Gas barrier laminate

Abstract

A gas barrier laminate comprising a paper base material and, on at least one surface of the paper base material, an oxygen barrier layer and a water vapor barrier layer, in this order; wherein the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less; the water-soluble resin contains at least one compound selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more; the content of the inorganic compound is 150 parts by mass or more and 540 parts by mass or less per 100 parts by mass of the water-soluble resin; and the water vapor barrier layer contains a water-dispersible resin.

Description

[Technical Field]

[0001] The present invention relates to a gas barrier laminate. [Background technology]

[0002] Conventionally, a gas barrier laminate has been known that is configured by providing an oxygen barrier layer and a water vapor barrier layer in this order on a paper substrate in order to impart gas barrier properties (oxygen barrier properties) and water vapor barrier properties to a paper substrate.

[0003] Patent Document 1 describes a barrier laminate having a paper base material and, on at least one surface of the paper base material, a gas barrier layer and a water vapor barrier layer, in this order; the gas barrier layer contains one or more binders selected from the group consisting of water-soluble resin binders and water-dispersible resin binder 1; the water vapor barrier layer contains a layered inorganic compound, a cationic resin, and water-dispersible resin binder 2; water-dispersible resin binder 1 and water-dispersible resin binder 2 are different; the aspect ratio of the layered inorganic compound is equal to or greater than a specific value; the thickness of the layered inorganic compound is equal to or less than a specific value; and the content of the layered inorganic compound in the water vapor barrier layer is within a specific range. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6870797 Summary of the Invention [Problem to be solved by the invention]

[0005] The barrier laminate described in Patent Document 1 has room for improvement in oxygen barrier properties when the gas barrier layer contains a water-soluble resin binder, particularly when a water-based water vapor barrier layer coating is applied to the gas barrier layer. Also, when the gas barrier layer contains a water-dispersible resin binder to improve water resistance, there is an issue with disintegration when the laminate is reused.

[0006] The present invention has been made in view of the existence of the above problems, and has an object to provide a gas barrier laminate that has excellent oxygen barrier properties, water vapor barrier properties, and also excellent disintegration properties. [Means for solving the problem]

[0007] The present inventors have discovered that a gas barrier laminate comprising a paper base material and, on at least one surface of the paper base material, an oxygen barrier layer and a water vapor barrier layer, in this order, wherein the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of a specific value or less and an average particle size of a specific value or less, the water-soluble resin contains at least one selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more, the inorganic compound content being within a specific range, and the water vapor barrier layer contains a water-dispersible resin, thereby achieving excellent oxygen barrier property and water vapor barrier property, as well as excellent disintegration property. That is, the present invention provides the following: <1> ~ <18> Regarding. <1> A gas barrier laminate comprising a paper base material and, on at least one surface of the paper base material, an oxygen barrier layer and a water vapor barrier layer, in this order; wherein the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less; the water-soluble resin contains at least one compound selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more; the content of the inorganic compound is 150 parts by mass or more and 540 parts by mass or less per 100 parts by mass of the water-soluble resin; and the water vapor barrier layer contains a water-dispersible resin. <2> the water-soluble resin contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more but less than 700, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more but less than 2500, <1> The gas barrier laminate according to claim 1. <3> In the water-soluble resin, the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more and less than 700 to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more and 2500 or less is 5:95 to 60:40. <2> The gas barrier laminate according to claim 1. <4> the water-soluble resin contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more and 500 or less, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more and 1200 or less; <1> The gas barrier laminate according to claim 1. <5> In the water-soluble resin, the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more and 500 or less to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more and 1200 or less is 5:95 to 60:40. <4> The gas barrier laminate according to claim 1. <6> the oxygen barrier layer further contains a layered inorganic compound having an aspect ratio of 80 or more, and the content of the layered inorganic compound is 25 parts by mass or less relative to 100 parts by mass of the water-soluble resin; <1> ~ <5> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <7> The inorganic compound contains kaolin. <1> ~ <6> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <8> The water-dispersible resin contains a styrene / acrylic copolymer. <1> ~ <7> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <9> The water vapor barrier layer further contains a wax. <1> ~ <8> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <10> The wax contains paraffin wax. <9> The gas barrier laminate according to claim 1. <11> The amount of the oxygen barrier layer applied is 1 g / m 2 More than 15g / m 2 Below is the <1> ~ <10> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <12> The amount of the water vapor barrier layer applied is 4 g / m2 More than 8g / m 2 Below is the <1> ~ <11> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <13> Water vapor permeability is 20g / (m 2 ·day) or less, <1> ~ <12> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <14> Oxygen permeability is 30mL / (m 2 ·day·atm) or less, <1> ~ <13> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <15> For packaging materials, <1> ~ <14> 1. The gas barrier laminate according to claim 1, wherein the gas barrier laminate is a laminate of a first type or a second type. <16> <1> ~ <15> A packaging bag comprising the gas barrier laminate according to any one of the above items. <17> <1> ~ <15> a water-soluble resin containing a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C, and a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C. <18> the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C is 5:95 to 60:40; <17> 1. A method for producing the gas barrier laminate according to claim 1. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Gas barrier laminate] The gas barrier laminate of this embodiment (hereinafter also simply referred to as "gas barrier laminate") is a gas barrier laminate comprising a paper base material and, on at least one surface of the paper base material, an oxygen barrier layer and a water vapor barrier layer, in this order; the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less; the water-soluble resin contains at least one selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more; the content of the inorganic compound is 150 parts by mass or more and 540 parts by mass or less per 100 parts by mass of the water-soluble resin; and the water vapor barrier layer contains a water-dispersible resin.

[0009]

