GAS BARRIER MATERIALS AND PACKAGING MATERIALS

Abstract

The invention proposes a gas barrier layer material comprising: (A) a layer (A) containing an olefin-based substrate with an inorganic layer formed on at least one of its surfaces; and (B) a layer (B) containing an ammonium salt of a resin with a carboxy group and from 0.1 to 0.5 chemical equivalents of a polyvalent metal compound relative to the carboxy group in the ammonium salt of the resin with a carboxy group, wherein layer (B) contains an ammonium salt of a resin (P1) with a carboxy group and a bulk average molecular weight from 3,000 to 200,000 and an ammonium salt of a resin (P2) with a carboxy group and a bulk average molecular weight from 200,000 to 10,000,000 in the range P2 / P1 = from 10 to 2,000, and proposes a packaging material.

Description

Gas barrier laminate and packaging material

[0001] The present invention relates to a gas barrier laminate and a packaging material obtained by using the gas barrier laminate.

[0002] Packaging materials used for packaging foods, daily necessities, pharmaceuticals, etc. are required to have properties such as strength, resistance to cracking, and gas barrier properties in order to protect the contents from shocks received during distribution, deterioration due to oxygen and moisture, etc. Since it is difficult for a single material to satisfy these required properties, laminates made by bonding different types of polymer materials together are widely used as packaging materials.

[0003] Examples of gas barrier laminate films include a gas barrier laminate obtained by applying a gas barrier coating liquid containing an ammonium salt (A) of a carboxyl-containing polymer, a particulate polyvalent metal compound (B), and water, wherein the content of the polyvalent metal compound (B) is 0.5 to 2.0 chemical equivalents relative to the carboxyl groups of the ammonium salt (A), and the average particle size of the polyvalent metal compound (B) is 4 μm or less, to a substrate and drying the coating layer (see, for example, Patent Document 1). The gas barrier laminate disclosed in Patent Document 1 is designed to function as a packaging material for distribution. The laminate is formed by applying an anchor coat layer to a biaxially oriented polyethylene terephthalate film, applying a gas barrier coating liquid thereon and drying the coating layer, dry-laminating a biaxially oriented nylon film to the surface of the coating layer via a two-component adhesive, and then dry-laminating the biaxially oriented nylon film and an unstretched polypropylene film via the same adhesive. The laminate was evaluated as a laminate of different resins (see the examples in Patent Document 1).

[0004] Meanwhile, in recent years, there has been a growing demand for packaging materials that are not only functional but also recyclable. There have been concerns that laminate films made of different resins, which are solely designed for functionality, degrade the quality of recycled plastics. Therefore, laminate films made of the same resin, such as olefin-based resins, are expected to be recyclable packaging materials. When the gas barrier coating liquid disclosed in Patent Document 1 is combined with a polyolefin resin film, the desired gas barrier properties are achieved, but flexibility tends to be poor. In particular, the coating layer may not follow the bending or stretching of the polyolefin resin film, resulting in cracks and other problems. Furthermore, the gas barrier coating liquid disclosed in Patent Document 1 exhibits poor liquid stability when using an ammonium salt (A) of a polymer having a high molecular weight carboxy group, resulting in a short usable time for the gas barrier coating liquid. When a low-molecular-weight ammonium salt (A) of a polymer having a carboxy group is used, film formation is not possible, resulting in poor gas barrier properties.

[0005] JP 2014-94972 A

[0006] An object of the present invention is to provide a gas barrier laminate and a packaging material which are suitable for obtaining a packaging material which has an excellent balance between gas barrier properties and flexibility and is also recyclable, by combining a gas barrier coating liquid which has excellent liquid stability and film-forming properties with a plastic film such as an olefin film.

[0007] The present inventors have found that a gas barrier laminate having an excellent balance between gas barrier properties and flexibility can be obtained by combining a (B) layer having a gas barrier property and containing a polyvalent metal compound in a specific range with an (A) layer made of an olefin-based base material on which an inorganic layer has been formed. Furthermore, the present inventors have found that a gas barrier laminate having even better flexibility can be obtained by using a (B) layer containing a polyvalent metal compound in a specific range and containing a hydroxyl group-containing compound such as glycerin as the (B) layer.

[0008] That is, the present invention provides a gas barrier laminate comprising: (A) layer (A) made of an olefin-based base material having an inorganic layer formed on at least one surface thereof; and (B) layer (B) containing an ammonium salt of a resin having a carboxyl group, and a polyvalent metal compound in an amount of 0.1 to 0.5 chemical equivalents relative to the carboxyl group of the ammonium salt of the resin having a carboxyl group, wherein layer (B) contains an ammonium salt of a resin (P1) having a carboxyl group and a weight-average molecular weight of 3,000 to 200,000, and an ammonium salt of a resin (P2) having a carboxyl group and a weight-average molecular weight of 200,000 to 10,000,000, with P2 / P1 being in the range of 10 to 2,000.

[0009] The present invention also provides a packaging material comprising the gas barrier laminate described above.

[0010] The present invention also provides a packaging material obtained by laminating the above-described gas barrier laminate and a second substrate with an adhesive.

[0011] According to the present invention, it is possible to obtain a gas barrier laminate and a packaging material which are suitable for obtaining a packaging material that is excellent in balance between gas barrier properties and flexibility and is also recyclable by combining a plastic film such as an olefin film.

[0012] In this specification, "to" means equal to or greater than the value before "to" and equal to or less than the value after "to".

[0013] ((A) Layer (A) Composed of a Substrate Having an Inorganic Layer Formed on at Least One Surface) The gas barrier laminate of the present invention has (A) a layer (hereinafter sometimes referred to as layer (A)) composed of a substrate having an inorganic layer formed on at least one surface. The substrate used in layer (A) in the present invention is not particularly limited in terms of material, manufacturing method, or shape as long as the effects of the present invention can be obtained, but is often in the form of a film (although it may also be called a sheet, it will be referred to as a film in the present invention). Examples of materials for these substrates include olefin-based resins such as polyethylene (PE), polypropylene (PP), cyclic olefin polymer (COP), and cyclic olefin copolymer (COC), polyester, acrylic, polycarbonate, cellulose ester, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), nylon (NY), and materials containing biomass-derived components. In particular, any film composed of a thermoplastic resin primarily composed of an olefin-based resin can be used without any particular limitation. Specific examples of olefin resins include polyethylenes such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, and linear low-density polyethylene, polypropylene (PP), ethylene-propylene copolymers, α-olefin polymers, ethylene-vinyl acetate copolymers, ethylene-vinyl alcohol copolymers, ethylene-acrylic acid copolymers, ethylene-methyl methacrylate copolymers, ethylene-ethyl acrylate copolymers, cyclic olefin resins, ionomer resins, and polymethylpentene; and modified olefin resins obtained by modifying olefin resins with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, or other unsaturated carboxylic acids. Among these, olefin resins such as polyethylene (PE), polypropylene (PP), cyclic olefin polymers (COP), and cyclic olefin copolymers (COC) are preferably used because the effects of the present invention are most pronounced, with polyethylene (PE) and polypropylene (PP) being most preferred.

[0014] Examples of film names for food packaging include polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film, MDOPE: uniaxially oriented polyethylene film, OPE: biaxially oriented polyethylene film), polyolefin films such as polypropylene film (CPP: unoriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. It is also preferable to use biomass films formed from materials containing biomass-derived components. Biomass films are sold by various companies, and sheets such as those listed in the list of biomass-certified products listed by the Japan Organics Resources Association, a general incorporated foundation, can be used.

