Gas barrier laminate, packaging material, package, and packaged article

Abstract

To provide a gas barrier laminate, a packaging material, a packaging body and a packaged article, simultaneously realizing transparency and gas barrier properties under a high-temperature high-humidity environment.SOLUTION: A gas barrier laminate includes a base material 1, an inorganic vapor-deposited layer 2 containing an inorganic oxide and a coating layer 3 in this order. The coating layer contains a carboxyl group-containing polymer (a), a polyvalent metal-containing particle (b), a surfactant (c) and a silicon-containing compound (d). The silicon-containing compound (d) is at least one kind selected from a group consisting of a silane coupling agent having a specific structure, a hydrolyzate thereof, and a condensation product thereof. A mole ratio (dt / at) expressed by [a mole number (dt) of the silicon-containing compound (d) / a mole number (at) of a carboxyl group in the carboxyl group-containing polymer (a)] is 0.15 to 6.10%, inclusive. Film thickness of the coating layer is 230 to 600 nm, inclusive. However, the above (dt) is a mass obtained by converting the silicon-containing compound (d) to the silane coupling agent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a gas barrier laminate, a packaging material, a package, and a packaged article.

Background Art

[0002] When articles such as foods, pharmaceuticals, cosmetics, agricultural chemicals, and industrial products are stored for a long time, their quality may deteriorate due to oxygen. Therefore, films and sheets having oxygen gas barrier properties are used as packaging materials for these articles.

[0003] Conventionally, those having an aluminum foil as a gas barrier coating layer have been frequently used as such packaging materials. However, when using a packaging material containing aluminum foil, the contents cannot be visually recognized, and moreover, a metal detector cannot be used. Therefore, in particular, in the food and pharmaceutical fields, the development of a packaging material having excellent gas barrier properties and being transparent has been demanded.

[0004] Under such requirements, a gas barrier laminate provided with a layer made of polyvinylidene chloride (PVDC) by applying a coating solution containing PVDC on a substrate has been used. The layer made of PVDC is transparent and has gas barrier properties.

[0005] However, there is a concern about the generation of dioxins during incineration of PVDC. Therefore, a shift from PVDC to a non-chlorine-based material has been demanded. Under such requirements, for example, it has been proposed to use a polyvinyl alcohol (PVA)-based polymer instead of PVDC.

[0006] The layer made of a PVA-based polymer densifies due to hydrogen bonding of hydroxyl groups and exhibits high gas barrier properties in a low humidity atmosphere. However, the layer made of a PVA-based polymer has a problem that in a high humidity atmosphere, hydrogen bonds are loosened by moisture absorption and the gas barrier properties are greatly reduced. Therefore, a gas barrier laminate using a layer made of a PVA-based polymer as a gas barrier coating layer often cannot be used as a packaging material for foods containing a large amount of moisture, etc., and its applications have been limited to packaging materials for dried products, etc.

[0007] For the purpose of further improving the gas barrier properties, it has been proposed to add an inorganic layered compound to a PVA-based polymer (see, for example, Patent Document 1). However, even when an inorganic layered compound is added, since the water resistance of the PVA-based polymer itself is not improved, the problem that the gas barrier properties still decrease in a high humidity atmosphere 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-based polymer and a polymer capable of forming a crosslinked structure therewith to a substrate and performing heat treatment (see, for example, Patent Documents 2 and 3).

[0009] However, in order to obtain sufficient gas barrier properties by these techniques, it is necessary to perform heat treatment after coating the coating liquid at a high temperature, for example, 150°C or higher, to form a crosslinked structure. Such heat treatment causes severe deterioration of the substrate when the material of the substrate is a polyolefin such as polypropylene (OPP) or polyethylene (PE). Therefore, there is a demand for a gas barrier laminate that can be produced under milder conditions with the material of the substrate being restricted.

[0010] As a method for forming a gas barrier coating layer, a method has also been proposed in which a layer containing a polycarboxylic acid-based polymer such as polyacrylic acid is formed and this polycarboxylic acid-based polymer is ion-crosslinked with a polyvalent metal ion (see, for example, Patent Documents 4 to 6).

[0011] In this method, the high-temperature heat treatment performed by the methods described in Patent Documents 2 and 3 is unnecessary. Therefore, a polyolefin can be used as the base material. In addition, the obtained gas barrier coating layer is excellent in gas barrier properties even in a high-humidity atmosphere. Therefore, the gas barrier laminate including this gas barrier coating layer can also be used for applications that require heat sterilization treatment such as boiling or retorting.

[0012] However, when a polycarboxylic acid-based polymer and a polyvalent metal compound coexist in the coating solution, the polycarboxylic acid-based polymer and the polyvalent metal compound react in the coating solution and precipitation easily occurs. When precipitation occurs in the solution, a uniform film cannot be formed. Therefore, in this method, when forming the gas barrier coating layer, the layer containing the polycarboxylic acid-based polymer and the layer containing the polyvalent metal compound are formed separately, or an aqueous solution of a polyvalent metal salt is brought into contact with the layer containing the polycarboxylic acid-based polymer. Therefore, when this method is used, the number of steps increases in terms of making the gas barrier coating layer a two-layer structure.

[0013] A gas barrier film containing a polycarboxylic acid-based polymer and polyvalent metal compound particles in the same gas barrier coating layer is disclosed in Patent Document 7. Here, as a coating solution used for forming the gas barrier coating layer, it is proposed that the water content be 1000 ppm or less in a coating solution containing a polycarboxylic acid-based polymer, polyvalent metal compound particles, a surfactant, and an organic solvent. In this coating solution, since the water content is 1000 ppm or less, the reaction between the polycarboxylic acid-based polymer and the polyvalent metal compound is suppressed.

Prior Art Documents

Patent Documents

[0014]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Summary of the Invention

Problems to be Solved by the Invention

[0015] Patent Document 7 describes that the coating liquid disclosed therein can form a film having excellent gas barrier properties under high humidity conditions. However, the laminate formed by coating this coating liquid may peel between the gas barrier coating layer and the layer adjacent thereto, for example, the film substrate, in a more severe high temperature and high humidity environment, and there is a risk of a decrease in gas barrier properties.

[0016] When a silane coupling agent is added to the gas barrier coating layer to increase the laminate strength between the film substrate and the gas barrier coating layer, the transparency decreases. Thus, it is difficult to obtain a gas barrier laminate excellent in both transparency and gas barrier properties under high temperature and high humidity environments.

[0017] An object of the present invention is to provide a gas barrier laminate, a packaging material, a package, and a packaged article that achieve both transparency and a high level of gas barrier properties under high temperature and high humidity environments.

Means for Solving the Problems

[0018] According to a first aspect of the present invention, there is provided a gas barrier laminate comprising, in this order, a substrate, an inorganic vapor deposition layer containing an inorganic oxide, and a coating layer, the coating layer comprising a carboxy group-containing polymer (a), a polyvalent metal-containing particle (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, the number of moles of carboxy groups contained in the carboxy group-containing polymer (a) being (a t The number of moles of the silicon-containing compound (d) relative to the t ) molar ratio (d t ) / (a t ) is 0.15% or more and 6.10% or less, and the coating layer has a thickness of 230 nm or more and 600 nm or less. t ) / (a t ) in (d t ) is the mass of the silicon-containing compound (d) converted into a 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.

[0019] In an embodiment of the present invention, the carboxy group-containing polymer (a) may contain at least a constituent 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.

[0020] In the embodiment of the present invention, the polyvalent metal constituting the polyvalent metal-containing particles (b) may be a divalent metal.

