Gas barrier film and method for manufacturing the same

Abstract

A gas barrier film having: a resin base material, an oxygen barrier coating film on at least one face of the resin base material, and a base layer and / or an inorganic oxide layer between the resin base material and the oxygen barrier coating film, the black area ratio of one face measured by the following measurement method being 0.15% or less. <Measurement Method> An arbitrary area of 1281 μm square of one face of the resin base material is photographed using an optical microscope, a photographed image of 1024 x 1024 pixels is obtained, the photographed image is converted into a monochrome image of 256 grays using image analysis software, the value obtained by subtracting 30 from the most frequent value of the brightness of the monochrome image is used as a threshold value, the values less than the threshold value are set to black and the values of 2 or more are set to white to value the brightness, the number of black pixels in the area of 1281 μm square is counted, and the proportion of the total area of the black regions above is taken as the black area ratio. 2 the black area ratio of one face measured by the following measurement method being 0.15% or less. <Measurement Method> An arbitrary area of 1281 μm square of one face of the resin base material is photographed using an optical microscope, a photographed image of 1024 x 1024 pixels is obtained, the photographed image is converted into a monochrome image of 256 grays using image analysis software, the value obtained by subtracting 30 from the most frequent value of the brightness of the monochrome image is used as a threshold value, the values less than the threshold value are set to black and the values of 2 or more are set to white to value the brightness, the number of black pixels in the area of 1281 μm square is counted, and the proportion of the total area of the black regions above is taken as the black area ratio. 2 the black area ratio of one face measured by the following measurement method being 0.15% or less. <Measurement Method> An arbitrary area of 1281 μm square of one face of the resin base material is photographed using an optical microscope, a photographed image of 1024 x

Description

Technical Field

[0001] This disclosure relates to a gas barrier membrane and a method for manufacturing the same. Background Technology

[0002] In order to prevent the contents from deteriorating and spoiling, and to maintain their function and properties, packaging materials used for food, medicine, and other products need to have the property of preventing gases (water vapor, oxygen, etc.) that would cause the contents to deteriorate from entering; that is, gas barrier properties. Therefore, these packaging materials use gas barrier membrane materials (gas barrier films).

[0003] As a gas barrier film, it is known to apply a gas barrier layer made of a gas barrier material to the surface of a resin substrate. As a gas barrier layer, metal foil or metal vapor-deposited film, or a coating formed by a wet coating method are known. As a coating, i.e., a film exhibiting oxygen barrier properties, known examples include: resin films formed from a coating agent containing a water-soluble polymer, polyvinylidene chloride, or similar resin; and inorganic layered mineral composite resin films formed from a coating agent containing a water-soluble polymer and inorganic layered minerals (Patent Document 1). Furthermore, as a gas barrier layer, the following schemes have been proposed: a gas barrier layer formed by sequentially layering a vapor-deposited thin film layer composed of inorganic oxides and a gas barrier composite coating containing a water-based polymer, an inorganic layered compound, and a metal alkoxide (Patent Document 2); and a gas barrier layer containing a multivalent metal salt of a carboxylic acid, which is a reaction product of a carboxyl group of a polycarboxylic acid polymer and a multivalent metal compound (Patent Document 3).

[0004] To improve gas barrier properties, for example, Patent Document 4 proposes a gas barrier film in which a coating is formed on at least one surface of a substrate, the surface roughness parameter Rt / Ra of the coating surface being 20 or less. Here, Rt is the distance between the largest peak and the deepest valley of the surface roughness curve. Ra is the centerline average roughness. The gas barrier film according to Patent Document 4 aims to improve gas barrier properties.

[0005] Existing technical documents

[0006] Patent documents

[0007] [Patent Document 1] Japanese Patent No. 6191221

[0008] [Patent Document 2] Japanese Patent Application Publication No. 2000-254994

[0009] [Patent Document 3] Japanese Patent No. 4373797

[0010] [Patent Document 4] Japanese Patent Application Publication No. 9-150484 Summary of the Invention

[0011] [The problem the invention aims to solve]

[0012] However, the oxygen barrier properties of gas barrier films obtained by applying coatings to the surface of resin substrates using wet coating, vapor deposition, or sputtering methods can sometimes be unstable due to variations in production batches. Specifically, the oxygen barrier properties of the gas barrier film are worse than the original oxygen barrier properties, which are assumed based on the materials constituting the coating and its thickness. This problem tends to occur particularly easily when the coating thickness becomes thinner. Therefore, the thickness of the gas barrier layer must be increased to a thickness greater than the required thickness, resulting in poor productivity and excessively high material costs.

[0013] In addition, printing is sometimes performed on the surface of the gas barrier film. Therefore, it is required that the gas barrier film be easy to print on its surface (printability).

[0014] This disclosure was made in view of the above circumstances, and its object is to provide a gas barrier film and a method thereof that can fully exhibit the original oxygen barrier properties and exhibit excellent gas barrier properties and good printability even when the thickness of the coating used to impart oxygen barrier properties is reduced.

[0015] [Solutions for solving the problem]

[0016] The gas barrier film disclosed herein comprises: a resin substrate, an oxygen barrier coating disposed on at least one side of the resin substrate, and either or both of a base layer and an inorganic oxide layer disposed between the resin substrate and the oxygen barrier coating, wherein the black area fraction of one side of the resin substrate, as measured by the following measurement method, is 0.15% or less.

[0017] <Determination Method>

[0018] An arbitrary 1281 μm square region on one side of a resin substrate was photographed using an optical microscope, obtaining a 1024×1024 pixel image. Image analysis software was used to convert the image into a 256 grayscale monochrome image. The most frequent brightness value in the monochrome image was subtracted by 30, and the resulting value was used as a threshold. Values ​​below the threshold were set to black, and values ​​above the threshold were set to white to binarize the brightness. The size of the 1281 μm square region was defined as 100 μm. 2 The proportion of the total area of ​​the black regions mentioned above is called the black area ratio.

[0019] The method for manufacturing the gas barrier film disclosed herein includes: a step of measuring the black area ratio of the surface of a resin substrate raw material by the above-described measurement method, and preparing a resin substrate raw material with a black area ratio of 0.15% or less on at least one side as a resin substrate; and a step of coating an agent onto at least one side of the resin substrate to form at least an oxygen barrier coating.

[0020] The effects of the invention

[0021] According to the gas barrier film disclosed herein, even if the thickness of the oxygen barrier coating is reduced, the performance deviation between production batches is small, and the original oxygen barrier properties can be stably exhibited, thereby achieving excellent gas barrier properties and good printability. Attached Figure Description

[0022] [ Figure 1 ] Figure 1 This is a cross-sectional view of the gas barrier membrane of Embodiment 1.

[0023] [ Figure 2 ] Figure 2 This is an image obtained by taking a picture of one side of the resin substrate of Embodiment 1 using an optical microscope.

[0024] [ Figure 3 ] Figure 3 This is an example of a histogram used when calculating the black area ratio.

[0025] [ Figure 4 ] Figure 4 This is a cross-sectional view of the gas barrier membrane of Embodiment 2.

[0026] [ Figure 5 ] Figure 5 This is a schematic diagram illustrating a measuring device for determining the number of protrusions on the first surface of a resin substrate.

[0027] [ Figure 6 ] Figure 6 A schematic diagram illustrating the principle of detecting protrusions.

[0028] [ Figure 7 ] Figure 7 An image of the first side of the resin substrate used in the embodiment is shown, along with an analytical image of the protrusions detected in the image.

[0029] [ Figure 8 ] Figure 8 A cross-sectional electron microscope image taken using a focused ion / electron beam processing observation device to show coating defects generated in areas where AB agent is present in the resin substrate. Detailed Implementation

[0030] (Implementation Method 1)

[0031] To investigate the cause of the aforementioned problem, the inventors used an optical microscope or an electron microscope to observe in detail the surface and cross-section of the gas barrier film with poor oxygen barrier properties. In the areas where an anti-blocking agent (hereinafter also referred to as "AB agent") added to prevent adhesion of the resin substrate was present, cross-sectional electron microscopy was performed using a focused ion / electron beam processing observation device. The results confirmed that defects with a width of several μm were generated in the coating in areas where the AB agent was prominently protruding. It is believed that these defects become pathways for gas permeation, thus failing to adequately exhibit oxygen barrier properties.

[0032] The surface of the resin substrate contains protrusions of various sizes created by the AB agent. It is believed that the protrusion height and density of the AB agent vary depending on the production batch of the resin substrate. When a gas barrier film is applied to the surface of the resin substrate, defects occur in areas where the film does not form locally at the locations of large protrusions, thus making the oxygen barrier properties unstable.

[0033] Furthermore, by using a microscope to observe in detail the transfer defects (sometimes called leaks) of fine dots produced in the high-gloss printing area of ​​the gas barrier film, it was confirmed that the AB agent is prone to producing leaks in high-protruding positions.

[0034] Therefore, the inventors designed a method to accurately grasp the surface state of a resin substrate over a wide range that affects the oxygen barrier properties and printability of the gas barrier film in a short time. They discovered that binarizing the optical microscope image of the resin substrate surface to a depth of 100 μm... 2 When the total area ratio of the black areas (hereinafter referred to as the black area ratio) is less than 0.15%, the oxygen barrier performance is excellent and the printability on the gas barrier film is good, thus completing this disclosure.

[0035] Embodiments of the barrier membrane of this disclosure are shown and described.

[0036] Figure 1 This is a schematic cross-sectional view of the gas barrier membrane 1 according to Embodiment 1. For ease of explanation, Figure 1 The dimensions shown in the image differ from the actual dimensions.

[0037] The gas barrier membrane 1 comprises: a resin substrate 10, a base layer 30, an inorganic oxide layer 40, and an oxygen barrier coating 20. It should be noted that either the base layer 30 or the inorganic oxide layer 40 may be absent.

[0038] A substrate 30 is laminated in contact with one surface 12 of the resin substrate 10, and an inorganic oxide layer 40 is laminated on the opposite surface of the substrate 30 to the surface in contact with the resin substrate 10. The inorganic oxide layer 40 is laminated in contact with the substrate 30, and an oxygen barrier coating 20 is in contact with and located on the opposite surface of the inorganic oxide layer 40 to the surface in contact with the substrate 30. It should be noted that, without the substrate 30, the inorganic oxide layer 40 is laminated on one surface 12 of the resin substrate 10. Furthermore, without the inorganic oxide layer 40, the oxygen barrier coating 20 is laminated on the substrate 30.

[0039] <Resin substrate>

[0040] The resin substrate 10 contains resin. Examples of resins constituting the resin substrate 10 include: olefin resins such as polyethylene, polypropylene, olefin polymers with 2 to 10 carbon atoms, and propylene-ethylene copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyamide resins such as aliphatic polyamides such as nylon 6 and nylon 66, and aromatic polyamides such as poly(m-phenylene adipamide); vinyl resins such as polystyrene, polyvinyl acetate, ethylene-vinyl acetate copolymers, polyvinyl alcohol, and ethylene-vinyl alcohol copolymers; acrylic resins such as homopolymers or copolymers of (meth)acrylic monomers such as polymethyl methacrylate and polyacrylonitrile; celluloid; engineering plastics such as polycarbonate and polyimide. These resins can be used individually or in combination of two or more.

[0041] Examples of resin substrate 10 include single-layer films composed of a single resin, and single-layer or laminated films using multiple resins. Alternatively, laminated substrates formed by laminating the aforementioned resins onto other substrates (metal, wood, paper, ceramics, etc.) can also be used. Resin substrate 10 can be single-layered or composed of two or more layers. Preferred resin substrates 10 include polyolefin-based resin films (especially polyethylene films, polypropylene films, etc.), polyester-based resin films (especially polyethylene terephthalate-based resin films), and polyamide-based resin films (especially nylon films).

[0042] The resin substrate 10 can be an unstretched film, or a uniaxial or biaxially stretched oriented film. From the viewpoint of excellent water vapor barrier properties, polyethylene film, polypropylene film, and particularly biaxially stretched polypropylene film (OPP) are preferred as the resin substrate 10. OPP can be obtained by processing at least one polymer selected from homopolymers, random copolymers, and block copolymers into a film form. Homopolymers are polypropylene composed solely of propylene monomers. Random copolymers are polypropylene that has undergone random copolymerization of propylene as the main monomer and a small amount of comonomers different from propylene to form a homogeneous phase. Block copolymers are polypropylene that has undergone block copolymerization of propylene as the main monomer with the aforementioned comonomers, or by rubber-like polymerization to form a heterogeneous phase. When the resin substrate 10 is OPP, the OPP can be one layer or two or more layers.

[0043] Surface treatments such as chemical treatment, solvent treatment, corona treatment, low-temperature plasma treatment, and ozone treatment can be applied to one side 12 of the resin substrate 10 to improve its adhesion to the base layer 30 or the inorganic oxide layer 40.

[0044] The resin base material 10 may contain additives such as fillers, anti-blocking agents, antistatic agents, plasticizers, lubricants, and antioxidants. These additives may be used individually or in combination of two or more.

[0045] When the resin substrate 10 contains an anti-blocking agent (hereinafter also referred to as "AB agent"), an unevenness caused by the AB agent is formed on one surface 12 of the resin substrate 10. By containing the AB agent, the surface of the resin substrate 10 is given a protrusion, thereby suppressing the adhesion of the film. That is, by containing the AB agent, the resin substrate 10 improves the anti-blocking properties of the film. Therefore, the film can be easily wound up, thereby improving the processing characteristics of the film. Therefore, the resin substrate 10 preferably contains the AB agent. On the other hand, when a large protrusion is formed on one surface 12 of the resin substrate 10, defects that act as pathways for gas permeation are easily generated in the base layer 30, the inorganic oxide layer 40, and the oxygen barrier coating 20 formed thereon. Therefore, the oxygen barrier properties of the gas barrier film 1 may be reduced.

[0046] When the resin substrate 10 contains an AB agent, the AB agent is dispersed in the resin substrate 10. Multiple protrusions from the AB agent are locally present on one side 12 or the other side 14 of the resin substrate 10. In one side 12 and the other side 14, the AB agent may be exposed or covered by the resin.

[0047] AB agents are solid particles, which can be organic or inorganic. Examples of organic particles include polymethyl methacrylate (PMMA) particles, polystyrene particles, and polyamide particles. These organic particles can be obtained, for example, through emulsion polymerization or suspension polymerization. Examples of inorganic particles include silica particles, zeolite, talc, kaolin, and feldspar. Any one of these AB agents can be used alone, or two or more can be used in combination.

[0048] When considering the appearance, transparency, likelihood of AB agent detachment, and anti-blocking properties of the gas barrier film 1, the average particle size of the AB agent is preferably, for example, 0.1 to 5 μm. The average particle size of the AB agent is the weight-average diameter determined by the Coulter method.

[0049] When the resin substrate 10 contains an AB agent, the content of the AB agent is preferably, for example, 0.05 to 0.5 parts by mass relative to 100 parts by mass of the resin constituting the resin substrate 10. When the content of the AB agent is above the lower limit mentioned above, it is easy to improve the processing characteristics of the film used as a raw material for the resin substrate 10. When the content of the AB agent is below the upper limit mentioned above, it is easy to suppress the decrease in the oxygen barrier properties of the gas barrier film 1.

[0050] The black area ratio of one surface 12 of the resin substrate 10 is 0.15% or less, more preferably 0.12% or less, and even more preferably 0.10% or less. When the black area ratio is below the above-mentioned upper limit value, it is easy to further improve the oxygen barrier properties of the gas barrier film 1. In addition, when the black area ratio is below the above-mentioned upper limit value, it is particularly easy to make the printability of the gas barrier film 1 using polypropylene film or polyethylene terephthalate resin film good. There is no particular limitation on the lower limit value of the black area ratio, which is 0% or more.

[0051] Here, "good printing adaptability" means suppressing ink leakage (sometimes called ink drop) in the highlight areas (printed areas with low dot area ratio) during gravure printing on the oxygen barrier coating 20 of the gas barrier film. The black area ratio can be adjusted, for example, according to the material, average particle size and content of the AB agent contained in the resin substrate 10, the characteristics of the resin forming one side 12 of the resin substrate 10, and the film manufacturing conditions.

[0052] When the brightness of the surface of the resin substrate 10 is binarized and observed using an electron microscope in areas that appear black (black spots), protrusions are present. The larger the size of the black spots, the higher the height of the protrusions tends to be, especially in areas with a size of 100 μm. 2In the areas with the aforementioned black dots (protrusions), coating defects in the oxygen barrier film and ink omissions during printing are prone to occur. That is, the smaller the black area ratio, the fewer protrusions on one side 12 of the resin substrate 10 that adversely affect oxygen barrier properties and printability, which can further improve the oxygen barrier properties of the gas barrier film 1 and make the printability good.

[0053] The black area ratio in this specification can be determined by the following measurement method.

[0054] <Determination Method>

[0055] An arbitrary area of ​​1281 μm square on one side 12 of the resin substrate 10 was photographed using an optical microscope to obtain a 1024 × 1024 pixel image. An example of the captured image is shown below. Figure 2 As shown.