[0013] It has been revealed that the gas barrier laminate of this embodiment comprises an oxygen barrier layer on at least one surface of a paper substrate, the oxygen barrier layer containing a water-soluble resin having a degree of saponification of a specific value or more and a specific amount of an inorganic compound having an aspect ratio and an average particle size of a specific value or less, and a water vapor barrier layer containing a water-dispersible resin on the oxygen barrier layer, thereby providing a gas barrier laminate that has excellent oxygen barrier property and water vapor barrier property as well as excellent disintegration property. The mechanism of this effect is unknown, but is presumed to be as follows. When forming a two-layer barrier layer having oxygen barrier properties, water vapor barrier properties, and heat sealability on a paper substrate, a single layer having both oxygen barrier properties and heat sealability has not yet been realized, so the second, outermost layer must have water vapor barrier properties and heat sealability. Therefore, the first layer on at least one side of the paper substrate must be an oxygen barrier layer having oxygen barrier properties. If a water-dispersible resin is added to the oxygen barrier layer to impart oxygen barrier properties to the oxygen barrier layer, the disintegration properties of the gas barrier laminate are poor when it is reused. Therefore, if a water-soluble resin is added to the oxygen barrier layer to improve disintegration properties, the oxygen barrier layer will dissolve and no longer function properly, especially when a water-based water vapor barrier layer coating is applied to the oxygen barrier layer, which tends to result in poor oxygen barrier properties. Furthermore, when a heat seal layer is provided on at least one side of the paper substrate in addition to the water vapor barrier layer and the oxygen barrier layer, the disintegration properties are further deteriorated. Therefore, by incorporating in the oxygen barrier layer on at least one surface of the paper substrate a water-soluble resin containing at least one selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a degree of saponification equal to or greater than a specific value, and a specific amount of an inorganic compound having an aspect ratio equal to or less than a specific value and an average particle size equal to or less than a specific value, the oxygen barrier layer will function appropriately even when a water-based water vapor barrier layer paint is applied, and as a result, a gas barrier laminate with excellent oxygen barrier properties and also excellent disintegration properties can be provided. Furthermore, if the content of the inorganic compound in the oxygen barrier layer is 150 parts by mass or more per 100 parts by mass of the water-soluble resin, the oxygen barrier layer will also have excellent water resistance, and even if a water-based water vapor barrier layer paint is applied onto the oxygen barrier layer, the oxygen barrier layer will not be affected by dissolution, etc., and as a result, excellent oxygen barrier properties and water vapor barrier properties will be exhibited. Furthermore, since the oxygen barrier layer is not affected by dissolution, etc., the film-forming properties of the water vapor barrier layer are improved, and as a result, excellent water vapor barrier properties will be exhibited. Furthermore, if the content of the inorganic compound in the oxygen barrier layer is 540 parts by mass or less per 100 parts by mass of the water-soluble resin, the inorganic compound can be sufficiently filled with the water-soluble resin, eliminating gaps and resulting in excellent oxygen barrier properties. Furthermore, the smoothness of the surface of the oxygen barrier layer is improved, improving the film-forming properties of the water vapor barrier layer and resulting in excellent water vapor barrier properties. The above mechanism is based on speculation, and the present invention is not limited to this.

[0010] The gas barrier laminate of this embodiment only needs to have an oxygen barrier layer and a water vapor barrier layer, in that order, on at least one surface of the paper substrate, and may also have an oxygen barrier layer and a water vapor barrier layer, in that order, on the other surface. The gas barrier laminate of this embodiment may also have multiple oxygen barrier layers and multiple water vapor barrier layers, in that order (paper substrate / oxygen barrier layer / water vapor barrier layer / oxygen barrier layer / water vapor barrier layer...), or may have multiple oxygen barrier layers and multiple water vapor barrier layers (paper substrate / oxygen barrier layer / oxygen barrier layer... / water vapor barrier layer / water vapor barrier layer...).

[0011] When the gas barrier laminate of this embodiment is used for packaging of food, etc., it is preferable that the oxygen barrier layer and the water vapor barrier layer are provided in this order on only one side of the paper substrate. With this configuration, when the gas barrier laminate of this embodiment is heat-sealed, a pouch-shaped packaging bag can be easily produced.

[0012] <Paper base material> The paper substrate used in the gas barrier laminate of this embodiment is preferably a commonly used paper whose main component is plant-derived pulp, more preferably a paper whose main component is wood pulp, and more preferably a paper whose main component is pulp that is easily dispersible in water by mechanical disintegration. Specific examples include bleached or unbleached kraft paper, fine paper, paperboard, liner paper, coated paper, one-side glazed paper, glassine paper, graphene paper, etc., and among these, bleached or unbleached kraft paper, fine paper, and one-side glazed paper are preferred. The gas barrier laminate of this embodiment uses a paper substrate, and is therefore excellent in terms of reducing environmental impact, recyclability, and ease of disposal.

[0013] (Canadian Standard Freeness (CSF)) The Canadian Standard Freeness (CSF) of the pulp constituting the paper base material, measured in accordance with JIS P 8121-2:2012, is preferably 800 mL or less, more preferably 600 mL or less, from the viewpoint of improving gas barrier property and water vapor barrier property, and the lower limit thereof is not particularly limited, but is preferably 150 mL or more. The CSF of the pulp constituting the paper base material is measured in accordance with JIS P 8121-2:2012 using a paper base material pulp disintegrated in accordance with JIS P 8220-1:2012 as a sample.

[0014] The paper base material may contain known internal additives, such as fillers such as titanium dioxide, kaolin, talc, and calcium carbonate, internal sizing agents, dry strength agents, wet strength agents, retention aids, pH adjusters, drainage aids, water-resistant agents, softeners, antistatic agents, antifoaming agents, slime control agents, dyes, and pigments.

[0015] In the papermaking of paper substrates, a known wet papermaking machine (for example, a Fourdrinier papermaking machine, a gap former papermaking machine, a cylinder papermaking machine, a short wire papermaking machine, etc.) can be appropriately selected and used. The paper layer formed by the papermaking machine is preferably transported, for example, on a felt and dried in a dryer. A multi-stage cylinder dryer may be used as a pre-dryer before drying in the dryer.

[0016] The paper substrate obtained as described above may be subjected to a surface treatment using a calendar to make the thickness and profile uniform. For the calendar treatment, a known calendaring machine can be appropriately selected and used.

[0017] (Basic weight) The basis weight of the paper substrate is preferably 20 g / m from the viewpoint of obtaining an appropriate strength (rigidity) for the gas barrier laminate and from the viewpoint of moldability. 2 More preferably, 30 g / m 2 More preferably, 40 g / m 2 and preferably 500 g / m 2Less than 400 g / m 2 More preferably, 300 g / m or less 2 More preferably, 200 g / m or less 2 More preferably, 100 g / m or less 2 The basis weight of the paper substrate is measured in accordance with JIS P 8124:2011.

[0018] (Thickness) From the viewpoints of obtaining an appropriate strength (rigidity) for the gas barrier laminate and of moldability, the thickness of the paper substrate is preferably 20 μm or more, more preferably 30 μm or more, even more preferably 40 μm or more, still more preferably 50 μm or more, and is preferably 500 μm or less, more preferably 300 μm or less, even more preferably 150 μm or less, and still more preferably 100 μm or less. The thickness of the paper substrate is measured in accordance with JIS P 8118:2014.

[0019] (density) The density of the paper substrate is preferably 0.5 g / cm from the viewpoint of obtaining an appropriate strength (rigidity) for the gas barrier laminate and from the viewpoint of moldability. 3 More preferably, 0.6 g / cm 3 More preferably, 0.7 g / cm 3 and preferably 1.2 g / cm 3 or less, more preferably 1.0 g / cm 3 The density of the paper substrate is calculated from the basis weight and thickness of the paper substrate obtained by the above-mentioned measurement method.

[0020] <Oxygen barrier layer> The oxygen barrier layer is a layer having oxygen barrier properties that particularly prevent the permeation of oxygen gas. The oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less, the water-soluble resin containing at least one selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more, and the content of the inorganic compound is 150 parts by mass to 540 parts by mass per 100 parts by mass of the water-soluble resin.

