Gas barrier layer-forming composition, gas barrier film using the same, packaging film and packaging bag, and method for producing gas barrier film, method for producing packaging film, and method for producing packaging bag

Abstract

A gas barrier layer-forming composition contains a solid component containing a polyurethane resin (A), a water-soluble polymer (B), and a curing agent (C). The polyurethane resin (A) contains a reaction product of an acid group-containing polyurethane resin containing an acid group and a polyamine compound having an amino group. The content of the polyurethane resin (A) in the solid component is 45 mass% or more and 75 mass% or less, the content of the water-soluble polymer (B) in the solid component is 20 mass% or more and 35 mass% or less, and the content of an inorganic layered mineral (D) in the solid component is less than 2 mass%.

Description

Technical Field

[0001] The present disclosure relates to a gas barrier layer-forming composition, a gas barrier film, a packaging film, and a packaging bag using the gas barrier layer-forming composition, and a method for producing the gas barrier film, the packaging film, and the packaging bag. Background Art

[0002] Packaging bags used for food, medicine, and other products require gas barrier properties to prevent the entry of water vapor, oxygen, and other gases that could cause the contents to deteriorate in order to prevent spoilage and maintain their functionality and properties. Therefore, gas barrier films have traditionally been used in these packaging bags.

[0003] The gas barrier film generally includes a gas barrier layer on one side of a resin substrate. The gas barrier layer is formed by applying a gas barrier layer-forming composition capable of imparting gas barrier properties to one side of the resin substrate and curing the composition.

[0004] As such gas barrier films, various films have been developed conventionally.

[0005] For example, Patent Document 1 below discloses a gas barrier film in which a gas barrier layer is formed using a composition containing a solid component composed of a polyurethane resin, a water-soluble polymer, an inorganic layered mineral, and a silane coupling agent as a gas barrier layer-forming composition.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2017-222151 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] However, the gas barrier film described in Patent Document 1 has the following problems.

[0011] In other words, the gas barrier film described in Patent Document 1 has room for improvement in simultaneously satisfying the requirements of abuse resistance, lamination strength after retorting, and bloom suppression. It should be noted that "abuse resistance" refers to the ability to suppress a decrease in at least one of oxygen barrier properties and water vapor barrier properties even when subjected to the Gelboflex test (a test in which a gas barrier film is repeatedly compressed while being twisted).

[0012] The present disclosure has been made in view of the above circumstances, and its object is to provide a composition for forming a gas barrier layer that can impart excellent abuse resistance to a gas barrier film through curing, and can impart high lamination strength even after retorting, while suppressing bleed-out; a gas barrier film, a packaging film, and a packaging bag using the gas barrier layer-forming composition; and a method for producing the gas barrier film, a method for producing the packaging film, and a method for producing the packaging bag.

[0013] Means for solving problems

[0014] The present inventors have conducted extensive research to address the above-mentioned issues and have discovered that, by reducing the content of an inorganic layered mineral, which is included to impart oxygen and water vapor barrier properties, in a gas-barrier layer-forming composition comprising a polyurethane resin, a water-soluble polymer, and a curing agent such as a silane coupling agent, the composition can impart abuse resistance to the gas-barrier film upon curing, achieve high lamination strength even after retorting, and suppress bleed-out. Therefore, the present inventors have conducted further in-depth research, taking into account the respective content ratios of the polyurethane resin and the water-soluble polymer. As a result, they have discovered that the above-mentioned issues can be addressed by the following invention.

[0015] That is, the gas barrier layer-forming composition of the present disclosure comprises a solid component containing a polyurethane resin (A), a water-soluble polymer (B), and a curing agent (C), wherein the polyurethane resin (A) comprises a reaction product of an acid group-containing polyurethane resin containing an acid group and a polyamine compound having an amino group, the content of the polyurethane resin (A) in the solid component is 45% by mass to 75% by mass, the content of the water-soluble polymer (B) in the solid component is 20% by mass to 35% by mass, and the content of the inorganic layered mineral (D) in the solid component is less than 2% by mass.

[0016] The gas barrier layer-forming composition disclosed herein can impart excellent abuse resistance to a gas barrier film having a gas barrier layer formed from a cured product of the composition on one side of a resin substrate upon curing, and can also impart high lamination strength even after retorting, while suppressing bleed-out.

[0017] The present inventors speculate as follows about the reason why the above-mentioned effects are obtained by the composition for forming a gas barrier layer disclosed herein.

[0018] That is, it is believed that when the gas barrier layer-forming composition is cured, the curing agent in the gas barrier layer-forming composition can be bonded to the layer adjacent to the gas barrier layer, and can form a network by a curing reaction with the polyurethane resin or water-soluble polymer in the gas barrier layer-forming composition. In addition, by reducing the content of the inorganic layered mineral in the solid component, when the gas barrier layer-forming composition is cured, the curing agent is more likely to be bonded to the layer adjacent to the gas barrier layer, and further promotes the curing reaction with the polyurethane resin or water-soluble polymer in the gas barrier layer-forming composition, thereby making it easier to form a network. Therefore, the gas barrier layer is fully fitted to the layer adjacent to it and has excellent abuse resistance. In addition, by preventing the content of the curing agent from becoming too large, the curing agent can be kept in the composition. As a result, the present inventors speculate that the above-mentioned effect can be obtained by the gas barrier layer-forming composition disclosed herein.

[0019] In the above-mentioned gas barrier layer-forming composition, it is preferred that the content of the inorganic layered mineral (D) in the solid component is 0% by mass, and the total content of the polyurethane resin (A), the water-soluble polymer (B) and the curing agent (C) in the solid component is 100% by mass.

[0020] In this case, the gas barrier layer-forming composition can impart greater lamination strength to the gas barrier film even after the retort treatment by curing.

[0021] In the gas barrier layer-forming composition, the content of the curing agent (C) in the solid component is preferably 20% by mass or less.

[0022] In this case, compared with the case where the content of the curing agent (C) in the solid component exceeds 20% by mass, the curing agent (C) is less likely to bleed out, thereby suppressing surface contamination.

[0023] In the gas barrier layer-forming composition, the content of the curing agent (C) in the solid component is preferably 5% by mass or more.

[0024] In this case, compared with a case where the content of the curing agent (C) in the solid content is less than 5% by mass, curing can impart greater lamination strength to the gas barrier film even after retorting.

[0025] In the gas barrier layer-forming composition, the water-soluble polymer (B) is preferably polyvinyl alcohol or a modified form thereof.

[0026] The composition, when cured, can impart even better gas barrier properties to the gas barrier film. Furthermore, the composition, when cured, can impart even better flexibility and even better abuse resistance to the gas barrier film.

[0027] In the gas barrier layer-forming composition, the water-soluble polymer (B) preferably does not have a silanol group.

[0028] In this case, the gas barrier properties of the gas barrier layer can be further improved compared to the case where the water-soluble polymer (B) has a silanol group.

[0029] In the gas barrier layer-forming composition, the curing agent (C) preferably has an epoxy group.

[0030] In this case, the composition can have more excellent hot water resistance by curing, and can impart greater lamination strength to the gas barrier film even after retorting.

[0031] The gas barrier film of the present disclosure includes a resin substrate and a gas barrier layer provided on one surface of the resin substrate and composed of a cured product of the gas barrier layer-forming composition.

[0032] In this gas barrier film, the gas barrier layer provided on one surface of the resin substrate is composed of a cured product of a gas barrier layer-forming composition. Curing of the gas barrier layer-forming composition imparts excellent abuse resistance to the gas barrier film, provides high lamination strength even after retorting, and suppresses bleed-out. Therefore, the gas barrier film disclosed herein exhibits excellent abuse resistance, high lamination strength even after retorting, and suppresses bleed-out.

[0033] In the gas barrier film, the gas barrier layer preferably has a thickness of 800 nm or less.

[0034] In this case, compared with a case where the thickness of the gas barrier layer exceeds 800 nm, the flexibility of the gas barrier film can be further improved, and the abuse resistance of the gas barrier film can be further improved.

[0035] In the gas barrier film, the gas barrier layer preferably has a thickness of 150 nm or more.

[0036] In this case, the gas barrier properties of the gas barrier film can be further improved compared to a case where the thickness of the gas barrier layer is less than 150 nm.

[0037] Preferably, the gas barrier film further comprises an inorganic oxide layer containing an inorganic oxide between the resin substrate and the gas barrier layer, wherein the inorganic oxide includes an inorganic oxide composed of silicon oxide.

[0038] This gas barrier film can have more excellent water vapor barrier properties.

[0039] In the gas barrier film, the inorganic oxide preferably includes an inorganic oxide composed of silicon oxide.