[0021] Further, in an embodiment of the present invention, the gas barrier laminate may further include an anchor coat layer between the base material and the inorganic vapor deposition layer.

[0022] According to a second aspect of the present invention, there is provided a packaging material including the gas barrier laminate.

[0023] According to a third aspect of the present invention, there is provided a package including the packaging material.

[0024] According to a third aspect of the present invention, there is provided a packaged article including the package and the contents contained in the package.

Advantages of the Invention

[0025] According to the present invention, it is possible to provide a gas barrier laminate, a packaging material, a package, and a packaged article that achieve both transparency and a high level of gas barrier properties in a high-temperature and high-humidity environment.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0027] Hereinafter, this embodiment will be described with reference to the drawings. Note that elements having the same or similar functions are denoted by the same reference numerals, and redundant descriptions are omitted.

[0028] FIG. 1 is a cross-sectional view schematically showing a gas barrier laminate according to a first embodiment of the present invention. The gas barrier laminate 10 shown in FIG. 1 includes a base material 1, an inorganic vapor deposition layer 2 containing an inorganic oxide, and a coating layer 3.

[0029] The coating layer 3 contains a carboxy group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), and a silicon-containing compound (d), which will be described in detail below. The carboxy group-containing polymer (a) is ionically crosslinked with polyvalent metal ions derived from the polyvalent metal-containing particles (b), and exhibits excellent gas barrier properties even in a high-humidity atmosphere. And, since the coating layer 3 contains the silicon-containing compound (d), the gas barrier properties are further enhanced. On the other hand, by adjusting the blending amount of the silicon-containing compound (d) to a range satisfying 0.15% or more and 6.10% or less in the molar ratio represented by [(the number of moles of the silicon-containing compound (d t ) / (the number of moles of carboxy groups contained in the carboxy group-containing polymer (a t ))], and setting the film thickness of the coating layer 3 to 230 nm or more and 600 nm or less, the transparency is improved. Further, since the gas barrier laminate 10 includes an inorganic vapor deposition layer 2 between the coating layer 3 and the base material 1, the gas barrier properties are further improved, enabling both transparency and high gas barrier properties.

[0030] <Coating layer> 〔Carboxy group-containing polymer (a)〕 The carboxy group-containing polymer (a) contained in the coating layer 3 is a polymer having two or more carboxy groups in the molecule, and may be referred to as a "polycarboxylic acid-based polymer" hereinafter. As described above, the carboxy group-containing polymer (a) forms an ionic crosslink with metal ions derived from the polyvalent metal-containing particles (b) described later in the coating layer 3, and exhibits excellent gas barrier properties. Examples of the carboxy group-containing polymer (a) include homopolymers of carboxy group-containing unsaturated monomers, copolymers of two or more carboxy group-containing unsaturated monomers, copolymers of carboxy group-containing unsaturated monomers and other polymerizable monomers, and polysaccharides containing carboxy groups in the molecule (also referred to as "carboxy group-containing polysaccharides" or "acidic polysaccharides").

[0031] 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 part of the carboxy group may be neutralized with an alkali. In this case, the degree of neutralization is preferably 20% or less.

[0032] Here, the "degree of neutralization" is a value obtained by the following method. That is, the carboxy group can be partially neutralized by adding an alkali (f t ) to the carboxy group-containing polymer (a). At this time, the ratio of the number of moles of the alkali (f) to the number of moles of the carboxy group (a t ) contained in the carboxy group-containing polymer (a) is the degree of neutralization. t ) is the degree of neutralization.

[0033] In addition, a graft polymer obtained by graft-polymerizing a carboxy group-containing unsaturated monomer onto a polymer containing no carboxy group such as polyolefin can also be used as the carboxy group-containing polymer (a). A polymer having a hydrolyzable ester group such as an alkoxycarbonyl group (for example, a methoxycarbonyl group) can be hydrolyzed and used as a polymer converted to a carboxy group.

[0034] As the carboxy group-containing unsaturated monomer, α,β-monoethylenically unsaturated carboxylic acid is preferable. Therefore, the carboxy group-containing polymer (a) includes a homopolymer of α,β-monoethylenically unsaturated carboxylic acid, a copolymer of two or more α,β-monoethylenically unsaturated carboxylic acids, and a copolymer of α,β-monoethylenically unsaturated carboxylic acid and other polymerizable monomers. As the other polymerizable monomer, ethylenically unsaturated monomers are typical.

[0035] Examples of the α,β-monoethylenically unsaturated carboxylic acid 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 acid 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 preferable, 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 preferable.

[0036] Examples of other polymerizable monomers copolymerizable with the α,β-monoethylenically unsaturated carboxylic acid, particularly ethylenically unsaturated monomers, include ethylene; α-olefins such as propylene, 1-butene, 1-pentene, 1-hexene, and 1-octene; vinyl esters of saturated carboxylic acids such as vinyl acetate; alkyl acrylates such as methyl acrylate and ethyl acrylate; alkyl methacrylates 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 alkyl itaconates. These ethylenically unsaturated monomers can be used alone or in combination of two or more. Further, when the carboxy group-containing polymer is a copolymer of an α,β-monoethylenically unsaturated carboxylic acid and a vinyl ester of a saturated carboxylic acid such as vinyl acetate, a copolymer obtained by saponifying this copolymer to convert the vinyl ester unit of the saturated carboxylic acid into a vinyl alcohol unit can also be used.

[0037] Examples of the carboxy group-containing polysaccharide include acidic polysaccharides having a carboxy group in the molecule, such as alginic acid, carboxymethyl cellulose, and pectin. These acidic polysaccharides can be used alone or in combination of two or more. Further, the acidic polysaccharide can be used in combination with a (co)polymer of an α,β-monoethylenically unsaturated carboxylic acid.

[0038] When the carboxy group-containing polymer is a copolymer of an α,β-monoethylenically unsaturated carboxylic acid and other ethylenically unsaturated monomers, from the viewpoints of the gas barrier property, heat-resistant water resistance, and water vapor resistance of the resulting film, in the copolymer, the proportion of the number of moles of the α,β-monoethylenically unsaturated carboxylic acid monomer in the total number of moles of those monomers is preferably 60 mol% or more, more preferably 80 mol% or more, and particularly preferably 90 mol% or more.

[0039] The carboxy group-containing polymer (a) is preferably a homopolymer or copolymer obtained by polymerizing only an α,β-monoethylenically unsaturated carboxylic acid in that a film excellent in gas barrier property, moisture resistance, water resistance, heat-resistant water resistance, and water vapor resistance and excellent in gas barrier property under high humidity conditions can be easily obtained. When the carboxy group-containing polymer (a) is a (co)polymer composed only of an α,β-monoethylenically unsaturated carboxylic acid, preferable specific examples thereof are homopolymers, copolymers, and mixtures of two or more thereof obtained by polymerizing 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 preferable.

[0040] As the carboxy group-containing polymer (a), polyacrylic acid, polymethacrylic acid, polymaleic acid, and a mixture of two or more of these are particularly preferable. As the acidic polysaccharide, alginic acid is preferable. Among these, polyacrylic acid is particularly preferable in that it is relatively easy to obtain and a film excellent in various physical properties is easily obtained.

[0041] The number average molecular weight of the carboxy group-containing polymer (a) is not particularly limited, but from the viewpoints of film-forming property and film physical properties, it 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 still more preferably in the range of 10,000 to 500,000.

