Barrier film and laminate using same

Abstract

Provided is a barrier film that includes a vapor deposition film and a coating layer formed on an OPP film substrate, and that is capable of suppressing deterioration of barrier properties after heat sterilization treatment; and a laminate using the barrier film.　This barrier film is obtained by sequentially laminating a biaxially stretched polypropylene substrate, a base layer, and an aluminum oxide vapor deposition film. A peak top ratio P based on X-ray absorption fine structure analysis of the aluminum oxide vapor deposition film is 0.70 or more and less than 1.05.　P = (intensity peak top at around 1,572 eV) / (intensity peak top at around 1,566 eV)

Description

Barrier film and laminate using the same

[0001] The present invention relates to a barrier film and a laminate using the same.

[0002] Conventionally, laminated films having a film formed on a substrate such as a long film or sheet of plastic have been used in various applications. For example, a barrier laminated film has been developed in which a barrier layer made of a thin film of aluminum oxide or the like is provided on a plastic film to provide a barrier function against oxygen and water vapor.

[0003] As a method for producing a barrier film having an aluminum oxide thin film, for example, Patent Document 1 discloses a gas barrier film having excellent transparency and gas barrier properties, which is obtained by using a plasma activated vapor deposition method (a so-called plasma-assisted method during vapor deposition) in which high-density plasma is generated in a space between an aluminum evaporation source and a polymer film.

[0004] Furthermore, Patent Document 2 discloses an aluminum oxide vapor-deposited film in which a vapor-deposited film of low aluminum oxide is formed on a transparent plastic film, which is then subjected to a plasma treatment containing oxygen gas to form a vapor-deposited film of high aluminum oxide, which is then further subjected to a heat treatment at high humidity to form a vapor-deposited film of aluminum hydroxide.

[0005] On the other hand, in recent years, from the viewpoint of environmental consideration, mono-material packaging materials have been studied for the purpose of improving the recyclability of packaging materials. For example, laminates in which a polyolefin film such as a biaxially oriented polypropylene film (OPP film) is used as a substrate instead of the conventionally widely used polyester film (PET film), and a polyolefin film such as a non-oriented polypropylene film (CPP film) is used as a sealant layer to be laminated thereto, are being studied as mono-material packaging materials.

[0006] For example, Patent Document 3 listed below discloses a gas barrier laminate comprising a substrate layer containing a polyolefin-based resin, a barrier layer, and an overcoat layer containing a polyvinyl alcohol-based resin, wherein the surface hardness of the overcoat layer is 1.5 GPa or less as measured by nanoindentation. Thus, a laminate comprising a biaxially oriented polypropylene substrate, a barrier film in which an inorganic oxide vapor-deposited film and a coating layer having barrier properties are laminated in this order, and a sealant layer is known as a polyolefin-based monomaterial packaging material.

[0007] JP 2017-177343 A JP 11-170427 A WO2022 / 085586 International Publication

[0008] When a laminate made of a polyolefin-based mono-material packaging material is subjected to heat sterilization treatment such as boiling or retort, OPP film is inferior to PET film in heat resistance and strength, and therefore the barrier properties of the OPP film after heat sterilization treatment are significantly reduced compared to PET film.

[0009] In this regard, in conventional barrier films, the vapor deposition film suitable for the OPP film used as the vapor deposition substrate and the coating layer to be provided as needed have not been sufficiently studied. Further study is needed, particularly with regard to the vapor deposition film and coating layer that can withstand heat sterilization treatment when formed into a laminate.

[0010] Furthermore, Patent Document 3 specifies the composite elastic modulus and hardness of the coating layer, but focuses on the "suitability for processing" of the barrier film. For this reason, Patent Document 3 only specifies the composite elastic modulus and hardness of the coating layer "before heat sterilization treatment," and makes no mention of heat sterilization treatment or the barrier properties thereafter.

[0011] According to the investigations of the present inventors, it has been found that the composite elastic modulus and hardness of the coating layer vary before and after lamination and depending on whether or not heat sterilization has been performed. Therefore, even if the composite elastic modulus and hardness of the coating layer "before heat sterilization treatment" are specified as in Patent Document 3, it is not possible to predict the suppression of deterioration in barrier property when the laminate is subjected to heat sterilization treatment.

[0012] As a result of extensive research to solve the above problems, the present inventors have discovered a vapor-deposited film and a coating layer, which are optionally provided on an OPP film substrate, that are suitable for use in heat sterilization treatment when used as a laminate, in a barrier film that constitutes a polyolefin-based monomaterial packaging material, and have completed the present invention. Specifically, the present invention provides the following.

[0013] (1) A barrier film comprising a polypropylene substrate, an underlayer, and an aluminum oxide vapor-deposited film laminated in this order, wherein the aluminum oxide vapor-deposited film has a peak top ratio P of 0.70 or more and less than 1.05 when X-ray absorption fine structure analysis is performed on the surface of the barrier film opposite the polypropylene substrate side, as defined below: P = (intensity peak top near 1572 eV) / (intensity peak top near 1566 eV).

[0014] (2) The barrier film according to (1), wherein a coating layer having barrier properties is laminated on the aluminum oxide vapor-deposited film.

[0015] (3) The barrier film according to (2), wherein the coating layer has a ratio of silicon atoms to carbon atoms (Si / C) measured by X-ray photoelectron spectroscopy (XPS) of 1.30 or more and 1.65 or less.

