Laminates and packaging materials

Abstract

Provided are a gas barrier laminate and a packaging material that have high gas barrier properties and reduce the risk of isocyanate monomers remaining in the adhesive layer. 【Solution means】A laminate comprising a first substrate, a gas barrier resin layer, a solvent-free adhesive layer, and a second substrate, wherein the gas barrier resin layer is (A1) or (A2), and the isocyanate monomer in the solvent-free adhesive layer is less than 0.1%. (1) A water-soluble polymer having a hydroxyl group and a silicon compound represented by Si(OR 1 )4, or R 2 Si(OR 3 )3 (where OR 1 and OR 3 represent hydrolyzable groups, and R 2 represents an organic functional group), or a hydrolyzate of the silicon compound, containing one or more of them, as the gas barrier resin layer (A1) (2) A gas barrier resin layer (A2) containing a heteroatom compound having dehydrative condensation properties and a polymer having a carboxyl group

Description

[Technical Field]

[0001] This invention relates to laminates and packaging materials. [Background technology]

[0002] Gas barrier materials are used in various fields to prevent the intrusion of gases such as moisture and oxygen from the outside air. For example, packaging materials used for food and beverages require oxygen barrier properties to prevent the intrusion of oxygen from the outside in order to suppress oxidation, as well as carbon dioxide barrier properties and barrier functions against various aroma components, in order to protect the contents from various distribution, storage such as refrigeration, and processing such as heat sterilization, and for the purpose of long-term food preservation. In addition, various displays such as solar cells, liquid crystals, organic or inorganic electroluminescence (hereinafter referred to as "EL"), and electronic devices such as electronic paper generally use glass substrates as sealing materials to protect their internal structure and block oxygen and water vapor from the outside. However, in order to provide thinner, lighter, or more flexible products, the use of transparent gas barrier films based on plastic films is being considered (see, for example, Patent Documents 1 and 2).

[0003] Recently, packaging materials and sealants are required to be recyclable at the time of disposal. Conventionally, methods for providing gas barrier properties have generally involved using aluminum foil or aluminum vapor-deposited films as part of the composition. However, since aluminum reduces recyclability, there is a demand for gas barrier materials that do not use aluminum.

[0004] On the other hand, conventionally, solvent-free urethane reactive two-component adhesives (hereinafter sometimes referred to as two-component curing adhesives or reactive adhesives) have been widely used as adhesives when laminating laminates used in such packaging materials. Since urethane reactive two-component curing adhesives use isocyanate prepolymers as curing components, residual isocyanate monomers in the adhesive layer have become a problem. In particular, in recent years, considering the impact on human health and the environment, it has been decided that the handling conditions for isocyanate monomers will be strengthened by various regulations. Therefore, it is required to reduce as much as possible the residual isocyanate monomers in the adhesive layer and the amine monomers produced when isocyanate monomers react with moisture, and polyisocyanates suitable for this purpose are also being investigated. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2005-077553 [Patent Document 2] Japanese Patent Publication No. 2010-253861 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] The present invention aims to provide a gas barrier laminate and packaging material that has high gas barrier properties without containing aluminum foil or aluminum vapor-deposited film, and that reduces the risk of isocyanate monomers remaining in the adhesive layer. [Means for solving the problem]

[0007] In other words, the present invention provides a laminate comprising a first substrate, a gas barrier resin layer, a solvent-free adhesive layer, and a second substrate, wherein the gas barrier resin layer is (A1) or (A2), and the isocyanate monomer content in the solvent-free adhesive layer is less than 0.1%. (1) A water-soluble polymer having a hydroxyl group and Si(OR 1) 4. or R 2 Si(OR 3 )3 (where OR 1 and OR 3 represent hydrolyzable groups, and R 2 represents an organic functional group), a silicon compound represented by the formula, or a gas barrier resin layer (A1) containing one or more hydrolyzates of the silicon compound (2) A gas barrier resin layer (A2) containing a heteroatom compound having dehydrative condensability and a polymer having a carboxyl group

[0008] The present invention also provides a packaging material comprising the laminate described above [Effect of the Invention]

[0009] [[ID=Z3]]According to the present invention, a gas barrier laminate having high gas barrier properties without having an aluminum foil, an aluminum vapor deposition film, etc., and having a reduced risk of isocyanate monomer remaining in the adhesive layer can be obtained, and by using it, a packaging material that achieves both high gas barrier properties and safety at a high level can be obtained [Embodiments for Carrying Out the Invention]

[0010] In this specification, "~" means not less than the value before the description of "~" and not more than the value after the description of "~"

[0011] (First Base Material) The first base material used in the present invention is not particularly limited, and examples thereof include polyethylene terephthalate (PET) film, polystyrene film, polyamide film, nylon film, polyacrylonitrile film, polyethylene film (OPE: biaxially stretched polyethylene film, LLDPE: low density polyethylene film, HDPE: high density polyethylene film), polypropylene film (CPP: unstretched polypropylene film, OPP: biaxially stretched polypropylene film), etc., polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, cellophane, etc

[0012] Also, films laminated with inorganic vapor deposition layers such as metal oxides such as film silica and alumina can also be used. Specific examples include OPE films, OPP films, PET films, nylon films having a silica vapor deposition layer, OPE films, OPP films, PET films, nylon films having an alumina vapor deposition layer, and the like.

[0013] When being aware of a monomer material package, a film made of a thermoplastic resin mainly composed of an olefin resin can be used as the base material. Specific examples of the olefin resin include polyethylene such as low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear (linear) low-density polyethylene, polypropylene, ethylene-propylene copolymer, α-olefin polymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ethylene-acrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, cyclic olefin resin, ionomer resin, polyolefin resins such as polymethylpentene; and modified olefin resins obtained by modifying olefin resins with acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, and other unsaturated carboxylic acids.

[0014] Also, it is also preferable to use a film formed of a material containing a biomass-derived component as the film base material. Biomass films are sold by various companies, and for example, sheets such as those listed in the list of biomass-certified products described by the Japan Organic Resources Association, a general incorporated foundation, can be used.

[0015] A well-known example of a film made from biomass-derived ethylene glycol is derived from ethanol produced from biomass (biomass ethanol). For example, biomass-derived ethylene glycol can be obtained by conventionally known methods, such as a method that produces ethylene glycol via ethylene oxide from biomass ethanol. Alternatively, commercially available biomass ethylene glycol may be used; for example, the biomass ethylene glycol commercially available from India Glycol can be suitably used.

[0016] Alternatively, products using biomass raw materials, distinguished by their biomass plasticity as defined by ISO 16620 or ASTM D6866, are also available. Radioactive carbon-14C exists in the atmosphere at a rate of 1 in 10¹² atoms, and this rate does not change even in atmospheric carbon dioxide. Therefore, this rate does not change in plants that fix carbon dioxide through photosynthesis. For this reason, the carbon in plant-derived resins contains radioactive carbon-14C. In contrast, the carbon in fossil fuel-derived resins contains almost no radioactive carbon-14C. Therefore, by measuring the concentration of radioactive carbon-14C in the resin using an accelerator mass spectrometer, the proportion of plant-derived resin in the resin, i.e., the biomass plasticity, can be determined. Examples of plant-derived low-density polyethylene (PPE) biomass plastics with a biomass plastic content of 80% or more, preferably 90% or more, as defined by ISO 16620 or ASTM D6866, include Braskem's product names "SBC818," "SPB608," "SBF0323HC," "STN7006," "SEB853," and "SPB681," and films made from these materials can be suitably used.