[0021] (Water-soluble resin) A water-soluble resin refers to a resin that is soluble in water. A water-soluble resin refers to a resin that dissolves at least 1 g in 100 g of water at any temperature between 0°C and 100°C. Examples of water-soluble resins include polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, cellulose derivatives, polyvinylpyrrolidone, urethane resins, polyacrylic acid and its salts, casein, and polyethyleneimine. Among these, from the viewpoint of improving oxygen barrier properties, the water-soluble resin contains at least one selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, preferably modified polyvinyl alcohol, and more preferably modified polyvinyl alcohol.

[0022] <Saponification degree> The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is 93% or more, preferably 95% or more, more preferably 96% or more, and even more preferably 97% or more, from the viewpoints of increasing crystallinity and improving oxygen barrier properties, and of suppressing the influence on the oxygen barrier layer when a water vapor barrier layer described later is provided on the oxygen barrier layer. The saponification degree of polyvinyl alcohol and modified polyvinyl alcohol is measured in accordance with JIS K 6726:1994.

[0023] ≪Viscosity average degree of polymerization≫ From the viewpoint of improving gas barrier properties, the viscosity-average degree of polymerization of polyvinyl alcohol and modified polyvinyl alcohol is preferably 100 or more, more preferably 200 or more, and even more preferably 300 or more, and from the viewpoint of ease of layer formation, it is preferably 2500 or less, more preferably 2000 or less, even more preferably 1700 or less, still more preferably 1400 or less, and even more preferably 1200 or less. For the viscosity-average degree of polymerization of polyvinyl alcohol and modified polyvinyl alcohol, if a catalog value or the like is available, the catalog value or the like may be used, or if no catalog value or the like is available, the viscosity-average degree of polymerization is measured in accordance with JIS K 6726:1994.

[0024] ≪Viscosity≫ The viscosity of polyvinyl alcohol and modified polyvinyl alcohol (4% solution at 20°C) is preferably 1 mPa·s or more, more preferably 2 mPa·s or more, even more preferably 3 mPa·s or more, and even more preferably 10 mPa·s or more, from the viewpoint of improving gas barrier properties, and is preferably 40 mPa·s or less, more preferably 35 mPa·s or less, and even more preferably 30 mPa·s or less, from the viewpoint of facilitating layer formation by keeping the viscosity of the coating solution within an appropriate range when forming a gas barrier layer by coating. The viscosity of polyvinyl alcohol and modified polyvinyl alcohol (4% solution at 20°C) may be measured in accordance with JIS K 6726:1994, if available, or may be used if no catalog value is available.

[0025] Examples of modified polyvinyl alcohols include ethylene-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, diacetone-modified polyvinyl alcohol, etc. Among these, the modified polyvinyl alcohol preferably contains at least one selected from the group consisting of ethylene-modified polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, and acetoacetyl-modified polyvinyl alcohol, more preferably contains at least one selected from the group consisting of ethylene-modified polyvinyl alcohol and carboxy-modified polyvinyl alcohol, even more preferably contains ethylene-modified polyvinyl alcohol, and even more preferably is ethylene-modified polyvinyl alcohol.

[0026] As the water-soluble resin, a commercially available product may be used, for example, modified polyvinyl alcohol such as "Exceval (trade name)" manufactured by Kuraray Co., Ltd.

[0027] From the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid, the water-soluble resin preferably contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more but less than 700, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more but 2500 or less, and more preferably contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more but 500 or less, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more but 1200 or less. In the water-soluble resin, the ratio by mass of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more but less than 700 to the mass of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more but less than 2500 (polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more but less than 700:polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 to 2500) is preferably 5:95 to 60:40, more preferably 6:94 to 55:45, even more preferably 7:93 to 40:60, and even more preferably 8:92 to 35:65, from the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid. In the water-soluble resin, the ratio by mass of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more and 500 or less to the mass of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more and 1200 or less (polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 to 500:polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 to 2500) is preferably 5:95 to 60:40, more preferably 6:94 to 55:45, even more preferably 7:93 to 40:60, and even more preferably 8:92 to 35:65, from the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid.

[0028] From the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid, the water-soluble resin preferably contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C, and more preferably contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 3 mPa·s or more and 5 mPa·s or less in a 4% aqueous solution at 20°C, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 17 mPa·s or less in a 4% aqueous solution at 20°C.

[0029] From the viewpoint of improving oxygen barrier properties and disintegration properties, the content of the water-soluble resin in the oxygen barrier layer is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, still more preferably 18% by mass or more, based on the solid content of the oxygen barrier layer, and is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and still more preferably 35% by mass or less.

[0030] From the viewpoint of improving the oxygen barrier property, the content of polyvinyl alcohol and modified polyvinyl alcohol in the water-soluble resin is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, of the solid content of the water-soluble resin, and the upper limit is not particularly limited, but is 100% by mass or less.

[0031] (Inorganic compound) In this embodiment, the inorganic compound has an aspect ratio of 50 or less and an average particle size of 3 μm or less, from the viewpoint of suppressing protrusion from the oxygen barrier layer and improving the oxygen barrier property. From the above viewpoints, the aspect ratio of the inorganic compound is preferably 2 or more, more preferably 5 or more, and preferably 45 or less, more preferably 40 or less, and even more preferably 38 or less. The aspect ratio of the inorganic compound is measured by the method described in the Examples. From the same viewpoint, the average particle size of the inorganic compound is preferably 0.1 μm or more, more preferably 0.2 μm or more, and preferably 2 μm or less, more preferably 1.5 μm or less, and even more preferably 1.2 μm or less. The average particle size of the inorganic compound is measured by the method described in the Examples.

[0032] Examples of the inorganic compound include mica, kaolin, pyrophyllite, talc, bentonite, montmorillonite, vermiculite, chlorite, septe chlorite, serpentine, stilpnomelane, etc. Among these, it is preferable to contain at least one selected from the group consisting of mica, bentonite, kaolin, and talc, it is more preferable to contain at least one selected from the group consisting of mica and kaolin, and it is even more preferable to contain kaolin.

[0033] From the viewpoint of improving the oxygen barrier property and water vapor barrier property, the content of the inorganic compound in the oxygen barrier layer is from 150 parts by mass to 540 parts by mass, preferably 160 parts by mass or more, more preferably 170 parts by mass or more, even more preferably 180 parts by mass or more, and preferably 480 parts by mass or less, more preferably 420 parts by mass or less, even more preferably 360 parts by mass or less, and still more preferably 320 parts by mass or less, relative to 100 parts by mass of the water-soluble resin.