[0016] (4) The barrier film according to (1), wherein the underlayer is an anchor coat layer formed on the polypropylene substrate.

[0017] (5) The barrier film according to (1), wherein the underlayer is a surface resin layer containing a polyamide resin formed on the polypropylene substrate.

[0018] (6) The barrier film according to (4), wherein the polypropylene substrate has at least a first layer and a second layer as both surface layers, the first layer being formed on the underlayer side, the first layer containing a copolymer of propylene and another monomer, the underlayer being the anchor coat layer, and the first layer of the polypropylene substrate, the anchor coat layer, the aluminum oxide vapor-deposited film, and the coating layer having barrier properties are laminated in this order.

[0019] (7) The barrier film according to (4), wherein the polypropylene substrate has at least a first layer and a second layer as both surface layers, the first layer being formed on the underlayer side, the first layer containing modified polypropylene, the underlayer being the surface resin layer containing the polyamide resin, and the first layer of the polypropylene substrate, the surface resin layer containing the polyamide resin, the aluminum oxide vapor-deposited film, and the coating layer having barrier properties are laminated in this order.

[0020] (8) The barrier film according to (1), wherein the polypropylene substrate has at least a first layer and a second layer as both surface layers, the second layer being formed on the surface opposite to the underlayer side, the second layer containing a copolymer of propylene and another monomer, and the first layer of the polypropylene substrate, the underlayer, the aluminum oxide vapor-deposited film, and the coating layer having barrier properties are laminated in this order.

[0021] (9) A heat-sterilized laminate comprising the barrier film according to any one of (1) to (8) and a sealant layer, the laminate being used for a packaging bag containing retort food or boiled food, wherein the composite modulus and indentation hardness of the coating layer of the laminate, as measured by nanoindentation from a cross section of the coating layer, are 5.0 GPa or more and 8.5 GPa or less, and the indentation hardness is 0.9 GPa or more and 1.7 GPa or less.

[0022] (10) A packaging product comprising the laminate according to (9).

[0023] The barrier film of the present invention comprises a vapor-deposited film formed on an OPP film substrate and an optional coating layer, and yet can suppress a decrease in barrier properties after heat sterilization treatment.

[0024] FIG. 1 is a cross-sectional view showing an example of a barrier film according to the present embodiment; FIG. 2 is a diagram showing an example of a film forming apparatus according to an embodiment of the present invention; FIG. 3 is a cross-sectional view showing an example of a plasma pretreatment mechanism of the film forming apparatus; FIG. 4 is a plan view showing an example of an electrode unit and a magnetic field forming unit of the plasma pretreatment mechanism of the film forming apparatus; FIG. 5 is a cross-sectional view showing an example of an electrode unit and a magnetic field forming unit of the plasma pretreatment mechanism of the film forming apparatus; FIG. 6 is a cross-sectional view showing an example of a film forming mechanism of the film forming apparatus; FIG. 7 is a cross-sectional view showing an example of a laminate using the barrier film of the present invention; FIG. 8 is a cross-sectional view showing another example of a laminate using the barrier film of the present invention; FIG. 9 is a diagram showing an XAFS spectrum of the barrier film of Example 1; FIG. 10 is a diagram showing the analysis result of the XAFS spectrum of the barrier film of Example 1; FIG. 11 is a diagram showing the analysis result of the XAFS spectrum of the barrier film of Example 2; FIG. 12 is a diagram showing the analysis result of the XAFS spectrum of the barrier film of Comparative Example 4; FIG. 13 is a diagram showing the analysis result of the XAFS spectrum of the barrier film of Comparative Example 5.

[0025] Specific embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments and can be practiced with appropriate modifications within the scope of the object of the present invention. Furthermore, in this specification, the expression "X to Y" (X and Y are arbitrary numerical values) means "at least X and at most Y."

[0026] FIG. 1 is a cross-sectional view showing an example of a barrier film according to the present embodiment. A barrier film produced using the film-forming apparatus according to the present embodiment includes, for example, a substrate 100 corresponding to the biaxial polypropylene substrate of the present invention, an underlayer 115, a vapor-deposited film 120, and, if necessary, a coating layer 130, as in the barrier film 100A shown in FIG. 1 . In the example shown in FIG. 1 , the underlayer 115 is located on one surface of the substrate 100. In addition, in the example shown in FIG. 1 , the barrier film 100A is formed by laminating the substrate 100, the underlayer 115, the vapor-deposited film 120, and the coating layer 130 in this order, with the coating layer 130 located on the surface of the barrier film. The vapor-deposited film 120 and the coating layer 130 form a barrier layer.

[0027] In this specification, "laminated in this order" means that the polypropylene base material, the underlayer, the aluminum oxide vapor deposition film, and the coating layer having barrier properties are laminated in this order, and further layers such as an anchor coat layer described below may be laminated between these layers.

[0028] Each layer constituting the barrier film 100A will be described below.

[0029] [Polypropylene base material] The polypropylene base material 100 is a polypropylene base material that has been subjected to a biaxial stretching treatment. Hereinafter, except when referring to the stretching treatment, when simply referring to a "polypropylene base material", it means a polypropylene base material that has been subjected to a biaxial stretching treatment.

[0030] The polypropylene substrate is composed of at least polypropylene. The polypropylene may be any of a propylene homopolymer, a propylene random copolymer, and a propylene block copolymer, or may be a mixture of two or more selected from these.