[0017] For example, as an alternative to conventional polyolefin films using petroleum-based raw materials, biomass polyolefin films such as biomass polyethylene films and biomass polyethylene-polypropylene films, which contain polyethylene resin made from biomass-derived ethylene glycol, are also known. The polyethylene resin is not particularly limited except for the use of biomass-derived ethylene glycol as part of the raw materials. Examples include ethylene homopolymers and copolymers of ethylene and α-olefins with ethylene as the main component (ethylene-α-olefin copolymers containing 90% by mass or more of ethylene units). These can be used individually or in combination of two or more types. The α-olefin constituting the copolymer of ethylene and α-olefin is not particularly limited, and examples include α-olefins having 4 to 8 carbon atoms, such as 1-butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. Known polyethylene resins such as low-density polyethylene resin, medium-density polyethylene resin, and linear low-density polyethylene resin can be used. Among these, linear low-density polyethylene resin (LLDPE) (a copolymer of ethylene and 1-hexene, or a copolymer of ethylene and 1-octene) is preferred, and linear low-density polyethylene resin with a density of 0.910 to 0.925 g / cm3 is more preferred, from the viewpoint of making it even less likely for damage such as punctures or tears to occur when the films rub against each other.

[0018] The biomass film may be a laminate formed by stacking multiple biomass films, or it may be a laminate formed by combining a conventional petroleum-based film with a biomass film.

[0019] The substrate may be subjected to some kind of surface treatment, such as physical treatments like corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen gas or nitrogen gas, glow discharge treatment, or flame treatment, or chemical treatments such as oxidation treatment using chemicals, or other treatments.

[0020] The aforementioned substrate can be manufactured using conventionally known film-forming methods such as extrusion, casting, T-die, cutting, and inflation methods. It may be an unstretched film, or, from the viewpoint of strength, dimensional stability, and heat resistance of the film (1), it may be stretched in one or two axes using a tenter method, tubular method, or the like.

[0021] The aforementioned substrate may contain additives as needed. Specifically, plastic compounding agents and additives such as elastomers, lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, and pigments may be added for the purpose of improving or modifying properties such as processability, heat resistance, weather resistance, mechanical properties, dimensional stability, oxidation resistance, slipperiness, mold release properties, flame retardancy, mold resistance, electrical properties, and strength. The amount of additives added should be adjusted within a range that does not affect other properties or recyclability.

[0022] The film thickness of the substrate is not particularly limited and can be appropriately selected within the range of 0.1 to 300 μm from the viewpoint of moldability and transparency. Preferably, it is in the range of 0.3 to 100 μm. If it is less than 0.1 μm, the strength will be insufficient, and if it exceeds 300 μm, the rigidity will be too high, which may make processing difficult.

[0023] From a recycling perspective, it is preferable to keep the layer structure as simple as possible. However, from the perspective of distribution of packaging materials, printing to indicate the contents of the packaging material, product description, and name is often necessary. The base material is also often printed on.

[0024] (Printing layer) The printed layer is a layer on which characters, figures, symbols, or other desired patterns are printed. The printing method and ink are not particularly limited; known printing methods and inks can be used. The films used as the substrate often employ printing inks produced by gravure printing, flexographic printing, offset lithography, and inkjet printing. Printing inks combining these methods with curing methods using active energy rays such as ultraviolet (UV), LEDs, or electron beams (EB), or by heat, are also used. Depending on the solvent used, inks may also be referred to as water-based inks or organic solvent-based inks.

[0025] Specifically, these include gravure printing inks and flexographic printing inks (in some industries, gravure printing inks and flexographic printing inks are referred to as liquid inks), UV-curable inks for lithographic offset printing, electron beam-curable inks for lithographic offset printing, UV-curable inks for inkjet recording printing, and electron beam-curable inks for inkjet recording printing.

[0026] The position in which the printed layer printed using these inks is provided is arbitrary; it may be provided on the first substrate, or a separate substrate on which the printed layer is provided may be one of the components of the laminate of the present invention, and the position is arbitrary. Furthermore, 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 and substantially does not contain a colorant. The following describes the liquid inks most commonly used for printing on film.

[0027] The resins used in liquid inks are not particularly limited and include, for example, acrylic resins, polyester resins, styrene resins, styrene-maleic acid resins, maleic acid resins, polyamide resins, polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-acrylic copolymer resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, polyvinyl chloride resins, chlorinated polypropylene resins, cellulose resins, epoxy resins, alkyd resins, rosin resins, rosin-modified maleic acid resins, ketone resins, cycloplastic rubbers, chlorinated rubbers, butyral, petroleum resins, etc., and one or more of these can be used in combination. Preferably, at least one or more selected from polyurethane resins, vinyl chloride-vinyl acetate copolymer resins, and cellulose resins are used.

[0028] Examples of colorants used in liquid inks include inorganic pigments such as titanium dioxide, 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.

[0029] Liquid inks for film printing are often organic solvent-based inks. Preferably, the organic solvent used does not contain aromatic hydrocarbon-based organic solvents. More specifically, 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. One or more of these can be used in combination.

[0030] (Gas barrier resin layer) The gas barrier resin layer used in the present invention is characterized by being (A1) or (A2). (1) A water-soluble polymer having a hydroxyl group, and a silicon compound represented by Si(OR 1 )4, or R 2 Si(OR[[ID=�]] 3 )3 (where OR 1 and OR 3 represent hydrolyzable groups, and R 2 represents an organic functional group), or a gas barrier resin layer (A1) containing one or more of the hydrolyzates of the silicon compound (2) A gas barrier resin layer (A2) containing a heteroatom compound having dehydrative condensability and a polymer having a carboxyl group

[0031] (Gas barrier resin layer (A1)) The gas barrier resin layer (A1) used in the present invention contains a water-soluble polymer having a hydroxyl group. Examples of the water-soluble polymer having a hydroxyl group include vinyl alcohol-based polymers, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, sodium alginate, and the like. Among them, a vinyl alcohol-based polymer is preferably used because it can impart good gas barrier properties.

[0032] The vinyl alcohol-based polymer is a hydrolyzate of a homopolymer or copolymer of vinyl ester (a1) and can be obtained by a known and commonly used method. Alternatively, the vinyl alcohol-based polymer can be a reaction product of a hydrolyzate of a homopolymer or copolymer of vinyl ester (a1) and an aldehyde and can be obtained by a known and commonly used method.

[0033] Examples of vinyl esters (a1) include vinyl formate, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versatate, vinyl caproate, vinyl caprylate, vinyl laurylate, vinyl palmitate, vinyl stearate, vinyl oleate, and vinyl benzoate, and one or more of these can be used in combination. Vinyl acetate is preferred.