[0034] (layered inorganic compounds) From the viewpoint of improving the oxygen barrier property, the oxygen barrier layer may further contain a layered inorganic compound having an aspect ratio of preferably 80 or more. The aspect ratio of the layered inorganic compound is more preferably 100 or more, even more preferably 300 or more, still more preferably 500 or more, even more preferably 700 or more, and even more preferably 900 or more, and the upper limit is not particularly limited, but is preferably 10,000 or less, more preferably 5,000 or less, even more preferably 3,000 or less, and even more preferably 1,500 or less. When a layered inorganic compound is contained in the oxygen barrier layer, the content of the layered inorganic compound is not particularly limited, but is preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 4 parts by mass or more, and is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, even more preferably 20 parts by mass or less, still more preferably 15 parts by mass or less, and even more preferably 13 parts by mass or less, relative to 100 parts by mass of the water-soluble resin in the oxygen barrier layer. Examples of layered inorganic compounds include mica, kaolin, pyrophyllite, talc, bentonite, montmorillonite, vermiculite, chlorite, septe chlorite, serpentine, and stilpnomelane. Among these, at least one selected from the group consisting of mica, bentonite, kaolin, and talc is preferred, at least one selected from the group consisting of mica and kaolin is more preferred, and mica is even more preferred. The layered inorganic compound contained in the oxygen barrier layer may be the same type as or different from the inorganic compound contained in the oxygen barrier layer.

[0035] In addition to the water-soluble resin, inorganic compound, and layered inorganic compound, the oxygen barrier layer may contain, as needed, appropriate additives such as pigments, dispersants, surfactants, defoamers, wetting agents, dyes, color adjusters, and thickeners.

[0036] The amount of the oxygen barrier layer applied is preferably 1 g / m2 per side in terms of solid content from the viewpoint of improving the oxygen barrier property. 2 More preferably, 1.5 g / m 2 More preferably, 2.5 g / m 2 More preferably, 3.5 g / m 2 Furthermore, when the coating amount exceeds a certain level, the oxygen barrier property reaches a plateau, so from the viewpoint of economy, it is preferably 15 g / m 2 Less than 13 g / m, more preferably 2 or less, more preferably 11 g / m 2 Less than 7 g / m 2When a paper substrate has a plurality of oxygen barrier layers on one side thereof, the amount of the oxygen barrier layers applied means the total amount of the oxygen barrier layers applied.

[0037] <Water vapor barrier layer> The water vapor barrier layer is a layer having water vapor barrier properties that prevent the transmission of water vapor. The water vapor barrier layer contains a water-dispersible resin.

[0038] (Water dispersible resin) Water-dispersible resins are resins that are not water-soluble but can be finely dispersed in water, such as emulsions or suspensions. Examples of water-dispersible resins include polyolefin resins (polyethylene, polypropylene, etc.), vinyl chloride resins, styrene resins, styrene / butadiene copolymers, styrene / acrylic copolymers, acrylonitrile / styrene copolymers, acrylonitrile / butadiene copolymers, ABS resins, AAS resins, AES resins, vinylidene chloride resins, polyurethane resins, poly-4-methylpentene-1 resins, polybutene-1 resins, vinylidene fluoride resins, vinyl fluoride resins, fluororesins, polycarbonate resins, polyamide resins, acetal resins, polyphenylene oxide resins, polyester resins (polyethylene terephthalate, polybutylene terephthalate, etc.), polyphenylene sulfide resins, polyimide resins, polysulfone resins, polyethersulfone resins, aromatic polyester resins, polyarylate resins, olefin / unsaturated carboxylic acid copolymers, and modified versions thereof. The water-dispersible resin is preferably an emulsion, and more preferably contains at least one selected from the group consisting of a styrene / butadiene copolymer, a styrene / acrylic copolymer, and an olefin / unsaturated carboxylic acid copolymer, and even more preferably contains a styrene / acrylic copolymer.

[0039] <Styrene / butadiene copolymer> Examples of the styrene / butadiene copolymer include styrene / butadiene rubber (SBR) and modified styrene / butadiene rubber (modified SBR). Examples of the modified styrene / butadiene rubber include acid-modified styrene / butadiene rubber (acid-modified SBR). As the styrene / butadiene copolymer, commercially available products may be used, such as "Nipol LX407S series (trade name)" and "Nipol LX407BP series (trade name)" manufactured by Nippon Zeon Co., Ltd.

[0040] <Styrene / acrylic copolymer> Styrene / acrylic copolymers are copolymers obtained by emulsion polymerization of styrene monomers, acrylic monomers, and, if necessary, other monomers copolymerizable therewith. Examples of styrene monomers include aromatic vinyl compounds such as styrene, α-methylstyrene, vinyltoluene, pt-butylstyrene, and chlorostyrene. Examples of acrylic monomers include unsaturated carboxylic acid monomers such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, and butenetricarboxylic acid; unsaturated polycarboxylic acid alkyl esters having at least one carboxy group such as itaconic acid monoethyl ester, fumaric acid monobutyl ester, and maleic acid monobutyl ester; and (meth)acrylic sulfonic acid monomers or salts thereof such as acrylamidopropanesulfonic acid, acrylate sulfoethyl sodium salt, and methacrylate sulfopropyl sodium salt. Examples of other monomers include (meth)acrylic acid alkyl esters (having 1 to 24 carbon atoms). The styrene monomer is preferably styrene, and the acrylic monomer is preferably acrylic acid, methacrylic acid, itaconic acid, or fumaric acid. Commercially available styrene / acrylic copolymers may be used, such as "Harbil Series C-3 (trade name)" manufactured by Daiichi Toryo Seizosho Co., Ltd., and "ACRONAL 4160 (trade name)" and "Joncryl HPB4130 (trade name)" manufactured by BASF.

[0041] <Olefin / unsaturated carboxylic acid copolymer> The olefin / unsaturated carboxylic acid copolymer is a copolymer obtained by emulsion polymerization of an olefin monomer and an unsaturated carboxylic acid monomer. Examples of the olefin monomer for the olefin / unsaturated carboxylic acid copolymer include α-olefins such as ethylene, propylene, and butylene, and among these, ethylene is preferred. The unsaturated carboxylic acid monomers in the olefin / unsaturated carboxylic acid copolymer include unsaturated carboxylic acid monomers and ester monomers of unsaturated carboxylic acids that form carboxylic acids upon hydrolysis. Examples of the unsaturated carboxylic acid monomers in the olefin / unsaturated carboxylic acid copolymer include unsaturated carboxylic acids and esters thereof, such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, itaconic acid, fumaric acid, maleic acid, and butenetricarboxylic acid; and unsaturated polycarboxylic acid alkyl esters having at least one carboxy group, such as itaconic acid monoethyl ester, fumaric acid monobutyl ester, and maleic acid monobutyl ester. The unsaturated carboxylic acid monomers constituting the olefin / unsaturated carboxylic acid copolymer may be used alone or in combination of two or more. The olefin / unsaturated carboxylic acid copolymer may also be copolymerized with a small amount of other monomers copolymerizable with the olefin and unsaturated carboxylic acid monomer. Among these, the olefin / unsaturated carboxylic acid copolymer is preferably at least one selected from the group consisting of ethylene / acrylic acid copolymers and ethylene / methacrylic acid copolymers, more preferably at least one selected from the group consisting of ethylene / acrylic acid copolymers, ethylene / methacrylic acid copolymers, ethylene / methyl acrylate copolymers, ethylene / methyl methacrylate copolymers, ethylene / ethyl acrylate copolymers, ethylene / ethyl methacrylate copolymers, ethylene / butyl acrylate copolymers, and ethylene / butyl methacrylate copolymers, and even more preferably an ethylene / acrylic acid copolymer.

