Gas barrier laminate film

Abstract

The present disclosure addresses the problem of providing a gas barrier laminate film that uses a gas barrier base film having an inorganic thin film layer, has improved gas barrier properties as well as excellent post-bending barrier properties, and has excellent recyclability.　A gas barrier laminate film according to the present disclosure has first and second base films and an adhesive layer disposed therebetween, wherein at least one of the first and second base films has an inorganic thin film layer formed on the outermost surface layer, and the inorganic thin film layer and the adhesive layer are in contact with each other. The gas barrier laminate film is characterized in that, when a portion formed by the base film and the inorganic thin film layer on the outermost surface thereof is referred to as a gas barrier base film, the water vapor permeability (W1) of the gas barrier base film and the water vapor permeability (W2) of the gas barrier laminate film satisfy expression 1.　Expression 1: 100-\{(W2 / W1)×100\} ≥ 60

Description

Gas barrier laminate film

[0001] This disclosure relates to gas barrier laminate films used in packaging fields for food, pharmaceuticals, industrial products, etc., or gas barrier laminate films used inside electronic components. More specifically, it relates to a gas barrier laminate film obtained by laminating a gas barrier substrate film, which comprises a base film and an inorganic thin film layer, to a base film, wherein the gas barrier properties can be improved by lamination.

[0002] Packaging materials used for food, pharmaceuticals, and other products are required to possess gas barrier properties, meaning they can block gases such as oxygen and water vapor, in order to protect the contents. Furthermore, gas barrier materials used in electronic devices and displays such as quantum dots and organic EL displays are required to have even higher gas barrier properties than those used for food and pharmaceutical packaging materials.

[0003] In gas barrier materials, gas barrier substrate films are known that have a gas barrier layer on the surface of a plastic substrate film. As the gas barrier layer, inorganic thin films made of metals or metal oxides formed by vacuum deposition are widely used.

[0004] Gas barrier substrate films are rarely used on their own; they are more commonly used as printed materials or laminated with other films. Therefore, gas barrier substrate films are required to maintain their gas barrier properties even after printing or lamination. However, gas barrier substrate films with an inorganic thin film layer on the outermost layer are susceptible to deterioration of their gas barrier properties due to even minor scratches or abrasions, posing a challenge in that their gas barrier properties deteriorate during the processing stage. Furthermore, it has been pointed out that the gas barrier properties are insufficient for applications such as electronic devices, displays, and packaging materials requiring high gas barrier performance, using only an inorganic thin film layer produced by vacuum deposition.

[0005] To address the above problem, attempts have been made to provide a protective layer on top of an inorganic thin film layer. For example, Patent Document 1 proposes a method of forming a protective layer made of organic resin on top of an inorganic thin film layer by coating it with urethane resin. This method has been shown to not only protect the inorganic thin film layer but also to improve the barrier effect of the coating layer due to the aggregation of the urethane resin. However, it has been found that the flexibility is insufficient, and when used as a packaging material, the gas barrier properties deteriorate after the Gelboflex test, which presents a technical challenge.

[0006] Furthermore, laminated films, such as those proposed in Patent Document 1, are generally used by laminating them with films made of different materials in order to satisfy their functions as packaging materials (gas barrier properties, heat resistance, toughness (resistance to tearing and pinholes), and sealing properties). However, because they are laminated with different materials, they have the problem of being poorly recyclable.

[0007] Patent No. 6794633

[0008] Thus, in the above-mentioned Patent Document 1, although the presence of a protective layer improves gas barrier properties, the flexibility is insufficient, and problems may arise such as deterioration of gas barrier properties during use as a packaging material, or difficulty in recycling due to lamination with different materials.

[0009] This disclosure is made against the backdrop of the aforementioned prior art, and aims to provide a gas barrier laminate film that uses a gas barrier substrate film having an inorganic thin film layer, improves gas barrier properties, exhibits excellent barrier properties after bending, and has excellent recyclability.

[0010] The inventors have discovered that by laminating an inorganic thin film layer of a gas barrier substrate film into contact with an adhesive layer, it is possible to obtain a gas barrier laminate film that has excellent gas barrier properties, excellent barrier properties after bending, and a high monomaterial ratio, thereby completing the gas barrier laminate film according to the present disclosure.

[0011] In other words, the present disclosure consists of the following configurations: (1) A gas barrier laminate film having first and second base films and an adhesive layer interposed between them, wherein at least one of the first and second base films has an inorganic thin film layer formed on its outermost surface, and the inorganic thin film layer and the adhesive layer are in contact, and the portion formed from the base film and the inorganic thin film layer on its outermost surface is referred to as the gas barrier base film, characterized in that the water vapor permeability (W1) of the gas barrier base film and the water vapor permeability (W2) of the gas barrier laminate film satisfy the following formula 1. Formula 1: 100 - {(W2 / W1) × 100} ≥ 60 (2) The gas barrier laminate film according to (1) wherein the inorganic thin film layer contains one or more selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide. (3) The gas barrier laminate film according to (1) or (2) above, wherein the adhesive comprises one or more selected from the group consisting of polyurethane resins, polyester resins, epoxy resins, poly(meth)acrylic resins, polyol resins, and copolymer resins thereof. (4) The gas barrier laminate film according to any one of (1) to (3) above, wherein a coating layer is provided between at least one of the first and second base films and the inorganic thin film layer, and the coating layer comprises one or more selected from the group consisting of polyester resins and polyurethane resins. (5) The water vapor transmission rate (W2) of the gas barrier laminate film is 1.0 g / m². 2 A gas barrier laminate film according to any one of (1) to (4) above, wherein the water vapor transmission rate (W3) of the gas barrier laminate film after bending treatment is 3.0 g / m 2(1) to (5) above, wherein the oxygen permeability (O1) of the gas barrier substrate film and the oxygen permeability (O2) of the gas barrier laminate film satisfy the following formula 2. Formula 2: 100 - {(O2 / O1) × 100} ≥ 60 (8) The oxygen permeability (O3) of the gas barrier laminate film after bending treatment is 10 ml / m² 2 (1) to (2) above, a gas barrier laminate film having a pressure of 1 / day / MPa or less. (9) A gas barrier laminate film according to any one of (1) to (2) above, wherein both the first and second base films are polyester films. (10) A gas barrier laminate film according to any one of (1) to (2) above, wherein the gas barrier laminate film is heat-sealable. (11) A gas barrier laminate film according to any one of (1) to (2) above, wherein both the first and second base films are polypropylene films. (12) A gas barrier laminate film according to (11) above, wherein at least one of the first and second base films has a base layer and a surface layer, and the base layer and the surface layer contain one or both of a polypropylene homopolymer and a polypropylene copolymer. (13) A food packaging material using a gas barrier laminate film according to any one of (1) to (2) above.

[0012] According to this disclosure, it is possible to provide a gas barrier laminate film that uses a gas barrier substrate film having an inorganic thin film layer, which improves gas barrier properties, exhibits excellent barrier properties after bending, and has excellent recyclability. Furthermore, according to this disclosure, by laminating the film in a way that maximizes the sealing effect of the adhesive, the gas barrier properties of the inorganic thin film layer of the gas barrier substrate film can be further improved, the processing steps can be simplified, and a gas barrier laminate film that is easy to handle in subsequent processing can be obtained.

[0013] The gas barrier laminate film according to this disclosure comprises first and second base films and an adhesive layer interposed between them, wherein at least one of the first and second base films has an inorganic thin film layer formed on its outermost surface, and the inorganic thin film layer and the adhesive layer are in contact. When the portion formed from the base film and the inorganic thin film layer on its outermost surface is referred to as the gas barrier base film, the water vapor permeability (W1) of the gas barrier base film and the water vapor permeability (W2) of the gas barrier laminate film satisfy the following formula 1: Formula 1: 100 - {(W2 / W1) × 100} ≥ 60 Thus, the gas barrier laminate film of this disclosure is formed by bonding a first base film, on which an inorganic thin film layer is provided on at least one side, to a second base film via an adhesive. The first base film and the inorganic thin film layer, followed by the second base film and the layers that can be laminated thereon will be described below. Furthermore, the adhesive layer used to bond the two base films will be described. Note that gas barrier properties refer to barrier properties against water vapor or oxygen, and may also have barrier properties against other gases (e.g., carbon dioxide). In this disclosure, the numerical notation "〇〇 or more and □□ or less" is synonymous with the notation "〇〇 to □□," and both have the same meaning.

[0014] [First Substrate Film] As the first substrate film used in this disclosure, for example, a film can be used which is obtained by melt-extruding a plastic and, if necessary, stretching in the longitudinal and / or widthwise directions, cooling, and heat-setting. Examples of plastics include polyesters represented by polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, etc.; polyamides represented by nylon 4・6, nylon 6, nylon 6・6, nylon 12, etc.; polyolefins represented by polyethylene, polypropylene, polybutene, etc.; as well as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, fully aromatic polyamides, polyamide-imides, polyimides, polyetherimides, polysulfones, polystyrene, polylactic acid, etc. Among these, polyester is preferred in terms of heat resistance, dimensional stability, and transparency, and polyethylene terephthalate and copolymers obtained by copolymerizing polyethylene terephthalate with other components are particularly preferred. Polyolefins are also preferred in terms of heat sealability, and polypropylene homopolymers and polypropylene copolymers are particularly preferred. In other words, the first base film is preferably a polyester film or a polyolefin film, and more preferably a polyethylene terephthalate film or a polypropylene film. The first base film may have a heat-seal layer made of the same plastic as the first base film on at least one of its outermost surfaces. The first base film may also be an unoriented film, a uniaxially oriented film, or a biaxially oriented film, and is preferably a biaxially oriented film.

[0015] The first base film can have any thickness depending on the desired purpose and application, such as mechanical strength and transparency. The thickness is not particularly limited, but is preferably in the range of 5 to 250 μm, more preferably in the range of 10 to 60 μm, and even more preferably in the range of 10 to 40 μm. The transparency of the first base film is not particularly limited, but when used as a packaging material where transparency is required, it is desirable to have a light transmittance of 50% or more. The first base film may be a single-layer film made of one type of plastic, or a laminated film made by laminating two or more types of plastic films. In the case of a laminated film, the type of laminate, the number of layers, the lamination method, etc., are not particularly limited and can be arbitrarily selected from known methods depending on the purpose. Furthermore, the base film may be subjected to surface treatments such as corona discharge treatment, glow discharge treatment, flame treatment, surface roughening treatment, etc., as long as it does not impair the purpose of this disclosure, and may also be subjected to known anchor coating treatment, printing, decoration, etc.