[0034] Polymerizable compounds (a2) copolymerizable with vinyl ester (a1) include ethylene, propene, 1-butene, isobutylene, 1,3-butadiene, isopropenyl acetate, 2-propenyl acetate, styrene, α-methylstyrene, vinyl chloride, acrylonitrile, maleic anhydride, methyl acrylate, methyl methacrylate, N-vinyl-N-methylformamide, vinylacetamide, N-vinylformamide, N-(hydroxymethyl)-N-vinylformamide, hydroxyethyl acrylate, methyl vinyl ketone, and diacetone acrylamide, and can be used individually or in combination of two or more. Among these, ethylene, isopropenyl acetate, and 2-propenyl acetate are preferred.

[0035] When vinyl ester (a1) and polymerizable compound (a2) are used in combination, the amounts used can be adjusted as appropriate. However, from the viewpoint of gas barrier properties, it is preferable to limit the amount of polymerizable compound (a2) to 60 mol% or less of the total amount of vinyl ester (a1) and polymerizable compound (a2), and more preferably to 25 mol% or less.

[0036] The degree of polymerization of the vinyl ester polymer, which is a precursor of the vinyl alcohol polymer, is not particularly limited, but is typically 500 to 10000, more preferably 800 to 6000, and more preferably 1000 to 3000. This allows for the creation of a coating agent with an excellent balance of gas barrier properties and coating suitability.

[0037] Aldehydes used in acetalization include aliphatic aldehydes such as formaldehyde, acetaldehyde, propylaldehyde, butyraldehyde, octylaldehyde, and dodecylaldehyde; alicyclic aldehydes such as cyclohexanecarbaldehyde; aromatic aldehydes such as benzaldehyde, naphthaldehyde, anthraldehyde, phenylacetaldehyde, tolualdehyde, dimethylbenzaldehyde, cuminaldehyde, and benzylaldehyde; and cyclohexenealdehyde, dimethylcyclohexenealdehyde, and acro Examples include unsaturated aldehydes such as lein; heterocyclic aldehydes such as furfural and 5-methylfurfural; hemiacetals such as glucose and glucosamine; and aldehydes containing an amino group such as 4-aminobutyraldehyde. In addition, one or more types of aliphatic ketones such as 2-propanone, methyl ethyl ketone, 3-pentanone, and 2-hexanone; alicyclic ketones such as cyclopentanone and cyclohexanone; and aromatic ketones such as acetophenone and benzophenone can be used.

[0038] Conventional known organic acids and inorganic acids such as acetic acid, p-toluenesulfonic acid, nitric acid, sulfuric acid, and hydrochloric acid can be used as acid catalysts during acetalization.

[0039] Suitable examples of vinyl alcohol polymers include polyvinyl alcohol, ethylene vinyl alcohol, and polyvinyl butyral. They may be used individually or in combination of two or more. From the viewpoint of balancing gas barrier properties and adhesion, it is more preferable to use either or both polyvinyl alcohol and ethylene vinyl alcohol in combination.

[0040] The gas barrier resin layer (A1) used in this invention is Si(OR 1 )4, or R 2 Si(OR 3 )3(However OR 1 and OR 3 represents a hydrolyzable group, R 2It contains a silicon compound represented by (where represents an organic functional group), or a hydrolysate of the said silicon compound. Examples of these silicon compounds, or hydrolysates thereof, include tetraalkoxysilanes such as tetraethyl silicate (Si(OC2H5)4) (hereinafter sometimes referred to as TEOS) and tetramethyl silicate; trialkoxysilanes such as trimethoxymethylsilane, triethoxymethylsilane, and trimethoxyvinylsilane; dialkoxysilanes such as dimethoxydimethylsilane and diethoxydimethylsilane; monoalkoxysilanes such as methoxytrimethylsilane and ethoxytrimethylsilane, or their hydrolysates or partial hydrolysates.

[0041] TEOS is preferred because it is relatively stable in aqueous solvents after hydrolysis. 2 Si(OR 3 )3 contains R 2 The group is preferably a vinyl group, epoxy group, acryloyl group, methacryloxy group, ureido group, or isocyanate group.

[0042] When the water-soluble polymer is a vinyl alcohol-based polymer, the ratio of the mass of the vinyl alcohol-based polymer to the mass of the total solids in the mixed solution is preferably 20% by mass or more and 50% by mass or less, and more preferably 25% by mass or more and 40% by mass or less. The inclusion of 20% by mass or more of PVA maintains the flexibility of the coating film. Therefore, the formation of the coating film is easy. Furthermore, the inclusion of 50% by mass or less of the vinyl alcohol-based polymer makes it possible to have sufficient barrier properties.

[0043] The gas barrier resin layer (A1) may contain other components besides the hydroxyl-containing water-soluble polymer or the silicon compound or hydrolysate of the silicon compound. Other components may include other water-soluble polymers (e.g., sodium polyacrylate, polyethylene oxide, polyvinylpyrrolidone, dextrin, chitosan, chitin, methylcellulose, hydroxyethylcellulose, etc.), fragrances, rust inhibitors, colorants, fillers, defoamers, UV absorbers, fluorescent whitening agents, liquid paraffins, bitter components (e.g., denatonium benzoate, etc.).

[0044] The gas barrier resin layer (A1) can be formed by known methods without particular limitations, but the easiest method is to apply a coating liquid (A1) (hereinafter sometimes simply referred to as coating liquid (A1)) containing the hydroxyl group-containing water-soluble polymer and one or more silicon compounds or hydrolyzed products of silicon compounds to the first substrate using a known coating method to form a coating film. For example, coating methods such as spray coating, spin coating, dip coating, roll coating, blade coating, doctor roll coating, doctor blade coating, curtain coating, slit coating, screen printing, inkjet coating, dispensing, die coating, direct gravure, reverse gravure, flexographic coating, knife coating, and dot coating can be used.

[0045] (Water-based solvent) To facilitate coating, the coating solution (A1) preferably contains any aqueous solvent. As an aqueous solvent, water, water-soluble organic solvents that dissolve in water, etc., can be used. As water, pure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, or ultrapure water can be used. From the viewpoint of long-term storage, it is preferable to use water that has been sterilized by ultraviolet irradiation or hydrogen peroxide addition, as this can prevent the growth of mold or bacteria.

[0046] Examples of water-soluble organic solvents include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, and hexanediol; glycol esters such as propylene glycol laurate; diethylene glycol ethers such as diethylene glycol monoethyl, diethylene glycol monobutyl, diethylene glycol monohexyl, and carbitol; glycol ethers such as cellosolve containing propylene glycol ether, dipropylene glycol ether, and triethylene glycol ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, butyl alcohol, and pentyl alcohol; and various other solvents known as aqueous organic solvents, such as sulfolanes, esters, ketones, lactones such as γ-butyrolactone, lactams such as N-(2-hydroxyethyl)pyrrolidone, glycerin, and its polyalkylene oxide adducts. These aqueous organic solvents can be used individually or in combination of two or more.

[0047] The thickness of the gas barrier resin layer (A1) is preferably selected from a range of, for example, 0.05 μm to 30 μm.

[0048] (Gas barrier resin layer (A2)) The gas barrier resin layer (A2) used in the present invention contains a heteroatom compound having dehydration condensation properties and a polymer having a carboxyl group.