[0031] A propylene homopolymer is a polymer of propylene only. A propylene random copolymer is a random copolymer of propylene and an α-olefin other than propylene. A propylene block copolymer is a copolymer having a polymer block of propylene and a polymer block of at least an α-olefin other than propylene. The latter polymer block may be a polymer block of propylene and an α-olefin other than propylene.

[0032] Examples of the α-olefin include α-olefins having 2 to 20 carbon atoms, and specific examples include ethylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene.

[0033] Among polypropylenes, it is preferable to use a random copolymer from the viewpoint of transparency. When the rigidity and heat resistance of the laminate are important, it is preferable to use a homopolymer. When the impact resistance of the laminate is important, it is preferable to use a block copolymer.

[0034] In one embodiment, the polypropylene may have a melt flow rate (MFR) of 0.1 g / 10 min or more and 50 g / 10 min or less, or 0.3 g / 10 min or more and 30 g / 10 min or less, from the viewpoint of film-forming properties and processability. The MFR of polypropylene is measured in accordance with ASTM D1238 at a temperature of 230°C and a load of 2.16 kg.

[0035] As the polypropylene, biomass-derived polypropylene or mechanically recycled or chemically recycled polypropylene may be used.

[0036] The polypropylene content in the polypropylene base material is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more.

[0037] The polypropylene substrate may contain a resin material other than polypropylene, such as polyolefins such as polyethylene, (meth)acrylic resins, vinyl resins, cellulose resins, polyamides, polyesters, and ionomer resins.

[0038] The polypropylene substrate may contain additives such as crosslinkers, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, lubricants, antistatic agents, pigments, and modifying resins.

[0039] The polypropylene substrate is a substrate that has been subjected to a biaxial stretching treatment. This can improve, for example, the heat resistance, impact resistance, water resistance, and dimensional stability of the barrier substrate. A laminate including such a barrier substrate is suitable, for example, as a packaging material that is subjected to a boiling treatment or a retort treatment.

[0040] The stretching ratio when stretching in the machine direction (machine direction, MD direction of the substrate) is preferably 2 to 15 times, more preferably 5 to 13 times. The stretching ratio when stretching in the transverse direction (direction perpendicular to the MD direction, TD direction) is preferably 2 to 15 times, more preferably 5 to 13 times. By setting the stretching ratio to 2 times or more, the strength and heat resistance of the polypropylene substrate can be further improved, and when the polypropylene substrate is used as the outermost layer, the printability of the polypropylene substrate can be improved. From the viewpoint of the breaking limit of the polypropylene substrate, the stretching ratio is preferably 15 times or less.

[0041] The thickness of the polypropylene substrate is preferably 10 μm or more and 100 μm or less, more preferably 10 μm or more and 50 μm or less, and even more preferably 15 μm or more and 25 μm or less. When the thickness is equal to or more than the lower limit, for example, the strength and heat resistance of the barrier substrate can be further improved. When the thickness is equal to or less than the upper limit, for example, the processability of the barrier substrate can be further improved.

[0042] The polypropylene substrate may be a coextrusion stretched film. It can be produced by forming a laminated film using a conventionally known T-die method or inflation method, and then stretching the laminated film. When forming the film using the inflation method, the laminated film may be stretched simultaneously.

[0043] The polypropylene substrate may be surface-treated. This can improve the adhesion between the polypropylene substrate and other layers, for example. Examples of surface treatment methods include physical treatments such as corona discharge treatment, ozone treatment, low-temperature plasma treatment using one or more gases selected from oxygen gas, argon gas, nitrogen gas, etc., and glow discharge treatment; and chemical treatments such as oxidation treatment using chemicals. In addition, an easy-adhesion layer may be provided on the surface of the polypropylene substrate.

[0044] When a polypropylene substrate is used as the outermost layer of a laminate, a printed layer may be provided on the second layer. The image formed on the printed layer is not particularly limited, and examples thereof include letters, patterns, symbols, and combinations thereof. The printed layer may also be formed using ink derived from biomass. This further reduces the environmental impact.

[0045] Examples of methods for forming the printed layer include conventionally known printing methods such as gravure printing, offset printing, and flexographic printing. Among these, flexographic printing is preferred from the viewpoint of reducing environmental impact.

[0046] The polypropylene substrate is preferably transparent. Specifically, it preferably has a high total light transmittance as measured in accordance with JIS K 7361-1:1997. Specifically, the total light transmittance is preferably 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

[0047] The substrate 100 of the roll is preferably humidified in a process for forming an underlayer or in a humidity conditioning process after the formation of the underlayer. This improves the barrier properties. It also prevents substrate breakage due to sticking during unwinding in the vapor deposition process described below. One example of humidity conditioning conditions is storage at a temperature of 22 to 30°C and a relative humidity of 40 to 65% RH for 1 to 7 days. Rewinding the roll before storage is also effective for humidity conditioning. In this case, the rewinding process is preferably also performed under the above humidity conditioning conditions.

[0048] The polypropylene substrate may be a multilayer film including at least a first layer and a second layer, the first layer being a layer on one side of the polypropylene substrate (the side on which a barrier layer such as a vapor-deposited film is formed), and the second layer being a layer on the other side of the polypropylene substrate.