[0056] Figure 2 This is an image obtained by taking a picture of one surface 12 of a resin substrate 10 using an optical microscope. Figure 2 In this diagram, 100 represents a flat area, and 110 represents a protrusion. Examples of protrusions 110 include foreign matter, AB agent, and resin dissolution residue. Figure 2 As shown, the flat portion 100 appears gray, and the protrusion 110 appears black. The brightness of the flat portion 100 corresponds to the most frequent value of brightness, which will be described later.

[0057] Next, image analysis software was used to convert the acquired 1024×1024 pixel image into a 256 grayscale monochrome image. The brightness distribution of the converted monochrome image was plotted to create a histogram. An example of a histogram is shown below. Figure 3 As shown.

[0058] exist Figure 3 In the diagram, the horizontal axis represents the brightness after conversion to a 256-grayscale monochrome image. The brightness in a monochrome image is an integer from 0 to 255. The vertical axis represents the frequency of brightness. Figure 3 In the image, the minimum value of the distributed brightness is 26, and the maximum value is 255. The most frequent value of brightness is the value of the brightness that is most frequently distributed in the monochrome image. Figure 3 In this context, P represents the most frequent value of brightness. Figure 3 In this case, P = 160.

[0059] Next, the value obtained by subtracting 30 from the most frequent brightness value is used as a threshold. Values ​​below the threshold are set to black, and values ​​above the threshold are set to white, thus binarizing the brightness in the monochrome image. Figure 3 In a monochrome image, the threshold that separates black from white is the value obtained by subtracting 30 from the most frequent value of brightness (P-30). Figure 3 In this context, the threshold is 130. That is, in... Figure 3 In the process, colors with a brightness less than 130 are set to "black" and colors with a brightness greater than 130 are set to "white" for binarization.

[0060] From the viewpoint of improving the accuracy of the black area ratio value, the brightness histogram of the obtained image is preferably sharp in shape. Here, "sharp in shape" can be determined, for example, by the size of the width (hereinafter also referred to as "half-value width") W of the histogram, which is half the height (H / 2) of the peak height H of the most frequent value P of the histogram. The half-value width W is preferably 30 or less, more preferably 20 or less, and even more preferably 10 or less. When the half-value width W is below the above-mentioned upper limit value, the histogram has a sharp shape, and the accuracy of the black area ratio value is improved. There is no particular limitation on the lower limit value of the half-value width W, but it is substantially 2 or more.

[0061] Based on the binarized 1281×1281μm (1024×1024 pixels) image above, the size is 100μm. 2 The proportion of the total area of ​​the black regions mentioned above is called the black area ratio. Furthermore, the black area ratio is the arithmetic mean of the values ​​calculated from any three regions.

[0062] As an optical microscope, the Olympus "OLS-4000" optical microscope manufactured by Olympus Corporation is preferred. As an image analysis software, Scion "Scion ImageJ" from Scion Corporation is preferred.

[0063] The conditions for obtaining the image are explained.

[0064] (Image acquisition conditions)

[0065] With the side of the resin substrate 10 to which the coating agent is to be applied (one side 12) facing upwards, use black double-sided adhesive tape (Teraoka Manufacturing Co., Ltd., 7694) to attach the resin substrate 10 to a glass slide. Using an optical microscope (Olympus Corporation, OLS-4000) and a 10x objective lens (MPFLN10), acquire images of 1281μm × 1281μm from any three points on the resin substrate 10 on the glass slide to obtain 1024 × 1024 pixel images. The amount of light during image acquisition is arbitrary, but it is preferable to adjust the amount of light so that the most frequent value of the image brightness in 256 grayscale is controlled within the range of 80 to 200.

[0066] The image analysis conditions are as follows.

[0067] (Image analysis conditions)

[0068] • Color information corruption: 8-bit.

[0069] • Threshold for binarization: The value obtained by subtracting 30 from the most frequent value of brightness.

[0070] • Range settings: Set scale distance in pixel: 1024, Known distance: 1281, Unit of length: μm

[0071] • Area determination: Analyze particle size: 100 - Infinity (μm) 2 This includes include holes and summarize checks.

[0072] Under the above image analysis conditions, the %Area value is calculated for each of the images taken from any three locations on the resin substrate 10, and the arithmetic mean of these %Area values ​​is taken as the black area ratio.

[0073] The black area ratio in this specification is calculated by observing one surface 12 of the resin substrate 10 on a plane. Therefore, compared with the conventional measurement of surface roughness, the surface condition can be observed on a surface rather than on a line.

[0074] Traditional surface roughness values ​​vary depending on the measurement method and range. When the measurement area is narrow, it is impossible to measure a small number of protrusions, so the roughness may be underestimated. In addition, even when roughness is measured over a straight line of a certain length, such as centerline average roughness, the roughness will be estimated larger if large protrusions are measured, but will still be estimated smaller in other cases.

[0075] As described in this specification, by defining the surface condition of the resin substrate using the black area ratio, deviations in the surface condition of the resin substrate can be reduced and the surface condition of the resin substrate can be evaluated. Therefore, deviations in oxygen barrier properties can be suppressed, thereby easily further improving the oxygen barrier properties of the gas barrier film 1.

[0076] Using binarization of optical microscope images to manage black area ratio is suitable for managing oxygen barrier properties and printability due to its wide measurement range and the ease with which protrusions can be detected.

[0077] The thickness of the resin substrate 10 is not particularly limited, and its suitability as a packaging material and its suitability for lamination with other coatings can be considered and appropriately selected according to price and application. The thickness of the resin substrate 10 is substantially preferably 3 μm to 200 μm, more preferably 5 μm to 120 μm, further preferably 6 μm to 100 μm, and particularly preferably 10 μm to 30 μm.

[0078] <Basal layer>

[0079] The base layer 30 is disposed between the resin substrate 10 and the inorganic oxide layer 40 or the oxygen barrier coating 20.

[0080] The base layer 30 is a layer containing organic polymers as its main component, also known as the primer layer. By setting the base layer 30, the film-forming properties and adhesion strength of the inorganic oxide layer 40 or the oxygen barrier coating 20 can be improved.

[0081] The content of the organic polymer in the substrate layer 30 can be, for example, 70% by mass or more, or 80% by mass or more. Examples of such organic polymers include: polyacrylic acid resin, polyester resin, polycarbonate resin, polyurethane resin, polyamide resin, polyolefin resin, polyimide resin, melamine resin, phenolic resin, etc. When considering the hot water resistance and adhesion strength between the resin substrate 10 and the inorganic oxide layer 40 or the oxygen barrier coating 20, it is preferable to contain at least one of polyacrylic acid resin, polyol resin, polyurethane resin, polyamide resin, or reaction products of these organic polymers. Additionally, the substrate layer 30 may also contain a silane coupling agent, an organotitanate, or a modified silicone oil.

[0082] The organic polymer may be further preferably exemplified as: an organic polymer having a carbamate bond generated by reacting a polyol having two or more hydroxyl groups at the polymer terminal with an isocyanate compound; and / or an organic polymer comprising the reaction product of a polyol having two or more hydroxyl groups at the polymer terminal with an organosilane compound such as a silane coupling agent or its hydrolysate.

[0083] Examples of polyols include at least one selected from acrylic polyols, polyvinyl acetals, polystyrene polyols, and polyurethane polyols. Acrylic polyols can be obtained by polymerizing acrylic derivative monomers or by copolymerizing acrylic derivative monomers with other monomers. Examples of acrylic derivative monomers include ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Examples of monomers copolymerized with acrylic derivative monomers include styrene.

[0084] Isocyanate compounds enhance the adhesion between the resin substrate 10 and the inorganic oxide layer 40 or the oxygen barrier coating 20 by reacting with polyols to form urethane bonds. In other words, the isocyanate compound acts as a crosslinking agent or curing agent. Examples of isocyanate compounds include, for instance, aromatic compounds such as toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI); aliphatic compounds such as phenylenediamine diisocyanate (XDI) and hexamethylene diisocyanate (HMDI); and isophorone diisocyanate (IPDI), as well as their polymers and derivatives. The aforementioned isocyanate compounds can be used alone or in combination of two or more.

[0085] Examples of silane coupling agents include, for example, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, propylene oxide propyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane. Organosilane compounds can also be hydrolysates of these silane coupling agents. Organosilane compounds can include one of the above-mentioned silane coupling agents and their hydrolysates, or they can combine two or more of them.

[0086] A mixture can be prepared by mixing the above components in an organic solvent in any proportion, and the prepared mixture can be used to form a base layer 30 on one side 12 of the resin substrate 10. The mixture may also contain, for example, curing accelerators such as tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts; antioxidants such as phenolic, sulfur-based, and phosphite-based agents; leveling agents, flow modifiers, catalysts, crosslinking reaction promoters, and fillers.

[0087] The mixture can be applied to the resin substrate 10 using known printing methods such as offset printing, gravure printing, or screen printing; or known coating methods such as roller coating, air knife coating, or gravure coating. After coating, the base layer 30 can be formed, for example, by heating to 50–200°C and drying and / or curing.

[0088] There is no particular limitation on the thickness of the substrate 30; for example, it can be 0.005–5 μm. The thickness can be adjusted according to the application or required properties.

[0089] The thickness of the base layer 30 is preferably 0.01 to 1 μm, more preferably 0.01 to 0.5 μm. If the thickness of the base layer 30 is 0.01 μm or more, sufficient adhesion strength can be obtained between the resin substrate 10 and the inorganic oxide layer 40 or the oxygen barrier coating 20, thereby ensuring good oxygen barrier properties. If the thickness of the base layer 30 is 1 μm or less, a uniform coating surface can be easily formed, and the drying load and manufacturing cost can be suppressed.

[0090] <Inorganic oxide layer>

[0091] Inorganic oxide layer 40 can be, for example, aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, tin oxide, zinc oxide, indium oxide, etc., especially aluminum oxide or silicon oxide, which have excellent manufacturability and excellent oxygen and water vapor barrier properties under heat and humid heat, and are therefore preferred. It should be noted that inorganic oxide layer 40 may contain one of these alone, or may contain two or more in combination.

[0092] The thickness of the inorganic oxide layer 40 is preferably 1 to 200 nm. If the thickness is 1 nm or more, excellent oxygen barrier and water vapor barrier properties can be obtained. If the thickness is less than 200 nm, the manufacturing cost can be controlled to a lower level, and it is difficult to generate cracks caused by external forces such as bending or stretching, thereby suppressing the deterioration of barrier properties.

[0093] The inorganic oxide layer 40 can be formed, for example, by known film formation methods such as vacuum evaporation, sputtering, ion plating, or plasma vapor deposition (CVD).

[0094] <Oxygen Barrier Coating>

[0095] It is known that the oxygen barrier coating 20 can be an oxygen barrier coating formed by a wet coating method. The oxygen barrier coating 20 can be obtained by forming a coating film composed of a coating agent on a substrate layer 30 or an inorganic oxide layer 40 by a wet coating method, and then drying the coating film. It should be noted that the coating film is a wet film, and the coating film is a dry film.

[0096] As an oxygen barrier coating 20, it is preferably a coating containing at least one of a metal alkoxide and its hydrolysate and its reaction product, and a water-soluble polymer (organic-inorganic composite coating). Furthermore, it is preferably a coating that further contains at least one of a silane coupling agent and its hydrolysate.

[0097] Metal alkoxides and their hydrolysates contained in organic-inorganic composite membranes include, for example, tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which are derived from the general formula: M(OR). nThe compound and its hydrolysate are represented. It may contain one of these compounds alone, or it may contain two or more in combination.

[0098] In organic-inorganic composite membranes, the total content of at least one of the metal alkoxides, their hydrolysates, and reaction products is, for example, 40–70% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the total content of at least one of the metal alkoxides, their hydrolysates, and reaction products in organic-inorganic composite membranes can be 50% by mass. From the same viewpoint, the upper limit of the total content of at least one of the metal alkoxides, their hydrolysates, and reaction products in organic-inorganic composite membranes can be 65% by mass.

[0099] There are no particular limitations on the water-soluble polymers contained in the organic-inorganic composite membrane. Examples include: polyvinyl alcohol-based polymers; polysaccharides such as starch, methylcellulose, and carboxymethylcellulose; and acrylic polyol-based polymers. From the viewpoint of further improving oxygen barrier properties, polyvinyl alcohol-based polymers are preferred. The number-average molecular weight of the water-soluble polymers is, for example, 40,000 to 180,000.

[0100] Water-soluble polymers based on polyvinyl alcohol can be obtained, for example, by saponifying (including partially saponifying) polyvinyl acetate. These water-soluble polymers may contain tens of percent or only a few percent of acetic acid groups.

[0101] The content of water-soluble polymers in organic-inorganic composite membranes is, for example, 15–50% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the content of water-soluble polymers in organic-inorganic composite membranes can be 20% by mass. From the viewpoint of further reducing oxygen permeability, the upper limit of the content of water-soluble polymers in organic-inorganic composite membranes can be 45% by mass.

[0102] Silane coupling agents and their hydrolysates contained in organic-inorganic composite membranes can be categorized as having organic functional groups. Examples of such silane coupling agents and their hydrolysates include: ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and their hydrolysates. One of these can be contained alone, or two or more can be contained in combination.

[0103] At least one of the silane coupling agent and its hydrolysate is preferably a silane coupling agent having an epoxy group as an organic functional group. Examples of epoxy-containing silane coupling agents include γ-epoxypropoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Epoxy-containing silane coupling agents and their hydrolysates may also have organic functional groups different from the epoxy group, such as vinyl, amino, methacrylate, or urea groups.

[0104] Silane coupling agents with organic functional groups and their hydrolysates can further improve the oxygen barrier properties of the oxygen barrier coating 20 and its adhesion to the substrate layer 30 or the inorganic oxide layer 40 through the interaction of their organic functional groups with the hydroxyl groups of water-soluble polymers. In particular, by allowing the epoxy groups of the silane coupling agent and its hydrolysates to interact with the hydroxyl groups of polyvinyl alcohol, an oxygen barrier coating 20 with particularly excellent oxygen barrier properties and adhesion to the substrate layer 30 or the inorganic oxide layer 40 can be formed.

[0105] In organic-inorganic composite membranes, the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products is, for example, 1 to 15% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 2% by mass. From the same viewpoint, the upper limit of the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 12% by mass.

[0106] Organic-inorganic composite membranes may also contain crystalline inorganic layered compounds with a layered structure. Examples of inorganic layered compounds include clay minerals such as those from the kaolinite, montmorillonite, or mica groups. One or more of these compounds may be used alone or in combination. The particle size of the inorganic layered compounds is, for example, 0.1–10 μm. The aspect ratio of the inorganic layered compounds is, for example, 50–5000.

[0107] As inorganic layered compounds, by introducing water-soluble polymers into the interlayer spaces of the layered structure, a coating with excellent oxygen barrier properties and strong adhesion can be formed. Therefore, clay minerals of the montmorillonite group are preferred. Specific examples of clay minerals of the montmorillonite group include montmorillonite, hydropyrite, bentonite, and water-swellable synthetic mica.

[0108] Another preferred example of the oxygen barrier coating 20 is a coating containing a polycarboxylic acid polyvalent metal salt (PCISS) as a reaction product of the carboxyl group of a polycarboxylic acid polymer (A) and a polyvalent metal compound (B). In this case, the PCISS can be formed by coating a coating agent containing a mixture of polycarboxylic acid polymer (A) and polyvalent metal compound (B) and heating and drying; or by coating a coating agent with polycarboxylic acid polymer (A) as the main component and drying to form a coating A, and then coating a coating agent with polyvalent metal compound (B) as the main component on it and drying to form a coating B, thereby forming a PCISS through a cross-linking reaction between the A / B layers.

[0109] [Polycarboxylate polymer (A)]

[0110] Polycarboxylate polymers are polymers with two or more carboxyl groups within their molecules. Examples of polycarboxylate polymers include (co)polymers of olefinically unsaturated carboxylic acids; copolymers of olefinically unsaturated carboxylic acids with other olefinically unsaturated monomers; and acidic polysaccharides containing carboxyl groups, such as alginate, carboxymethyl cellulose, and pectin. Examples of olefinically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of olefinically unsaturated monomers that can copolymerize with olefinically unsaturated carboxylic acids include: ethylene, propylene, vinyl acetate, and other saturated carboxylic acid vinyl esters; alkyl acrylates, alkyl methacrylates, alkyl itaconic acid esters, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. These polycarboxylate polymers can be used individually or in mixtures of two or more.

[0111] From the viewpoint of the gas barrier properties of the resulting gas barrier membrane 1, the polymers described above preferably include constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid. Polymers particularly preferred are those comprising constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid. In this polymer, the proportion of constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 80 mol% or more, more preferably 90 mol% or more (wherein the total of all constituent units constituting the polymer is set to 100 mol%). This polymer can be a homopolymer or a copolymer. When the polymer is a copolymer containing constituent units other than those described above, examples of other constituent units include constituent units derived from olefinically unsaturated monomers that can copolymerize with the aforementioned olefinically unsaturated carboxylic acids.

[0112] The number-average molecular weight of the polycarboxylate polymer is preferably in the range of 2,000 to 10,000,000, more preferably 5,000 to 1,000,000. When the number-average molecular weight is less than 2,000, the resulting gas-barrier film cannot achieve sufficient water resistance, and sometimes the gas barrier properties and transparency deteriorate due to moisture, or sometimes whitening occurs. On the other hand, when the number-average molecular weight exceeds 10,000,000, the viscosity of the coating agent used to form the oxygen barrier coating 20 becomes high, which may sometimes impair the coatability. It should be noted that the above-mentioned number-average molecular weight is the number-average molecular weight converted from polystyrene obtained by gel permeation chromatography (GPC).

