Gas barrier laminate, coating liquid for producing the same, packaging material, package, and packaged article

Abstract

To provide a gas barrier laminate capable of withstanding a treatment under a high-temperature and high-humidity or high-temperature and high-pressure environment such as a retort treatment and a boil treatment, excellent in a maltreatment resistance capable of maintaining high-level gas barrier properties even if a maltreatment such as bending is applied thereafter, and also to provide a coating liquid for manufacturing thereof, a packaging material, a package and a packaged article.SOLUTION: A coating liquid for manufacturing a gas barrier laminate includes: a carboxyl group-containing polymer (a), a polyvalent metal-containing particle (b), a surfactant (c), a specific silicon-containing compound (d) and an organic solvent (e). In the coating liquid, an equivalence ratio of the polyvalent metal-containing particle (b) to the carboxyl group-containing polymer (a) is 0.45 to 0.9. A molar ratio of the specific silicon-containing compound (d) to the carboxyl group-containing polymer (a) is 0.7% to 7.5%.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas barrier laminate, a coating liquid for producing the same, a packaging material, a package, and a packaged article. [Background technology]

[0002] Food, medicine, cosmetics, agricultural chemicals, industrial products, and other items can deteriorate in quality due to oxygen when stored for long periods of time. For this reason, films and sheets with oxygen gas barrier properties are used as packaging materials for these items.

[0003] Conventionally, such packaging materials have often been provided with aluminum foil as a gas barrier coating layer. However, when using packaging materials containing aluminum foil, the contents cannot be visually confirmed, and metal detectors cannot be used. Therefore, particularly in the food and pharmaceutical fields, there has been a demand for the development of transparent packaging materials that have excellent gas barrier properties.

[0004] To meet these demands, gas barrier laminates have been developed in which a layer of polyvinylidene chloride (PVDC) is formed on a substrate by applying a coating liquid containing PVDC. The PVDC layer is transparent and has gas barrier properties.

[0005] However, there are concerns that PVDC generates dioxins when incinerated. Therefore, there has been a demand to switch from PVDC to non-chlorine-based materials. In response to this demand, for example, the use of polyvinyl alcohol (PVA)-based polymers instead of PVDC has been proposed.

[0006] A layer made of a PVA-based polymer is densified by hydrogen bonding of hydroxyl groups and exhibits high gas barrier properties in a low-humidity atmosphere. However, a layer made of a PVA-based polymer has a problem in that the hydrogen bonds loosen due to moisture absorption in a high-humidity atmosphere, significantly reducing the gas barrier properties. For this reason, gas barrier laminates using a PVA-based polymer layer as a gas barrier coating layer often cannot be used as packaging materials for foods containing a lot of moisture, and their use has been limited to packaging materials for dried foods, etc.

[0007] For the purpose of further improving the gas barrier property, it has been proposed to add an inorganic layered compound to a PVA polymer (see, for example, Patent Document 1). However, even if an inorganic layered compound is added, the water resistance of the PVA polymer itself is not improved, and the problem of reduced gas barrier property in a high-humidity atmosphere still remains.

[0008] In order to improve the gas barrier properties in a high-humidity atmosphere, it has been proposed to produce a gas barrier laminate by applying a coating liquid containing a PVA polymer and a polymer capable of forming a crosslinked structure with the PVA polymer to a substrate and then heat treating the substrate (see, for example, Patent Documents 2 and 3).

[0009] However, to achieve sufficient gas barrier properties using these techniques, heat treatment after application of the coating liquid is required, for example, at a high temperature of 150°C or higher to form a crosslinked structure. Such heat treatment causes severe deterioration of the substrate, for example, when the substrate is made of a polyolefin such as polypropylene (OPP) or polyethylene (PE). Therefore, there is a demand for gas barrier laminates that limit the substrate material or can be produced under milder conditions.

[0010] As a method for forming a gas barrier coating layer, a method has been proposed in which a layer containing a polycarboxylic acid polymer such as polyacrylic acid is formed and this polycarboxylic acid polymer is ionically crosslinked with polyvalent metal ions (see, for example, Patent Document 4).

[0011] This method does not require the high-temperature heat treatment performed in the methods described in Patent Documents 2 and 3. Therefore, polyolefin can be used as the substrate. Furthermore, the obtained gas barrier coating layer has excellent gas barrier properties even in a high-humidity atmosphere. Therefore, a gas barrier laminate including this gas barrier coating layer can also be used in applications that require heat sterilization treatment, such as boiling or retorting.

[0012] However, when a polycarboxylic acid polymer and a polyvalent metal compound are present in a coating solution, the polycarboxylic acid polymer and the polyvalent metal compound react with each other in the coating solution, easily causing precipitation. If precipitation occurs in the solution, a uniform film cannot be formed. Therefore, in this method, when forming a gas barrier coating layer, a layer containing a polycarboxylic acid polymer and a layer containing a polyvalent metal compound are separately formed. Therefore, when using this method, the number of steps increases because the gas barrier coating layer has a two-layer structure.

[0013] Patent Document 5 discloses a gas barrier film containing a polycarboxylic acid polymer and polyvalent metal compound particles in the same gas barrier coating layer. It proposes that the coating liquid used to form the gas barrier coating layer contains a polycarboxylic acid polymer, polyvalent metal compound particles, a surfactant, and an organic solvent, and the water content of the coating liquid is 1000 ppm or less. Because the water content of this coating liquid is 1000 ppm or less, the reaction between the polycarboxylic acid polymer and the polyvalent metal compound is suppressed.

[0014] The document describes that the use of the coating liquid makes it possible to form a film with excellent gas barrier properties under high-humidity conditions. However, there is a risk that the gas barrier properties of a laminate formed by applying this coating liquid will deteriorate if it is exposed to more severe conditions, specifically, a high-temperature, high-humidity or high-temperature, high-pressure atmosphere such as boiling or retort treatment, and then subjected to physical load (abuse) such as bending. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Publication No. 6-093133 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-289154 [Patent Document 3] Japanese Patent Application Laid-Open No. 2000-336195 [Patent Document 4] International Publication No. 2003 / 091317 [Patent Document 5] Japanese Patent Application Laid-Open No. 2005-126528 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention aims to provide a gas barrier laminate with excellent resistance to abuse, which can withstand treatments under high-temperature and high-humidity or high-temperature and high-pressure environments such as retort treatment and boiling treatment, and maintain a high level of gas barrier properties even when subjected to abuse such as bending thereafter, as well as a coating liquid, packaging material, package, and packaged article for use in producing the same. [Means for solving the problem]

[0017] According to a first aspect of the present invention, there is provided a composition comprising a carboxy group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), a silicon-containing compound (d), and an organic solvent (e), wherein the silicon-containing compound (d) is at least one selected from the group consisting of silane coupling agents represented by the following general formulas (1) and (2), their hydrolysates, and their condensates, and wherein the number of moles of carboxy groups contained in the carboxy group-containing polymer (a) (a t ) the equivalent ratio b of the product (bt) of the number of moles and the valence of the polyvalent metal contained in the polyvalent metal-containing particles (b) to t / a t is 0.45 or more and 0.9 or less, and the number of moles of the carboxyl group (a t The number of moles of the silicon-containing compound (d) relative to the t ) molar ratio d t / a tThe coating liquid for producing a gas barrier laminate is provided with a molar ratio d t / a t in d t is the number of moles of the silicon-containing compound (d) converted into the silane coupling agent. Si(OR1)3Z1…(1) Si(R2)(OR3)2Z2…(2) In general formula (1), R1 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z1 is a group containing an epoxy group. In general formula (2), R2 is a methyl group, R3 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z2 is a group containing an epoxy group.

[0018] According to a second aspect of the present invention, there is provided the coating liquid according to the first aspect, wherein the carboxy group-containing polymer (a) contains at least a structural unit derived from at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

[0019] According to a third aspect of the present invention, there is provided a coating liquid according to the first or second aspect, in which the polyvalent metal contained in the polyvalent metal-containing particles (b) is a divalent metal.

