Packaging material, packaging bag, gas barrier laminate, and method for manufacturing gas barrier laminate

Abstract

This packaging material has a multi-layer structure including a paper base material, an adhesive layer, a vapor deposition layer, and a sealant film in this order. The mass ratio of the paper base material to the total mass of the packaging material is more than 75 mass%, the thickness of the sealant film is 2-20 μm, and the sealant film contains polyolefin resin.

Description

Packaging material, packaging bag, gas barrier laminate, and method for manufacturing gas barrier laminate

[0001] The present disclosure relates to a packaging material, a packaging bag, a gas barrier laminate, and a method for producing a gas barrier laminate.

[0002] Background 1: In recent years, growing environmental awareness stemming from the problem of marine plastic waste has led to a growing trend toward a plastic-free society. In the field of packaging, there is also a growing demand for replacing plastic packaging with paper packaging. Packaging materials with gas barrier properties are being used to prevent the permeation of water vapor and other substances that can deteriorate the quality of the contents.

[0003] Patent Document 1 discloses a packaging material in which a paper substrate, an adhesive layer containing a specific material, a metal layer in contact with the adhesive layer, and a sealant layer are laminated in this order, and the thickness of the adhesive layer is within a specific range. Patent Document 2 discloses a packaging material in which a paper substrate, an adhesive layer in contact with the paper substrate, and a sealant layer are laminated in this order, and the arithmetic mean roughness of the paper substrate and the tensile strength of the packaging material satisfy specific conditional expressions.

[0004] Patent Document 3 discloses an easy-open packaging material that includes a paper substrate, an anchor coat layer, a vapor deposition layer, and a sealant layer in this order, in which the weight of the paper substrate is 50% by mass or more of the entire packaging material, the thickness of the sealant layer is 2 to 40 μm, and the tensile breaking strength is within a specific range.

[0005] Patent Document 4 discloses a laminate comprising a paper substrate layer, a barrier adhesive layer, a vapor-deposited layer, and a polyethylene-based sealant layer in this order, in which the ratio of the weight of the paper substrate to the weight of the sealant layer comprising the vapor-deposited layer per unit area is 1 or more and 3 or less.

[0006] Second Background In many fields, such as food, beverages, pharmaceuticals, and chemicals, packaging materials are used according to the contents of each product. Packaging materials are required to have gas barrier properties that prevent the permeation of water vapor, oxygen, and other substances that can cause deterioration of the contents.

[0007] In recent years, growing environmental awareness stemming from issues such as marine plastic waste has led to a growing trend toward a plastic-free society. From the perspective of reducing the amount of plastic used, the use of paper instead of plastic materials has been considered in various fields. For example, Patent Document 4 discloses a laminate comprising a paper substrate layer, a vapor deposition layer, a sealant layer, and a barrier adhesive layer, in which the mass of the paper substrate layer and the mass of the sealant layer satisfy a specific relationship. Furthermore, Patent Document 5 discloses a packaging material in which a paper substrate, an adhesive layer, a metal layer in contact with the adhesive layer, and a sealant layer are laminated in this order, the thickness and material of the adhesive layer are specified, and the tensile strengths of the paper substrate and the packaging material satisfy a specific relationship.

[0008] Japanese Patent Publication No. 2020-116880 Japanese Patent Publication No. 2020-49913 Japanese Patent No. 7226679 International Publication No. 2021 / 220830 Japanese Patent No. 7322413

[0009] However, the inventors' investigations have revealed that the packaging materials disclosed in Patent Documents 1 and 2 have poor tearability when the packaging materials do not have a notch. Furthermore, the inventors' investigations have revealed that the packaging materials disclosed in Patent Documents 1 and 2 have poor tearability when the tearing direction is not along the orientation direction of the fibers of the paper substrate, even though the fibers of the paper substrate have orientation.

[0010] The easy-open packaging material of Patent Document 3 is prone to damage to the vapor deposition layer due to bending deformation of the paper, and has poor gas barrier properties at the folded portion.

[0011] Furthermore, in recent years, there has been a demand for environmentally friendly packaging materials with a high paper content. The packaging materials of Patent Documents 1, 2 and 4 have room for improvement in terms of the paper content.

[0012] The present disclosure provides a packaging material and a packaging bag that are excellent in tearability regardless of the tearing direction even when not having a notch, have excellent water vapor barrier properties even after folding, and are environmentally friendly.

[0013] Second Problem However, the inventors' investigations revealed that the laminate disclosed in Patent Document 4 may experience problems during transportation for bag making, and that there is room for improvement in terms of suitability for bag making.

[0014] Furthermore, from the viewpoint of the Law for Promoting Effective Utilization of Resources, it is required to increase the ratio of paper in the entire gas barrier laminate. The laminate disclosed in Patent Document 1 has room for improvement in terms of environmental compatibility.

[0015] Furthermore, the inventors' investigations have revealed that the packaging material disclosed in Patent Document 5 suffers from paper breakage during processing and bag production, and that there is room for improvement in terms of bag production suitability. Furthermore, Patent Document 5 does not disclose increasing the paper ratio of the entire packaging material.

[0016] The present disclosure has been made in view of the above circumstances and provides a gas barrier laminate that is environmentally friendly and has sufficient bag-forming suitability. The present disclosure also provides a packaging bag including such a gas barrier laminate, and a method for producing such a gas barrier laminate.

[0017] First Invention Group In order to solve the above-mentioned problems, the present disclosure provides the following packaging materials and packaging bags. [1] A packaging material having a laminated structure including a paper substrate, an adhesive layer, a vapor deposition layer, and a sealant film, in this order, wherein the mass ratio of the paper substrate to the total mass of the packaging material is more than 75 mass%, the thickness of the sealant film is 2 to 20 μm, and the sealant film contains a polyolefin resin. [2] The packaging material according to [1], wherein the composite modulus measured on one main surface of the sealant film is 1.25 to 4.00 GPa. [3] The packaging material according to [1] or [2], wherein the polyolefin resin contains a polypropylene resin. [4] The packaging material according to any of [1] to [3], wherein the thickness of the sealant film is 4 to 15 μm. [5] The packaging material according to any of [1] to [4], further including a barrier coat layer between the vapor deposition layer and the sealant film. [6] The packaging material according to any one of [1] to [5], further comprising a barrier coating layer between the paper substrate and the vapor deposition layer. [7] The packaging material according to [5] or [6], wherein the barrier coating layer comprises a polyvinyl alcohol-based resin. [8] The packaging material according to any one of [1] to [7], wherein the thickness of the adhesive layer is 2 to 5 μm. [9] The packaging material according to any one of [1] to [8], wherein the adhesive layer comprises a urethane-based adhesive comprising a polyol having two or more hydroxyl groups in one molecule and an isocyanate compound having two or more isocyanate groups in one molecule.

[10] The packaging material according to any one of [1] to [9], wherein the sealant film is a stretched film.

[11] Let X be the basis weight of the paper substrate, and X be the thickness of 1 m of the sealant film. ２

[14] A method for producing the packaging material according to any one of [1] to

[11] , wherein the ratio of X to Y (X / Y) is 3.7 or more and 30.0 or less, where Y is the weight per unit area.

[12] A packaging bag including the packaging material according to any one of [1] to

[11] .

[13] The packaging bag according to

[12] , which has a folding section.

[14] A method for producing the packaging material according to any one of [1] to

[11] , comprising the following steps 1 to 3: Step 1: forming a vapor deposition layer on a main surface of a sealant film to obtain a first laminate; Step 2: applying an adhesive to a main surface of a paper base material, drying the resulting coating film to form a dried product, thereby obtaining a second laminate; and Step 3: laminating the first laminate and the second laminate together so that the vapor deposition layer and the dried product face each other.

[0018] Second Invention Group One aspect of the present disclosure relates to the following gas barrier laminate, a method for producing a gas barrier laminate, and a packaging bag: [1] A gas barrier laminate having a laminate structure including, in this order, a paper substrate, a water-soluble polymer layer having oxygen barrier properties, a vapor deposition layer, and a sealant film, wherein the sealant film contains a polyolefin resin, and the basis weight of the paper substrate is X, and the thickness of 1 m of the sealant film is X. ２ When the weight per unit area is Y, the ratio of X to Y (X / Y) is 3.7 or more and 30.0 or less, and X is 10 g / m ２ More than 100g / m ２ [2] The gas barrier laminate according to [1], wherein the polyolefin resin comprises a polypropylene resin. [3] The gas barrier laminate according to [1] or [2], wherein the thickness of the sealant film is 4 μm or more and 15 μm or less. [4] The gas barrier laminate according to any one of [1] to [3], wherein the ratio (X / Y) is 7.0 or more and 30.0 or less. [5] The gas barrier laminate according to any one of [1] to [3], wherein the ratio (X / Y) is 16.5 or more and 30.0 or less. [6] The gas barrier laminate according to any one of [1] to [3], wherein the basis weight of the paper substrate is 40 g / m ２ 80g / m or more ２The gas barrier laminate according to any one of [1] to [5], which is as follows: [7] A packaging bag comprising the gas barrier laminate according to any one of [1] to [6]. [8] A method for producing the gas barrier laminate according to any one of [1] to [6], comprising the following steps (A) to (C): Step (A): preparing a first laminate comprising a sealant film and a vapor deposition layer; Step (B): applying a composition containing a water-soluble polymer and water to the surface of the first laminate on the vapor deposition layer side or to the surface of the paper substrate; and Step (C): laminating the first laminate and the paper substrate together via the composition so that the vapor deposition layer and the paper substrate face each other, and drying the composition to form a water-soluble polymer layer, thereby obtaining a gas barrier laminate.

[0019] According to the first invention group, which is one aspect of the present disclosure, there are provided packaging materials and packaging bags that have excellent tearability regardless of the tearing direction even when they do not have a notch, have excellent water vapor barrier properties even after folding, and are environmentally friendly.

[0020] According to a second invention group which is one aspect of the present disclosure, a gas barrier laminate having excellent environmental compatibility and sufficient bag-forming suitability is provided. The present disclosure also provides a packaging bag including such a gas barrier laminate and a method for producing such a gas barrier laminate.

[0021] Fig. 1 is a schematic cross-sectional view showing an easy-open packaging material according to one embodiment of the first invention group of the present disclosure. Fig. 2 is a schematic cross-sectional view showing an easy-open packaging material according to another embodiment of the first invention group of the present disclosure. Fig. 3 is a perspective view showing a packaging bag according to one embodiment of the first invention group and one embodiment of the second invention group of the present disclosure. Fig. 4 is a schematic cross-sectional view showing a gas barrier laminate according to one embodiment of the second invention group of the present disclosure. Fig. 5 is a perspective view showing a packaging bag according to one embodiment of the second invention group of the present disclosure.

[0022] First Invention Group Preferred embodiments of the present disclosure will now be described in detail, although the present disclosure is not limited to the following embodiments.