[0040] This gas barrier film can have more excellent water vapor barrier properties.

[0041] Furthermore, the packaging film of the present disclosure includes the above-mentioned gas barrier film and a sealant layer laminated on the gas barrier film.

[0042] This packaging film has excellent abuse resistance, maintains high lamination strength even after retorting, and suppresses oozing. Therefore, the packaging film having the gas barrier film also has excellent abuse resistance, maintains high lamination strength even after retorting, and suppresses oozing. Furthermore, since the packaging film includes a sealant layer, bonding the sealants together allows for easy production of a hermetically sealed packaging bag.

[0043] Furthermore, the packaging bag of the present disclosure is formed by using the above-mentioned packaging film and bonding the sealing layers to each other.

[0044] This packaging bag is formed by bonding sealing layers together using a packaging film having a gas barrier film that exhibits excellent abuse resistance, maintains high lamination strength even after retorting, and prevents leakage. Therefore, the packaging bag disclosed herein exhibits excellent abuse resistance, inhibits delamination (interlayer separation), and prevents leakage even after retorting. Furthermore, since the packaging bag is formed using a packaging film having a sealing layer, it can ensure sufficient sealing.

[0045] In addition, the method for manufacturing a gas barrier film disclosed herein is a method for manufacturing a gas barrier film comprising a resin substrate and a gas barrier layer provided on one side of the resin substrate, comprising: curing the above-mentioned gas barrier layer-forming composition on one side of the resin substrate to form the gas barrier layer, thereby manufacturing the gas barrier film.

[0046] According to this production method, in the gas barrier layer formation step, the gas barrier layer-forming composition is cured on one side of a resin substrate to form a gas barrier layer, thereby producing a gas barrier film. In this case, the gas barrier layer-forming composition used in the gas barrier layer formation step, upon curing, can impart excellent abuse resistance to the gas barrier film having a gas barrier layer composed of a cured product of the composition on one side of the resin substrate, and can also impart high lamination strength even after retorting, while also suppressing bleed-out. Therefore, according to the production method disclosed herein, it is possible to produce a gas barrier film having excellent abuse resistance, high lamination strength even after retorting, and suppressed bleed-out.

[0047] The packaging film production method of the present disclosure includes: a gas barrier film production step of producing a gas barrier film by the above-mentioned gas barrier film production method; and a sealant layer laminating step of laminating a sealant layer on the gas barrier film to obtain a packaging film.

[0048] This manufacturing method enables the production of a gas barrier film during the gas barrier film production process that exhibits excellent abuse resistance, high lamination strength even after retorting, and reduced oozing. Therefore, in the sealant layer lamination process, by laminating the sealant layer so that it is positioned on one side of the resin substrate of the gas barrier film, a packaging film can be produced that exhibits excellent abuse resistance, high lamination strength even after retorting, and reduced oozing. Furthermore, since the produced packaging film includes the sealant layer, bonding the sealant layers together facilitates the production of a securely sealed packaging bag.

[0049] Furthermore, the method for manufacturing a packaging bag of the present disclosure includes: a packaging film manufacturing step of manufacturing a packaging film by the above-mentioned packaging film manufacturing method; and a packaging film bonding step of manufacturing a packaging bag by using the packaging film and bonding the sealing layers to each other.

[0050] This manufacturing method allows for the production of packaging films that exhibit excellent abuse resistance, high lamination strength even after retorting, and reduced oozing during the packaging film production process. Consequently, during the packaging film bonding process, when the packaging films are used and the sealing layers are bonded to each other, a packaging bag can be produced that exhibits excellent abuse resistance, reduces delamination, and reduces oozing even after retorting. Furthermore, the disclosed manufacturing method ensures sufficient sealing properties for the packaging bags produced by using packaging films having sealing layers.

[0051] Effects of the Invention

[0052] According to the present disclosure, there can be provided a composition for forming a gas barrier layer that can impart excellent abuse resistance to a gas barrier film by curing, impart high lamination strength even after retorting, and suppress bleed-out; a gas barrier film, a packaging film, and a packaging bag using the gas barrier layer-forming composition; and a method for producing a gas barrier film, a method for producing a packaging film, and a method for producing a packaging bag. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] [ Figure 1 ] is a cross-sectional view showing one embodiment of the gas barrier film disclosed herein.

[0054] [ Figure 2 ] is a cross-sectional view showing an embodiment of the packaging film of the present invention.

[0055] [ Figure 3 ] is a side view showing an embodiment of the packaging bag of the present invention.

[0056] [ Figure 4 ] is a perspective view showing an example of a packaging bag with a spout (gusseted bag with a nozzle) to which the packaging bag disclosed herein is applied.

[0057] [ Figure 5 ] is a front view showing an example of a tube container to which the packaging film of the present disclosure is applied. DETAILED DESCRIPTION

[0058] Hereinafter, embodiments of the present disclosure will be described in detail.

[0059] <Gas Barrier Layer-Forming Composition>

[0060] The gas barrier layer-forming composition comprises a solid component containing a polyurethane resin (A), a water-soluble polymer (B), and a curing agent (C). The polyurethane resin (A) comprises a reaction product of an acid-group-containing polyurethane resin and a polyamine compound having an amino group. Furthermore, the content of the polyurethane resin (A) in the solid component is 45% to 75% by mass, the content of the water-soluble polymer (B) in the solid component is 20% to 35% by mass, and the content of the inorganic layered mineral (D) in the solid component is less than 2% by mass.

[0061] The gas barrier layer-forming composition disclosed herein can impart excellent abuse resistance to a gas barrier film having a gas barrier layer formed from a cured product of the composition on one side of a resin substrate through curing, and can also impart high lamination strength even after retorting, while suppressing bleed-out.

[0062] Hereinafter, the gas barrier layer-forming composition will be described in detail.

[0063] (A) Polyurethane resin

[0064] The polyurethane resin comprises a reaction product of an acid-group-containing polyurethane resin and a polyamine compound having amino groups. In other words, the reaction product is a combination of the acid-group-containing polyurethane resin and the polyamine compound, and is composed of a bond formed through bonds between the acid groups of the acid-containing polyurethane resin and the amino groups of the polyamine compound.

[0065] The acid group of the acid group-containing polyurethane resin may be any one that can bond to the amino group of the polyamine compound constituting the polyurethane resin (A), and examples of the acid group include a carboxyl group and a sulfonic acid group.

[0066] As the acid group-containing polyurethane resin, for example, a resin having a structural unit containing a cyclic hydrocarbon and a structural unit containing a chain hydrocarbon is used.

[0067] Specific examples of the acid group-containing polyurethane resin include carboxylic acid-modified polyurethane resins and sulfonic acid-modified polyurethane resins, etc. These can be used alone or in combination of two or more.

[0068] The amino group of the polyamine compound may be any of a primary amino group, a secondary amino group, and a tertiary amino group.

[0069] Specific examples of the polyamine compound include alkylenediamines and polyalkylenepolyamines, etc. These can be used alone or in combination of two or more.

[0070] The bond between the acid group of the acid group-containing polyurethane resin and the amino group of the polyamine compound may be an ionic bond (eg, an ionic bond between a carboxyl group and a tertiary amino group) or a covalent bond (eg, an amide bond).

[0071] The number average molecular weight of the polyurethane resin (A) is not particularly limited, but is preferably 800 to 1,000,000. In this case, the viscosity of the gas barrier layer-forming composition can be further reduced compared to when the number average molecular weight of the polyurethane resin (A) exceeds 1,000,000, thereby facilitating the application of the gas barrier layer-forming composition. In addition, compared to when the number average molecular weight of the polyurethane resin (A) is less than 800, it is possible to impart better gas barrier properties to the gas barrier film. Here, the number average molecular weight of the polyurethane resin (A) is a value calculated in terms of standard polystyrene as measured by gel permeation chromatography (GPC).

[0072] The number average molecular weight of the polyurethane resin (A) is more preferably 800 to 200,000, further preferably 800 to 100,000.

[0073] The polyurethane resin (A) content in the solids component is 45% to 75% by mass. In this case, curing can impart greater lamination strength to the gas barrier film even after retorting, compared to a case where the polyurethane resin (A) content in the solids component is less than 45% by mass. On the other hand, curing can impart superior abuse resistance to the gas barrier film, compared to a case where the polyurethane resin (A) content in the solids component exceeds 75% by mass.

[0074] The content of the polyurethane resin (A) in the solid content is preferably 47% by mass or more, more preferably 50% by mass or more, particularly preferably 60% by mass or more.

[0075] The content of the polyurethane resin (A) in the solid content is preferably 74% by mass or less, more preferably 72% by mass or less, particularly preferably 65% ​​by mass or less.