[0042] Here, the "number average molecular weight" is a value obtained by measurement by gel permeation chromatography (GPC). In GPC measurement, generally, the number average molecular weight of the polymer is measured in terms of standard polystyrene.

[0043] [Polyvalent metal-containing particles (b)] The polyvalent metal-containing particles (b) contained in the coating layer 3 are preferably particles containing one or more polyvalent metals having a valence of 2 or more of metal ions. The polyvalent metal-containing particles (b) may be particles composed of a polyvalent metal having a valence of 2 or more of metal ions, may be particles composed of a compound of a polyvalent metal having a valence of 2 or more of metal ions, or may be a mixture thereof.

[0044] Specific examples of the polyvalent metal include metals in Group 2A of the short-period type periodic table such as beryllium, magnesium, and calcium; transition metals such as titanium, zirconium, chromium, manganese, iron, cobalt, nickel, copper, and zinc; and aluminum, but are not limited thereto.

[0045] The polyvalent metal is preferably a divalent metal. Further, the polyvalent metal preferably forms a compound.

[0046] Specific examples of the polyvalent metal compound include, but are not limited to, oxides, hydroxides, carbonates, organic acid salts, and inorganic acid salts of polyvalent metals. Examples of the organic acid salts include, but are not limited to, acetates, oxalates, citrates, lactates, phosphates, phosphites, hypophosphites, stearates, and monoethylenically unsaturated carboxylates. Examples of the inorganic acid salts include, but are not limited to, chlorides, sulfates, and nitrates. The alkyl alkoxides of polyvalent metals can also be used as the polyvalent metal compound. These polyvalent metal compounds can be used alone or in combination of two or more thereof.

[0047] Among the polyvalent metal compounds, from the viewpoint of the gas barrier property of the gas barrier laminate 10, compounds of beryllium, magnesium, calcium, copper, cobalt, nickel, zinc, aluminum, and zirconium are preferable, and compounds of divalent metals such as beryllium, magnesium, calcium, copper, zinc, cobalt, and nickel are more preferable.

[0048] Preferable 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.

[0049] The polyvalent metal or polyvalent metal compound is used as particles. As the polyvalent metal particles (b), from the viewpoints of the dispersion stability of a coating solution (hereinafter referred to as "coating solution for forming the coating layer" or simply "coating solution") used for forming the coating layer 3 and the gas barrier property of the gas barrier laminate 10, those having an average particle diameter in the range of 10 nm to 10 μm (or 10,000 nm) as the average particle diameter in the coating solution are preferably used. The polyvalent metal particles (b) more preferably have an average particle diameter in the range of 12 nm to 1 μm (or 1,000 nm), still more preferably in the range of 15 nm to 500 nm, and particularly preferably in the range of 15 nm to 50 nm.

[0050] If the average particle diameter of the polyvalent metal-containing particles (b) is too large, the uniformity of the film thickness of the coating layer 3, the surface flatness, the ionic crosslinking reactivity with the carboxy group-containing polymer (a), etc. tend to be insufficient. If the average particle diameter of the polyvalent metal-containing particles (b) is too small, there is a risk that the ionic crosslinking reaction with the carboxy group-containing polymer (a) may proceed prematurely. Also, if the average particle diameter of the polyvalent metal-containing particles (b) is too small, it may be difficult to uniformly disperse them in the coating solution.

[0051] When the sample is a dried solid, the average particle diameter of the polyvalent metal-containing particles (b) can be measured by performing measurement and counting using a scanning electron microscope or a transmission electron microscope. The average particle diameter of the polyvalent metal-containing particles (b) in the coating solution can be measured by a light scattering method [Reference: "Fine Particle Engineering System", Volume I, pages 362 - 365, Fujitecno System (2001)].

[0052] The polyvalent metal-containing particles in the coating solution exist as primary particles, secondary particles, or a mixture thereof, but in many cases, they are presumed to exist as secondary particles in terms of the average particle diameter.

[0053] 〔Surfactant (c)〕 The coating layer 3 contains a surfactant (c) in order to enhance the dispersibility of the polyvalent metal-containing particles (b). 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. In the coating layer 3, any surfactant may be used.

[0054] Examples of anionic surfactants include carboxylic acid type, sulfonic acid type, sulfuric acid ester type, and phosphoric acid ester type. Examples of carboxylic acid type anionic surfactants include aliphatic monocarboxylate salts, polyoxyethylene alkyl ether carboxylate salts, N-acyl sarcosinate salts, and N-acyl glutamate salts. Examples of sulfonic acid type anionic surfactants include dialkyl sulfosuccinate salts, alkane sulfonate salts, alpha olefin sulfonate salts, linear alkylbenzene sulfonate salts, alkyl (branched chain) benzene sulfonate salts, naphthalene sulfonate-formaldehyde condensates, alkyl naphthalene sulfonate salts, and N-methyl-N-acyl taurate salts. Examples of sulfuric acid ester type anionic surfactants include alkyl sulfate salts, polyoxyethylene alkyl ether sulfate salts, and oil and fat sulfate ester salts. Examples of phosphoric acid ester type anionic surfactants include alkyl phosphate salts, polyoxyethylene alkyl ether phosphate salts, and polyoxyethylene alkyl phenyl ether phosphate salts.

[0055] Examples of cationic surfactants (c) include alkylamine salt type and quaternary ammonium salt type. Examples of alkylamine salt type cationic surfactants include monoalkylamine salts, dialkylamine salts, and trialkylamine salts. Examples of quaternary ammonium salt type cationic surfactants include alkyltrimethylammonium halide salts (chloride, bromide, or iodide) and alkylbenzalkonium chloride.

[0056] Examples of amphoteric surfactants include carboxybetaine type, derivatives of 2-alkylimidazoline, glycine type, and amine oxide type. Examples of carboxybetaine type amphoteric surfactants include alkyl betaine and fatty acid amide propyl betaine. Examples of derivatives of 2-alkylimidazoline 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.

[0057] Examples of nonionic surfactants include ester type, ether type, ester-ether type, and alkanolamide type. Examples of ester type nonionic surfactants include glycerin fatty acid ester, sorbitan fatty acid ester, and sucrose fatty acid ester. Examples of ether type nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, and polyoxyethylene polyoxypropylene glycol. Examples of ester-ether type nonionic surfactants include fatty acid polyethylene glycol and fatty acid polyoxyethylene sorbitan. Examples of alkanolamide type nonionic surfactants include fatty acid alkanolamide.

[0058] Surfactants having a polymer backbone such as a styrene-acrylic acid copolymer can also be used.

[0059] Among these surfactants, anionic surfactants such as phosphate esters and surfactants having a polymer backbone such as a styrene-acrylic acid copolymer are preferred.

[0060] [Silicon-containing compound (d)] The coating layer 3 contains a silicon-containing compound (d) in order to increase the peel strength. The silicon-containing compound (d) 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 hydrolyzates, and their condensates. Si(OR1)3Z1…(1) Si(R2)(OR3)2Z2…(2) In the general formula (1), R1 is an alkyl group having 1 to 6 carbon atoms which may be the same or different, and Z1 is a group containing an epoxy group. In the general formula (2), R2 is a methyl group, R3 is an alkyl group having 1 to 6 carbon atoms which may be the same or different, and Z2 is a group containing an epoxy group.