[0015] The substrate used in Layer (A) is not particularly limited, and may be a substrate with a thickness typically used for packaging foods, daily necessities, pharmaceuticals, etc. From the viewpoint of formability and transparency, a film having a thickness in the range of 1 μm to 500 μm is sufficient, preferably 1 μm to 300 μm, and more preferably 1 μm to 100 μm. A thickness below 1 μm may result in insufficient strength, while a thickness above 500 μm may result in excessive rigidity, making processing difficult. The method for producing these substrates is not particularly limited, and they may be produced using various film-forming methods such as melt extrusion molding, solution casting molding, and calendar molding. These may also be further subjected to biaxial or uniaxial stretching. Furthermore, films that have been subjected to various surface treatments may also be used as needed.

[0016] The layer (A) is a layer having a substrate layer with an inorganic layer formed on at least one side thereof, and the inorganic layer is formed on a part or the entire surface of at least one side of the substrate. The inorganic substance forming the inorganic layer is not particularly limited as long as the effects of the present invention can be obtained, but it is preferable to use one or more selected from metals and metal oxides such as aluminum oxide, silicon oxide, aluminum, zinc oxide, magnesium oxide, calcium oxide, and zirconium oxide, and it is particularly preferable to use one or more selected from aluminum oxide, silicon oxide, aluminum, zinc oxide, and magnesium oxide because they exhibit good barrier properties.

[0017] In the (A) layer of the present invention, the method for forming the inorganic layer is not particularly limited as long as the effects of the present invention can be obtained. However, it can be formed by vapor deposition, sputtering, CVD, or coating. Vapor deposition and sputtering are particularly preferred because they allow for uniform formation of the inorganic layer. Furthermore, an anchor coat layer can be formed on the substrate layer before the inorganic layer is formed. The anchor coat layer may be formed by coating with a known anchor coating agent. For example, anchor coating agents primarily composed of acrylic resins, urethane resins, vinyl alcohol resins, ethylene vinyl alcohol resins, or other resins, or curable anchor coating agents that also contain an isocyanate or epoxy curing agent can be used. The thickness of the anchor coat layer is not particularly limited, but it is often formed in the range of 0.01 to 0.5 μm.

[0018] The thickness of the inorganic layer may be within a range that allows the effects of the present invention to be obtained, but is preferably in the range of 1 to 100 nm, and more preferably in the range of 3 to 80 nm.

[0019] From the viewpoint of recycling, it is preferable that the layer structure is as simple as possible, but from the viewpoint of distribution of the packaging material, printing is often required to indicate the contents of the packaging material or a description or name of the product. Printing is often also performed on the substrate.

[0020] (Printed Layer) The printed layer is a layer on which characters, figures, symbols, and other desired designs are printed. The printing method and printing ink are not particularly limited, and known printing methods and printing inks can be used. Printing inks using methods such as gravure printing, flexographic printing, lithographic offset printing, and inkjet recording printing are often used for the film used as the substrate. Printing inks that combine these printing methods with methods of curing using active energy rays such as ultraviolet (UV), LED, and electron beam (EB), or methods of curing using heat, are also used. Depending on the solvent used, inks may be referred to as aqueous inks or organic solvent-based inks.

[0021] Specific examples include gravure printing ink and flexographic printing ink (in some industries, gravure printing ink and flexographic printing ink are sometimes referred to as liquid printing ink), ultraviolet-curable ink for lithographic offset printing, electron-beam-curable ink for lithographic offset printing, ultraviolet-curable ink for inkjet recording and printing, and electron-beam-curable ink for inkjet recording and printing.

[0022] The position at which the printed layer printed using these inks is provided is arbitrary, and it may be provided on the first substrate, or a substrate on which a separate printed layer is provided may be one of the constituent components of the laminate of the present invention, and the position is arbitrary. The ink may contain a resin, a colorant, and a solvent as essential components, or it may be a so-called clear ink that contains a resin and a solvent but does not substantially contain a colorant. Below, we will explain the liquid printing inks that are most commonly used for printing on films.

[0023] The resin used in the liquid printing ink is not particularly limited and includes, for example, acrylic resin, polyester resin, styrene resin, styrene-maleic acid resin, maleic acid resin, polyamide resin, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyvinyl chloride resin, chlorinated polypropylene resin, cellulose-based resin, epoxy resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc., and one or more of these can be used in combination. Preferably, at least one or two or more selected from polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, and cellulose-based resin are used.

[0024] Colorants used in liquid printing inks include inorganic pigments such as titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite; organic pigments such as soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments; and extender pigments such as calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

[0025] Liquid printing inks for film printing are often organic solvent-based inks. The organic solvent used preferably does not contain an aromatic hydrocarbon organic solvent. More specific examples include alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol; ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbon-based organic solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon-based organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane. These may be used alone or in combination of two or more.

[0026] (Gas Barrier (B) Layer) The present invention is characterized by having the (A) layer and a (B) layer having gas barrier properties (hereinafter may be referred to as the gas barrier (B) layer). The gas barrier (B) layer contains an ammonium salt of a resin having a carboxyl group, and a polyvalent metal compound in an amount of 0.1 to 0.5 chemical equivalents relative to the carboxyl group of the ammonium salt of the resin having a carboxyl group.

[0027] (Resin Having a Carboxyl Group) In the resin having a carboxyl group (sometimes referred to as a carboxylic acid group) used in the present invention, the carboxyl group may be in the form of a carboxylic acid anhydride.

[0028] (Acid Value) For resins having carboxyl groups, an acid value of 50 to 1000 mgKOH / g is preferred because it improves barrier performance. An acid value of 80 to 900 mgKOH / g is particularly preferred. If the acid value is 80 mgKOH / g or higher, ionic bonding will progress sufficiently and high barrier performance will be obtained.

[0029] (Method for Measuring Acid Value) The acid value is the number of milligrams of potassium hydroxide required to neutralize the acid content present in 1 g of sample. Specifically, the acid value can be measured by dissolving a weighed sample in an appropriate solvent in which the sample is soluble, for example, a solvent with a volume ratio of toluene / methanol = 70 / 30, adding several drops of a 1% phenolphthalein alcohol solution, adding a 0.1 mol / L potassium hydroxide alcohol solution thereto, and checking the point of discoloration, and can be calculated using the following formula:

[0030] Acid value measurement method-1 Acid value (mg KOH / g) = (V x F x 5.61) / S V: Amount (mL) of 0.1 mol / L potassium hydroxide alcohol solution used F: Potency of 0.1 mol / L potassium hydroxide alcohol solution S: Amount (g) of sample collected 5.61: Amount (mg) of potassium hydroxide equivalent in 1 mL of 0.1 mol / L potassium hydroxide alcohol solution

[0031] When the sample is a resin solution, the resin acid value (mgKOH / g) can be calculated using the following formula.

[0032] Resin acid value (mg KOH / g) = Acid value of resin solution (mg KOH / g) / NV (%) × 100 NV: Non-volatile content (%)

[0033] Furthermore, if the sample has low solubility in an organic solvent and precipitates, making measurement difficult, the acid value can also be measured by the following method.

