spectrocolorimeter (SQ7700 manufactured by Nippon Denshoku Industries Co., Ltd.) with the polyester film substrate side as the measurement detector side.

[0093] [Unloaded U-shaped expansion and contraction test of a planar object] For each of the gas barrier laminates obtained in the Examples and Comparative Examples, a no-load U-shaped expansion / contraction test for a planar body was carried out using a desktop durability tester DLDMHLH-FS (manufactured by Yuasa System Co., Ltd.) to evaluate flexibility. <Bending test measurement conditions> Measurement conditions: 200,000 bending times Reciprocating speed 60rpm Sample size: 10.3cm x 10.3cm

[0094] [Glass transition temperature measurement] The glass transition temperature of each of the organic coating layers obtained in the examples and comparative examples was measured using a differential scanning calorimeter series (DSC2500 manufactured by TA Instruments). Measurement conditions: Measurement temperature range -80 to 250°C Heating rate: 10℃ / min

[0095] Table 1 shows the results of various measurements and evaluations for the above examples and comparative examples.

[0096] [Table 1] [Abbreviations in Table 1] OC film thickness: film thickness of organic coating layer, TT: total light transmittance, Hz: haze, Tg: glass transition temperature [Industrial Applicability]

[0097] The gas barrier laminate of the present invention has excellent flexibility, and even when bent or stretched, the gas barrier layer is not damaged and excellent gas barrier properties can be maintained. Therefore, the gas barrier laminate can be suitably used for molded articles having curved surfaces, and can be suitably used for, but is not limited to, food packaging containers, pharmaceutical packaging materials, electronic devices, circuit materials, semiconductor applications, solar cells, organic electroluminescence (EL) devices, electronic paper, battery exteriors, and the like. [Explanation of symbols]

[0098] 1. Substrate, 2. Anchor coat layer, 3. Gas barrier layer, 4. Organic coating layer.

Claims

1. A gas barrier laminate comprising a substrate, a gas barrier layer containing at least an inorganic salt, and an organic coating layer formed on the gas barrier layer.

2. 2. The gas barrier laminate according to claim 1, wherein the organic coating layer is at least one selected from the group consisting of a coating film containing a thermosetting resin or a photocurable resin having a glass transition temperature of 70° C. or higher, and a thermoplastic resin film.

3. 3. The gas barrier laminate according to claim 2, wherein the thermosetting resin is an acrylic resin or a bisphenol A type epoxy resin.

4. 4. The gas barrier laminate according to claim 3, wherein the acrylic resin comprises at least one selected from the group consisting of methyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, and benzotriazole derivative acrylate.

5. 3. The gas barrier laminate according to claim 2, wherein the photocurable resin contains an acrylic compound.

6. 3. The gas barrier laminate according to claim 2, wherein the thermoplastic resin film is a polyester film.

7. 3. The gas barrier laminate according to claim 1, wherein the gas barrier layer comprises a reaction product obtained by reacting at least one of a metal alkoxide, a hydrolyzate of a metal alkoxide, and a metal hydroxide, a metal oxide, and a phosphate compound or a sulfate compound.

8. 8. The gas barrier laminate according to claim 7, wherein the metal species of the metal alkoxide and metal hydroxide is at least one of aluminum, titanium, iron, and zirconium.

9. 8. The gas barrier laminate according to claim 7, wherein the metal alkoxide is at least one of methoxide, ethoxide, propoxide, isopropoxide, butoxide, isobutoxide, sec-butoxide, and tert-butoxide.

10. 8. The gas barrier laminate according to claim 7, wherein the metal alkoxide is aluminum isopropoxide.

11. 8. The gas barrier laminate according to claim 7, wherein the metal hydroxide is aluminum hydroxide.

12. 8. The gas barrier laminate according to claim 7, wherein the metal oxide is zirconium oxide or aluminum oxide.

13. 8. The gas barrier laminate according to claim 7, wherein the phosphoric acid compound is at least one of orthophosphoric acid, metaphosphoric acid, polyphosphoric acid, and cyclic polyphosphoric acid.

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