[0023] <Easy-open packaging material> {First embodiment} The easy-open packaging material according to the first embodiment will be described below. FIG. 1 is a schematic cross-sectional view showing the easy-open packaging material according to the first embodiment. A packaging material 10 according to one embodiment has a laminated structure including, in this order, a paper substrate 1, an adhesive layer 2, a barrier coat layer 3, a vapor deposition layer 4, and a sealant film 5. The mass ratio of the paper substrate to the total mass of the packaging material is greater than 75 mass%. The sealant film has a thickness of 2 to 20 μm, contains a polyolefin resin, and has a composite modulus of elasticity measured on one main surface of the sealant film of 1.25 to 4.00 GPa.

[0024] The packaging material 10 is environmentally friendly and has excellent tearability regardless of the tear direction even when notched, and excellent water vapor barrier properties even after folding. The packaging material 10 also has excellent bag-forming suitability. The inventors speculate that the reason for these effects is as follows: When the sealant film has a composite elastic modulus of 1.25 GPa or more, deformation of the sealant film during tearing is suppressed, thereby improving tearability. Furthermore, when the composite elastic modulus is 4.00 GPa or less, heat sealing properties are improved, thereby improving bag-forming suitability. Furthermore, the packaging material 10 has an adhesive layer 2 between the paper substrate 1 and the barrier coat layer 3, and the sealant film has a thickness of 2 to 20 μm. As a result, the packaging material 10 has excellent bag-forming suitability, tearability, and water vapor barrier properties after folding, even though the paper substrate has a mass ratio of more than 75 mass%.

[0025] In this specification, "easy-open property" and "tearability" refer to the property that the packaging bag can be opened by tearing it by hand without using scissors or a knife.

[0026] Each layer of the packaging material 10 will now be described in detail.

[0027] [Paper substrate] The paper substrate 1 is not particularly limited and may be appropriately selected depending on the application of the packaging bag to which the packaging material 10 is applied. There are no particular limitations on the paper substrate 1 as long as it is paper whose main component is plant-derived pulp. Specific examples of the paper substrate 1 include fine paper, special fine paper, coated paper, art paper, cast-coated paper, imitation paper, kraft paper, and glassine paper. The thickness of the paper substrate 1 may be, for example, 30 μm or more and 100 μm or less, or 30 μm or more and 70 μm or less.

[0028] The basis weight (X) of the paper base material is preferably 30 g / m because it tends to be more environmentally friendly and improves the bag-making speed and lamination speed. ２ It is preferable that the weight is 40 g / m or more. ２ The basis weight (X) of the paper substrate is preferably 80 g / m or more, since this tends to improve the heat sealability during bag production and increase the bag production speed. ２ Preferably, it is 70 g / m or less. ２ More preferably, it is:

[0029] The paper substrate 1 may have a coating layer at least on the side that contacts the adhesive layer 2. The coating layer can prevent the adhesive layer 2 from penetrating into the paper and also serve to fill in irregularities in the paper. The coating layer may contain, for example, various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate copolymers, polyvinyl alcohol resins, cellulose resins, paraffin (wax), etc. as binder resins, and may also contain clay, kaolin, calcium carbonate, talc, mica, etc. as fillers.

[0030] The thickness of the coating layer may be, for example, 1 to 10 μm, or 3 to 8 μm.

[0031] The mass ratio of the paper base material 1 to the total mass of the packaging material 10 is preferably 80 mass% or more, more preferably 85 mass% or more, and even more preferably 90 mass% or more, based on the entire packaging material. When the mass ratio of the paper base material is in this range, the amount of plastic material used can be sufficiently reduced, the entire packaging material can be said to be made of paper, and the packaging material has excellent recyclability.

[0032] [Adhesive Layer] The adhesive layer 2 adheres the paper base material 1 to the barrier coat layer 3. Various adhesive layers can be used as the adhesive layer 2 as long as they adhere the paper base material 1 to the barrier coat layer 3, and examples thereof include a cured product of a urethane adhesive, a cured product of an epoxy adhesive, and a water-soluble adhesive.

[0033] <Urethane-based adhesive> A urethane-based adhesive is a resin composition containing a polyol having two or more hydroxyl groups per molecule and an isocyanate compound having two or more isocyanate groups per molecule. Urethane bonds are generated by curing the urethane-based adhesive. The urethane-based adhesive is preferably a two-component curing type. Among urethane-based adhesives, aliphatic ester urethane-based adhesives are preferred because they have excellent heat resistance and excellent gas barrier properties at high temperatures. Among urethane-based adhesives, aromatic ether urethane-based adhesives and aromatic ester urethane-based adhesives are preferred because they have excellent gas barrier properties.

[0034] The urethane adhesive may have gas barrier properties. Methods for imparting gas barrier properties to a urethane adhesive include, for example, a method using a polyol having a skeleton with gas barrier properties, a method including a phosphoric acid-modified compound in the resin composition, and a method including a plate-like inorganic compound in the resin composition. These methods can be used alone or in combination of two or more.

[0035] The polyol having a skeleton with barrier properties preferably has a main skeleton of polyester or polyester polyurethane, the polyester containing a structure derived from an ortho-oriented aromatic dicarboxylic acid or an anhydride thereof. The polyester portion of the main skeleton may be obtained by polycondensation reaction of a polycarboxylic acid and a polyhydric alcohol.

[0036] Examples of polycarboxylic acids include aliphatic polycarboxylic acids and aromatic polycarboxylic acids, such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid.

[0037] Examples of aromatic polycarboxylic acids include orthophthalic acid, terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,2-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid and anhydrides of these dicarboxylic acids, as well as polybasic acids such as p-hydroxybenzoic acid and p-(2-hydroxyethoxy)benzoic acid. The polycarboxylic acids can be used alone or in combination of two or more.

[0038] The polycarboxylic acid is preferably an ortho-oriented aromatic dicarboxylic acid or an anhydride thereof. The content of the ortho-oriented aromatic dicarboxylic acid or an anhydride thereof is preferably 70 to 100 mass% based on the total amount of the polycarboxylic acid components constituting the polyester.

[0039] Examples of the ortho-oriented aromatic dicarboxylic acid include orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, and anhydrides of these dicarboxylic acids.

[0040] The polyhydric alcohols include aliphatic polyhydric alcohols and aromatic polyhydric phenols, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol.

[0041] Examples of aromatic polyhydric phenols include hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, bisphenol F, and tetramethylbiphenol, as well as ethylene oxide-extended products and hydrogenated alicyclic phenols thereof.

[0042] The isocyanate compound may be an aromatic compound having an aromatic ring, an aliphatic compound having no aromatic ring, a low molecular weight compound or a high molecular weight compound, a diisocyanate compound having two isocyanate groups or a polyisocyanate compound having three or more isocyanate groups, or a blocked isocyanate compound obtained by addition reaction with an isocyanate blocking agent.

[0043] The isocyanate compound is preferably a polyisocyanate compound from the viewpoint of the adhesiveness of the adhesive layer 2. The isocyanate compound is preferably one having an aromatic ring, since it imparts oxygen barrier properties to the adhesive layer 2, and is particularly preferably an isocyanate compound containing a metaxylene skeleton.

[0044] Examples of the isocyanate compound include tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, metaxylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and trimers of these isocyanate compounds. These isocyanate compounds may be adducts, biurets, or allophanates obtained by reacting an isocyanate compound with a low molecular weight active hydrogen compound such as ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, or metaxylylenediamine, or an alkylene oxide adduct thereof, or a high molecular weight active hydrogen compound such as various polyester resins, polyether polyols, or polyamides.

[0045] <Epoxy-Based Adhesive> The epoxy-based adhesive is a resin composition containing an epoxy resin and an epoxy resin curing agent.

[0046] The epoxy resin may have a saturated bond or an unsaturated bond and may be any of an aliphatic compound, an alicyclic compound, an aromatic compound, and a heterocyclic compound. In order to exhibit higher gas barrier properties, the epoxy resin is preferably an epoxy resin containing an aromatic ring or an alicyclic structure in the molecule.

[0047] Examples of epoxy resins include epoxy resins having a glycidylamino group derived from meta-xylylenediamine, epoxy resins having a glycidylamino group derived from 1,3-bis(aminomethyl)cyclohexane, epoxy resins having a glycidylamino group derived from diaminodiphenylmethane, epoxy resins having a glycidylamino group and / or a glycidyloxy group derived from para-aminophenol, epoxy resins having a glycidyloxy group derived from bisphenol A, epoxy resins having a glycidyloxy group derived from bisphenol F, epoxy resins having a glycidyloxy group derived from phenol novolac, and epoxy resins having a glycidyloxy group derived from resorcinol. One type of epoxy resin may be used alone, or two or more types may be used in combination. From the viewpoint of gas barrier properties, epoxy resins having a glycidylamino group derived from meta-xylylenediamine and epoxy resins having a glycidyloxy group derived from bisphenol F are preferred, with epoxy resins having a glycidylamino group derived from meta-xylylenediamine being more preferred.

[0048] The epoxy resin curing agent may be a reaction product of metaxylylenediamine or paraxylylenediamine with an unsaturated carboxylic acid and / or its derivative represented by the following formula (1):

[0049] [In formula (1), R １ represents an alkyl group having 1 to 8 carbon atoms, an aralkyl group having 1 to 8 carbon atoms, or an aryl group.]

[0050] The use of metaxylylenediamine or paraxylylenediamine as a precursor of an epoxy resin curing agent further improves gas barrier properties. From the viewpoint of gas barrier properties, metaxylylenediamine is preferred. Metaxylylenediamine or paraxylylenediamine may be used alone or in combination of two or more.

[0051] By using the unsaturated carboxylic acid represented by the above formula (1) and / or its derivative as a precursor of the epoxy resin curing agent, good adhesive properties are exhibited. Examples of the unsaturated carboxylic acid represented by the above formula (1) and / or its derivative include unsaturated carboxylic acids such as crotonic acid, 2-pentenoic acid, 2-hexenoic acid, 4-methyl-2-pentenoic acid, 2-heptenoic acid, 4-methyl-2-hexenoic acid, 5-methyl-2-hexenoic acid, 4,4-dimethyl-2-pentenoic acid, 4-phenyl-2-butenoic acid, cinnamic acid, o-methylcinnamic acid, m-methylcinnamic acid, p-methylcinnamic acid, 2-octenoic acid, 2-nonenoic acid, 2-decenoic acid, and 2-undecenoic acid, as well as derivatives thereof (e.g., esters, amides, acid anhydrides, acid chlorides, etc.), but are not particularly limited thereto. The unsaturated carboxylic acid represented by the above formula (1) and / or its derivative may be used alone or in combination of two or more.

[0052] The unsaturated carboxylic acid and / or its derivative represented by the above formula (1) further improves the gas barrier property and adhesive property by reducing the R １ is preferably at least one selected from the group consisting of unsaturated carboxylic acids and derivatives thereof, wherein R is a hydrocarbon group having 1 to 3 carbon atoms or a phenyl group, more preferably at least one selected from the group consisting of crotonic acid and crotonic acid derivatives, and even more preferably at least one selected from the group consisting of crotonic acid and crotonic acid esters. As the crotonic acid ester, alkyl esters having 1 to 3 carbon atoms are more preferred, and methyl crotonate is even more preferred.