[0113] In the case of coating an agent with polycarboxylate polymer (A) as the main component and drying it to form film A, and then forming film B, a portion of the carboxyl groups of the polycarboxylate polymer can be neutralized beforehand with an alkaline compound. By pre-neutralizing a portion of the carboxyl groups present in the polycarboxylate polymer, the water resistance and heat resistance of film A can be further improved. Preferably, the alkaline compound is at least one selected from the group consisting of a polyvalent metal compound, a monovalent metal compound, and ammonia. As the polyvalent metal compound, compounds exemplified in the description of polyvalent metal compound (B) described later can be used. Examples of monovalent metal compounds include sodium hydroxide and potassium hydroxide.

[0114] Various additives can be added to coating agents with polycarboxylate polymers (A) as the main component. Within the range that does not impair the barrier properties, crosslinking agents, curing agents, leveling agents, defoamers, antiblocking agents, antistatic agents, dispersants, surfactants, softeners, stabilizers, film-forming agents, thickeners, etc. can be added.

[0115] The solvent used in coating agents with polycarboxylate polymers (A) as the main component is preferably an aqueous medium. Examples of aqueous mediums include water, water-soluble or hydrophilic organic solvents, or mixtures thereof. Aqueous mediums typically contain water or have water as the main component. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more. Examples of water-soluble or hydrophilic organic solvents include, for example: alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosols; carbitols; and nitrile compounds such as acetonitrile.

[0116] [Polyvalent metal compound (B)]

[0117] There are no particular limitations on the type of polyvalent metal compound that can react with the carboxyl groups of polycarboxylate polymers to form polycarboxylate polyvalent metal salts; examples include zinc oxide particles, magnesium oxide particles, magnesium methoxide, copper oxide, and calcium carbonate. These can be used alone or in combination. From the viewpoint of oxygen barrier properties in oxygen barrier coatings, zinc oxide is preferred.

[0118] Zinc oxide is an inorganic material with ultraviolet absorption properties. There is no particular limitation on the average particle size of zinc oxide particles, but from the viewpoints of gas barrier properties, transparency, and coating suitability, the average particle size is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0119] When coating an agent with a polyvalent metal compound (B) as the main component and drying it to form a film, various additives other than zinc oxide particles may be included as needed, without impairing the effects of the present invention. These additives may include: resins soluble or disperseable in the solvent used in the coating agent, dispersants soluble or disperseable in the solvent, surfactants, softeners, stabilizers, film-forming agents, thickeners, etc.

[0120] In the above-mentioned applications, it is preferable to include a resin that can be dissolved or dispersed in a solvent used in the coating agent. This improves the coatability and film-forming properties of the coating agent. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenolic resins, amino resins, fluororesins, epoxy resins, and isocyanate resins.

[0121] Furthermore, it is preferable to contain a dispersant that can be dissolved or dispersed in the solvent used in the coating agent. This improves the dispersibility of the polyvalent metal compound. Anionic or nonionic surfactants can be used as this dispersant. Examples of surfactants include: (poly)carboxylates, alkyl sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, aromatic phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, alkyl allyl sulfates, polyoxyethylene alkyl phosphates, sorbitol alkyl esters, glycerol fatty acid esters, sorbitol fatty acid esters, sucrose fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene sorbitol alkyl esters, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and various other surfactants. These surfactants can be used alone or in mixtures of two or more.

[0122] When the coating agent, whose main component is a polyvalent metal compound (B), contains additives, the mass ratio of the polyvalent metal compound to the additive (polyvalent metal compound: additive) is preferably in the range of 30:70 to 99:1, more preferably in the range of 50:50 to 98:2.

[0123] Solvents used in coating agents whose main component is a polyvalent metal compound (B) include, for example, water, methanol, ethanol, isopropanol, n-propanol, n-butanol, n-pentanol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents can be used individually or in mixtures of two or more. From the viewpoint of coatability, methanol, ethanol, isopropanol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of manufacturability, methanol, ethanol, isopropanol, and water are preferred.

[0124] In the case of coating and drying a coating agent containing a polycarboxylate polymer (A) and a polyvalent metal compound (B) to form a polycarboxylate polyvalent metal salt film, the polycarboxylate polymer (A), the polyvalent metal compound (B), water or an alcohol as a solvent, a resin or dispersant soluble or dispersed in the solvent, and additives as needed are mixed as a coating agent, and then coated and dried using a known coating method to form a polycarboxylate polyvalent metal salt film. Examples of coating methods include casting, dipping, roller coating, gravure coating, screen printing, reverse coating, spraying, overcoating, die coating, metering bar coating, chamber air knife combined coating, and curtain coating.

[0125] The thickness of the oxygen barrier coating 20 can be set according to the desired oxygen barrier performance, for example, it can be 0.05 to 5 μm. Preferably, the thickness of the oxygen barrier coating 20 is 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. If the thickness of the oxygen barrier coating 20 is 0.05 μm or more, sufficient oxygen barrier performance is easily obtained. If the thickness of the oxygen barrier coating 20 is 1 μm or less, a uniform coating surface is easily formed, and drying load and manufacturing costs can be suppressed, thereby increasing the usefulness of using the resin substrate 10, which is a feature of this disclosure, having a surface with a black area ratio of 0.15% or less.

[0126] As an oxygen barrier film 20, the gas barrier film having the above-mentioned organic-inorganic composite film or the above-mentioned polycarboxylate polyvalent metal salt film can exhibit excellent oxygen barrier properties even after boiling or sterilization treatment. When laminated with a sealant film, it has sufficient sealing strength and tightness even as a packaging material for boiling or sterilization treatment. In addition, it has the following advantages: transparency not found in metal foil or metal vapor-deposited film, excellent bending and tensile strength, and no risk of generating harmful substances such as dioxins.

[0127] [Manufacturing method of gas barrier membrane]

[0128] The gas barrier membrane 1 can be manufactured by forming a base layer 30 or an inorganic oxide layer 40, or both, on one side 12 of a resin substrate 10, and then forming an oxygen barrier coating 20 on the base layer 30 or the inorganic oxide layer 40.

[0129] The method for manufacturing the gas barrier membrane 1 disclosed herein includes, for example, a sorting process, a substrate layer formation process, an inorganic oxide layer formation process, and an oxygen barrier coating formation process.

[0130] As a sorting process, for example, a process can be listed where resin substrate raw materials with a black area ratio of 0.15% or less on the surface are sorted as resin substrates. The black area ratio of the surface of the resin substrate raw material is measured by the same method as the method for measuring the black area ratio of one surface 12 of the resin substrate 10 described above.

[0131] As the resin substrate 10, commercially available products or substrates manufactured by known methods can be used.

[0132] As a base layer forming process, for example, the following steps can be listed: applying a coating agent to at least one side 12 of the resin substrate 10 by wet coating to form a coating film, and drying the coating film (removing the solvent) to form a base layer 30.

[0133] As a coating agent, a known wet coating method can be used. Examples of wet coating methods include: roller coating, gravure coating, reverse coating, mold coating, screen printing, and spray coating.

[0134] As a method for drying the coating film composed of the coating agent, known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used. The drying temperature of the coating film is preferably, for example, 50 to 200°C. The drying time varies depending on the thickness of the coating film, the drying temperature, etc., but is preferably, for example, 1 second to 5 minutes.

[0135] As an inorganic oxide layer formation process, the following process can be listed as an example: forming an inorganic oxide layer 40 on one side 12 of the resin substrate 10 or the base layer 30 using the above-mentioned vacuum evaporation method, sputtering method, ion plating method or plasma vapor deposition method (CVD).

[0136] As an oxygen barrier coating forming process, the following steps can be listed as an example: applying a coating agent to a substrate layer 30 or an inorganic oxide layer 40 by wet coating to form a coating film, and drying the coating film (removing the solvent) to form an oxygen barrier coating 20.

[0137] As a coating agent, a known wet coating method can be used. Examples of wet coating methods include: roller coating, gravure coating, reverse coating, mold coating, screen printing, and spray coating.

[0138] As a method for drying the coating film composed of the coating agent, known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used. The drying temperature of the coating film is preferably, for example, 50 to 200°C. The drying time varies depending on the thickness of the coating film, the drying temperature, etc., but is preferably, for example, 1 second to 5 minutes.

[0139] The oxygen barrier coating 20 can be formed by applying and drying it once, or by applying the same coating agent or different coating agents multiple times and drying them.

[0140] In the base layer formation process, the inorganic oxide layer formation process, and the oxygen barrier coating formation process, a base layer 30, an inorganic oxide layer 40, or an oxygen barrier coating 20 is formed on one side 12 of the resin substrate 10. At this time, the black area ratio of one side 12 is 0.15% or less. Alternatively, the base layer 30, the inorganic oxide layer 40, or the oxygen barrier coating 20 may be formed on both sides of the resin substrate 10. In this case, the black area ratio of the other side 14 of the resin substrate 10 is 0.15% or less.

[0141] When a base layer 30, an inorganic oxide layer 40, or an oxygen barrier coating 20 is formed on both sides of a resin substrate, the oxygen barrier properties are further improved and the printability is good when the black area ratio of both sides of the resin substrate is less than 0.15%, which is therefore preferred.

[0142] When the method for manufacturing the gas barrier film 1 disclosed herein includes a sorting step, resin substrates with a black area ratio of 0.15% or less on the surface can be effectively applied. Therefore, by including the sorting step, the gas barrier film 1 with further improved oxygen barrier properties can be effectively manufactured. In addition, by including the sorting step, the gas barrier film 1 with good printability can be effectively manufactured.

[0143] As needed, the gas barrier film 1 disclosed herein may further have a printing layer, a protective layer, a light-shielding layer, an adhesive layer, a heat-sealable heat-melting layer, and other functional layers.

[0144] In the case where the gas barrier film 1 of this disclosure has a heat-sealable heat-sealing layer, the heat-sealing layer is disposed on at least one outermost layer of the gas barrier film 1. Since the gas barrier film 1 has a heat-sealing layer, the gas barrier film 1 can be sealed by heat sealing (e.g., packaging, cap).

[0145] For example, in a laminate obtained by forming the base layer 30, inorganic oxide layer 40, and oxygen barrier coating 20 of this embodiment on one or both sides of a resin substrate, known adhesives such as polyurethane, polyester, and polyether can be used, and the heat-fused layer can be laminated by known dry lamination, extrusion lamination, or the like.

[0146] <Effects>

[0147] For the gas barrier film 1 of this disclosure, the brightness in the monochrome image is binarized, and the size of 100 μm is calculated. 2 The total area ratio of the black areas mentioned above (black area ratio). An oxygen barrier coating 20 is laminated on at least one surface of the resin substrate 10 with a black area ratio of 0.15% or less via a base layer 30 or an inorganic oxide layer 40, or both the base layer 30 and the inorganic oxide layer 40.

[0148] In the gas barrier film 1 disclosed herein, an oxygen barrier coating 20 is formed on the surface of a resin substrate 10 with a black area ratio of 0.15% or less via a base layer 30 or an inorganic oxide layer 40, or both. Therefore, film defects caused by large protrusions on the substrate surface are less likely to occur, and oxygen barrier properties are easily further improved. Furthermore, the printability of the gas barrier film 1 is also improved.

[0149] Therefore, by using the gas barrier film 1 disclosed herein as a packaging material, the quality retention of the contents can be improved at a low cost.

[0150] Furthermore, by using the gas barrier film 1 disclosed herein as a packaging material, printing can be performed easily and aesthetically.

[0151] (Implementation Method 2)

[0152] As mentioned above, gas barrier films obtained by applying a coating to the surface of a resin substrate using methods such as wet coating, vapor deposition, and sputtering can sometimes exhibit unstable oxygen barrier properties due to variations in production batches. Specifically, the oxygen barrier properties of the gas barrier film are worse than the original oxygen barrier properties, i.e., the oxygen barrier properties assumed based on the materials constituting the coating and the thickness of the coating. This problem tends to occur particularly easily when the coating thickness becomes thinner. Therefore, the thickness of the gas barrier layer must be increased to a thickness greater than the required thickness, resulting in poor production efficiency and excessively high material costs.

[0153] In addition, polyolefin resin films, which are used as resin base materials, are inexpensive and have high water vapor barrier properties, and are often used as packaging materials. However, they have poor adhesion to gas barrier films, resulting in the following disadvantages: poor lamination strength when laminated with heat-sealable resin films to make gas barrier packaging materials.

[0154] The purpose of Embodiment 2 is to provide a gas barrier film and a method thereof that can fully exhibit its original oxygen barrier properties and excellent gas barrier properties even when the thickness of the coating used to impart oxygen barrier properties is reduced, and that has sufficient sealing strength as a packaging material.

[0155] To investigate the causes of the aforementioned problems, the inventors used an optical microscope or an electron microscope to observe in detail the surface and cross-section of the gas-barrier film with poor oxygen barrier properties. In the areas where an anti-blocking agent (hereinafter also referred to as "AB agent") was added to prevent adhesion of the resin substrate, cross-sectional electron microscopy was performed using a focused ion / electron beam processing observation device. The results confirmed that defects with a width of several μm were generated in the coating in areas where the AB agent was highly prominent (an example of a cross-sectional electron microscopy image is shown below). Figure 8 (As shown). It is believed that this coating defect becomes a pathway for gas permeation, thus failing to adequately demonstrate oxygen barrier properties. The surface of the resin substrate contains protrusions of various sizes generated by the AB agent. It is believed that the protrusion height and density of the AB agent vary between different production batches of the resin substrate. When a gas-barrier coating (oxygen barrier coating) is applied to the surface of this resin substrate, defects are locally created at locations with large protrusions, resulting in unstable oxygen barrier properties.

[0156] Therefore, the inventors devised a method for accurately grasping the surface state of a resin substrate that affects the oxygen barrier properties of the gas barrier membrane over a short period of time, thereby completing this disclosure.

[0157] [1] An oxygen barrier membrane comprising a resin substrate and an oxygen barrier coating formed on one side of the resin substrate, namely a first side, wherein at least one of a base layer and an inorganic oxide layer is provided between the resin substrate and the oxygen barrier coating, the resin substrate having two or more resin layers, wherein the resin layer forming the first side is composed of a polyolefin copolymer resin, and wherein on the first side, there are 20 protrusions with a Feret's diameter of 8 μm or more as measured by the following measurement method. 2 the following.

[0158] <Determination Method>

[0159] Using a white LED line light source, an arbitrary area of ​​36.6 mm square on the first surface of the resin substrate is illuminated at a distance of 100 mm and an incident angle of 83°. A monochrome line scan camera is used to capture transmitted light at a measurement angle of 90° to obtain an image. An analytical image of 3551 pixels × 5684 pixels (2.5 × 4.0 mm) is cropped from the captured image, and protrusions with a Feretta diameter of 8 μm or more in the analytical image are counted.

[0160] [2] A gas barrier membrane, wherein the resin substrate is a polyolefin resin.

[0161] [3] A gas barrier membrane, wherein the thickness of the substrate layer is 0.01 to 1 μm.

[0162] [4] A gas barrier membrane, wherein the base layer contains an organic polymer as a main component, the organic polymer comprising at least one of polyacrylic resin, polyol resin, polyurethane resin, polyamide resin, or reaction products of these organic polymers.

[0163] [5] A barrier membrane, wherein the thickness of the inorganic oxide layer is 1 to 200 nm.

[0164] [6] A gas barrier membrane, wherein the inorganic oxide layer is aluminum oxide or silicon oxide.

[0165] [7] An oxygen barrier membrane, wherein the thickness of the oxygen barrier coating is 0.05 to 1 μm.

[0166] [8] An oxygen barrier membrane, wherein the oxygen barrier membrane is a membrane comprising at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer.

[0167] [9] An oxygen barrier membrane, wherein the oxygen barrier membrane further comprises at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

[0168]

[10] An oxygen barrier membrane, wherein the oxygen barrier membrane comprises a carboxylic acid polyvalent metal salt as a reaction product of the carboxyl group of a polycarboxylic acid polymer (A) and a polyvalent metal compound (B).

[0169]

[11] A method for manufacturing a gas barrier film, which is a method for manufacturing a gas barrier film as described in any one of [1] to

[10] , comprising: determining the number of protrusions on one side of a resin substrate by the following measurement method, and setting the number of protrusions with a Fehle diameter of 8 μm or more to 20 per mm. 2 The following process includes using the following resin substrate as the resin substrate; and applying a coating agent to at least the first side of the resin substrate to form an oxygen barrier coating.

[0170] <Determination Method>

[0171] Using a white LED line light source, an arbitrary area of ​​36.6 mm square on the first surface of the resin substrate is illuminated at a distance of 100 mm and an incident angle of 83°. A monochrome line scan camera is used to capture transmitted light at a measurement angle of 90° to obtain an image. An analytical image of 3551 pixels × 5684 pixels (2.5 × 4.0 mm) is cropped from the captured image, and protrusions with a Feretta diameter of 8 μm or more in the analytical image are counted.