[0020] According to a fourth aspect of the present invention, there is provided a gas barrier laminate comprising a substrate, and an inorganic vapor-deposited layer containing an inorganic oxide and a coating layer, in this order, on at least one main surface of the substrate, wherein the coating layer contains a carboxy group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), and a silicon-containing compound (d), the silicon-containing compound (d) being at least one selected from the group consisting of silane coupling agents represented by the following general formulas (1) and (2), their hydrolysates, and their condensates, and the number of moles of carboxy groups contained in the carboxy group-containing polymer (a) (a t ) the equivalent ratio b of the product (bt) of the number of moles and the valence of the polyvalent metal contained in the polyvalent metal-containing particles (b) tot / a t is 0.45 or more and 0.9 or less, and the number of moles of the carboxyl group (a t The number of moles of the silicon-containing compound (d) relative to the t ) molar ratio d t / a t The gas barrier laminate has a molar ratio d of 0.7% or more and 7.5% or less. t / a t in d t is the number of moles of the silicon-containing compound (d) converted into the silane coupling agent. Si(OR1)3Z1…(1) Si(R2)(OR3)2Z2…(2) In general formula (1), R1 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z1 is a group containing an epoxy group. In general formula (2), R2 is a methyl group, R3 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z2 is a group containing an epoxy group.

[0021] According to a fifth aspect of the present invention, there is provided the gas barrier laminate according to the fourth aspect, wherein the carboxy group-containing polymer (a) contains at least a structural unit derived from at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

[0022] According to a sixth aspect of the present invention, there is provided the gas barrier laminate according to the fourth or fifth aspect, in which the polyvalent metal contained in the polyvalent metal-containing particles (b) is a divalent metal.

[0023] According to a seventh aspect of the present invention, there is provided the gas barrier laminate according to any one of the fourth to sixth aspects, wherein the coating layer has a thickness of 230 nm or more and 600 nm or less.

[0024] According to an eighth aspect of the present invention, there is provided the gas barrier laminate according to any one of the fourth to seventh aspects, further comprising an anchor coat layer between the substrate and the inorganic vapor deposition layer.

[0025] According to a ninth aspect of the present invention, there is provided a packaging material including the gas barrier laminate according to any one of the fourth to eighth aspects.

[0026] According to a tenth aspect of the present invention, there is provided a package including the packaging material according to the ninth aspect.

[0027] According to an eleventh aspect of the present invention, there is provided a packaged article including the package according to the tenth aspect and contents contained in the package. [Effects of the Invention]

[0028] According to the present invention, it is possible to provide a gas barrier laminate with excellent resistance to abuse, which can withstand treatments under high temperature and high humidity or high temperature and high pressure environments such as retort treatment and boiling treatment, and can maintain a high level of gas barrier properties even when subjected to abuse such as bending thereafter, as well as a coating liquid, packaging material, package, and packaged article for use in producing the same. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a cross-sectional view schematically showing a gas barrier laminate according to one embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view schematically showing a gas barrier laminate according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present embodiment will be described below with reference to the drawings. Elements having the same or similar functions are given the same reference numerals, and redundant description will be omitted.

[0031] <Coating liquid for manufacturing gas barrier laminates> The coating liquid for producing a gas barrier laminate according to an embodiment of the present invention (hereinafter referred to as "the coating liquid according to this embodiment" or simply "the coating liquid") is suitably used for forming a coating layer of a gas barrier laminate, and is suitably used for forming, for example, the coating layer 3 in the gas barrier laminates 10 and 20 shown in Fig. 1 or 2 described below. Hereinafter, the layer obtained by drying a coating film made from the coating liquid according to this embodiment may be referred to as "a coating layer derived from the coating liquid" or simply "a coating layer".

[0032] The coating liquid according to this embodiment contains a carboxyl group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), a silicon-containing compound (d), and an organic solvent (e). In this embodiment, the polyvalent metal-containing particles (b) are in a state where the number of moles of carboxyl groups contained in the carboxyl group-containing polymer (a) (a t ) is the equivalent ratio b of the product (bt) of the number of moles of the polyvalent metal contained in the polyvalent metal-containing particles (b) and the valence t / a t The silicon-containing compound (d) is contained in the coating liquid at a blending ratio of 0.45 to 0.9. t The number of moles of silicon-containing compound (d) relative to t ) molar ratio d t / a t is contained in the coating liquid at a blending ratio of 0.7% to 7.5%.

[0033] [Carboxy group-containing polymer (a)] The carboxyl group-containing polymer contained in the coating liquid according to this embodiment is a polymer having two or more carboxyl groups in the molecule, and is sometimes called a "polycarboxylic acid polymer." Representative examples of the carboxyl group-containing polymer include a homopolymer of a carboxyl group-containing unsaturated monomer, a copolymer of two or more types of carboxyl group-containing unsaturated monomers, a copolymer of a carboxyl group-containing unsaturated monomer and another polymerizable monomer, and a polysaccharide containing a carboxyl group in the molecule (also called a "carboxyl group-containing polysaccharide" or an "acidic polysaccharide").

[0034] The carboxy group includes not only a free carboxy group but also an acid anhydride group (specifically, a dicarboxylic acid anhydride group). The acid anhydride group may be partially ring-opened to form a carboxy group. A portion of the carboxy group may be neutralized with an alkali. In this case, the degree of neutralization is preferably 20% or less.

[0035] Here, the "degree of neutralization" is a value obtained by the following method. That is, the carboxyl groups can be partially neutralized by adding an alkali (f) to the carboxyl group-containing polymer (a). In this case, the ratio of the number of moles (Ft) of the alkali (F) to the number of moles (At) of the carboxyl groups contained in the carboxyl group-containing polymer (a) is the degree of neutralization.

[0036] In addition, a graft polymer obtained by graft polymerizing a carboxyl-containing unsaturated monomer onto a polymer not containing a carboxyl group, such as a polyolefin, can also be used as the carboxyl-containing polymer. A polymer obtained by hydrolyzing a polymer having a hydrolyzable ester group such as an alkoxycarbonyl group (e.g., a methoxycarbonyl group) to convert it into a carboxyl group can also be used.

[0037] The carboxyl group-containing unsaturated monomer is preferably an α,β-monoethylenically unsaturated carboxylic acid. Therefore, the carboxyl group-containing polymer includes a homopolymer of an α,β-monoethylenically unsaturated carboxylic acid, a copolymer of two or more α,β-monoethylenically unsaturated carboxylic acids, and a copolymer of an α,β-monoethylenically unsaturated carboxylic acid with another polymerizable monomer. A typical example of the other polymerizable monomer is an ethylenically unsaturated monomer.

[0038] Examples of α,β-monoethylenically unsaturated carboxylic acids include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid; unsaturated dicarboxylic anhydrides such as maleic anhydride and itaconic anhydride; and mixtures of two or more of these. Among these, at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid is preferred, and at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, and maleic acid is more preferred.

[0039] Other polymerizable monomers copolymerizable with α,β-monoethylenically unsaturated carboxylic acids, particularly ethylenically unsaturated monomers, include, for example, ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; saturated carboxylic acid vinyl esters such as vinyl acetate; acrylic acid alkyl esters such as methyl acrylate and ethyl acrylate; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; chlorine-containing vinyl monomers such as vinyl chloride and vinylidene chloride; fluorine-containing vinyl monomers such as vinyl fluoride and vinylidene fluoride; unsaturated nitriles such as acrylonitrile and methacrylonitrile; aromatic vinyl monomers such as styrene and α-methylstyrene; and itaconic acid alkyl esters. These ethylenically unsaturated monomers can be used alone or in combination of two or more. Furthermore, when the carboxy group-containing polymer is a copolymer of an α,β-monoethylenically unsaturated carboxylic acid and a saturated carboxylic acid vinyl ester such as vinyl acetate, a copolymer obtained by saponifying this copolymer to convert the saturated carboxylic acid vinyl ester units into vinyl alcohol units can also be used.