[0061] Silane coupling agents easily undergo hydrolysis and also easily undergo a condensation reaction in the presence of an acid or an alkali. Therefore, in the coating layer 3, it is rare for the silicon-containing compound (d) to exist only in the form of the silane coupling agent represented by the 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 layer 3, the silicon-containing compound (d) usually coexists as a mixture of at least one of the silane coupling agent represented by the general formula (1) and the silane coupling agent represented by the general formula (2), its hydrolyzate, and its condensate.

[0062] Each of R1 and R3 in the general formulas (1) and (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 and Z2 may be a group containing an epoxy group, and may be, for example, an organic group having a glycidyloxy group.

[0063] Specific examples of the silane coupling agent represented by the general formula (1) or (2) include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane. Among them, 3-glycidoxypropylmethyldimethoxysilane and 3-glycidoxypropyltrimethoxysilane are preferred. As the silane coupling agent, one kind or two or more kinds can be used.

[0064] The hydrolyzate of the silane coupling agent represented by the general formula (1) or (2) may be a partial hydrolyzate, a complete hydrolyzate, or a mixture thereof.

[0065] The condensate that the coating layer 3 may contain as at least a part of the silicon-containing compound (d) includes a hydrolysis condensate of the silane coupling agent represented by the general formula (1), a hydrolysis condensate of the silane coupling agent represented by the general formula (2), and a condensate of a hydrolyzate of the silane coupling agent represented by the general formula (1) and a hydrolyzate of the silane coupling agent represented by the general formula (2), and there are two or more of them. These hydrolysis condensates are produced by the following reaction. That is, first, the silane coupling agent is hydrolyzed. As a result, one or more of the alkoxy groups contained in the molecule of the silane coupling agent are substituted by hydroxyl groups to form a hydrolyzate. Subsequently, by condensing these hydrolyzates, a compound in which silicon atoms (Si) are bonded through oxygen is formed. By repeating this condensation, a hydrolysis condensate is obtained.

[0066] 〔Composition〕 The coating layer 3 preferably contains the carboxyl group-containing polymer (a) and the polyvalent metal-containing particles (b) in the following mixing ratio. That is, the ratio of the product of the number of moles (b t ) of the polyvalent metal contained in the polyvalent metal-containing particles (b) and the valence number to the number of moles (a t ) of the carboxyl group contained in the carboxyl group-containing polymer (a) ((b t) / (a t )) (hereinafter also referred to as the equivalent ratio) is preferably 0.6 or more. This ratio is more preferably 0.8 or more, and particularly preferably 1.0 or more. The upper limit of this ratio is usually 10.0, preferably 2.0. If this ratio is made too small, various properties such as the gas barrier property, heat water resistance, and water vapor resistance of the gas barrier laminate 10 tend to deteriorate.

[0067] The above equivalent ratio can be determined, for example, as follows. Taking the case where the carboxy group-containing polymer (a) is polyacrylic acid and the polyvalent metal compound particles (b) are magnesium oxide as an example for explanation.

[0068] Polyacrylic acid has a monomer unit molecular weight of 72 and has one carboxy group per molecule of monomer. Therefore, the amount of carboxy groups in 100 g of polyacrylic acid is 1.39 mol. That the equivalent ratio in the coating liquid containing 100 g of polyacrylic acid is 1.0 means that the coating layer 3 contains an amount of magnesium oxide that neutralizes 1.39 mol of carboxy groups. Therefore, to make the above equivalent ratio in the coating layer 3 containing 100 g of polyacrylic acid 0.6, an amount of magnesium oxide that neutralizes 0.834 mol of carboxy groups may be blended into this coating layer 3. Here, the valence of magnesium is divalent and the molecular weight of magnesium oxide is 40. Therefore, to make the above equivalent ratio in the coating layer 3 containing 100 g of polyacrylic acid 0.6, 16.68 g (0.417 mol) of magnesium oxide may be blended into this coating layer 3.

[0069] The surfactant (c) is used in an amount sufficient for the polyvalent metal-containing particles to be stably dispersed in the coating liquid. Therefore, when explaining its blending amount as the concentration in the coating liquid for forming the coating layer, in the coating liquid, it 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.

[0070] If the surfactant (c) is not added, it becomes difficult to disperse the polyvalent metal-containing particles (b) in the coating liquid so that their average particle diameter becomes sufficiently small. As a result, it becomes difficult to obtain a coating liquid in which the polyvalent metal-containing particles (b) are uniformly dispersed. In that case, it becomes difficult to obtain a coating layer 3 having a uniform thickness in the coating layer 3 obtained by applying the coating liquid on the inorganic vapor deposition layer 2 and drying it.

[0071] In order to achieve both high gas barrier properties and transparency in the gas barrier laminate 10, the coating layer 3 contains a silicon-containing compound (d) in an amount of 1 mole of the carboxy group contained in the carboxy group-containing polymer (a) (a t The mole number of silicon-containing compound (d) relative to t ) molar ratio (d t ) / (a t The 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.

[0072] The amount of silicon-containing compound (d) added is too small, and the molar ratio (d t ) / (a t ) is less than 0.15%, the peel strength of the gas barrier laminate 10 decreases, and therefore careful handling is required to prevent delamination, which can lead to reduced productivity.

[0073] The number of moles of carboxy groups contained in the carboxy group-containing polymer (a) (a t The mole number of silicon-containing compound (d) relative to t ) molar ratio (d t ) / (a t From the above viewpoint, the content of Cr is preferably 0.3% or more, more preferably 0.46% or more, and particularly preferably 0.61% or more.

[0074] On the other hand, the amount of silicon-containing compound (d) added is too large, and the above molar ratio (d t) / (a t ) If it is higher than 6.10%, the transparency of the gas barrier laminate 10 will decrease. Also, the silicon-containing compound (d) does not have gas barrier properties. Therefore, when the molar ratio (d t ) / (a t ) is higher than 6.10%, not only will the transparency of the laminate decrease, but the gas barrier properties will also decrease.

[0075] The molar ratio (d t ) of the number of moles of the silicon-containing compound (d) to the number of moles of the carboxyl group (a t ) contained in the carboxyl group-containing polymer (a) t ) / (a t ) is preferably 4.57% or less, more preferably 3.66% or less, and particularly preferably 2.13% or less from the above viewpoints.

[0076] The film thickness of the coating layer 3 is 230 nm or more and 600 nm or less from the viewpoint of achieving both transparency and gas barrier properties. Here, the film thickness of the coating layer 3 is specifically the film thickness measured by the film thickness measurement method of the coating layer described later. The film thickness of the coating layer 3 is preferably 250 nm or more and 500 nm or less, and more preferably 300 nm or more and 450 nm or less.

[0077] <Inorganic vapor deposition layer> The gas barrier laminate 10 according to the present embodiment includes an inorganic vapor deposition layer 2 between the base material 1 and the coating layer 3. Thereby, the gas barrier properties of the gas barrier laminate 10 including the coating layer 3 can be further enhanced, and it becomes possible to achieve both transparency and high gas barrier properties.

[0078] The inorganic vapor deposition layer 2 contains an inorganic oxide. Examples of the inorganic oxide include aluminum oxide, silicon oxide, magnesium oxide, tin oxide, etc. Among these, from the viewpoint of achieving both transparency and gas barrier properties, aluminum oxide, silicon oxide, magnesium oxide, or a mixture of any two or more of them is preferable.

[0079] The thickness of the inorganic vapor deposition layer 2 may be, for example, in the range of 5 to 100 nm, or may be in the range of 10 to 50 nm. It is preferable that the thickness of the inorganic vapor deposition layer 2 is 5 nm or more from the viewpoint of forming a uniform thin film. When the thin film as the gas barrier material is uniform, the functions required for the gas barrier material can be sufficiently achieved. It is preferable that the thickness of the inorganic vapor deposition layer 2 is 100 nm or less from the viewpoint of the flexibility of the thin film. If the flexibility of the gas barrier material is poor, there is a risk of cracking due to external factors such as bending and pulling.