[0172] Embodiments of the barrier membrane of this disclosure are shown and described. Figure 4 This is a schematic cross-sectional view of the gas barrier membrane 101 according to Embodiment 2. For ease of explanation, Figure 4 The aspect ratio in the diagram differs from the actual aspect ratio. The gas barrier film 101 comprises: a resin substrate 120, a base layer 140, an inorganic oxide layer 150, and an oxygen barrier coating 130. It should be noted that either the base layer 140 or the inorganic oxide layer 150 may be absent. The base layer 140 is in contact with and stacked on the first surface 21 of the resin substrate 120, and the inorganic oxide layer 150 is stacked on the opposite surface of the base layer 140 to the surface in contact with the resin substrate 120. The inorganic oxide layer 150 is in contact with and stacked on the base layer 140, and the oxygen barrier coating 130 is in contact with and located on the opposite surface of the inorganic oxide layer 150 to the surface in contact with the base layer 140. It should be noted that, without the base layer 140, the inorganic oxide layer 150 is stacked on the first surface 21 of the resin substrate 120. In addition, without the inorganic oxide layer 150, the oxygen barrier coating 130 is laminated on the substrate layer 140.

[0173] <Resin substrate>

[0174] The resin substrate 120 has two or more resin layers, including a base layer 25. In this embodiment, it has a base layer 25 and a surface layer 23 located on one surface of the base layer 25. The surface layer 23 constitutes a first surface 21 of the resin substrate 120. The resin substrate 120 contains resin, and each layer constituting the resin substrate 120, including the surface layer 23 and the base layer 25, also contains resin.

[0175] The base layer 25 modifies the mechanical, chemical, thermal, and optical properties of the resin substrate 120. Mechanical properties include rigidity, elongation, stiffness, tear strength, impact strength, puncture strength, and pinhole resistance. Chemical properties include water vapor barrier properties, gas barrier properties, aroma retention, chemical resistance, and oil resistance. Thermal properties include melting point / glass transition temperature, heat resistance temperature, cold resistance temperature, and thermal shrinkage rate. Optical properties include transparency and gloss.

[0176] From the viewpoint of ease of acquisition and water vapor barrier properties, polyolefin resins are preferred as the raw material for the base layer 25. Examples of polyolefin resins include polyethylene, polypropylene, and polybutene. Polypropylene can be any of a homopolymer, a random copolymer, or a block copolymer. A homopolymer is polypropylene composed solely of propylene monomers. A random copolymer is a homogeneous phase of polypropylene formed by random copolymerization of propylene as the main monomer with a comonomer of a different type than propylene. A block copolymer is a heterogeneous phase of polypropylene formed by block copolymerization of propylene as the main monomer with the aforementioned comonomers, or by gel polymerization. Any one of these polyolefin resins can be used alone, or two or more can be used in combination.

[0177] The base layer 25 may also contain additives. These additives can be appropriately selected from a variety of known additives. Examples of additives include: fillers, anti-blocking agents (AB agents), heat stabilizers, weather stabilizers, ultraviolet absorbers, lubricants, slip agents, nucleating agents, antistatic agents, antifogging agents, pigments, and dyes. Any one of these additives may be used alone, or in combination of two or more. The content of additives in the base layer 25 can be appropriately adjusted without impairing the effects of this disclosure.

[0178] The base layer 25 can be a single-layer structure or a multi-layer structure. The thickness of the base layer 25 can be, for example, 3–200 μm or 6–30 μm.

[0179] The surface layer 23 is composed of a polyolefin copolymer resin. Examples of polyolefin copolymer resins include: ethylene-propylene copolymers, ethylene-1-butene copolymers, propylene-1-butene copolymers, propylene-pentene copolymers, ethylene-propylene-1-butene copolymers, ethylene-acrylic acid copolymers, ionomers of ethylene-acrylic acid copolymers crosslinked with metal ions, and propylene-acrylic acid copolymers, each of which can be a random copolymer or a block copolymer. Any one of these resins can be used alone, or two or more can be mixed. Because the surface layer 23 is composed of a polyolefin copolymer resin, it exhibits good adhesion to any of the base layer 140, the inorganic oxide layer 150, and the oxygen barrier coating 130 laminated on the resin substrate 120.

[0180] Surface layer 23 may contain additives. These additives can be appropriately selected from a variety of known additives. Examples of additives include: anti-blocking agents (AB agents), heat stabilizers, weather stabilizers, ultraviolet absorbers, lubricants, slip agents, nucleating agents, antistatic agents, antifogging agents, pigments, and dyes. Any one of these additives may be used alone, or in combination of two or more. The content of additives in surface layer 23 may be appropriately adjusted without impairing the effects of this disclosure.

[0181] When the surface layer 23 contains an AB agent, protrusions from the AB agent are formed on the first surface 21 of the resin substrate 120. These protrusions prevent the films from sticking together, thereby improving the processability of the film material during winding, unwinding, and conveying. In particular, the average particle size and amount of the AB agent affect the size and number of protrusions on the first surface 21, and therefore it is preferable to adjust them so that the number of protrusions with a Freret diameter of 8 μm or more in the measurement method described later is 20 per mm. 2 the following.

[0182] AB agents are solid particles, and can include organic and inorganic particles. Examples of organic particles include polymethyl methacrylate (PMMA) particles, polystyrene particles, and polyamide particles. These organic particles can be obtained, for example, through emulsion polymerization or suspension polymerization. Examples of inorganic particles include silica particles, zeolite, talc, kaolin, and feldspar. Any one of these AB agents can be used alone, or in combination of two or more. Among organic AB agents, PMMA particles are preferred, and among inorganic AB agents, silica particles are preferred.

[0183] The average particle size of the AB agent is preferably 0.1 μm or more and 5 μm or less. From the viewpoint that the gas barrier membrane 101 has both anti-blocking and gas barrier properties, the average particle size of the AB agent is particularly preferably 1 μm or more and 4 μm or less. The average particle size of the AB agent can be determined by the Coulter method.

[0184] The amount of AB agent added relative to the total mass of surface layer 23 is preferably 0.05 to 0.4% by mass. Specifically, the amount of AB agent added to surface layer 23 is calculated by the following formula.

[0185] The amount of AB agent added [mass %] = {(i) / 100} × {(ii) / 100} × 100

[0186] In the formula, (i) refers to the concentration (mass %) of the AB agent in the masterbatch resin chips formed by melt extrusion after adding the AB agent to the resin and stirring, then mixing it in an extruder. (ii) represents the concentration (mass %) of the AB agent-containing masterbatch resin chips relative to the total mass of the resin particles constituting the surface layer 23 when the masterbatch resin chips containing the AB agent are mixed with resins without the AB agent. It should be noted that the amount of AB agent added to the base layer 25 is also the same, preferably 0.05 to 0.4% by mass relative to the total mass of the base layer 25, and the amount can be calculated using the above formula.

[0187] The thickness of the surface layer 23 can be, for example, 0.1 to 10 μm, or more specifically, 0.5 to 5.0 μm.

[0188] Preferably, the resin substrate 120 includes at least a surface layer 23 and a base layer 25, and is a co-extruded film. The resin substrate 120 can be a stretched film or an unstretched film.

[0189] The resin substrate 120 preferably has a biaxially oriented polypropylene film. Biaxially oriented polypropylene films have particularly excellent water vapor barrier properties, thus improving the water vapor barrier properties of the gas barrier film 101. The biaxially oriented polypropylene film can be obtained by processing at least one of homopolymers, random copolymers, block copolymers, etc., into a film form. The biaxially oriented polypropylene film is preferably a co-extruded film.

[0190] The base layer 25 can be composed of a biaxially oriented polypropylene film, or it can be composed of a biaxially oriented polypropylene film laminated with other resin films. Other resin films include, for example, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyolefin resin films such as polyethylene, polystyrene films, polyamide films such as nylon, polycarbonate films, polyacrylonitrile films, and engineering plastic films such as polyimide films.

[0191] The thickness of the resin substrate 120 is not particularly limited, and is appropriately selected based on price and application, taking into account its suitability as a packaging material and its suitability for lamination with other coatings. Practically, the thickness of the resin substrate 120 is preferably 3 μm to 200 μm, more preferably 5 μm to 120 μm, and even more preferably 6 μm to 30 μm.

[0192] The first surface 21 of the resin substrate 120 can be subjected to at least one treatment selected from the group consisting of chemical treatment, solvent treatment, corona treatment, plasma treatment and ozone treatment.

[0193] When protrusions caused by the AB agent are formed on the first surface 21 of the resin substrate 120, film adhesion can be prevented. Conversely, in large protrusions, membrane defects that become pathways for gas permeation are easily generated in the base layer 140, inorganic oxide layer 150, and oxygen barrier coating 130 formed thereon, thereby potentially reducing the oxygen barrier properties of the gas barrier film 101. However, the first surface 21 of the resin substrate 120 of the gas barrier film 101 of this disclosure is characterized by having 20 protrusions / mm with a Ferrette diameter of 8 μm or more, as measured by the measurement method shown below. 2 The following conditions make it difficult for film defects to occur. More preferably, the number of protrusions with a Freette diameter of 8 μm or more on the first surface 21 of the resin substrate 120 is 17 per mm. 2 The following is preferred: protrusions with a Feretta diameter of 8 μm or more, preferably 15 per mm. 2 Below, the number of Ferret protrusions with a diameter of 8 μm or more can also be 0 per mm. 2 For protrusions with a Fehle diameter of 8 μm or more, many have a height exceeding 1 μm from the flat portion of the first surface 21 to the protrusion apex, which easily leads to membrane defects in the oxygen barrier coating. Therefore, when the number of protrusions with a Fehle diameter of 8 μm or more is 20 / mm... 2 In this case, film defects are less likely to occur in the substrate layer 140, inorganic oxide layer 150, and oxygen barrier coating 130, thus making the oxygen barrier properties of the gas barrier film 101 even better. It should be noted that the protrusions formed on the first surface 21 of the resin substrate 120 may originate from the AB agent or be caused by other factors, without particular limitation. In this specification, the number of protrusions on the first surface 21 of the resin substrate 120 is a value determined by the following measurement method.

[0194] <Determination Method>

[0195] A white LED line light source was used to illuminate an arbitrary area of ​​the resin substrate 120 (36.6 mm square) from the side opposite the first surface 21 (i.e., the second surface 22) at a distance of 100 mm and an incident angle of 83°. A monochrome line scan camera was used to capture transmitted light at a measurement angle of 90° to obtain an image. An analytical image of 3551 pixels × 5684 pixels (2.5 × 4.0 mm) was cropped from the acquired image. For the cropped analytical image, image analysis software was used to extract and count the number of protrusions with a Feretta diameter of 8 μm or more, converting them to a per mm value. 2 This yields the number of protrusions with a diameter of 8 μm or more, thus obtaining the number of protrusions.

[0196] The following describes a method for measuring the number of protrusions on the first surface 21 of the resin substrate 120, with reference to the accompanying drawings. First, the measuring apparatus will be described.

[0197] (Measuring apparatus)

[0198] like Figure 5 As shown, the measuring device 15 for determining the number of protrusions on the first surface 21 of the resin substrate 120 includes a sample holder 2, a light source 4, and a monochrome line scan camera 7. The sample holder 2 is mounted on a conveying device 16 and can move horizontally. A perforation 3 is formed in the center of the sample holder 2. The light source 4 is located below the sample holder 2 and positioned at a distance of 100 mm from the light source, and is connected to a light source control device 6. The monochrome line scan camera 7 is located above the sample holder 2, and a macro lens 8 is mounted on the monochrome line scan camera 7. An image processing device 9 is connected to the monochrome line scan camera 7. A conveying control unit 17 is connected to the image processing device 9. The conveying control unit 17 is connected to the conveying device 16.

[0199] The sample holder 2 is not particularly limited as long as it is flat and horizontal, and any known holder can be used. As the light source 4, a white LED line light source for visible light is preferred.

[0200] The monochrome line scan camera 7 preferably uses a camera with 16384 pixels and a sensor size of 3.52 μm per pixel. The monochrome line scan camera 7 is preferably controlled by an image processing device 9 via a camera connection or a standard interface such as USB. The image processing device 9 consists, for example, a computer with frame images connected to the monochrome line scan camera 7 installed, and image processing software that controls the frame images. Computers with frame images installed and image processing software that controls the frame images are widely distributed or commercially available, and can be used as the image processing device 9. For example, the public domain software "ImageJ" developed by the National Institutes of Health (NIH) can be cited as image processing software.

[0201] The conveying device 16 preferably uses a single-axis stage driven by a stepper motor or the like. The conveying device 16 controls the conveying speed, conveying start, conveying stop, etc., through the conveying control unit 17.

[0202] (Sample preparation)

[0203] Next, the method for determining the number of protrusions on the first surface of the resin substrate 120 will be explained. For example... Figure 5As shown, firstly, the first surface 21 of the resin substrate 120 is oriented towards the monochrome line scan camera 7, and the resin substrate 120 is fixed to the sample holder 2 in a manner that does not create a height difference within the surface. When fixing the resin substrate 120, it is preferable to use OPP tape or masking tape to fix the ends of the resin substrate 120. The resin substrate 120 is fixed to the sample holder 2 in a manner that aligns the image measurement position 18 of the resin substrate 120 with the punch 3.

[0204] (Image acquisition)

[0205] Next, white LED linear light is incident from light source 4. The amount of light from light source 4 can be adjusted by light source control device 6. Preferably, the amount of incident light L1 is adjusted using light source control device 6 so that the amount of light at image measurement position 18 is 442 lux. The incident light L1 from light source 4 has an incident angle 13 of 83° relative to the first surface 21, and is offset by 7° from the vertical direction. Monochrome line scan camera 7 is set at a position with a measurement angle 19 of 90° relative to the first surface 21. The transmitted light L2 passing through image measurement position 18 is captured by monochrome line scan camera 7 through macro lens 8. At this time, the magnification of macro lens 8 is set to 5x, the F-value is set to 2.8, and the resolution is set to 0.704μm. The measurement range of monochrome line scan camera 7 at image measurement position 18 is set to a 36.6mm square area, and the effective illumination range of light source 4 is set to an area greater than 36.6mm square.

[0206] The measurement range of transmitted light L2 is a 36.6 mm square area of ​​the first surface 21. The conveying device 16 is moved so that the measurement range is the aforementioned area. If the conveying device 16 is a stepper motor or the like, a pulse signal indicating the conveying speed is input to the image processing device 9. Preferably, the conveying speed of the conveying device 16 is set to be equal to the product of the spatial resolution and the capture frequency. The spatial resolution is determined based on the sensor size (3.52 μm) of the monochrome line scan camera 7 and the magnification (5x) of the macro lens 8. The capture frequency is the capture frequency of one line of the monochrome line scan camera 7. With the conveying speed set to be equal to the product of the spatial resolution and the capture frequency, the resin substrate 120 is continuously conveyed at the image measurement position 18 of the monochrome line scan camera 7. At the image measurement position 18, an image of the first surface 21 of the resin substrate 120 is measured and captured by the monochrome line scan camera 7.

[0207] The exposure time of the monochrome line scan camera 7 is set to 80 μs. The period of the capture frequency is set to be longer than the exposure time. The resin substrate 120 is transported, and images with more than 5684 pixels are acquired in the transport direction of the resin substrate 120.

[0208] (Image Analysis)

[0209] From the acquired images, a central 3551 pixel and a 5684 pixel along the transport direction, corresponding to the sensor arrangement direction of the monochrome line scan camera 7 (perpendicular to the transport direction of the resin substrate 120), are cropped out as images for analysis. In the transport direction, more than 5684 pixels can also be cropped to expand the measurement range. The cropped images for analysis are then analyzed using image analysis software.

[0210] Figure 6 This demonstrates the principle by which the system can detect minute protrusions or depressions on the surface of a resin substrate 120. In a linear array camera, when the incident angle θ2 is less than the measurement angle θ1, the upper part of the image at the protrusion is bright and the lower part is dark, thus allowing for three-dimensional visualization. At the depression, the upper and lower parts are reversed. This is presumably due to refraction approximately similar to that of a spherical lens. Utilizing this tendency, bright and dark particles are separated from the analytical image based on brightness, size, and roundness, respectively. Binarization is then performed, and the particles with the bright upper part and dark lower part are extracted as protrusions. The Freette diameter data of the extracted particles are then obtained. Figure 7 An image of the first surface 21 of the resin substrate 120 of the embodiment is shown, along with an analytical image of the protruding portion extracted using the algorithm described above. Based on the extracted Ferrette diameter data, the number of particles with a Ferrette diameter of 8 μm or more within the analytical image is counted and converted to a per mm value. 2 The value following the number of areas is used as the number of protrusions.

[0211] <Basal layer>

[0212] A base layer 140 is disposed between the resin substrate 120 and the inorganic oxide layer 150 or the oxygen barrier coating 130. The base layer 140 is a layer containing organic polymers as the main component, and is also called a primer layer. By providing the base layer 140, the film-forming properties and adhesion strength of the inorganic oxide layer 150 or the oxygen barrier coating 130 can be improved.