[0076] (B) Water-soluble polymers

[0077] The water-soluble polymer (B) refers to a polymer that can dissolve in water.

[0078] Specific examples of water-soluble polymers (B) include polyvinyl alcohol resins, modified forms thereof, and polyacrylic acid. These can be used alone or in combination of two or more. Among them, polyvinyl alcohol resins or modified forms thereof are preferred as water-soluble polymers (B). In this case, the composition can impart better gas barrier properties to the gas barrier film by curing. In addition, even if the composition is cured, it can impart better flexibility to the gas barrier film, thereby imparting better abuse resistance.

[0079] Polyvinyl alcohol resin is composed of a homopolymer of vinyl alcohol or a vinyl alcohol-vinyl acetate copolymer. Modified polyvinyl alcohol resins are obtained by further introducing structural units derived from monomers other than vinyl alcohol or vinyl acetate into polyvinyl alcohol resin. Examples of such monomers include monomers having silanol groups and monomers having carboxyl groups.

[0080] The water-soluble polymer (B) is preferably a polyvinyl alcohol resin. In this case, the gas barrier properties of the gas barrier layer can be further improved compared to a case where the water-soluble polymer (B) is a modified form of the polyvinyl alcohol resin.

[0081] The water-soluble polymer (B) may or may not have a silanol group, but preferably does not have a silanol group.

[0082] In this case, the gas barrier properties of the gas barrier layer can be further improved compared to the case where the water-soluble polymer (B) has a silanol group.

[0083] When the water-soluble polymer (B) is composed of a polyvinyl alcohol resin or a modified form thereof, the saponification degree of the water-soluble polymer (B) is not particularly limited, but is preferably 95% or more, and may be 100%, from the viewpoint of improving the gas barrier properties of the gas barrier film 10 .

[0084] The degree of polymerization of the water-soluble polymer (B) is not particularly limited, but is preferably 300 or higher, more preferably 450 or higher, from the viewpoint of improving the gas barrier properties of the gas barrier film 10. The degree of polymerization of the water-soluble polymer (B) is preferably 2400 or lower.

[0085] The content of the water-soluble polymer (B) in the solid component is 20% to 35% by mass. In this case, curing can impart superior abuse resistance to the gas barrier film compared to a case where the content of the water-soluble polymer (B) in the solid component is less than 20% by mass. On the other hand, curing can impart greater lamination strength to the gas barrier film even after retorting compared to a case where the content of the water-soluble polymer (B) in the solid component exceeds 35% by mass.

[0086] The content of the water-soluble polymer (B) in the solid component is preferably 20% by mass or more, more preferably 21% by mass or more, and particularly preferably 25% by mass or more.

[0087] The content of the water-soluble polymer (B) in the solid component is preferably 34% by mass or less, more preferably 33% by mass or less, and particularly preferably 32% by mass or less.

[0088] (C) Curing agent

[0089] The curing agent (C) is not limited as long as it can cure the gas barrier layer-forming composition. However, from the viewpoint of imparting greater lamination strength to the gas barrier film even after retort treatment by curing, a silane coupling agent is particularly preferably used as the curing agent (C).

[0090] Examples of the silane coupling agent include compounds represented by the following general formula (1).

[0091] Si(OR 1 ) p (R 2 ) 3-p R 3 …(1)

[0092] In the above general formula (1), R 1 represents an alkyl group such as methyl or ethyl, R 2 represents a monovalent organic group such as an alkyl group substituted with an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an acryloyloxy group, or a methacryloyloxy group, and R 3 represents a monovalent organic functional group, and p represents an integer of 1 to 3. 1 or R 2 In the case of R 1 Each other or R 2 They can be the same or different. 3Examples of the monovalent organic functional group represented by include those containing a vinyl group, an epoxy group, a mercapto group, an amino group, or an isocyanate group. Among these, the monovalent organic functional group is preferably a functional group containing an epoxy group. In this case, the composition can exhibit superior hot water resistance upon curing, and can impart greater lamination strength to the gas barrier film even after retorting.

[0093] Examples of the silane coupling agent include vinyl-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane; epoxy-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 3-glycidoxypropylethyldiethoxysilane; mercapto-containing silane coupling agents such as 3-mercaptopropyltrimethoxysilane and 3-mercaptopropylmethyldimethoxysilane; amino-containing silane coupling agents such as 3-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and isocyanate-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane. These silane coupling agents may be used alone or in combination of two or more.

[0094] The content of the curing agent (C) in the solid content is not particularly limited as long as it is greater than 0% by mass.

[0095] The content of the curing agent (C) in the solid component is preferably 5% by mass or more, more preferably 7% by mass or more, and particularly preferably 8% by mass or more. In this case, compared with a case where the content of the curing agent (C) in the solid component is less than 5% by mass, curing can impart greater lamination strength to the gas barrier film even after retorting.

[0096] The content of the curing agent (C) in the solid component is preferably 20% by mass or less, more preferably 15% by mass or less, and particularly preferably 13% by mass or less. In this case, the curing agent (C) is less likely to ooze out than when the content of the curing agent (C) in the solid component exceeds 20% by mass, thereby suppressing surface contamination.

[0097] (D) Inorganic layered minerals

[0098] The inorganic layered mineral (D) refers to an inorganic compound in which unit crystal layers are stacked to form a single layered particle.

[0099] Examples of the inorganic layered mineral (D) include hydrous silicates such as phyllosilicate minerals. Specific examples of the hydrous silicates include kaolinite clay minerals such as halloysite, kaolinite, and halloysite; serpentine clay minerals such as antigorite and chrysotile; smectite clay minerals such as montmorillonite and beidellite; vermiculite clay minerals such as vermiculite; and micas such as synthetic mica, muscovite, and phlogopite. These can be used alone or in combination of two or more.

[0100] The content of the inorganic layered mineral (D) in the solid component is less than 2% by mass. In this case, a greater lamination strength can be imparted to the gas barrier film by curing compared to a case where the content of the inorganic layered mineral (D) in the solid component is 2% by mass or more.

[0101] The content of the inorganic layered mineral (D) in the solid component is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.1% by mass or less. The content of the inorganic layered mineral (D) in the solid component may be 0% by mass.

[0102] (Other ingredients in the solid content)

[0103] The solid content may contain known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity modifier, and a colorant as needed, within a range that does not impair the gas barrier properties of the gas barrier layer.

[0104] (Total content of components in solid content)

[0105] The total content of the polyurethane resin (A), water-soluble polymer (B), curing agent (C) and inorganic layered mineral (D) in the solid component is not particularly limited, but is usually 95% by mass or more, preferably 97% by mass or more, and may be 100% by mass.

[0106] When the content of the inorganic layered mineral (D) in the solid component is 0 mass %, the total content of the polyurethane resin (A), the water-soluble polymer (B) and the curing agent (C) in the solid component is preferably 100 mass %.

[0107] In this case, the gas barrier layer-forming composition can impart greater lamination strength to the gas barrier film upon curing.

[0108] (liquid)

[0109] An aqueous medium is typically used as the liquid for dissolving or dispersing the solid component. Examples of the aqueous medium include water, hydrophilic organic solvents, or mixtures thereof. Examples of hydrophilic organic solvents include alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosolves; carbitols; and nitriles such as acetonitrile. These can be used alone or in combination of two or more.

[0110] The aqueous medium is preferably an aqueous medium consisting solely of water or an aqueous medium containing water as a main component. When the aqueous medium contains water as a main component, the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more.

[0111] Gas barrier film

[0112] Figure 1 : is a cross-sectional view showing one embodiment of the gas barrier film disclosed herein. Figure 1 In the embodiment, the gas barrier film 10 includes a resin substrate 1 and a gas barrier layer 4 provided on one surface of the resin substrate 1. Between the resin substrate 1 and the gas barrier layer 4, an underlayer 2 and an inorganic oxide layer 3 are provided in this order from the resin substrate 1 side. The gas barrier layer 4 is composed of a cured product of the gas barrier layer-forming composition described above.

[0113] In this gas barrier film 10, the gas barrier layer 4 provided on one surface of the resin substrate 1 is composed of a cured product of a gas barrier layer-forming composition. Curing of the gas barrier layer-forming composition imparts excellent abuse resistance to the gas barrier film 10, provides high lamination strength even after retorting, and suppresses bleed-out. Consequently, the gas barrier film 10 exhibits excellent abuse resistance, high lamination strength even after retorting, and suppresses bleed-out.

[0114] Hereinafter, the resin substrate 1 , the underlayer 2 , the inorganic oxide layer 3 , and the gas barrier layer 4 will be described in detail.