[0053] <Water-Soluble Adhesive> As the material for the water-soluble adhesive, polysaccharides such as tapioca and starch, polyvinyl alcohol, and various other water-soluble adhesives can be used.

[0054] The adhesive layer 2 may be formed using a one-component curing or two-component curing adhesive (dry lamination method), may be formed using a solvent-free adhesive (non-solvent dry lamination method), or may be formed by extruding a molten resin onto the surface of the paper substrate 1 or the barrier coating layer 3 (extrusion lamination method).

[0055] The thickness of the adhesive layer 2 is preferably 0.01 μm or more, and more preferably 2 μm or more or 3 μm or more, from the viewpoint of improving the adhesiveness of the adhesive layer 2, and is preferably 10 μm or less, and more preferably 5 μm or less, since the amount of plastic material used is further reduced. The thickness of the adhesive layer 2 may be 0.01 μm or more and 10 μm or less, 0.01 μm or more and 5 μm or less, 2 μm or more and 10 μm or less, 2 μm or more and 5 μm or less, 3 μm or more and 10 μm or less, or 3 μm or more and 5 μm or less.

[0056] [Barrier Coat Layer] The barrier coat layer 3 is provided on the surface of the vapor-deposited layer 4 to improve adhesion between the paper substrate 1 and the vapor-deposited layer 4 and to improve the gas barrier properties of the packaging material. The barrier coat layer 3 is not particularly limited, but preferably contains a polyvinyl alcohol-based resin and a polyolefin having a polar group, as this provides even better gas barrier properties (particularly water vapor barrier properties), and more preferably contains a polyvinyl alcohol-based resin, as this provides even better water vapor barrier properties and oxygen barrier properties.

[0057] The barrier coat layer 3 contains a polyolefin having a polar group, which allows the formation of a dense film due to the crystallinity of the polyolefin, thereby exhibiting water vapor barrier properties. The crystallinity of the polyolefin provides water vapor barrier properties, and the presence of a polar group provides adhesion to the vapor deposition layer 4.

[0058] The polyolefin having a polar group may have at least one selected from a carboxyl group, a salt of a carboxyl group, a carboxylic anhydride group, and a carboxylic acid ester.

[0059] As the polyolefin having a polar group, a copolymer of ethylene or propylene with an unsaturated carboxylic acid (an unsaturated compound having a carboxyl group such as acrylic acid, methacrylic acid, or maleic anhydride) or an unsaturated carboxylic acid ester, or a salt of a carboxylic acid neutralized with a basic compound may be used, or a copolymer of ethylene or propylene with vinyl acetate, an epoxy compound, a chlorine compound, a urethane compound, a polyamide compound, or the like may also be used.

[0060] Specific examples of polyolefins having a polar group include copolymers of acrylic ester and maleic anhydride, ethylene-vinyl acetate copolymers, and ethylene-glycidyl methacrylate copolymers.

[0061] Examples of polyvinyl alcohol resins include fully saponified polyvinyl alcohol resins, partially saponified polyvinyl alcohol resins, modified polyvinyl alcohol resins, ethylene-vinyl alcohol copolymer resins, etc. The degree of polymerization of the polyvinyl alcohol resin is preferably 300 or more and 1700 or less. If the degree of polymerization is 300 or more, the gas barrier properties and flex resistance of the packaging material will be good, and if the degree of polymerization is 1700 or less, the viscosity of the coating liquid of the polyvinyl alcohol resin described below will be low, resulting in good coatability.

[0062] When the barrier coating layer 3 contains a polyvinyl alcohol-based resin, it has excellent flexibility, and can suppress cracking of the vapor deposition layer described below after bending (folding), thereby suppressing deterioration of the gas barrier properties, and can improve adhesion between the vapor deposition layer and the barrier coating layer 3.

[0063] The barrier coat layer 3 may contain other components in addition to the polyolefin and polyvinyl alcohol resins described above, such as resins of polyolefins other than the above-mentioned polyolefins, polyacrylics, polyesters, polyurethanes, polyethyleneimines, polylactic acids, polyamides, starch and its derivatives, and cellulose derivatives, as well as additives such as silane coupling agents, organic titanates, glycerin, glycols, casein, and waxes.

[0064] The total content of the polyolefin and polyvinyl alcohol resin in the barrier coat layer 3 may be, for example, 50% by mass or more, 70% by mass or more, 90% by mass or more, or 100% by mass.

[0065] The thickness of the barrier coat layer 3 may be, for example, 0.1 μm or more, 1 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the barrier coat layer 3 is 0.1 μm or more, more stable barrier properties can be ensured. Furthermore, if the thickness of the barrier coat layer 3 is 20 μm or less, the packaging material 10 will be more environmentally friendly.

[0066] Examples of solvents contained in the coating liquid for the barrier coat layer 3 include water, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, n-pentyl alcohol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used alone or in combination. Among these, from the viewpoint of properties, methyl alcohol, ethyl alcohol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of the environment, methyl alcohol, ethyl alcohol, isopropyl alcohol, and water are preferred.

[0067] The method for providing the barrier coat layer 3 is not particularly limited. When the barrier coat layer 3 contains at least one of the above-mentioned polyolefin and polyvinyl alcohol-based resin, it can be obtained by applying a coating liquid containing at least one of the above-mentioned polyolefin and polyvinyl alcohol-based resin and a solvent onto the vapor-deposited layer and drying it. Furthermore, polyolefin wax may be added to prevent blocking. The polyolefin wax in the coating liquid preferably has a large particle size so as to reduce the contact area. Although not particularly limited, the particle size may specifically be 0.1 μm or more, 1 μm or more, 10 μm or less, 7 μm or less, or 5 μm or less.

[0068] [Vapor-Deposited Layer] The vapor-deposited layer 4 is a layer formed by vapor-depositing a metal or an inorganic compound. The vapor-deposited layer 4 is provided on the surface of the sealant film 5 so as to be in contact with the sealant film 5.

[0069] The vapor-deposited layer 4 may be obtained by vapor-depositing aluminum, or may be aluminum oxide (AlO ｘ ), silicon oxide (SiO ｘ ) etc.

[0070] The thickness of the vapor-deposited layer 4 is preferably 20 to 200 nm. When the thickness of the vapor-deposited layer is 20 nm or more, defects are less likely to occur in the vapor-deposited film, and the gas barrier properties, particularly those at bent portions, tend to be excellent. When the thickness of the vapor-deposited layer is 200 nm or less, wrinkles and defects due to the heat load during the vapor deposition process are less likely to occur in the sealant film, and deterioration of the gas barrier properties tends to be less likely to occur. The thickness of the vapor-deposited layer 4 is more preferably 30 to 180 nm, and even more preferably 50 to 150 nm.

[0071] The deposition layer 4 is preferably formed by a vacuum deposition method from the viewpoint of oxygen gas barrier performance and film uniformity. While known deposition methods include vacuum deposition, sputtering, and chemical vapor deposition (CVD), vacuum deposition is preferred due to its high deposition rate and high productivity. Among vacuum deposition methods, electron beam heating is particularly effective because it allows for easy control of the deposition rate via the irradiation area and electron beam current, and allows for rapid heating and cooling of the deposition material.

[0072] [Sealant Film] The sealant film 5 contains a polyolefin resin. Examples of polyolefin resins that can be used include ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), high-density polyethylene resin (HDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer; and mixtures thereof. Polypropylene resin is preferred as the polyolefin resin. Due to its high rigidity, the packaging material 10 tends to have even better bag-making suitability.

[0073] The content of the polyolefin resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film. The content of the polyethylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film. The content of the polypropylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film.

[0074] Examples of resins other than polyolefin resins include polyester resins, polylactic acid, and polybutylene succinate.

[0075] The composite elastic modulus measured on one main surface of the sealant film is 1.25 GPa or more, preferably 1.30 GPa or more, and more preferably 1.35 GPa or more. This tends to provide the packaging material 10 with better tear resistance. The composite elastic modulus is 4.00 GPa or less, preferably 3.50 GPa or less, more preferably 3.00 GPa or less, even more preferably 2.50 GPa or less, even more preferably 2.00 GPa or less, and particularly preferably 1.50 GPa or less. This tends to provide the packaging material 10 with better bag-making suitability.

[0076] That is, the composite elastic modulus is 1.25 GPa or more and 4.00 GPa or less, 1.25 GPa or more and 3.50 GPa or less, 1.25 GPa or more and 3.00 GPa or less, 1.25 GPa or more and 2.50 GPa or less, 1.25 GPa or more and 2.00 GPa or less, 1.25 GPa or more and 1.50 GPa or less, 1.30 GPa or more and 4.00 GPa or less, 1.30 GPa or more and 3.50 GPa or less, 1.30 GPa or more and 3.00 GPa or less or lower, 1.30 GPa or more and 2.50 GPa or less, 1.30 GPa or more and 2.00 GPa or less, 1.30 GPa or more and 1.50 GPa or less, 1.35 GPa or more and 4.00 GPa or less, 1.35 GPa or more and 3.50 GPa or less, 1.35 GPa or more and 3.00 GPa or less, 1.35 GPa or more and 2.50 GPa or less, 1.35 GPa or more and 2.00 GPa or less, or 1.35 GPa or more and 1.50 GPa or less.

[0077] The composite elastic modulus measured on one main surface of the sealant film is measured by nanoindentation, which is a measurement method in which a quasi-static indentation test is performed on a target object to obtain the mechanical properties of the sample.

[0078] The composite elastic modulus measured on one main surface of the sealant film can be adjusted by changing the material of the sealant film, the stretching ratio of the sealant film or the temperature conditions during stretching, or the density or crystallinity of the resin. The composite elastic modulus tends to increase as the density and crystallinity increase.

[0079] The sealant film has a pair of opposing main surfaces, which are surfaces that are larger in area than the other surfaces of the polyhedron (the sealant film, which is a thin, three-dimensional body).

[0080] 1m of sealant film ２ The weight per unit area (Y) is 3.0 g / m ２ or more, and ２ It may be the following:

[0081] The basis weight of the paper substrate 1 is X, and 1 m of the sealant film 5 ２When the weight per unit area is Y, the ratio of X to Y (X / Y) is preferably 3.7 or more, more preferably 7.0 or more, and even more preferably 16.5 or more. When the ratio (X / Y) is 3.7 or more, breakage of the packaging material 10 during transportation is suppressed. The ratio (X / Y) is preferably 30.0 or less. This makes the packaging material 10 easier to transport. The ratio (X / Y) may be 3.7 or more and 30.0 or less, 7.0 or more and 30.0 or less, or 16.5 or more and 30.0 or less.