[0213] The content of organic polymer in the substrate 140 can be, for example, 70% by mass or more, or 80% by mass or more. Examples of organic polymers include: polyacrylic acid resin, polyester resin, polycarbonate resin, polyurethane resin, polyamide resin, polyolefin resin, polyimide resin, melamine resin, phenolic resin, etc. When considering the adhesion strength and hot water resistance between the resin substrate 120 and the inorganic oxide layer 150 or the oxygen barrier coating 130, it is preferable to contain at least one of polyacrylic acid resin, polyol resin, polyurethane resin, polyamide resin, or reaction products of these organic polymers. Additionally, the substrate 140 may also contain a silane coupling agent, an organotitanate, or a modified silicone oil.

[0214] As an organic polymer, the following are further preferred examples: organic polymers with urethane bonds formed by reacting polyols having two or more hydroxyl groups at the polymer terminal with isocyanate compounds; and / or organic polymers containing reaction products of polyols having two or more hydroxyl groups at the polymer terminal with organosilane compounds such as silane coupling agents or their hydrolysates.

[0215] Examples of polyols include at least one selected from acrylic polyols, polyvinyl acetals, polystyrene polyols, and polyurethane polyols. Acrylic polyols can be obtained by polymerizing acrylic derivative monomers or by copolymerizing acrylic derivative monomers with other monomers. Examples of acrylic derivative monomers include ethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Examples of monomers copolymerized with acrylic derivative monomers include styrene.

[0216] Isocyanate compounds enhance the adhesion between the resin substrate 120 and the inorganic oxide layer 150 or the oxygen barrier coating 130 by reacting with polyols to form urethane bonds. In other words, the isocyanate compound acts as a crosslinking agent or curing agent. Examples of isocyanate compounds include, for instance, aromatic monomers such as toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), aliphatic monomers such as xylene diisocyanate (XDI), hexamethylene diisocyanate (HMDI), and isophorone diisocyanate (IPDI), their polymers, and their derivatives. The aforementioned isocyanate compounds can be used alone or in combination of two or more.

[0217] Examples of silane coupling agents include, for example, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, propylene oxide propyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropylmethyldimethoxysilane. Organosilane compounds can also be hydrolysates of these silane coupling agents. Organosilane compounds can include one of the above-mentioned silane coupling agents and their hydrolysates, or they can combine two or more of them.

[0218] A mixture can be prepared by mixing the above components in an organic solvent in any proportion, and the prepared mixture can be used to form a base layer 140 on the first surface 21 of the resin substrate 120. The mixture may also contain, for example, curing accelerators such as tertiary amines, imidazole derivatives, metal salt compounds of carboxylic acids, quaternary ammonium salts, and quaternary phosphonium salts; antioxidants such as phenolic, sulfur-based, and phosphite-based agents; leveling agents, flow regulators, catalysts, crosslinking reaction promoters, and fillers.

[0219] The mixture can be applied to the resin substrate 120 using known printing methods such as offset printing, gravure printing, or screen printing; or known coating methods such as roller coating, air knife coating, or gravure coating. After coating, the base layer 140 can be formed, for example, by heating to 50–200°C and drying and / or curing.

[0220] There is no particular limitation on the thickness of the substrate 140, for example, it can be 0.005 to 5 μm. The thickness can be adjusted according to the application or the desired properties. The thickness of the substrate 140 is preferably 0.01 to 1 μm, more preferably 0.01 to 0.5 μm. If the thickness of the substrate 140 is 0.01 μm or more, sufficient adhesion strength can be obtained between the resin substrate 120 and the inorganic oxide layer 150 or the oxygen barrier coating 130, thereby achieving good oxygen barrier properties. If the thickness of the substrate 140 is 1 μm or less, it is easy to form a uniform coating surface, and the drying load and manufacturing cost can be suppressed.

[0221] <Inorganic oxide layer>

[0222] Examples of inorganic oxide layers 150 include aluminum oxide, silicon oxide, magnesium oxide, titanium oxide, tin oxide, zinc oxide, and indium oxide. Aluminum oxide and silicon oxide are particularly preferred due to their excellent manufacturability and superior oxygen and water vapor barrier properties under heat and humid conditions. It should be noted that the inorganic oxide layer 150 may contain one of these materials alone or in combination with two or more. The thickness of the inorganic oxide layer 150 is preferably 1–200 nm. A thickness of 1 nm or more provides excellent oxygen and water vapor barrier properties, while a thickness of 200 nm or less reduces manufacturing costs and minimizes the risk of cracking due to bending or stretching, thus suppressing degradation of barrier properties. The inorganic oxide layer 150 can be formed using known film-forming methods such as vacuum evaporation, sputtering, ion plating, or plasma vapor deposition (CVD).

[0223] <Oxygen Barrier Coating>

[0224] It is known that the oxygen barrier coating 130 can be an oxygen barrier coating formed by a wet coating method. The oxygen barrier coating 130 can be obtained by forming a coating film composed of a coating agent on a substrate layer 140 or an inorganic oxide layer 150 by a wet coating method, and then drying the coating film. It should be noted that the coating film is a wet film, and the coating film is a dry film.

[0225] As the oxygen barrier coating 130, it is preferably a coating containing at least one of a metal alkoxide and its hydrolysate, and its reaction product, and a water-soluble polymer (organic-inorganic composite coating). Furthermore, it is even more preferred to be a coating containing at least one of a silane coupling agent and its hydrolysate.

[0226] Metal alkoxides and their hydrolysates contained in organic-inorganic composite membranes include, for example, tetraethoxysilane [Si(OC2H5)4] and triisopropoxyaluminum [Al(OC3H7)3], which are derived from the general formula M(OR). n The compounds and their hydrolysates represented may contain one of these compounds alone or in combination of two or more.

[0227] In organic-inorganic composite membranes, the total content of at least one of the metal alkoxides and their hydrolysates, and their reaction products, is, for example, 40–70% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the total content of at least one of the metal alkoxides and their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 50% by mass. From the same viewpoint, the upper limit of the total content of at least one of the metal alkoxides and their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 65% by mass.

[0228] There are no particular limitations on the water-soluble polymers contained in the organic-inorganic composite membrane. Examples include: polyvinyl alcohol-based polymers; polysaccharides such as starch, methylcellulose, and carboxymethylcellulose; and acrylic polyol-based polymers. From the viewpoint of further improving oxygen barrier properties, polyvinyl alcohol-based polymers are preferred. The number-average molecular weight of the water-soluble polymers is, for example, 40,000 to 180,000.

[0229] Water-soluble polymers based on polyvinyl alcohol can be obtained, for example, by saponifying (including partially saponifying) polyvinyl acetate. These water-soluble polymers may contain tens of percent or only a few percent of acetic acid groups.

[0230] The content of water-soluble polymers in organic-inorganic composite membranes is, for example, 15–50% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the content of water-soluble polymers in organic-inorganic composite membranes can be 20% by mass. From the viewpoint of further reducing oxygen permeability, the upper limit of the content of water-soluble polymers in organic-inorganic composite membranes can be 45% by mass.

[0231] Silane coupling agents and their hydrolysates contained in organic-inorganic composite membranes can be categorized as having organic functional groups. Examples of such silane coupling agents and their hydrolysates include: ethyltrimethoxysilane, vinyltrimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-chloropropyltrimethoxysilane, glycidoxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and their hydrolysates. These can be contained individually or in combination of two or more.

[0232] At least one of the silane coupling agent and its hydrolysate is preferably a silane coupling agent having an epoxy group as an organic functional group. Examples of epoxy-containing silane coupling agents include γ-epoxypropoxypropyltrimethoxysilane and β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. Epoxy-containing silane coupling agents and their hydrolysates may also have organic functional groups different from the epoxy group, such as vinyl, amino, methacrylate, or urea groups.

[0233] Silane coupling agents with organic functional groups and their hydrolysates can further improve the oxygen barrier properties of the oxygen barrier coating 130 and its adhesion to the substrate layer 140 or the inorganic oxide layer 150 through the interaction of their organic functional groups with the hydroxyl groups of water-soluble polymers. In particular, by allowing the epoxy groups of the silane coupling agent and its hydrolysates to interact with the hydroxyl groups of polyvinyl alcohol, an oxygen barrier coating 130 with particularly excellent oxygen barrier properties and adhesion to the substrate layer 140 or the inorganic oxide layer 150 can be formed.

[0234] In organic-inorganic composite membranes, the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products is, for example, 1 to 15% by mass. From the viewpoint of further reducing oxygen permeability, the lower limit of the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 2% by mass. From the same viewpoint, the upper limit of the total content of at least one of silane coupling agents, their hydrolysates, and their reaction products in organic-inorganic composite membranes can be 12% by mass.

[0235] Organic-inorganic composite membranes may also contain crystalline inorganic layered compounds with a layered structure. Examples of inorganic layered compounds include clay minerals such as those from the kaolinite, montmorillonite, or mica groups. These can be used alone or in combination of two or more. The particle size of the inorganic layered compounds is, for example, 0.1–10 μm. The aspect ratio of the inorganic layered compounds is, for example, 50–5000.

[0236] As inorganic layered compounds, by introducing water-soluble polymers into the interlayer spaces of the layered structure, a coating with excellent oxygen barrier properties and strong adhesion can be formed. Therefore, clay minerals of the montmorillonite group are preferred. Specific examples of clay minerals of the montmorillonite group include montmorillonite, hydropyrite, as well as bentonite and water-swellable synthetic mica.

[0237] Another preferred example of the oxygen barrier coating 130 is a coating containing a polycarboxylic acid polyvalent metal salt (polycarboxylic acid polyvalent metal salt coating), which is a reaction product of the carboxyl group of a polycarboxylic acid polymer (A) and a polyvalent metal compound (B). In this case, the polycarboxylic acid polyvalent metal salt coating can be formed by coating a coating agent mixed with polycarboxylic acid polymer (A) and polyvalent metal compound (B) and heating and drying; or it can be formed by coating a coating agent with polycarboxylic acid polymer (A) as the main component and drying to form coating A, then coating a coating agent with polyvalent metal compound (B) as the main component on it and drying to form coating B, and then causing a crosslinking reaction between the A / B layers to form the polycarboxylic acid polyvalent metal salt coating.

[0238] [Polycarboxylate polymer (A)]

[0239] Polycarboxylate polymers are polymers with two or more carboxyl groups within their molecules. Examples of polycarboxylate polymers include (co)polymers of olefinically unsaturated carboxylic acids; copolymers of olefinically unsaturated carboxylic acids with other olefinically unsaturated monomers; and acidic polysaccharides containing carboxyl groups, such as alginate, carboxymethyl cellulose, and pectin. Examples of olefinically unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of olefinically unsaturated monomers that can copolymerize with olefinically unsaturated carboxylic acids include: ethylene, propylene, vinyl acetate, and other saturated carboxylic acid vinyl esters; alkyl acrylates, alkyl methacrylates, alkyl itaconic acid esters, vinyl chloride, vinylidene chloride, styrene, acrylamide, and acrylonitrile. These polycarboxylate polymers can be used individually or in mixtures of two or more.

[0240] From the viewpoint of the gas barrier properties of the resulting gas-barrier membrane, the polymers described above preferably include constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, itaconic acid, fumaric acid, and crotonic acid. Polymers particularly preferred are those comprising constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid. In this polymer, the proportion of constituent units derived from at least one polymerizable monomer selected from the group consisting of acrylic acid, maleic acid, methacrylic acid, and itaconic acid is preferably 80 mol% or more, more preferably 90 mol% or more (wherein the total of all constituent units constituting the polymer is set to 100 mol%). This polymer can be a homopolymer or a copolymer. When the polymer is a copolymer containing constituent units other than those described above, examples of such other constituent units include constituent units derived from olefinically unsaturated monomers that can copolymerize with the aforementioned olefinically unsaturated carboxylic acids.

[0241] The number-average molecular weight of the polycarboxylate polymer is preferably in the range of 2,000 to 10,000,000, more preferably 5,000 to 1,000,000. When the number-average molecular weight is less than 2,000, the resulting gas-barrier film cannot achieve sufficient water resistance, and sometimes the gas barrier properties and transparency deteriorate due to moisture, or sometimes whitening occurs. On the other hand, when the number-average molecular weight exceeds 10,000,000, the viscosity of the coating agent used to form the oxygen barrier coating 130 becomes high, which may impair the coatability. It should be noted that the above-mentioned number-average molecular weight is the number-average molecular weight converted from polystyrene obtained by gel permeation chromatography (GPC).

[0242] In the case of coating an agent with polycarboxylate polymer (A) as the main component and drying it to form film A, and then forming film B, a portion of the carboxyl groups of the polycarboxylate polymer can be neutralized beforehand with an alkaline compound. By pre-neutralizing a portion of the carboxyl groups present in the polycarboxylate polymer, the water resistance and heat resistance of film A can be further improved. Preferably, the alkaline compound is at least one selected from the group consisting of polyvalent metal compounds, monovalent metal compounds, and ammonia. As the polyvalent metal compound, compounds exemplified in the description of polyvalent metal compound (B) described later can be used. Examples of monovalent metal compounds include sodium hydroxide and potassium hydroxide.

[0243] Various additives can be added to coating agents with polycarboxylate polymers (A) as the main component. Within the range that does not impair the barrier properties, crosslinking agents, curing agents, leveling agents, defoamers, antiblocking agents, antistatic agents, dispersants, surfactants, softeners, stabilizers, film-forming agents, thickeners, etc. can be added.

[0244] The solvent used in coating agents with polycarboxylate polymers (A) as the main component is preferably an aqueous medium. Examples of aqueous mediums include water, water-soluble or hydrophilic organic solvents, or mixtures thereof. Aqueous mediums typically contain water or have water as the main component. The water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more. Examples of water-soluble or hydrophilic organic solvents include, for example: alcohols such as methanol, ethanol, and isopropanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; cellosols; carbitols; and nitrile compounds such as acetonitrile.

[0245] [Polyvalent metal compound (B)]

[0246] There are no particular limitations on the type of polyvalent metal compound that can react with the carboxyl groups of polycarboxylate polymers to form polycarboxylate polyvalent metal salts; examples include zinc oxide particles, magnesium oxide particles, magnesium methoxide, copper oxide, and calcium carbonate. These can be used alone or in combination. From the viewpoint of oxygen barrier properties in oxygen barrier coatings, zinc oxide is preferred.

[0247] Zinc oxide is an inorganic material with ultraviolet absorption properties. There is no particular limitation on the average particle size of zinc oxide particles, but from the viewpoints of gas barrier properties, transparency, and coating suitability, the average particle size is preferably 5 μm or less, more preferably 1 μm or less, and particularly preferably 0.1 μm or less.

[0248] When a coating agent with a polyvalent metal compound (B) as the main component is applied and dried to form a B film, various additives other than zinc oxide particles may be included as needed, without impairing the effects of this disclosure. Examples of such additives include: resins that can be dissolved or dispersed in the solvent used in the coating agent, dispersants that can be dissolved or dispersed in the solvent, surfactants, softeners, stabilizers, film-forming agents, thickeners, etc.

[0249] In the above-mentioned applications, it is preferable to include a resin that can be dissolved or dispersed in a solvent used in the coating agent. This improves the coatability and film-forming properties of the coating agent. Examples of such resins include alkyd resins, melamine resins, acrylic resins, urethane resins, polyester resins, phenolic resins, amino resins, fluororesins, epoxy resins, and isocyanate resins.

[0250] Furthermore, it is preferable to contain a dispersant that can be dissolved or dispersed in the solvent used in the coating agent. This improves the dispersibility of the polyvalent metal compound. Anionic or nonionic surfactants can be used as dispersants. Examples of such surfactants include: (poly)carboxylates, alkyl sulfates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, aromatic phosphates, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene alkyl esters, alkyl aryl sulfates, polyoxyethylene alkyl phosphates, sorbitol alkyl esters, glycerol fatty acid esters, sorbitol fatty acid esters, sucrose fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene sorbitol alkyl esters, polyoxyethylene alkyl allyl ethers, polyoxyethylene derivatives, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, and various other surfactants. These surfactants can be used alone or in mixtures of two or more.

[0251] When the coating agent, whose main component is a polyvalent metal compound (B), contains additives, the mass ratio of the polyvalent metal compound to the additive (polyvalent metal compound: additive) is preferably in the range of 30:70 to 99:1, more preferably in the range of 50:50 to 98:2.

[0252] Solvents used in coating agents whose main component is a polyvalent metal compound (B) include, for example, water, methanol, ethanol, isopropanol, n-propanol, n-butanol, n-pentanol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents can be used individually or in mixtures of two or more. From the viewpoint of coatability, methanol, ethanol, isopropanol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferred. Furthermore, from the viewpoint of manufacturability, methanol, ethanol, isopropanol, and water are preferred.

[0253] In the case of coating a mixture of polycarboxylate polymer (A) and polyvalent metal compound (B) to form a polycarboxylate polyvalent metal salt film, the polycarboxylate polymer (A), the polyvalent metal compound (B), water or alcohol as a solvent, a resin or dispersant soluble or dispersed in the solvent, and additives as needed are mixed as a coating agent, and the coating is performed using a known coating method and then dried to form a polycarboxylate polyvalent metal salt film. Examples of coating methods include casting, dipping, roller coating, gravure coating, screen printing, reverse coating, spraying, overcoating, die coating, metering bar coating, chamber air knife combined coating, and curtain coating.