[0016] [Inorganic Thin Film Layer] The first substrate film has an inorganic thin film layer on its outermost surface.

[0017] The inorganic thin film layer is preferably a thin film made of a metal or an inorganic oxide of a metal. The material for forming the inorganic thin film layer is not particularly limited as long as it can form a thin film, and examples include metals such as aluminum, silicon, titanium, zinc, zirconium, magnesium, tin, copper, and iron, and oxides, nitrides, etc. of these metals, and mixtures of these may also be used. It is preferable that the inorganic thin film layer contains one or more selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide. From the viewpoint of gas barrier properties, inorganic oxides such as silicon oxide (silica), aluminum oxide (alumina), and a mixture of silicon oxide and aluminum oxide are preferably mentioned. In particular, from the viewpoint of achieving both flexibility and denseness of the thin film layer, a composite oxide of silicon oxide and aluminum oxide is more preferable. Regarding the mixing ratio of silicon oxide and aluminum oxide, the Al ratio is preferably in the range of 20 to 70% by mass, more preferably in the range of 25 to 65% by mass, and even more preferably in the range of 30 to 60% by mass, as the mass ratio of the metal component (Al / (Al + Si)×100). When the Al ratio is less than 20% by mass, the water vapor barrier property may be low. On the other hand, when the Al ratio exceeds 70% by mass, the inorganic thin film layer tends to become hard, and there is a risk that the film may be broken during secondary processing such as printing or lamination, resulting in a decrease in the barrier property. Here, the silicon oxide referred to here is various silicon oxides such as SiO and SiO2 or mixtures thereof, and the aluminum oxide is various aluminum oxides such as AlO and Al2O3 or mixtures thereof.

[0018] The film thickness of the inorganic thin film layer is not particularly limited, but is preferably in the range of 1 to 100 nm, more preferably in the range of 5 to 50 nm, even more preferably in the range of 7 to 40 nm, and even more preferably in the range of 9 to 30 nm. When the film thickness of the inorganic thin film layer is less than 1 nm, it may be difficult to obtain a satisfactory gas barrier property. On the other hand, even if it is excessively thick exceeding 100 nm, the corresponding improvement effect of the gas barrier property cannot be obtained, and it is rather disadvantageous in terms of bending resistance and manufacturing cost.

[0019] The method for forming an inorganic thin film layer is not particularly limited, and any known deposition method can be appropriately adopted, such as physical deposition methods (PVD) including vacuum deposition, sputtering, and ion plating, or chemical deposition (CVD). Below, a typical method for forming an inorganic thin film layer will be described using a silicon oxide / aluminum oxide thin film as an example. For example, when employing vacuum deposition, a mixture of SiO2 and Al2O3, or a mixture of SiO2 and Al, is preferably used as the deposition raw material. These deposition raw materials are usually particles, and it is desirable that the size of each particle is such that the pressure during deposition does not change, with a preferred particle size of 1 mm to 5 mm. For heating, methods such as resistance heating, high-frequency induction heating, electron beam heating, and laser heating can be employed. It is also possible to introduce oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, etc. as a reaction gas, or to employ reactive deposition using means such as ozone addition or ion assistance. Furthermore, the film deposition conditions can be arbitrarily changed, such as by applying a bias to the substrate (the laminated film used for deposition) or by heating or cooling the substrate. These deposition materials, reaction gases, bias, heating / cooling of the substrate can also be similarly modified when using sputtering or CVD methods.

[0020] [Second Substrate Film] As the second substrate film used in this disclosure, for example, a film can be used which is obtained by melt-extruding a plastic and, if necessary, stretching in the longitudinal and / or widthwise directions, cooling, and heat-setting. Examples of plastics include polyesters represented by polyethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, etc.; polyamides represented by nylon 4・6, nylon 6, nylon 6・6, nylon 12, etc.; polyolefins represented by polyethylene, polypropylene, polybutene, etc.; as well as polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, fully aromatic polyamides, polyamide-imides, polyimides, polyetherimides, polysulfones, polystyrene, polylactic acid, etc. Among these, polyester is preferred in terms of heat resistance, dimensional stability, and transparency, and polyethylene terephthalate and copolymers obtained by copolymerizing polyethylene terephthalate with other components are particularly preferred. Polyolefins are also preferred in terms of heat sealability, and polypropylene homopolymers and polypropylene copolymers are particularly preferred. In other words, the second base film is preferably a polyester film or a polyolefin film, and more preferably a polyethylene terephthalate film or a polypropylene film. The second base film may have a heat-seal layer made of the same plastic as the second base film on at least one of its outermost surfaces. The second base film may also be an unoriented film, a uniaxially oriented film, or a biaxially oriented film, and is preferably an unoriented film or a biaxially oriented film.

[0021] As the second base film, a film with an arbitrary thickness can be used according to desired purposes and applications such as mechanical strength and transparency, and its thickness is not particularly limited, but it is preferably in the range of 5 to 250 μm, more preferably in the range of 10 to 60 μm, and even more preferably in the range of 10 to 40 μm. The transparency of the second base film is not particularly limited, but when used as a packaging material for which transparency is required, a film having a light transmittance of 50% or more is desirable. The second base film may be a single-layer film made of one type of plastic or a laminated film in which two or more types of plastic films are laminated. The type, number of laminations, lamination method, etc. of the laminate in the case of a laminated film are not particularly limited, and can be arbitrarily selected from known methods according to the purpose. Further, the base film may be subjected to surface treatments such as corona discharge treatment, glow discharge, flame treatment, surface roughening treatment, etc., as long as the object of the present invention is not impaired, and known anchor coat treatment, printing, decoration, etc. may also be applied.

[0022] [Inorganic thin film layer] The second base film may have an inorganic thin film layer.

[0023] The inorganic thin film layer is preferably a thin film made of a metal or an inorganic oxide of a metal. The material forming the inorganic thin film layer is not particularly limited as long as it can be formed into a thin film, but examples include metals such as aluminum, silicon, titanium, zinc, zirconium, magnesium, tin, copper, and iron, as well as oxides and nitrides of these metals, and mixtures thereof may also be used. It is preferable that the inorganic thin film layer contains one or more selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide. From the viewpoint of gas barrier properties, inorganic oxides such as silicon oxide (silica), aluminum oxide (alumina), and mixtures of silicon oxide and aluminum oxide are preferred. In particular, a composite oxide of silicon oxide and aluminum oxide is more preferable from the viewpoint of achieving both flexibility and density in the thin film layer. Regarding the mixing ratio of silicon oxide and aluminum oxide, the Al ratio (Al / (Al+Si)×100) is preferably in the range of 20 to 70 mass%, more preferably in the range of 25 to 65 mass%, and even more preferably in the range of 30 to 60 mass%. If the Al ratio is less than 20% by mass, the water vapor barrier properties may be low. On the other hand, if the Al ratio exceeds 70% by mass, the inorganic thin film layer tends to harden, and there is a risk that the film will be damaged during secondary processing such as printing or lamination, reducing its barrier properties. Here, silicon oxide refers to various silicon oxides such as SiO and SiO2 or mixtures thereof, and aluminum oxide refers to various aluminum oxides such as AlO and Al2O3 or mixtures thereof.

[0024] The thickness of the inorganic thin film layer is not particularly limited, but is preferably in the range of 1 to 100 nm, more preferably in the range of 5 to 50 nm, even more preferably in the range of 7 to 40 nm, and even more preferably in the range of 9 to 30 nm. If the thickness of the inorganic thin film layer is less than 1 nm, it may be difficult to obtain satisfactory gas barrier properties, while if it is excessively thick beyond 100 nm, the corresponding improvement in gas barrier properties cannot be obtained, and it may even be disadvantageous in terms of flexibility and manufacturing costs.

[0025] The method for forming an inorganic thin film layer is not particularly limited, and any known deposition method can be appropriately adopted, such as physical deposition methods (PVD) including vacuum deposition, sputtering, and ion plating, or chemical deposition (CVD). Below, a typical method for forming an inorganic thin film layer will be described using a silicon oxide / aluminum oxide thin film as an example. For example, when employing vacuum deposition, a mixture of SiO2 and Al2O3, or a mixture of SiO2 and Al, is preferably used as the deposition raw material. These deposition raw materials are usually particles, and it is desirable that the size of each particle is such that the pressure during deposition does not change, with a preferred particle size of 1 mm to 5 mm. For heating, methods such as resistance heating, high-frequency induction heating, electron beam heating, and laser heating can be employed. It is also possible to introduce oxygen, nitrogen, hydrogen, argon, carbon dioxide, water vapor, etc. as a reaction gas, or to employ reactive deposition using means such as ozone addition or ion assistance. Furthermore, the film deposition conditions can be arbitrarily changed, such as by applying a bias to the substrate (the laminated film used for deposition) or by heating or cooling the substrate. These deposition materials, reaction gases, bias, heating / cooling of the substrate can also be similarly modified when using sputtering or CVD methods.

[0026] In this disclosure, it is preferable that both the first and second base films are polyester films. It is also preferable that both the first and second base films are polypropylene films.

[0027] In a preferred embodiment of the present disclosure, both the first and second base films are polypropylene films, and at least one of the first and second base films has a base layer and a surface layer, wherein the base layer and the surface layer preferably contain one or both of a polypropylene homopolymer and a polypropylene copolymer.

[0028] The base layer may be any layer that ensures the overall mechanical strength and heat resistance of the film, and preferably contains a polypropylene homopolymer. The surface layer may be any layer that provides surface lubricity, and preferably contains a polypropylene homopolymer and / or polypropylene copolymer and an antiblocking agent, and more preferably contains a polypropylene homopolymer and an antiblocking agent.

[0029] The polypropylene homopolymer preferably contains substantially no comonomers other than propylene (preferably ethylene and butene), and the amount of comonomers is preferably 0 mol% to 0.5 mol%, more preferably 0 mol% to 0.3 mol%, and even more preferably 0 mol% to 0.1 mol%. The polypropylene homopolymer may be used alone or in combination of two or more types.