[0040] Examples of carboxyl group-containing polysaccharides include acidic polysaccharides having a carboxyl group in the molecule, such as alginic acid, carboxymethylcellulose, and pectin. These acidic polysaccharides can be used alone or in combination of two or more. Acidic polysaccharides can also be used in combination with (co)polymers of α,β-monoethylenically unsaturated carboxylic acids.

[0041] When the carboxy group-containing polymer is a copolymer of an α,β-monoethylenically unsaturated carboxylic acid and another ethylenically unsaturated monomer, from the viewpoint of the gas barrier property, hot water resistance, and water vapor resistance of the resulting film, the proportion of the number of moles of the α,β-monoethylenically unsaturated carboxylic acid monomer to the total number of moles of those monomers in the copolymer is preferably 60 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

[0042] The carboxyl group-containing polymer is preferably a homopolymer or copolymer obtained by polymerization of only α,β-monoethylenically unsaturated carboxylic acid, since it is easy to obtain a film that has excellent gas barrier properties, moisture resistance, water resistance, hot water resistance, and water vapor resistance, and also has excellent gas barrier properties even in high-humidity environments. When the carboxyl group-containing polymer is a (co)polymer consisting of only α,β-monoethylenically unsaturated carboxylic acid, preferred examples include homopolymers, copolymers, and mixtures of two or more thereof obtained by polymerization of at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, maleic acid, fumaric acid, and itaconic acid. Among these, homopolymers and copolymers of at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, and maleic acid are more preferred.

[0043] As the carboxyl group-containing polymer, polyacrylic acid, polymethacrylic acid, polymaleic acid, and a mixture of two or more thereof are particularly preferred. As the acidic polysaccharide, alginic acid is preferred. Among these, polyacrylic acid is particularly preferred because it is relatively easy to obtain and can easily produce a film with excellent physical properties.

[0044] The number average molecular weight of the carboxy group-containing polymer is not particularly limited, but from the viewpoint of film formability and film physical properties, the number average molecular weight is preferably in the range of 2,000 to 10,000,000, more preferably in the range of 5,000 to 1,000,000, and even more preferably in the range of 10,000 to 500,000.

[0045] Here, the "number average molecular weight" is a value obtained by measurement using gel permeation chromatography (GPC). In GPC measurement, the number average molecular weight of a polymer is generally measured in terms of standard polystyrene.

[0046] [Polyvalent metal-containing particles (b)] The polyvalent metal-containing particles contained in the coating liquid according to this embodiment are particles containing one or more polyvalent metals whose metal ions have a valence of 2 or more. The polyvalent metal-containing particles may be particles made of a polyvalent metal whose metal ions have a valence of 2 or more, particles made of a compound of a polyvalent metal whose metal ions have a valence of 2 or more, or a mixture thereof.

[0047] Specific examples of polyvalent metals include, but are not limited to, metals in Group 2A of the short periodic table, such as beryllium, magnesium, and calcium; transition metals, such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, and zinc; and aluminum.

[0048] The polyvalent metal is preferably a divalent metal, and the polyvalent metal preferably forms a compound.

[0049] Specific examples of polyvalent metal compounds include, but are not limited to, oxides, hydroxides, carbonates, organic acid salts, and inorganic acid salts of polyvalent metals. Examples of organic acid salts include, but are not limited to, acetates, oxalates, citrates, lactates, phosphates, phosphites, hypophosphites, stearates, and monoethylenically unsaturated carboxylates. Examples of inorganic acid salts include, but are not limited to, chlorides, sulfates, and nitrates. Alkyl alkoxides of polyvalent metals can also be used as polyvalent metal compounds. These polyvalent metal compounds can be used alone or in combination of two or more.

[0050] Among polyvalent metal compounds, from the viewpoints of dispersion stability of the coating liquid and the gas barrier properties of the laminate formed from the coating liquid, compounds of beryllium, magnesium, calcium, copper, cobalt, nickel, zinc, aluminum, and zirconium are preferred, and compounds of divalent metals such as beryllium, magnesium, calcium, copper, zinc, cobalt, and nickel are more preferred.

[0051] Preferred divalent metal compounds include, but are not limited to, oxides such as zinc oxide, magnesium oxide, copper oxide, nickel oxide, and cobalt oxide; carbonates such as calcium carbonate; organic acid salts such as calcium lactate, zinc lactate, and calcium acrylate; and alkoxides such as magnesium methoxide.

[0052] The polyvalent metal or polyvalent metal compound is used as particles, and the particle shape is maintained in the coating liquid. From the viewpoints of dispersion stability of the coating liquid and the gas barrier properties of the laminate formed from the coating liquid, the average particle diameter of the polyvalent metal-containing particles in the coating liquid is preferably within the range of 10 nm to 10 μm (or 10,000 nm), more preferably within the range of 12 nm to 1 μm (or 1,000 nm), even more preferably within the range of 15 nm to 500 nm, and particularly preferably within the range of 15 nm to 50 nm.

[0053] If the average particle size of the polyvalent metal-containing particles in the coating solution is too large, the resulting coating layer tends to have insufficient uniformity in film thickness, surface flatness, and ionic crosslinking reactivity with the carboxyl group-containing polymer. If the average particle size of the polyvalent metal-containing particles is too small, the ionic crosslinking reaction with the carboxyl group-containing polymer may proceed prematurely. Furthermore, it is difficult to uniformly disperse ultrafine particles with a particle size of less than 10 nm in the coating solution.

[0054] When the sample is a dry solid, the average particle size of the polyvalent metal-containing particles can be measured by measuring and counting using a scanning electron microscope or a transmission electron microscope.The average particle size of the polyvalent metal-containing particles in the coating liquid can be measured by a light scattering method (Reference: "Fine Particle Engineering System", Vol. 1, pp. 362-365, Fuji Techno System (2001)).

[0055] The polyvalent metal-containing particles in the coating liquid exist as primary particles, secondary particles, or a mixture thereof, but in most cases, it is presumed that they exist as secondary particles in view of the average particle diameter.

[0056] [Surfactant (c)] In the coating liquid according to this embodiment, a surfactant is used to enhance the dispersibility of the polyvalent metal-containing particles. A surfactant is a compound having both a hydrophilic group and a lipophilic group in the molecule. Surfactants include anionic, cationic, and amphoteric ionic surfactants, as well as nonionic surfactants. Any surfactant may be used in the coating liquid.

[0057] Anionic surfactants include, for example, carboxylic acid type, sulfonic acid type, sulfate ester type, and phosphate ester type. Examples of carboxylic acid type anionic surfactants include aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates, N-acylsarcosinates, and N-acylglutamates. Examples of sulfonic acid type anionic surfactants include dialkyl sulfosuccinates, alkanesulfonates, alphaolefin sulfonates, linear alkylbenzene sulfonates, alkyl (branched)benzene sulfonates, naphthalene sulfonate-formaldehyde condensates, alkylnaphthalene sulfonates, and N-methyl-N-acyltaurates. Examples of sulfate ester type anionic surfactants include alkyl sulfates, polyoxyethylene alkyl ether sulfates, and fat sulfate esters. Examples of phosphate ester type anionic surfactants include alkyl phosphates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene alkylphenyl ether phosphates.

[0058] Examples of cationic surfactants include alkylamine salts and quaternary ammonium salts. Examples of alkylamine salt cationic surfactants include monoalkylamine salts, dialkylamine salts, and trialkylamine salts. Examples of quaternary ammonium salt cationic surfactants include alkyltrimethylammonium halide (chloride, bromide, or iodide) salts and alkylbenzalkonium chloride.

[0059] Examples of amphoteric surfactants include carboxybetaine type, 2-alkylimidazoline derivative type, glycine type, and amine oxide type. Examples of carboxybetaine type amphoteric surfactants include alkylbetaine and fatty acid amidopropyl betaine. Examples of 2-alkylimidazoline derivative type amphoteric surfactants include 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine. Examples of glycine type amphoteric surfactants include alkyl or dialkyldiethylenetriaminoacetic acid. Examples of amine oxide type amphoteric surfactants include alkylamine oxide.