[0254] The thickness of the oxygen barrier coating 130 is set according to the desired oxygen barrier performance, and can be, for example, 0.05 to 5 μm. Preferably, the thickness of the oxygen barrier coating 130 is 0.05 to 1 μm, more preferably 0.1 to 0.5 μm. If the thickness of the oxygen barrier coating 130 is 0.05 μm or more, sufficient oxygen barrier performance is easily obtained. If the thickness of the oxygen barrier coating 130 is 1 μm or less, a uniform coating surface is easily formed, and drying load and manufacturing costs can be suppressed.

[0255] In the oxygen barrier film 130, the gas barrier film having the above-mentioned organic-inorganic composite film or the above-mentioned polycarboxylate polyvalent metal salt film can exhibit excellent oxygen barrier properties even after boiling or sterilization treatment. After lamination with the sealant film, even as a packaging material for boiling / sterilization treatment, it has sufficient sealing strength and sealing strength. In addition, it has the following advantages: transparency not found in metal foil or metal vapor-deposited film, excellent bending and tensile strength, and no risk of generating harmful substances such as dioxins.

[0256] [Manufacturing method of gas barrier membrane]

[0257] The gas barrier film 101 can be manufactured by forming either a base layer 140 or an inorganic oxide layer 150, or both, on a first surface 21 of a resin substrate 120, and then forming an oxygen barrier coating 130 on the base layer 140 or the inorganic oxide layer 150. The manufacturing method of the gas barrier film 101 disclosed herein includes, for example, a sorting step, a base layer forming step, an inorganic oxide layer forming step, and an oxygen barrier coating forming step.

[0258] As a sorting process, for example, the following can be listed: 20 protrusions with a surface diameter of 8μm or more per mm. 2 The following resin substrate raw materials are sorted to form resin substrate 120. The number of protrusions on the surface of the resin substrate raw materials is determined by the same method as the method for determining the number of protrusions on the first surface 21 of the resin substrate 120. As resin substrate 120, commercially available products or substrates manufactured by known methods can be used.

[0259] As a base layer forming process, the following steps can be listed as follows: applying a coating agent to at least the first surface 21 of the resin substrate 120 using a wet coating method to form a coating film, and drying the coating film (removing the solvent) to form the base layer 140. As a coating agent application method, known wet coating methods can be used. Examples of wet coating methods include: roller coating, gravure coating, reverse coating, mold coating, screen printing, and spray coating. As a method for drying the coating film composed of the coating agent, known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used. As drying conditions, for example, drying at 90°C for 10 seconds can be listed.

[0260] As an inorganic oxide layer formation process, the following process can be listed as an example: forming an inorganic oxide layer 150 on the first surface 21 of the resin substrate 120 or the base layer 140 by the above-mentioned vacuum evaporation method, sputtering method, ion plating method or plasma vapor deposition method (CVD).

[0261] As a step in forming an oxygen barrier coating, the following steps can be included: applying a coating agent to a substrate layer 140 or an inorganic oxide layer 150 using a wet coating method to form a coating film, and drying the coating film (removing the solvent) to form an oxygen barrier coating 130. Known wet coating methods can be used as the coating agent application method. Examples of wet coating methods include: roller coating, gravure coating, reverse coating, mold coating, screen printing, and spray coating. Known drying methods such as hot air drying, hot roller drying, and infrared irradiation can be used as the drying method. Examples of drying conditions include drying at 90°C for 10 seconds. The oxygen barrier coating 130 can be formed by applying and drying in a single step, or by repeatedly applying the same or different coating agents and drying them multiple times.

[0262] When the manufacturing method of the gas barrier film 101 disclosed herein includes a sorting step, it is possible to effectively apply a surface with 20 protrusions per mm that have a Feretta diameter of 8 μm or more. 2 The following resin substrate 120. Therefore, by having a sorting process, a gas barrier film with further improved oxygen barrier properties can be effectively manufactured. In addition, by having a sorting process, a gas barrier film 101 with good printability can also be effectively manufactured.

[0263] As needed, the gas barrier film 101 of this disclosure may further include a printing layer, a protective layer, a light-shielding layer, an adhesive layer, a heat-sealable heat-welding layer, and other functional layers. When the gas barrier film 101 of this disclosure has a heat-sealable heat-welding layer, this heat-welding layer is disposed on at least one outermost surface of the gas barrier film 101. Since the gas barrier film 101 has a heat-welding layer, the gas barrier film 101 can be sealed by heat sealing (e.g., for packaging, for caps). For example, known adhesives such as polyurethane-based, polyester-based, and polyether-based adhesives can be used, and the heat-welding layer can be laminated onto a laminate obtained by forming the base layer 140 or inorganic oxide layer 150 and oxygen barrier coating 130 of this embodiment on one or both sides of the resin substrate 120 using known dry lamination, extrusion lamination, or other methods.

[0264] <Effects>

[0265] In the gas barrier membrane 101 of this disclosure, the resin layer forming the first surface 21 is composed of a polyolefin copolymer resin, and on the first surface, there are 20 protrusions / mm with a Ferrette diameter of 8 μm or more as measured by the above-described method. 2 An oxygen barrier coating 130 is further laminated on the first surface 21 of the resin substrate 120, consisting of either a base layer 140 or an inorganic oxide layer 150, or both. In the gas barrier film 101 of this disclosure, the surface layer 23 is composed of a polyolefin copolymer resin, and has 20 protrusions / mm with a Ferrite diameter of 8 μm or more. 2 An oxygen barrier film 130 is formed on the resin substrate 120 via either a base layer 140 or an inorganic oxide layer 150, or both. This minimizes film defects caused by large protrusions on the substrate surface, resulting in better oxygen barrier properties and improved adhesion of the oxygen barrier film 130. Furthermore, in the gas barrier film 101 of this disclosure, it is unnecessary to unnecessarily increase the thickness of the base layer 140, the inorganic oxide layer 150, and the oxygen barrier film 130, thereby improving productivity and reducing material usage. Therefore, by using the gas barrier film 101 of this disclosure as a packaging material, it can possess sufficient lamination strength for packaging and improve the retention of contents quality at a low cost.

[0266] Example

[0267] The embodiments of this disclosure will be described in more detail below through examples and comparative examples. However, this disclosure is not limited to the following embodiments.

[0268] The materials used in the following examples are shown below.

[0269] [Materials Used]

[0270] <Resin substrate>

[0271] α1: Biaxially stretched polypropylene film (trade name: M-1, thickness 20μm, single-sided corona treatment, manufactured by Mitsui Chemicals Azusero Co., Ltd.).

[0272] α2: Biaxially stretched polypropylene film (trade name: ME-1, thickness 20μm, single-sided corona treatment, manufactured by Mitsui Chemicals Azusero Co., Ltd.).

[0273] α3: Biaxially stretched polypropylene film (trade name: TS18TI-TPN, thickness 18μm, single-sided corona treatment, manufactured by MaxSpeciality Films Limited).

[0274] α4: Biaxially stretched polypropylene film (trade name: P2111, thickness 20μm, single-sided corona treatment, manufactured by Toyobo Co., Ltd.).

[0275] α5: Biaxially stretched polypropylene film (trade name: P2171, thickness 20μm, single-sided corona treatment, manufactured by Toyobo Co., Ltd.).

[0276] α6: Biaxially stretched polypropylene film (trade name: P2102, thickness 20μm, single-sided corona treatment, manufactured by Toyobo Co., Ltd.).

[0277] α7: Biaxially stretched polypropylene film (trade name: P2161, thickness 20μm, single-sided corona treatment, manufactured by Toyobo Co., Ltd.).

[0278] α8: Biaxially stretched polypropylene film (trade name: VPH2011, thickness 20μm, single-sided corona treatment, average particle size of AB agent on the corona-treated side is 2μm, manufactured by AJPlast).

[0279] α9: Biaxially stretched polypropylene film (trade name: VPH2011, thickness 20μm, single-sided corona treatment, average particle size of AB agent on the corona-treated side is 4μm, manufactured by AJPlast).

[0280] α10: Biaxially stretched polypropylene film (trade name: PB210J, thickness 20μm, single-sided corona treatment, manufactured by "Futamura Chemical Co., Ltd").

[0281] α11: Polyethylene terephthalate film (trade name: P60, thickness 12μm, single-sided corona treatment, manufactured by Toray Industries Inc.).

[0282] α12: Polyethylene terephthalate film (trade name: E5102, thickness 12μm, single-sided corona treatment, manufactured by Toyobo Co., Ltd.).

[0283] α13: Polyethylene film (trade name: HD, thickness 40μm, single-sided corona treatment, manufactured by "Tamapori Co., Ltd").

[0284] α14: Polyethylene film (trade name: HS31, thickness 30μm, single-sided corona treatment, manufactured by "Tamapori Co., Ltd").

[0285] α15: Linear low-density polyethylene film (trade name: UB-3, thickness 40μm, single-sided corona treatment, manufactured by "Tamapori Co., Ltd").

[0286] α16: Polyethylene film (trade name: PE3K-H, thickness 25μm, single-sided corona treatment, manufactured by "Futamura Chemical Co., Ltd").

[0287] α17: Polyethylene film (trade name: PE3M, thickness 25μm, single-sided corona treatment, manufactured by "Futamura Chemical Co., Ltd").

[0288] α18: Linear low-density polyethylene film (trade name: LL-XHT, thickness 25μm, single-sided corona treatment, manufactured by "Futamura Chemical Co., Ltd.").

[0289] α19: Linear low-density polyethylene film (trade name: LL-RP2, thickness 25μm, single-sided corona treatment, manufactured by "Futamura Chemical Co., Ltd").

[0290] α20: Polyethylene film (25μm thick, single-sided corona treatment, manufactured by WINPAK Limited).

[0291] <Manufacturing Example 1>

[0292] Using "Acrylic CL-1000" (manufactured by DIC Co., Ltd.) as the acrylic polyol and "Coronato 2030" (manufactured by "Toso Co., Ltd.") as the TDI-type curing agent as the isocyanate compound, the acrylic polyol and the isocyanate compound were mixed at a solids weight ratio of 6:4, and a diluent (ethyl acetate) was used to prepare a mixture for substrate formation (solids content: 2% by mass).

[0293] <Manufacturing Example 2>

[0294] 58.9 parts by weight of distilled water were added to 20 parts by weight of an aqueous solution of polyacrylic acid (manufactured by Toa Synthetic Co., Ltd., "Aron A-10H", solids concentration 25% by weight) with a number average molecular weight of 200,000 for dilution. Then, 0.44 parts by weight of aminopropyltrimethoxysilane (manufactured by "APTMS Aldrich") was added, and the mixture was stirred to form a homogeneous solution, thereby preparing a coating agent with polycarboxylic acid polymer as the main component.

[0295] <Manufacturing Example 3>

[0296] 100 parts by weight of an aqueous dispersion of zinc oxide microparticles (ZE143 manufactured by Sumitomo Osaka Seminar) and 2 parts by weight of a curing agent, Liofol HAERTER UR 5889-21 (manufactured by Henkel), were mixed to prepare a coating agent with a polyvalent metal compound as the main component.

[0297] <Manufacturing Example 4>

[0298] An aqueous solution containing polyvinyl alcohol resin (PVA trade name: "Povar PVA-105", manufactured by Clare Co., Ltd., with a saponification degree of 98-99% and a polymerization degree of 500) was prepared, as well as aqueous solutions containing tetraoxyethylsilane (TEOS) and γ-epoxypropoxypropyltrimethoxysilane (GPTMS trade name: KBM-403 manufactured by Shin-Etsu Chemical Industry Co., Ltd.) hydrolyzed with 0.02 mol / L hydrochloric acid. The aqueous solutions were mixed in a weight ratio of PVA:TEOS:GPTMS of 40:50:10 as before hydrolysis. Further, a diluent was added to the mixed aqueous solution in a water:isopropanol mass ratio of 90:10 to prepare a coating agent (5% by mass) for forming an organic-inorganic composite film.

[0299] [Determination of the black area ratio of resin substrate]

[0300] For the corona-treated surfaces of resin substrates α1–12, the black area ratio was calculated based on the image acquisition and analysis conditions described above. The results are shown in Table 1. In the determination of the black area ratio, an Olympus Corporation OLS-4000 optical microscope with a 10x objective lens (MPFLN10) was used, and Scion ImageJ from Scion Corporation was used as the image analysis software.

[0301] [Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4]

[0302] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate as described in Table 1 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a gravure printing press, a coating agent mainly composed of polycarboxylate polymer prepared in Manufacturing Example 2 was coated onto the formed substrate layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. Further using a gravure printing press, a coating agent mainly composed of polyvalent metal compound prepared in Manufacturing Example 3 was coated onto the polycarboxylate polymer film to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm, and an oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 1-1 to 1-8 and Comparative Examples 1-1 to 1-4.

[0303] <Printability Evaluation>

[0304] Using a gravure printing press, ink (trade name: N920LPGT, manufactured by Toyo Ink Co., Ltd.) was printed on the oxygen barrier coating of each example of gas-barrier film at dot density levels of 5% to 50% (per 5% scale). The ink viscosity was 14 seconds ("Zencapsulation #3", 25°C). The printing speed was set to 150 m / min and the drying temperature to 50°C. The printed surface was observed using an optical microscope, and the number of defects was counted. In a 6 mm square area, if there were fewer than 5 defects, it was judged as ○; if there were 5 to 20 defects, it was judged as △; if there were 21 or more defects, it was judged as ×. The judgment results are shown in Table 1.

[0305] It should be noted that "slippage" refers to a state where the ink has poor adhesion to the film substrate, and some dots (half-dots) are not transferred. The fewer slippages there are, the better the printability of the highlights, up to a low dot density.

[0306] <Evaluation of oxygen and water vapor barrier properties after cooking>

[0307] Each example of a gas-barrier membrane was bonded to a CPP (polypropylene membrane) using an adhesive, thereby creating a gas-barrier laminated membrane for retort treatment consisting of a gas-barrier membrane / adhesive / CPP. The adhesive used was a two-component curing adhesive manufactured by Mitsui Chemicals Polyurethanes, "Takelac A620" (main agent) / "Takenet A65" (curing agent). The CPP used was a polypropylene membrane manufactured by Toray Film Processing, "Treffan ZK93KM" (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the membrane was configured such that the oxygen-barrier coating of the gas-barrier membrane was on the adhesive side.

[0308] The obtained gas-barrier laminated film was used to make an A5-sized bag with four sealed sides, and 150ml of tap water was filled as the contents. The bag was then subjected to heat sterilization treatment (boiling treatment) in hot water at 120°C for 30 minutes.

[0309] For the gas-barrier laminated membrane after cooking, the oxygen permeability (cm³) was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The measurement results are shown in Table 1.

[0310]

[0311] According to the results recorded in Table 1, the black area ratio of the gas barrier films in Examples 1-1 to 1-8 is less than 0.15%, and the oxygen permeability in an atmosphere of 30°C and 70% relative humidity is 2 cm⁻¹. 3 / (m 2 Below ·day·atm), good oxygen barrier properties were achieved.

[0312] On the other hand, the black area fraction of the gas barrier films in Comparative Examples 1-1 to 1-4 was 0.15% or more, and the oxygen permeability value exceeded 2 cm⁻¹. 3 / (m 2 The black area ratio (day atm) is relatively high, exceeding 0.15%, and the oxygen permeability increases. Compared with Examples 1-1 to 1-8, good oxygen barrier properties were not obtained.

[0313] According to the results recorded in Table 1, the printability of the gas barrier films of Examples 1-1 to 1-8 is “○” when the dot concentration is above 30%.

[0314] On the other hand, the printability of the barrier films of Comparative Examples 1-1 to 1-4 is “×” when the dot concentration is 30%.

[0315] This shows that printability is good when the black area ratio is below 0.15%.

[0316] [Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-4]

[0317] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate listed in Table 2 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated to form an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, the coating agent for forming an organic-inorganic composite coating prepared in Manufacturing Example 4 was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, forming an oxygen barrier coating composed of an organic-inorganic composite coating with a thickness of 0.3 μm, thus obtaining the gas barrier films of Examples 2-1 to 2-6 and Comparative Examples 2-1 to 2-4.

[0318] [Examples 2-7]

[0319] Instead of setting a base layer on the corona-treated surface of the resin substrate α8, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 2-7 is obtained in the same way as in Example 2-3.

[0320] <Printability Evaluation>

[0321] Using a gravure printing press, ink (trade name: N920LPGT, manufactured by Toyo Ink Co., Ltd.) was printed on the oxygen barrier coating of each example of gas-barrier film at dot density levels of 5% to 50% (per 5% scale). The ink viscosity was 14 seconds ("Zencapsulation #3", 25°C). The printing speed was set to 150 m / min and the drying temperature to 50°C. The printed surface was observed using an optical microscope, and the number of defects was counted. In a 6 mm square area, if there were fewer than 5 defects, it was judged as ○; if there were 5 to 20 defects, it was judged as △; if there were 21 or more defects, it was judged as ×. The judgment results are shown in Table 2.

[0322] It should be noted that "spotting" refers to a state where the ink has poor adhesion to the film substrate, and some dots (half-dots) are not transferred. The fewer spots there are, the better the printability of the highlights, up to a low dot density.