[0034] Acid value measurement method-2 The acid value (mg KOH / g-resin) is a value calculated using the following formula using an FT-IR (FT-IR4200 manufactured by JASCO Corporation) and the coefficient (f) obtained from a calibration curve prepared using a chloroform solution of maleic anhydride, the absorbance (I) of the stretching peak of the anhydride ring of maleic anhydride (1780 cm-1) in the maleic anhydride-modified polyolefin solution, and the absorbance (II) of the stretching peak of the carbonyl group of maleic acid (1720 cm-1). Acid value (mg KOH / g-resin) = [(absorbance (I) x (f) x 2 x molecular weight of potassium hydroxide x 1000 (mg) + absorbance (II) x (f) x molecular weight of potassium hydroxide x 1000 (mg)) / molecular weight of maleic anhydride] Molecular weight of maleic anhydride: 98.06, molecular weight of potassium hydroxide: 56.11

[0035] (Molecular Weight) The present invention is characterized in that the resin having a carboxyl group used is a mixture of a resin (P1) having a weight-average molecular weight of 3,000 to 200,000 and a resin (P2) having a weight-average molecular weight of 200,000 to 10,000,000. This mixture improves the liquid stability of the coating agent that forms the gas barrier (B) layer, described below. The ratio of the mixture, P2 / P1, is preferably in the range of 10 to 2,000, more preferably 30 to 500.

[0036] The weight average molecular weight of the resin having a carboxyl group of the present invention is a value calculated by measuring using a gel permeation chromatograph (GPC), and specifically, is a value measured by the following method.

[0037] In the present invention, the measurement of the weight average molecular weight (pullulan equivalent) by GPC was carried out using an L20 system manufactured by Shimadzu Corporation under the following conditions: Separation column: Shodex OHpak SB-806MHQ Column temperature: 40°C Mobile phase: 0.2 mol / L aqueous sodium nitrate solution Flow rate: 0.70 mL / min Sample injection amount: 50 μL Detector: RI, UV wavelength 254 nm

[0038] The weight average molecular weight of the resin (P1) is preferably in the range of 5,000 to 150,000, more preferably 6,000 to 100,000, while the weight average molecular weight of the resin (P2) is preferably in the range of 300,000 to 5,000,000, more preferably 400,000 to 2,000,000.

[0039] The resin having carboxyl groups used in the present invention is preferably neutralized with ammonium to form an ammonium salt. Whether or not it is neutralized can be determined by pH, and the pH of a 15% aqueous solution of the resin having carboxyl groups is preferably 7.0 to 9.0. If the pH is less than 7.0, the unneutralized resin having carboxyl groups will react with the metal ions of the polyvalent metal compound, resulting in the formation of aggregates. If the pH is greater than 9.0, the odor caused by ammonia may become a problem.

[0040] The ammonium used for neutralization is not particularly limited, but for example, a commonly available 30% aqueous ammonia solution can be used.

[0041] The resin having a carboxyl group is not particularly limited in terms of its resin skeleton, and any known resin can be used, with carboxyl group-containing vinyl resins being preferred.

[0042] (Carboxyl Group-Containing Vinyl Resin) Examples of the carboxyl group-containing vinyl resin include polymers of polymerizable unsaturated monomers having a carboxyl group. Examples of the polymerizable unsaturated monomers having a carboxyl group include unsaturated carboxylic acids such as (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, crotonic acid, itaconic acid, maleic acid, and fumaric acid;

[0043] Monoesters (half esters) of various unsaturated dicarboxylic acids with saturated monohydric alcohols, such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, and mono-n-butyl fumarate;

[0044] Monovinyl esters of various saturated dicarboxylic acids such as monovinyl adipate or monovinyl succinate;

[0045] Examples of the monomers include addition reaction products of various saturated polycarboxylic acid anhydrides, such as succinic anhydride, glutaric anhydride, phthalic anhydride, and trimellitic anhydride, with various hydroxyl group-containing vinyl monomers; and various monomers obtained by addition reaction of the above-mentioned various carboxyl group-containing monomers with lactones.

[0046] The resin having a carboxyl group used in the present invention may be a homopolymer of the above-mentioned polymerizable unsaturated monomer having a carboxyl group, or a copolymer using a plurality of polymerizable unsaturated monomers having a carboxyl group, or a copolymer of a polymerizable unsaturated monomer having a carboxyl group and another copolymerizable monomer.

[0047] Examples of the monomer copolymerizable with the polymerizable unsaturated monomer having a carboxyl group include the following.

[0048] (1) (meth)acrylic acid esters having an alkyl group having 1 to 22 carbon atoms, such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, t-butyl (meth)acrylate, hexyl (meth)acrylate, hepsyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, dodecyl (meth)acrylate, tetradecyl (meth)acrylate, hexadecyl (meth)acrylate, stearyl (meth)acrylate, octadecyl (meth)acrylate, and docosyl (meth)acrylate;

[0049] (2) (meth)acrylic acid esters having an alicyclic alkyl group, such as cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate; (3) (meth)acrylic acid esters having an aromatic ring, such as benzoyloxyethyl (meth)acrylate, benzyl (meth)acrylate, phenylethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate;

[0050] (4) Acrylic acid esters having a hydroxyalkyl group, such as hydroxyethyl (meth)acrylate; hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, glycerol (meth)acrylate; (meth)acrylic acid esters having a polyalkylene glycol group, such as lactone-modified hydroxyethyl (meth)acrylate, polyethylene glycol (meth)acrylate, and polypropylene glycol (meth)acrylate;

[0051] (5) Unsaturated dicarboxylic acid esters such as dimethyl fumarate, diethyl fumarate, dibutyl fumarate, dimethyl itaconate, dibutyl itaconate, methyl ethyl fumarate, methyl butyl fumarate, and methyl ethyl itaconate; (6) Styrene derivatives such as styrene, α-methylstyrene, and chlorostyrene; (7) Diene compounds such as butadiene, isoprene, piperylene, and dimethylbutadiene; (8) Vinyl halides and vinylidene halides such as vinyl chloride and vinyl bromide; (9) Unsaturated ketones such as methyl vinyl ketone and butyl vinyl ketone; (10) Vinyl esters such as vinyl acetate and vinyl butyrate; (11) Vinyl ethers such as methyl vinyl ether and butyl vinyl ether; (12) Vinyl cyanides such as acrylonitrile, methacrylonitrile, and vinylidene cyanide; (13) Acrylamide and its alkyd-substituted amides; (14) N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide;

[0052] (15) Fluorine-containing α-olefins such as vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene, or hexafluoropropylene; or (per)fluoroalkyl perfluorovinyl ethers in which the (per)fluoroalkyl group has 1 to 18 carbon atoms, such as trifluoromethyl trifluorovinyl ether, pentafluoroethyl trifluorovinyl ether, or heptafluoropropyl trifluorovinyl ether; fluorine-containing ethylenically unsaturated monomers such as (per)fluoroalkyl (meth)acrylates in which the (per)fluoroalkyl group has 1 to 18 carbon atoms, such as 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoropentyl (meth)acrylate, 1H,1H,2H,2H-heptadecafluorodecyl (meth)acrylate, or perfluoroethyloxyethyl (meth)acrylate;

[0053] (16) silyl group-containing (meth)acrylates such as γ-methacryloxypropyltrimethoxysilane; and (17) N,N-dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and N,N-diethylaminopropyl (meth)acrylate. These polymerizable unsaturated monomers may be used alone or in combination of two or more.

[0054] The resin having a carboxyl group can be obtained by polymerization (copolymerization) using a known, commonly used method, and the copolymerization form is not particularly limited. It can be produced by addition polymerization in the presence of a catalyst (polymerization initiator), and may be any of a random copolymer, a block copolymer, a graft copolymer, etc. Furthermore, known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used as the copolymerization method.