[0030] The polypropylene homopolymer may have a predetermined mesopentad fraction, mass-average molecular weight, number-average molecular weight, and melt flow rate. The mesopentad fraction of the polypropylene homopolymer is more preferably 90-99.9%, even more preferably 92-99.9%, and even more preferably 93-99.9%. When the mesopentad fraction is within the above range, the crystallinity of the polypropylene resin increases, allowing for a base film with predetermined rigidity and heat resistance. If the mesopentad fraction is less than 90%, there is a risk of reduced flexural resistance. The mesopentad fraction is calculated according to the method described by Zamballi et al., Macromolecules, Vol. 6, p. 925 (1973), for example, 13 It can be measured using C-NMR. 13 For example, a suitable C-NMR measurement condition is to use a BRUKER AVANCE 500 and dissolve 200 mg of the sample in an 8:2 mixture of o-dichlorobenzene and deuterium benzene at 135°C, followed by measurement at 110°C.

[0031] The melt flow rate (MFR) (230°C, 2.16 kgf) of the polypropylene homopolymer is preferably 0.5 g / 10 min to 20 g / 10 min, more preferably 1.0 g / 10 min to 15 g / 10 min, even more preferably 1.5 g / 10 min to 13 g / 10 min, and even more preferably 2.0 g / 10 min to 10 g / 10 min. Within this range, the mechanical load is small, making extrusion and stretching easier.

[0032] The polypropylene homopolymer may have a predetermined mass-average molecular weight, and the mass-average molecular weight of the polypropylene resin is preferably 200,000 to 500,000, more preferably 210,000 to 450,000, and even more preferably 220,000 to 400,000. When the mass-average molecular weight is within the above range, the stretching temperature can be increased, and stretching tends to become easier.

[0033] Polypropylene homopolymers may have a predetermined number-average molecular weight, and the number-average molecular weight of polypropylene resins is preferably 30,000 to 100,000, more preferably 40,000 to 90,000, and even more preferably 50,000 to 85,000. When the number-average molecular weight is within the above range, the stretching temperature can be increased, and stretching tends to become easier.

[0034] The mass-average molecular weight and number-average molecular weight of polypropylene homopolymers are calculated using gel permeation chromatography (GPC).

[0035] The polypropylene copolymer is preferably a polypropylene resin copolymerized with ethylene and / or an α-olefin having 4 to 10 carbon atoms in an amount greater than 0.5 mol% and less than or equal to 5.0 mol%. The copolymer component of the copolymerized polypropylene resin is preferably 1.0 to 4.0 mol%, more preferably 1.5 to 3.5 mol%, and even more preferably 2.0 to 3.5 mol%. Examples of α-olefins having 4 to 10 carbon atoms include 1-butene, 1-hexene, 4-methyl-1-pentene, and 1-octene. In addition, polar maleic acid may be used as another copolymer component. The polypropylene copolymer is preferably a propylene ethylene copolymer, a propylene butene copolymer, or a propylene ethylene butene copolymer.

[0036] The base layer may contain one or more polypropylene homopolymers, and preferably contains two polypropylene homopolymers. The content of the polypropylene homopolymers constituting the base layer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and may be 100% by mass, based on 100% by mass of the resin composition constituting the base layer. The base layer preferably contains a polypropylene homopolymer (A) with an MFR of 5 g / 10 min or less and a polypropylene homopolymer (B) with an MFR of more than 5 g / 10 min. The content of the polypropylene homopolymer (A) with an MFR of 5 g / 10 min or less is preferably 15 to 85% by mass, more preferably 20 to 80% by mass, and even more preferably 25 to 75% by mass, based on 100% by mass of the resin composition constituting the base layer. The content of polypropylene homopolymer (B) with an MFR of more than 5 g / 10 min is preferably 15 to 85% by mass, more preferably 20 to 80% by mass, and even more preferably 25 to 75% by mass, of 100% by mass of the resin composition constituting the base layer.

[0037] The base layer preferably contains a polypropylene homopolymer with a mesopentad fraction of 98.5% or more, and the surface layer preferably contains a polypropylene homopolymer with a mesopentad fraction of less than 98.5%. If the base layer and the surface layer contain two or more types of polypropylene homopolymers, the smallest mesopentad fraction in the base layer should be 98.5% or more, and the largest mesopentad fraction in the surface layer should be less than 98.5%.

[0038] The surface layer may contain one or more polypropylene homopolymers or polypropylene copolymers, and it is preferable that it contains two polypropylene homopolymers. When the surface layer contains two polypropylene homopolymers, it is sufficient to use polypropylene homopolymers that differ in one or more of the following: mesopentad fraction, mass average molecular weight, number average molecular weight, or MFR. The content of the polypropylene homopolymer constituting the surface layer is preferably 80 to 100% by mass, more preferably 90 to 100% by mass, and may be substantially 100% by mass, based on 100% by mass of the resin composition constituting the surface layer.

[0039] The surface layer preferably contains particles as an antiblocking agent to form protrusions on the film surface in order to provide handling properties (e.g., windability after lamination). Examples of particles to be included in the surface layer include inorganic particles such as silica, kaolinite, talc, calcium carbonate, zeolite, and alumina, and heat-resistant polymer particles such as acrylic, PMMA, nylon, polystyrene, polyester, benzoguanamine-formaldehyde condensate, and silicone. Among these, silica and silicone particles are preferred. The particle content relative to the total mass of the surface layer is preferably, for example, 1 ppm to 4000 ppm, and more preferably 50 ppm to 3500 ppm. The preferred average particle diameter is 1.0 to 3.0 μm, and more preferably 1.0 to 2.7 μm. The method for measuring the average particle size here is to take a photograph with a scanning electron microscope, measure the horizontal Ferret diameter using an image analyzer, and display the average value. Furthermore, from the viewpoint of transparency, it is preferable to select particles with a refractive index close to that of the resin used.

[0040] When the first and second base films are composed of olefin (preferably polypropylene), possible configurations include surface layer / base layer, surface layer / base layer / surface layer, surface layer / base layer / base layer / surface layer, etc., with surface layer / base layer / surface layer being preferred.

[0041] When the first and second base films are composed of olefin (preferably polypropylene), the thickness of the first and second base films is preferably 2 to 100 μm, more preferably 3 to 90 μm, even more preferably 4 to 80 μm, even more preferably 5 to 70 μm, and particularly preferably 10 to 50 μm. If the thickness is too thin, the rigidity of the film will be low, and handling will be poor. On the other hand, if the thickness is too thick, not only will there be cost issues, but when the film is wound up in a roll for storage, poor flatness due to curling will be more likely to occur. The thickness of the base layer constituting the first and second base films is, for example, 2 to 40 μm, preferably 3 to 35 μm, more preferably 4 to 30 μm, and even more preferably 5 to 25 μm. The thickness of the surface layer constituting the first and second base films is, for example, 0.5 to 10 μm, preferably 0.7 to 7 μm, and more preferably 0.9 to 5 μm.

[0042] When the first and second base films are composed of olefin (preferably polypropylene), the first and second base films may be uniaxially oriented films or biaxially oriented films in the longitudinal direction (MD direction) or transverse direction (TD direction), with biaxial oriented films being preferred. Examples of stretching methods include simultaneous biaxial stretching and sequential biaxial stretching, but sequential biaxial stretching is preferred in terms of improving flatness, dimensional stability, and thickness uniformity. At least one of the first and second base films may be an unstretched polypropylene film.

[0043] In the sequential biaxial stretching method, an olefin (preferably polypropylene) is heated and melted in a single-screw or twin-screw extruder to a resin temperature of preferably 200 to 280°C (more preferably 210 to 270°C, and even more preferably 220 to 260°C), formed into a sheet using a T-die, and extruded onto a chill roll at a temperature of preferably 10 to 100°C (more preferably 20 to 80°C, and even more preferably 25 to 60°C) to obtain an unstretched sheet. Next, the material is roll-stretched preferably 3.0 to 8.0 times (more preferably 3.5 to 7.0 times, even more preferably 4.0 to 6.5 times) in the longitudinal direction (MD direction) at a temperature of preferably 120 to 165°C (more preferably 120 to 150°C, even more preferably 120 to 140°C), and then preheated in a tenter, and then roll-stretched preferably 4.0 to 20.0 times (more preferably 5.0 to 15 times, even more preferably 6.0 to 14 times, even more preferably 7.0 to 10 times) in the width direction (TD direction) at a temperature of preferably 150 to 175°C (more preferably 152 to 170°C, even more preferably 154 to 165°C, even more preferably 155 to 164°C, particularly preferably 156 to 164°C). Furthermore, after biaxial stretching, a heat-setting treatment can be performed at a temperature of preferably 165 to 180°C (more preferably 167 to 178°C, even more preferably 169 to 176°C) while allowing a relaxation of preferably 1 to 15% (more preferably 2 to 12%, even more preferably 3 to 10%).

[0044] The gas barrier laminate film of this disclosure uses an adhesive to bond a first substrate film and a second substrate film together.

[0045] [Adhesive Layer] Known dry laminating adhesives can be used as the adhesive. For example, any adhesive consisting of polyurethane resin, poly(meth)acrylic resin, polyester resin, epoxy resin, polyol resin, or copolymer resin of these resins can be used. Preferably, the adhesive contains one or more selected from the group consisting of polyurethane resin, polyester resin, epoxy resin, poly(meth)acrylic resin, polyol resin, and copolymer resin thereof; more preferably, it contains one or more selected from the group consisting of polyurethane resin, polyester resin, and epoxy resin; and even more preferably, it contains polyurethane resin or epoxy resin. The adhesive may be used alone or in combination of two or more types.