[0080] <Base material> There is no particular limitation on the base material 1 included in the gas barrier laminate 10 according to the present embodiment, and various types can be used. The material constituting the base material 1 is not particularly limited, and various types can be used, such as plastic or paper.

[0081] The base material 1 may be a single layer made of a single material or a multilayer made of a plurality of materials. Examples of the multilayer base material include a film made of plastic laminated on paper.

[0082] Among the above, as the material constituting the base material 1, plastic is preferable because it can be formed into various shapes and the applications can be further expanded by imparting gas barrier properties.

[0083] The plastic is not particularly limited, and examples thereof include 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)acrylate; polyacrylonitrile; polyvinyl acetate; ethylene-vinyl acetate copolymer; ethylene-vinyl alcohol copolymer; polycarbonate; polyarylate; regenerated cellulose; polyimide; polyetherimide; polysulfone; polyethersulfone; polyetherketone; and ionomer resin.

[0084] When the gas barrier laminate is used as a food packaging material, the base material 1 is preferably made of polyethylene, polypropylene, polyethylene terephthalate, nylon-6 or nylon-66.

[0085] As the plastic constituting the base material 1, one kind may be used alone, or two or more kinds may be blended and used.

[0086] Additives may be compounded in the plastic. As the additives, known additives such as pigments, antioxidants, antistatic agents, ultraviolet absorbers, and lubricants can be appropriately selected according to the use. As the additives, one kind may be used alone, or two or more kinds may be used in combination.

[0087] The form of the base material 1 is not particularly limited, and examples thereof include films, sheets, cups, trays, tubes, and bottles. Among these, a film is preferred.

[0088] When the base material 1 is a film, this film may be a stretched film or an unstretched film.

[0089] Although there is no particular limitation on the thickness of the film, from the viewpoints of the mechanical strength and processability of the resulting gas barrier laminate, it is preferably in the range of 1 to 200 μm, and more preferably in the range of 5 to 100 μm.

[0090] On the surface of the base material 1, in order to be able to apply the coating liquid without being repelled by the base material, plasma treatment, corona treatment, ozone treatment, flame treatment, or radical activation treatment by ultraviolet rays (UV) or electron beams may be performed. The treatment method is appropriately selected according to the type of the base material.

[0091] 〔Other Layers〕 The gas barrier laminate according to the present embodiment may further include one or more other layers other than the base material 1, the inorganic vapor deposition layer 2, and the coating layer 3, if necessary.

[0092] For example, the gas barrier laminate according to the present embodiment may include only the above-described coating layer 3 as the gas barrier coat layer, but may further include one or more other layers in addition to the coating layer 3. For example, a layer made of an inorganic compound such as aluminum oxide, silicon oxide, and aluminum may be formed on the surface of the base material by a sputtering method or an ion plating method or the like.

[0093] Further, the gas barrier laminate according to the present embodiment has an anchor coat layer between the base material 1 and the inorganic vapor deposition layer 2, or between the inorganic vapor deposition layer 2 and the coating layer 3, for the purpose of enhancing the adhesion between layers or enabling the coating liquid for forming the coating layer to be applied without being repelled by the inorganic vapor deposition layer.

[0094] FIG. 2 is a cross-sectional view schematically showing a gas barrier laminate according to the second embodiment of the present invention. The gas barrier laminate 20 shown in FIG. 2 further includes an anchor coat layer 4 between the base material 1 and the inorganic vapor deposition layer 2 with respect to the gas barrier laminate 10 according to the first embodiment described above.

[0095] The anchor coat layer 4 can be formed by a conventional method using a known anchor coat liquid. Examples of the anchor coat liquid include those containing resins such as polyurethane resin, acrylic resin, melamine resin, polyester resin, phenol resin, amino resin, and fluororesin.

[0096] In addition to the resin, the anchor coat liquid may further contain an isocyanate compound for the purpose of enhancing adhesion and heat water resistance. The isocyanate compound may be any one having one or more isocyanate groups in the molecule, and examples thereof include hexamethylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, and tolylene diisocyanate. The anchor coat liquid may further contain a liquid medium for dissolving or dispersing the resin and the isocyanate compound.

[0097] The thickness of the anchor coat layer 4 is not particularly limited. The thickness of the anchor coat layer 4 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. When the film thickness is less than 0.01 μm, since it is very thin, the performance as an anchor coat layer may not be fully exhibited. On the other hand, it is preferable that the film thickness is 2 μm or less from the viewpoint of flexibility. When the flexibility decreases, there is a risk of cracking in the anchor coat layer due to external factors.

[0098] The gas barrier laminate according to the present embodiment may further include another layer laminated via an adhesive on the coating layer 3, or on the surface of the base material 1 or the inorganic vapor deposition layer 2, if necessary, or may further include another layer formed by extrusion lamination of an adhesive resin.

[0099] The other layer to be laminated can be appropriately selected according to purposes such as imparting strength, imparting sealability, imparting easy peelability during sealing, imparting designability, imparting light shielding property, and imparting moisture resistance, and is not particularly limited. For example, those made of the same material as the plastic described above for the base material can be mentioned. In addition, paper, aluminum foil, etc. may be used.

[0100] 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, still more preferably in the range of 5 to 200 μm, and particularly preferably in the range of 5 to 150 μm. The other layer to be laminated may be one kind or two or more kinds.

[0101] The gas barrier laminate according to the present embodiment may further include a printing layer, if necessary. The printing layer may be formed on a coating layer provided on a base material, or may be formed on the surface of a base material without a coating layer. Further, when another layer is laminated, it may be formed on the other layer to be laminated.

[0102] 〔Method for manufacturing gas barrier laminate〕 The gas barrier laminate according to the present embodiment can be manufactured by a manufacturing method including a step of forming an inorganic vapor deposition layer and a step of forming a coating layer using a coating liquid for forming a coating layer shown below. This manufacturing method can further include a step of forming other layers such as an anchor coat layer and / or a step of forming a printing layer, etc., if necessary.

[0103] As an example of the manufacturing method of the gas barrier laminate according to the present embodiment, the manufacturing method of the gas barrier laminate 20 shown in FIG. 2 will be described below.

[0104] In the manufacturing method of the gas barrier laminate 20, the anchor coat layer 4 is formed on the base material 1. The anchor coat layer 4 can be formed by applying the above-described anchor coat liquid on the base material 1 and drying the formed coating film. The coating method of the anchor coat liquid is not particularly limited, and it can be carried out using well-known printing methods such as offset printing method, gravure printing method, silk screen printing method, etc., or well-known coating methods such as roll coating, knife edge coating, gravure coating, etc. By drying the formed coating film, the removal of the solvent and curing proceed, and the anchor coat layer 4 is formed.

[0105] In the method for manufacturing the gas barrier laminate 20, the inorganic vapor deposition layer 2 is formed on the anchor coat layer 4. As the method for forming the inorganic vapor deposition layer 2, various methods are known, such as vacuum evaporation, sputtering, ion plating, chemical vapor deposition (CVD), etc., and any method may be used, but it is common to form it by the vacuum evaporation method. As the heating means of the vacuum evaporation apparatus by the vacuum evaporation method, an electron beam heating method, a resistance heating method, an induction heating method, etc. may be mentioned, and any of them may be used. In addition, in order to improve the adhesion of the inorganic vapor deposition layer 2 to the anchor coat layer 4 and the denseness of the inorganic vapor deposition layer 2, it is also possible to use a plasma assist method or an ion beam assist method. In addition, in order to increase the transparency of the inorganic vapor deposition layer 2, reactive evaporation such as blowing in oxygen gas during evaporation may be performed.