[0055] The content of the ammonium salt of the resin having a carboxyl group in the layer (B) is preferably 45 to 95% by mass, and more preferably 55 to 93% by mass, based on the solid content of the layer (B).

[0056] (Polyvalent Metal Compound) The polyvalent metal compound used in the present invention is preferably a divalent metal compound. Examples of the divalent metal compound include zinc compounds, magnesium compounds, calcium compounds, manganese compounds, iron compounds, cobalt compounds, nickel compounds, and copper compounds, and zinc compounds, magnesium compounds, and calcium compounds are particularly preferred. These metal compounds may be used alone or in combination of two or more.

[0057] The divalent metal compound is preferably an oxide, hydroxide, or carbonate of a divalent metal, and may be a mixture of these. Specific examples of the divalent metal compound (B) include zinc oxide, magnesium oxide, and calcium oxide, and particularly preferably zinc oxide and magnesium oxide.

[0058] The divalent metal compound is preferably in the form of particles. More preferably, it is fine particles having an average particle size of 10 nm or more and 500 nm or less. Particularly preferably, it is fine particles having an average particle size of 20 nm to 300 nm. The average particle size here can be measured using a dynamic light scattering particle size distribution analyzer, for example, LB-500 (manufactured by Horiba, Ltd.).

[0059] The polyvalent metal compound is preferably contained in an amount of 0.1 to 0.5 chemical equivalents relative to the carboxyl groups of the ammonium salt of the resin having a carboxyl group. It is preferably contained in an amount of 0.2 to 0.48 chemical equivalents, more preferably 0.3 to 0.46 chemical equivalents. If the amount is less than 0.1 equivalent, crosslinking of the resin having a carboxyl group by the metal ions of the polyvalent metal compound is insufficient, resulting in poor gas barrier properties. If the amount is more than 0.5 equivalents, the coating film becomes hard due to ionic crosslinking, and the gas barrier (B) layer does not conform to bending or stretching of the polyolefin resin film, resulting in cracks and other problems.

[0060] In the present invention, the chemical equivalent is calculated and referred to as follows. For example, the molecular weight of a unit of ammonium polyacrylate, which is a resin having a carboxyl group, is 89. Normally, for every two molecules of ammonium polyacrylate (twice the molecular weight of 89), one molecule of zinc oxide (molecular weight 81.4), a polyvalent metal compound, contributes to the reaction and forms a salt. A formulation in which the weight of ammonium polyacrylate and the weight of zinc oxide are mixed in a ratio of 178 / 81.4 = 100 / 45.7 is referred to as mixing one equivalent of zinc oxide.

[0061] (Additives) The gas barrier layer (B) may contain various additives in addition to the resin having a carboxyl group and the polyvalent metal compound. Examples of additives include hydroxyl group-containing compounds, coupling agents, silane compounds, phosphate compounds, organic fillers, inorganic fillers, stabilizers (antioxidants, heat stabilizers, UV absorbers, etc.), plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, nucleating agents, oxygen scavengers (compounds with oxygen-scavenging function), and tackifiers. These various additives may be used alone or in combination of two or more.

[0062] (Hydroxyl Group-Containing Compound) The gas barrier (B) layer preferably contains a hydroxyl group-containing compound having a boiling point of 120°C or higher, and a hydroxyl group-containing compound having a plasticizing effect on resins and / or a hydroxyl group-containing compound having an effect of improving the coatability of aqueous materials on substrates is preferred. Examples of hydroxyl group-containing compounds that function as plasticizers include butanol, hexanol, pentanol, ethylene glycol, trimethylene glycol, propylene glycol, tetramethylene glycol, 1,3-butanediol, 2,3-butanediol, pentamethylene glycol, hexamethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polyethylene oxide, sorbitol, mannitol, dulcitol, erythritol, glycerin, lactic acid, fatty acids, starch, and phthalate esters. Of these, glycerin is preferred. Examples of hydroxyl group-containing compounds that function as wetting agents include acetylene glycol, ethylene oxide adducts of acetylene alcohol, ethylene oxide adducts of acetylene glycol, ethylene oxide-propylene oxide block copolymers, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, and other ether-based compounds such as polyoxyalkylene alkyl ethers; polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, and polyoxyethylene stearate; silicon-based compounds such as dimethylpolysiloxane; and fluorine-containing compounds such as fluorine alkyl esters and perfluoroalkyl carboxylates. Among these, acetylene glycol, an ethylene oxide adduct of acetylene glycol, and an ethylene oxide-propylene oxide block copolymer are preferred.By setting the boiling point at 120° C. or higher, it is possible to prevent the volatilization of the hydroxyl group-containing compound.

[0063] The hydroxyl group-containing compound may have a carbonyl group, but is desirably neutralized with an amine such as ammonium or an alkali metal such as sodium or potassium, which can prevent aggregation of the polyvalent metal compound with metal ions.

[0064] The hydroxyl group-containing compound contributes to the stretchability and flexibility of the layer (B), making it a layer that easily conforms to the layer (A) made of an olefin-based base material on which an inorganic layer is formed, thereby improving abuse resistance.

[0065] The hydroxyl group-containing compound is preferably contained in an amount of 0.04 to 15% by mass, and more preferably 0.05 to 10% by mass, based on the solid content of the (B) layer. If the amount is less than 0.04% by mass, the stretchability of the gas barrier (B) layer and / or the coatability of aqueous materials to the substrate may not be improved, and the abuse resistance may not be improved. If the amount is more than 15% by mass, problems such as migration and bleed-out may occur.

[0066] The gas barrier layer (B) preferably contains at least one compound (S) selected from the group consisting of silicon compounds represented by general formula (s1) and hydrolysates thereof, which not only improves gas barrier properties but also maintains the appearance of the pouch after retort. The inclusion of compound (S) can improve hot water resistance after pouch formation.

[0067] (R １ O) ３ Si-(CH ２ ) ｎ -R ２ ....(s1)

[0068] In general formula (s1), R １ represents an alkyl group. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and most preferably an alkyl group having 1 to 3 carbon atoms. Examples of such an alkyl group include a methyl group, an ethyl group, and a propyl group.

[0069] In general formula (s1), R２ is an organic group having an epoxy group or an amino group. ２ Among these, an organic group having an amino group is preferred, and an amino group having two or more nitrogen atoms is preferred. Specific examples include a glycidoxy group, a 3,4-epoxycyclohexyl group, an amino group, an N-phenylamino group, and an N-2-(aminoethyl)amino group.

[0070] In general formula (s1), n ​​is an integer of 1 to 10. Of these, n is preferably 3 to 10, more preferably 4 to 10, and even more preferably 6 to 10.

[0071] Specific examples of the compound (S) include 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 8-glycidoxyoctyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, and N-2-(aminoethyl)-8-aminooctyltrimethoxysilane. Among these, 3-glycidoxypropyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 3-aminopropyltriethoxysilane, and N-2-(aminoethyl)-8-aminooctyltrimethoxysilane are preferred, 3-aminopropyltriethoxysilane and N-2-(aminoethyl)-8-aminooctyltrimethoxysilane are more preferred, and N-2-(aminoethyl)-8-aminooctyltrimethoxysilane is most preferred.