[0046] By contacting the adhesive, the inorganic thin film layer can be prevented from being exposed to the outside, making it less susceptible to external physical effects and thus reducing the deterioration of its gas barrier properties. Furthermore, although the inorganic thin film layer has minute defects, contact with the adhesive creates a sealing effect, which is expected to further improve its gas barrier properties. In this case, selecting an adhesive with high cohesive strength, i.e., a gas barrier adhesive, can further enhance the sealing effect. The adhesive is preferably a gas barrier adhesive. In this disclosure, a gas barrier adhesive means an adhesive that, in addition to its adhesive function for bonding adherends, has gas barrier properties that suppress the permeation of gases such as water vapor, oxygen, and carbon dioxide. Examples of gas barrier adhesives include ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA), polyamide resins, polyurethane resins, epoxy resins, or mixtures thereof. Alternatively, a resin in which inorganic oxide fine particles (e.g., silica, alumina) are dispersed may be used. When a polyurethane resin is used as the gas barrier adhesive, the polyurethane resin may be a reaction product of polyester polyol and polyisocyanate. When using epoxy resins as gas barrier adhesives, a curing agent may be used in combination. Examples of curing agents include aliphatic amines, alicyclic amines, aromatic amines, and acid anhydrides. Among these, epoxy resins are particularly preferred as gas barrier adhesives. For example, commercially available gas barrier adhesives include the following: Polyurethane resins include combinations of PASLIM VM001 (manufactured by DIC Graphics Co., Ltd.) and PASLIM VM108CP (manufactured by DIC Graphics Co., Ltd.), PASLIM VM001 (manufactured by DIC Graphics Co., Ltd.) and PASLIM VM303CP (manufactured by DIC Graphics Co., Ltd.), and PASLIM NS-680A (manufactured by DIC Graphics Co., Ltd.) and PASLIM HA-680B (manufactured by DIC Graphics Co., Ltd.) (all are combinations of polyester polyol and polyisocyanate).Examples of epoxy resins include, for example, a combination of MAXIVE M-100 (manufactured by Mitsubishi Gas Chemical Company, Inc.) and MAXIVE C-93T (manufactured by Mitsubishi Gas Chemical Company, Inc.) (that is, a combination of an epoxy resin and an amine curing agent). From the viewpoint of gas barrier properties, a combination of MAXIVE M-100 and MAXIVE C-93T is particularly preferred.

[0047] By using a gas barrier adhesive, by laminating a gas barrier substrate film having an inorganic thin film layer and another film, the gas permeation path at the adhesion interface is blocked. As a result, high gas barrier properties can be maintained even after bending treatment without impairing the barrier performance of the inorganic thin film layer itself. In particular, the adhesive having gas barrier properties has little barrier deterioration after bending treatment. The reason for this is not clear, but it is considered that even if the gas barrier properties of the vapor deposition layer are impaired by bending, the gas barrier properties of the adhesive resin can minimize the damage to the gas barrier properties caused by bending.

[0048] Examples of the method for laminating the adhesive layer include, for example, direct gravure coating method, reverse gravure coating method, kiss coating method, die coating method, roll coating method, dip coating method, knife coating method, spray coating method, fountain coating method, and other methods. In order to exhibit sufficient adhesiveness, the coating amount after drying is 1 to 8 g / m 2 is preferred. More preferably 2 to 7 g / m 2 and even more preferably 3 to 6 g / m 2 is. If the coating amount is less than 1 g / m 2 , it becomes difficult to laminate over the entire surface, and there are portions where the plugging effect cannot be obtained, resulting in a decrease in gas barrier properties. Also, if it exceeds 8 g / m 2 , it takes time for the film to completely cure, unreacted substances tend to remain, and the cohesive force decreases, making it difficult to obtain the plugging effect and resulting in a decrease in gas barrier properties.

[0049] When forming the adhesive layer described above, it is preferable to heat-dry the adhesive after application, with a drying temperature of 50 to 120°C, more preferably 60 to 110°C, and even more preferably 70 to 100°C. If the drying temperature is below 50°C, the adhesive layer may not dry completely. On the other hand, if the drying temperature exceeds 120°C, the film may become too hot, causing it to become brittle or shrink, resulting in poor processability. In addition to drying, applying an additional heat treatment for 1 to 4 days at the lowest possible temperature range, specifically 40 to 60°C, is also more effective in promoting the formation of the adhesive layer.

[0050] [Coating Layer] A coating layer may be provided between at least one of the first and second base films and the inorganic thin film layer. By providing a coating layer, the exposure of oligomers and antiblocking agents from the resin can be suppressed. In particular, in the formation of the inorganic thin film layer, not only is adhesion improved, but the smoothing of the surface promotes the formation of the inorganic layer, and an effect of improving gas barrier properties can also be expected. In addition, by using a material that has a certain degree of gas barrier properties (referred to as gas barrier assisting properties) in the coating layer itself, the gas barrier performance of the film when the aforementioned gas barrier layer is laminated can also be greatly improved.

[0051] The coating layer preferably contains one or more selected from the group consisting of polyester resin and polyurethane resin. Examples of resin compositions used for the coating layer include polyurethane resin, polyester resin, acrylic resin, etc., to which curing agents such as epoxy curing agents, isocyanate curing agents, and melamine curing agents are added. Furthermore, crosslinking agents such as silicon-based crosslinking agents, carbodiimide compounds, and epoxy compounds may be included. Polyurethane resin is particularly preferred because, in addition to its barrier performance due to the high cohesiveness of the urethane bonds themselves, its polar groups interact with the gas barrier layer, and it also has flexibility due to the presence of amorphous portions, thus suppressing damage when a bending load is applied. Polyester resin is also preferred because similar effects can be expected. In this disclosure, it is particularly preferred to contain a polyurethane resin composed of polyester resin and isocyanate curing agent, and it is even more preferable to add a silicon-based crosslinking agent from the viewpoint of improving adhesion.

[0052] For the coating layer, it is more preferable to use a polyurethane resin that contains aromatic or aromatic aliphatic diisocyanate components as its main constituents, from the standpoint of gas barrier support. Among these, it is particularly preferable to use a polyurethane resin that contains metaxylylene diisocyanate components. By using the above resin, the cohesive force of the urethane bonds can be further enhanced by the stacking effect between aromatic rings, resulting in good gas barrier support.

[0053] It is preferable that the proportion of aromatic or aromatic aliphatic diisocyanate in the polyurethane resin used for the coating layer be in the range of 50 mol% or more (50 to 100 mol%) out of 100 mol% of the polyisocyanate component. The total proportion of aromatic or aromatic aliphatic diisocyanate is more preferably 60 to 100 mol%, even more preferably 70 to 100 mol%, and even more preferably 80 to 100 mol%. If the total proportion of aromatic or aromatic aliphatic diisocyanate is less than 50 mol%, good gas barrier assistance may not be obtained.

[0054] Various crosslinking agents may be added to the polyurethane resin used in the coating layer to improve the cohesive strength of the film and its resistance to moisture and heat adhesion. Examples of crosslinking agents include silicon-based crosslinking agents, carbodiimide compounds, and epoxy compounds. Among these, silicon-based crosslinking agents are particularly preferred because they can improve water-resistant adhesion to the inorganic thin film layer. Other crosslinking agents such as carbodiimide compounds and epoxy compounds may also be used in combination.

[0055] As silicon-based crosslinking agents, silane coupling agents are preferred from the viewpoint of crosslinking inorganic and organic substances. Suitable silane coupling agents include hydrolyzable alkoxysilane compounds, such as halogen-containing alkoxysilanes (chloroC2-4 alkyltriC1-4 alkoxysilanes such as 2-chloroethyltrimethoxysilane, 2-chloroethyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, etc.), and alkoxysilanes having epoxy groups [2-glycidyloxyethyltrimethoxysilane, 2-glycidyloxyethyltriethoxysilane, 3-glycidyloxypropyl Glycidyloxy C2-4 alkyl triC1-4 alkoxysilanes such as dimethoxysilane, 3-glycidyloxypropyltriethoxysilane, glycidyloxydiC2-4 alkyldiC1-4 alkoxysilanes such as 3-glycidyloxypropylmethyldimethoxysilane, 3-glycidyloxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltriethoxysilane, 3-(3,4-epoxycyclohexyl)propyl [e.g., (epoxycycloalkyl) C2-4 alkyltriC1-4 alkoxysilanes such as trimethoxysilane, amino group-containing alkoxysilanes (e.g., aminoC2-4 alkyltriC1-4 alkoxysilanes such as 2-aminoethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, aminoC2-4 alkyldiC1-4 alkoxysilanes such as 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, 2-[N-(2-aminoethyl)amine (2-aminoC2-4 alkyl)aminoC2-4 alkyltriC1-4 alkoxysilanes such as [N-(2-aminoethyl)amino]propyltrimethoxysilane, 3-[N-(2-aminoethyl)amino]propyltriethoxysilane, (aminoC2-4 alkyl)aminodiC2-4 alkyldiC1-4 alkoxysilanes such as 3-[N-(2-aminoethyl)amino]propylmethyldimethoxysilane, 3-[N-(2-aminoethyl)amino]propylmethyldiethoxysilane, etc.)Alkoxysilanes having a mercapto group (mercapto C2-4 alkyltriC1-4 alkoxysilanes such as 2-mercaptoethyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, etc., mercaptodiC2-4 alkyldiC1-4 alkoxysilanes such as 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, etc.), alkoxysilanes having a vinyl group (vinyltrimethoxysilanes such as vinyltriC1-4 alkoxysilanes such as vinyltriethoxysilane), ethylene Examples of silane coupling agents include alkoxysilanes having an unsaturated bonding group (such as 2-(meth)acryloxyethyltrimethoxysilane, 2-(meth)acryloxyethyltriethoxysilane, 3-(meth)acryloxypropyltrimethoxysilane, 3-(meth)acryloxypropyltriethoxysilane, etc., (meth)acryloxyC2-4 alkyltriC1-4 alkoxysilanes such as 3-(meth)acryloxypropylmethyldimethoxysilane, 3-(meth)acryloxypropylmethyldiethoxysilane, etc.). These silane coupling agents can be used alone or in combination of two or more. Among these silane coupling agents, those having an amino group are preferred, (2-aminoC2-4 alkyl)aminoC2-4 alkyltriC1-4 alkoxysilane is more preferred, and 3-[N-(2-aminoethyl)amino]propyltrimethoxysilane is even more preferred.

[0056] The silicon-based crosslinking agent is preferably added to the composition constituting the coating layer in an amount of 0.05 to 4.00% by mass, more preferably 0.10 to 3.50% by mass, and even more preferably 0.15 to 3.00% by mass. The addition of the silicon-based crosslinking agent promotes hardening of the film and improves its cohesive force, resulting in a film with excellent water-resistant adhesion, and is also expected to prevent the expression of oligomers. If the amount added exceeds 4.00% by mass, the film hardens and the cohesive force improves, but some unreacted areas may occur, potentially reducing the adhesion between layers. On the other hand, if the amount added is less than 0.05% by mass, sufficient cohesive force may not be obtained.