[0082] The sealant film may be unstretched, uniaxially stretched, or biaxially stretched. Since the sealant film tends to have a composite elastic modulus in the range of 1.25 to 4.00 GPa, it is preferably a stretched film, and more preferably a stretched polyethylene film.

[0083] The thickness of the sealant film is 2 μm or more, and from the viewpoint of durability against heat when forming the vapor-deposited layer, it is preferably 4 μm or more, more preferably 6 μm or more, and even more preferably 8 μm or more. The thickness of the sealant film is 20 μm or less, and since there is a tendency for the film to have better tearability, it is preferably 18 μm or less, more preferably 15 μm or less, and even more preferably 12 μm or less.

[0084] The thickness of the sealant film may be 2 μm or more and 20 μm or less, 2 μm or more and 18 μm or less, 2 μm or more and 15 μm or less, 2 μm or more and 12 μm or less, 4 μm or more and 20 μm or less, 4 μm or more and 18 μm or less, 4 μm or more and 15 μm or less, 4 μm or more and 12 μm or less, 6 μm or more and 20 μm or less, 6 μm or more and 18 μm or less, 6 μm or more and 15 μm or less, 6 μm or more and 12 μm or less, 8 μm or more and 20 μm or less, 8 μm or more and 18 μm or less, 8 μm or more and 15 μm or less, or 8 μm or more and 12 μm or less.

[0085] {Second Embodiment} An easy-open packaging material according to a second embodiment will be described below. Points not described below are the same as those according to the first embodiment unless inconsistencies arise. FIG. 2 is a schematic cross-sectional view showing a packaging material according to the second embodiment. A packaging material 15 according to one embodiment differs from the packaging material 10 in that the sealant film 5 has a multilayer structure including two layers, a skin layer 5a and a core layer 5b. In the packaging material 15, the composite elastic modulus measured on the main surface on the skin layer 5a side is 1.25 to 4.00 GPa.

[0086] [Sealant Film] The sealant film has a multilayer structure including two layers: a core layer and a skin layer. The skin layer is one of the outermost layers of the sealant film. A sealant film having a multilayer structure can be obtained, for example, by co-extrusion of different resins.

[0087] (Skin Layer) The skin layer contains a polyolefin resin, such as a polypropylene resin or a polyethylene resin.

[0088] The content of the polyolefin resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the skin layer. The content of the polyethylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the skin layer. The content of the polypropylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the skin layer.

[0089] The polypropylene resin may be a copolymer of propylene and another monomer. The other monomer used in the copolymer may be, for example, an α-olefin such as ethylene, 1-butene, or 1-hexene. The copolymer may be a random copolymer.

[0090] The content of propylene units in the copolymer of propylene and other monomers may be 80 mol% or more, 90 mol% or more, 95 mol% or more, or 96 mol% or more, based on the total amount of monomer units, and may be 99.7 mol% or less, 99.5 mol% or less, 99 mol% or less, or 98 mol% or less.

[0091] The skin layer may contain, as needed, organic additives such as antioxidants, stabilizers, lubricants, and antistatic agents, and may also contain inorganic additives such as silica, zeolite, hydrotalcite, silicon particles, and siloid.

[0092] The thickness of the skin layer is not particularly limited, but may be, for example, 0.1 μm to 5 μm, 0.2 μm to 3 μm, or 0.3 μm to 2 μm.

[0093] (Core Layer) The core layer 5b contains a polyolefin resin, such as a polypropylene resin or a polyethylene resin.

[0094] The content of the polyolefin resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the core layer. The content of the polyethylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the core layer. The content of the polypropylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the core layer.

[0095] Examples of polypropylene resins include homopolypropylene resins, which are homopolymers of propylene, random copolymers of propylene and α-olefins, and mixtures thereof. From the viewpoint of improving heat resistance, homopolypropylene resins, which are homopolymers of propylene, are preferred.

[0096] The core layer may contain, as needed, organic additives such as antioxidants, stabilizers, lubricants, and antistatic agents, and may also contain inorganic additives such as silica, zeolite, hydrotalcite, silicon particles, and siloid.

[0097] The thickness of the core layer is not particularly limited, but may be, for example, 0.5 μm to 15 μm, 1 μm to 12 μm, or 2 μm to 10 μm.

[0098] Although the first and second embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above embodiments. For example, packaging materials according to other embodiments may not include a barrier coating layer. Furthermore, in packaging materials according to other embodiments, the barrier coating layer may be located between the vapor deposition layer and the sealant film, rather than between the adhesive layer and the vapor deposition layer. Furthermore, packaging materials according to other embodiments may include a barrier coating layer located between the vapor deposition layer and the sealant film, in addition to the barrier coating layer located between the adhesive layer and the vapor deposition layer. Furthermore, although the sealant film in the second embodiment has two layers, it may have three layers, or four or more layers.

[0099] <Manufacturing Method of Packaging Material> A manufacturing method of a packaging material according to one embodiment will be described below. This manufacturing method is a method for manufacturing packaging materials according to the first and second embodiments. The manufacturing method of a packaging material according to this embodiment includes the following steps 1 to 3. Regarding steps 1 and 2, step 1 may be performed first, step 2 may be performed first, or both may be performed simultaneously. Step 1: A step of forming a vapor deposition layer on the main surface of a sealant film to obtain a first laminate. Step 2: A step of applying an adhesive to the main surface of a paper substrate, drying the resulting coating film to form a dried product, thereby obtaining a second laminate. Step 3: A step of bonding the first laminate and the second laminate together so that the vapor deposition layer and the dried product face each other.

[0100] Alternatively, instead of steps 2 and 3, the following steps 2A and 3A may be performed: Step 2A: A step of applying an adhesive to the main surface of the sealant film on which the vapor-deposited layer has been formed, drying the resulting coating film to form a dried product, thereby obtaining a third laminate; and Step 3A: A step of laminating the third laminate and the paper substrate together so that the dried product faces the paper substrate.

[0101] Paper substrates have higher heat resistance than resin sealant films. Therefore, as described below, when drying the coating film in steps 2 and 2A, it is dried at a higher temperature. Therefore, performing step 2, in which a dried product is formed on a paper substrate, is advantageous in that the drying time is likely to be shorter. On the other hand, adhesives are less likely to penetrate into resin sealant films than into paper substrates. Therefore, step 2A, in which adhesive is applied to a sealant film, is more likely to produce a uniform and thicker dried product (adhesive layer). As a result, performing step 2A is advantageous in that it is more likely to increase the adhesion strength between the paper substrate and the sealant film.

[0102] In step 1, a known method can be used to form the vapor deposition layer, such as a physical vapor deposition method (PVD method) including vacuum deposition, sputtering, and ion plating, and a chemical vapor deposition method (CVD method) including plasma-enhanced chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition.

[0103] In steps 2 and 2A, the drying method may be hot air drying, heat roll drying, high frequency irradiation, infrared irradiation, UV irradiation, etc. The drying temperature is not particularly limited, but is preferably from 60° C. to 140° C., more preferably from 90° C. to 130° C., and even more preferably from 100° C. to 120° C. The drying time is preferably from 10 seconds to 3 minutes, and more preferably from 30 seconds to 90 seconds.

[0104] In step 3, the first laminate and the second laminate may be bonded together while being pressed by a roller. The pressure applied by the roller may be 0.05 MPa or more and 0.5 MPa or less. Heating may be performed simultaneously with pressing. If heating is performed, the temperature may be room temperature or more and 80°C or less.

[0105] In step 3A, the third laminate and the paper substrate may be bonded together while being pressed by a roller. The pressure applied by the roller may be the same as in step 3. Heating may also be performed simultaneously with pressing. If heating is performed, the temperature may be the same as in step 3.

[0106] The packaging material manufacturing method according to this embodiment forms a vapor-deposited layer on the main surface of a sealant film. Compared to forming a vapor-deposited layer on a paper substrate, a film is less likely to break than paper, so the minimum film thickness that can be stably transported through a vapor deposition machine is thinner. Thinner thickness allows for a longer winding length at the maximum winding diameter that can be inserted into the vapor deposition machine, resulting in a larger batch throughput. Furthermore, paper contains several percent moisture and has a higher amount of volatile components under reduced pressure than a sealant film. This can result in longer evacuation times during vapor deposition, or the volatile components can adversely affect the formation of the vapor-deposited film. The packaging material manufacturing method according to this embodiment forms a vapor-deposited layer on the main surface of the sealant film, improving the productivity of vapor-deposited film formation and the quality of the vapor-deposited film.

[0107] The method for producing a packaging material according to this embodiment may further include the following step 4: forming a barrier coat layer on the main surface of the sealant film.

[0108] Step 4 may be performed before step 1. In this case, the vapor deposition layer is formed on the surface of the barrier coat layer. Step 4 may be performed after step 1. In this case, the barrier coat layer is formed on the surface of the vapor deposition layer.

[0109] <Packaging Bag> Figure 3 is a perspective view showing a gusseted bag 20 made from packaging material 10. A packaging bag is produced by sealing the opening at the top of the gusseted bag 20. The gusseted bag 20 has portions where the packaging material 10 is folded (folded portions B1, B2). Folded portion B1 is a portion where the packaging material 10 is folded in a valley direction when viewed from the innermost layer side, while folded portion B2 is a portion where the packaging material 10 is folded in a mountain direction when viewed from the innermost layer side.

[0110] The packaging bag may be formed into a bag shape by folding one sheet of packaging material in half so that the sealant films 5 face each other, then folding it appropriately into the desired shape and heat sealing it, or may be formed into a bag shape by stacking two sheets of packaging material together so that the sealant films 5 face each other, and then heat sealing it.

[0111] In the packaging bag according to this embodiment, the heat seal strength is not particularly limited. The heat seal strength can be appropriately changed by changing the thickness of the sealant film 5. For example, when storing light contents, the heat seal strength may be 2 N or more and 10 N or less. Furthermore, when storing heavy contents, the heat seal strength is preferably 10 N or more.

[0112] The packaging bag can contain contents such as food, medicine, etc. It is particularly suitable for containing food such as sweets. The packaging bag according to this embodiment can maintain high gas barrier properties even when it has a shape with a folded portion.

[0113] In this embodiment, a gusset bag is given as an example of a packaging bag, but the packaging material according to the above embodiment may be used to produce, for example, a pillow bag, a three-side seal bag, or a standing pouch. The packaging bag may be made of packaging material 15. The packaging material used for gusset bag 20 may be the packaging material according to the first embodiment, or may be the packaging material according to the second embodiment.

[0114] Second Invention Group Preferred embodiments of the present disclosure will now be described in detail. However, the present disclosure is not limited to the following embodiments. In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range may be replaced with the upper or lower limit of another numerical range. Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. Furthermore, the upper and lower limits individually described can be combined in any combination.