[0060] Nonionic surfactants include, for example, ester type, ether type, ester ether type, and alkanolamide type. Ester type nonionic surfactants include, for example, glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester. Ether type nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, and polyoxyethylene polyoxypropylene glycol. Ester ether type nonionic surfactants include, for example, fatty acid polyethylene glycol and fatty acid polyoxyethylene sorbitan. Alkanolamide type nonionic surfactants include, for example, fatty acid alkanolamide. Surfactants having a polymer backbone, such as styrene-acrylic acid copolymers, can also be used.

[0061] Among these surfactants, anionic surfactants such as phosphate esters and surfactants having a polymer skeleton such as styrene-acrylic acid copolymers are preferred.

[0062] [Silicon-containing compound (d)] The coating liquid according to this embodiment contains a silicon-containing compound (d) to enhance the peel strength of the coating layer. The silicon-containing compound (d) contained in the coating liquid is at least one compound selected from the group consisting of a silane coupling agent represented by the following general formula (1), a silane coupling agent represented by the following general formula (2), their hydrolysates, and their condensates. Si(OR1)3Z1…(1) Si(R2)(OR3)2Z2…(2) In general formula (1), R1 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z1 is a group containing an epoxy group. In general formula (2), R2 is a methyl group, R3 may be the same or different and is an alkyl group having 1 to 6 carbon atoms, and Z2 is a group containing an epoxy group.

[0063] Silane coupling agents easily undergo hydrolysis and easily undergo condensation reactions in the presence of acid or alkali. Therefore, in the coating liquid, the silicon-containing compound rarely exists only in the form of the silane coupling agent represented by general formula (1) or (2), only in the form of its hydrolyzate, or only in the form of its condensate. That is, in the coating liquid according to this embodiment, the silicon-containing compound is usually present as a mixture of at least one of the silane coupling agent represented by general formula (1) and the silane coupling agent represented by general formula (2), its hydrolyzate, and its condensate.

[0064] Each of R1 in general formula (1) and R3 in general formula (2) may be an alkyl group having 1 to 6 carbon atoms, and is preferably a methyl group or an ethyl group. Each of Z1 in general formula (1) and Z2 in general formula (2) may be a group containing an epoxy group.

[0065] Specific examples of the silane coupling agent represented by general formula (1) or (2) include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane, with 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropyltrimethoxysilane being preferred. As the silane coupling agent, one type may be used, or two or more types may be used.

[0066] The hydrolysate of the silane coupling agent represented by general formula (1) or (2) may be a partial hydrolysate, a complete hydrolysate, or a mixture thereof.

[0067] The condensates contained as at least a portion of the silicon-containing compound in the coating liquid according to this embodiment are at least two of the following: a hydrolysis condensate of a silane coupling agent represented by general formula (1), a hydrolysis condensate of a silane coupling agent represented by general formula (2), and a condensate of a hydrolysis condensate of a silane coupling agent represented by general formula (1) and a hydrolysis condensate of a silane coupling agent represented by general formula (2). These hydrolysis condensates are produced by the following reaction: First, the silane coupling agent is hydrolyzed. As a result, one or more alkoxy groups contained in the silane coupling agent molecule are replaced with hydroxyl groups, resulting in a hydrolysis product. Subsequently, these hydrolysis products are condensed to form a compound in which a silicon atom (Si) is bonded via oxygen. This condensation is repeated to obtain a hydrolysis condensate.

[0068] [Organic solvent (e)] In the coating liquid according to the present embodiment, an organic solvent is used as a solvent or dispersion medium. Generally, a polar organic solvent capable of dissolving a carboxyl group-containing polymer is used as the organic solvent. However, an organic solvent having no polar group (heteroatom or atomic group having a heteroatom) may be used in combination with the polar organic solvent.

[0069] Examples of organic solvents that can be preferably used include alcohols such as methanol, ethanol, isopropanol, n-propanol, and n-butanol; and polar organic solvents such as dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetramethylurea, hexamethylphosphoric triamide, and γ-butyrolactone.

[0070] In addition to the polar organic solvents described above, hydrocarbons such as benzene, toluene, xylene, hexane, heptane, and octane; ketones such as acetone and methyl ethyl ketone; halogenated hydrocarbons such as dichloromethane; esters such as methyl acetate; and ethers such as diethyl ether can be used as appropriate. Hydrocarbons such as benzene that do not have a polar group are generally used in combination with a polar organic solvent.

[0071] The coating liquid according to this embodiment may contain only an organic solvent as a solvent or dispersion medium, or may further contain water. By adding water, the solubility of the carboxyl group-containing polymer can be improved, and the coatability and workability of the coating liquid can be improved. The water content of this coating liquid may be 100 ppm or more, 1,000 ppm or more, 1,500 ppm or more, or 2,000 ppm or more by mass fraction.

[0072] The water content of the coating liquid according to this embodiment is preferably 50,000 ppm or less, more preferably 10,000 ppm or less, and even more preferably 5,000 ppm or less, in terms of mass fraction.

[0073] 〔composition〕 The coating liquid according to this embodiment is a dispersion liquid containing a carboxyl group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), a silicon-containing compound (d), and an organic solvent (e), in which the polyvalent metal-containing particles (b) are dispersed.

[0074] Equivalent ratio of carboxyl group-containing polymer (a) to polyvalent metal-containing particles (b) In the coating liquid according to this embodiment, the polyvalent metal-containing particles (b) are contained in a compounding ratio such that the equivalent ratio to the carboxyl group-containing polymer (a) is 0.45 or more and 0.9 or less. Here, the equivalent ratio of the polyvalent metal-containing particles (b) to the carboxyl group-containing polymer (a) is the number of moles of carboxyl groups contained in the carboxyl group-containing polymer (a) (a t ) the product of the number of moles of the polyvalent metal contained in the polyvalent metal-containing particles (b) and the valence (b t ) ratio (b t ) / (a t )

[0075] In this embodiment, this equivalence ratio b t / a t is 0.45 or more and 0.9 or less, preferably 0.5 or more and 0.8 or less, and more preferably 0.6 or more and 0.7 or less. t / a t When the value of (a) is within the above range, crosslinking between the carboxyl group-containing polymer (a) and the polyvalent metal ions contained in the polyvalent metal-containing particles (b) proceeds appropriately, and a coating layer derived from the coating liquid that is neither too soft nor too hard is obtained, thereby improving the abuse resistance of the gas barrier laminate.

[0076] Equivalent ratio b of carboxyl group-containing polymer (a) to polyvalent metal-containing particles (b) t / a t can be determined, for example, as follows: An example will be described in which the carboxyl group-containing polymer (a) is polyacrylic acid and the polyvalent metal-containing particles (b) are magnesium oxide.

[0077] Polyacrylic acid has a molecular weight of 72 per monomer unit and one carboxyl group per monomer molecule. Therefore, the amount of carboxyl groups in 100 g of polyacrylic acid is 1.39 moles. The above equivalent ratio b in a coating solution containing 100 g of polyacrylic acid is t / a tis 1.0, this means that the coating solution contains magnesium oxide in an amount that neutralizes 1.39 moles of carboxyl groups. Therefore, the above equivalence ratio b t / a t To make the equivalent ratio b 0.6, it is sufficient to add magnesium oxide to the coating solution in an amount that neutralizes 0.834 moles of carboxyl groups. Here, the valence of magnesium is divalent, and the molecular weight of magnesium oxide is 40. Therefore, the above equivalent ratio b 0.6 in a coating solution containing 100 g of polyacrylic acid is t / a t To make the viscosity 0.6, 16.68 g (0.417 mol) of magnesium oxide should be added to this coating liquid.