[0057] The polyester resin used for the coating layer is produced by polycondensation of a polycarboxylic acid component and a polyhydric alcohol component. While there are no particular restrictions on the molecular weight of the polyester resin as long as it provides sufficient film toughness, coating suitability, and solvent solubility as a coating material, the number average molecular weight is preferably 1,000 to 50,000, more preferably 1,500 to 30,000. There are also no particular restrictions on the functional groups at the polyester ends; it may have alcohol ends, carboxylic acid ends, or both. However, when using an isocyanate-based curing agent, it is necessary to use a polyester polyol primarily composed of alcohol ends.

[0058] The Tg of the polyester resin used in the coating layer is preferably 10°C or higher. If the temperature is lower than this, the resin becomes sticky after the coating operation, making blocking more likely and making the winding operation after coating difficult. If the Tg is below 10°C, it becomes difficult to prevent blocking even with the addition of a blocking agent or under high pressure conditions near the winding core. The Tg is more preferably 15°C or higher, even more preferably 20°C or higher, preferably 70°C or lower, and more preferably 60°C or lower.

[0059] The polyester resin used for the coating layer is a polycondensate of a polycarboxylic acid component and a polyhydric alcohol component. The polycarboxylic acid component of the polyester resin includes, for example, at least one ortho-oriented aromatic dicarboxylic acid or its anhydride. Ortho orientation improves solubility in solvents, enabling uniform coating of the substrate. A uniformly coated film has less variation in barrier performance, which in turn contributes to suppressing whitening caused by oligomers. Furthermore, ortho orientation results in a film with excellent flexibility and improved interfacial adhesion, which reduces damage to the substrate due to moist heat treatment and leads to oligomer suppression.

[0060] Aromatic polycarboxylic acids in which the carboxylic acid is substituted at the ortho position, or their anhydrides, include orthophthalic acid or its anhydride, naphthalene 2,3-dicarboxylic acid or its anhydride, naphthalene 1,2-dicarboxylic acid or its anhydride, anthraquinone 2,3-dicarboxylic acid or its anhydride, and 2,3-anthracenecarboxylic acid or its anhydride. These compounds may have substituents on any carbon atom of the aromatic ring. Furthermore, polyester polyols in which these polycarboxylic acids are present in a proportion of 70 to 100 mol% of the total polycarboxylic acid components are particularly preferred because they have a high barrier-improving effect and excellent solvent solubility, which is essential for coating materials.

[0061] In this disclosure, other polycarboxylic acid components may be copolymerized to the extent that they do not impair the effects of the invention. Specifically, as aliphatic polycarboxylic acids, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, etc.; as unsaturated bond-containing polycarboxylic acids, maleic anhydride, maleic acid, fumaric acid, etc.; as alicyclic polycarboxylic acids, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc.; as aromatic polycarboxylic acids, terephthalic acid, isophthalic acid, pyromellitic acid, trimellitic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, diphenic acid and its anhydrides, 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid and their anhydrides or ester-forming derivatives; and polybasic acids such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid and their ester-forming derivatives can be used alone or in mixtures of two or more. In particular, succinic acid, 1,3-cyclopentanedicarboxylic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, 1,8-naphthalic acid, and diphenic acid are preferred from the viewpoint of organic solvent solubility and gas barrier properties.

[0062] The polyhydric alcohol component of the polyester used in the coating layer is not particularly limited as long as it is possible to synthesize a polyester that exhibits gas barrier replenishment performance. However, it is preferable that the polyhydric alcohol component contains at least one selected from the group consisting of ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, cyclohexanedimethanol, and 1,3-bishydroxyethylbenzene. Among these, it is presumed that the fewer the number of carbon atoms between oxygen atoms, the less the molecular chain becomes excessively flexible and the less oxygen permeable it is, so it is most preferable to use ethylene glycol as the main component.

[0063] While it is preferable to use the aforementioned polyhydric alcohol components, other polyhydric alcohol components may also be copolymerized, provided that the effects of this disclosure are not impaired. Specifically, examples of diols include 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Examples of trihydric or higher alcohols include glycerol, trimethylolpropane, trimethylolethane, tris(2-hydroxyethyl) isocyanurate, 1,2,4-butanetriol, pentaerythritol, and dipentaerythulitol. In particular, among the trihydric alcohols, polyesters using glycerol and tris(2-hydroxyethyl) isocyanurate in combination are especially preferred because their branched structure results in a moderately high crosslink density, providing good organic solvent solubility and excellent barrier function.

[0064] Examples of catalysts used in the reaction to obtain the polyester resin of this disclosure include tin-based catalysts such as monobutyl tin oxide and dibutyl tin oxide, titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, and acid catalysts such as zirconia-based catalysts such as tetrabutyl zirconate. It is preferable to use a combination of the above-mentioned titanium-based catalysts, such as tetraisopropyl titanate and tetrabutyl titanate, which have high activity for esterification reactions, and the above-mentioned zirconia catalyst. The amount of catalyst is preferably 1 to 1000 ppm, more preferably 10 to 100 ppm, relative to the total mass of the reaction raw materials used. If the amount is less than 1 ppm, the catalytic effect is difficult to obtain, and if it exceeds 1000 ppm, problems may arise in that the urethane formation reaction is inhibited when an isocyanate curing agent is used.

[0065] In this disclosure, when a polyester resin is used as the main component of the coating agent constituting the coating layer, it is particularly preferable to use a polyisocyanate compound as the curing agent to form a polyurethane resin. In this case, since the coating layer becomes a cross-linked system, there are advantages such as improved heat resistance, abrasion resistance, and rigidity. On the other hand, there are also problems such as the inability to reuse the liquid after mixing with the curing agent and the necessity of a curing (aging) process after coating. As an advantage, for example, when used as a simple overcoat varnish, there is no risk of thickening of the coating liquid, the manufacturing control of the coating is easy, the coating liquid can be diluted and reused, and in addition, a curing process (so-called aging process) is unnecessary. In this case, the ends of the polyester used can be polyols, polycarboxylic acids, or mixtures of both without any problems. On the other hand, because the resin of the coating layer is linear, there may be cases where the heat resistance and abrasion resistance are insufficient, or problems may arise where it is difficult to use in boiling or retort packaging.

[0066] When a curing agent is used in the coating layer, isocyanate-based curing agents are preferred from the viewpoint of the heat resistance of the film, as it is a coating on a film. In this case, the resin component of the coating material must be polyester polyol. On the other hand, when an epoxy compound is used as the curing agent, it must be polyester polycarboxylic acid. In these cases, the coating layer becomes a cross-linked system, which has the advantage of improving heat resistance, abrasion resistance, and rigidity.

[0067] When a polyester has hydroxyl groups, polyisocyanate compounds react to form a urethane structure, increasing the polarity of the resin component and further enhancing the gas barrier function by agglomerating the polymer chains. Furthermore, when the resin of the coating material is a linear resin, crosslinking with a trivalent or higher polyisocyanate can impart heat resistance and abrasion resistance. The polyisocyanate compounds used in this disclosure may be diisocyanates, trivalent or higher polyisocyanates, low molecular weight compounds, or high molecular weight compounds, but those containing aromatic rings or aliphatic rings in part of the skeleton are preferable from the viewpoint of improving the gas barrier function. For example, examples of isocyanates having an aromatic ring include toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and naphthalene diisocyanate; examples of isocyanates having an aliphatic ring include hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, isophorone diisocyanate, norborn diisocyanate, or trimers of these isocyanate compounds; and end-isocyanate group-containing compounds obtained by reacting an excess amount of these isocyanate compounds with low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, and triethanolamine, or high molecular weight active hydrogen compounds such as various polyester polyols, polyether polyols, and polyamides. The polyisocyanate compound may be an adduct, allophanate, or biuret compound. In particular, it is preferable to use the trimethylolpropane adduct of metaxylylene diisocyanate as the polyisocyanate compound.

[0068] The amount of coating layer attached is 0.10 to 1.0 g / m 2 This is preferable. This allows for uniform control of the coating layer during the coating process, resulting in a film with fewer coating inconsistencies and defects. The amount of coating layer to be applied is preferably 0.15 g / m². 2 More preferably, 0.20 g / m 2More preferably 0.35 g / m 2 The above is true, and preferably 0.950 g / m². 2 More preferably, 0.90 g / m 2 More preferably, 0.85 g / m 2 The following applies: The amount of coating layer attached is 1.0 g / m². 2 Beyond this point, while gas barrier properties improve, the cohesive force within the coating layer becomes insufficient, and the uniformity of the coating layer decreases, resulting in unevenness and defects in the coating appearance. Furthermore, in terms of processability, the thicker film thickness can cause blocking, potentially increasing manufacturing costs. Moreover, there are concerns about adverse effects on the recyclability of the film, and the increased use of raw materials and solvents strengthens the environmental burden. On the other hand, a coating layer thickness of 0.10 g / m² 2 If the value is less than this, sufficient gas barrier properties and interlayer adhesion may not be obtained.

[0069] The method for forming the coating layer is not particularly limited, and conventionally known methods such as coating methods can be employed. Among coating methods, offline coating methods and inline coating methods are particularly suitable. For example, in the case of an inline coating method performed in the film manufacturing process, the drying and heat treatment conditions during coating depend on the coating thickness and the conditions of the equipment, but it is preferable to immediately send the coated material to a stretching process in a perpendicular direction and dry it in the preheating zone or stretching zone of the stretching process, and in such cases, it is usually preferable to set the temperature to about 50 to 250°C.

[0070] The coating method for the resin composition for the coating layer is not particularly limited as long as it is a method of coating the film surface to form a layer. For example, conventional coating methods such as gravure coating, reverse roll coating, wire bar coating, and die coating can be used.

[0071] When forming the coating layer, it is preferable to apply the coating layer resin composition and then heat-dry it, with the drying temperature preferably being 100 to 145°C, more preferably 110 to 140°C, and even more preferably 110 to 130°C. If the drying temperature is below 100°C, there is a risk of insufficient drying of the coating layer. On the other hand, if the drying temperature exceeds 145°C, the film may be overheated, causing it to become brittle or shrink, resulting in poor processability. In particular, it is especially preferable to first evaporate the solvent at a relatively low temperature of 80 to 110°C immediately after application, and then dry it at 120°C or higher, as this yields a uniform film. In addition to drying, applying an additional heat treatment in the lowest possible temperature range is also more effective in promoting the formation of the coating layer.