[0115] <Gas barrier laminate> Figure 4 is a schematic cross-sectional view showing a gas barrier laminate according to one embodiment. A gas barrier laminate 40 according to one embodiment has a laminate structure including a paper substrate 31, a water-soluble polymer layer 32, a vapor deposition layer 33, and a sealant film 34, in this order. The sealant film 34 contains a polyolefin resin. The water-soluble polymer layer 32 has oxygen barrier properties. The water-soluble polymer layer contains a water-soluble polymer. Let X be the basis weight of the paper substrate 31, and let X be the thickness of 1 m of the sealant film 34. ２ When the weight per unit area is Y, the ratio of X to Y (X / Y) is 3.7 or more and 30.0 or less. The basis weight (X) of the paper base material is 10 g / m ２ More than 100g / m ２ The following is the result.

[0116] The gas barrier laminate 40 has excellent environmental compatibility and sufficient bag-making suitability. The inventors speculate that the reason for this effect is as follows. That is, if the ratio (X / Y) is less than 3.7, the strength of the gas barrier laminate is insufficient and breaks when the laminate is transported for bag making. On the other hand, if the ratio (X / Y) is more than 30.0, the rigidity of the gas barrier laminate is too high, which hinders transportation of the gas barrier laminate. The gas barrier laminate 40 has a paper substrate basis weight (X) of 10 g / m ２ More than 100g / m ２or less, and the ratio (X / Y) is 3.7 or more. As a result, the gas barrier laminate 40 is less likely to break during transport and has excellent environmental suitability. Furthermore, the gas barrier laminate 40 has a ratio (X / Y) of 30.0 or less. As a result, the gas barrier laminate 40 has sufficient transportability. As a result, the gas barrier laminate 40 has excellent environmental suitability and sufficient bag-making suitability.

[0117] The gas barrier laminate 40 also includes a water-soluble polymer layer 32 located between the paper substrate 31 and the sealant film 34. This allows the paper substrate 31 and the sealant film 34 to be easily peeled off with water or the like. This tends to make the gas barrier laminate 40 highly recyclable. Furthermore, as will be described later, the gas barrier laminate 40 is manufactured without using a water-insoluble adhesive, and has little residual solvent and solvent odor, so it tends to have excellent packaging odor resistance and food hygiene.

[0118] The gas barrier laminate may have a laminate structure including, in this order, a paper substrate, a barrier coating layer, an adhesive layer, a vapor deposition layer, and a sealant film. Compared to gas barrier laminates having such a laminate structure, the gas barrier laminate 40 tends to be less prone to wrinkling.

[0119] The gas barrier laminate 40 also includes a vapor deposition layer 33 on the surface of the sealant film 34. This tends to suppress the occurrence of defects in the vapor deposition layer 33 due to unevenness in the paper substrate 31, compared to when the vapor deposition layer 33 is provided on the paper substrate 31. As a result, the gas barrier laminate 40 tends to have excellent gas barrier properties. The gas barrier laminate 40 also includes a sealant film. This tends to improve flex resistance, compared to when the sealant layer is a film formed by wet coating.

[0120] The ratio (X / Y) is preferably 7.0 or more, and more preferably 16.5 or more. This makes the gas barrier laminate 40 more environmentally friendly, and also makes it possible to further increase the bag-making speed and wet lamination processing speed, which tends to improve productivity. The ratio (X / Y) may be 3.7 or more and 30.0 or less, 7.0 or more and 30.0 or less, or 16.5 or more and 30.0 or less.

[0121] Each layer of the gas barrier laminate 40 will be described in detail below.

[0122] [Paper substrate] The paper substrate 31 is not particularly limited, and may be appropriately selected depending on the application of the packaging bag to which the gas barrier laminate 40 is applied. There are no particular limitations on the paper substrate 31 as long as it is made primarily of plant-derived pulp. Specific examples of the paper substrate 31 include fine paper, special fine paper, coated paper, art paper, cast-coated paper, imitation paper, kraft paper, and glassine paper. The density of the paper substrate 31 is 0.7 g / cm ３ The thickness of the paper substrate 31 may be, for example, 30 μm or more and 100 μm or less, or 30 μm or more and 70 μm or less.

[0123] The basis weight (X) of the paper base material is preferably 30 g / m because it tends to be more environmentally friendly and improves the bag-making speed and lamination speed. ２ It is preferable that the weight is 40 g / m or more. ２ The basis weight (X) of the paper substrate is preferably 80 g / m or more, since this tends to improve the heat sealability during bag production and increase the bag production speed. ２ Preferably, it is 70 g / m or less. ２ The basis weight (X) of the paper substrate is preferably 10 g / m or less. ２ More than 100g / m ２ Below, 10g / m ２ 80g / m or more ２ Below, 10g / m ２ 70g / m or more ２ Below, 30g / m ２ More than 100g / m ２ Below, 30g / m ２ 80g / m or more ２ Below, 30g / m２ 70g / m or more ２ Below, 40g / m ２ More than 100g / m ２ Below, 40g / m ２ 80g / m or more ２ or less than 40 g / m ２ 70g / m or more ２ It may be the following:

[0124] The paper substrate 31 may have a coating layer at least on the side that contacts the water-soluble polymer layer 32. The coating layer can prevent the water-soluble polymer layer 32 from penetrating into the paper and also serve to fill in unevenness in the paper. The coating layer may contain, for example, various copolymers such as styrene-butadiene, styrene-acrylic, and ethylene-vinyl acetate copolymers, polyvinyl alcohol resin, cellulose resin, paraffin (wax), etc. as binder resin, and may also contain clay, kaolin, calcium carbonate, talc, mica, etc. as filler.

[0125] The thickness of the coating layer may be, for example, 1 to 10 μm, or 3 to 8 μm.

[0126] The mass ratio of the paper substrate 31 may be 75 mass% or more, preferably 80 mass% or more, more preferably 85 mass% or more, and even more preferably 90 mass% or more, based on the entire gas barrier laminate. When the mass ratio of the paper substrate is in this range, the amount of plastic material used can be sufficiently reduced, the gas barrier laminate as a whole can be said to be made of paper, and recyclability is excellent.

[0127] [Water-soluble polymer layer] The water-soluble polymer layer 32 has oxygen barrier properties. Here, the water-soluble polymer layer 32 has oxygen barrier properties if the oxygen transmission rate (OTR) of the water-soluble polymer layer measured under conditions of 23°C and 50% relative humidity using an oxygen transmission rate measuring device ("OX-TRAN2 / 21" manufactured by MOCON Co., Ltd.) is 50 cc / m or more, in accordance with JIS K7126-2 (2006). ２ / day / atm.

[0128] The content of the water-soluble polymer may be 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, 97% by mass or more, or 100% by mass based on the total amount of the water-soluble polymer layer 32.

[0129] Examples of water-soluble polymers include polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH). A polymer is said to be water-soluble if it has a large molecular weight and is a molecule that has the property of being soluble in water. When a water-soluble polymer dissolves in water, it forms a hydrogel that encloses a large amount of water around the molecule, which tends to significantly increase the viscosity of the aqueous solution. To be water-soluble, the water-soluble polymer preferably has a degree of polymerization of 2000 or less and a degree of saponification of 80% or more. From the viewpoint of easily achieving both barrier properties and film-forming properties, it is preferable that the degree of polymerization is 400 or more and the degree of saponification is 80% or more.

[0130] Examples of PVA include resins obtained by homopolymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl versatate, followed by saponification. The PVA may also be a modified PVA that has been copolymerized or post-modified. The modified PVA can be obtained, for example, by copolymerizing a vinyl ester with an unsaturated monomer copolymerizable with the vinyl ester, followed by saponification. Examples of unsaturated monomers copolymerizable with vinyl esters include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxy group-containing α-olefins such as 3-buten-1-ol, 4-pentyn-1-ol, and 5-hexen-1-ol; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; diacetone acrylamide, acrylic acid, and the like. olefin sulfonic acids such as ethylene sulfonic acid, allyl sulfonic acid, and methallyl sulfonic acid; vinyl compounds such as alkyl vinyl ethers, dimethyl allyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2,2-dialkyl-4-vinyl-1,3-dioxane, glycerin monoallyl ether, and 3,4-diacetoxy-1-butene; vinylidene chloride, 1,4-diacetoxy-2-butene, and vinylene carbonate.

[0131] The degree of polymerization of PVA is, for example, 300 to 3000. If the degree of polymerization is 300 or more, the barrier property is less likely to decrease, and if it is 3000 or less, the viscosity does not become too high and sufficient coating suitability tends to be obtained. The saponification degree of PVA may be 90 mol% or more, 95 mol% or more, or 99 mol% or more. In addition, the saponification degree of PVA may be 100 mol% or less, or 99.9 mol% or less. The polymerization degree and saponification degree of PVA can be measured in accordance with the method described in JIS K 6726 (1994).

[0132] Examples of commercially available PVA products include Poval and Exeval manufactured by Kuraray Co., Ltd., and the JF series manufactured by Nippon Vinyl Acetate & Poval Co., Ltd.

[0133] EVOH is generally obtained by saponifying a copolymer of ethylene and an acid vinyl ester such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, or vinyl versatate.

[0134] The degree of polymerization of EVOH is, for example, 300 to 3000. If the degree of polymerization is 300 or higher, the barrier property is less likely to decrease, and if it is 3000 or lower, the viscosity does not become too high and sufficient coatability tends to be obtained. The saponification degree of the vinyl ester component of EVOH may be 90 mol% or higher, 95 mol% or higher, or 99 mol% or higher. The saponification degree of EVOH may be 100 mol% or lower, or 99.9 mol% or lower. The saponification degree of EVOH is determined by nuclear magnetic resonance (1H-NMR) measurement, from the peak area of ​​hydrogen atoms contained in the vinyl ester structure and the peak area of ​​hydrogen atoms contained in the vinyl alcohol structure.

[0135] The ethylene unit content of EVOH is 10 mol% or more, more preferably 15 mol% or more, even more preferably 20 mol% or more, and particularly preferably 25 mol% or more. The ethylene unit content of EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and even more preferably 50 mol% or less. When the ethylene unit content is 10 mol% or more, good gas barrier properties or dimensional stability can be maintained under high humidity conditions. On the other hand, when the ethylene unit content is 65 mol% or less, good gas barrier properties can be achieved. The ethylene unit content of EVOH can be determined by NMR.

[0136] An example of a commercially available EVOH product is Soarnol manufactured by Kuraray Co., Ltd.

[0137] The water-soluble polymer layer 32 may contain other components in addition to the polyolefin and polyvinyl alcohol resins described above, such as resins of polyolefins other than the polyolefins described above, polyacrylics, polyesters, polyurethanes, polyethyleneimines, polylactic acids, polyamides, starch and its derivatives, and cellulose derivatives, as well as additives such as silane coupling agents, organic titanates, glycerin, glycols, casein, and waxes.

[0138] The thickness of the water-soluble polymer layer 32 may be, for example, 0.1 μm or more, 1 μm or more, 20 μm or less, 10 μm or less, or 5 μm or less. If the thickness of the water-soluble polymer layer 32 is 0.1 μm or more, more stable barrier properties can be ensured. Furthermore, if the thickness of the water-soluble polymer layer 32 is 20 μm or less, the gas barrier laminate 40 will have better environmental compatibility.