[0049] The first layer and the second layer may each be a propylene random copolymer, which is a random copolymer of propylene and an α-olefin other than propylene. When the first layer and the second layer are random copolymers, the adhesion between the layer and other layers in contact with the layer can be improved. Examples of α-olefins include ethylene, 1-butene, and 1-hexene.

[0050] The first layer may be made of modified polypropylene, which improves adhesion to the polyamide resin when the undercoat layer described below is made of a polyamide resin.

[0051] The polypropylene substrate may include a third intermediate layer between the first and second layers. The intermediate layer preferably contains a polypropylene homopolymer. The intermediate layer may have a single-layer structure or a multi-layer structure.

[0052] A specific example of a three-layer structure is a propylene random copolymer / propylene homopolymer / propylene random copolymer, in the order of first layer / third layer / second layer from the side on which the vapor-deposited film is formed. In this case, when the first layer is a propylene random copolymer and the underlayer (described later) is an anchor coat layer, adhesion to the anchor coat layer is improved. Furthermore, when the second layer is a propylene random copolymer, adhesion to the first adhesive layer 161 for laminating the sealant layer 150 is improved, for example, when forming the laminate shown in FIG. 7 (described later).

[0053] Another example of a specific three-layer structure is a structure in which the first layer, the third layer, and the second layer are, in order from the side on which the vapor-deposited film is formed, modified polypropylene, propylene homopolymer, and propylene random copolymer. In this case, when the underlayer described below is made of polyamide resin, the first layer being modified polypropylene improves adhesion to the polyamide resin. Furthermore, when the third layer is made of propylene random copolymer, for example, when forming the laminate shown in FIG. 7 described below, adhesion to the first adhesive layer 161 for laminating the sealant layer 150 is improved.

[0054] [Underlayer] An underlayer 150 is formed on the surface of the substrate 100 on which the vapor-deposited film 120 is formed. When the underlayer is a surface resin layer made of a high-melting-point resin material described below, the improved vapor deposition resistance promotes migration of the vapor-deposited material, resulting in a vapor-deposited film consisting of a dense, narrow, and highly flexible continuous layer. Furthermore, because the underlayer is made of a high-melting-point resin material, resistance to heat sterilization treatment is also improved. When the underlayer is an anchor coat layer formed by coating described below, the surface of the substrate is made smoother, promoting migration of the vapor-deposited material and increasing the adhesion strength between the polypropylene substrate and the vapor-deposited film, resulting in a vapor-deposited film consisting of a dense, narrow, and highly flexible continuous layer. These features result in high gas barrier properties and can suppress breakage of the vapor-deposited film and coating layer due to deformation or bending of the film, as well as the resulting deterioration of gas barrier properties. This also results in a barrier film with excellent heat resistance that can withstand heat sterilization treatment.

[0055] (Surface Resin Layer) The underlayer is preferably a surface resin layer. By providing a surface resin layer containing a resin material having a melting point of 180°C or higher (hereinafter also referred to as a high-melting-point resin material) on a polypropylene substrate, a dense vapor-deposited film with few gaps can be formed on the surface resin layer, thereby improving gas barrier properties.

[0056] The melting point of the high-melting-point resin material is more preferably 100°C or higher, even more preferably 180°C or higher, and particularly preferably 200°C or higher. By setting the melting point of the high-melting-point material to 100°C or higher, when the second layer contains a copolymer of propylene and other monomers or modified polypropylene, the second layer can be protected from the vapor deposition material. By setting the melting point of the high-melting-point resin material to 180°C or higher, the density of the vapor deposition film can be improved, and the gas barrier properties can be further improved. Furthermore, the resistance of the laminate to heat sterilization treatment can be further improved. From the viewpoint of film-forming properties, the melting point of the high-melting-point resin material is preferably 265°C or lower, more preferably 260°C or lower, and even more preferably 250°C or lower. Note that, in this specification, the melting point can be measured in accordance with JIS K7121:2012 (Method for measuring transition temperatures of plastics). Specifically, the melting point can be determined by measuring a DSC curve at a heating rate of 10°C / min using a differential scanning calorimetry (DSC) device.

[0057] The difference between the melting point of the high-melting-point resin material contained in the surface resin layer and the melting point of the polypropylene contained in the biaxially oriented polypropylene substrate is preferably 20 to 100°C, more preferably 20 to 70°C. When the melting point difference is 20°C or more, the density of the vapor-deposited film can be further improved, and the gas barrier properties can be further improved. In addition, the resistance of the laminate to heat sterilization treatment can be further improved. When the melting point difference is 100°C or less, the film formability can be further improved.

[0058] The high-melting-point resin material preferably has a polar group. In the present invention, the polar group refers to a group containing one or more heteroatoms, and examples thereof include an ester group, an epoxy group, a hydroxyl group, an amino group, an amide group, a carboxyl group, a carbonyl group, a carboxylic anhydride group, a sulfone group, a thiol group, and a halogen group. Among these, from the viewpoint of the laminate strength of the packaging container, a hydroxyl group, an ester group, an amino group, an amide group, a carboxyl group, and a carbonyl group are preferred, and a hydroxyl group is more preferred.

[0059] The high-melting-point resin material can be used without any particular limitation as long as it has a melting point of 180° C. or higher. Examples of high-melting-point resin materials include vinyl resins, polyamides, polyimides, polyesters, (meth)acrylic resins, cellulose resins, polyolefin resins, and ionomer resins.