[0072] The compound (S) is preferably contained in an amount of 10 to 30% by mass, and more preferably 11 to 28% by mass, relative to the solid content of the gas barrier (B) layer. If the amount is less than 10% by mass, it may be difficult to achieve the effect of maintaining the appearance after retort. On the other hand, if the amount exceeds 30% by mass, the liquid stability of the coating agent that forms the gas barrier (B) layer described below may be reduced.

[0073]

[0033] (Volatile Solvent) Since the gas barrier (B) layer is formed as a coating film by applying and drying on the (A) layer, it is preferable that the coating agent that forms the gas barrier (B) layer (hereinafter, the coating agent that forms the gas barrier (B) layer will be referred to as coating agent (B)) contains a volatile solvent. There are no particular limitations on the volatile solvent, but from the viewpoint of drying properties and the solubility of the ammonium salt of the resin having a carboxyl group, it is preferable to use water or a combination of two or more organic solvents that are soluble in water and have a boiling point of less than 120°C. Examples of the volatile solvent include alcohol-based organic solvents such as ethanol, n-propanol, isopropyl alcohol, and butanol; ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; and ester-based organic solvents such as methyl acetate and ethyl acetate.

[0074] In the coating agent (B), the nonvolatile content is preferably 0.5% to 20% of the composition. Furthermore, the total amount of the carboxyl group-containing resin (A) and the divalent metal compound (B) is preferably 70% to 100% of the total nonvolatile content. This range allows for sufficient gas barrier properties to be exhibited. A range of 80% to 100% is particularly preferred.

[0075] The coupling agent may be any known or commonly used one, such as a silane coupling agent, a titanium coupling agent, a zirconium coupling agent, or an aluminum coupling agent.

[0076] Any known or commonly used silane coupling agent may be used, and examples thereof include (meth)acryloyl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane.

[0077] Examples of titanium coupling agents include isopropyl triisostearoyl titanate, isopropyl trioctanoyl titanate, isopropyl dimethacrylisostearoyl titanate, isopropyl isostearoyl diacryl titanate, isopropyl tris(dioctyl pyrophosphate)titanate, tetraoctylbis(ditridecylphosphite)titanate, tetra(2,2-diallyloxymethyl-1-butyl)bis(ditridecyl)phosphite titanate, bis(dioctyl pyrophosphate)oxyacetate titanate, bis(dioctyl pyrophosphate)ethylene titanate, titanium lactate ammonium salt, titanium lactate, titanium triethanolaminate, titanium lactate, titanium lactate ammonium salt, titanium diethanolaminate, and titanium aminoethylaminoethanolate.

[0078] Examples of zirconium coupling agents include zirconium acetate, ammonium zirconium carbonate, zirconium fluoride, zirconyl chloride compounds, and zirconium lactate ammonium salts.

[0079] Examples of aluminum coupling agents include acetoalkoxy aluminum diisopropylate, aluminum diisopropoxymonoethyl acetoacetate, aluminum trisethyl acetoacetate, and aluminum trisacetylacetonate.

[0080] Examples of silane compounds include alkoxysilanes, silazanes, and siloxanes. Examples of alkoxysilanes include methyltrimethoxysilane, dimethyldimethoxysilane, phenyltrimethoxysilane, methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, hexyltrimethoxysilane, hexyltriethoxysilane, octyltriethoxysilane, decyltrimethoxysilane, 1,6-bis(trimethoxysilyl)hexane, and trifluoropropyltrimethoxysilane. Examples of silazanes include hexamethyldisilazane. Examples of siloxanes include hydrolyzable group-containing siloxanes.

[0081] Among the additives, inorganic fillers include inorganic substances such as metals, metal oxides, resins, and minerals, as well as composites thereof. Specific examples of inorganic fillers include silica, alumina, titanium, zirconia, copper, iron, silver, mica, talc, aluminum flakes, glass flakes, and clay minerals.

[0082] Examples of compounds having an oxygen-scavenging function include low-molecular-weight organic compounds that react with oxygen, such as hindered phenol compounds, vitamin C, vitamin E, organic phosphorus compounds, gallic acid, and pyrogallol, and transition metal compounds, such as cobalt, manganese, nickel, iron, and copper.

[0083] Examples of tackifiers include xylene resins, terpene resins, phenolic resins, and rosin resins. Addition of a tackifier can improve adhesion to various substrates immediately after application. The amount of tackifier added is preferably 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the resin composition.

[0084] The procedure for producing the coating agent (B) is preferably such that the polyvalent metal compound is dispersed in an aqueous solution of a resin (P1) having a carboxyl group and a weight-average molecular weight of 3,000 to 200,000, and the resulting dispersion is mixed with a solvent such as water or alcohol, a resin (P2) having a carboxyl group and a weight-average molecular weight of 200,000 to 10,000,000, and an additive such as a hydroxyl group-containing compound, from the viewpoint of liquid stability.

[0085] The gas barrier (B) layer can be obtained by applying the coating agent (B) to the (A) layer to obtain a laminate having gas barrier properties. When the coating agent (B) is applied to the inorganic layer of the (A) layer, the volatile solvent is removed, and the resin having a carboxyl group and the polyvalent metal compound form an ionic bond, and the resulting crosslinked structure exhibits barrier properties.

[0086] The thickness of the gas barrier (B) layer is not particularly limited as long as the effects of the present invention can be obtained, but it is preferably in the range of 0.05 to 1 μm, and more preferably in the range of 0.1 to 0.5 μm. This is because the coating agent (B) is applied to a thickness of approximately 0.05 to 1 g / m2 in solid content. ２ This is achieved by coating in an amount of

[0087] The coating method for the coating agent (B) is not particularly limited, and any known and commonly used coating method can be used, such as spraying, spin coating, dipping, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, inkjet printing, and dispensing. In particular, roll coating using a gravure coater is preferred because it allows for the formation of a good coating film.

[0088] The gas barrier (B) layer obtained by applying the coating agent (B) is dried after application to further increase the density of ionic bonds within the coating layer. Therefore, it is preferable to provide a drying step after application. The drying step may be performed at room temperature, or may be performed by forced drying using heating, reduced pressure, or air blowing.

[0089] (Second substrate) The laminate including the (A) layer and the gas barrier resin (B) layer can be bonded to a second substrate using an adhesive. Alternatively, the second substrate can be formed on the laminate by extrusion. The second substrate can be the same type as the (A) layer or a different type. When the laminate of the present invention is used as a packaging material, the second substrate can be used as a sealant layer, and a polyolefin resin having heat sealability can be selected for the second substrate. Examples of the heat-sealable layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), polypropylene (CPP), ethylene-propylene copolymers, and polymethylpentene; ethylene-vinyl acetate copolymers (EVA), ethylene-methyl methacrylate copolymers (EMMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-methyl acrylate (EMA) copolymers, ethylene-ethyl acrylate-maleic anhydride copolymers (E-EA-MAH), ethylene-acrylic acid copolymers (EAA), and ethylene-methacrylic acid copolymers (EMAA); and ionomers of ethylene-acrylic acid copolymers and ionomers of ethylene-methacrylic acid copolymers, which may be used alone or in combination of two or more. When the second layer is a heat-sealable layer, its thickness can be adjusted appropriately depending on the purpose, but is, for example, 1 μm to 10 μm, and more preferably 3 μm to 10 μm, from the viewpoints of aroma retention and heat-sealability.