[0139] [Vapor-Deposited Layer] The vapor-deposited layer 33 is a layer formed by vapor-depositing a metal or an inorganic compound. The vapor-deposited layer 33 is provided on the surface of the sealant film 34 so as to be in contact with the sealant film 34.

[0140] The vapor deposition layer 33 may be obtained by vapor deposition of aluminum, or may be aluminum oxide (AlO ｘ ), silicon oxide (SiO ｘ ) etc.

[0141] The thickness of the vapor-deposited layer 33 may be appropriately set depending on the intended use, but may preferably be 10 nm or more, 30 nm or more, 50 nm or more, or 300 nm or less, 100 nm or less, 80 nm or less. Setting the thickness of the vapor-deposited layer 33 to 10 nm or more makes it easy to ensure sufficient continuity of the vapor-deposited layer 33, and setting the thickness to 300 nm or less makes it easy to sufficiently suppress the occurrence of curling and cracking, and to easily achieve sufficient gas barrier performance and flexibility.

[0142] 1 m of the deposition layer 33 ２ The weight per 1m of sealant film 34 is ２Based on the weight (Y) per unit area, the content may be 20.1 wt % or less, 14.9 wt % or less, or 11.2 wt % or less.

[0143] The deposition layer 33 is preferably formed by a vacuum deposition method from the viewpoint of oxygen gas barrier performance and film uniformity. While known deposition methods include vacuum deposition, sputtering, and chemical vapor deposition (CVD), vacuum deposition is preferred due to its high deposition rate and high productivity. Among vacuum deposition methods, electron beam heating is particularly effective because it allows for easy control of the deposition rate via the irradiation area and electron beam current, and allows for rapid heating and cooling of the deposition material.

[0144] [Sealant Film] The sealant film 34 contains a polyolefin resin. Examples of polyolefin resins that can be used include ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), high-density polyethylene resin (HDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer; and mixtures thereof. Polypropylene resin is preferred as the polyolefin resin. Due to its high rigidity, the gas barrier laminate 40 tends to have even better bag-making suitability.

[0145] The content of the polyolefin resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film. The content of the polyethylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film. The content of the polypropylene resin may be 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or even 100% by mass, based on the total amount of the sealant film.

[0146] Examples of resins other than polyolefin resins include polyester resins, polylactic acid, and polybutylene succinate.

[0147] 1m of sealant film ２ The weight per unit area (Y) is 3.0 g / m ２ or more, and ２ It may be the following:

[0148] The sealant film may be unstretched, uniaxially stretched, or biaxially stretched.

[0149] A biaxially oriented polypropylene resin film can be suitably used as the sealant film. A biaxially oriented polypropylene resin film requires heat sealing at high temperatures. In particular, when paper is used as the substrate, the thickness of the paper can prevent heat from being transferred to the film during bag formation, resulting in insufficient sealing. However, the gas barrier laminate 40 has a ratio (X / Y) of 3.7 or more and 30.0 or less. This means that the gas barrier laminate 40 tends to achieve sufficient heat sealing properties while maintaining transportability, even when a biaxially oriented polypropylene resin film is used.

[0150] The thickness of the sealant layer is preferably 4 μm or more from the viewpoint of durability against heat when forming the vapor deposition layer, and is preferably 15 μm or less in order to further reduce the amount of plastic material used.

[0151] Although the gas barrier laminate according to one embodiment of the present disclosure has been described in detail above, the gas barrier laminate according to the present disclosure is not limited to the above embodiment. For example, the gas barrier laminate according to the present disclosure may include other layers in addition to the paper substrate 31, the water-soluble polymer layer 32, the vapor deposition layer 33, and the sealant film 34.

[0152] When the gas barrier laminate has another layer between the vapor deposition layer 33 and the sealant film 34, ２ The weight per 1m of sealant film 34 is ２Based on the weight (Y) per unit area, the content may be 20.1 wt % or less, 14.9 wt % or less, or 11.2 wt % or less.

[0153] <Method for Producing Gas Barrier Laminate> The gas barrier laminate is produced, for example, by a method for producing a gas barrier laminate including the following steps (A) to (C).

[0154] Step (A): A step of preparing a first laminate including a sealant film 34 and a vapor deposition layer 33. Step (B): A step of applying a composition containing a water-soluble polymer and water to the surface of the first laminate on the vapor deposition layer 33 side or to the surface of the paper substrate. Step (C): A step of bonding the first laminate and the paper substrate 31 together via the composition so that the vapor deposition layer 33 and the paper substrate 31 face each other, and drying the composition to form a water-soluble polymer layer and obtain a gas barrier laminate.

[0155] The gas barrier laminate may have a laminate structure comprising, in this order, a paper substrate, a barrier coating layer, an adhesive layer, a vapor deposition layer, and a sealant film. Compared to gas barrier laminates having such a laminate structure, the method for producing a gas barrier laminate according to this embodiment tends to be more productive because it can omit the dry lamination and aging steps for forming the adhesive layer. Furthermore, in a gas barrier laminate comprising a paper substrate, a barrier coating layer, an adhesive layer, a vapor deposition layer, and a sealant film, an adhesive is applied to the vapor deposition layer side surface of the laminate comprising the vapor deposition layer and the sealant film, and the laminate is then dried before being laminated to the paper substrate. On the other hand, in the method for producing a gas barrier laminate according to this embodiment, the first laminate and the paper substrate 31 are laminated together via a composition, and the composition is then dried. Therefore, the paper substrate serves as a support, which tends to suppress thermal shrinkage and the occurrence of wrinkles.

[0156] The content of the water-soluble polymer in the composition may be 5 to 95% by mass based on the total amount of the composition. The content of water in the composition may be 10 to 90% by mass based on the total amount of the composition. The temperature at which the composition is dried may be 70 to 150°C.

[0157] <Packaging Bag> Fig. 5 is a perspective view showing a gusseted bag 50 made of a gas barrier laminate 40. A packaging bag is produced by sealing the opening at the top of the gusseted bag 50. The gusseted bag 50 has portions where the gas barrier laminate 40 is folded (folded portions B1, B2). Folded portion B1 is a portion where the gas barrier laminate 40 is folded in a valley direction when viewed from the innermost layer side, while folded portion B2 is a portion where the gas barrier laminate 40 is folded in a mountain direction when viewed from the innermost layer side.

[0158] The packaging bag may be formed into a bag shape by folding one gas barrier laminate in half so that the sealant films 34 face each other, then folding it appropriately into the desired shape and heat sealing it, or may be formed into a bag shape by stacking two gas barrier laminates so that the sealant films 34 face each other, and then heat sealing it.

[0159] In the packaging bag according to this embodiment, the heat seal strength may be 2 N or more, or may be 10 N or more. The upper limit of the heat seal strength is not particularly limited, but may be, for example, 20 N or less.

[0160] The packaging bag can contain contents such as food, medicine, etc. It is particularly suitable for containing food such as sweets. The packaging bag according to this embodiment can maintain high gas barrier properties even when it has a shape with a folded portion.

[0161] In this embodiment, a gusset bag is given as an example of a packaging bag, but the gas barrier laminate according to this embodiment may be used to produce, for example, a pillow bag, a three-side seal bag or a standing pouch.

[0162] First Consideration The first invention group of the present disclosure will be described in more detail below based on examples and comparative examples, but the present disclosure is not limited to the following examples.

[0163] <Preparation of packaging material> (Example 1-1) A biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 3.3 μm, total thickness: 4 μm) was prepared as a sealant film, with a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin. An Al vapor-deposited layer with a thickness of 140 nm was formed on the core layer of the sealant film using a roll-to-roll induction heating vacuum vapor deposition device. A paper substrate with a basis weight of 30 g / m ２ Kraft paper of this size was used, and Takelac PP6263 / Takenate A50 manufactured by Mitsui Chemicals was used as the adhesive for the adhesive layer. The adhesive was applied to the surface of the Al vapor-deposited layer of the sealant film using a dry laminator, and the coating was dried. The Al vapor-deposited layer and the paper substrate were attached via the dried coating, resulting in a dry laminate, to obtain a laminate. The laminate was aged at 50°C for 4 days. This resulted in the easy-open packaging material of Example 1-1.

[0164] (Examples 1-2 and 1-3) As shown in Table 1, the paper substrate had a basis weight of 60 g / m ２ or 100 g / m ２ Easy-open packaging materials of Examples 1-2 and 1-3 were obtained in the same manner as in Example 1-1, except that the kraft paper of Example 1-2 was used.

[0165] (Example 1-4) An easy-open packaging material of Example 1-4 was obtained in the same manner as in Example 1-1, except that a biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 7.3 μm, total thickness: 8 μm) having a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin was used as the sealant film.

[0166] (Examples 1-5 and 1-6) As shown in Table 1, the paper substrate was a paper sheet having a basis weight of 60 g / m ２ or 100 g / m ２ Easy-open packaging materials of Examples 1-5 and 1-6 were obtained in the same manner as in Example 1-4, except that the kraft paper of Example 1-4 was used.

[0167] (Example 1-7) As a sealant film, a biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 11.3 μm, total thickness: 12 μm) was used, in which the skin layer was made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and the core layer was made of a homopolypropylene resin, and the paper substrate had a basis weight of 40 g / m ２ An easy-open packaging material of Example 1-7 was obtained in the same manner as in Example 1-1, except that the kraft paper of Example 1-1 was used.

[0168] (Examples 1-8 and 1-9) As shown in Table 1, the paper substrate was a paper sheet having a basis weight of 60 g / m ２ or 100 g / m ２ The easy-open packaging materials of Examples 1-8 and 1-9 were obtained in the same manner as in Example 1-7, except that the kraft paper of Example 1-8 was used.

[0169] (Example 1-10) An easy-open packaging material of Example 1-10 was obtained in the same manner as in Example 1-2, except that a biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 17.3 μm, total thickness: 18 μm) having a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin was used as the sealant film.

[0170] (Examples 1-11) As a paper substrate, a basis weight of 100 g / m ２ An easy-open packaging material of Example 1-11 was obtained in the same manner as in Example 1-10, except that the kraft paper of Example 1-11 was used.

[0171] (Example 1-12) An easy-open packaging material of Example 1-12 was obtained in the same manner as in Example 1-2, except that a biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 7.3 μm, total thickness: 8 μm) in which a skin layer was made of an ethylene-propylene random copolymer (ethylene content: 6 mol%) and a core layer was made of a homopolypropylene resin was used as the sealant film.

[0172] (Example 1-13) An easy-open packaging material of Example 1-13 was obtained in the same manner as in Example 1-2, except that a biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 7.3 μm, total thickness: 8 μm) in which a skin layer was made of an ethylene-propylene random copolymer (ethylene content: 0.5 mol%) and a core layer was made of a homopolypropylene resin was used as the sealant film.