[0060] In the present invention, the high-melting-point resin material is particularly preferably a resin material having a melting point of 180°C or higher and having a polar group, and is preferably an ethylene-vinyl alcohol copolymer, polyvinyl alcohol, polyester, or polyamide, more preferably a polyamide such as nylon 6 (hereinafter "nylon" is a registered trademark), nylon 6,6, aromatic-containing nylon, or amorphous nylon. Use of such a resin material can effectively improve the gas barrier properties of the vapor-deposited film formed on the surface resin layer.

[0061] Furthermore, by using polyamide as the high-melting-point resin material, deterioration of gas barrier properties can be suppressed even when the barrier laminate is heated. Polyamides containing benzene rings (aromatic) are preferred as the high-melting-point resin material from the viewpoint of mechanical strength and gas barrier properties. Polyamides containing benzene rings can be combined with other materials for co-extrusion molding. Examples of polyamides containing benzene rings include nylon MXD6 manufactured by Mitsubishi Gas Chemical Company.

[0062] The benzene ring-containing polyamide is a polyamide containing a benzene ring in either or both of the diamine-derived structural units and the dicarboxylic acid-derived structural units. It may be a copolymer of one or more diamines and one or more dicarboxylic acids. It may also be a mixture of two or more copolymers. Examples of the copolymer include a copolymer of a benzene ring-containing diamine and an aliphatic dicarboxylic acid, a copolymer of an aliphatic diamine and a benzene ring-containing dicarboxylic acid, a copolymer of a benzene ring-containing diamine, a benzene ring-containing dicarboxylic acid, and an aliphatic dicarboxylic acid, and a copolymer of an aliphatic diamine, a benzene ring-containing diamine, and a benzene ring-containing dicarboxylic acid.

[0063] The surface resin layer may contain a polyamide that does not contain a benzene ring, or may contain polyester, acrylic resin, ionomer resin, or the like, as long as it does not affect processability and physical properties.

[0064] The diamine containing a benzene ring is metaxylenediamine, paraxylenediamine, metaphenylenediamine, paraphenylenediamine, etc. One or more of these may be used.

[0065] The dicarboxylic acid containing a benzene ring is an aromatic dicarboxylic acid such as terephthalic acid (TPA) or isophthalic acid (IPA), or a naphthalenedicarboxylic acid such as 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, or 2,7-naphthalenedicarboxylic acid. At least one of these is used.

[0066] Aliphatic diamines include linear aliphatic diamines such as 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine (hexamethylenediamine), 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine (NDA), 1,10-decanediamine (DDA), 1,11-undecanediamine, and 1,12-dodecanediamine; 2-methyl-1,8-octanediamine (MODA); 4- Branched-chain aliphatic diamines such as methyl-1,8-octanediamine, 5-methyl-1,9-nonanediamine, 2,2,4- / 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,5-pentanediamine, 2-methyl-1,6-hexanediamine, and 2-methyl-1,7-heptanediamine; alicyclic diamines such as isophoronediamine, norbornanedimethylamine, and tricyclodecanedimethylamine; and the like. At least one of these can be used.

[0067] The aliphatic dicarboxylic acid is an aliphatic dicarboxylic acid having 2 to 20 carbon atoms. In consideration of polymerization suitability and processability, adipic acid is most preferable, but other dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecadioic acid, hexadecadioic acid, eicosanedioic acid, eicosadienedioic acid, and 2,2,4-trimethyladipic acid. One or more of these are used.

[0068] Polyamides that do not contain a benzene ring include polyamides 6, 7, 10, 11, 12, 410, 56, 66, 69, 610, 611, 612, and 1010. The surface resin layer may contain one or more of these.

[0069] The surface resin layer preferably contains 20% by mass or more, more preferably 30% by mass or more, and even more preferably 40% by mass or more of a benzene ring-containing polyamide relative to the entire surface resin layer. By containing 20% ​​by mass or more of a benzene ring-containing polyamide, moist heat swelling can be suppressed, improving adhesion to the vapor-deposited film and reducing the deterioration of the barrier performance of the vapor-deposited film during heat sterilization by boiling or retort. If the content is less than 20% by mass, poor adhesion to the vapor-deposited film and a deterioration of the barrier performance during heat sterilization may occur.

[0070] The surface resin layer preferably contains 20% by mass or more of crystalline polyamide, more preferably 30% by mass or more, and even more preferably 40% by mass or more. By containing 20% ​​by mass or more of crystalline polyamide, gas barrier properties can be improved and moist heat swelling can be suppressed. Examples of crystalline polyamide include a copolymer of metaxylenediamine and adipic acid, a copolymer of hexamethylenediamine and terephthalic acid, and polyamide 6.

[0071] The surface resin layer preferably contains 90% by mass or less of crystalline polyamide, more preferably 80% by mass or less, and even more preferably 70% by mass or less, which allows mixing of an amorphous polyamide, which will be described later.

[0072] The surface resin layer preferably contains 10% by mass or more of amorphous polyamide, more preferably 20% by mass or more, and even more preferably 30% by mass or more. By containing 10% by mass or more of amorphous polyamide, extrusion suitability and stretchability are improved, facilitating the production of the base film 10. Examples of amorphous polyamide include a copolymer of hexamethylenediamine and isophthalic acid, a copolymer of metaxylenediamine and isophthalic acid, a copolymer of hexamethylenediamine and a dicarboxylic acid in which the molar ratio of isophthalic acid / terephthalic acid is 2 / 1, and a copolymer of metaxylenediamine and a dicarboxylic acid in which the molar ratio of adipic acid / isophthalic acid is 1 / 1.