[0106] In the method for manufacturing 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 a coating liquid for forming a coating layer prepared by the method described below on the inorganic vapor deposition layer 2 and drying the formed coating film.

[0107] · Method for preparing the coating liquid for forming the coating layer In the coating liquid for forming the coating layer, an organic solvent (e) is used as a solvent or a dispersion medium. That is, this coating liquid 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, in which the polyvalent metal-containing particles (b) are dispersed.

[0108] The organic solvent (e) is used in an amount sufficient for the carboxyl group-containing polymer (a) to dissolve uniformly and the polyvalent metal-containing particles to disperse uniformly. Therefore, as the organic solvent, one that can dissolve the carboxyl group-containing polymer but does not substantially dissolve the polyvalent metal compound and can disperse it in the form of particles is used.

[0109] In addition, as the organic solvent (e), generally, a polar organic solvent that dissolves the carboxy group-containing polymer (a) is used. However, an organic solvent having no polar group (hetero atom or atomic group having a hetero atom) may be used in combination with the polar organic solvent.

[0110] Examples of the preferably usable organic solvents (e) include alcohols such as methanol, ethanol, isopropanol, n-propanol, and n-butanol; polar organic solvents such as dimethyl sulfoxide, N,N-dimethylacetamide, N,N-dimethylformamide, N-methyl-2-pyrrolidone, tetramethylurea, hexamethylphosphoric triamide, and γ-butyrolactone.

[0111] In addition to the above polar organic solvents, 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 appropriately used as the organic solvent (e). Hydrocarbons such as benzene having no polar group are generally used in combination with a polar organic solvent.

[0112] The above coating liquid may contain only the organic solvent (e) as a solvent or dispersion medium, or may further contain water. By containing water, the solubility of the carboxy group-containing polymer (a) 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 in terms of mass fraction.

[0113] The water content of this coating liquid is preferably 50,000 ppm or less, more preferably 10,000 ppm or less, and still more preferably 5,000 ppm or less in terms of mass fraction.

[0114] To prepare a coating solution for forming a coating layer, on the one hand, after uniformly dissolving a carboxyl group-containing polymer (a) in an organic solvent (e), a silicon-containing compound (d) is added thereto to prepare a carboxyl group-containing polymer solution.

[0115] On the other hand, polyvalent metal-containing particles (b), a surfactant (c), and an organic solvent (e) are mixed, and if necessary, a dispersion treatment is performed to prepare a dispersion. The dispersion treatment is performed so that the average particle diameter of the polyvalent metal-containing particles (b) becomes a predetermined value. When the average particle diameter of the polyvalent metal-containing particles (b) in the mixed solution before the dispersion treatment is 10 μm or less, the dispersion treatment may not be performed, but even in that case, it is preferable to perform the dispersion treatment. By performing the dispersion treatment, the aggregation of the polyvalent metal-containing particles (b) is resolved, the coating solution is stabilized, and the transparency of the gas barrier laminate obtained by coating the coating solution is increased. Furthermore, when the coating solution is coated and the coating film is dried, crosslinking formation between the carboxyl group-containing polymer (a) and the polyvalent metal ions derived from the polyvalent metal-containing particles (b) easily proceeds, and a gas barrier laminate having good gas barrier properties is easily obtained.

[0116] Examples of the dispersion treatment method include a method using a high-speed stirrer, a homogenizer, a ball mill, or a bead mill. In particular, when dispersion is performed using a ball mill or a bead mill, dispersion can be performed with high efficiency, and therefore, a coating solution having a stable dispersion state can be obtained in a relatively short time. In this case, the diameter of the balls or beads is preferably small, and is preferably 0.1 to 1 mm.

[0117] By mixing the carboxyl group-containing polymer solution and the dispersion of the polyvalent metal-containing particles (b) prepared as described above, a coating solution can be produced. In the preparation method described above, the silicon-containing compound (d) was added to the carboxyl group-containing polymer solution in advance, but the silicon-containing compound (d) may not be added to the carboxyl group-containing polymer solution, and for example, the silicon-containing compound (d) may be mixed when the carboxyl group-containing polymer solution and the dispersion of the polyvalent metal-containing particles (b) are mixed.

[0118] In the above coating solution, it is preferable that the total concentration of components other than the above organic solvent (e) is in the range of preferably 0.1 to 60% by mass, more preferably 0.5 to 25% by mass, and particularly preferably 1 to 20% by mass in order to obtain a coating film and a coating layer with a desired film thickness with high workability.

[0119] In the above coating solution, various additives such as other polymers, thickeners, stabilizers, ultraviolet absorbers, antiblocking agents, softeners, inorganic layered compounds (for example, montmorillonite), and colorants (dyes, pigments) can be contained as necessary.

[0120] The coating method of the coating solution is not particularly limited, and examples thereof include coating using a reverse roll coater such as an air knife coater, a direct gravure coater, a gravure offset, an arc gravure coater, a top feed reverse coater, a bottom feed reverse coater, and a nozzle feed reverse coater, a 5-roll coater, a lip coater, a bar coater, a bar reverse coater, and a die coater.

[0121] The drying method of the coating film is not particularly limited, and examples thereof include a method by natural drying, a method of drying in an oven set at a predetermined temperature, and a method using a dryer attached to the coater, such as an arch dryer, a floating dryer, a drum dryer, or an infrared dryer.

[0122] The drying conditions can be appropriately selected depending on the drying method and the like. For example, in the 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.

[0123] During or after drying, it is presumed that the carboxy group-containing polymer (a) contained in the coating film reacts with the polyvalent metal-containing particles (b) to introduce an ionic cross-linked structure. In order to sufficiently advance the ionic cross-linking reaction, the dried film is preferably aged for about 1 second to 10 days under temperature conditions preferably in the range of 5 to 200 °C, more preferably 20 to 150 °C, in an atmosphere of relative humidity preferably in the range of 20% or more, more preferably 40 to 100%.

[0124] The gas barrier laminate thus obtained has an ionic cross-linking, and thus is excellent in moisture resistance, water resistance, hydrothermal resistance, and water vapor resistance. And this gas barrier laminate is excellent in gas barrier properties not only under low humidity conditions but also under high humidity conditions. This gas barrier laminate preferably has an oxygen permeability measured under the conditions of a temperature of 30 °C and a relative humidity of 70% in accordance with the method described in JIS K-7126 B method (isobaric method) and ASTM D3985 of 10 cm 3 / (m 2 ·day·MPa) or less.

[0125] <Packaging material, package, and packaged article> The packaging material according to this embodiment includes the above-described gas barrier laminate. This packaging material is used, for example, in the manufacture of a package for packaging an article.

[0126] The package according to this embodiment includes the above-described packaging material. This package may be composed of the above-described packaging material, or may include the above-described packaging material and other members. In the former case, the package is, for example, a bag formed from the above-described packaging material. In the latter case, the package is, for example, a container including the above-described packaging material as a lid and a bottomed cylindrical container body.