[0115] (Resin base material)

[0116] The resin substrate 1 is a substrate that serves as a support for the gas barrier layer 4 and comprises a resin. Examples of the resin include polyolefin resins, polyester resins, polyamide resins, polyether resins, acrylic resins, polyimide resins, epoxy resins, and natural polymer compounds (such as cellulose acetate). These resins may be used alone or as a mixture of two or more.

[0117] Among these, polyolefin resins are preferably used from the perspective of recycling. Examples of polyolefin resins include polyethylene and polypropylene, but polypropylene is preferred from the perspective of retort resistance. Polypropylene may be either homopolypropylene or a propylene copolymer, but from the perspective of oxygen barrier properties, the polypropylene constituting at least the surface layer of the resin substrate 1 on the gas barrier layer 4 side is more preferably a polypropylene copolymer.

[0118] The resin substrate 1 may be a stretched film or an unstretched film, but a stretched film is preferred from the viewpoint of oxygen barrier properties. Here, as the stretched film, uniaxially stretched film and biaxially stretched film can be cited, but biaxially stretched film is preferred because it improves heat resistance.

[0119] The thickness of the resin base material 1 is not particularly limited, and may be, for example, 10 μm or more and 0.1 mm or less.

[0120] The resin base material 1 may contain additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, and a lubricant as needed.

[0121] (basal layer)

[0122] The underlayer 2 is a layer for further improving the adhesion between the resin base material 1 and the inorganic oxide layer 3 , and is sandwiched between the resin base material 1 and the inorganic oxide layer 3 .

[0123] The material constituting the base layer 2 is not particularly limited as long as it can improve the adhesion between the resin substrate 1 and the inorganic oxide layer 3. Such materials include reaction products of organosilanes or organometallic compounds, polyol compounds, and isocyanate compounds. That is, the base layer 2 can also be called a urethane adhesive layer. Organosilanes are, for example, trifunctional organosilanes or hydrolyzates of trifunctional organosilanes. Organometallic compounds are, for example, metal alkoxides or hydrolyzates of metal alkoxides. Metal elements contained in organometallic compounds are, for example, Al, Ti, Zr, etc. The hydrolyzates of organosilanes and metal alkoxides only need to have at least one hydroxyl group. From the perspective of transparency, the polyol compound is preferably an acrylic polyol. The isocyanate compound mainly functions as a crosslinking agent or a curing agent. The polyol compound and the isocyanate compound can be monomers or polymers.

[0124] The thickness of the base layer 2 is not particularly limited as long as it can improve the adhesion between the resin substrate 1 and the inorganic oxide layer 3, but is preferably 30 nm or more. In this case, compared with the case where the thickness of the base layer 2 is less than 30 nm, it is easy to obtain good adhesion between the resin substrate 1 and the inorganic oxide layer 3. In addition, the durability of the base layer 2 is further improved. The thickness of the base layer 2 is preferably 30 nm or more, more preferably 35 nm or more, and further preferably 40 nm or more. By increasing the thickness of the base layer 2, the reduction in water vapor barrier properties when external forces such as stretching are applied can be further suppressed. The thickness of the base layer 2 is preferably less than 200 nm. In this case, compared with the case where the thickness of the base layer 2 is 200 nm or more, the base layer 2 tends to be less likely to crack.

[0125] (Inorganic oxide layer)

[0126] The inorganic oxide layer 3 is a layer containing an inorganic oxide. The gas barrier film 10 can have more excellent water vapor barrier properties by including the inorganic oxide layer 3.

[0127] Examples of inorganic oxides include silicon oxide (SiO x ), and metal oxides. As the metal constituting the metal oxide, at least one atom selected from the group consisting of Al, Mg, Sn, Ti and In can be cited. As the inorganic oxide, SiO is preferred from the viewpoint of water vapor barrier properties. x or AlO x Among them, SiO is preferred x In this case, the gas barrier film 10 can have more excellent water vapor barrier properties.

[0128] The inorganic oxide layer 3 may be composed of a single layer or a plurality of layers.

[0129] The thickness of the inorganic oxide layer 3 is not particularly limited, but is preferably 10 nm to 100 nm. In this case, the water vapor barrier properties of the gas barrier film 10 are likely to be improved compared to when the thickness of the inorganic oxide layer 3 is less than 10 nm. In addition, compared to when the thickness of the inorganic oxide layer 3 exceeds 100 nm, cracks are less likely to form due to increased internal stress, thereby further suppressing a decrease in water vapor barrier properties.

[0130] The thickness of the inorganic oxide layer 3 is more preferably not less than 10 nm and not more than 100 nm.

[0131] (Gas barrier layer)

[0132] The gas barrier layer 4 is composed of a cured product of the above-mentioned gas barrier layer-forming composition.

[0133] The thickness of the gas barrier layer 4 is not particularly limited, but is preferably 800 nm or less.

[0134] In this case, compared with a case where the thickness of the gas barrier layer 4 exceeds 800 nm, the flexibility of the gas barrier layer 4 can be further improved, and the abuse resistance of the gas barrier layer 4 can be further improved.

[0135] From the viewpoint of improving gas barrier properties, the thickness of the gas barrier layer 4 is more preferably 150 nm or more, particularly preferably 180 nm or more. In this case, the gas barrier properties of the gas barrier layer 4 can be further improved compared to a case where the thickness of the gas barrier layer 4 is less than 150 nm.

[0136] From the viewpoint of improving abuse resistance, the thickness of the gas barrier layer 4 is more preferably 750 nm or less, particularly preferably 500 nm or less.

[0137] <Method for producing gas barrier film>

[0138] Next, a method for producing the gas barrier film 10 will be described.

[0139] First, the resin base material 1 is prepared.

[0140] Next, the base layer 2 is formed on one surface of the resin base material 1 .

[0141] Specifically, the base layer 2 can be formed by applying a composition containing, for example, an organosilane or organometallic compound, a polyol compound, and an isocyanate compound onto one surface of the resin substrate 1 and then heating and drying it. The heating temperature is, for example, 50 to 200° C., and the drying time is, for example, about 10 seconds to 10 minutes.

[0142] Next, the inorganic oxide layer 3 is formed on the base layer 2 .

[0143] The inorganic oxide layer 3 can be formed, for example, by a vacuum film-forming method. Examples of vacuum film-forming methods include physical vapor deposition and chemical vapor deposition. Examples of physical vapor deposition include vacuum evaporation, sputtering, and ion plating. As a physical vapor deposition method, vacuum evaporation is particularly preferred. Examples of vacuum evaporation include resistance heating vacuum evaporation, EB (Electron Beam) heating vacuum evaporation, and induction heating vacuum evaporation. Examples of chemical vapor deposition include thermal CVD, plasma CVD, and optical CVD.

[0144] Next, the gas barrier layer 4 is formed on the inorganic oxide layer 3 (gas barrier layer forming step).

[0145] The gas barrier layer 4 can be formed, for example, by applying a gas barrier layer-forming composition to the surface of the inorganic oxide layer 3 opposite to the base layer 2 and curing the composition. Here, curing the solid component means that the polyurethane resin (A), the water-soluble polymer (B), and the curing agent (C) in the solid component react with each other and become integrated.

[0146] The gas barrier layer-forming composition can be applied by a known method, specifically, wet film-forming methods such as gravure coating, dip coating, reverse coating, wire bar coating, and die coating.

[0147] Curing can be performed by heating, for example.

[0148] When curing is performed by heating, the heating temperature and heating time can be set so as to simultaneously cure the solid components in the gas barrier layer-forming composition and remove the liquid such as the aqueous medium. The heating temperature can be, for example, 80 to 250°C, and the heating time can be, for example, 3 seconds to 10 minutes.

[0149] In the above manner, the production of the gas barrier film 10 is completed.

[0150] According to this production method, in the gas barrier layer formation step, the gas barrier layer 4 is formed by curing the aforementioned gas barrier layer-forming composition on one side of the resin substrate 1, thereby producing a gas barrier film 10. In this case, the gas barrier layer-forming composition used in the gas barrier layer formation step, upon curing, can impart excellent abuse resistance to the gas barrier film 10 having the gas barrier layer 4 formed of a cured product of the composition on one side of the resin substrate 1, while also providing high lamination strength even after retorting and suppressing bleed-out. Therefore, according to the production method disclosed herein, it is possible to produce a gas barrier film 10 that exhibits excellent abuse resistance, high lamination strength even after retorting, and suppresses bleed-out.