[0090] (Adhesive) The adhesive used to bond the second layer to the laminate containing the (A) layer and the gas barrier resin (B) layer may be any adhesive that can be used in a general-purpose lamination method. Examples of lamination methods include dry lamination, wet lamination, non-solvent lamination, and extrusion lamination. The adhesive becomes an adhesive layer after curing or drying.

[0091] The adhesive used in the dry lamination may be, for example, a one-component or two-component curable or non-curable vinyl, (meth)acrylic, polyamide, polyester, polyether, polyurethane, epoxy, rubber, or other solvent-based, aqueous, or emulsion adhesive. A two-component curable adhesive may be a two-component curable adhesive composed of a polyol and an isocyanate compound. The laminating adhesive may be applied by, for example, direct gravure roll coating, gravure offset roll coating, kiss coating, reverse roll coating, Fountain coating, transfer roll coating, or other methods. For example, the DIC Dry series manufactured by DIC Corporation may be preferably used.

[0092] Various types of adhesives can also be used, and it is preferable to use a pressure-sensitive adhesive. Examples of pressure-sensitive adhesives include rubber-based adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, and hexane, or these rubber-based adhesives blended with tackifiers such as abiethylene acid rosin ester, terpene-phenol copolymer, and terpene-indene copolymer, and acrylic-based adhesives obtained by dissolving an acrylic copolymer having a glass transition temperature of −20° C. or lower, such as a 2-ethylhexyl acrylate-n-butyl acrylate copolymer or a 2-ethylhexyl acrylate-ethyl acrylate-methyl methacrylate copolymer, in an organic solvent.

[0093] The adhesive may be a functional adhesive. For example, an adhesive having gas barrier properties may be the oxygen barrier adhesive PASLIM series manufactured by DIC Corporation, which is a two-component reactive adhesive of polyester polyol and an isocyanate compound. The gas barrier adhesive becomes a gas barrier adhesive layer after curing or drying. Use of a gas barrier adhesive is preferred because it can further enhance the gas barrier properties of the laminate of the present invention.

[0094] When the adhesive is solvent-based, the adhesive is applied to one substrate using a roll such as a gravure roll, and the organic solvent is evaporated by heating in an oven or the like, and then the other substrate is laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 80°C, and the aging time is preferably 12 to 240 hours.

[0095] When the adhesive is solventless, the aroma-retaining adhesive, which has been preheated to about 40°C to 100°C, is applied to one substrate using a roll such as a gravure roll, and the other substrate is immediately laminated to obtain the laminate of the present invention. It is preferable to perform an aging treatment after lamination. The aging temperature is preferably room temperature to 70°C, and the aging time is preferably 6 to 240 hours.

[0096] The amount of adhesive to be applied is adjusted as appropriate. In the case of a solvent-based adhesive, for example, the solid content is 1 g / m ２ 10g / m or more ２ Preferably 1 g / m or less ２ 5g / m or more ２ In the case of a solvent-free type, the amount of adhesive applied is adjusted to, for example, 1 g / m ２ 10g / m or more ２ Preferably 1 g / m or less ２ 5g / m or more ２ The following is the result.

[0097] (Laminate Structure) An example of a specific embodiment of the laminate of the present invention is given below, but the laminate of the present invention is not limited to this embodiment. Layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Layer (A) / printed layer / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Printed layer / layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / substrate used as intermediate layer / adhesive layer / second substrate Layer (A) / printed layer / gas barrier resin (B) layer / gas barrier adhesive layer / substrate used as intermediate layer / adhesive layer / second substrate Printed layer / layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / substrate used as intermediate layer / adhesive layer / second substrate Layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Layer (A) / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Layer (A) / printed layer / gas barrier resin (B) layer / gas barrier adhesive layer / second substrate Printing layer / Layer (A) / Gas barrier resin (B) layer / Gas barrier adhesive layer / Second substrate Layer (A) / Gas barrier resin (B) layer / Gas barrier adhesive layer / Substrate used as intermediate layer / Adhesive layer / Second substrate Layer (A) / Printing layer / Gas barrier resin (B) layer / Gas barrier adhesive layer / Substrate used as intermediate layer / Adhesive layer / Second substrate Printing layer / Layer (A) / Gas barrier resin (B) layer / Gas barrier adhesive layer / Substrate used as intermediate layer / Adhesive layer / Second substrate Furthermore, a coating layer that imparts functions such as release properties and antistatic properties may be present on Layer (A).

[0098] (Packaging Material) The laminate of the present invention can be used as a multilayer packaging material for the purpose of protecting food, medicines, etc. When used as a multilayer packaging material, the layer structure can be changed depending on the contents, usage environment, and usage form. In addition, the packaging of the present invention may be appropriately provided with an easy-open treatment or resealable means.

[0099] Taking a laminate having a sealant layer as an example of the packaging material of the present invention, the laminates are stacked with the sealant layer surfaces facing each other, and then the peripheral edges are heat-sealed to form a bag. Examples of bag-making methods include folding or stacking the laminate of the present invention so that the inner layer surfaces (sealant layer surfaces) face each other, and heat-sealing the peripheral edges using, for example, a side seal, two-sided seal, three-sided seal, four-sided seal, envelope seal, flared seal, flat-bottom seal, square-bottom seal, gusset seal, or other heat seal methods. The packaging material of the present invention can take various forms depending on the contents, usage environment, and usage pattern. Self-standing packaging materials (standing pouches) are also possible. Heat sealing can be performed using known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal.

[0100] When the layer (A) and the second substrate of the laminate of the present invention do not function as a sealant layer that serves as a heat-sealing site when forming a packaging material, a further sealant layer may be added. The sealant layer may be an additional substrate bonded with the adhesive of the present invention, or may be an adhesive layer made of the adhesive of the present invention.

[0101] The packaging material of the present invention is filled with contents through its opening, and then the opening is heat-sealed to produce a product using the packaging material of the present invention. Examples of contents to be filled include foods such as rice crackers, bean snacks, nuts, biscuits, cookies, wafer snacks, marshmallows, pies, semi-dried cakes, candies, and snacks; staple foods such as bread, snack noodles, instant noodles, dried noodles, pasta, aseptically packaged cooked rice, porridge, rice porridge, packaged rice cakes, and cereal foods; processed agricultural products such as pickles, boiled beans, natto, miso, frozen tofu, tofu, nametake mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potatoes; processed livestock products such as ham, bacon, sausages, processed chicken, and corned beef; and processed fish ham and meat products. Examples of such foods include processed seafood products such as sausages, fish paste products, kamaboko, nori seaweed, tsukudani (simmered foods in soy sauce), bonito flakes, salted fish, smoked salmon, and spicy mentaiko; fruit pulp such as peaches, mandarin oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; cooked foods such as frozen and chilled prepared dishes, including hamburgers, meatballs, fried seafood, gyoza, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings, retort curry, and pet food.

[0102] In addition, the present invention can also be used as a packaging material for various non-food products, such as cigarettes, disposable body warmers, medicines such as infusion packs, liquid laundry detergent, liquid kitchen detergent, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotion and emulsion, vacuum insulation materials, batteries, etc.

[0103] (Recycled plastic) The laminate and packaging material can be reused as recycled plastic. Here, an example of a processing method for converting the laminate film into recycled plastic is shown. Of course, the present invention is not limited to this, and various known recycled plastic processing methods can be applied.