[0072] Examples of gas barrier laminate films according to this disclosure include a first base film / inorganic thin film layer / adhesive layer (preferably a gas barrier adhesive layer) / second base film, a first base film / coating layer / inorganic thin film layer / adhesive layer (preferably a gas barrier adhesive layer) / second base film, a first base film / inorganic thin film layer / adhesive layer / inorganic thin film layer / second base film, and a first base film / coating layer / inorganic thin film layer / adhesive layer / inorganic thin film layer / coating layer / second base film. In the gas barrier laminate film according to this disclosure, the inorganic thin film layer and the adhesive layer may be in direct or indirect contact, and direct contact is preferred. That is, it is preferable that the gas barrier laminate film according to this disclosure does not include a protective layer. It is also preferable that the gas barrier laminate film is heat-sealable, and may be heat-sealable when both the first and second base films are polyester films or polypropylene films.

[0073] The thickness of the gas barrier laminate film according to this disclosure is preferably 5 to 100 μm, more preferably 7 to 80 μm, and even more preferably 10 to 60 μm.

[0074] The water vapor transmission rate (W2) of the gas barrier laminate film (before bending) of this disclosure is 1.0 g / m². 2Preferably, it should be less than or equal to 0.01 g / m³ / day. 2 / day or more 0.8g / m 2 / day or less is more preferable, and 0.02 g / m 2 / day or more 0.7g / m 2 A value of 0.05 g / m² or less is even more preferable. 2 / day or more 0.6g / m 2 A value of less than or equal to / day is even more preferable. The water vapor transmission rate can be determined, for example, by the infrared sensor method (Appendix B) of JIS-K7129 under an atmosphere of 40°C and 90% humidity. Furthermore, the oxygen transmission rate (O2) of the gas barrier laminate film before bending treatment is 10 ml / m². 2 Preferably, the pressure should be less than or equal to / day / MPa, and less than or equal to 0.01 ml / m³. 2 / day / MPa or higher, 8 ml / m 2 / day / MPa or less is more preferable, and 0.02 ml / m³ 2 / day / MPa or more 7ml / m 2 A pressure of 0.1 ml / m³ is more preferable than / day / MPa. 2 / day / MPa or higher, 6 ml / m 2 A value of / day / MPa or less is even more preferable. Oxygen permeability can be determined, for example, by the electrolytic sensor method (Appendix A) B of JIS-K7126-2 under conditions of 23°C and 65% RH.

[0075] Because the gas barrier degradation after bending is minimal, when used as a food packaging material, damage during transportation and display can be minimized. The water vapor transmission rate (W3) of the gas barrier laminate film after bending is 3.0 g / m². 2 Preferably less than / day, and 0.01 g / m² 2 / day or more 2.8g / m 2 / day or less is more preferable, and 0.02 g / m 2 / day or more 2.5g / m 2 A value of 0.05 g / m² or less is even more preferable. 2 / day or more 2.0g / m 2 A value of 15 ml / m² or less is even more preferable. The oxygen permeability (O3) of the gas barrier laminate film after bending treatment is 15 ml / m².2 A pressure of 10 ml / m³ is preferred, preferably 1 / day / MPa or less. 2 / day / MPa or less is more preferable, and 0.01 ml / m³ 2 / day / MPa or higher, 8 ml / m 2 A pressure of 0.1 ml / m³ is more preferable than / day / MPa. 2 / day / MPa or higher, 6 ml / m 2 A pressure of / day / MPa or less is even more preferable. The bending treatment of the gas barrier laminate film can be obtained, for example, by using a Gelboflex tester at 25°C and performing a cycle of twisting a cylindrical sample 440°, pressing it straight, and returning it to its original position 50 times at a rate of 40 times per minute.

[0076] As a result of the inventors' investigations, it has become clear that the rate of improvement in water vapor permeability during lamination can be greatly improved by laminating a gas barrier substrate film having an inorganic thin film layer with a gas barrier adhesive, or by laminating two gas barrier substrate films having an inorganic thin film layer with an adhesive. By creating a configuration that makes full use of the sealing effect of the adhesive, the lamination process, which was conventionally just a bonding process, can now be improved to enhance gas barrier properties. This ingenuity makes it possible to improve gas barrier properties without laminating a coating layer or protective layer, and simplifies the processing process. When the portion formed from the substrate film and the inorganic thin film layer on its outermost surface is referred to as a gas barrier substrate film, the water vapor permeability of the gas barrier substrate film (W1) and the water vapor permeability of the gas barrier laminate film (W2) satisfy the following formula 1, and formula 1 serves as an indicator of the rate of improvement in water vapor permeability after processing. The value represented by Formula 1 is preferably 60% to 99%, more preferably 61% to 97%, even more preferably 65% ​​to 95%, and even more preferably 70% to 90%. Satisfying this range eliminates the need for lamination of coating layers and protective layers that were conventionally provided to impart gas barrier properties, thus eliminating these processing steps and offering advantages in terms of manufacturing costs. Formula 1: 100 - {(W2 / W1) × 100} ≥ 60 W1: Water vapor transmission rate of gas barrier substrate film (before lamination) W2: Water vapor transmission rate of gas barrier laminate film (after lamination) The water vapor transmission rates of W1 and W2 can be determined, as described later, for example, by the infrared sensor method (Appendix B) of JIS-K7129 under conditions of 40°C and 90% humidity.

[0077] It is preferable that the oxygen permeability (O1) of the gas barrier substrate film and the oxygen permeability (O2) of the gas barrier laminate film satisfy the following formula 2, where formula 2 is an indicator of the improvement rate of oxygen permeability after processing. The value represented by formula 2 is preferably 60% to 99%, more preferably 70% to 98%, even more preferably 80% to 97%, even more preferably 87% to 96%, and particularly preferably 90% to 96%. Formula 2: 100 - {(O2 / O1) × 100} ≥ 60 O1: Oxygen permeability of the gas barrier substrate film (before lamination) O2: Oxygen permeability of the gas barrier laminate film (after lamination) The oxygen permeability of O1 and O2 can be determined, for example, by the electrolytic sensor method (Appendix A) B of JIS-K7126-2 in an atmosphere of 23°C and 65% humidity, as described later.

[0078] Furthermore, by using a heat-sealable film for either the first or second base film, a laminate film with sealing functionality can be created, and a sealable laminate film with gas barrier properties can be produced in a single lamination process.

[0079] In particular, by making both the first and second base films polyester-based or polyolefin-based, the proportion of polyester or polyolefin components in the laminate film can be increased, resulting in a packaging bag suitable for material recycling. It is preferable to use polypropylene as the polyolefin. Polypropylene may be a homopolymer, a random copolymer with other α-olefins, or a block copolymer. The total mass of the polyester or polyolefin components in the laminate film is preferably 90% by mass or more, and more preferably 95% by mass or more, based on the total amount of the gas barrier laminate film. Alternatively, the total thickness of the polyester or polyolefin layer in the laminate film is preferably 90% or more, and more preferably 95% or more, based on the total thickness of the gas barrier laminate film. When these conditions are met, a recycled resin of high quality in terms of color and moldability can be obtained.

[0080] The gas barrier laminate film according to this disclosure can be suitably used as a packaging material for various items such as food, pharmaceuticals, daily necessities, and industrial products. This disclosure also includes food packaging materials using the gas barrier laminate film. The gas barrier laminate film according to this disclosure can be suitably used as a package if it is heat-sealable. The gas barrier laminate film according to this disclosure can be made into a bag on its own, or it may be laminated with other materials. Examples of other materials include, but are not limited to, unoriented films containing polyethylene terephthalate as a component, unoriented, uniaxially oriented, or biaxially oriented films containing other amorphous polyesters as a component, unoriented, uniaxially oriented, or biaxially oriented films containing nylon as a component, and unoriented, uniaxially oriented, or biaxially oriented films containing polypropylene as a component. The method of using the gas barrier laminate film in a package is not particularly limited, and conventionally known manufacturing methods such as coating, lamination, and heat sealing can be employed.

[0081] This application claims the benefit of priority based on Japanese Patent Application No. 2024-196782, filed on November 11, 2024. The entire specification of Japanese Patent Application No. 2024-196782, filed on November 11, 2024, is incorporated herein by reference.

[0082] Next, the present invention will be described in detail using examples and comparative examples, but this disclosure is not limited to the following examples. Unless otherwise specified, "%" means "mass percent" and "parts" means "parts by mass".

[0083] The evaluation methods and physical property measurement methods used in each example and comparative example are as follows.

[0084] (1) Preparation of Gas Barrier Laminate Film Bending Treatment Samples Gas barrier laminate film bending treatment samples were prepared using a Gelboflex tester (MIL-B131H) manufactured by Rigaku Kogyo Co., Ltd. by the following method. The gas barrier laminate films obtained in the examples and comparative examples were cut to 12 inches x 8 inches to form a cylindrical shape with a diameter of 3.5 inches. One end of the cylindrical film was fixed to the fixed head side of the Gelboflex tester and the other end to the movable head side, with an initial gripping distance of 7 inches. Bending fatigue was performed 50 times at a speed of 40 times / minute, with a twist of 440 degrees applied in the first 3.5 inches of the stroke, followed by a linear horizontal movement for the remaining 2.5 inches to complete the entire stroke. The measurements were taken in an environment of 25°C.