[0151] <Packaging film>

[0152] Next, refer to Figure 2 The embodiment of the packaging film disclosed in the present invention is described. Figure 2 In, with Figure 1 The same components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0153] Figure 2 1 is a cross-sectional view showing an embodiment of the packaging film of the present disclosure. Figure 2 As shown, the packaging film 20 includes a gas barrier film 10 and a sealant layer 21 laminated on the gas barrier film 10. The sealant layer 21 is disposed on one side of the resin substrate 1 of the gas barrier film 10. Figure 2In the embodiment, the gas barrier layer 4 and the sealant layer 21 of the gas barrier film 10 are bonded together via the adhesive layer 22 .

[0154] This packaging film 20 has excellent abuse resistance, maintains high lamination strength even after retorting, and suppresses oozing. Therefore, the packaging film 20 including the gas barrier film 10 also has excellent abuse resistance, maintains high lamination strength even after retorting, and suppresses oozing. Furthermore, since the packaging film 20 includes the sealant layer 21, it is easy to manufacture packaging bags that can be sealed by bonding the sealant layers 21.

[0155] As the material of the adhesive layer 22, polyester-isocyanate resin, urethane resin, polyether resin, etc. can be used. In order to use the packaging film 20 for retort applications, a two-component curing urethane adhesive having retort resistance can be preferably used.

[0156] (Sealing layer)

[0157] The material for sealant layer 21 includes thermoplastic resins such as polyolefin resins and polyester resins, but polyolefin resins are generally used. Specifically, polyolefin resins include ethylene resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), linear low-density polyethylene resin (LLDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-(meth)acrylic acid copolymer; polypropylene resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer; and mixtures thereof. The material for sealant layer 21 can be appropriately selected from the aforementioned thermoplastic resins depending on the intended use and the temperature conditions of boiling, retorting, and other processes.

[0158] The thickness of the sealant layer 21 is appropriately determined depending on the mass of the content, the shape of the packaging bag, etc., and is preferably 30 to 150 μm, more preferably 50 to 100 μm, from the viewpoint of flexibility and adhesiveness of the packaging film 20 .

[0159] <Method for producing packaging film>

[0160] Next, a method for producing the packaging film 20 will be described.

[0161] First, the gas barrier film 10 is produced by the above-mentioned method for producing a gas barrier film (gas barrier film production step).

[0162] Next, the sealant layer 21 is bonded and laminated using the adhesive layer 22 so as to be arranged on one surface side of the resin substrate 1 of the gas barrier film 10 , thereby obtaining the packaging film 20 (sealant layer laminating step).

[0163] According to this production method, a gas barrier film 10 can be produced in the gas barrier film production process, exhibiting excellent abuse resistance, high lamination strength even after retorting, and suppressing bleed-out. Therefore, in the sealant layer lamination process, by laminating the sealant layer 21 so that it is positioned on one side of the resin substrate 1 of the gas barrier film 10, a packaging film 20 can be produced that exhibits excellent abuse resistance, high lamination strength even after retorting, and suppresses bleed-out. Furthermore, since the produced packaging film 20 includes the sealant layer 21, it can be easily used to produce packaging bags that can be sealed by bonding the sealant layers 21 to each other.

[0164] The packaging film 20 has an adhesive layer 22. However, if the sealant layer 21 is made of the aforementioned thermoplastic resin and can be bonded to the gas barrier layer 4 of the gas barrier film 10 by heat fusion, the adhesive layer 22 can be omitted. In this case, the sealant layer 21 is bonded to the resin substrate 1 by, for example, an extrusion lamination method in which the gas barrier film 10 is heated and melted, extruded and bonded in a curtain shape.

[0165] <Packaging Bag>

[0166] Next, refer to Figure 3 The embodiment of the packaging bag disclosed in the present invention is described. Figure 3 In, with Figure 1 or Figure 2 The same components are denoted by the same reference numerals, and redundant descriptions are omitted.

[0167] Figure 3 1 is a side view showing an embodiment of the packaging bag of the present disclosure. Figure 3 As shown, the packaging bag 30 is a packaging bag formed by using the packaging film 20 and bonding the sealing layers 21 to each other.

[0168] This packaging bag 30 is formed by bonding sealing layers 21 to packaging film 20. The packaging film 20 includes a gas barrier film 10 that exhibits excellent abuse resistance, high lamination strength even after retorting, and suppresses oozing. Consequently, the packaging bag 30 exhibits excellent abuse resistance, suppresses delamination (interlayer separation), and suppresses oozing even after retorting. Furthermore, since the packaging bag 30 is formed using packaging film 20 with sealing layers 21, it also ensures sufficient sealing.

[0169] <Method for manufacturing packaging bags>

[0170] Next, a method for manufacturing the packaging bag 30 will be described.

[0171] First, the packaging film 20 is manufactured by the above-mentioned method for manufacturing the packaging film 20 (packaging film manufacturing step).

[0172] Next, the packaging film 20 is used to bond the sealing layers 21 to each other so as to form an opening, thereby obtaining a bonded body. Food, medicine, or other contents are then placed through the opening of the bonded body, and the opening of the bonded body is then sealed, thereby producing a packaging bag 30 (packaging film bonding step).

[0173] According to this manufacturing method, during the packaging film manufacturing process, a packaging film 20 can be produced that exhibits excellent abuse resistance, high lamination strength even after retorting, and reduced oozing. Consequently, in the packaging film bonding process, by using the packaging film 20 and bonding the sealant layers 21 to each other, a packaging bag 30 can be produced that exhibits excellent abuse resistance, reduces delamination even after retorting, and reduces oozing. Furthermore, according to this packaging bag manufacturing method, by using the packaging film 20 having the sealant layer 21 to manufacture the packaging bag 30, sufficient sealing properties can be ensured.

[0174] In the packaging film joining step, the joined body can be formed by: bending one packaging film 20 so that the sealing layers 21 face each other, and then heat-melting the peripheral edges of the facing sealing layers 21; or overlapping two packaging films 20 so that the sealing layers 21 face each other, and then heat-melting the peripheral edges of the facing sealing layers 21.

[0175] It should be noted that, in the packaging film joining step, the contents may not necessarily be accommodated in the joined body. In this case, the joined body with an opening becomes a packaging bag.

[0176] For example, in the above embodiment, the gas barrier film 10 includes the base layer 2 and the inorganic oxide layer 3 , but at least one of the base layer 2 and the inorganic oxide layer 3 may be omitted.

[0177] In addition, in the above embodiment, in the packaging film 20, the sealing layer 21 is arranged on one side of the resin substrate 1 of the gas barrier film 10 (the gas barrier layer 4 side), but the sealing layer 21 can also be arranged on the other side of the resin substrate 1 (the side opposite to the gas barrier layer 4), or can be arranged on one side and the other side of the resin substrate 1.

[0178] Furthermore, the packaging bag disclosed herein can also be used as a packaging bag with a spout. Examples of packaging bags with a spout include: a structure in which the spout is sandwiched and fixed between two sheets of packaging film forming the packaging bag; and a structure in which a spout is opened on one side of the packaging bag and adhesively fixed. The spout can be located on the top of the packaging bag, diagonally above the packaging bag, or on the side or bottom of the packaging bag. If the contents of the packaging bag are liquid or gel-like foods, in addition to the spout spout (so-called nozzle), a straw that reaches the bottom of the packaging bag can be provided to allow direct suction.

[0179] Figure 4 This is a perspective view showing an example of a packaging bag with a spout (a gusseted bag with a spout) to which the packaging bag disclosed herein is applied. Figure 4 The illustrated packaging bag 100 with a spout has a spout 104 that is sandwiched and secured within a sealing portion 130 of a packaging film forming a packaging bag 140. Spout 104 is provided with a straw 105 that reaches the bottom of packaging bag 140. Furthermore, packaging bag 100 with a spout can be sealed by closing a spout cover 104a. The packaging bag 140 constituting the packaging bag 100 with a spout can be a gusseted bag that expands at the bottom when filled with contents, forming a downwardly inflated shape and capable of self-supporting.

[0180] In addition, the packaging film of the present disclosure can also be used as an extrusion bag. A resealable plug can be provided in the extrusion bag, or a discharge port can be provided by tearing the bag as a disposable bag.

[0181] The packaging film disclosed herein can be used as the main body of a bag-in-box (BIB) liner bag, particularly one equipped with a spout (tube) for pouring. A BIB comprises a bag (inner bag) and a carton (outer box) that houses the bag, with the bag containing liquids such as soft drinks or alcoholic beverages.

[0182] In the case of any of the above-mentioned packaging bags with a spout, from the viewpoint of improving recyclability, it is preferred that the spout portion or the entire spout including the lid be made of the same resin as that contained in the resin base material and gas barrier layer of the packaging film.