[0104] The laminate or packaging material is crushed using a crusher or the like. Any known crusher may be used, and there are no particular limitations on the crusher. The crushed film pieces are then physically blended using melt kneading, solvent cast blending, latex blending, polymer complexing, or the like. The melt kneading method is particularly common. Examples of kneading devices include a tumbler, Henschel mixer, rotary mixer, super mixer, ribbon tumbler, and V blender. The film is melt-kneaded using such a kneading device and then pelletized. A single-screw or multi-screw extruder is generally used for melt kneading and pelletizing. In addition to these extruders, a Banbury mixer, roller, co-kneader, blast mill, Prabender blotograph, or the like can also be used, and these can be operated batchwise or continuously. Alternatively, the film may be used as a molding resin without being melt-kneaded, and melt-kneaded in the heating barrel of a molding machine.

[0105] The present invention will be described in more detail below with reference to specific synthesis examples and examples, but the present invention is not limited to these examples. In the following examples, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0106] Definition: The molecular weight of a unit of ammonium polyacrylate, a resin with carboxyl groups, is 89. Normally, for every two molecules of ammonium polyacrylate (twice the molecular weight of 89), one molecule of zinc oxide (molecular weight 81.4), a polyvalent metal compound, contributes to the reaction and forms a salt. A formulation in which the weight of ammonium polyacrylate and the weight of zinc oxide are mixed in a ratio of 178 / 81.4 = 100 / 45.7 is said to contain 1 equivalent of zinc oxide.

[0107] (Evaluation item 1: liquid stability) The produced coating agent (B) was left to stand for 3 hours, and visually inspected for the presence of precipitation of fine particles. (Evaluation criteria) ○: No precipitation of fine particles in the coating agent △: A small amount of fine particles precipitated in the coating agent ×: Significant precipitation of fine particles in the coating agent

[0108] (Evaluation Item 2: Gas Barrier Property (Oxygen Permeability)) Oxygen permeability was measured in accordance with JIS-K7126-2:2006 "Plastics - Films and Sheets - Gas Permeability Test Methods - Part 2: Constant Pressure Method" using an oxygen permeability measuring device OX-TRAN2 / 21 manufactured by Mocon Co., Ltd., in an atmosphere of temperature 23°C and humidity 0% RH, and in an atmosphere of temperature 23°C and humidity 90% RH. RH represents relative humidity. The unit of oxygen permeability is cc / day·atm·m. ２ is.

[0109] (Evaluation item 3: Gas barrier properties (oxygen permeability) after flex test) The produced laminated film was cut into a size of 30 cm x 20 cm, and a flex test was carried out using a Gelbo Flex tester (BE-1006 Gelbo Flex tester with thermostatic bath, Tester Sangyo Co., Ltd.) in accordance with ASTM F392. The flex test was carried out under the conditions of 440° / 90 mm linear motion 65 mm, 23°C, and 30 flexes, and the oxygen permeability after Gelbo Flex treatment was measured.

[0110] (Preparation of Layer (A)) An anchor coating solution prepared by blending an acrylic coating agent (GAC-013S, DIC Corporation) and a polyisocyanate curing agent (KR-90, DIC Corporation) in a mixing ratio of 5:1 was applied to a biaxially stretched polypropylene film (OPP film FOR, Futamura Chemical Co., Ltd., thickness 20 μm) by gravure coating to a dry film thickness of approximately 0.05 μm, and then dried to obtain an anchor coat layer. Thereafter, metallic aluminum was vapor-deposited in a vacuum vapor deposition apparatus using an electron beam heating system, and oxygen gas was introduced. In this way, an (A) layer was formed having an anchor coat layer on the OPP film and an aluminum oxide vapor-deposited inorganic layer with a thickness of 20 nm thereon.

[0111] (Preparation of Polyvalent Metal Compound Dispersion Liquid (z-1)) For the polyvalent metal compound dispersion liquid, 30 parts of ZnO (FINEX-50, manufactured by Sakai Chemical Industry Co., Ltd.) having a primary particle size of 20 nm, 3.8 parts of an aqueous solution of ammonium polyacrylate (A-30SL, manufactured by Toagosei Co., Ltd., solid content rate: 40%) having a weight average molecular weight of 70,000 and a pH of 7.2, and 62.5 parts of water were mixed, and the mixture was dispersed in a bead mill (manufactured by Kotobuki Co., Ltd.: Ultra Aspek Mill UAM-015) using zirconia beads having a diameter of 0.3 mm for 1 hour, and the beads were then sieved to obtain a polyvalent metal compound dispersion liquid (z-1) having a solid content concentration of 31.5%.

[0112] (Preparation of Polyvalent Metal Compound Dispersion Liquid (z-2)) For the polyvalent metal compound dispersion liquid, 30 parts of ZnO (FINEX-50, manufactured by Sakai Chemical Industry Co., Ltd.) having a primary particle size of 20 nm, 7.5 parts of an aqueous solution of ammonium polyacrylate (A-30SL, manufactured by Toagosei Co., Ltd., solids content 40%) having a weight average molecular weight of 70,000 and a pH of 7.2, and 62.5 parts of water were mixed, and the mixture was dispersed in a bead mill (manufactured by Kotobuki Co., Ltd.: Ultra Aspek Mill UAM-015) using zirconia beads having a diameter of 0.3 mm for 1 hour, and the beads were then sieved to obtain a polyvalent metal compound dispersion liquid (z-2) having a solids concentration of 33.0%.

[0113] (Preparation of Polyvalent Metal Compound Dispersion Liquid (z-3)) For the polyvalent metal compound dispersion liquid, 30 parts of ZnO (FINEX-50, manufactured by Sakai Chemical Industry Co., Ltd.) having a primary particle size of 20 nm, 2.5 parts of an aqueous solution of ammonium polyacrylate (A-30SL, manufactured by Toagosei Co., Ltd., solid content rate: 40%) having a weight average molecular weight of 70,000 and a pH of 7.2, and 68.7 parts of water were mixed, and the mixture was dispersed in a bead mill (manufactured by Kotobuki Co., Ltd.: Ultra Aspek Mill UAM-015) using zirconia beads having a diameter of 0.3 mm for 1 hour, and the beads were then sieved to obtain a polyvalent metal compound dispersion liquid (z-3) having a solid content concentration of 31.0%.

[0114] (Preparation of Coating Agent (b-1) for (Layer B)) 68.32 parts of water, 18.7 parts of isopropyl alcohol (IPA, manufactured by Taishin Chemical Co., Ltd.), 10.7 parts of an aqueous solution of ammonium polyacrylate (A-30, manufactured by Toagosei Co., Ltd., solids content 31%) having a weight average molecular weight of 720,000 and a pH of 7.7, and 2.28 parts of a polyvalent metal compound dispersion (z-1) were added and stirred for 1 hour to obtain a coating agent (b-1). At this time, the compounding equivalent of ZnO (polyvalent metal compound) relative to the carboxyl groups of the ammonium salt of a resin having carboxyl groups (ammonium polyacrylate salt) was 0.45. Furthermore, the mixing ratio of a resin (P1) having a weight average molecular weight of 3,000 to 200,000 and a resin (P2) having a weight average molecular weight of 200,000 to 10,000,000 was P2 / P1 = 97.

[0115] (Preparation of Coating Agents (b-2 to b-24) for (Layer B)) Coating agents (b-2 to b-24) were obtained by preparing in the same manner as b-1, except that the formulation of coating liquid (b-1) was changed as shown in Tables 1 to 4. The raw materials used in Tables 1 to 4 are as follows, with blank spaces indicating no formulation. Hydroxyl group-containing compound (glycerin, Kanto Chemical) Hydroxyl group-containing compound (ethylene glycol, Kanto Chemical) Hydroxyl group-containing compound (Surfynol 104PA, Nissin Chemical Industry) Hydroxyl group-containing compound (Surfynol 420, Nissin Chemical Industry) Ethanol-based mixed solvent (Solmix AP-1, Japan Alcohol Sales Co., Ltd.)