[0049] (Heteroatom compounds with dehydration condensation properties) The heteroatom compounds having dehydration condensation properties used in this invention are compounds that undergo dehydration condensation when in contact with compounds having a hydroxyl group, and which have a heteroatom in their structure. Examples of these heteroatom compounds having dehydration condensation properties include phosphoric acid, sulfuric acid, and nitric acid. These phosphoric acid, sulfuric acid, and nitric acid may be used individually or in combination.

[0050] The amount of the heteroatom compound having dehydration condensation properties added is not particularly limited as long as the effects of the present invention can be obtained, but it is preferably included in the gas barrier resin layer (A2) in an amount of 10 parts by mass or less, and is particularly preferred when included in an amount of 4 to 6 parts by mass, as this further improves adhesion when in contact with compounds having hydroxyl groups in the composition.

[0051] (A polymer containing a carboxyl group) The polymer having a carboxyl group used in the present invention is a polymer that uses a polymerizable unsaturated monomer having a carboxyl group in its structure (hereinafter, "polymerizable unsaturated monomer" is referred to as "monomer") as a polymerization raw material. Specific examples of monomers having a carboxyl group in their structure include (meth)acrylic acid and β-carboxyethyl (meth)acrylic acid, with (meth)acrylic acid being preferred. Furthermore, the carboxyl group in the present invention may include a structure in which an H2O molecule has been lost from two molecules of carboxylic acid, such as a carboxylic anhydride. In the present invention, "(meth)acrylic acid" refers to either or both acrylic acid and methacrylic acid, and "(meth)acrylate" refers to either or both acrylate and methacrylate.

[0052] The acid value of the polymer having the carboxyl group is not particularly limited within the range in which the effects of the present invention can be obtained, but an acid value of 50 to 800 mgKOH / g is preferable because it improves barrier performance. Furthermore, an acid value of 80 to 800 mgKOH / g is more preferable, and if the acid value is 80 mgKOH / g or higher, ionic bonding proceeds sufficiently and high barrier performance can be obtained.

[0053] (Method for measuring acid value) The acid value is the amount of potassium hydroxide (in mg) required to neutralize the acid present in 1 g of a sample. Specifically, it can be measured by dissolving the weighed sample in a suitable solvent, for example, a solvent with a volume ratio of toluene / methanol = 70 / 30, adding a few drops of 1% phenolphthalein alcohol solution, and then adding 0.1 mol / L potassium hydroxide alcohol solution dropwise and observing the point of color change. The acid value can then be calculated using the following formula.

[0054] (Method for measuring acid value - 1) Acid value (mgKOH / g)=(V×F×5.61) / S V: Amount of 0.1 mol / L potassium hydroxide alcohol solution used (mL) F: Titer of 0.1 mol / L potassium hydroxide alcohol solution S: Sample volume (g) 5.61: Amount of potassium hydroxide equivalent (mg) in 1 mL of 0.1 mol / L potassium hydroxide alcohol solution

[0055] If the sample is a resin solution, the resin acid value (mgKOH / g) can be calculated using the following formula.

[0056] Resin acid value (mgKOH / g) = Acid value of resin solution (mgKOH / g) / NV (%) × 100 NV: Non-volatile content (%)

[0057] Furthermore, if the solubility of the sample in an organic solvent is low and precipitation occurs, making measurement difficult, the acid value can also be measured using the following method.

[0058] (Acid value measurement method - 2) The acid value (mgKOH / g-resin) is calculated using the following formula, employing an FT-IR (JASCO Corporation, FT-IR4200), the coefficient (f) obtained from a calibration curve prepared with a chloroform solution of maleic anhydride, the absorbance (I) of the stretching peak of the anhydride ring of maleic anhydride (1780 cm-1) and the absorbance (II) of the stretching peak of the carbonyl group of maleic acid (1720 cm-1) in a maleic anhydride-modified polyolefin solution. Acid value (mgKOH / g-regin) = [(Absorbance (I) × (f) × 2 × Molecular weight of potassium hydroxide × 1000 (mg) + Absorbance (II) × (f) × Molecular weight of potassium hydroxide × 1000 (mg)) / Molecular weight of maleic anhydride] Molecular weight of maleic anhydride: 98.06, molecular weight of potassium hydroxide: 56.11

[0059] The carboxyl group polymer used in this invention is not particularly limited in terms of molecular weight, but a weight-average molecular weight of 300 to 1,000,000 is preferred from the viewpoint of good film formation properties. Particularly preferred is 500 to 500,000. The weight-average molecular weight of the carboxyl group polymer used in this invention can be calculated by measuring it using gel permeation chromatography (GPC).

[0060] The polymer having a carboxyl group is not particularly limited in its resin skeleton within the range in which the effects of the present invention can be obtained. It may be a homopolymer of polymerizable unsaturated monomers having a carboxyl group, or a copolymer using multiple polymerizable unsaturated monomers having a carboxyl group. It may also be a copolymer of a polymerizable unsaturated monomer having a carboxyl group with other monomers that can be copolymerized. In the present invention, it is preferable to use one or more polymers selected from the group consisting of acrylic acid, methacrylic acid, maleic acid, and itaconic acid as the polymer having a carboxyl group.

[0061] ((meth)acrylic acid polymer) The (meth)acrylic acid polymer can be any polymer of (meth)acrylic acid monomer, such as ethylene glycol di(meth)acrylate, polyethylene glycol (meth)acrylates, ethylene oxide-modified 4,4-dihydroxydiphenyl sulfone di(meth)acrylate, ethylene oxide-modified bisphenol A di(meth)acrylate and other polyethers, ethylene glycol diglycidyl di(meth)acrylate, ethylene oxide-modified bisphenol A diglycidyl di(meth)acrylate, etc.

[0062] (Carboxyl group-containing vinyl polymer) Examples of carboxyl group-containing vinyl polymer resins include polymers of polymerizable unsaturated monomers having carboxyl groups. Examples of polymerizable unsaturated monomers having carboxyl groups include unsaturated carboxylic acids such as (meth)acrylic acid, 2-carboxyethyl (meth)acrylate, crotonic acid, itaconic acid, maleic acid, or fumaric acid; Monoesters (half-esters) of various unsaturated dicarboxylic acids such as monomethyl itaconate, mono-n-butyl itaconate, monomethyl maleate, mono-n-butyl maleate, monomethyl fumarate, and mono-n-butyl fumarate, and saturated monohydric alcohols; Monovinyl esters of various saturated dicarboxylic acids, such as monovinyl adipic acid or monovinyl succinate; Examples include addition reaction products between various saturated polycarboxylic acid anhydrides such as succinic anhydride, glutaric anhydride, phthalic anhydride, or trimellitic anhydride and various hydroxyl group-containing vinyl monomers; and various monomers obtained by addition reactions between the aforementioned carboxyl group-containing monomers and lactones.