[0183] The packaging film disclosed herein can also be used as the main body of a tube container. Tube containers generally consist of a main body made of a packaging film and a spout manufactured by extrusion. The spout consists of a spout for discharging the contents and a shoulder for guiding the contents held in the main body to the spout.

[0184] Figure 5 This is a front view showing an example of a tube container to which the packaging film of the present disclosure is applied. Figure 5The illustrated tube container 500 comprises a main body 510 formed of a wrapping film, a spout 520 attached to one end of the main body 510, and a cap 530 attached to the spout 520. The main body 510 is a cylindrical member formed by adhering the sealing layers of the wrapping film together via a sealing portion 513 and sealing a bottom 511 at the other end opposite to the end where the spout 520 is attached, thereby enabling the container to contain the contents. The spout 520 comprises a spout 522 for discharging the contents and a shoulder 521 for guiding the contents held in the main body 510 into the spout 522. The cap 530 is a member capable of closing and opening the opening of the spout 522.

[0185] The packaging film disclosed herein has gas barrier properties and excellent abuse resistance, and is therefore suitable for use in the main body of the above-mentioned tube container that is repeatedly bent and curved when the contents are squeezed out. The packaging film disclosed herein can be used as a tube container, i.e., the main body of a laminated tube. The layer structure of the main body of the laminated tube can be, for example, a layer structure in which a first resin layer (sealing layer), an adhesive layer, a gas barrier layer, a resin substrate, an adhesive layer, and a second resin layer (sealing layer) are sequentially arranged from the innermost layer, or a layer structure in which a second resin layer (sealing layer), an adhesive layer, a resin substrate, a gas barrier layer, an adhesive layer, and a first resin layer (sealing layer) are sequentially arranged from the innermost layer. Here, an inorganic oxide layer and an undercoat layer can be sequentially arranged between the gas barrier layer and the resin substrate starting from the gas barrier layer side.

[0186] The printed layer can be provided on one side of the second resin layer and adhered to the resin substrate via an adhesive layer, or it can be provided on one side of the first resin layer and adhered to the resin substrate via an adhesive layer and a gas barrier layer. Alternatively, rather than using the first or second outermost resin layer as a sealant, it can be formed as a resin layer identical to the resin substrate, which is not heat-sealed. The innermost sealants can be adhered to each other at the end (sealing portion) of the packaging film, thereby forming the main body of the tube container into a cylindrical shape. In this case, since a sealant is not required for the outermost layer, a high-density polyethylene or polypropylene resin can be selected as the outermost layer material, thereby improving the durability and aesthetics of the tube container.

[0187] Furthermore, since the sealant layer typically requires a thickness of 60 to 100 μm, using a resin substrate (approximately 20 to 30 μm thick) as the outermost layer, rather than the sealant layer, can significantly reduce the amount of plastic used in the entire tube container. In a layer configuration where the first resin layer is the innermost sealant layer, by omitting the second resin layer and using the resin substrate as the outermost layer, the amount of plastic used in the entire tube container can be further reduced. In this case, the printed layer can be formed on the outermost resin substrate and protected by an overprint varnish.

[0188] In tube containers without a sealant layer as the outermost layer, the thickness of the laminate constituting the main body is thinner than in tube containers with sealants on both sides of the laminate. Therefore, it is believed that the stress applied to the gas barrier layer during bending is relatively greater. However, the packaging film disclosed herein exhibits gas barrier properties and excellent abuse resistance, making it suitable for tube containers without a sealant layer as the outermost layer.

[0189] To ensure that the contents can be squeezed out to the very end, the tube container may have a shoulder portion perpendicular to the main body's extension direction, rather than a tapered shape. In packaging films, using the same resin for the resin base and sealant layer can improve reusability. While the material of the tube container's spout and lid is not particularly limited, using the same resin as the resin base further improves reusability. In tube containers, a peelable film is sometimes attached to the outside of the spout to seal the opening until the first opening. The packaging film disclosed herein can also be used in combination with a peelable sealant as a lid material for sealing such an opening.

[0190] Example

[0191] Hereinafter, the present disclosure will be specifically described with reference to examples, but the present disclosure is not limited to these examples.

[0192] <Preparation of coating solution>

[0193] Coating liquids 1 to 14 as compositions for forming a gas barrier layer used in Examples or Comparative Examples were prepared as follows.

[0194] (Coating liquid 1)

[0195] An aqueous dispersion of a polyurethane resin (A1) as an aqueous dispersion of a polyurethane resin (A), an aqueous solution containing polyacrylic acid (PAA) as a water-soluble polymer (WSP), and epoxysilane as a curing agent (CA) were mixed so that the mass ratio of the polyurethane resin (PU), PAA, epoxysilane, and inorganic layered mineral (IM) as the solid components of the polyurethane resin (A) (PU:WSP:CA:IM) was 60:25:15:0. The mixture was then diluted with water and isopropyl alcohol to a solid content concentration of 5% by mass. At this time, the isopropyl alcohol content in the entire liquid was 10% by mass. Thus, a coating liquid 1 was prepared.

[0196] (Coating liquid 2)

[0197] Coating liquid 2 was prepared in the same manner as in coating liquid 1 except that the PAA aqueous solution was replaced with a polyvinyl alcohol (PVA) aqueous solution and the epoxy silane was replaced with aminosilane.

[0198] (Coating liquid 3)

[0199] Coating liquid 3 was prepared in the same manner as in coating liquid 1 except that the PAA aqueous solution was changed to a PVA aqueous solution.

[0200] (Coating liquid 4)

[0201] Coating liquid 4 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 75:20:5:0.

[0202] (Coating liquid 5)

[0203] Coating liquid 5 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 45:35:20:0.

[0204] (Coating liquid 6)

[0205] Coating liquid 6 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution and epoxysilane were not used and the mass ratio of the polyurethane resin, PAA, epoxysilane, and inorganic layered mineral as solid components (PU:WSP:CA:IM) was 100:0:0:0.

[0206] (Coating liquid 7)

[0207] Coating liquid 7 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution, the aqueous dispersion of the polyurethane resin and epoxy silane were not used, and the mass ratio of the polyurethane resin, PVA, epoxy silane, and inorganic layered mineral as solid components (PU:WSP:CA:IM) was adjusted to 0:100:0:0.

[0208] (Coating liquid 8)

[0209] Coating liquid 8 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution, epoxy silane was not used, and the polyurethane resin, PVA, epoxy silane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 65:35:0:0.

[0210] (Coating liquid 9)

[0211] Coating liquid 9 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 75:15:10:0.

[0212] (Coating liquid 10)

[0213] Coating liquid 10 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 55:40:5:0.

[0214] (Coating liquid 11)

[0215] Coating liquid 11 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 80:20:0:0.

[0216] (Coating liquid 12)

[0217] Coating liquid 12 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 60:25:10:5.

[0218] (Coating liquid 13)

[0219] Coating liquid 13 was prepared in the same manner as coating liquid 1 except that the PAA aqueous solution was replaced with a PVA aqueous solution and the polyurethane resin, PVA, epoxysilane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 60:25:14:1.

[0220] (Coating liquid 14)

[0221] Coating liquid 14 was prepared in the same manner as coating liquid 1, except that the PAA aqueous solution was replaced with a PVA aqueous solution, the "aqueous dispersion of polyurethane resin (A)" was replaced with the "aqueous dispersion of polyurethane resin (A1)" to the "aqueous dispersion of polyurethane resin (A2)", and the polyurethane resin, PVA, epoxy silane, and inorganic layered mineral as solid components were mixed so that the mass ratio (PU:WSP:CA:IM) was 60:25:15:0.

[0222] Specifically, the following substances were used as the aqueous dispersion of the polyurethane resin (A), the water-soluble polymer (B), the curing agent (C), and the inorganic layered mineral (D).