[0116]

[0117]

[0118]

[0119]

[0120] (Preparation of Coating Agent (h-1) for Comparative Example (Layer B)) 70.1 parts of water, 18.0 parts of isopropyl alcohol (IPA), 11.0 parts of an aqueous solution of ammonium polyacrylate (A-30, Toagosei Co., Ltd., solids content 31%) having a weight average molecular weight of 720,000 and a pH of 7.7, and 0.7 parts of glycerin were mixed, and the mixture was dispersed in a bead mill (Ultra Aspek Mill UAM-015, manufactured by Kotobuki Co., Ltd.) using zirconia beads having a diameter of 0.3 mm for 1 hour, and the beads were then sieved to obtain Coating Agent (h-1).

[0121] (Preparation of Coating Agents (h-2 to h-4) for Comparative Example (Layer B)) Coating agents (h-2 to h-4) were prepared in the same manner as for b-1, except that the formulation of the coating liquid (b-1) was changed as shown in Table 5.

[0122]

[0123] (Preparation of Gas Barrier Laminate) Any one of the coating agents (b-1) to (b-24) and (h-1) to (h-4) was applied onto the prepared (A) layer using bar coater #3, and the applied coating was dried for 1 minute in a hot air dryer set at 80°C to form a (B) layer, which was used as a gas barrier laminate.

[0124] (Preparation of Packaging Material) DiCdry LX-830 and KW-75 (both manufactured by DIC Corporation) were blended in a blending ratio of 10 / 1.5, and ethyl acetate was added to give a non-volatile content of 25% to obtain an adhesive. The adhesive was then applied to layer (B) of the prepared gas barrier laminate using a bar coater #8, and the dilution solvent was evaporated using a dryer set at a temperature of 50°C. The adhesive was then laminated to a non-oriented polypropylene film (CPP film, Toyobo Co., Ltd., P1128). Aging was carried out at 40°C for 3 days to obtain a packaging material [layer (A) (substrate: OPP film) / layer (B) / adhesive / CPP film].

[0125] The results are shown in Tables 6 to 10.

[0126]

[0127]

[0128]

[0129]

[0130]

[0131] In Examples 1 to 24, coating agents with good liquid stability were produced. On the other hand, Comparative Example 1, in which the carboxyl group-containing resin did not contain a resin (P1) with a weight-average molecular weight of 3,000 to 200,000 and was composed solely of a resin (P2) with a weight-average molecular weight of 200,000 to 10,000,000, exhibited poor liquid stability. Furthermore, Comparative Example 2, in which the P1:P2 ratio was not within the range of 1:10 to 1:2,000, exhibited poor liquid stability.

[0132] In Examples 1 to 24, gas barrier laminates having good gas barrier properties and gas barrier properties after the flex test were produced. On the other hand, in Comparative Examples 2 to 4, sufficient gas barrier properties and gas barrier properties after the flex test were not obtained. From the above results, it was confirmed that the gas barrier laminates and packaging materials having the configuration of the present invention have good gas barrier properties.

[0133] (Evaluation item 4: Retort processing test) A pouch measuring 210 mm in length and 150 mm in width was prepared using the gas barrier laminate, with three sides sealed, and filled with water. After that, a retort sterilization treatment was performed at 121°C for 30 minutes, and the pouch was visually inspected for peeling. (Evaluation criteria) ○: No peeling in the pouch △: Peeling in part of the pouch ×: Significant peeling in the pouch

[0134] (Preparation of Coating Agents (b-25 to b-31) for (Layer B)) Coating agents (b-25 to b-31) were prepared in the same manner as for b-1, except that the formulation of coating liquid (b-1) was changed as shown in Table 11. The raw materials used in Table 11 are as follows, and blank spaces indicate that no raw materials were used. Silicon compound acetone diluted solution (KBM-6803, Shin-Etsu Chemical Co., Ltd.) Silicon compound acetone diluted solution (KBE-903, Shin-Etsu Chemical Co., Ltd.)

[0135]

[0136] (Preparation of Gas Barrier Laminate) Any one of the coating agents (b-25) to (b-31) was applied onto the prepared (A) layer using bar coater #3, and the applied coating was dried for 1 minute in a hot air dryer set at 80°C to form a (B) layer, which was used as a gas barrier laminate.

[0137] (Preparation of Packaging Material) DiCdry LX-703VL and KR-90 (both manufactured by DIC) were blended in a blending ratio of 15 / 1, and ethyl acetate was added so that the nonvolatile content was 25% to obtain an adhesive. The adhesive was then applied to layer (B) of the prepared gas barrier laminate using a bar coater #8, and the dilution solvent was evaporated using a dryer set at a temperature of 50°C. The adhesive was then laminated to a non-oriented polypropylene film (CPP film ZK207, manufactured by Toray Advanced Film). Aging was carried out at 40°C for 3 days to obtain a packaging material [layer (A) (substrate: OPP film) / layer (B) / adhesive / CPP film].

[0138] The results are shown in Table 12.

[0139]

[0140] In Examples 25 to 31, gas barrier laminates were produced that had good gas barrier properties, gas barrier properties after a flex test, and pouch appearance after retort. These results confirmed that the gas barrier laminates and packaging materials having the configuration of the present invention have good gas barrier properties and retort resistance.

Claims

1. A gas barrier laminate comprising: (A) layer (A) made of an olefin-based base material having an inorganic layer formed on at least one surface thereof; and (B) layer (B) containing an ammonium salt of a resin having a carboxyl group, and 0.1 to 0.5 chemical equivalents of a polyvalent metal compound relative to the carboxyl group of the ammonium salt of the resin having a carboxyl group, wherein the (B) layer contains an ammonium salt of a resin (P1) having a carboxyl group and a weight average molecular weight of 3,000 to 200,000, and an ammonium salt of a resin (P2) having a carboxyl group and a weight average molecular weight of 200,000 to 10,000,000, in a range of P2 / P1 = 10 to 2000.

2. The gas barrier laminate according to claim 1, wherein the layer (B) contains a hydroxyl group-containing compound having a boiling point of 120° C. or higher in an amount of 0.04 to 15% by mass based on the solid content of the layer (B).

3. The gas barrier laminate according to claim 1, wherein the layer (B) contains 10 to 30 mass % of at least one compound (S) selected from the group consisting of silicon compounds represented by general formula (s1) and hydrolysates thereof. (R １ O) ３ Si-(CH ２ ) ｎ -R ２ ...(s1) (In general formula (s1), R １ represents an alkyl group, R ２ represents an organic group having an epoxy group or an amino group, and n represents an integer of 1 to 10.

4. The gas barrier laminate according to claim 1, wherein the inorganic layer in the layer (A) is formed by either a vapor deposition treatment or a sputtering treatment.

5. The gas barrier laminate according to claim 1, wherein the inorganic layer in the layer (A) is formed from one or more inorganic substances selected from the group consisting of aluminum oxide, silicon oxide, aluminum, zinc oxide and magnesium oxide.

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

7. A packaging material comprising the gas barrier laminate according to any one of claims 1 to 5 and a second substrate laminated together with an adhesive.