[0063] Examples of monomers copolymerizable with the polymerizable unsaturated monomer having a carboxyl group include the following:

[0064] (Meth)acrylic acid esters having alkyl groups with 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, hepcyl (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;

[0065] (meth)acrylic acid esters having an alkaline alkyl group such as cyclohexyl (meth)acrylate, isobolonyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and dicyclopentenyloxyethyl (meth)acrylate; (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; hydroxyethyl (meth)acrylate; hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, and glycerol (meth)acrylate; acrylic acid esters having a hydroxyalkyl group such as lactone-modified hydroxyethyl (meth)acrylate, polyethylene glycol (meth)acrylate, and polypropylene glycol (meth)acrylate;

[0066] 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; styrene derivatives such as styrene, α-methylstyrene, and chlorostyrene; diene compounds such as butadiene, isoprene, piperine, and dimethylbutadiene; vinyl halides and vinylidenes such as vinyl chloride and vinyl bromide; unsaturated ketones such as methyl vinyl ketone and butyl vinyl ketone; vinyl esters such as vinyl acetate and vinyl butyrate; vinyl ethers such as methyl vinyl ether and butyl vinyl ether; vinyl cyanides such as acrylonitrile, methacrylonitrile, and vinylidene cyanide; acrylamide and its alkyd-substituted amides; N-substituted maleimides such as N-phenylmaleimide and N-cyclohexylmaleimide;

[0067] Fluorine-containing α-olefins such as vinyl fluoride, vinylidene fluoride, trifluoroethylene, chlorotrifluoroethylene, bromotrifluoroethylene, pentafluoropropylene, or hexafluoropropylene; or (per)fluoroalkyl / perfluorovinyl ethers having 1 to 18 carbon atoms in the (per)fluoroalkyl group, such as trifluoromethyltrifluorovinyl ether, pentafluoroethyltrifluorovinyl ether, or heptafluoropropyltrifluorovinyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,3,3-tetrafluoropropyl (meth)acrylate, 1H,1H,5H-octafluoro Examples include fluorine-containing ethylenically unsaturated monomers such as pentyl (meth)acrylate, 1H,1H,2H,2H-heptadecafluorodecyl (meth)acrylate, or perfluoroethyloxyethyl (meth)acrylate, which have 1 to 18 carbon atoms in the (per)fluoroalkyl group; silyl group-containing (meth)acrylates such as γ-methacryloxypropyltrimethoxysilane; and N,N-dialkylaminoalkyl (meth)acrylates such as N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, or N,N-diethylaminopropyl (meth)acrylate.

[0068] The polymer having the carboxyl group can be obtained by polymerization or copolymerization using known methods, and the polymerization form is not particularly limited. It can also be produced by addition polymerization in the presence of a catalyst (polymerization initiator), and may be a polymer of any type, such as a random copolymer, block copolymer, or graft copolymer. Known polymerization methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can also be used for copolymerization.

[0069] The gas barrier resin layer (A2) may contain compounds other than heteroatom compounds and polymers having carboxyl groups that exhibit dehydration condensation properties, to the extent that the effects of the present invention can be obtained. These additional additives may include alcohols such as methanol, ethanol, propanol, butanol, and hexanol; solvents such as ethylene glycol, propylene glycol, and glycerin; coupling agents; silane compounds; phosphoric acid 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.

[0070] The gas barrier resin layer (A2) can be formed in the same manner as the gas barrier resin layer (A1). The easiest method is to apply a coating liquid (A2) (hereinafter sometimes simply referred to as coating liquid (A2)) containing a heteroatom compound having dehydration condensation properties and a polymer having a carboxyl group to the first substrate using a known coating method to form a coating film. To facilitate coating, it is preferable that the coating liquid (A2) contains any organic solvent.

[0071] Furthermore, it is preferable that the gas barrier resin layer (A2) has an adjacent resin layer (A2-2) containing a polyvalent metal compound. Here, "adjacent" means that at least a portion of the resin layer (A) and the resin layer (A2-2) are in direct contact.

[0072] The polyvalent metal compound contained in the resin layer (A2-2) is a metal compound with a valency of 2 or higher, which is mixed with a water-soluble polymer to form the resin layer (A2-2). Examples of such polyvalent metal compounds include zinc compounds, magnesium compounds, calcium compounds, manganese compounds, iron compounds, cobalt compounds, nickel compounds, and copper compounds, with zinc compounds, magnesium compounds, and calcium compounds being particularly preferred. These metal compounds may be used individually or in combination of two or more.

[0073] The polyvalent metal compounds that may be used in the present invention are preferably divalent metal oxides, hydroxides, or carbonates, and mixtures thereof are also acceptable. Among these divalent metal compounds, zinc oxide, magnesium oxide, and calcium oxide are preferred, with zinc oxide and magnesium oxide being particularly preferred.

[0074] The polyvalent metal compound is preferably in particulate form. More preferably, it is a fine particle with an average particle diameter of 10 nm or more and 500 nm or less. Particularly preferably, it is a fine particle with a particle diameter of 20 nm to 300 nm. The average particle diameter here was measured using a dynamic light scattering particle size distribution analyzer, for example, the LB-500 (manufactured by Horiba, Ltd.).

[0075] These polyvalent metal compounds are preferably included in the resin layer (A2-2) containing the polyvalent metal compounds in an amount of 40 to 90 parts by mass, and are particularly preferred when included in an amount of 60 to 80 parts by mass, as this improves the gas barrier properties.

[0076] In addition to the polyvalent metal compound, a resin is added to the resin layer (A2-2) containing the polyvalent metal compound in order to stably coat the polyvalent metal compound. Specifically, examples include cellulose resins, ethyl cellulose resins, carboxymethyl cellulose resins, polyester resins, epoxy resins, acrylic resins, methacrylic resins, polyamide resins, polyether polyurethane polyol resins, polyester polyol resins, and polyurethane polyol resins. These resins may be used individually or in combination. Among these, ethyl cellulose resins, polyether polyurethane polyol resins, polyester polyol resins, and polyurethane polyol resins are preferred.

[0077] The aforementioned resin is preferably included in the resin layer (A2-2) containing the polyvalent metal compound in an amount of 10 to 60 parts by mass, and is particularly preferred when it is in the range of 20 to 40 parts by mass, as this results in good coating properties for the resin layer (A2-2).

[0078] Furthermore, it is preferable that the gas barrier resin layer (A2) has adjacent layers (A2-3) containing compounds selected from the group consisting of aluminum oxide, silicon oxide, and silicon nitride. In the present invention, the layers (A2-3) provided adjacent to the resin layer (A) are layers formed by depositing a compound selected from the group consisting of aluminum oxide, silicon oxide, and silicon nitride by processes such as vapor deposition, sputtering, and CVD. These (A2-3) layers may be formed on a base film such as polyethylene terephthalate (PET) resin film, polypropylene (PP) resin film, polybutylene terephthalate (PBT) resin film, nylon (NY) resin film, or biomass film. These base films may be films manufactured by various known processes such as biaxially oriented films, stretched films, or unstretched films, or films that have undergone various surface treatments as needed.

[0079] (The gas barrier resin layer (A2) is selected appropriately depending on the application, but the coating amount after drying is 0.01 to 100 g / m².) 2 Preferably, 0.1 to 50 g / m 2 More preferably, 0.5-3 g / m 2 That is particularly preferable.