[0223] (Aqueous dispersion of polyurethane resin (A))

[0224] Aqueous dispersion of polyurethane resin (A1)

[0225] An aqueous dispersion of a polyurethane resin obtained by dispersing a solid component (polyurethane resin (A1)) in an aqueous medium composed of water (aqueous polyurethane dispersion, trade name "TAKELAC (registered trademark) WPB-341", manufactured by Mitsui Chemicals, Inc., solid content concentration: 30% by mass, polyurethane resin (A1): a reaction product of an acid group-containing polyurethane resin and a polyamine compound)

[0226] Aqueous dispersion of polyurethane resin (A2)

[0227] An aqueous dispersion of a polyurethane resin obtained by dispersing a solid component (polyurethane resin (A2)) in an aqueous medium composed of water (trade name "HYDRAN HW350", manufactured by DIC Corporation, solid content concentration: 30% by mass, polyurethane resin (A2): a polyurethane resin (polyester polyurethane resin) not corresponding to a reaction product of an acid group-containing polyurethane resin and a polyamine compound)

[0228] (B) Water-soluble polymers

[0229] (B1) Polyvinyl alcohol (PVA) aqueous solution

[0230] An aqueous solution of polyvinyl alcohol having a saponification degree of 98 to 99% and a polymerization degree of 500 (trade name "POVAL PVA-124", manufactured by Kuraray Co., Ltd., solid content concentration: 5% by mass)

[0231] (B2) Polyacrylic acid (PAA) aqueous solution

[0232] Aqueous solution of polyacrylic acid (trade name "ARON A-10H", manufactured by Toagosei Co., Ltd., solid content concentration: 25% by mass)

[0233] (C) Curing agent

[0234] (C1) Aminosilane

[0235] N-2-(Aminoethyl)-3-aminopropylmethyltrimethoxysilane (trade name "KBM-603", manufactured by Shin-Etsu Chemical Co., Ltd.)

[0236] (C2) Epoxy silane

[0237] 3-Glycidoxypropyltrimethoxysilane (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.)

[0238] (D) Inorganic layered minerals

[0239] Synthetic mica (trade name "SOMACIF (registered trademark) MEB-3", manufactured by Katakura & Co-op Agri Corporation)

[0240] <Preparation of base layer-forming composition>

[0241] The base layer-forming composition was prepared as follows.

[0242] Acrylic polyol and toluene diisocyanate were mixed so that the number of NCO groups in the toluene diisocyanate was equal to the number of OH groups in the acrylic polyol, and diluted with ethyl acetate to a total solid content (the total amount of acrylic polyol and toluene diisocyanate) of 5% by mass. β-(3,4-epoxycyclohexyl)trimethoxysilane was further added to the diluted mixture to a total solid content of 5 parts by mass relative to a total of 100 parts by mass of the acrylic polyol and toluene diisocyanate, and these were mixed to prepare a base layer-forming composition (anchor coating agent).

[0243] <Production of Gas Barrier Film>

[0244] (Example 1)

[0245] A gas barrier film was produced in a roll-to-roll process as follows: First, a 20 μm thick polypropylene resin layer (trade name "U-1", biaxially oriented film, manufactured by Mitsui Chemicals Tohcello, Inc.) serving as a resin substrate was mounted on a roll-out device, a conveyor device, and a roll-up device.

[0246] Next, the base layer-forming composition prepared in the above manner was applied to one surface of the resin substrate being transported by gravure coating to form a coating film. The coating film was then dried by heating at 120°C for 10 seconds to form a base layer having a thickness of 40 nm, thereby obtaining a laminate. The resulting laminate was wound up using a winding device to obtain a rolled laminate.

[0247] Next, the rolled laminate was mounted on a roll-out device, a conveying device, and a winding device. The laminate was then unwound from the rolled laminate, and AlO was formed on the base layer of the laminate being conveyed to a thickness of 50 nm. x Film (inorganic oxide layer). At this time, AlO x The film was formed by using a vacuum evaporation device with electron beam heating to evaporate the aluminum ingot by electron beam heating while simultaneously introducing oxygen gas to a pressure of 1.2×10 -2 Pa.

[0248] In the AlO x Coating liquid 1 was applied to the film and heated and dried to form a gas barrier layer having a thickness of 400 nm as shown in Table 1. Heating was performed to cure the polyurethane resin, PAA, and epoxy silane that constitute the solid components of coating liquid 1 to form a cured product, while simultaneously removing the liquid from the coating liquid 1. Specifically, the heating temperature was set to 60°C.

[0249] As described above, a gas barrier film in which the resin substrate, the underlayer, the inorganic oxide layer, and the gas barrier layer were laminated in this order was obtained.

[0250] (Examples 2 to 11 and Comparative Examples 1 to 8)

[0251] A gas barrier film was produced in the same manner as in Example 1 except that the resin substrate was composed of the materials shown in Table 1 or Table 2, the inorganic oxide layer was composed of the metal oxides shown in Table 1 or Table 2, the coating liquid shown in Table 1 or Table 2 was used to form the gas barrier layer, and the thickness of the gas barrier layer was set as shown in Table 1 or Table 2. xIn the case of the structure, silicon dioxide was used as the SiO deposition material instead of the aluminum ingot evaporated by electron beam heating. In Example 10, polyethylene terephthalate resin (PET) with a thickness of 12 μm was used as the resin substrate.

[0252] <Evaluation of Gas Barrier Film>

[0253] The gas barrier films obtained in Examples 1 to 11 and Comparative Examples 1 to 8 were evaluated for oxygen barrier properties and water vapor barrier properties after retorting, abuse resistance, and lamination strength after retorting as follows.

[0254] (Production of Laminated Film)

[0255] First, in order to perform these evaluations, a laminated film was produced as follows.

[0256] That is, a two-component adhesive (trade name "A-525 / A-52", manufactured by Mitsui Chemicals, Inc.) was used to adhere a 60 μm thick unstretched polypropylene film (CPP, trade name "Torayfan ZK207", manufactured by Toray Advanced Film Co., Ltd.) to the surface of the resin substrate of the gas barrier film obtained in Examples 1 to 11 and Comparative Examples 1 to 8 to produce a laminated film.

[0257] (1) Evaluation of oxygen barrier properties and water vapor barrier properties after retort treatment

[0258] (Preparation of test samples)

[0259] In order to evaluate the oxygen barrier properties and water vapor barrier properties after retorting, test samples were prepared as follows.

[0260] First, a three-sided bag with an opening was made using the laminated film prepared as described above. The three-sided bag was formed by bending the laminated film so that the unstretched polypropylene films faced each other and then heat-fusing the unstretched polypropylene films. Tap water was then poured through the opening and the opening of the three-sided bag was sealed, thereby preparing a sealed body. This sealed body was then heated (retorted) at 121°C for 30 minutes. This produced a test sample.

[0261] (Determination of oxygen permeability)

[0262] The oxygen permeability (unit: cc / m2) of the test sample was measured using an oxygen permeability measuring device (product name "OX-TRAN 2 / 20", manufactured by MOCON) at a temperature of 30°C and a relative humidity of 70%. 2·day·atm). Measurements were performed in accordance with JIS K-7126-2. The results are shown in Tables 1 and 2. Note that for Comparative Example 7, delamination was observed in the test sample, making oxygen permeability measurement impossible. Therefore, the value is indicated as "unmeasurable" in Table 2.

[0263] (Determination of water vapor transmission rate)

[0264] The water vapor transmission rate (unit: g / m2) of the test sample was measured using a water vapor transmission rate measuring device (product name "PERMATRAN 3 / 31", manufactured by MOCON) at a temperature of 40°C and a relative humidity of 90%. 2 · days). In this case, the measurement was performed in accordance with JIS K-7129. The results are shown in Tables 1 and 2. Note that for Comparative Example 7, delamination was observed in the test sample, making it impossible to measure the water vapor permeability. Therefore, it is indicated as "unmeasurable" in Table 2.

[0265] (Evaluation of oxygen barrier properties)

[0266] The oxygen barrier properties of the test samples were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0267] (Benchmark)

[0268] ○: Oxygen permeability less than 2cc / m 2 ·day·atm.

[0269] △: Oxygen permeability is 2cc / m 2 ·Day·Above atm and less than 3cc / m 2 ·day·atm.

[0270] ×: Oxygen permeability: 3cc / m 2 ·day·atm or more

[0271] (Evaluation of water vapor barrier properties)

[0272] The water vapor barrier properties of the test samples were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0273] (Benchmark)

[0274] ○: Water vapor permeability is less than 1g / m 2 ·sky.

[0275] △: Water vapor permeability is 1g / m 2 More than 2 days and less than 2g / m 2 ·sky.

[0276] ×: Water vapor permeability is 2 g / m 2 More than one day.

[0277] (2) Evaluation of abuse resistance

[0278] (Gelbo flex test)

[0279] First, in order to evaluate the abuse resistance of the gas barrier film, the laminated film produced as described above was subjected to a Gelbo flex test.

[0280] Specifically, a cylindrical body was prepared so that the laminated film produced as described above would have a cylindrical shape of 87.5 mm in diameter and 210 mm in diameter. A Gelbo flex tester (product name: "Gelbo flex tester," manufactured by Tester Sangyo Co., Ltd.) was then prepared, and the cylindrical body was mounted on a fixed head to hold both ends of the cylindrical body. The initial gripping interval was set to 175 mm, and the stroke was set to 87.5 mm. The cylindrical body was bent by repeated 440-degree twisting motions performed 10 times at a speed of 40 times / minute. This was done.