[0073] The surface resin layer preferably contains 80% by mass or less of amorphous polyamide, more preferably 70% by mass or less, and even more preferably 60% by mass or less, which allows mixing of crystalline polyamide.

[0074] The thickness of the surface resin layer is preferably 0.1 μm or more and 5 μm or less, and more preferably 0.2 μm or more and 4 μm or less. By making the thickness of the surface resin layer 0.1 μm or more, the density of the vapor-deposited film can be further improved, and the gas barrier property can be further improved. By making the thickness 5 μm or less, the film-forming property and processability can be further improved.

[0075] The surface resin layer can be formed by melt extrusion. It may be extruded onto a biaxially oriented polypropylene film to form the polypropylene substrate of the present invention, or it may be coextruded with polypropylene in a multilayer structure and then stretched to form the polypropylene substrate of the present invention.

[0076] The underlayer may be an anchor coat layer. The anchor coat layer can be formed by coating a resin material having a polar group. Examples of resin materials having a polar group include ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA), polyester, polyethyleneimine, hydroxyl group-containing (meth)acrylic resin, nylon 6, nylon 6,6, aromatic-containing nylon, amorphous nylon, and polyurethane, with hydroxyl group-containing (meth)acrylic resin, ethylene-vinyl alcohol copolymer, and polyvinyl alcohol being more preferred. As the resin material having a polar group, from the viewpoint of gas barrier properties after heat sterilization treatment due to smoothness and high cohesive energy, a (meth)acrylic resin containing a urethane group and a hydroxyl group is particularly preferred.

[0077] From the viewpoint of adhesion to the vapor-deposited film, it is preferable to add a silane coupling agent to the anchor coat layer, and the silane coupling agents described below can be used as the silane coupling agent.

[0078] In the present invention, the anchor coat layer can be formed using an aqueous emulsion or a solvent-based emulsion. Specific examples of aqueous emulsions include polyamide-based emulsions, polyethylene-based emulsions, and polyurethane-based emulsions, while specific examples of solvent-based emulsions include polyester-based emulsions.

[0079] As the polyurethane emulsion, for example, a mixture of a polyurethane emulsion and an emulsion of an oxazoline group-containing polymer is preferably used. The polyurethane emulsion may further contain a silane coupling agent.

[0080] The thickness of the anchor coat layer is preferably 0.02 μm or more and 10 μm or less, more preferably 0.05 μm or more and 8 μm or less, even more preferably 0.1 μm or more and 5 μm or less, and even more preferably 0.2 μm or more and 3 μm or less. By making the thickness of the anchor coat layer 0.02 μm or more, it is possible to further improve smoothness and gas barrier properties after deposition. By making the thickness of the anchor coat layer 10 μm or less, it is possible to further improve processability and productivity.

[0081] The anchor coat layer may be formed by coating (applying, coating) on ​​a biaxially stretched polypropylene substrate, or may be formed by coating on a polypropylene film and then biaxially stretched.

[0082] [Vapor-deposited film] Next, the vapor-deposited film 120 will be described. The vapor-deposited film contains aluminum oxide, which is an inorganic oxide. In the vapor-deposited film, at least a portion of the aluminum is Al ２ O ３ The deposited film may further contain a metal oxide such as silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, magnesium oxide, titanium oxide, tin oxide, indium oxide, zinc oxide, or zirconium oxide, or a nitride or carbide of these metals.

[0083] The lower limit of the thickness of the vapor-deposited film is preferably 3 nm or more, more preferably 5 nm or more, and the upper limit is preferably 100 nm or less, more preferably 50 nm or less, particularly preferably 15 nm or less.

[0084] In the present invention, the term "aluminum oxide vapor deposition film" means "a vapor deposition film containing aluminum oxide" as described above, and aluminum oxide Al ２ O ３ In addition, aluminum oxide hydroxide AlO(OH) and aluminum hydroxide Al(OH) ３ It may also include the following. This will be explained in detail below.

[0085] (XAFS Spectroscopic Analysis) XAFS analysis is an X-ray Absorption Fine Structure (XAFS) spectrum, in which X-rays are irradiated from the vapor-deposited surface side of the barrier film (or the coating layer side if a coating layer is present) and the amount of absorbed X-rays is measured. Detailed measurement conditions and analysis conditions are described in the Examples.

[0086] In particular, XAFS spectrum analysis of soft X-rays using synchrotron radiation can provide bulk information on the entire deposited film, not just a portion on the surface side, and can provide information on the size of the hydroxyl groups in the aluminum oxide deposited film. Even if a coating layer or the like is present on the surface of the deposited film, information on the deposited film can be obtained even with the coating layer present by irradiating the deposited film from the surface side of the coating layer through the coating layer.

[0087] Fig. 9 shows an example of the results of XAFS measurement of the barrier film of Example 1, which will be described later. Fig. 10 shows the respective peaks obtained by peak separation of the XAFS spectrum in Example 1. In Figs. 9 and 10, the vertical axis represents absorption intensity (a.u) and the horizontal axis represents energy (eV). The peak top ratio P in the present invention is the ratio determined from the respective peak tops after peak separation of the XAFS spectrum, as shown in Fig. 10, for example.