[0173] Example 1-14 An easy-open packaging material of Example 1-14 was obtained in the same manner as in Example 1-2, except that a biaxially stretched OPP film (total thickness 8 μm) made of homopolypropylene resin was used as the sealant film.

[0174] Example 1-15 An easy-open packaging material of Example 1-15 was obtained in the same manner as in Example 1-2, except that a high-density polyethylene film (total thickness 10 μm) was used as the sealant film.

[0175] (Example 1-16) A biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 3.3 μm, total thickness: 4 μm) was prepared as a sealant film, with a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin. A polyvinyl alcohol aqueous solution was applied to the core layer of the sealant film using a gravure coater, and the coating was dried to form a barrier coat layer with a dry thickness of 1 μm. A roll-to-roll induction heating vacuum deposition device was used to form an Al vapor deposition layer with a thickness of 140 nm on the barrier coat layer. A paper substrate with a basis weight of 60 g / m was used. ２ Kraft paper of this size was prepared, and Takelac PP6263 / Takenate A50 manufactured by Mitsui Chemicals was used as the adhesive for the adhesive layer. The adhesive was applied to the surface of the Al vapor-deposited layer of the sealant film using a dry laminator, and the coating was dried. The Al vapor-deposited layer and the paper substrate were attached via the dried coating, resulting in a dry laminate, to obtain a laminate. The laminate was aged at 50°C for 4 days. This resulted in the easy-open packaging material of Example 1-16.

[0176] (Example 1-17) A biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 3.3 μm, total thickness: 4 μm) was prepared as a sealant film, with a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin. A 140 nm thick Al vapor-deposited layer was formed on the skin layer of the sealant film using a roll-to-roll induction heating vacuum deposition device. A polyvinyl alcohol aqueous solution was applied to the Al vapor-deposited layer of the sealant film using a gravure coater, followed by drying to form a 1 μm thick barrier coat layer. A paper substrate with a basis weight of 60 g / m ２ Kraft paper of this size was used, and Takelac PP6263 / Takenate A50 manufactured by Mitsui Chemicals was used as the adhesive for the adhesive layer. The adhesive was applied to the surface of the Al vapor-deposited layer of the sealant film using a dry laminator, and the coating was dried. The Al vapor-deposited layer and the paper substrate were attached via the dried coating, resulting in a dry laminate, to obtain a laminate. The laminate was aged at 50°C for 4 days. This resulted in the easy-open packaging material of Example 1-17.

[0177] Example 1-18 An easy-open packaging material of Example 1-18 was obtained in the same manner as in Example 1-16, except that the thickness of the vapor-deposited layer was set to 65 nm.

[0178] Example 1-19 An easy-open packaging material of Example 1-19 was obtained in the same manner as in Example 1-17, except that the thickness of the vapor-deposited layer was set to 65 nm.

[0179] Comparative Example 1-1 A packaging material of Comparative Example 1-1 was obtained in the same manner as in Example 1-1, except that a non-oriented polypropylene (CPP) film (thickness: 30 μm) was used as the sealant film.

[0180] Comparative Example 1-2 A packaging material of Comparative Example 1-2 was obtained in the same manner as in Example 1-2, except that a non-oriented polypropylene (CPP) film (thickness: 30 μm) was used as the sealant film.

[0181] Comparative Example 1-3 A packaging material of Comparative Example 1-3 was obtained in the same manner as in Example 1-3, except that a non-oriented polypropylene (CPP) film (thickness: 30 μm) was used as the sealant film.

[0182] Comparative Example 1-4 A packaging material of Comparative Example 1-4 was obtained in the same manner as in Example 1-1, except that a linear low-density polyethylene (LLDPE) film (thickness: 40 μm) was used as the sealant film.

[0183] Comparative Example 1-5 A packaging material of Comparative Example 1-5 was obtained in the same manner as in Example 1-2, except that a linear low-density polyethylene (LLDPE) film (thickness: 40 μm) was used as the sealant film.

[0184] Comparative Example 1-6 A packaging material of Comparative Example 1-6 was obtained in the same manner as in Example 1-3, except that a linear low-density polyethylene (LLDPE) film (thickness: 40 μm) was used as the sealant film.

[0185] Comparative Example 1-7 A packaging material of Comparative Example 1-7 was obtained in the same manner as in Example 1-2, except that a polyethylene terephthalate (PET) film (thickness: 30 μm) was used as the sealant film.

[0186] (Comparative Example 1-8) A biaxially stretched OPP film (skin layer thickness: 0.7 μm, core layer thickness: 3.3 μm, total thickness: 4 μm) was prepared as a sealant film, with a skin layer made of an ethylene-propylene random copolymer (ethylene content: 3.2 mol%) and a core layer made of a homopolypropylene resin. The paper substrate had a basis weight of 60 g / m. ２ Kraft paper of this size was used, and Takelac PP6263 / Takenate A50 manufactured by Mitsui Chemicals was used as the adhesive for the adhesive layer. The adhesive was applied to the surface of the core layer of the sealant film using a dry laminator, and the coating was dried. The sealant film and the paper substrate were attached via the dried coating to dry laminate, thereby obtaining a laminate. The laminate was aged at 50°C for 4 days. This resulted in the easy-open packaging material of Comparative Example 1-8.

[0187] (Comparative Example 1-9) Paper (clay-coated paper, basis weight: 60 g / m ２A coating liquid containing a polyolefin resin having carboxyl groups and a salt of carboxyl groups (product name: Chemipearl S500, ionomer-based, particle size: <0.5 μm, solvent: water and IPA, manufactured by Mitsui Chemicals, Inc.) was applied to the surface of a paper sheet (paper thickness: 55 μm, clay coat thickness: 5 μm) using a bar coater and dried in an oven to form a barrier coat layer (thickness: 3 μm). Subsequently, aluminum was vapor-deposited on the barrier coat layer to form an aluminum vapor-deposited layer (thickness: 140 nm). A non-oriented polypropylene resin (CPP) film (thickness: 20 μm) was dry-laminated onto the vapor-deposited layer as a sealant film using an adhesive (product name: Takelac PP6263 / Takenate A50, urethane-based two-component type, manufactured by Mitsui Chemicals, Inc.) to obtain a packaging material. The adhesive layer had a thickness of 2 μm.

[0188] Comparative Example 1-10: A barrier coat layer was formed on the surface of paper, and an aluminum vapor-deposited layer was formed on the barrier coat layer in the same manner as in Comparative Example 1-9. A coating liquid containing a polyolefin resin having a carboxyl group and a carboxyl group salt (product name: Chemipearl S500, ionomer-based, particle size: <0.5 μm, solvent: water and IPA, manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the vapor-deposited layer using a bar coater and dried in an oven to form an overcoat layer (thickness: 3 μm). A non-oriented polypropylene resin (CPP) film (thickness: 20 μm) was dry-laminated onto the overcoat layer as a sealant film using an adhesive (product name: Takelac PP6263 / Takenate A50, urethane-based two-component type, manufactured by Mitsui Chemicals, Inc.) to obtain a packaging material. The adhesive layer had a thickness of 2 μm.

[0189] Comparative Example 1-11 A barrier coat layer was formed on the surface of paper, and an AL vapor-deposited layer was formed on the barrier coat layer in the same manner as in Comparative Example 1-9. A coating liquid containing a polyolefin resin having a carboxyl group and a carboxyl salt (product name: Chemipearl S500, ionomer-based, particle size: <0.5 μm, solvent: water and IPA, manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the vapor-deposited layer using a bar coater, and the resulting mixture was dried in an oven to form a sealant film (thickness: 3 μm), thereby obtaining a packaging material.

[0190] Comparative Example 1-12 A packaging material was obtained in the same manner as in Comparative Example 1-9, except that a barrier coat layer was formed using a polyvinyl alcohol resin (saponification degree: 98%, polymerization degree: 500) instead of the coating liquid containing a polyolefin resin having a carboxyl group and a salt of a carboxyl group.

[0191] Comparative Example 1-13 A packaging material of Comparative Example 1-13 was obtained in the same manner as in Comparative Example 1-9, except that the thickness of the vapor-deposited layer was set to 65 nm.

[0192] Comparative Example 1-14 A packaging material of Comparative Example 1-14 was obtained in the same manner as in Comparative Example 1-10, except that the thickness of the vapor-deposited layer was set to 65 nm.

[0193] The packaging materials of the Examples and Comparative Examples were evaluated as follows.

[0194] <Bag-making suitability> Using the packaging materials obtained in each example, three-sided pouches (height: 10 cm, width: 7.7 cm) were made using a bag-making machine manufactured by Taisei Lamic Co., Ltd. The bag-making speed was 45 bags / minute. The results are shown in the table, with "A" indicating that packaging bags could be made and "B" indicating that they could not be made. In addition, for packaging materials that could be used to make packaging bags, the maximum bag-making speed at which no breakage or transport problems occurred was measured. The maximum value was evaluated according to the following criteria. The results are shown in the table.

[0195] (Criteria) A: The maximum bag-making speed is 90 bags / minute or more. B: The maximum bag-making speed is 50 bags / minute or more but less than 90 bags / minute. C: The maximum bag-making speed is less than 50 bags / minute.

[0196] <Evaluation of tearability> The tearability was evaluated using the three-sided pouches produced in the bag-making suitability evaluation. Five evaluators were randomly selected from 10 male and 10 female evaluators, and the selected evaluators tore the three-sided pouches and evaluated the tearability according to the following criteria. The three-sided pouches were torn in the direction along the paper flow direction in the papermaking process (MD) and the direction perpendicular to the paper flow direction in the papermaking process (CD). The worst evaluation result among the selected evaluators was taken as the evaluation result for that packaging material.

[0197] (Evaluation criteria) A: Easily torn and no stretching of the sealant film was observed B: Able to tear but stretching of the sealant film was observed C: Cannot be torn

[0198] <Gas Barrier Properties> The oxygen transmission rate (OTR) of the packaging material obtained in each example was measured in accordance with JIS K-7126-2 using an oxygen transmission rate measuring device (manufactured by MOCON, product name: OX-TRAN 2 / 22) at a temperature of 30°C and a relative humidity of 70%. Furthermore, a 1500 g roller was rolled at a speed of 300 mm / min, and a crease was made in the packaging material parallel to the MD so that the packaging material formed a valley fold (with the sealant film facing outward) when viewed from the paper substrate side. The oxygen transmission rate of the crease of the packaging material after opening was measured. The measurement results were evaluated according to the following criteria, with a rating of "B" or higher being considered good. The results are shown in the table.

[0199] (Standard) A: 25cc / (m ２ ・day・atm) B: 25cc / (m ２ ・day・atm) or more 50cc / (m ２ ・day・atm) less than C: 50cc / (m ２ ・day・atm) or more

[0200] <Complex Elastic Modulus> The composite elastic modulus of the surface of the sealant film of each packaging material was measured by nanoindentation. A Hysitron TI-Premier (trade name) manufactured by Bruker Japan Co., Ltd. was used as the measuring device. A Berkovich-type diamond indenter manufactured by Bruker Japan Co., Ltd. was used as the indenter. Measurement by nanoindentation was performed in displacement control mode, with the indentation being performed at a rate of 30 nm / sec to a depth of 30 nm, followed by holding at the maximum depth for 1 second and then unloading at a rate of 30 nm / sec. Measurement was performed by nanoindentation at 20 designated points spaced at intervals of 1 μm or more on the main surface of the sealant film on the side opposite the paper substrate (the innermost layer side).