[0085] (2) Method for Evaluating Water Vapor Transmission Rate (WTR) The water vapor transmission rate was measured for the gas barrier substrate films obtained in the examples and comparative examples using a water vapor transmission rate measuring device ("PERMATRAN-W 3 / 34G" manufactured by MOCON Corporation) in accordance with the infrared sensor method (Appendix B) of JIS-K7129, under an atmosphere of 40°C and 90% humidity. The water vapor transmission rate was measured in the direction in which water vapor permeates from the substrate film side without the inorganic thin film layer to the inorganic thin film layer side. The water vapor transmission rate was also measured for the gas barrier laminate films obtained in the examples and comparative examples, and for the gas barrier laminate films prepared by bending in (1) above, in the same manner as above, and the water vapor transmission rate (W2) and water vapor transmission rate (W3) were obtained. The water vapor transmission rate (W1) was measured using the gas barrier substrate film. The improvement rate (%) of water vapor permeability after processing, expressed in the following formula 1, was calculated from the water vapor permeability (W1) and water vapor permeability (W2). Formula 1: 100 - {(W2 / W1) × 100} ≥ 60 W1: Water vapor permeability of gas barrier substrate film (before lamination) W2: Water vapor permeability of gas barrier laminate film (after lamination)

[0086] (3) Method for Evaluating Oxygen Permeability (OTR) The oxygen permeability of the gas barrier substrate film obtained as described in the Examples and Comparative Examples was measured using an oxygen permeability measuring device (MOCON "OX-TRAN 2 / 20") in accordance with the electrolytic sensor method (Appendix A) B of JIS-K7126-2, under an atmosphere of 23°C and 65% RH. The oxygen permeability was measured in the direction of permeation from the substrate film side without the inorganic thin film layer to the inorganic thin film layer side. The oxygen permeability was also measured in the same manner as above for the gas barrier laminate film obtained in the Examples and Comparative Examples and the gas barrier laminate film prepared by bending treatment as described in (1) above, and the oxygen permeability (O2) and oxygen permeability (O3) were obtained. The oxygen permeability (O1) was measured using the gas barrier substrate film. The improvement rate (%) of oxygen permeability after processing, expressed in the following formula 2, was calculated from the oxygen permeability (O1) and oxygen permeability (O2). Formula 2: 100 - {(O2 / O1) × 100} ≥ 60 O1: Oxygen permeability of gas barrier substrate film (before lamination) O2: Oxygen permeability of gas barrier laminate film (after lamination)

[0087] (4) Method for evaluating sealing performance Samples were prepared by heat sealing the gas barrier laminate films obtained in the examples and comparative examples with the films facing each other and overlapping, under the conditions of a heat sealer temperature of 170°C, a sealing pressure of 10 MPa, and a sealing time of 1 second. The obtained samples were visually inspected and sensory evaluation was performed to determine whether a seal was achieved. If a seal was achieved, the evaluation was marked with a circle (○).

[0088] (5) Evaluation criteria for monomaterialization: For gas barrier laminate films produced in the examples with a monomaterial ratio of less than or equal to the given monomaterial ratio, the monomaterial ratio was calculated as the ratio of the thickness of the polyester-based material or polyolefin-based material to the total thickness of each film and adhesive.

[0089] <Example 1> A biaxially oriented copolymer polyester film with heat-sealing properties (Toyobo Co., Ltd.'s "Oriester® SS DE046, 30 μm thick," with a heat-sealing layer made of polyester on one side) was used as the first base film, and a composite oxide layer of silicon dioxide and aluminum oxide was formed on the base film by electron beam deposition. Particulate SiO2 (99.9% purity) and A12O3 (99.9% purity) of about 3 mm to 5 mm were used as the deposition source. The thickness of the inorganic thin film layer (SiO2 / A12O3 composite oxide layer) at this time was 13 nm, and the composition was SiO2 / A12O3 (mass ratio) = 60 / 40. A gas barrier base film was obtained in this way. Furthermore, a gas barrier laminate film for evaluation was obtained by dry lamination using a dry laminating adhesive to bond the second base film (biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd.'s "Toyobo Ester® Film E5100, 12 μm thick")) to the first base film, drying at 70°C, and then aging at 40°C for 4 days. The thickness of the adhesive layer after drying was approximately 3 μm. The following adhesive was used: a gas barrier adhesive (Mitsubishi Gas Chemical Company's Maxive® main component "M-100" (epoxy resin) and curing agent "C-93T" (amine curing agent) blended in a ratio of 16.2:5 (mass ratio)).

[0090] <Example 2> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the first base film was a biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd.'s "Toyobo Ester® Film E5100, 12 μm thick") and the second base film was a biaxially oriented copolymer polyester film (Toyobo Co., Ltd.'s "DE046, 30 μm thick").

[0091] <Example 3> A gas barrier laminate film was obtained in the same manner as in Example 2, except that the gas barrier substrate film was obtained by the following method. A biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd.'s "Toyobo Ester® Film E5100, 12 μm thick") was used as the first substrate film, and aluminum oxide was deposited onto the substrate film. The method for depositing aluminum oxide onto the substrate film layer was to set the film on the unwinding side of a continuous vacuum deposition machine and run it through a cooling metal drum to wind up the film. At this time, the continuous vacuum deposition machine was set to 10 -4 The pressure was reduced to below Torr, and 99.99% pure metallic aluminum was loaded into an alumina crucible from the bottom of the cooling drum. The metallic aluminum was heated and evaporated, and oxygen was supplied into the vapor to cause an oxidation reaction, which allowed it to adhere and deposit onto the film, forming a 10 nm thick aluminum oxide film.

[0092] <Example 4> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the first base film was a biaxially oriented polyethylene terephthalate film (Toyobo Co., Ltd.'s "Toyobo Ester® Film E5100, 12 μm thick").

[0093] <Example 5> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the second base film was the gas barrier base film 1 obtained in Example 2, and the adhesive was a polyurethane two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0094] <Example 6> A gas barrier laminate film was obtained in the same manner as in Example 2, except that the second base film was the gas barrier base film 1 obtained in Example 2, and the adhesive was a polyurethane two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0095] <Example 7> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the first base film was a biaxially oriented polypropylene film (OPP) obtained by the following method, and the second base film was a biaxially oriented polypropylene film (OPP) obtained by the following method.

[0096] Method for producing biaxially oriented polypropylene film (OPP): The base layer (A) used was a mixture of 30% by mass of a propylene homopolymer (PP "FS2012" manufactured by Sumitomo Chemical Co., Ltd., with Mn = 81,000, Mw = 320,000, MFR = 2.2 g / 10 min, and mesopentad fraction [mmmm] = 99.2%; and 70% by mass of a propylene homopolymer (PP "FLX80E4" manufactured by Sumitomo Chemical Co., Ltd., with Mn = 65,000, Mw = 240,000, MFR = 7.5 g / 10 min, and mesopentad fraction [mmmm] = 98.9%; and 0% by mass of a propylene homopolymer (PP "FLX80E4" manufactured by Sumitomo Chemical Co., Ltd., with Mn = 65,000, Mw = 240,000, MFR = 7.5 g / 10 min, and mesopentad fraction [mmmm] = 98.9%. Furthermore, the surface layer (B) used a mixture consisting of 24.8% by mass of a propylene polymer (Novatec® PP "FL4" manufactured by Nippon Polypropylene Co., Ltd.) with Mn = 55,000, Mw = 300,000, MFR = 5.6 g / 10 min, and mesopentad fraction [mmmm] = 98.4%, 72.2% by mass of a propylene polymer (Prime Polypropylene "F-300SP" manufactured by Prime Polymer Co., Ltd.) with Mn = 59,000, Mw = 310,000, MFR = 5.3 g / 10 min, and mesopentad fraction [mmmm] = 93.8%, and 3.0% by mass of masterbatch A as shown in Table 1. The base layer (A) was produced using a 45 mm extruder, the surface layer (B) using a 25 mm extruder, and the second surface layer (B) using a 20 mm extruder. The raw resin was melted at 250°C in each case, and co-extruded into a sheet from a T-die. After cooling and solidifying so that the surface layer (B) was in contact with a cooling roll at 40°C, the film was stretched 4.5 times in the longitudinal direction (MD) at 125°C. Next, in a tenter, both ends in the film width direction (TD) were clamped with clips, preheated to 174°C, and then stretched 8.2 times in the width direction (TD) at 158°C. The film was then heat-set at 175°C while relaxing by 6.7% in the width direction (TD). The film-forming conditions at this time were designated as film-forming conditions a. In this way, a biaxially oriented polypropylene film with the structure of surface layer (B) / base layer (A) / second surface layer (B) was obtained. The surface of the biaxially oriented polypropylene film's surface layer (B) was subjected to corona treatment using a corona treatment machine manufactured by Softal Corona and Plasma GmbH at an applied current of 0.75 A, and then wound up with a winder.The thickness of the obtained film was 20 μm (the thickness of the surface layer (B) / substrate layer (A) / second surface layer (B) was 1.0 μm / 18.0 μm / 1.0 μm).

[0097]

[0098] Method for producing a gas barrier substrate film Preparation of coating liquid 1 used for the coating layer [Polyester resin (a)] Polyester polyol (DIC Corporation's "DF-COAT GEC-004C": solid content 30%) was used as the polyester component.

[0099] [Polyisocyanate crosslinking agent (b)] As the polyisocyanate component, a trimethylolpropane adduct of metaxylylene diisocyanate ("Takenate D-110N" manufactured by Mitsui Chemicals, Inc.: solid content 75%) was used.

[0100] [Silane Coupling Agent (c)] N-2-(aminoethyl)-3-aminopropyltrimethoxysilane (KBM-603, manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the silane coupling agent. A solution of silane coupling agent (c) dissolved in acetone (15% by mass) and isocyanate (b) were mixed in the following ratios and stirred for 10 minutes using a magnetic stirrer. The resulting mixture was diluted with methyl ethyl ketone and 1-methoxy-2-propanol (hereinafter PGM), and polyester resin (a) was added to obtain the target coating solution 1. The mixing ratio is as follows: Polyester resin (a) 10.62% by mass Isocyanate (b) 4.07% by mass Silane coupling agent (c) *Acetone diluted solution 1.73% by mass Methyl ethyl ketone 69.55% by mass PGM 14.03% by mass

[0101] (1) Using coating liquid 1 for coating the film, the coating liquid was applied to the corona-treated surface of the biaxially oriented polypropylene film by gravure roll coating, pre-dried at 95°C for 4 seconds, and then fully dried at 115°C for 4 seconds to obtain a coating layer. The amount of coating layer attached at this time was 0.40 g / m². 2Subsequently, a post-heat treatment was performed at 40°C for 4 days (96 hours) to obtain a biaxially oriented polypropylene film with a coating layer.