[0042] Commercially available olefin / unsaturated carboxylic acid copolymers may be used, such as "Zaixen (trade name) AC" manufactured by Sumitomo Seika Chemicals Co., Ltd., which is an aqueous dispersion of ethylene / acrylic acid copolymer ammonium salt.

[0043] The olefin / unsaturated carboxylic acid copolymer preferably has a content of unsaturated carboxylic acid monomer units of 1 mol % or more, more preferably 10 mol % or more, and preferably 50 mol % or less, more preferably 30 mol % or less.

[0044] The content of the water-dispersible resin is not particularly limited, but is preferably 20 mass % or more, more preferably 50 mass % or more, even more preferably 60 mass % or more, and still more preferably 70 mass % or more of the total solid content of the water vapor barrier layer.

[0045] From the viewpoint of imparting slip properties and suppressing blocking, it is preferable that the water vapor barrier layer further contains a wax. Examples of waxes include natural waxes such as animal- or plant-derived waxes (e.g., beeswax, carnauba wax, etc.), mineral waxes (e.g., microcrystalline wax, etc.), and petroleum wax; and synthetic waxes such as polyolefin wax, paraffin wax, and polyester wax. Among these, it is preferable that the water vapor barrier layer contains at least one wax selected from the group consisting of paraffin wax, carnauba wax, and polyolefin wax, and it is more preferable that the water vapor barrier layer contains paraffin wax.

[0046] The wax content in the water vapor barrier layer is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, of the total solid content of the water vapor barrier layer.

[0047] In addition to the water-dispersible resin and wax, the water vapor barrier layer may contain appropriate additives such as dispersants, surfactants, antifoaming agents, wetting agents, dyes, color adjusters, and thickeners, as needed.

[0048] The amount of the water vapor barrier layer applied is preferably 1 g / m2 per side in terms of solid content. 2 More preferably, 3 g / m 2 More preferably, 4 g / m 2 and preferably 15 g / m 2 Less than 10 g / m, more preferably 2 or less, more preferably 8 g / m 2 When a paper substrate has multiple water vapor barrier layers on one side, the amount of water vapor barrier layers applied refers to the total amount applied.

[0049] <any layer> The gas barrier laminate may include an optional layer in addition to the paper substrate, oxygen barrier layer, and water vapor barrier layer. An example of the optional layer is a printed layer. When the optional layer includes a printed layer, it is preferable to provide the printed layer on the side of the paper substrate opposite to the side on which the oxygen barrier layer and water vapor barrier layer are provided. The printed layer preferably contains a pigment and a binder.

[0050] [Method of manufacturing gas barrier laminate] The method for producing the gas barrier laminate according to this embodiment preferably includes the step of laminating an oxygen barrier layer and a water vapor barrier layer on at least one surface of a paper substrate, and more preferably the step of laminating an oxygen barrier layer on at least one surface of the paper substrate is followed by the step of laminating a water vapor barrier layer on the oxygen barrier layer (paper substrate / oxygen barrier layer / water vapor barrier layer, paper substrate / oxygen barrier layer / water vapor barrier layer / oxygen barrier layer / water vapor barrier layer..., paper substrate / oxygen barrier layer / oxygen barrier layer... / water vapor barrier layer / water vapor barrier layer...).

[0051] The oxygen barrier layer may be formed by applying a coating liquid containing the components constituting the oxygen barrier layer described above to at least one surface of the paper substrate, by melt-extrusion laminating the components, or by preparing a film containing the components and laminating it with an adhesive, etc. Among these, it is preferable that the oxygen barrier layer is laminated by applying a coating liquid containing the components constituting the oxygen barrier layer described above.

[0052] The solvent for the coating liquid is not particularly limited, and may be water or an organic solvent such as ethanol, isopropyl alcohol, methyl ethyl ketone, or toluene. Among these, water is preferred as the dispersion medium for the coating liquid from the viewpoint of avoiding the problems associated with volatile organic solvents. The solid content of the coating liquid is not particularly limited and may be appropriately selected from the viewpoints of coatability and ease of drying, and is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. There are no particular limitations on the coating equipment used to apply the coating liquid, and known equipment may be used, such as a blade coater, a bar coater, an air knife coater, a slit die coater, a gravure coater, a microgravure coater, and a gate roll coater. The drying equipment for drying the applied coating liquid is not particularly limited, and known equipment can be used. Examples of drying equipment include a hot air dryer, an infrared dryer, and a hot plate. The drying temperature may be appropriately set taking into consideration the drying time, etc.

[0053] From the viewpoint of suppressing aggregation of the oxygen barrier layer coating solution, the water-soluble resin constituting the coating solution preferably contains a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C, and a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C, and more preferably contains a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 3 mPa·s or more and 5 mPa·s or less in a 4% aqueous solution at 20°C, and a polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 17 mPa·s or less in a 4% aqueous solution at 20°C.

[0054] In the water-soluble resins constituting the coating liquid, the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C (polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 to 6 mPa·s:polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 to 35 mPa·s) is preferably 5:95 to 60:40, more preferably 6:94 to 55:45, even more preferably 7:93 to 40:60, and even more preferably 8:92 to 35:65, from the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid. In the water-soluble resins constituting the coating liquid, the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 3 mPa·s or more and 5 mPa·s or less in a 4% aqueous solution at 20°C to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 17 mPa·s or less in a 4% aqueous solution at 20°C (polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 3 to 5 mPa·s:polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 to 17 mPa·s) is preferably 5:95 to 60:40, more preferably 6:94 to 55:45, even more preferably 7:93 to 40:60, and even more preferably 8:92 to 35:65, from the viewpoint of suppressing aggregation of the oxygen barrier layer coating liquid.

[0055] The water vapor barrier layer may be formed by applying a coating liquid containing the components constituting the water vapor barrier layer described above, by melt-extrusion laminating the components, or by preparing a film containing the components and laminating it with an adhesive or the like. Among these, the water vapor barrier layer is preferably laminated by applying a coating liquid containing the components constituting the water vapor barrier layer described above. The solvent, solids content, coating equipment, and drying equipment for the coating liquid can be appropriately selected in the same manner as for the coating liquid for the oxygen barrier layer.