[0080] (Second base material) The laminate comprising the first substrate and the gas barrier resin layer can also be bonded to a second substrate using an adhesive. Alternatively, the second substrate may be formed on the laminate by an extrusion method. The second base material may be the same type as the first base material or a different base material. When the laminate of the present invention is applied to a packaging material, assuming that the second base material is used as a sealant layer, the second base material can be selected as a polyolefin resin having heat-sealability. Examples include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), very low-density polyethylene (VLDPE), polypropylene (CPP), ethylene-propylene copolymer, and polymethylpentene, as well as ethylene copolymers such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ethylene-methyl acrylate (EMA) copolymer, ethylene-ethyl acrylate-maleic anhydride copolymer (E-EA-MAH), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylic acid copolymer (EMAA); further examples include ionomers of ethylene-acrylic acid copolymer and ionomers of ethylene-methacrylic acid copolymer, which may be used individually or in combination of two or more. When the second layer is a heat-seal layer, its film thickness can be adjusted as appropriate depending on the purpose, but from the viewpoint of aroma retention and heat sealability, it is typically 1 μm to 10 μm, and more preferably 3 μm to 10 μm.

[0081] (Solvent-free adhesive used for the bonding layer) When bonding the second layer to the laminate comprising the first substrate and the gas barrier resin layer, any solvent-free adhesive suitable for general lamination methods may be used. Examples of lamination methods include non-solvent lamination and extrusion lamination. The adhesive hardens and becomes the post-bonded layer.

[0082] As a solvent-free adhesive usable in the lamination method, a two-component curing adhesive consisting of a polyol and an isocyanate compound can be used. As a coating method for the lamination adhesive, for example, it can be applied by roll coating, direct gravure roll coating, gravure offset roll coating, kiss coating, reverse roll coating, fontein method, transfer roll coating, or other methods.

[0083] The present invention is characterized in that the isocyanate monomer content in the solvent-free adhesive layer is less than 0.1% by mass. In this case, the isocyanate compound used together with the polyol is preferably a polyisocyanate. A commercially available polyisocyanate with an isocyanate monomer content of less than 0.1% by mass can be used, and for example, the POLURGREEN series manufactured by Sapici SpA can be preferably used. Alternatively, a general-purpose polyisocyanate may be used, which has been adjusted to a concentration of less than 0.1% by mass relative to the solid content of the composition using existing removal techniques, such as a thin-film distillation apparatus.

[0084] In the aforementioned solvent-free adhesive, a functional adhesive may be used. For example, as a gas barrier adhesive, the PASLIM series of oxygen barrier adhesives manufactured by DIC Corporation, which is a two-component reactive adhesive consisting of a polyester polyol and an isocyanate compound, can be used. After the gas barrier adhesive hardens, it forms an adhesive layer. Using a gas barrier adhesive is preferable because it can further enhance the gas barrier properties of the laminate of the present invention.

[0085] The solvent-free adhesive coating method involves applying a solvent-free adhesive, preheated to approximately 40°C to 100°C, to one substrate using a roll such as a gravure roll, and then immediately bonding the other substrate 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.

[0086] For example, the application rate of solvent-free adhesive is 1 g / m². 2 More than 10g / m 2 Preferably 1 g / m 2 More than 5g / m 2 The following applies:

[0087] (Laminated structure) Herein are some examples of specific embodiments of the laminate of the present invention. Of course, the laminate of the present invention is not limited to these embodiments. The solvent-free adhesive layer is described as the adhesive layer. (Construction using two base materials) First substrate / Gas barrier resin layer / Adhesive layer / Second substrate First substrate / Printing layer / Gas barrier resin layer / Adhesive layer / Second substrate Printing layer / First substrate / Gas barrier resin layer / Adhesive layer / Second substrate First substrate / Gas barrier resin layer / Gas barrier adhesive layer / Second substrate First substrate / Printing layer / Gas barrier resin layer / Gas barrier adhesive layer / Second substrate Printing layer / First substrate / Gas barrier resin layer / Gas barrier adhesive layer / Second substrate

[0088] (Example 1 of a configuration using three base materials) First substrate / Gas barrier resin layer / Adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate First substrate / Printing layer / Gas barrier resin layer / Adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate Printing layer / First substrate / Gas barrier resin layer / Adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate First substrate / Gas barrier resin layer / Gas barrier adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate First substrate / Printing layer / Gas barrier resin layer / Gas barrier adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate Printing layer / First substrate / Gas barrier resin layer / Gas barrier adhesive layer / Substrate used as an intermediate layer / Adhesive layer / Second substrate

[0089] (Example 2 of a configuration using three base materials) The outermost layer refers to the substrate that comes into contact with the outside environment when three or more film substrates are used, after the packaging material has been formed through the lamination process. Outermost layer substrate / adhesive layer / gas barrier resin layer / first substrate / adhesive layer / second substrate Outermost layer substrate / Printing layer / Adhesive layer / Gas barrier resin layer / First substrate / Adhesive layer / Second substrate Printing layer / Substrate used as the outermost layer / Adhesive layer / Gas barrier resin layer / First substrate / Adhesive layer / Second substrate Outermost layer substrate / adhesive layer / gas barrier resin layer / first substrate / gas barrier adhesive layer / second substrate Outermost layer substrate / Printing layer / Adhesive layer / Gas barrier resin layer / First substrate / Gas barrier adhesive layer / Second substrate Printing layer / Substrate used as the outermost layer / Adhesive layer / Gas barrier resin layer / First substrate / Gas barrier adhesive layer / Second substrate

[0090] (packaging material) The laminate of the present invention can be used as a multilayer packaging material for the purpose of protecting food, pharmaceuticals, and other products. When used as a multilayer packaging material, the layer configuration may be changed depending on the contents, usage environment, and usage form. Furthermore, the packaging of the present invention may be appropriately provided with an easy-open treatment or resealing means.

[0091] As an example of the packaging material of the present invention, a laminate having a sealant layer is used. The sealant layer surfaces of the laminate are placed facing each other, and then the peripheral edges are heat-sealed to form a bag. As for the bag-making method, the laminate of the present invention can be folded or placed together so that the inner layer surfaces (sealant layer surfaces) face each other, and the peripheral edges can be heat-sealed in various forms such as side seal type, two-sided seal type, three-sided seal type, four-sided seal type, envelope seal type, gusset seal type, pleated seal type, flat-bottom seal type, square-bottom seal type, gusset type, and other heat-seal types. The packaging material of the present invention can take various forms depending on the contents, usage environment, and usage form. Self-standing packaging materials (standing pouches) are also possible. As for the heat-sealing method, known methods such as bar seal, rotary roll seal, belt seal, impulse seal, high-frequency seal, and ultrasonic seal can be used.

[0092] If the first and second substrates of the laminate of the present invention do not function as sealant layers that form heat-sealable areas when forming a packaging material, an additional sealant layer may be added. The sealant layer may be made by bonding additional substrates with the adhesive of the present invention, or it may be an adhesive layer made of the adhesive of the present invention.