[0088] In the peak separation analysis of Figure 10, "Experiment" is the measured XAFS spectrum, "Fit. Peak 1" is the separated intensity peak at 1566 eV, "Fit. Peak 2" is the separated intensity peak at 1568 eV, and "Fit. Peak 3" is the separated intensity peak at 1572 eV. "Fit. Base 1" is the baseline at 1566 eV, and "Fit. Base 2" is the baseline at 1568 eV.

[0089] 9 and 10, the XAFS spectrum has multiple peaks, specifically, peak P1 with a top near 1566 eV, peak P2 with a top near 1568 eV, and peak P3 with a top near 1572 eV. Note that "near 1566 eV" refers to 1565 eV or more and 1567 eV or less, "near 1568 eV" refers to more than 1567 eV and 1569 eV or less, and "near 1572 eV" refers to 1571 eV or more and 1573 eV or less.

[0090] Here, P1 is considered to be a peak derived from tetracoordinate aluminum oxide, P2 from hexacoordinate aluminum oxide, and P3 from hexacoordinate aluminum hydroxide and aluminum oxide hydroxide.

[0091] Since amorphous aluminum oxide films are thought to have better flexibility than crystalline films, amorphous films are preferred when used as barrier films. However, it has been difficult to determine whether a film is crystalline or amorphous using XRD, a conventional X-ray analysis, except when a clear crystalline peak can be confirmed.

[0092] When XAFS spectra were checked, P1 was detected in the crystalline aluminum oxide film, and γ-Al ２ O ３ and θ-Al ２ O ３ However, the P1 peak never becomes relatively higher than the P2 peak. According to the examples of the present application described later, it is clear that P1>P2, as in Example 1 (see FIG. 10), and it can be confirmed that an amorphous film is formed.

[0093] Furthermore, being amorphous is not enough to ensure a flexible aluminum oxide film; the introduction of hydroxyl groups is considered necessary. However, with conventional depth analysis using TOF-SIMS, for example, it is unclear whether the aluminum oxide film is being evaluated or whether the moisture remaining at the interface between the aluminum oxide film and the substrate is being detected, and when a coating layer is present, sufficient depth resolution cannot be obtained in the aluminum oxide film portion, making it impossible to fully investigate the correlation between film formation conditions and film quality.

[0094] According to the present invention, by checking the XAFS spectrum and defining the peak top ratio P as P3 peak top / P1 peak top=(peak top of intensity near 1572 eV) / (peak top of intensity near 1566 eV), it is possible to obtain information about the amount of hydroxyl groups in the aluminum oxide vapor-deposited film.

[0095] The present invention has discovered that the gas barrier property changes depending on the value of this peak top ratio P. Specifically, by setting the peak top ratio P to be 0.70 or more and less than 1.05, the barrier property after heat sterilization treatment can be maintained. The lower limit of the peak top ratio P is preferably 0.75 or more, more preferably 0.80 or more. The upper limit of the peak top ratio P is preferably 1.00 or less, more preferably 0.90 or less.

[0096] If the peak top ratio P is less than 0.70, the introduction of too few hydroxyl groups results in poor film flexibility and reduced gas barrier properties. Handling and transportability may be impaired, and oxygen barrier properties may be reduced, particularly after retort treatment. If the peak top ratio P is 1.05 or more after high-temperature, high-humidity moist heat treatment or the like, the introduction of too many hydroxyl groups results in reduced initial barrier properties, particularly water vapor barrier properties, resulting in a vapor-deposited film with poor retort resistance.

[0097] The peak-top ratio P of the barrier film can be adjusted by controlling the combination of plasma pretreatment, plasma-assisted treatment during vapor deposition, aging treatment after the film formation process, and aging treatment after the coating layer formation process. In particular, by using a combination that promotes aluminum oxidation through plasma-assisted treatment during vapor deposition and then promotes the introduction of hydroxyl groups through aging treatment after the film formation process, high barrier properties can be obtained even after retort treatment. These results are supported by the examples described below.

[0098] [Coating Layer] The coating layer 130 formed on the vapor-deposited film 120 is a coating layer (barrier coat layer) that protects the vapor-deposited film mechanically and chemically and also improves the barrier performance.

[0099] The coating layer is formed by applying a barrier coating agent to the vapor-deposited film and solidifying it. For example, it may be a cured product of a resin composition containing an alkoxysilane and a hydroxyl-containing water-soluble resin (water-soluble polymer), and optionally containing a silane coupling agent, a sol-gel catalyst, an acid, etc. Other barrier coating agents may be formed using water-based emulsions or solvent-based emulsions.

[0100] Specific examples of water-based emulsions include polyamide-based emulsions, polyethylene-based emulsions, and polyurethane-based emulsions, and specific examples of solvent-based emulsions include polyester-based emulsions.

[0101] As the polyurethane emulsion, for example, a mixture of a polyurethane emulsion and an emulsion of an oxazoline group-containing polymer is preferably used. The polyurethane emulsion may further contain a silane coupling agent.

[0102] The metal alkoxides include those represented by the general formula R1 ｎ M (OR ２ ) ｍ (wherein, R １ , R ２represents an organic group having 1 to 8 carbon atoms, M represents a metal atom, n represents an integer of 0 or more, m represents an integer of 1 or more, and n+m represents the atomic valence of M. Examples of the metal atom represented by M in the metal alkoxide include silicon, zirconium, titanium, aluminum, and the like. For example, it is preferable to use an alkoxysilane in which M is Si.