[0323] <Evaluation of oxygen and water vapor barrier properties after cooking>

[0324] Each example of a gas-barrier membrane was bonded to a CPP (polypropylene membrane) using an adhesive, thereby creating a gas-barrier laminated membrane for retort treatment consisting of a gas-barrier membrane / adhesive / CPP. The adhesive used was Mitsui Chemicals Polyurethane's two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent), and the CPP was Toray Film Processing's polypropylene membrane "Treffan ZK93KM" (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the membrane was configured so that the oxygen-barrier coating was on the adhesive side.

[0325] The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 150ml of tap water as the contents and then subjected to heat sterilization treatment (boiling treatment) in hot water at 120℃ for 30 minutes.

[0326] For the gas-barrier laminated membrane after cooking, the oxygen permeability (cm³) was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The measurement results are shown in Table 2.

[0327]

[0328] According to the results recorded in Table 2, the black area ratio of the gas barrier films in Examples 2-1 to 2-7 is less than 0.15%, and the oxygen permeability in an atmosphere of 30°C and 70% relative humidity is 3 cm⁻¹. 3 / (m 2 Below ·day·atm), good oxygen barrier properties were achieved.

[0329] On the other hand, the black area fraction of the gas barrier films in Comparative Examples 2-1 to 2-4 was 0.15% or more, and the oxygen permeability value exceeded 5 cm⁻¹. 3 / (m 2 (day atm), and because the black area ratio is higher than 0.15%, the oxygen permeability increases, and good oxygen barrier properties are not obtained compared with Examples 2-1 to 2-7.

[0330] According to the results recorded in Table 2, the printability of the barrier films of Examples 2-1 to 2-7 is “○” when the dot concentration is above 30%.

[0331] On the other hand, the printability of the barrier films of Comparative Examples 2-1 to 2-4 at a dot concentration of 30% is “×”.

[0332] This shows that printability is good when the black area ratio is below 0.15%.

[0333] [Examples 3-1 to 3-7 and Comparative Example 3-1]

[0334] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate described in Table 3 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated, thereby forming an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. The coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film using a gravure printing press to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm. An oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 3-1 to 3-7 and Comparative Example 3-1.

[0335] [Examples 3-8]

[0336] Instead of setting a base layer on the corona-treated surface of the resin substrate α8, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Examples 3-8 is obtained in the same way as in Examples 3-4.

[0337] <Printability Evaluation>

[0338] Using a gravure printing press, ink (trade name: N920LPGT, manufactured by Toyo Ink Co., Ltd.) was printed on the oxygen barrier coating of each example of gas-barrier film at dot density levels of 5% to 50% (per 5% scale). The ink viscosity was 14 seconds ("Zencapsulation #3", 25°C). The printing speed was set to 150 m / min and the drying temperature to 50°C. The printed surface was observed using an optical microscope, and the number of defects was counted. In a 6 mm square area, if there were fewer than 5 defects, it was judged as ○; if there were 5 to 20 defects, it was judged as △; if there were 21 or more defects, it was judged as ×. The judgment results are shown in Table 3.

[0339] It should be noted that "spotting" refers to a state where the ink has poor adhesion to the film substrate, and some dots (half-dots) are not transferred. The fewer the spots, the better the printability of the highlights, up to a low dot density.

[0340] <Evaluation of oxygen and water vapor barrier properties after cooking>

[0341] Each example of a gas-barrier membrane was bonded to a CPP (polypropylene membrane) using an adhesive, thereby creating a gas-barrier laminated membrane for retort treatment consisting of a gas-barrier membrane / adhesive / CPP. The adhesive used was Mitsui Chemicals Polyurethane's two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent), and the CPP was Toray Film Processing's polypropylene membrane "Treffan ZK93KM" (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the membrane was configured so that the oxygen-barrier coating was on the adhesive side.

[0342] The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 150ml of tap water as the contents and then subjected to heat sterilization treatment (boiling treatment) in hot water at 120℃ for 30 minutes.

[0343] For the gas-barrier laminated membrane after cooking, the oxygen permeability (cm³) was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The measurement results are shown in Table 3.

[0344]

[0345] According to the results recorded in Table 3, in the gas barrier films of Examples 3-1 to 3-8, the black area ratio was less than 0.15%, and the oxygen permeability in an atmosphere of 30°C and 70% relative humidity was 2 cm⁻¹. 3 / (m 2 Below ·day·atm), good oxygen barrier properties were achieved.

[0346] On the other hand, in the gas-barrier membrane of Comparative Example 3-1, the black area ratio was 0.15% or more, and the oxygen permeability was 4.7 cm⁻¹. 3 / (m 2 Compared with Examples 3-1 to 3-8, good oxygen barrier properties were not obtained (day atm).

[0347] According to the results recorded in Table 3, the printability of the gas barrier films of Examples 3-1 to 3-8 is “○” when the dot concentration is above 30%.

[0348] On the other hand, the printability of the barrier film of Comparative Example 3-1 at a dot concentration of 30% is “×”.

[0349] This shows that printability is good when the black area ratio is below 0.15%.

[0350] [Examples 4-1 to 4-5 and Comparative Example 4-1]

[0351] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate described in Table 4 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, metallic aluminum was evaporated, and oxygen was introduced into it, thereby forming an inorganic oxide layer composed of aluminum oxide with a thickness of 20 nm on the base layer. Subsequently, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. The coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film using a gravure printing press to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm. An oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 4-1 to 4-5 and Comparative Example 4-1.

[0352] [Examples 4-6]

[0353] Instead of setting a base layer on the corona-treated surface of the resin substrate α8, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 4-6 is obtained in the same way as in Example 4-2.

[0354] <Printability Evaluation>

[0355] Using a gravure printing press, ink (trade name: N920LPGT, manufactured by Toyo Ink Co., Ltd.) was printed on the oxygen barrier coating of each example of gas-barrier film at dot density levels of 5% to 50% (per 5% scale). The ink viscosity was 14 seconds ("Zencapsulation #3", 25°C). The printing speed was set to 150 m / min and the drying temperature to 50°C. The printed surface was observed using an optical microscope, and the number of defects was counted. In a 6 mm square area, if there were fewer than 5 defects, it was judged as ○; if there were 5 to 20 defects, it was judged as △; if there were 21 or more defects, it was judged as ×. The judgment results are shown in Table 4.

[0356] It should be noted that "spotting" refers to a state where the ink has poor adhesion to the film substrate, and some dots (half-dots) are not transferred. The fewer the spots, the better the printability of the highlights, up to a low dot density.

[0357] <Evaluation of oxygen and water vapor barrier properties after cooking>

[0358] Each example of a gas-barrier membrane was bonded to a CPP (polypropylene membrane) using an adhesive, thereby creating a gas-barrier laminated membrane for retort treatment consisting of a gas-barrier membrane / adhesive / CPP. The adhesive used was Mitsui Chemicals Polyurethane's two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent), and the CPP was Toray Film Processing's polypropylene membrane "Treffan ZK93KM" (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the membrane was configured so that the oxygen-barrier coating was on the adhesive side.

[0359] The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 150ml of tap water as the contents and then subjected to heat sterilization treatment (boiling treatment) in hot water at 120℃ for 30 minutes.

[0360] For the gas-barrier laminated membrane after cooking, the oxygen permeability (cm³) was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The measurement results are shown in Table 4.

[0361]

[0362] According to the results recorded in Table 4, the black area fraction of the gas barrier films in Examples 4-1 to 4-6 is less than 0.15%, and the oxygen permeability in an atmosphere of 30°C and 70% relative humidity is 1 cm. 3 / (m 2 Good oxygen barrier properties were obtained at a temperature below 1.5 atm (days). On the other hand, the gas barrier membrane of Comparative Example 4-1 had a black area ratio of 0.15% or higher and an oxygen permeability of 1.5 cm⁻¹. 3 / (m 2 Compared with Examples 4-1 to 4-6, good oxygen barrier properties were not obtained (day atm).

[0363] According to the results recorded in Table 4, the printability of the gas barrier films of Examples 4-1 to 4-6 is “○” when the dot concentration is above 30%.

[0364] On the other hand, the printability of the barrier film of Comparative Example 4-1 at a dot concentration of 30% is “×”.

[0365] This shows that printability is good when the black area ratio is below 0.15%.

[0366] [Examples 5-1 to 5-5 and Comparative Examples 5-1 to 5-3]

[0367] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate described in Table 5 to form a coating film. The coating film was dried in an oven at 60°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated to form an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, a coating agent for forming an organic-inorganic composite coating prepared in Manufacturing Example 4 was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 60°C for 10 seconds, forming an oxygen barrier coating composed of an organic-inorganic composite coating with a thickness of 0.3 μm, thus obtaining the gas barrier films of Examples 5-1 to 5-5 and Comparative Examples 5-1 to 5-3.

[0368] [Examples 5-6]

[0369] Instead of setting a base layer on the corona-treated surface of the resin substrate α14, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 5-6 is obtained in the same way as in Example 5-2.

[0370] [Examples 5-7 to 5-11 and Comparative Examples 5-4 to 5-6]

[0371] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate described in Table 5 to form a coating film. The coating film was dried in an oven at 60°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, metallic aluminum was evaporated, and oxygen was introduced into it, thereby forming an inorganic oxide layer composed of aluminum oxide with a thickness of 20 nm on the base layer. Subsequently, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 60°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. The coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film using a gravure printing press to form a coating film. The coating film was dried in an oven at 50°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm. An oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 5-7 to 5-11 and Comparative Examples 5-4 to 5-6.

[0372] [Examples 5-12]

[0373] Instead of setting a base layer on the corona-treated surface of the resin substrate α14, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 5-12 is obtained in the same manner as in Examples 5-8.

[0374] [Example 5-13]

[0375] Instead of setting an inorganic oxide layer on the base layer formed on the corona-treated surface of the resin substrate α14, a multivalent metal compound coating is formed. Otherwise, the gas barrier film of Examples 5-13 is obtained in the same manner as in Examples 5-8.

[0376] <Evaluation of oxygen barrier properties and water vapor barrier properties before and after boiling treatment>

[0377] Each example of a gas-barrier membrane was bonded to LLDPE (polyethylene film) using an adhesive, thereby creating a gas-barrier laminated membrane for boiling treatment consisting of a gas-barrier membrane / adhesive / LLDPE. The adhesive used was Mitsui Chemicals' two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent), and the LLDPE used was Mitsui Chemicals Azusero's polyethylene film TUX MC-S (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the gas-barrier membrane was configured so that the oxygen-barrier coating was on the adhesive side.

[0378] The obtained gas-barrier laminated film was used to make an A5-sized four-sided sealed bag, which was filled with 150ml of tap water as the contents and then subjected to heat sterilization treatment (boiling treatment) in hot water at 90℃ for 30 minutes.

[0379] For the gas-barrier laminated membranes before and after boiling treatment, the oxygen permeability (cm²) was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The measurement results are shown in Table 5.

[0380]

[0381] According to the results recorded in Table 5, the black area ratio of the gas barrier films in Examples 5-1 to 5-6 is less than 0.15%, and the oxygen permeability in an atmosphere of 30°C and 70% relative humidity is 2 cm before boiling.3 / (m 2 (day atm) or less, 3cm after boiling 3 / (m 2 Below ·day·atm), good oxygen barrier properties were achieved.

[0382] The gas barrier films of Examples 5-7 to 5-13 have a black area fraction of less than 0.15%, and their oxygen permeability in an atmosphere of 30°C and 70% relative humidity is 1 cm before and after boiling. 3 / (m 2 Below ·day·atm), good oxygen barrier properties were achieved.

[0383] On the other hand, the black area ratio of the gas-barrier films in Comparative Examples 5-1 to 5-3 was 0.15% or more, and the oxygen permeability was 2 cm² before boiling. 3 / (m 2 (day atm) or above, 3cm after boiling 3 / (m 2 (days atm) or above, good oxygen barrier properties were not achieved.

[0384] The black area fraction of the gas-barrier membranes in Comparative Examples 5-4 to 5-6 was 0.15% or more, and the oxygen permeability was 1 cm before and after boiling. 3 / (m 2 (days atm) or above, good oxygen barrier properties were not achieved.

[0385] [Examples 6-1 to 6-4 and Comparative Examples 6-1 to 6-5]

[0386] In Examples 6-1 to 6-4 and Comparative Examples 6-1 to 6-5, the impact on the production batch of the resin substrate was studied.

[0387] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate shown in Table 6A to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed substrate layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. Further using a gravure printing press, a coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm, and an oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Experimental Examples 6-1 to 6-4 and Comparative Examples 6-1 to 6-5.

[0388] [Examples 6-5 to 6-8 and Comparative Examples 6-6 to 6-10]

[0389] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the corona-treated surface of the resin substrate shown in Table 6B to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated to form an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, a coating agent for forming an organic-inorganic composite coating prepared in Manufacturing Example 4 was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, forming an oxygen barrier coating composed of an organic-inorganic composite coating with a thickness of 0.3 μm, thus obtaining the gas barrier films of Examples 6-5 to 6-8 and Comparative Examples 6-6 to 6-10.

[0390] The black area ratio, oxygen permeability, and printability of the resin substrate were evaluated using the same method as in Examples 1-1 to 1-8. The results are shown in Tables 6A and 6B.

[0391]

[0392]

[0393] First, the resin substrates used in Examples 6-1 to 6-4 and Comparative Example 6-1 were identical in material, product number, manufacturer, and thickness, but from different production batches. Similarly, the resin substrates used in Examples 6-5 to 6-8 and Comparative Example 6-6 were identical in material, product number, manufacturer, and thickness, but from different production batches. However, the black area ratio of the resin substrates measured by the above method varied depending on each production batch. That is, based on the measurement results of the black area ratio shown in Tables 6A and 6B, it can be confirmed that the black area ratio measured by the above method is not an inherent value of the type of resin substrate (α8 or α9), but rather a value that fluctuates depending on the production batch.

[0394] Next, based on the results shown in Tables 6A and 6B, the gas barrier films (with a black area ratio of resin substrate of 0.15% or less) involved in Examples 6-1 to 6-4 and Examples 6-5 to 6-8 exhibited good oxygen barrier properties in an atmosphere of 30°C and 70% relative humidity, and their printability evaluation at a dot concentration of 30% or higher was "○". In contrast, the gas barrier film involved in Comparative Example 6-1 had a black area ratio of resin substrate exceeding 0.15%, and compared with Examples 6-1 to 6-4 having the same structure, it had a higher oxygen permeability and worse printability. Similarly, the gas barrier film involved in Comparative Example 6-6 also had a black area ratio of resin substrate exceeding 0.15%, and compared with Examples 6-5 to 6-8 having the same structure, it had a higher oxygen permeability and worse printability.

[0395] Based on these results, it can be confirmed that even when using the same type of resin substrate to form the same gas barrier film, the performance of the gas barrier film will vary depending on the production batch of the resin substrate. However, if the black area ratio of the resin substrate is less than 0.15%, the impact caused by the production batch of the resin substrate can be reduced.

[0396] Hereinafter, Embodiment 2 of the present disclosure will be described in more detail through examples and comparative examples. However, the present disclosure is not limited to the following examples. The materials used in the following examples are described below.

[0397] [Materials Used]

[0398] <Resin substrate>

[0399] β1: Biaxially stretched polypropylene film (trade name: ME-1, thickness 20μm, surface layer is polyolefin copolymer resin, manufactured by Mitsui Chemicals Azusero Co., Ltd.).

[0400] β2: Biaxially stretched polypropylene film (trade name: P2111, thickness 20μm, surface layer is polyolefin copolymer resin, manufactured by Toyobo Co., Ltd.).

[0401] β3: Biaxially stretched polypropylene film (trade name: VPH2011, thickness 20μm, surface layer is polyolefin copolymer resin, contains AB agent with an average particle size of 2μm, manufactured by AJPlast).

[0402] β4: Biaxially stretched polypropylene film (trade name: VPH2011, thickness 20μm, surface layer is polyolefin copolymer resin, contains AB agent with an average particle size of 4μm, manufactured by AJPlast).

[0403] β5: Biaxially stretched polypropylene film (trade name: TS19TIMCP, thickness 19μm, surface layer is polyolefin copolymer resin, manufactured by Max Speciality Films Limited).

[0404] β6: Biaxially stretched polypropylene film (trade name: TS18TIV, thickness 18μm, surface layer is polyolefin copolymer resin, manufactured by Max Speciality Films Limited).

[0405] β7: Biaxially stretched polypropylene film (trade name: TS18TI-TPN, thickness 18μm, surface layer is polypropylene homopolymer, manufactured by MaxSpeciality Films Limited).

[0406] β8: Biaxially stretched polypropylene film (trade name: M-1, thickness 20μm, surface layer is polypropylene homopolymer, manufactured by Mitsui Chemicals Azusero Co., Ltd.).

[0407] [Determination of the number of protrusions on the surface of the resin substrate]

[0408] For the surface (first surface) of the resin substrate β1 to β8 on the side where the oxygen barrier coating is formed, the number of protrusions with a Feretta diameter of 8 μm or more was determined according to the above measurement conditions. The results are shown in Tables 7 to 10.