[0127] In this package, the above packaging material may be a molded article. As described above, this molded article may be a container such as a bag, or may be a part of a container such as a lid. Specific examples of the package or a part thereof include a bagged product, a pouch with a spout, a laminated tube, an infusion bag, a lid material for a container, and a paper container.

[0128] There is no particular limitation on the application of this package. This package can be used for packaging various articles.

[0129] The packaged article according to this embodiment includes the above package and the contents contained therein.

[0130] As described above, the above gas barrier laminate has excellent gas barrier properties and transparency. Therefore, the packaging material and the package including this gas barrier laminate are preferably used as a packaging material and a package for articles that are easily deteriorated by the influence of oxygen, water vapor, etc., particularly as a packaging material and a package for food. These packaging materials and packages can also be preferably used as a packaging material and a package for packaging industrial materials such as chemicals such as pesticides and pharmaceuticals, medical devices, machine parts, and precision materials.

[0131] When the above gas barrier laminate is subjected to heat sterilization treatment such as boiling treatment and retort treatment, the gas barrier properties and the interlayer adhesion do not deteriorate, but rather tend to increase. Therefore, these packaging materials and packages may be a packaging material for heat sterilization and a packaging body for heat sterilization, respectively.

[0132] The packaging material for heat sterilization and the packaging body for heat sterilization are used for packaging articles that are subjected to heat sterilization treatment after packaging. Examples of articles that are subjected to heat sterilization treatment after packaging include foods such as curry, stew, soup, sauce, and processed meat products.

[0133] Examples of the heat sterilization treatment include boiling treatment and retort treatment. Boiling treatment is a wet heat sterilization treatment for preserving foods and the like. In boiling treatment, although it depends on the contents, usually, a packaged article obtained by packaging the contents such as foods in the above-described packaging body is subjected to wet heat sterilization treatment at a temperature of 60 to 100°C for 10 to 120 minutes under atmospheric pressure. Boiling treatment is usually performed using a hot water tank. Boiling treatment includes a batch type in which a packaged article is immersed in a hot water tank at a constant temperature and taken out after a certain time, and a continuous type in which a packaged article is passed through a hot water tank in a tunnel type for sterilization.

[0134] Retort treatment is generally a treatment for preserving foods and the like by subjecting microorganisms such as molds, yeasts, and bacteria to pressure heating sterilization. In retort treatment, usually, a packaged article obtained by packaging food in the above-described packaging body is subjected to pressure sterilization heating treatment at a temperature of 105 to 140°C for 10 to 120 minutes under a pressure of 0.15 to 0.3 MPa. Retort apparatuses include a steam type using heating steam and a hot water type using pressurized superheated water, etc., and they are appropriately selected according to the sterilization conditions of foods and the like as the contents.

Example

[0135] Specific examples of the present invention are described below. <Preparation of Anchor Coat Liquid> In a diluting solvent (ethyl acetate), 5 parts by mass of an acrylic polyol was mixed with 1 part by mass of γ-isocyanatopropyltrimethoxysilane and stirred. Then, tolylene diisocyanate (TDI) as an isocyanate compound was added so that the amount of NCO groups was equal to the amount of OH groups of the acrylic polyol. The obtained mixed solution was diluted with the above diluting solvent to a concentration of 2% by mass to obtain an anchor coat liquid. As the acrylic polyol, GS-5756 manufactured by Mitsubishi Rayon Co., Ltd. was used.

[0136] <Preparation of Coating Liquid for Forming Coating Layer> (Coating Liquid 1) The carboxy group-containing polymer was dissolved by heating in 2-propanol. As the carboxy group-containing polymer, polyacrylic acid (PAA) (Jumimer (registered trademark) AC-10LP manufactured by Toagosei Co., Ltd., number average molecular weight 50,000) was used. 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 (Disparon (registered trademark) DA-375 manufactured by Enomoto Kasei Co., Ltd., solid content 100% by mass) was dissolved in 26.2 g of 2-propanol. Then, 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 thereto and stirred. The resulting liquid was dispersed for 1 hour using a planetary ball mill (P-7 manufactured by Fritsch). For this dispersion treatment, zirconia beads with a diameter of 0.2 mm were used. Thereafter, the beads were sieved from this liquid to obtain a dispersion liquid containing zinc oxide at a concentration of 30% by mass.

[0138] Next, 31.20 g of a polyacrylic acid (PAA) solution, 5.79 g of a zinc oxide dispersion liquid, 0.08 g of a silane coupling agent (SC agent) (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd., 3-glycidoxypropyltrimethoxysilane) as a silicon-containing compound, and 23.57 g of 2-propanol were mixed to prepare Coating Liquid 1. In this Coating Liquid 1, the molar ratio ((d t ) / (a t )) of the number of moles (d t ) of the silicon-containing compound (d) to the number of moles (a t ) of the carboxy group contained in the carboxy group-containing polymer (a) was 0.78%.

[0139] (Coating Liquid 2) Coating Liquid 2 was prepared in the same manner as described above for Coating Liquid 1, except that the addition amount of the above silicon-containing compound was changed to 0.164 g. In this Coating Liquid 2, the molar ratio ((d t ) / (a t )) of the number of moles (dt ) / (a t )) was 1.60%.

[0140] (Coating liquid 3) Coating liquid 3 was prepared in the same manner as described above for coating liquid 1, except that the addition amount of the silicon-containing compound was changed to 0.499 g. In this coating liquid 2, the molar ratio of the number of moles of the silicon-containing compound (d t ) to the number of moles of the carboxyl group in the carboxyl group-containing polymer (a) (a t ) ((d t ) / (a t )) was 4.87%.

[0141] (Coating liquid 4) Coating liquid 4 was prepared in the same manner as described above for coating liquid 1, except that the addition amount of the silicon-containing compound was changed to 0.655 g. In this coating liquid 2, the molar ratio of the number of moles of the silicon-containing compound (d t ) to the number of moles of the carboxyl group in the carboxyl group-containing polymer (a) (a t ) ((d t ) / (a t )) was 6.40%.

[0142] (Coating liquid 5) Coating liquid 5 was prepared in the same manner as described above for coating liquid 1, except that no silicon-containing compound was added. In this coating liquid 5, the molar ratio of the number of moles of the silicon-containing compound (d t ) to the number of moles of the carboxyl group in the carboxyl group-containing polymer (a) (a t ) ((d t ) / (a t )) was 0%.

[0143] (Manufacture of gas barrier laminate) [Example 1] On one side of a biaxially oriented polypropylene film (manufactured by Mitsui Chemicals Toagosei Co., Ltd., trade name: ME-1, thickness 20 μm), Anchor Coat Liquid 1 was applied using a bar coater so that the thickness after drying would be 0.2 μm, and dried at 150°C for 1 minute to form an anchor coat layer.

[0144] On this anchor coat layer, silicon was evaporated using a vacuum deposition apparatus with an electron beam heating method, and oxygen gas was introduced there to deposit silicon oxide to form an inorganic deposited layer with a thickness of 20 nm. Coating Liquid 1 was applied onto this inorganic deposited 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 film thickness of 500 nm. The laminate 1 was obtained as described above. The film thickness of the coating layer was measured by the method described later.

[0145] [Example 2] A laminate 2 was obtained by the same method as described above for the laminate 1 of Example 1, except that the coating amount of Coating Liquid 1 was changed to change the film thickness of the coating layer.

[0146] [Example 3] A laminate 3 was obtained by the same method as described above for the laminate 1 of Example 1, except that the silicon oxide of the inorganic deposited layer was changed to aluminum oxide, and the coating amount of Coating Liquid 1 was changed to change the film thickness of the coating layer.