[0078] Molar ratio of carboxyl group-containing polymer (a) to silicon-containing compound (d) In the coating liquid according to this embodiment, the silicon-containing compound (d) is contained in a blending ratio such that the molar ratio relative to the carboxyl group-containing polymer (a) is 0.7% or more and 7.5% or less. Here, the molar ratio of the silicon-containing compound (d) relative to the carboxyl group-containing polymer (a) refers to the number of moles of carboxyl groups contained in the carboxyl group-containing polymer (a) (a t The number of moles of silicon-containing compound (d) relative to t ) molar ratio d t / a t This molar ratio d t / a t In d t is the number of moles of the silicon-containing compound (d) converted into the silane coupling agent. t is the equivalent ratio b of the carboxyl group-containing polymer (a) to the polyvalent metal-containing particles (b) described above. t / a t in a t The number of moles is calculated using the same method as above.

[0079] In this embodiment, this molar ratio d t / a tis 0.7% or more and 7.5% or less, preferably 0.9% or more and 6.1% or less, and more preferably 2% or more and 5% or less. If the amount of silicon-containing compound (d) added is too small, the adhesion of the coating layer will be reduced and the resistance to abuse will decrease. On the other hand, if the amount of silicon-containing compound (d) added is too large, the silicon-containing compound itself will become a foreign matter, and the oxygen barrier property will deteriorate.

[0080] The surfactant (c) is used in an amount sufficient to stably disperse the polyvalent metal-containing particles (b). The concentration of the surfactant (c) in the coating liquid is usually in the range of 0.0001 to 70% by mass, preferably 0.001 to 60% by mass, and more preferably 0.1 to 50% by mass.

[0081] Without the addition of surfactant (c), it becomes difficult to disperse the polyvalent metal-containing particles (b) in the coating solution to a sufficiently small average particle size, which makes it difficult to obtain a coating solution in which the polyvalent metal-containing particles (b) are uniformly dispersed, and makes it difficult to form a coating film with a uniform thickness when applied to a substrate.

[0082] [Method for producing coating liquid] To produce a coating liquid, first, the carboxyl group-containing polymer (a) is uniformly dissolved in the organic solvent (e), and then the silicon-containing compound (d) is added thereto to prepare a carboxyl group-containing polymer solution.

[0083] On the other hand, polyvalent metal-containing particles (b), surfactant (c), and organic solvent (e) are mixed and, if necessary, subjected to a dispersion treatment to prepare a dispersion liquid. The dispersion treatment is performed so that the average particle diameter of the polyvalent metal-containing particles (b) reaches a predetermined value. If the average particle diameter of the polyvalent metal-containing particles (b) in the mixed liquid before the dispersion treatment is 10 μm or less, the dispersion treatment is not necessary; however, even in this case, the dispersion treatment is preferably performed. The dispersion treatment disaggregates the polyvalent metal-containing particles (b), stabilizing the coating liquid and improving the transparency of the gas barrier laminate obtained by applying the coating liquid. Furthermore, when the coating liquid is applied and the coating is dried, crosslinking between the carboxyl group-containing polymer (a) and polyvalent metal ions is facilitated, making it easier to obtain a gas barrier laminate with good gas barrier properties.

[0084] Dispersion methods include those using a high-speed stirrer, homogenizer, ball mill, or bead mill. Dispersion using a ball mill or bead mill can achieve high dispersion efficiency, and therefore a coating liquid with a stable dispersion state can be obtained in a relatively short time. In this case, the diameter of the balls or beads should be small, preferably 0.1 to 1 mm.

[0085] The coating liquid can be prepared by mixing the carboxyl group-containing polymer solution prepared as described above with the dispersion of polyvalent metal-containing particles. The silicon-containing compound (d) may be omitted from the carboxyl group-containing polymer solution. In this case, the silicon-containing compound (d) is mixed together with the carboxyl group-containing polymer solution and the dispersion of polyvalent metal-containing particles (b), for example.

[0086] In the coating liquid according to the present embodiment, the total concentration of components other than the organic solvent is preferably in the range of 0.1 to 60 mass %, more preferably 0.5 to 25 mass %, and particularly preferably 1 to 20 mass %, in order to obtain a coating film or a covering layer of a desired thickness with high workability.

[0087] The coating liquid according to the present embodiment may contain various additives, such as other polymers, thickeners, stabilizers, ultraviolet absorbers, antiblocking agents, softeners, inorganic layered compounds (e.g., montmorillonite), and colorants (dyes, pigments), as needed.

[0088] <Gas barrier laminate> The gas barrier laminate according to this embodiment comprises a substrate, and on at least one main surface of the substrate, an inorganic vapor deposition layer containing an inorganic oxide, and a coating layer, the coating layer being a coating layer derived from the coating liquid. Fig. 1 is a cross-sectional view schematically showing the gas barrier laminate according to this embodiment, and the gas barrier laminate 10 comprises a substrate 1, an inorganic vapor deposition layer 2 containing an inorganic oxide, and a coating layer 3.

[0089] [Base material] The substrate in the gas barrier laminate is not particularly limited, and various types can be used. The material constituting the substrate is not particularly limited, and various types can be used, for example, plastic or paper.

[0090] The substrate may be a single layer made of a single material, or may be a multi-layer made of multiple materials, such as a paper laminated with a plastic film, for example.

[0091] Of the above materials, plastic is preferred as the material for the substrate, since it can be molded into various shapes and can be given gas barrier properties, which further broadens the range of uses.

[0092] Examples of plastics include, but are not limited to, polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polybutylene terephthalate, and copolymers thereof; polyamide resins such as nylon-6, nylon-66, nylon-12, metaxylylene adipamide, and copolymers thereof; styrene resins such as polystyrene, styrene-butadiene copolymer, and styrene-butadiene-acrylonitrile copolymer; poly(meth)acrylic acid ester; polyacrylonitrile; polyvinyl acetate; ethylene-vinyl acetate copolymer; ethylene-vinyl alcohol copolymer; polycarbonate; polyarylate; regenerated cellulose; polyimide; polyetherimide; polysulfone; polyethersulfone; polyetherketone; and ionomer resins.

[0093] When the gas barrier laminate is used as a food packaging material, the substrate is preferably made of polyethylene, polypropylene, polyethylene terephthalate, nylon-6 or nylon-66.

[0094] As the plastic constituting the substrate, one type may be used alone, or two or more types may be blended and used.

[0095] The plastic may contain additives. The additives may be appropriately selected from known additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, and lubricants depending on the intended use. One type of additive may be used alone, or two or more types may be used in combination.

[0096] The form of the substrate is not particularly limited, and examples thereof include films, sheets, cups, trays, tubes, and bottles. Among these, films are preferred. When the substrate is a film, the film may be a stretched film or an unstretched film.

[0097] There are no particular restrictions on the thickness of the substrate, but from the viewpoint of the mechanical strength and processability of the resulting gas barrier laminate, it is preferably in the range of 1 to 200 μm, more preferably in the range of 5 to 100 μm.

[0098] The surface of the substrate may be subjected to plasma treatment, corona treatment, ozone treatment, flame treatment, or radical activation treatment using ultraviolet (UV) or electron beams, etc., so that the coating liquid can be applied without being repelled by the substrate. The treatment method is appropriately selected depending on the type of substrate.

[0099] [Inorganic vapor deposited layer] The gas barrier laminate according to this embodiment includes an inorganic vapor deposition layer between the substrate and the coating layer, which can further enhance the gas barrier properties of the gas barrier laminate including the coating layer.

[0100] The inorganic vapor deposition layer contains an inorganic oxide. Examples of inorganic oxides include aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. Among these, aluminum oxide, silicon oxide, magnesium oxide, or a mixture of two or more of these is preferred from the viewpoint of achieving both transparency and gas barrier properties.

[0101] The thickness of the inorganic vapor deposition layer may be, for example, in the range of 5 to 100 nm, or may be in the range of 10 to 50 nm. A thickness of 5 nm or more is preferable from the viewpoint of forming a uniform thin film. If the thin film serving as a gas barrier material is uniform, it can fully perform the functions required of the gas barrier material. A thickness of 100 nm or less is preferable from the viewpoint of the flexibility of the thin film. If the flexibility of the gas barrier material is poor, cracks may occur due to external factors such as bending or pulling.