[0056] The gas barrier laminate may have the above-mentioned optional layers laminated thereon in addition to the paper substrate, oxygen barrier layer, and water vapor barrier layer. The optional layers can be formed by known methods.

[0057] <Properties of gas barrier laminate> (Water vapor permeability) The lower the water vapor permeability of the gas barrier laminate, the less water vapor is transmitted, and it is preferable. Specifically, it is preferably 20 g / (m 2 ·day) or less, more preferably 18g / (m 2 ·day) or less, more preferably 16g / (m 2 ·day) or less, and even more preferably 13g / (m 2·day) or less, more preferably 11 g / (m 2 ·day) or less, and more preferably 9g / (m 2 ·day) or less. The water vapor permeability of the gas barrier laminate is measured by the method described in the examples.

[0058] (oxygen permeability) The lower the oxygen permeability of the gas barrier laminate, the less oxygen is permeated, and specifically, it is preferably 35 mL / (m 2 ·day·atm) or less, preferably 30mL / (m 2 ·day·atm) or less, more preferably 25mL / (m 2 ·day·atm) or less, and even more preferably 17mL / (m 2 ·day·atm) or less, more preferably 13mL / (m 2 ·day·atm) or less, and more preferably 10mL / (m 2 ·day·atm) or less, and even more preferably 6mL / (m 2 The oxygen permeability of the gas barrier laminate is measured by the method described in the examples.

[0059] (Heat seal peel strength) From the viewpoint of heat sealing properties and ease of production, the heat seal peel strength of the gas barrier laminate when the water vapor barrier layers are heat sealed together under conditions of 160°C, 0.2 MPa, and 1 second is preferably 1 N / 15 mm or more, more preferably 2 N / 15 mm or more, and preferably 15 N / 15 mm or less, more preferably 10 N / 15 mm or less, and even more preferably 7 N / 15 mm or less. The heat seal peel strength of the gas barrier laminate is measured by the method described in the examples.

[0060] (Disaggregation rate) From the viewpoint of improving recyclability, the disintegration rate of the gas barrier laminate is preferably 85% or more, more preferably 88% or more, and even more preferably 90% or more. The disintegration rate of the gas barrier laminate is measured by the method described in the examples.

[0061] The gas barrier laminate of this embodiment takes advantage of its excellent oxygen barrier property, water vapor barrier property and disintegrability, and is therefore suitable as a packaging material for foods, fruits, medical products, electronic components, etc. Also provided is a packaging bag made using the gas barrier laminate of this embodiment.

[0062] [Packaging bag] A packaging bag according to another embodiment of the present disclosure is a packaging bag made using the gas barrier laminate, and examples of the packaging bag include a standing pouch type, a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a palm seal type (pillow seal type), a pleated seal type, a flat bottom seal type, a square bottom seal type, and a gusset type. The packaging bag of the present embodiment may be formed by folding the gas barrier laminate or by overlapping two sheets of the gas barrier laminate and bonding the peripheral edges thereof with an adhesive to form the above-mentioned configuration, but it is preferable to fold the water vapor barrier layer of the gas barrier laminate or overlap two sheets of the gas barrier laminate so that the water vapor barrier layers face each other, and then heat-seal the peripheral edges thereof to form the above-mentioned configuration. [Example]

[0063] The features of the present invention will be explained in more detail below with reference to examples and comparative examples. The materials, amounts used, ratios, processing details, processing procedures, etc. shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be interpreted as being limited by the specific examples shown below. In the examples and comparative examples, "parts" and "%" refer to "parts by mass" and "% by mass", respectively, unless otherwise specified.

[0064] [Analysis and Evaluation] The inorganic compounds, water-soluble resins, layered inorganic compounds, and oxygen barrier layer coating solutions used in the Examples and Comparative Examples were analyzed as follows. The gas barrier laminates of the Examples and Comparative Examples were also evaluated as follows.

[0065] <Inorganic compounds and / or layered inorganic compounds> (aspect ratio) The aspect ratios of the inorganic compounds and layered inorganic compounds were determined from enlarged photographs taken with an electron microscope. Specifically, a cross-section of a laminate containing an inorganic compound and / or layered inorganic compound was enlarged using an electron microscope at a magnification that allowed for approximately 20 to 50 pigment particles to be included within the image, and the length and thickness of each pigment particle within the image were measured to calculate the aspect ratio. The average of the obtained aspect ratios was calculated and used as the aspect ratio of the inorganic compound and layered inorganic compound.

[0066] (Average particle size) The average particle size of the inorganic compound was determined as the particle size (D50) at which the cumulative value reaches 50% in the volume-based particle size distribution using a laser diffraction / scattering particle size distribution analyzer (Microtrac-Bell Corporation, product name: Microtrac MT3300EXII).

[0067] <Water-soluble resin> (Saponification degree) The degree of saponification of the water-soluble resin was measured in accordance with JIS K 6726:1994.

[0068] (Viscosity average degree of polymerization) The viscosity-average degree of polymerization of the water-soluble resin was measured in accordance with JIS K 6726:1994.

[0069] <Oxygen barrier layer coating fluid> (Percentage of aggregates) The proportion of aggregates in the oxygen barrier layer coating solution was measured using a Marlon stability tester (manufactured by SMT Corporation, product name: PM-9302MT) using a coating solution adjusted to a solids concentration of 10% by mass. Specifically, 50 g of the coating solution (as is) was rotated at 1000 rpm for 20 minutes in the Marlon stability tester under a load of 15 kg, and the resulting aggregates were filtered through a 200-mesh stainless steel wire screen, washed with water, recovered, dried in a dryer at 105°C for 30 minutes, and then their mass was measured to calculate the proportion of aggregates relative to the solids contained in 50 g of the coating solution (as is).

[0070] <Gas barrier laminate> (Water vapor permeability) The water vapor permeability of the gas barrier laminate was measured in accordance with JIS Z 0208:1976 (cup method) Method B (temperature 40±0.5°C, relative humidity 90±2%), with the water vapor barrier layer of the gas barrier laminate facing inward.

[0071] (oxygen permeability) The oxygen permeability of the gas barrier laminate was measured using an oxygen permeability measuring device (manufactured by MOCON, product name: OX-TRAN2 / 22) under conditions of 23°C and 50% RH. Specifically, an isocyanate adhesive (manufactured by DIC Corporation, a mixture of 10 parts of "Dicdry LX-500 (product name)" and 1 part of "Dicdry KW-75 (product name)") was applied to the surface of the water vapor barrier layer of the gas barrier laminate at a solid content of 4 g / m. 2 After application, the coating was dried for 10 seconds in a blower dryer set to 80°C, and a 20 μm thick unstretched polypropylene film (manufactured by Hokuetsu Chemicals Co., Ltd., product name: GP-32) was laminated to form a laminate sheet. The oxygen permeability of the laminate sheet was measured at 23°C and 50% RH in accordance with JIS K 7126-2:2006. The lower the oxygen permeability value, the better the oxygen barrier property. The unstretched polypropylene film was laminated to facilitate measurement without being affected by the unevenness of the laminate, and the unstretched polypropylene film does not affect the oxygen permeability.