[0147] [Example 4] A laminate 4 was obtained by the same method as described above for the laminate 1 of Example 1, except that Coating Liquid 1 was changed to Coating Liquid 2, and the coating amount of the coating liquid was changed to change the film thickness of the coating layer.

[0148] [Example 5] A laminate 5 was obtained by the same method as described above for the laminate 1 of Example 1, except that Coating Liquid 1 was changed to Coating Liquid 3, and the coating amount of the coating liquid was changed to change the film thickness of the coating layer.

[0149] [Comparative Example 1] A laminate 1C was obtained in the same manner as described above for the laminate 1 of Example 1, except that an inorganic vapor deposition layer was not formed and the film thickness of the coating layer was changed by varying the coating amount of Coating Liquid 1.

[0150] [Comparative Example 2] A laminate 2C was obtained in the same manner as described above for the laminate 1 of Example 1, except that the film thickness of the coating layer was changed by varying the coating amount of Coating Liquid 1.

[0151] [Comparative Example 3] A laminate 3C was obtained in the same manner as described above for the laminate 4 of Example 4, except that an inorganic vapor deposition layer was not formed and the film thickness of the coating layer was changed by varying the coating amount of Coating Liquid 2.

[0152] [Comparative Example 4] A laminate 4C was obtained in the same manner as described above for the laminate 5 of Example 5, except that an inorganic vapor deposition layer was not formed.

[0153] [Comparative Example 5] A laminate 5C was obtained in the same manner as described above for the laminate 1 of Example 1, except that an inorganic vapor deposition layer was not formed and Coating Liquid 1 was changed to Coating Liquid 4.

[0154] [Comparative Example 6] A laminate 6C was obtained in the same manner as described above for the laminate 1 of Example 1, except that Coating Liquid 1 was changed to Coating Liquid 4.

[0155] [Comparative Example 7] A laminate 7C was obtained in the same manner as described above for the laminate 1 of Example 1, except that an inorganic vapor deposition layer was not formed and Coating Liquid 1 was changed to Coating Liquid 5.

[0156] [Measurement of Film Thickness of Coating Layer] The obtained laminate was embedded in an embedding resin, and the cross-section was exposed with a microtome. The cross-section of the laminate was observed using a scanning electron microscope (SEM). From the obtained SEM images, the thickness of the coating layer in the planar portion was measured at 10 points, and the average value was taken as the thickness of the coating layer.

[0157] <Evaluation> [Transparency] For each of the obtained laminates, the haze of the coating layer was measured using a haze meter (NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS-K7105-1981. Those with a haze value of 10% or less were evaluated as A, and those with a haze value exceeding 10% were evaluated as B. When the haze value is 10% or less, the laminate has the desired transparency. These results are shown in Table 1.

[0158] [Oxygen permeability] Each of the obtained laminates was cut out to a size of 20 cm × 20 cm and subjected to retort treatment at 0.2 MPa and 120 °C for 30 minutes using a storage-type retort kettle. The oxygen permeability of each sample after the retort treatment was measured using an oxygen permeation tester OXTRAN (registered trademark) 2 / 20 manufactured by Modern Control under the conditions of a temperature of 30 °C and a relative humidity of 70%. The measurement method conforms to JIS K-7126 Method B (isobaric method) and ASTM D3985, and the measured value is expressed in units of cm 3 / (m 2 ·day·MPa). Those with an oxygen permeability of 10 cm 3 / (m 2 ·day·MPa) or less were evaluated as A, and those exceeding 10 cm 3 / (m 2 ·day·MPa) were evaluated as B. When the oxygen permeability is 10 cm 3 / (m 2 ·day·MPa) or less, the laminate has the desired gas barrier property in a high-temperature and high-humidity environment. These results are shown in Table 1.

[0159]

Table 1

[0160] As shown in Table 1, the laminates 1 to 5 (Examples 1 to 5) according to the present embodiment were excellent in both transparency and gas barrier properties in a high-temperature and high-humidity environment.

[0161] Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist thereof at the implementation stage. Also, the respective embodiments may be implemented in appropriate combination, and in that case, the combined effects can be obtained. Furthermore, the above-described embodiment includes various inventions, and various inventions can be extracted by combinations selected from a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, if the problem can be solved and the effects can be obtained, the configuration from which these constituent elements are deleted can be extracted as an invention.

Explanation of Reference Numerals

[0162] 1 ··· Base material 2 ··· Inorganic vapor deposition layer 3 ··· Coating layer 4 ··· Anchor coat layer 10, 20 ··· Gas barrier laminate

Claims

1. A gas barrier laminate comprising a base material, an inorganic vapor deposition layer containing an inorganic oxide, and a coating layer in this order, wherein the coating layer contains a carboxyl group-containing polymer (a), polyvalent metal-containing particles (b), a surfactant (c), and a silicon-containing compound (d), and 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), hydrolyzates thereof, and condensates thereof, and the molar number of the carboxyl group contained in the carboxyl group-containing polymer (a) (a ｔ ), the molar ratio of the molar number of the silicon-containing compound (d) (d ｔ ) to the molar number of the carboxyl group contained in the carboxyl group-containing polymer (a) (d ｔ ) / (a ｔ ) is 0.15% or more and 6.10% or less, The gas barrier laminate is a cured film of a coating liquid in which the coating layer has a film thickness of 230 nm or more and 600 nm or less, the polyvalent metal-containing particles (b) are dispersed in an organic solvent, and the water content is 0 to 50,000 ppm by mass fraction. However, the molar ratio (d ｔ ) / (a ｔ ) in which (d ｔ ) is the number of moles obtained by converting the silicon-containing compound (d) into a 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 is an alkyl group having 1 to 6 carbon atoms, which may be the same or different, and Z １ is a group containing an epoxy group. In general formula (2), R ２ is a methyl group, R ３ is an alkyl group having 1 to 6 carbon atoms, which may be the same or different, and Z ２ is a group containing an epoxy group.

2. The gas barrier laminate according to claim 1, wherein the coating liquid has a water content within a range of 1,500 ppm or more and 50,000 ppm or less by mass fraction.

3. The gas barrier laminate according to claim 1 or 2, 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.

4. The gas barrier laminate according to any one of claims 1 to 3, wherein the polyvalent metal constituting the polyvalent metal-containing particles (b) is a divalent metal.

5. The gas barrier laminate according to any one of claims 1 to 4, further comprising an anchor coat layer between the base material and the inorganic vapor deposition layer.

6. A packaging material containing the gas barrier laminate according to any one of claims 1 to 5.

7. A package containing the packaging material according to claim 6.

8. A packaged article containing the package according to claim 7 and the contents accommodated in the package.

9. A method for producing the gas barrier laminate according to any one of claims 1 to 5, comprising forming the coating layer from a coating liquid for forming a gas barrier coating layer containing the carboxy group-containing polymer (a), the polyvalent metal-containing particles (b), the surfactant (c), the silicon-containing compound (d), and the organic solvent (e), wherein the molar ratio (dt) / (at) of the number of moles (dt) of the silicon-containing compound (d) to the number of moles (at) of the carboxy group contained in the carboxy group-containing polymer (a) is 0.15% or more and 6.10% or less, the water content is 0% or more and 50,000 ppm or less by mass fraction, and the polyvalent metal-containing particles (b) are dispersed.

10. The production method according to claim 9, wherein the coating liquid has a water content within a range of 1,500 ppm or more and 50,000 ppm or less by mass fraction.

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