[0102] [Coating layer] The coating layer is formed from the above-mentioned coating liquid, specifically, by applying the above-mentioned coating liquid to the inorganic vapor deposition layer and drying the coating film. As described above, this coating layer is formed by the equivalent ratio b of the polyvalent metal-containing particles (b) to the carboxyl group-containing polymer (a). t / a t , and the molar ratio d of the silicon-containing compound (d) to the carboxyl group-containing polymer (a) t / a t The gas barrier laminate according to this embodiment is provided with a coating layer derived from the above-mentioned coating liquid, and therefore exhibits excellent abuse resistance, capable of withstanding treatments under high temperature and high humidity or high temperature and pressure environments, such as retort treatment and boiling treatment, and maintaining a high level of gas barrier properties even when subjected to abuse such as bending thereafter.

[0103] From the viewpoint of gas barrier properties and abuse resistance after high-temperature and high-pressure treatment, the thickness of the coating layer is preferably 230 nm or more and 600 nm or less, more preferably 270 nm or more and 520 nm or less, and even more preferably 300 nm or more and 450 nm or less.

[0104] [Other layers] The gas barrier laminate according to this embodiment may further include one or more layers other than the substrate, inorganic vapor deposition layer, and coating layer, as necessary. For example, the gas barrier laminate according to this embodiment may have only the coating layer described above as the gas barrier coating layer, or may further include one or more other layers in addition to the coating layer. For example, a layer made of an inorganic compound such as aluminum oxide, silicon oxide, or aluminum may be formed on the surface of the substrate by sputtering, ion plating, or the like.

[0105] The gas barrier laminate according to this embodiment may further include an anchor coat layer between the substrate and the inorganic vapor deposition layer, or between the inorganic vapor deposition layer and the coating layer, for the purposes of increasing adhesion between the layers or enabling the coating liquid for forming the coating layer to be applied without being repelled by the inorganic vapor deposition layer.

[0106] Fig. 2 is a cross-sectional view schematically showing a gas barrier laminate according to another embodiment of the present invention. The gas barrier laminate 20 shown in Fig. 2 further comprises an anchor coat layer 4 between the substrate 1 and the inorganic vapor deposition layer 2, in addition to the gas barrier laminate 10 shown in Fig. 1 described above.

[0107] The anchor coat layer can be formed by a conventional method using a known anchor coat liquid, such as a resin containing polyurethane resin, acrylic resin, melamine resin, polyester resin, phenol resin, amino resin, or fluororesin.

[0108] In addition to the resin, the anchor coating liquid may further contain an isocyanate compound for the purpose of improving adhesion and hot water resistance. The isocyanate compound may be any compound having one or more isocyanate groups in the molecule, and examples thereof include hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and tolylene diisocyanate. The anchor coating liquid may further contain a liquid medium for dissolving or dispersing the resin and the isocyanate compound.

[0109] The thickness of the anchor coat layer is not particularly limited. The thickness of the anchor coat layer may be, for example, in the range of 0.01 to 2 μm, or may be in the range of 0.05 to 1 μm. If the thickness is less than 0.01 μm, the layer is so thin that it may not fully exhibit its performance as an anchor coat layer. On the other hand, a thickness of 2 μm or less is preferable from the viewpoint of flexibility. If the flexibility is reduced, cracks may occur in the anchor coat layer due to external factors.

[0110] The gas barrier laminate according to this embodiment may, if necessary, further comprise another layer laminated via an adhesive onto the coating layer, or onto the surface of the substrate or the inorganic vapor deposition layer, or may further comprise another layer formed by extrusion lamination of an adhesive resin.

[0111] The other laminated layers can be appropriately selected depending on the purpose, such as imparting strength, sealing properties, easy opening when sealed, design, light blocking properties, moisture resistance, etc., and are not particularly limited, and examples thereof include those made of the same material as the plastics described above for the substrate. In addition, paper, aluminum foil, etc. may also be used.

[0112] The thickness of the other layer to be laminated is preferably in the range of 1 to 1000 μm, more preferably in the range of 5 to 500 μm, even more preferably in the range of 5 to 200 μm, and particularly preferably in the range of 5 to 150 μm. The number of other layers to be laminated may be one or more.

[0113] The gas barrier laminate according to this embodiment may further include a printed layer, if necessary. The printed layer may be formed on a coating layer provided on the substrate, or may be formed on the surface of the substrate on which no coating layer is provided. Furthermore, when another layer is laminated, the printed layer may be formed on the other layer to be laminated.

[0114] [Method for producing gas barrier laminate] The gas barrier laminate according to this embodiment can be produced by a production method including a step of forming an inorganic vapor deposition layer and a step of forming a coating layer using the above-described coating liquid. This production method may further include a step of forming other layers such as an anchor coat layer and / or a step of forming a printing layer, as necessary.

[0115] As an example of a method for producing the gas barrier laminate according to this embodiment, a method for producing the gas barrier laminate 20 shown in FIG. 2 will be described below. In the method for producing the gas barrier laminate 20, the anchor coat layer 4 is formed on the substrate 1. The anchor coat layer 4 can be formed by applying the anchor coat liquid described above to the substrate 1 and drying the formed coating film. There are no particular limitations on the method for applying the anchor coat liquid, and it can be carried out using well-known printing methods such as offset printing, gravure printing, and silk screen printing, or well-known coating methods such as roll coating, knife edge coating, and gravure coating. By drying the formed coating film, the solvent is removed and hardening proceeds, forming the anchor coat layer 4.

[0116] In the method for producing the gas barrier laminate 20, the inorganic vapor deposition layer 2 is formed on the anchor coat layer 4. Various methods are known for forming the inorganic vapor deposition layer 2, such as vacuum deposition, sputtering, ion plating, and chemical vapor deposition (CVD), and any of these methods may be used, but it is common to form the inorganic vapor deposition layer by vacuum deposition.

[0117] The heating means of the vacuum deposition apparatus used in the vacuum deposition method may be an electron beam heating method, a resistance heating method, an induction heating method, or the like, and any of these may be used.

[0118] Furthermore, in order to improve the adhesion of the inorganic vapor deposition layer 2 to the anchor coat layer 4 and the density of the inorganic vapor deposition layer 2, a plasma assisted method or an ion beam assisted method can also be used.

[0119] In order to increase the transparency of the inorganic vapor deposition layer 2, reactive vapor deposition may be performed by blowing oxygen gas or the like during vapor deposition.

[0120] In the method for producing the gas barrier laminate 20, the coating layer 3 is formed on the inorganic vapor deposition layer 2. The coating layer 3 can be formed by applying the above-mentioned coating liquid onto the inorganic vapor deposition layer 2 and drying the resulting coating film.

[0121] The method for applying the coating liquid is not particularly limited, but examples include methods using an air knife coater, a direct gravure coater, a gravure offset coater, an arc gravure coater, a reverse roll coater such as a top feed reverse coater, a bottom feed reverse coater, or a nozzle feed reverse coater, a five-roll coater, a lip coater, a bar coater, a bar reverse coater, or a die coater.

[0122] The method for drying the coating film is not particularly limited, but examples thereof include natural drying, drying in an oven set at a predetermined temperature, and using a dryer attached to a coater, such as an arch dryer, floating dryer, drum dryer, or infrared dryer.

[0123] Drying conditions can be appropriately selected depending on the drying method, etc. For example, in a method of drying in an oven, the drying temperature is preferably in the range of 40 to 150°C, more preferably in the range of 45 to 150°C, and particularly preferably in the range of 50 to 140°C. The drying time varies depending on the drying temperature, but is preferably in the range of 0.5 seconds to 10 minutes, more preferably in the range of 1 second to 5 minutes, and particularly preferably in the range of 1 second to 1 minute.