[0072] (Heat seal peel strength) Two gas barrier laminates were stacked with the water vapor barrier layers facing each other and heat-sealed using a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name: TP-701-B) at 160°C, 0.2 MPa, and for 1 second. The heat-sealed test specimen was left to stand for at least 4 hours in a room at a temperature of 23°C ± 1°C and a relative humidity of 50% ± 2%. The heat-sealed test specimen was then cut to a width of 15 mm and subjected to T-peel testing at a tensile speed of 300 mm / min using a tensile tester. The maximum load recorded was taken as the heat seal peel strength.

[0073] (Disaggregation rate) A gas barrier laminate with a bone-dry mass of 50 g was cut into approximately 3 cm squares, diluted with warm water at 40°C so that the gas barrier laminate concentration was 2.5%, and disintegrated for 10 minutes at 3,000 rpm using a TAPPI standard disintegrator (Kumagaya Riki Co., Ltd.). The resulting pulp slurry was passed through a flat screen (Kumagaya Riki Co., Ltd.) equipped with a 6-cut (0.15 mm slit width) screen plate and refined in a water flow of 8.6 L / min. The undisintegrated material remaining on the screen plate was collected and dried in an oven at 105°C. The mass was measured, and the disintegration rate was calculated using the following formula: Disintegration rate (%) = {bone dry mass (g) of gas barrier laminate used in test - bone dry mass (g) of undisintegrated material} / bone dry mass (g) of gas barrier laminate used in test × 100

[0074] Example 1 <Preparation of Oxygen Barrier Layer Coating Solution> An oxygen barrier layer coating solution was prepared by adding 200 parts by mass (solids content) of a 50% aqueous dispersion of kaolin (Contour Xtreme (product name), manufactured by Shiraishi Kogyo Co., Ltd., particle size: 0.9 μm, aspect ratio: approximately 33) to 100 parts by mass (solids content) of a 10% aqueous solution of ethylene-modified polyvinyl alcohol (manufactured by Kuraray Co., Ltd., "Exceval HR-3010"; saponification degree: 99%; viscosity average degree of polymerization: 1,000; viscosity (20°C, 4% aqueous solution): 12.0-16.0 mPa·s (catalog value)). Water was then added to the mixture to bring the solids content to 10% and the mixture was stirred. <Preparation of Water Vapor Barrier Layer Coating Solution> A water vapor barrier layer coating solution was prepared by adding water to 100 parts by mass (solids content) of a paraffin-containing styrene-acrylic aqueous dispersion (manufactured by BASF Japan Ltd., "JONCRYL HPB4130 (trade name)", solids content concentration 42%) so that the solids content became 30% by mass, and stirring the mixture. <Preparation of Gas Barrier Laminate> The obtained oxygen barrier layer coating liquid was applied to a substrate having a basis weight of 50 g / m 2 , 4 g / m solids on the rough side of 66 μm thick one-sided gloss bleached kraft paper (manufactured by Oji Materia Co., Ltd., CSF after disintegration: 400 mL)2 The resulting water vapor barrier layer coating solution was applied to the oxygen barrier layer in a solids content of 6 g / m2 using a bar coater, and then dried for 20 seconds using a fan dryer set at 140°C to form an oxygen barrier layer. 2 The coating was applied using a bar coater so that the coating became as shown in Table 1, and the coating was dried for 20 seconds in a fan dryer set at 140°C to form a water vapor barrier layer, thereby obtaining a gas barrier laminate. The measurement results are shown in Table 1.

[0075] Examples 2 and 8 A gas barrier laminate was obtained in the same manner as in Example 1, except that in preparing the oxygen barrier layer coating solution, the amount of kaolin added was set to the value shown in Table 1. The measurement results are shown in Table 1.

[0076] Example 3 A gas barrier laminate was obtained in the same manner as in Example 1, except that in preparing the oxygen barrier layer coating solution, the amount of kaolin added was set to the value shown in Table 1, and the amount of oxygen barrier layer applied was set to the value shown in Table 1. The measurement results are shown in Table 1.

[0077] Examples 4 to 7 A gas barrier laminate was obtained in the same manner as in Example 3, except that the amount of the oxygen barrier layer applied was set to the value shown in Table 1. The measurement results are shown in Table 1.

[0078] Example 9 A gas barrier laminate was obtained in the same manner as in Example 7, except that the ethylene-modified polyvinyl alcohol used in preparing the oxygen barrier layer coating solution was changed to "EXCEVAL AQ-4104 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 400, viscosity (20°C, 4% aqueous solution) 3.5-4.5 mPa s (catalog value)). The measurement results are shown in Table 1.

[0079] Example 10 A gas barrier laminate was obtained in the same manner as in Example 2, except that the kaolin used in preparing the oxygen barrier layer coating solution was changed to "Kaofine 90 (trade name)" (manufactured by Shiraishi Kogyo Co., Ltd., particle size: 0.3 μm, aspect ratio: approximately 10). The measurement results are shown in Table 1.

[0080] Example 11 A gas barrier laminate was obtained in the same manner as in Example 2, except that in preparing the oxygen barrier layer coating solution, 10 parts by mass (solid content) of an aqueous dispersion of synthetic mica (manufactured by Topy Industries, Ltd., "NTS-10NC (trade name)", particle size: 19.8 μm, aspect ratio: approximately 1260) dispersed in water at a solid content of 8% was further added. The measurement results are shown in Table 1.

[0081] Example 12 A gas barrier laminate was obtained in the same manner as in Example 11, except that in preparing the oxygen barrier layer coating solution, the amount of synthetic mica added was set to the value shown in Table 1. The measurement results are shown in Table 1.

[0082] Example 13 A gas barrier laminate was obtained in the same manner as in Example 1, except that the ethylene-modified polyvinyl alcohol used in the preparation of the oxygen barrier layer coating solution was changed to 10 parts by mass (solids) of a 10% aqueous solution of "EXCEVAL AQ-4104 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 400, viscosity (20°C, 4% aqueous solution): 3.5-4.5 mPa·s (catalog value)) or 90 parts by mass (solids) of a 10% aqueous solution of "EXCEVAL HR-3010 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 1,000, viscosity (20°C, 4% aqueous solution): 12.0-16.0 mPa·s (catalog value)). The measurement results are shown in Table 2.