[0102] (2) Formation of an inorganic thin film layer Next, a composite inorganic oxide layer of silicon dioxide and aluminum oxide was formed on the coating layer surface of the film obtained in (1) above by electron beam deposition as an inorganic thin film layer. Particulate SiO2 (purity 99.9%) and A12O3 (purity 99.9%) of about 3 mm to 5 mm were used as the deposition source. The composition of the composite oxide layer was SiO2 / A12O3 (mass ratio) = 70 / 30. The thickness of the inorganic thin film layer (SiO2 / A12O3 composite oxide layer) was 13 nm. In this way, a gas barrier substrate film was obtained.

[0103] <Example 8> A gas barrier laminate film was obtained in the same manner as in Example 7, except that the second base film was an unoriented polypropylene film (Toyobo Co., Ltd.'s "Pyrene® Film - CT P1153, 50 μm thick").

[0104] <Comparative Example 1> A gas barrier substrate film of the first substrate film 1 obtained in Example 1 was obtained as the first substrate film, but no further lamination was performed.

[0105] <Comparative Example 2> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the adhesive used was a polyurethane-based two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0106] <Comparative Example 3> A gas barrier laminate film was obtained in the same manner as in Example 2, except that the adhesive used was a polyurethane-based two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0107] <Comparative Example 4> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the gas barrier substrate film was polyethylene terephthalate film (Toyobo Co., Ltd.'s "Toyobo Ester® Film E5100, 12 μm thick").

[0108] <Comparative Example 5> A gas barrier laminate film was obtained in the same manner as in Example 1, except that the gas barrier substrate film was obtained by the following method and the adhesive was a polyurethane two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0109] <Preparation of each material used for the coating or protective layer formed on the gas barrier substrate film> [Oxazoline group-containing resin (A)] A commercially available water-soluble oxazoline group-containing acrylate ("Epocross® WS-300" manufactured by Nippon Shokubai Co., Ltd.; solid content 10%) was prepared as the oxazoline group-containing resin. The amount of oxazoline groups in this resin was 7.7 mmol / g.

[0110] [Acrylic resin (B)] As the acrylic resin, a 25% by mass emulsion of a commercially available acrylic acid ester copolymer ("Movinyl (registered trademark) 7980" manufactured by Nichigo Movinyl Co., Ltd.) was prepared. The acid value (theoretical value) of this acrylic resin (B) was 4 mg KOH / g.

[0111] [Urethane Resin (C)] As the urethane resin, a commercially available polyester urethane resin dispersion (Mitsui Chemicals, Ltd. "Takelac® W605"; solid content 30%) was prepared. The acid value of this urethane resin was 25 mg KOH / g, and the glass transition temperature (Tg) measured by DSC was 100°C. 1 The proportion of aromatic or aromatic aliphatic diisocyanates to the total polyisocyanate components, as measured by 1H-NMR, was 55 mol%.

[0112] [Urethane Resin (D)] As the urethane resin, a commercially available metaxylylene group-containing urethane resin dispersion (Mitsui Chemicals, Ltd. "Takelac® WPB341"; solid content 30%) was prepared. The acid value of this urethane resin was 25 mg KOH / g, and the glass transition temperature (Tg) measured by DSC was 130°C. 1 The proportion of aromatic or aromatic aliphatic diisocyanates to the total polyisocyanate components, as measured by 1H-NMR, was 85 mol%.

[0113] Method for producing a gas barrier substrate film (1) Preparation of coating solution 1 to be used for the coating layer The following materials were mixed in the following proportions to prepare a coating solution (resin composition for the coating layer). The mass ratio of the oxazoline group-containing resin (A), acrylic resin (B), and urethane resin (C) in the obtained coating solution, on a solid content basis, was 50 / 30 / 20. Water 54.40% Isopropanol 25.00% Oxazoline group-containing resin (A) 15.00% Acrylic resin (B) 3.60% Urethane resin (C) 2.00%

[0114] (2) Preparation of coating liquid 2 to be used for coating the protective layer The following coating agents were mixed to prepare coating liquid 2: Water 60.00% Isopropanol 30.00% Urethane resin (D) 10.00%

[0115] (3) Manufacturing of polyethylene terephthalate substrate film (PET) and coating with coating liquid 1 (lamination of coating layer) A polyethylene terephthalate resin with an intrinsic viscosity of 0.62 dl / g (30°C, phenol / tetrachloroethane = 60 / 40) was precrystallized, then fully dried, extruded at 280°C using an extruder with a T-die, and rapidly cooled and solidified on a drum with a surface temperature of 40°C to obtain an amorphous sheet. Next, the obtained sheet was stretched 4.0 times in the longitudinal direction at 100°C between a heating roll and a cooling roll. Then, the above coating liquid 1 was coated on one side of the obtained uniaxially oriented film by the fountain bar coating method. It was guided to a tenter while drying, preheated at 100°C, stretched 4.0 times in the width direction at 120°C, and heat treated at 225°C while allowing 6% widthwise relaxation to be performed to obtain a biaxially oriented polyethylene terephthalate film with a thickness of 12 μm at a density of 0.020 g / m². 2 A film with a coating layer formed on it was obtained.

[0116] (4) Formation of an inorganic thin film layer Next, a composite inorganic oxide layer of silicon dioxide and aluminum oxide was formed on the coating layer surface of the film obtained in (3) above by electron beam deposition as an inorganic thin film layer. Particulate SiO2 (purity 99.9%) and A12O3 (purity 99.9%) of about 3 mm to 5 mm were used as the deposition source. The composition of the composite oxide layer was SiO2 / A12O3 (mass ratio) = 60 / 40. The thickness of the inorganic thin film layer (SiO2 / A12O3 composite oxide layer) was 13 nm.

[0117] (5) Coating of coating solution 2 onto the vapor-deposited film (lamination of protective layer) The coating solution 2 was applied to the inorganic thin film layer of the film obtained in (4) by the wire bar coating method, and dried at 200°C for 15 seconds to obtain a protective layer. The amount of coating after drying was 0.190 g / m 2 It was (Dry). In this way, a gas barrier substrate film was obtained.

[0118] <Comparative Example 6> A gas barrier laminate film was obtained in the same manner as in Example 7, except that the adhesive was a polyurethane-based two-component curing adhesive (a mixture of Mitsui Chemicals' "Takelac® A525S" (polyester polyol) and "Takenate® A50" (polyisocyanate) in a ratio of 13.5:1 (mass ratio)).

[0119] The water vapor and oxygen permeability of the gas barrier substrate film, gas barrier laminate film, and gas barrier laminate film after bending treatment were measured. The presence or absence of sealing properties was also evaluated. The results are shown in Tables 2A and 2B.

[0120]

[0121]

[0122] Table 2A shows that the gas barrier laminate films obtained in Examples 1 to 8 showed a post-processing improvement rate of 60% or more in water vapor permeability. Examples 1 to 4, 7, and 8 showed that the improvement tendency increased when the inorganic thin film layer came into contact with the gas barrier adhesive, and Examples 5 to 6 showed that the improvement tendency increased when the inorganic thin film layer had multiple interfaces with the adhesive.

[0123] A comparison of Examples 1 to 4 with Comparative Example 5 shows that in Examples 1 to 4, the inorganic thin film layer, when in contact with the gas barrier adhesive, has a post-bending water vapor permeability comparable to that of Comparative Example 5, which has a coating layer and a protective layer.

[0124] Furthermore, Examples 1, 2, 3, 5, and 8 use a heat-sealable base film, resulting in a gas barrier laminate film with excellent sealing properties. Since subsequent bonding with a sealant film is unnecessary, the processing time can be reduced, making it highly useful.

[0125] This disclosure provides a gas barrier laminate film in which the gas barrier properties of the inorganic thin film layer of a gas barrier substrate film are improved by laminating in a way that maximizes the sealing effect of the adhesive, and the processing steps are simplified, making it easy to handle in subsequent processing.

Claims

1. A gas barrier laminate film comprising first and second base films and an adhesive layer interposed between them, wherein at least one of the first and second base films has an inorganic thin film layer formed on its outermost surface, and the inorganic thin film layer and the adhesive layer are in contact, and the portion formed from the base film and the inorganic thin film layer on its outermost surface is referred to as the gas barrier base film, characterized in that the water vapor permeability (W1) of the gas barrier base film and the water vapor permeability (W2) of the gas barrier laminate film satisfy the following formula 1. Formula 1: 100 - {(W2 / W1) × 100} ≥ 60 2. The gas barrier laminate film according to claim 1, wherein the inorganic thin film layer comprises one or more selected from the group consisting of aluminum, aluminum oxide, silicon oxide, and a composite oxide of silicon oxide and aluminum oxide.

3. The gas barrier laminate film according to claim 1, wherein the adhesive comprises one or more selected from the group consisting of polyurethane resins, polyester resins, epoxy resins, poly(meth)acrylic resins, polyol resins, and copolymer resins thereof.

4. A gas barrier laminate film according to claim 1, wherein a coating layer is provided between at least one of the first and second base films and the inorganic thin film layer, and the coating layer comprises one or more selected from the group consisting of polyester resin and polyurethane resin.

5. The water vapor transmission rate (W2) of the gas barrier laminate film is 1.0 g / m². 2 A gas barrier laminate film according to claim 1, wherein the number of days is less than or equal to / day.

6. The water vapor transmission rate (W3) of the gas barrier laminate film after bending treatment is 3.0 g / m². 2 A gas barrier laminate film according to claim 1, wherein the number of days is less than or equal to / day.

7. The gas barrier laminate film according to claim 1, wherein the oxygen permeability (O1) of the gas barrier substrate film and the oxygen permeability (O2) of the gas barrier laminate film satisfy the following formula 2: Formula 2: 100 - {(O2 / O1) × 100} ≥ 60 8. The oxygen permeability (O3) of the gas barrier laminate film after bending is 10 ml / m². 2 A gas barrier laminate film according to claim 1, wherein the pressure is less than or equal to / day / MPa.

9. The gas barrier laminate film according to claim 1, wherein both the first and second base films are polyester films.

10. The gas barrier laminate film according to claim 1, wherein the gas barrier laminate film is heat-sealable.

11. The gas barrier laminate film according to claim 1, wherein both the first and second base films are polypropylene films.

12. The gas barrier laminate film according to claim 11, wherein at least one of the first and second base films has a base layer and a surface layer, and the base layer and the surface layer comprise one or both of a polypropylene homopolymer and a polypropylene copolymer.

13. A food packaging material using a gas barrier laminate film according to any one of claims 1 to 12.

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