[0124] It is believed that during or after drying, the carboxyl group-containing polymer (a) and the polyvalent metal-containing particles (b) contained in the coating film react with each other to introduce an ionic crosslinking structure. To allow the ionic crosslinking reaction to proceed sufficiently, the dried film is preferably aged in an atmosphere with a relative humidity of preferably 20% or more, more preferably 40 to 100%, at a temperature of preferably 5 to 200°C, more preferably 20 to 150°C, for about 1 second to 10 days.

[0125] The gas barrier laminate obtained in this manner is ionically crosslinked, and therefore has excellent moisture resistance, water resistance, hot water resistance, and water vapor resistance. This gas barrier laminate also has excellent gas barrier properties after treatment in a high-temperature, high-humidity or high-temperature, high-pressure environment, such as retort treatment or boiling treatment, and exhibits excellent abuse resistance, maintaining a high level of gas barrier properties even when subjected to abuse such as bending after the above treatment.

[0126] <Packaging materials, packages and packaged articles> The packaging material according to this embodiment includes the gas barrier laminate described above. This packaging material is used, for example, to produce a package for packaging an article.

[0127] The packaging body according to this embodiment includes the packaging material described above. This package may be made of the above-mentioned packaging material, or may include the above-mentioned packaging material and other components. In the former case, the package is, for example, the above-mentioned packaging material formed into a bag. In the latter case, the package is, for example, a container including the above-mentioned packaging material as a lid and a cylindrical container body with a bottom.

[0128] In this package, the packaging material may be a molded article. As described above, this molded article may be a container such as a bag, or a part of a container such as a lid. Specific examples of the package or a part thereof include a bag, a pouch with a spout, a laminated tube, an infusion bag, a container lid, and a paper container.

[0129] There is no particular limitation on the application of this packaging material, and this packaging material can be used to package a variety of items.

[0130] The packaged article according to this embodiment includes the above-described package and contents contained therein.

[0131] As described above, the gas barrier laminate according to this embodiment has excellent gas barrier properties and abuse resistance even after high-temperature, high-humidity treatment or high-temperature, high-pressure treatment, such as boiling and retort treatment. Therefore, packaging materials and packages containing this gas barrier laminate are preferably used as packaging materials and packages for items that are susceptible to deterioration due to the effects of oxygen and water vapor, particularly as packaging materials and packages for food. These packaging materials and packages are also preferably used as packaging materials and packages for packaging industrial materials, such as agricultural chemicals, medicines, and other chemicals, medical devices, machine parts, and precision materials.

[0132] When the gas barrier laminate is subjected to heat sterilization treatment such as boiling or retort treatment, the gas barrier properties and interlayer adhesion do not deteriorate but tend to improve. Therefore, the packaging material and packaging body may be a packaging material for heat sterilization and a packaging body for heat sterilization, respectively.

[0133] The packaging material for heat sterilization and the package for heat sterilization are used to package articles that are to be subjected to heat sterilization treatment after packaging. Examples of products that are heat sterilized after packaging include foods such as curry, stew, soup, sauce, and processed meat products.

[0134] Examples of heat sterilization treatment include boiling treatment and retort treatment. Boiling is a moist heat sterilization process for preserving foods and the like. In boiling, a packaged item containing food or other contents packaged in the above-mentioned package is typically subjected to moist heat sterilization at atmospheric pressure at a temperature of 60 to 100°C for 10 to 120 minutes, although this depends on the contents. Boiling is usually carried out using a hot water bath. There are two types of boiling: a batch type in which the packaged item is immersed in a hot water bath at a constant temperature and removed after a certain period of time, and a continuous type in which the packaged item is sterilized by passing it through a hot water bath in a tunnel-like manner.

[0135] Retort processing is a process of sterilizing microorganisms such as mold, yeast, and bacteria by pressurizing and heating in order to generally preserve foods, etc. In retort processing, a packaged product obtained by packaging food in the above-mentioned package is typically subjected to pressure sterilization and heat treatment at a temperature of 105 to 140°C under a pressure of 0.15 to 0.3 MPa for 10 to 120 minutes. Retort apparatuses include steam types that use heated steam and hot water types that use pressurized superheated water, and these are used appropriately depending on the sterilization conditions of the food, etc., that will be contained therein. [Example]

[0136] Specific examples of the present invention will be described below. <Preparation of coating solution> (Comparative Example 1: Coating Liquid 1-1) A carboxyl group-containing polymer was dissolved in isopropanol under heating. Polyacrylic acid (PAA) (Jurymer (registered trademark) AC-10LP, number average molecular weight 50,000, manufactured by Toagosei Co., Ltd.) was used as the carboxyl group-containing polymer. In this way, a polyacrylic acid solution containing polyacrylic acid at a concentration of 10% by mass was prepared.

[0137] 1.8 g of polyether phosphate ester (Disparlon (registered trademark) DA-375, manufactured by Kusumoto Chemical Industries Co., Ltd., solid content 100% by mass) was dissolved in 26.2 g of isopropanol. Next, 12 g of zinc oxide (FINEX (registered trademark)-30, manufactured by Sakai Chemical Industry Co., Ltd.) with an average primary particle diameter of 35 nm was added to this and stirred. The resulting solution was dispersed for 1 hour using a planetary ball mill (P-7, manufactured by Fritsch). Zirconia beads with a diameter of 0.2 mm were used for this dispersion treatment. The beads were then sieved from this solution to obtain a dispersion containing zinc oxide at a concentration of 30% by mass.

[0138] Next, 50.00 g of polyacrylic acid (PAA) solution, 3.77 g of zinc oxide dispersion, 0.10 g of a silane coupling agent (SC agent) (KBM-403, 3-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) as a silicon-containing compound, and 22.86 g of isopropanol were mixed to prepare coating solution 1-1. In this coating solution 1-1, the number of moles of carboxyl groups contained in polyacrylic acid (PAA) (a t ) versus the product of the number of moles of zinc contained in zinc oxide and the valence (b t ) equivalent ratio b t / a t is 0.4, and the number of moles of carboxyl groups contained in polyacrylic acid (PAA) (a t ) to the number of moles of SC agent (d t ) molar ratio d t / a t was 0.6%.

[0139] (Comparative Examples 2 to 4: Coating Liquids 1-2 to 1-4) Coating solutions 1-2 to 1-4 were prepared in the same manner as described above for coating solution 1-1, except that the amount of the SC agent added was changed to the amount shown in Table 1. The equivalent ratio b t / a t , and molar ratio d t / a t is as shown in Table 1.

[0140] (Comparative Example 5: Coating Liquid 2-1) Coating liquid 2-1 was prepared in the same manner as described above for coating liquid 1-1, except that the amount of zinc oxide dispersion added was changed to 4.71 g and the amount of isopropanol added was changed to 25.45 g. t / a t is 0.5, and the molar ratio d t / a t was 0.6%.

[0141] (Examples 1 and 2, Comparative Example 6: Coating Liquids 2-2 and 2-4) Coating solutions 2-2 to 2-4 were prepared in the same manner as described above for coating solution 2-1, except that the amount of the SC agent added was changed to the amount shown in Table 1. The equivalent ratio b t / a t , and molar ratio d t / a t is as shown in Table 1.

[0142] (Comparative Example 7: Coating Liquid 3-1) Coating solution 3-1 was prepared in the same manner as described above for coating solution 1-1, except that the amount of zinc oxide dispersion added was changed to 7.54 g and the amount of isopropanol added was changed to 33.22 g. t / a t is 0.8, and the molar ratio d t / a t was 0.6%.

[0143] (Examples 3 to 4, Comparative Example 8: Coating Liquids 3-2 to 3-4) Coating solutions 3-2 to 3-4 were prepared in the same manner as described above for coating solution 3-1, except that the amount of the SC agent added was changed to the amount shown in Table 1. The equivalent ratio b t / a t , and molar ratio d t / a t is as shown in Table 1.