[0093] Products using the packaging material of the present invention are manufactured by filling the packaging material with contents through its opening and then heat-sealing the opening. Examples of contents that can be filled include, for example, food products such as rice crackers, bean snacks, nuts, biscuits / cookies, wafers, marshmallows, pies, semi-baked cakes, candies, and snack foods; staple foods such as bread, instant noodles, dried noodles, pasta, aseptically packaged rice, rice porridge, packaged mochi, and cereal foods; processed agricultural products such as pickles, boiled beans, natto, miso, frozen tofu, tofu, enoki mushrooms, konjac, processed wild vegetables, jams, peanut cream, salads, frozen vegetables, and processed potato products; processed livestock products such as ham, bacon, sausages, processed chicken products, and corned beef; and fish ham. Examples of processed seafood products include sausages, processed seafood products, fish cakes, seaweed, preserved foods, dried bonito flakes, salted seafood, smoked salmon, and spicy cod roe; fruits such as peaches, oranges, pineapples, apples, pears, and cherries; vegetables such as corn, asparagus, mushrooms, onions, carrots, radishes, and potatoes; frozen and chilled prepared foods such as hamburgers, meatballs, fried seafood, dumplings, and croquettes; dairy products such as butter, margarine, cheese, cream, instant creamy powder, and infant formula; liquid seasonings; retort curry; and pet food.

[0094] Furthermore, as a non-food product, it can be used as a packaging material for various items such as cigarettes, disposable hand warmers, pharmaceuticals such as intravenous fluid packs, liquid laundry detergent, liquid dish soap, liquid bath detergent, liquid bath soap, liquid shampoo, liquid conditioner, cosmetics such as lotions and emulsions, vacuum insulation materials, and batteries. [Examples]

[0095] The present invention will be described in more detail below with reference to specific synthesis examples and embodiments, but the present invention is not limited to these embodiments. In the following examples, "parts" and "%" represent "parts by mass" and "mass%", respectively, unless otherwise specified.

[0096] <Manufacturing of the first base material> [Manufacturing Example 1] A PET film with a thickness of 12 μm was prepared, and the surface of the PET film on which the inorganic oxide deposition layer would be formed was subjected to plasma pretreatment. Subsequently, an aluminum oxide deposition film with a thickness of 15 nm was formed on the plasma-treated surface using a reactive resistance heating method as the heating means for a vacuum deposition method under the following conditions. This film is called AlOxPET. (Aluminum oxide film deposition conditions): Vacuum level: 8.1 × 10 -2 Pa

[0097] [Manufacturing Example 2] A 16 μm thick OPP film was prepared, and the surface of the OPP film on which the inorganic oxide deposition layer would be formed was subjected to plasma pretreatment. Subsequently, a 15 nm thick aluminum oxide deposition film was formed on the plasma-treated surface using a reactive resistance heating method as the heating means for vacuum deposition under the following conditions. This film is called AlOxOPP. (Aluminum oxide film deposition conditions): Vacuum level: 8.1 × 10 -2 Pa

[0098] For the outermost layer, we used Pylen P2161: 20μm, manufactured by Toyobo Co., Ltd. This film is called OPP.

[0099] For the intermediate layer, we used Embem ON: 25μm, manufactured by Unitika Ltd. This film is called OPA.

[0100] As the second substrate, we used Toray Film Processing Co., Ltd.'s Trefan ZK207: 70μm. This film is called CPP.

[0101] <Manufacturing of gas barrier resin layer C1> [Manufacturing Example 3] According to the compositions shown in Table 1, a mixture of composition (D) was prepared, and a hydrolysis solution of composition (E) prepared in advance was added and stirred to obtain a colorless, transparent gas barrier resin solution C1.

[0102] [Table 1]

[0103] <Manufacturing of gas barrier resin layer C2> [Manufacturing Example 4] 30 g of polyacrylic acid (Aron A-10H, manufactured by Toagosei Co., Ltd.) with a molecular weight of 200,000 was dissolved in isopropyl alcohol (hereinafter sometimes abbreviated as IPA) while stirring and boiling in a flask to obtain a polyacrylic acid solution with a solid content of 3%. To 100 g of this solution, 5 g of a phosphate IPA solution, obtained by diluting a concentrated phosphate aqueous solution (manufactured by Tokyo Chemical Industry Co., Ltd., solid content 86%) with IPA to a solid content of 5%, was added to obtain gas barrier resin solution C2.

[0104] [Manufacturing Example 5] 300 g of zinc oxide (hereinafter sometimes abbreviated as ZnO) with a primary particle size of 200 nm (manufactured by Sakai Chemical Industry Co., Ltd., FINEX-50) and 700 g of methyl ethyl ketone (hereinafter sometimes abbreviated as MEK) were mixed and dispersed for 1 hour using zirconia beads with a diameter of 0.3 mm in a bead mill (Kotobuki Chemical Co., Ltd., Ultra Aspec Mill UAM-015). The beads were then separated by sieving to obtain a ZnO solution with a solid content of 30%. The primary particle size of ZnO in this dispersion was 88 nm. This solution was mixed and stirred with a polyester resin solution (product name: Byron 500, manufactured by Toyobo Co., Ltd.) with a solid content of 5% (MEK dissolved in MEK) and a MEK solution to obtain a ZnO dispersion. The mixing ratio was ZnO solution: 20 g, polyester resin solution: 20 g, MEK: 60 g. A 200 ml beaker was first filled with polyester resin, MEK solution, and a stirring bar. The stirring bar was rotated at 200 rpm to confirm that the polyester resin and MEK were homogeneous. Then, the ZnO solution was added to obtain a ZnO dispersion. The solid content was 7%. The resulting gas barrier resin solution is called C3.

[0105] <Solvent-free adhesive layer> <Preparation of polyisocyanate component (X1)> For the solvent-free adhesive containing less than 0.1% isocyanate monomer, we used "POLURGREEN PRP940" from the POLURGREEN series manufactured by Sapici SpA. This isocyanate component is abbreviated as (X1).

[0106] <Preparation of isocyanate component (X2)> [Manufacturing Example 6] In a flask equipped with a stirrer, thermometer, and nitrogen gas inlet tube, 37.5 parts of 4,4-diphenylmethane diisocyanate (hereinafter abbreviated as "MDI") and 17.5 parts of 2,4'-MDI were charged into the reaction vessel, stirred under nitrogen gas, and heated to 60°C. 20.0 parts of a bifunctional PPG with a number average molecular weight of 400 and 25.0 parts of a bifunctional PPG with a number average molecular weight of 2000 were added dropwise in several portions, and the temperature was raised to 80°C and stirred for 5-6 hours to complete the urethane formation reaction. The isocyanate percentage of the obtained polyisocyanate was 13.2%, and the melt viscosity at 40°C was 1500 mPa.s. This polyisocyanate is abbreviated as (X2). The residual amount of isocyanate monomer in (X2) was 15%.