[0281] The oxygen permeability and water vapor permeability of the laminated film after the Gelbo flex test were then measured in the same manner as in the evaluation of oxygen barrier properties and water vapor barrier properties after the retort treatment.

[0282] Next, based on the oxygen permeability and the water vapor permeability, the oxygen barrier properties and the water vapor barrier properties were evaluated as follows.

[0283] (Evaluation of oxygen barrier properties)

[0284] The oxygen barrier properties were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0285] (Benchmark)

[0286] ○: Oxygen permeability less than 10cc / m 2 ·day·atm.

[0287] △: Oxygen permeability is 10cc / m 2 ·Day·Above atm and less than 15cc / m 2 ·day·atm.

[0288] ×: Oxygen permeability: 15cc / m 2 ·day·atm or more

[0289] (Evaluation of water vapor barrier properties)

[0290] The water vapor barrier properties were evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0291] (Benchmark)

[0292] ○: Water vapor permeability is less than 1.5g / m 2 ·sky.

[0293] △: Water vapor permeability is 1.5g / m 2 More than 2.5g / m 2 ·sky.

[0294] ×: Water vapor permeability is 2.5 g / m 2 More than one day.

[0295] (Determination of whether the abuse resistance is qualified or not)

[0296] Regarding abuse resistance, the laminated film was judged to be acceptable if at least one of the oxygen barrier property and the water vapor barrier property after the Gelbo flex test was evaluated as 0 or Δ.

[0297] (3) Evaluation of laminate strength after retorting

[0298] (Determination of lamination strength)

[0299] First, with respect to the above-mentioned test samples, the lamination strength was measured as follows.

[0300] Specifically, the lamination strength of the test samples was measured in accordance with JIS Z-1707. Specifically, the test samples were first cut into 15 mm wide strips. Next, using a universal tensile testing machine (product name "Tensilon RTC-1250," manufactured by Orientec Corporation), the gas barrier film of the test sample was peeled from the CPP film at a peeling speed of 300 mm / min, with the gas barrier film and the CPP film facing opposite sides (i.e., a T-shaped peel angle). The strength required for the peeling (unit: N / 15 mm) was measured as the lamination strength.

[0301] (Evaluation of lamination strength)

[0302] The lamination strength was evaluated according to the following criteria. The results are shown in Tables 1 and 2.

[0303] (Benchmark)

[0304] ○: Lamination strength is 2N / 15mm or more.

[0305] △: Lamination strength is 1.5 N / 15 mm or more and less than 2 N / 15 mm.

[0306] ×: Lamination strength is less than 1.5 N / 15 mm.

[0307] (Determination of whether the lamination strength is qualified or not)

[0308] When the evaluation level of the lamination strength after the retort treatment was 0 or △, it was judged to be acceptable.

[0309] (4) Evaluation of exudation inhibition effect

[0310] The surfaces of the gas barrier films of Examples 1 to 11 and Comparative Examples 1 to 8 were observed visually and by touch. The bleed-out suppression effect was evaluated according to the following criteria. A bleed-out suppression effect of 0 was considered acceptable.

[0311] (Benchmark)

[0312] ○: No bleeding was observed on the surface of the gas barrier film

[0313] ×: Bleeding of the curing agent was observed on the surface of the gas barrier film, and tackiness was also confirmed.

[0314] (5) Evaluation related to reusability

[0315] Regarding recyclability, the single-cycle ratio of the laminated film obtained as described above was calculated based on the following formula, and the film was evaluated based on the single-cycle ratio and the following criteria.

[0316] Single cycle ratio (%)

[0317] =100×

[0318] (Thickness of the resin substrate composed of PP × specific gravity + thickness of the CPP layer × specific gravity) /

[0319] (Thickness of resin substrate × specific gravity

[0320] + thickness of base layer × specific gravity

[0321] + thickness of metal oxide layer × specific gravity

[0322] +Thickness of gas barrier film×specific gravity

[0323] + thickness of adhesive × specific gravity

[0324] + thickness of CPP layer × specific gravity)

[0325] (Benchmark)

[0326] ○: Single cycle ratio is 90% or more ×: Single cycle ratio is less than 90%

[0327]

[0328]

[0329] As shown in Tables 1 and 2, the gas barrier films of Examples 1 to 11 all met the acceptable standards for abuse resistance, lamination strength after retorting, and bleed-out suppression. On the other hand, the gas barrier films of Comparative Examples 1 to 8 failed to meet the acceptable standards for at least one of these: abuse resistance, lamination strength after retorting, and bleed-out suppression.

[0330] From the above, it was confirmed that the gas barrier layer-forming composition of the present disclosure can impart excellent abuse resistance to a gas barrier film, impart high lamination strength even after retort treatment, and suppress bleed-out.

[0331] Explanation of symbols

[0332] 1 ...resin substrate, 4 ...gas barrier layer, 10 ...gas barrier film, 20 ...packaging film, 21 ...sealing layer, 30 ...packaging bag, 100 ...packaging bag with stopper, 104 ...stopper, 105 ...straw, 140 ...packaging bag, 500 ...tube container, 510 ...main body, 520 ...spout, 530 ...cap.

Claims

1. A composition for forming a gas barrier layer, comprising a solid component containing a polyurethane resin (A), a water-soluble polymer (B) and a curing agent (C), The polyurethane resin (A) comprises a reaction product of an acid group-containing polyurethane resin containing an acid group and a polyamine compound having an amino group. The content of the polyurethane resin (A) in the solid component is 45% by mass or more and 60% by mass or less, The content of the water-soluble polymer (B) in the solid component is 20% by mass or more and 25% by mass or less, and The content of the inorganic layered mineral (D) in the solid component is less than 2% by mass. The water-soluble polymer (B) does not have a silanol group.

2. The composition for forming a gas barrier layer according to claim 1, wherein The content of the inorganic layered mineral (D) in the solid component is 0% by mass, and the total content of the polyurethane resin (A), the water-soluble polymer (B), and the curing agent (C) in the solid component is 100% by mass.

3. The composition for forming a gas barrier layer according to claim 1 or 2, wherein The content of the curing agent (C) in the solid content is 20% by mass or less.

4. The composition for forming a gas barrier layer according to claim 1 or 2, wherein The content of the curing agent (C) in the solid content is 5% by mass or more.

5. The composition for forming a gas barrier layer according to claim 1 or 2, wherein The water-soluble polymer (B) is polyvinyl alcohol resin or a modified form thereof. The composition for forming a gas barrier layer according to claim 1 or 2, wherein The water-soluble polymer (B) is a polyvinyl alcohol resin, which is composed of a homopolymer of vinyl alcohol or a vinyl alcohol-vinyl acetate copolymer.

7. The composition for forming a gas barrier layer according to claim 1 or 2, wherein The curing agent (C) contains an epoxy group. 8 . A gas barrier film comprising: a resin substrate; and a gas barrier layer provided on one surface of the resin substrate and composed of a cured product of the gas barrier layer-forming composition according to claim 1 .

9. The gas barrier film according to claim 8, wherein The thickness of the gas barrier layer is less than 800 nm.

10. The gas barrier film according to claim 8 or 9, wherein The thickness of the gas barrier layer is greater than 150 nm.

11. The gas barrier film according to claim 8 or 9, An inorganic oxide layer containing an inorganic oxide is further provided between the resin substrate and the gas barrier layer.

12. The gas barrier film according to claim 11, wherein The inorganic oxide is composed of silicon oxide.

13. A packaging film comprising: The gas barrier film according to any one of claims 8 to 12, and A sealant layer is laminated on the gas barrier film. 14 . A packaging bag formed by using the packaging film according to claim 13 and bonding the sealing layers to each other.

15. A method for producing a gas barrier film comprising: a resin substrate and a gas barrier layer provided on one surface of the resin substrate; A gas barrier layer forming step of producing the gas barrier film by curing the gas barrier layer-forming composition according to any one of claims 1 to 7 on one surface side of the resin substrate to form the gas barrier layer.

16. A method for manufacturing a packaging film, comprising: a gas barrier film manufacturing process of manufacturing a gas barrier film by the method for manufacturing a gas barrier film according to claim 15; and A sealant layer laminating step is performed by laminating a sealant layer on the gas barrier film to obtain a packaging film.

17. A method for manufacturing a packaging bag, comprising: A packaging film manufacturing process of manufacturing a packaging film by the packaging film manufacturing method according to claim 16; and A packaging film bonding process is performed to manufacture a packaging bag by bonding the sealing layers to each other using the packaging film.

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