[0409] [Examples 7-1 to 7-3 and Comparative Examples 7-1 to 7-5]

[0410] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the first surface of the resin substrate listed in Table 7 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated, thereby forming an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, a coating agent for forming an organic-inorganic composite coating prepared in Manufacturing Example 4 was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, forming an oxygen barrier coating composed of an organic-inorganic composite coating with a thickness of 0.3 μm, thus obtaining the gas barrier films of Examples 7-1 to 7-3 and Comparative Examples 7-1 to 7-5.

[0411] [Example 7-4]

[0412] Instead of setting a base layer on the first surface of the resin substrate β3, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 7-4 is obtained in the same manner as in Example 7-3.

[0413] <Evaluation of oxygen barrier properties, water vapor barrier properties, and lamination strength after cooking>

[0414] Gas-barrier membranes were bonded to CPP (polypropylene film) using an adhesive to create a gas-barrier laminated membrane for retort treatment, consisting of a gas-barrier membrane, adhesive, and CPP. Mitsui Chemicals' two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent) was used as the adhesive, and Toray Film Processing's polypropylene film "Treffan ZK93KM" (60μm) was used as the CPP. Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the oxygen-barrier coating of the gas-barrier membrane was configured so that the adhesive side was the bonded side. The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 200ml of tap water and then subjected to heat sterilization (boiling treatment) in hot water at 120°C for 30 minutes. The oxygen permeability (cm²) of the gas-barrier laminated film after boiling treatment was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 •day). The test results are shown in Table 7. For the gas barrier laminated film after cooking, the test piece was cut into short strips 15 mm wide, and T-shaped and 180° peels were performed using a universal testing machine "Tensilon RTC-1250" at a peel speed of 300 m / min to determine the lamination strength between the gas barrier film and the CPP film. The test results are shown in Table 7.

[0415]

[0416] According to the results recorded in Table 7, the first surface of the resin substrate is a polyolefin copolymer resin, and the number of protrusions with a Feretta diameter of 8 μm or more on the first surface of the resin substrate is 20 per mm. 2 The oxygen permeability of the barrier membranes in Examples 7-1 to 7-4 below is 3 cm⁻¹ in an atmosphere of 30°C and 70% RH. 3 / (m 2 Below 1000 atm (days), it exhibits good oxygen barrier properties, with a water vapor permeability of 1 g / (m³) at 40°C and 90% RH. 2 The resin exhibits good water vapor barrier properties (days and below). On the other hand, there are more than 20 protrusions per mm with a Freette diameter of 8 μm or more on the first surface of the resin substrate. 2 In the gas-barrier membranes of Comparative Examples 7-1 to 7-3, the oxygen permeability value exceeded 3 cm. 3 / (m 2 The water vapor transmission rate (water vapor permeability) exceeds 1 g / (m·day·atm). 2 (day), oxygen barrier and water vapor barrier properties deteriorate.

[0417] According to the results recorded in Table 7, in Comparative Examples 7-4 to 7-5, where the first side of the resin substrate was a homopolymer of polypropylene, the lamination strength after cooking was less than 2 N / 15 mm, indicating insufficient strength. In contrast, Examples 7-1 to 7-4, where the first side of the resin substrate was a polyolefin copolymer, also exhibited sufficient lamination strength of 2 N / 15 mm or more after cooking. In particular, Example 7-4 showed good lamination strength even without a base layer. Furthermore, "substrate fracture" in Table 7 indicates that no peeling occurred between the gas barrier film and the CPP film, the resin substrate fractured at a strength of 2 N / 15 mm or more, and the lamination strength was sufficiently high.

[0418] [Examples 8-1 to 8-3 and Comparative Examples 8-1 to 8-3]

[0419] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the first surface of the resin substrate listed in Table 8 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, a mixture containing two or more of metallic silicon, silicon monoxide, and silicon dioxide was evaporated, thereby forming an inorganic oxide layer composed of silicon oxide with a thickness of 30 nm on the base layer. Subsequently, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. Further using a gravure printing press, a coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm, and an oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 8-1 to 8-3 and Comparative Examples 8-1 to 8-3.

[0420] [Example 8-4]

[0421] Instead of setting a base layer on the first surface of the resin substrate β3, an inorganic oxide layer is directly formed. Otherwise, the gas barrier film of Example 8-4 is obtained in the same manner as in Example 8-3.

[0422] <Evaluation of oxygen barrier properties, water vapor barrier properties, and lamination strength after cooking>

[0423] Each example of a gas-barrier membrane was bonded to a CPP (polypropylene membrane) using an adhesive, thereby creating a gas-barrier laminated membrane for retort treatment consisting of a gas-barrier membrane / adhesive / CPP. The adhesive used was Mitsui Chemicals Polyurethane's two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent), and the CPP was Toray Film Processing's polypropylene membrane "Treffan ZK93KM" (60μm). Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the membrane was configured so that the oxygen-barrier coating was on the adhesive side. The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 200ml of tap water and then subjected to heat sterilization (boiling treatment) in hot water at 120°C for 30 minutes. The oxygen permeability (cm²) of the gas-barrier laminated film after boiling treatment was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The test results are shown in Table 8. For the gas barrier laminated film after cooking, the test piece was cut into short strips 15 mm wide, and T-shaped and 180° peels were performed using a universal testing machine "Tensilon RTC-1250" at a peel speed of 300 m / min to determine the lamination strength between the gas barrier film and the CPP film. The test results are shown in Table 8.

[0424]

[0425] According to the results recorded in Table 8, the first surface of the resin substrate is a polyolefin copolymer resin, and the number of protrusions with a Feretta diameter of 8 μm or more on the first surface of the resin substrate is 20 per mm. 2 The oxygen permeability of the barrier membranes in Examples 8-1 to 8-4 below, under an atmosphere of 30°C and 70% RH, is 2 cm. 3 / (m 2 Below ·day·atm), it exhibits good oxygen barrier properties. On the other hand, the first surface of the resin substrate has more than 20 protrusions with a Freret diameter of 8μm or more per mm. 2 Alternatively, in Comparative Examples 8-1 to 8-3, where the first surface of the resin substrate is polypropylene homopolymer, the oxygen permeability of the barrier membrane exceeds 2 cm⁻¹. 3 / (m 2·day·atm), poor oxygen barrier properties.

[0426] According to the results recorded in Table 8, in Comparative Examples 8-2 to 8-3, where the first side of the resin substrate was a polypropylene homopolymer, the lamination strength after cooking was less than 2 N / 15 mm, indicating insufficient strength. In contrast, Examples 8-1 to 8-4, where the first side of the resin substrate was a polyolefin copolymer, exhibited sufficient lamination strength of 2 N / 15 mm or more even after cooking. In particular, Example 8-4 showed good lamination strength even without a base layer.

[0427] [Examples 9-1 to 9-3 and Comparative Examples 9-1 to 9-3]

[0428] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the first surface of the resin substrate listed in Table 9 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed substrate layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. Further using a gravure printing press, a coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm, and an oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier films of Examples 9-1 to 9-3 and Comparative Examples 9-1 to 9-3.

[0429] <Evaluation of oxygen barrier properties, water vapor barrier properties, and lamination strength after cooking>

[0430] Gas-barrier membranes were bonded to CPP (polypropylene film) using an adhesive to create a gas-barrier laminated membrane for retort treatment, consisting of a gas-barrier membrane, adhesive, and CPP. Mitsui Chemicals' two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent) was used as the adhesive, and Toray Film Processing's polypropylene film "Treffan ZK93KM" (60μm) was used as the CPP. Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the oxygen-barrier coating of the gas-barrier membrane was configured so that the adhesive side was the bonded side. The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 200ml of tap water and then subjected to heat sterilization (boiling treatment) in hot water at 120°C for 30 minutes. The oxygen permeability (cm²) of the gas-barrier laminated film after boiling treatment was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2 ·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The test results are shown in Table 9. For the gas barrier laminated film after cooking, the test piece was cut into short strips 15 mm wide, and T-shaped and 180° peels were performed using a universal testing machine "Tensilon RTC-1250" at a peel speed of 300 m / min to determine the lamination strength between the gas barrier film and the CPP film. The test results are shown in Table 9.

[0431]

[0432] According to the results recorded in Table 9, the first surface of the resin substrate is a polyolefin copolymer resin, and the number of protrusions with a Feretta diameter of 8 μm or more on the first surface of the resin substrate is 20 per mm. 2 The oxygen permeability of the barrier membranes in Examples 9-1 to 9-3 below, under an atmosphere of 30°C and 70% RH, is 2 cm. 3 / (m 2 Below 1000 N·m, it exhibits good oxygen barrier properties, and the lamination strength after cooking is above 2 N / 15 mm, demonstrating sufficient lamination strength. Furthermore, it has more than 20 protrusions per mm with a Ferrette diameter of 8 μm or more on the first surface of the resin substrate. 2 In the gas-barrier membranes of Comparative Examples 9-1 to 9-3, the oxygen permeability value exceeded 2 cm⁻¹. 3 / (m 2 ·day·atm), poor oxygen barrier properties.

[0433] [Example 10-1 and Comparative Example 10-1]

[0434] Using a gravure printing press, the mixture for forming the base layer prepared in Manufacturing Example 1 was coated onto the first surface of the resin substrate listed in Table 10 to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds, thereby forming a base layer with a thickness of 0.1 μm. Next, using a vacuum evaporation apparatus employing electron beam heating, metallic aluminum was evaporated, and oxygen was introduced into it, thereby forming an inorganic oxide layer composed of aluminum oxide with a thickness of 20 nm on the base layer. Next, using a gravure printing press, a coating agent with the polycarboxylate polymer prepared in Manufacturing Example 2 as the main component was coated onto the formed inorganic oxide layer to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polycarboxylate polymer film with a thickness of 0.2 μm. Further using a gravure printing press, a coating agent with the polyvalent metal compound prepared in Manufacturing Example 3 as the main component was coated onto the polycarboxylate polymer film to form a coating film. The coating film was dried in an oven at 100°C for 10 seconds to form a polyvalent metal compound film with a thickness of 0.2 μm, and an oxygen barrier film composed of polycarboxylate polyvalent metal salt film was formed, thereby obtaining the gas barrier film of Example 10-1 and Comparative Example 10-1.

[0435] <Evaluation of oxygen barrier properties, water vapor barrier properties, and lamination strength after cooking>

[0436] Gas-barrier membranes were bonded to CPP (polypropylene film) using an adhesive to create a gas-barrier laminated membrane for retort treatment, consisting of a gas-barrier membrane, adhesive, and CPP. Mitsui Chemicals' two-component curing adhesive "Takelac A620" (main agent) / "Takenet A65" (curing agent) was used as the adhesive, and Toray Film Processing's polypropylene film "Treffan ZK93KM" (60μm) was used as the CPP. Dry lamination was performed using a HIRANO TECSEED TM-MC multi-functional coating machine, and curing was carried out at 40°C for 3 days. It should be noted that the oxygen-barrier coating of the gas-barrier membrane was configured so that the adhesive side was the bonded side. The obtained gas-barrier laminated film was used to make A5-sized four-sided sealed bags, which were filled with 200ml of tap water and then subjected to heat sterilization (boiling treatment) in hot water at 120°C for 30 minutes. The oxygen permeability (cm²) of the gas-barrier laminated film after boiling treatment was measured using an oxygen permeability measuring device (trade name: OXTRAN-2 / 20, manufactured by MOCON) at 30°C and 70% RH. 3 / (m 2·day·atm)). Additionally, the water vapor transmission rate (g / (m) was measured using a water vapor transmission rate measuring device (trade name: PERMATRAN-W-3 / 33, manufactured by MOCON) at 40°C and 90% RH. 2 The test results are shown in Table 10. For the gas barrier laminated film after cooking, the test piece was cut into short strips 15 mm wide, and T-shaped and 180° peels were performed using a universal testing machine "Tensilon RTC-1250" at a peel speed of 300 m / min to determine the lamination strength between the gas barrier film and the CPP film. The test results are shown in Table 10.

[0437]

[0438] According to the results recorded in Table 10, the first surface of the resin substrate is a polyolefin copolymer resin, and the number of protrusions with a Feretta diameter of 8 μm or more on the first surface of the resin substrate is 20 per mm. 2 The oxygen permeability of the barrier membrane in Example 10-1 below is 2 cm⁻¹ in an atmosphere of 30°C and 70% RH. 3 / (m 2 The film exhibits good oxygen barrier properties (at a time) and a lamination strength of 2 N / 15 mm or more after cooking, demonstrating sufficient lamination strength. On the other hand, in Comparative Example 10-1, where the first side of the resin substrate is a polypropylene homopolymer, the lamination strength (T-peel) after cooking is less than 2 N / 15 mm, and sufficient strength is not obtained.

[0439] Industrial applicability

[0440] The gas barrier membrane disclosed herein consistently exhibits excellent gas barrier properties, even after cooking. Furthermore, the surface condition of the substrate membrane can be easily controlled, and quality can be stabilized even when the oxygen barrier coating is thinned, thereby reducing raw material costs.

[0441] Furthermore, the gas barrier film disclosed herein exhibits excellent printability. Therefore, printing can be easily and aesthetically pleasingly performed on the surface of the gas barrier film.

[0442] The gas barrier film disclosed herein can be used, for example, as a packaging material, and also as a packaging material for boiling or cooking treatments. By using the gas barrier film of this disclosure as a packaging material, the quality retention of the contents can be improved.

[0443] The gas barrier membrane disclosed herein can also be used for purposes other than packaging materials. Examples of uses other than packaging materials include: membranes for electronic devices, membranes for solar cells, various functional membranes for fuel cells, substrate membranes, etc.

[0444] [Explanation of Symbols]

[0445] 1. Gas barrier membrane

[0446] 10 Resin substrate

[0447] 20 Oxygen Barrier Coating

[0448] 30 Basal layer

[0449] 40 Inorganic oxide layer

Claims

1. A gas barrier membrane, comprising: resin substrate, An oxygen barrier coating disposed on at least one side of the resin substrate, and One or both of the base layer and the inorganic oxide layer disposed between the resin substrate and the oxygen barrier coating. The resin substrate contains an anti-blocking agent. The black area percentage of one side of the resin substrate, as measured by the following method, is less than 0.15%. <Determination Method> An arbitrary 1281 μm square region on one side of a resin substrate was photographed using an optical microscope to obtain a 1024 × 1024 pixel image. Image analysis software was used to convert the image into a 256 grayscale monochrome image. The most frequent value of the monochrome image's brightness was subtracted by 30, and the resulting value was used as a threshold. Values ​​below the threshold were set to black, and values ​​above the threshold were set to white to binarize the brightness. The size of the 1281 μm square region was defined as 100 μm. 2 The proportion of the total area of ​​the black regions mentioned above is called the black area ratio.

2. The gas barrier membrane according to claim 1, wherein, The resin substrate is polypropylene or polyethylene terephthalate.

3. The gas barrier membrane according to claim 1 or 2, wherein, The thickness of the substrate layer is 0.01 to 1 μm.

4. The gas barrier membrane according to claim 1 or 2, wherein, The base layer contains organic polymers as its main component. The organic polymer comprises at least one of polyacrylic acid resins, polyol resins, polyurethane resins, polyamide resins, and reaction products of these resins.

5. The gas barrier membrane according to claim 1 or 2, wherein, The thickness of the inorganic oxide layer is 1–200 nm.

6. The gas barrier membrane according to claim 1 or 2, wherein, The inorganic oxide layer is aluminum oxide or silicon oxide.

7. The gas barrier membrane according to claim 1 or 2, wherein, The thickness of the oxygen barrier coating is 0.05–1 μm.

8. The gas barrier membrane according to claim 1 or 2, wherein, The oxygen barrier coating is a coating comprising at least one of a metal alkoxide, a hydrolysate of a metal alkoxide, and a reaction product of a metal alkoxide or a hydrolysate of a metal alkoxide, and a water-soluble polymer.

9. The gas barrier membrane according to claim 8, wherein, The oxygen barrier coating comprises at least one of a silane coupling agent, a hydrolysate of a silane coupling agent, and a reaction product of a silane coupling agent or a hydrolysate of a silane coupling agent.

10. The gas barrier membrane according to claim 1 or 2, wherein, The oxygen barrier coating comprises a carboxylic acid polyvalent metal salt, which is a product of the reaction between the carboxyl group of a polycarboxylic acid polymer (A) and a polyvalent metal compound (B).

11. A method for manufacturing a gas barrier membrane, comprising the method for manufacturing a gas barrier membrane according to any one of claims 1 to 10, wherein: The process involves determining the black area percentage of the surface of a resin substrate raw material using the following measurement method, and preparing a resin substrate raw material with at least one surface having a black area percentage of 0.15% or less as the resin substrate; and The process of applying a coating agent to at least one side of the resin substrate to form at least the oxygen barrier coating. The resin substrate contains an anti-blocking agent. <Determination Method> An arbitrary 1281 μm square region on one side of a resin substrate was photographed using an optical microscope to obtain a 1024 × 1024 pixel image. Image analysis software was used to convert the image into a 256 grayscale monochrome image. The most frequent value of the monochrome image's brightness was subtracted by 30, and the resulting value was used as a threshold. Values ​​below the threshold were set to black, and values ​​above the threshold were set to white to binarize the brightness. The size of the 1281 μm square region was defined as 100 μm. 2 The proportion of the total area of ​​the black regions mentioned above is called the black area ratio.

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