[0107] <Preparation of polyol component (Y1)> [Manufacturing Example 7] After purging the flask with nitrogen, 60.0 parts of castor oil and 40.0 parts of trifunctional compound PPG-3000 were added, stirred, and the mixture was heated to 80°C. After confirming that the two materials were thoroughly mixed, the flask was cooled to room temperature. This polyol component will be abbreviated as (Y1). The following chemicals were used for the above mixture. • Castor oil: Refined castor oil (manufactured by Ito Oil Co., Ltd., hydroxyl value 160.5 mgKOH / g, melt viscosity at 40℃ 250 mPa·s) • Trifunctional: PPG-3000: Actcol T-3000 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd., number average molecular weight approximately 3,000, hydroxyl value 56 mgKOH / g, melt viscosity at 40℃ 150 mPa·s)

[0108] <Fabrication of laminates> [Example 1] AlOxPET / Gas barrier resin layer C1 / Adhesive layer with less than 0.1% NCO monomer / OPA / Adhesive layer with less than 0.1% NCO monomer / CPP The gas barrier resin solution C1 prepared above was coated onto AlOxPET by direct gravure printing. Then, a gas barrier resin layer with a thickness of 300 nm (dry state) was formed by heat treatment at 85°C for 60 seconds. Next, a solvent-free adhesive mixed in a ratio of X1 / Y1 = 100 / 40 was applied to the barrier coat layer of the barrier film obtained above, and it was bonded to OPA. Furthermore, the resulting laminate was bonded to CPP using the same adhesive to obtain a laminate. The aging time for the adhesive in the laminate was 3 days at 40°C.

[0109] [Example 2] AlOxPET / Gas barrier resin layer C2 / Gas barrier resin layer C3 / Adhesive layer with less than 0.1% NCO monomer / OPA / Adhesive layer with less than 0.1% NCO monomer / CPP The gas barrier resin solution C2 prepared above was coated onto AlOxPET using the same method as in Example 1 and dried, and then the gas barrier resin solution C3 was coated onto it using the same method and dried. The subsequent procedure followed that of Example 1, and a laminate was obtained by bonding the layers with a solvent-free adhesive containing less than 0.1% isocyanate monomer, and then aged under the same conditions.

[0110] [Example 3] OPP / Adhesive layer with less than 0.1% NCO monomer / Gas barrier resin layer C1 / AlOxOPP / Adhesive layer with less than 0.1% NCO monomer / CPP The gas barrier resin solution C1 prepared above was coated onto AlOxOPP by direct gravure printing. Then, it was heat-treated at 85°C for 60 seconds to form a gas barrier resin layer with a thickness of 300 nm (dry state). Next, a solvent-free adhesive mixed in a ratio of X1 / Y1 = 100 / 40 was applied to the OPP and bonded to the side coated with the gas barrier resin layer. Furthermore, the side of the AlOxOPP film not coated with the gas barrier resin layer was bonded to CPP using the same adhesive to obtain a laminate, which was then aged under the same conditions.

[0111] [Example 4] OPP / Adhesive layer with less than 0.1% NCO monomer / Gas barrier resin layer C2 / Gas barrier resin layer C3 / AlOxOPP / Adhesive layer with less than 0.1% NCO monomer / CPP The gas barrier resin solution C2 prepared above was coated onto AlOxOPP using the same method as in Example 1 and dried, and then the gas barrier resin solution C3 was coated and dried using the same method. The subsequent procedure followed that of Example 3 to obtain a laminate bonded with a solvent-free adhesive containing less than 0.1% isocyanate monomer, and it was aged under the same conditions.

[0112] [Comparative Example 1] AlOxPET / adhesive layer / OPA / adhesive layer / CPP In Example 1, the gas barrier resin layer was not applied, and a solvent-free adhesive mixed in a ratio of X2 / Y1=100 / 80 was applied and bonded to the OPA. Furthermore, the resulting laminate was bonded to the CPP with the same adhesive to obtain a laminate, which was then aged under the same conditions.

[0113] [Comparative Example 2] AlOxPET / Gas Barrier Resin Layer C1 / Adhesive Layer / OPA / Adhesive Layer / CPP In Example 1, the adhesive was changed to a solvent-free adhesive mixed in a ratio of X2 / Y1=100 / 80, and a laminate was obtained by the same procedure and aged under the same conditions.

[0114] [Comparative Example 3] OPP / adhesive layer / AlOxOPP / adhesive layer / CPP In Example 3, the gas barrier resin layer was not applied, and a solvent-free adhesive mixed in a ratio of X2 / Y1=100 / 80 was applied and bonded to the OPP. Furthermore, the resulting laminate was bonded to the CPP with the same adhesive to obtain a laminate, which was then aged under the same conditions.

[0115] [Comparative Example 4] OPP / Adhesive layer / Gas barrier resin layer C1 / AlOxOPP / Adhesive layer / CPP In Example 1, the adhesive was changed to a solvent-free adhesive mixed in a ratio of X2 / Y1=100 / 80, and a laminate was obtained by the same procedure and aged under the same conditions.

[0116] (Measurement of oxygen permeability) For the laminates manufactured in the above examples and comparative examples, an oxygen permeability measuring device (MOCON, model name: OX-TRAN 2 / 21) was used, with the oxygen supply side facing the substrate layer surface of the barrier film. The measurement conditions were 23°C and a 90% RH atmosphere, and the oxygen permeability (cc / m³) was determined in accordance with the JIS K7126 method. 2 The following parameters (atm / day) were measured. The measurement results are shown in Table 2.

[0117] (Measurement of water vapor transmission rate) For the laminates manufactured in the above examples and comparative examples, a water vapor transmission rate measuring instrument (model name: PERMATRAN 3 / 33) manufactured by MOCON Corporation was used, with the sensor side facing the substrate layer surface of the barrier film. The measurement conditions were 40°C and a 100% RH atmosphere, and the water vapor transmission rate (g / m³) was measured in accordance with the JIS K7129 method. 2 The measurement was taken (day). The measurement results are shown in Table 2.

[0118] (Evaluation of residual aromatic amines (PAA)) Pouches (200 cm²) were prepared using the above laminate. These pouches were filled with a 3% acetic acid aqueous solution, sealed, and then sterilized at 121°C for 30 minutes. The acetic acid aqueous solution was removed, and the aromatic amines (PAAs) were quantitatively measured by liquid chromatography-mass spectrometry. The results are shown in Table 2.

[0119] [Table 2]

[0120] As shown in Table 2 above, in Examples 1-4, which are laminates with a gas barrier resin layer and bonded with a solvent-free adhesive containing less than 0.1% isocyanate monomer, high barrier performance and PAA levels below the specified amount were confirmed. On the other hand, in Comparative Examples 1-4, PAA levels exceeding the specified amount were detected. Even in Comparative Examples 2 and 4, which exhibited superior barrier performance, PAA levels exceeded the specified amount.

Claims

1. A laminate comprising a first substrate, a gas barrier resin layer, a solvent-free adhesive layer, and a second substrate, wherein the gas barrier resin layer is (A1) or (A2), and the isocyanate monomer in the solvent-free adhesive layer is less than 0.1%. (1) A water-soluble polymer having a hydroxyl group and Si(OR １ ) ４ , or R ２ Si ( OR ３ ) ３ (However OR １ and OR ３ represents a hydrolyzable group, R ２ A gas barrier resin layer (A1) containing one or more silicon compounds represented by (where represents an organic functional group), or hydrolyzed products of the said silicon compounds. (2) A gas barrier resin layer (A2) containing a heteroatom compound having dehydration condensation properties and a polymer having a carboxyl group.

2. The laminate according to claim 1, wherein the first substrate is an olefin resin substrate.

3. The laminate according to claim 2, wherein the first substrate and the second substrate are olefin resin substrates.

4. A packaging material comprising a laminate according to any one of claims 1 to 3.

Images