[0144] (Comparative Example 9: Coating Liquid 4-1) Coating solution 4-1 was prepared in the same manner as described above for coating solution 1-1, except that the amount of zinc oxide dispersion added was changed to 9.42 g and the amount of isopropanol added was changed to 38.40 g. t / a t is 1.0, and the molar ratio d t / a t was 0.6%.

[0145] (Comparative Examples 10 to 12: Coating Liquids 4-2 to 4-4) Coating solutions 4-2 to 4-4 were prepared in the same manner as described above for coating solution 4-1, except that the amount of the SC agent added was changed to the amount shown in Table 1. The equivalent ratio b t / a t , and molar ratio d t / a t is as shown in Table 1.

[0146] [Table 1]

[0147] <Production of Gas Barrier Laminate> (Preparation of anchor coat solution) In a dilution solvent (ethyl acetate), 1 part by mass of γ-isocyanatopropyltrimethoxysilane and 5 parts by mass of acrylic polyol were mixed and stirred. Next, tolylene diisocyanate (TDI) was added as an isocyanate compound so that the amount of NCO groups was equal to the amount of OH groups in the acrylic polyol. The resulting mixed solution was diluted with the dilution solvent to a concentration of 2% by mass to obtain anchor coating solution 1. As the acrylic polyol, GS-5756 manufactured by Mitsubishi Rayon Co., Ltd. was used.

[0148] Example 101 Anchor coating solution 1 was applied to one side of a biaxially oriented polypropylene film (manufactured by Mitsui Chemicals Tohcello Co., Ltd., product name: ME-1, thickness 20 μm) using a bar coater so that the thickness after drying would be 0.2 μm, and the film was dried at 150°C for 1 minute to form an anchor coating layer.

[0149] Silicon was evaporated onto this anchor coat layer using a vacuum deposition device that uses electron beam heating, and oxygen gas was then introduced thereto to deposit silicon oxide (SiO) to form an inorganic deposition layer with a thickness of 20 nm.

[0150] Coating liquid 2-2 was applied onto this inorganic vapor deposition layer using a bar coater (wire bar). This coating film was dried in an oven at 50°C for 1 minute to form a coating layer with a thickness of 400 nm. In this way, laminate 1 was obtained. The thickness of the coating layer was measured by the method described below.

[0151] [Examples 102 to 104] Laminates 2, 3, and 4 were produced in the same manner as for laminate 1 in Example 101, except that coating liquid 2-2 was changed to coating liquids 2-3, 3-2, and 3-3, respectively.

[0152] [Examples 105 to 106] Laminates 5 and 6 were produced in the same manner as for Laminate 3 in Example 103, except that the thickness of the coating layer was changed from 400 nm to 230 nm or 600 nm, respectively.

[0153] [Comparative Examples 101 to 112] Laminates 1C to 12C were produced in the same manner as for laminate 1 in Example 101, except that coating liquid 2-2 was changed to coating liquids 1-1 to 1-4, 2-1, 2-4, 3-1, 3-4, and 4-1 to 4-4, respectively.

[0154] <Measurement of coating layer thickness> Each laminate was embedded in an embedding resin, and the cross section was exposed using a microtome, and the cross section of the laminate was observed using a scanning electron microscope (SEM). From the SEM images, the thickness of the coating layer on the flat surface was measured at 10 points and the average value was calculated, which was used as the thickness of the coating layer.

[0155] <Evaluation> [Oxygen permeability after retort processing] Each obtained laminate was cut into a size of 20 cm x 20 cm and retorted for 30 minutes at 0.2 MPa and 120°C using a hot water storage retort kettle. The oxygen permeability of each sample after retort treatment was measured using an oxygen permeability tester OX-TRAN (registered trademark) 2 / 20 manufactured by Modern Control under conditions of a temperature of 30°C and a relative humidity of 70%. The measurement method was in accordance with JIS K-7126 Method B (constant pressure method) and ASTM D3985, and the measured values ​​are in units of cc / m 2 / day / atm. Oxygen permeability is 10cc / m 2 / day / atm or less is A, 10cc / m 2 / day / atm is rated as B. Oxygen permeability is 10cc / m 2 When the gas barrier strength is 1 / day / atm or less, the laminate has the desired gas barrier properties after high-temperature, high-pressure, and high-temperature, high-humidity treatments. These results are shown in Table 2.

[0156] [Oxygen permeability after retort treatment and bending abuse test] After the retort test, each laminate was subjected to five bending cycles using a Gelbo Flex Tester manufactured by Tester Industries, as specified in MIL B131 (ASTMF392). The oxygen permeability of each laminate after the abuse test was measured under the same conditions and method as above. The oxygen permeability was measured when the oxygen permeability was 10 cc / m or less. 2 / day / atm or less is A, 10cc / m 2 / day / atm is rated as B. Oxygen permeability is 10cc / m 2 When the gas barrier strength is 1 / day / atm or less, the laminate can withstand treatment in high-temperature, high-humidity and high-temperature, high-pressure environments, and can maintain a high level of gas barrier properties even when subjected to subsequent abuse, demonstrating excellent abuse resistance. These results are shown in Table 2.

[0157] [Table 2]

[0158] As shown in Table 2, laminates 1 to 6 (Examples 101 to 106) according to this embodiment not only have excellent gas barrier properties after high temperature and high humidity and high temperature and high pressure treatment, but also have excellent abuse resistance, which allows them to maintain high gas barrier properties even when subjected to abuse such as bending thereafter.

[0159] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0160] 1...Base material 2...Inorganic vapor deposition layer 3...Covering layer 4. Anchor coat layer 10, 20 Gas barrier laminate

Claims

1. The present invention comprises a carboxy group-containing polymer (a), polyvalent metal-containing particles (b) containing zinc as the polyvalent metal, a surfactant (c), a silicon-containing compound (d), and an organic solvent (e), wherein the silicon-containing compound (d) is at least one selected from the group consisting of silane coupling agents represented by the following general formulas (1) and (2), hydrolysates thereof, and condensates thereof, and the number of moles of carboxy groups contained in the carboxy group-containing polymer (a) (a ｔ ) the equivalent ratio b of the product (bt) of the number of moles of the polyvalent metal contained in the polyvalent metal-containing particles (b) and the valence ｔ / a ｔ is 0.45 or more and 0.9 or less, and the number of moles of the carboxyl group (a ｔ The number of moles of the silicon-containing compound (d) relative to the ｔ ) molar ratio d ｔ / a ｔ A coating solution for producing a gas barrier laminate, wherein the molar ratio d ｔ / a ｔ d in ｔ is the number of moles of the silicon-containing compound (d) converted into the silane coupling agent. Si(OR １ ) ３ Z １ …(1) Si(R ２ )(OR ３ ) ２ Z ２ …(2) In general formula (1), R １ are alkyl groups having 1 to 6 carbon atoms, which may be the same or different, and Z １ is a group containing an epoxy group, and in general formula (2), R ２ is a methyl group, and R ３ are alkyl groups having 1 to 6 carbon atoms, which may be the same or different, and Z ２ is a group containing an epoxy group.

2. 2. The coating liquid according to claim 1, wherein the carboxy group-containing polymer (a) contains at least a structural unit derived from at least one α,β-monoethylenically unsaturated carboxylic acid selected from the group consisting of acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, and fumaric acid.

3. 3. A gas barrier laminate comprising a substrate, and on at least one main surface of the substrate, an inorganic vapor deposition layer containing an inorganic oxide, and a coating layer, in this order, wherein the coating layer is a dried film of a coating film made from the coating liquid according to claim 1 or 2.

4. The gas barrier laminate according to claim 3 , wherein the coating layer has a thickness of 230 nm or more and 600 nm or less.

5. 5. The gas barrier laminate according to claim 3, further comprising an anchor coat layer between the substrate and the inorganic vapor deposition layer.

6. A packaging material comprising the gas barrier laminate according to any one of claims 3 to 5.

7. A package comprising the packaging material of claim 6.

8. A packaged article comprising the package according to claim 7 and contents contained in the package.

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