[0201] The composite elastic modulus was calculated by first testing a standard sample of fused quartz and calibrating the relationship between the contact depth and the projected contact area between the indenter and the sample.Then, the unloading curve in the 60-95% range relative to the maximum load during unloading was analyzed using the Oliver-Pharr method, and the composite elastic modulus was calculated.

[0202] For the packaging materials obtained in each example, the mass ratio of the paper substrate based on the entire packaging material was measured. The results are shown in the table.

[0203]

[0204]

[0205]

[0206] Second Consideration The second invention group of the present disclosure will be explained in more detail below based on examples and comparative examples, but the present disclosure is not limited to the following examples.

[0207] [Production of Gas Barrier Laminate] (Examples 2-1 to 2-30) Sealant films of the material, thickness, density, and weight shown in Table 4 were prepared as sealant films for each Example. Aluminum was vapor-deposited on one surface of the sealant film. This resulted in a first laminate with an aluminum vapor-deposited layer (thickness: 140 nm) formed on the sealant film. Paper substrates of the basis weights shown in Table 4 were prepared as paper substrates for each Example. The first laminate and the paper substrate were then placed together with an oxygen-barrier water-soluble polymer agent (manufactured by Kuraray Co., Ltd., product name: HR-3010, coating amount: 2.5 g / m) so that the vapor-deposited layer of the first laminate faced the paper substrate. ２ ) was used to bond the laminated sheets together by wet lamination, thereby obtaining a gas barrier laminate.

[0208] In Table 4, a 12 μm thick sealant film made of OPP (biaxially oriented polypropylene resin) called Torayfan manufactured by Toray Industries, Inc. was used. In Table 4, a 9 μm thick sealant film made of HDPE (high density polyethylene resin) made by Ube Film Co., Ltd. was used.

[0209] (Comparative Examples 1 to 3) Sealant films of the material, thickness, density, and weight shown in Table 4 were prepared as sealant films for each comparative example. Aluminum was vapor-deposited on one surface of the sealant film. This resulted in a first laminate with an aluminum vapor-deposited layer (thickness: 140 nm) formed on the sealant film. Paper substrates of the basis weights shown in Table 4 were prepared as paper substrates for each comparative example. The first laminate and the paper substrate were bonded together with an adhesive (manufactured by Mitsui Chemicals, Inc., product name: base agent Takelac PP6263 / curing agent Takenate A50, application amount: 3 g / m) so that the vapor-deposited layer of the first laminate faced the paper substrate. ２ ) to obtain a gas barrier laminate.

[0210] Comparative Example 4 A sealant film having the material, thickness, density, and weight shown in Table 4 was prepared. A paper substrate having the basis weight shown in Table 4 was prepared. The sealant film and the paper substrate were bonded together with a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: base agent Takelac PP6263 / curing agent Takenate A50, application amount: 3 g / m ２ ) to obtain a gas barrier laminate.

[0211] (Comparative Example 5) A paper substrate having the basis weight shown in Table 4 was prepared as the paper substrate. Aluminum was vapor-deposited on one surface of the paper substrate. This resulted in a first laminate having an aluminum vapor-deposited layer (thickness: 140 nm) formed on the paper substrate. A sealant film having the material, thickness, density, and weight shown in Table 4 was prepared as the sealant film. The first laminate and the sealant film were bonded together with a two-component adhesive (manufactured by Mitsui Chemicals, Inc., product name: base agent Takelac PP6263 / curing agent Takenate A50, application amount: 3 g / m) so that the vapor-deposited layer of the first laminate faced the sealant film. ２ ) to obtain a gas barrier laminate.

[0212] [Gas barrier properties] The oxygen transmission rate (OTR) of the gas barrier laminate obtained in each example was measured in accordance with JIS K-7126-2 using an oxygen transmission rate measuring device (manufactured by MOCON Corporation, trade name: OX-TRAN 2 / 22) under conditions of a temperature of 23°C and a relative humidity of 50%. The measurement results were evaluated according to the following criteria, with a rating of "B" or higher being considered good.

[0213] (Standard) A: 25cc / (m ２ ・day・atm) B: 25cc / (m ２ ・day・atm) or more 50cc / (m ２ ・day・atm) less than C: 50cc / (m ２ ・day・atm) or more

[0214] [Bag-making suitability] Three-sided pouches (height: 10 cm, width: 7.7 cm) were made using the gas barrier laminate obtained in each example using a bag-making machine manufactured by Taisei Lamic Co., Ltd. The bag-making speed was 45 pouches / minute. The results are shown in Table 5, with "A" indicating that a packaging bag could be made and "B" indicating that it could not be made. In addition, for the gas barrier laminates for which packaging bags could be made, the maximum bag-making speed at which the gas barrier laminate could be made without breakage or transport problems was measured. The maximum value was evaluated according to the following criteria.

[0215] (Criteria) A: The maximum bag-making speed is 90 bags / minute or more. B: The maximum bag-making speed is 50 bags / minute or more but less than 90 bags / minute. C: The maximum bag-making speed is less than 50 bags / minute.

[0216] [Environmental Suitability] For the gas barrier laminate obtained in each example, the mass ratio of the paper substrate relative to the entire gas barrier laminate was measured. The measurement results were evaluated according to the following criteria.

[0217] (Criteria) A: The mass ratio of the paper base material is 85% by mass or more. B: The mass ratio of the paper base material is 75% by mass or more and less than 85% by mass. C: The mass ratio of the paper base material is less than 75% by mass.

[0218] [Separability (Recyclability)] The gas barrier laminate obtained in each example was immersed in each solvent to check whether the sealant film and the paper substrate could be separated. The separation results were evaluated according to the following criteria.

[0219] (Criteria) A: Separable with water above 95°C B: Cannot be separated with water above 95°C (separable with ester solvents such as ethyl acetate)

[0220] [Processing Suitability] Wet lamination was performed on the gas barrier laminate obtained in each example, and the maximum feed speed at which wrinkles could be avoided was measured. A wet laminator was used for wet lamination. Specifically, a roll of sealant film was attached to the first paper feed section of the wet laminator, and a roll of paper substrate was attached to the second paper feed section. The sealant film was fed from the first paper feed section, and a water-soluble polymer agent with oxygen barrier properties was applied to the sealant film by direct gravure to form a coating. The sealant film with the coating formed was attached to the paper substrate fed from the second paper feed section, and the coating was dried by passing through an oven. The measured maximum speed was evaluated according to the following criteria.

[0221] (Criteria) A: The maximum let-off speed is 200 m / min or more. B: The maximum let-off speed is 100 m / min or more and less than 200 m / min. C: The maximum let-off speed is 50 m / min or more and less than 100 m / min. D: The maximum let-off speed is less than 50 m / min.

[0222]

[0223]

[0224] Reference Signs List 1, 31...paper substrate, 2...adhesive layer, 3...barrier coat layer, 4, 33...deposited layer, 5...sealant film, 10, 15...packaging material, 20, 50...packaging bag, 32...water-soluble polymer layer, 40...gas barrier laminate. B1, B2...folded portion.

Claims

1. A packaging material having a laminated structure comprising, in this order, a paper substrate, an adhesive layer, a vapor deposition layer, and a sealant film, wherein the mass ratio of the paper substrate to the total mass of the packaging material is greater than 75 mass%, the thickness of the sealant film is 2 to 20 μm, and the sealant film contains a polyolefin resin.

2. The packaging material according to claim 1, wherein the sealant film has a composite elastic modulus measured on one main surface of the sealant film of 1.25 to 4.00 GPa.

3. The packaging material according to claim 1 or 2, wherein the polyolefin resin comprises a polypropylene resin.

4. The packaging material according to any one of claims 1 to 3, wherein the sealant film has a thickness of 4 to 15 μm.

5. The packaging material according to any one of claims 1 to 4, further comprising a barrier coating layer between the vapor deposition layer and the sealant film.

6. The packaging material according to any one of claims 1 to 5, further comprising a barrier coating layer between the paper substrate and the vapor deposition layer.

7. The packaging material according to claim 5, wherein the barrier coat layer contains a polyvinyl alcohol-based resin.

8. The packaging material according to claim 6, wherein the barrier coat layer contains a polyvinyl alcohol-based resin.

9. A packaging bag comprising the packaging material according to any one of claims 1 to 8.

10. The packaging bag according to claim 9, having a folded portion.

11. A method for producing a packaging material according to any one of claims 1 to 8, comprising the following steps 1 to 3: Step 1: forming the vapor deposition layer on the main surface of the sealant film to obtain a first laminate; Step 2: applying an adhesive to the main surface of the paper substrate, drying the resulting coating to form a dried product, thereby obtaining a second laminate; and Step 3: laminating the first laminate and the second laminate together so that the vapor deposition layer and the dried product face each other.

12. A laminated structure comprising a paper substrate, a water-soluble polymer layer having oxygen barrier properties, a vapor deposition layer, and a sealant film in this order, wherein the sealant film contains a polyolefin resin, the basis weight of the paper substrate is X, and the thickness of 1 m of the sealant film is X. ２ When the weight per unit area is Y, the ratio of X to Y (X / Y) is 3.7 or more and 30.0 or less, and X is 10 g / m ２ More than 100g / m ２ A gas barrier laminate comprising:

13. The gas barrier laminate according to claim 12, wherein the polyolefin resin comprises a polypropylene resin.

14. The gas barrier laminate according to claim 12 or 13, wherein the thickness of the sealant film is 4 μm or more and 15 μm or less.

15. The gas barrier laminate according to any one of claims 12 to 14, wherein the ratio (X / Y) is 7.0 or more and 30.0 or less.

16. The gas barrier laminate according to any one of claims 12 to 15, wherein the ratio (X / Y) is 16.5 or more and 30.0 or less.

17. The basis weight of the paper base material is 40 g / m ２ 80g / m or more ２ The gas barrier laminate according to any one of claims 12 to 16, wherein:

18. A packaging bag comprising the gas barrier laminate according to any one of claims 12 to 17.

19. A method for producing a gas barrier laminate according to any one of claims 12 to 17, comprising the following steps (A) to (C): step (A): preparing a first laminate comprising the sealant film and the vapor deposition layer; step (B): applying a composition containing a water-soluble polymer and water to the surface of the paper substrate or the surface of the vapor deposition layer side of the first laminate; and step (C): bonding the first laminate and the paper substrate together via the composition so that the vapor deposition layer and the paper substrate face each other, and drying the composition to form the water-soluble polymer layer and obtain the gas barrier laminate.

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