[0083] Examples 14 and 15 A gas barrier laminate was obtained in the same manner as in Example 13, except that the blending amounts (solid content) of a 10% aqueous solution of "EXCEVAL AQ-4104 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 400, viscosity (20°C, 4% aqueous solution): 3.5-4.5 mPa·s (catalog value)) used in the preparation of the oxygen barrier layer coating solution and the blending amounts (solid content) of a 10% aqueous solution of ethylene-modified polyvinyl alcohol "EXCEVAL HR-3010 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 1,000, viscosity (20°C, 4% aqueous solution): 12.0-16.0 mPa·s (catalog value)) used in the preparation of the oxygen barrier layer coating solution were set to the values ​​shown in Table 2. The measurement results are shown in Table 2.

[0084] Example 16 A gas barrier laminate was obtained in the same manner as in Example 1, except that the ethylene-modified polyvinyl alcohol used in preparing the oxygen barrier layer coating solution was changed to 100 parts by mass of "EXCEVAL AQ-4104 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 99%, viscosity-average degree of polymerization: 400, viscosity (20°C, 4% aqueous solution) 3.5-4.5 mPa s (catalog value)). The measurement results are shown in Table 2.

[0085] Comparative Examples 1 and 2 A gas barrier laminate was obtained in the same manner as in Example 1, except that in preparing the oxygen barrier layer coating solution, the amount of kaolin added was set to the value shown in Table 3. The measurement results are shown in Table 3.

[0086] Comparative Example 3 A gas barrier laminate was obtained in the same manner as in Example 5, except that the kaolin used in preparing the oxygen barrier layer coating solution was changed to "Barisurf HX (product name)" (manufactured by Shiraishi Kogyo Co., Ltd., particle size: 9 μm, aspect ratio: approximately 100). The measurement results are shown in Table 3.

[0087] Comparative Example 4 A gas barrier laminate was obtained in the same manner as in Example 5, except that the polyvinyl alcohol used in preparing the oxygen barrier layer coating solution was changed to "PVA-217 (trade name)" (manufactured by Kuraray Co., Ltd., degree of saponification: 88%, viscosity-average degree of polymerization: 1,700, viscosity (20°C, 4% aqueous solution): 20.5-24.5 mPa s (catalog value)). The measurement results are shown in Table 3.

[0088] Comparative Example 5 A gas barrier laminate was obtained in the same manner as in Example 1, except that the oxygen barrier layer coating solution was prepared by adding water to 100 parts by mass (solid content) of polyurethane dispersion (Takelac WPB-341, manufactured by Mitsui Chemicals, Inc., solid content concentration 30%) so that the solid content concentration was 25% by mass, and stirring the mixture. The measurement results are shown in Table 3.

[0089] [Table 1]

[0090] [Table 2]

[0091] [Table 3]

[0092] As can be seen from Tables 1 and 2, the present invention provides a gas barrier laminate that is excellent in oxygen barrier property and water vapor barrier property, as well as in disintegration property.

Claims

1. A gas barrier laminate comprising a paper substrate and an oxygen barrier layer and a water vapor barrier layer in this order on at least one surface of the paper substrate, the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less, the water-soluble resin contains at least one resin selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more; the content of the inorganic compound is 150 parts by mass or more and 540 parts by mass or less relative to 100 parts by mass of the water-soluble resin, the water vapor barrier layer contains a water-dispersible resin, the water-soluble resin contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more but less than 700, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more but less than 2500, Gas barrier laminate.

2. A gas barrier laminate comprising a paper substrate and an oxygen barrier layer and a water vapor barrier layer, in this order, on at least one surface of the paper substrate, the oxygen barrier layer contains a water-soluble resin and an inorganic compound having an aspect ratio of 50 or less and an average particle size of 3 μm or less, the water-soluble resin contains at least one resin selected from the group consisting of polyvinyl alcohol and modified polyvinyl alcohol, each having a saponification degree of 93% or more; the content of the inorganic compound is 150 parts by mass or more and 540 parts by mass or less relative to 100 parts by mass of the water-soluble resin, the water vapor barrier layer contains a water-dispersible resin, the water-soluble resin contains polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more and 500 or less, and polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more and 1200 or less; Gas barrier laminate.

3. 2. The gas barrier laminate according to claim 1, wherein the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 100 or more and less than 700 to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 700 or more and 2500 or less, in the water-soluble resin, is 5:95 to 60:

40.

4. 3. The gas barrier laminate according to claim 2, wherein the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 300 or more and 500 or less to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity-average degree of polymerization of 900 or more and 1200 or less, in the water-soluble resin, is 5:95 to 60:

40.

5. 5. The gas barrier laminate according to claim 1, wherein the oxygen barrier layer further contains a layered inorganic compound having an aspect ratio of 80 or more, and the content of the layered inorganic compound is 25 parts by mass or less per 100 parts by mass of the water-soluble resin.

6. The gas barrier laminate according to any one of claims 1 to 4, wherein the inorganic compound contains kaolin.

7. 5. The gas barrier laminate according to claim 1, wherein the water-dispersible resin contains a styrene / acrylic copolymer.

8. The gas barrier laminate according to any one of claims 1 to 4, wherein the water vapor barrier layer further contains a wax.

9. The gas barrier laminate according to claim 8 , wherein the wax comprises paraffin wax.

10. The amount of the oxygen barrier layer applied is 1 g / m ２ 15g / m or more ２ The gas barrier laminate according to any one of claims 1 to 4, wherein:

11. The amount of the water vapor barrier layer applied is 4 g / m ２ 8g / m or more ２ The gas barrier laminate according to any one of claims 1 to 4, wherein:

12. Water vapor permeability is 20 g / (m ２ 5. The gas barrier laminate according to claim 1, wherein the average temperature is 100°C or less.

13. Oxygen permeability is 30 mL / (m ２ 5. The gas barrier laminate according to claim 1, wherein the gas barrier density is 1000 kJ / s or less.

14. The gas barrier laminate according to any one of claims 1 to 4, which is used as a packaging material.

15. A packaging bag made using the gas barrier laminate according to any one of claims 1 to 4.

16. A method for producing the gas barrier laminate according to any one of claims 1 to 4, comprising the steps of: The method includes a step of laminating an oxygen barrier layer and a water vapor barrier layer on at least one surface of the paper substrate, a water-soluble resin containing a polyvinyl alcohol or a modified polyvinyl alcohol having a viscosity of 2 mPa·s or more and 6 mPa·s or less in a 4% aqueous solution at 20°C, and a polyvinyl alcohol or a modified polyvinyl alcohol having a viscosity of 11 mPa·s or more and 35 mPa·s or less in a 4% aqueous solution at 20°C.

17. 17. The method for producing a gas barrier laminate according to claim 16, wherein the ratio of the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 2 mPa s or more and 6 mPa s or less in a 4% aqueous solution at 20°C to the content of polyvinyl alcohol or modified polyvinyl alcohol having a viscosity of 11 mPa s or more and 35 mPa s or less in a 4% aqueous solution at 20°C is 5:95 to 60:40.

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