[0103] The alkoxysilanes mentioned above include, for example, those represented by the general formula Si(ORa) ４ (wherein, Ra represents a lower alkyl group). In the above, Ra may be a methyl group, an ethyl group, an n-propyl group, an n-butyl group, or the like. Specific examples of the alkoxysilane include tetramethoxysilane Si(OCH ３ ) ４ , tetraethoxysilane Si(OC ２ H ５ ) ４ , tetrapropoxysilane Si(OC ３ H ７ ) 4, tetrabutoxysilane Si(OC ４ H ９ ) ４ Two or more of the above alkoxides may be used in combination.

[0104] As the silane coupling agent, those having a reactive group such as a vinyl group, an epoxy group, a methacryl group, or an amino group can be used. In particular, organoalkoxysilanes having an epoxy group are suitable, and for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyldimethylmethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyldimethylethoxysilane, or β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane can be used. The above-mentioned silane coupling agents may be used alone or in combination of two or more.

[0105] In particular, the crosslink density of the cured film of the coating layer using bifunctional compounds such as γ-glycidoxypropylmethyldimethoxysilane and γ-glycidoxypropylmethyldiethoxysilane is lower than that of systems using trialkoxysilanes. As a result, the cured film has excellent gas barrier properties and hot water treatment resistance, while also being flexible and has excellent flex resistance, making it less susceptible to deterioration of gas barrier properties.

[0106] The water-soluble polymer may be a polyvinyl alcohol resin or an ethylene-vinyl alcohol copolymer, either singly or in combination. In the coating layer according to the present embodiment, a polyvinyl alcohol resin is preferred.

[0107] Generally, polyvinyl alcohol resins obtained by saponifying polyvinyl acetate can be used. The polyvinyl alcohol resin may be a partially saponified polyvinyl alcohol resin in which several tens of percent of acetate groups remain, a fully saponified polyvinyl alcohol in which no acetate groups remain, or a modified polyvinyl alcohol resin in which OH groups have been modified. Regarding the degree of saponification of the polyvinyl alcohol resin, it is necessary to use at least one that undergoes crystallization to improve the film hardness of the gas barrier coating film, and preferably has a degree of saponification of 70% or more. Furthermore, any polyvinyl alcohol resin having a degree of polymerization within the range used in conventional sol-gel processes (approximately 100 to 5000) can be used. Examples of such polyvinyl alcohol resins include RS resin "RS-110 (saponification degree = 99%, polymerization degree = 1,000)" manufactured by Kuraray Co., Ltd. and "GOHSENOL NM-14 (saponification degree = 99%, polymerization degree = 1,400)" manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

[0108] The ethylene-vinyl alcohol copolymer may be a saponified copolymer of ethylene and vinyl acetate, i.e., a product obtained by saponifying an ethylene-vinyl acetate random copolymer. For example, it may range from a partially saponified product in which several tens of mole percent of acetate groups remain to a completely saponified product in which only a few mole percent of acetate groups remain, or no acetate groups remain, and is not particularly limited. However, from the viewpoint of barrier properties, the lower limit of the degree of saponification is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more. The upper limit is 100% or less.

[0109] As the catalyst for the sol-gel method, an acid or amine compound is suitable.

[0110] Examples of acids that can be used include mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid, and organic acids such as acetic acid and tartaric acid.

[0111] The acid content is preferably 0.001 to 0.05 mol %, more preferably 0.01 to 0.03 mol %, based on the total molar amount of alkoxy groups in the metal alkoxide. If the acid content is less than 0.001 mol %, the catalytic effect is too small, whereas if the acid content is more than 0.05 mol %, the catalytic effect is too strong, causing the reaction rate to become too fast and tending to become non-uniform.

[0112] As the amine compound, a tertiary amine that is substantially insoluble in water and soluble in an organic solvent is preferred. Specifically, for example, N,N-dimethylbenzylamine, tripropylamine, tributylamine, tripentylamine, etc. can be used. N,N-dimethylbenzylamine is particularly preferred.

[0113] The content of the amine compound is preferably, for example, 0.01 to 1.0 part by mass, particularly 0.03 to 0.3 part by mass, per 100 parts by mass of the metal alkoxide. If the content is less than 0.01 part by mass, the catalytic effect is too small, whereas if the content is more than 1.0 part by mass, the catalytic effect is too strong, causing the reaction rate to become too fast and tending to become non-uniform.

[0114] As the solvent, it is preferable to use water or alcohol such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropanol, or n-butanol.

[0115] The barrier coating layer formed as described above has a thickness of 100 to 500 nm, preferably 200 to 400 nm, which is preferable because the coating film does not crack and the surface of the deposited film is sufficiently coated.

[0116] When the barrier coating agent contains a silane coupling agent, it can contain 5 to 10 parts by mass of a water-soluble polymer such as a polyvinyl alcohol resin and 1 to 10 parts by mass of the silane coupling agent per 100 parts by mass of alkoxysilane. This allows the film to maintain its flexibility. In the above case, using more than 20 parts by mass of the silane coupling agent is undesirable, as it increases the rigidity and brittleness of the barrier coating film formed.

[0117] Furthermore, when a silane coupling agent is not contained, the ratio of the metal alkoxide can be reduced and the barrier property can be improved by using 10 to 20 parts by mass of a water-soluble polymer such as a polyvinyl alcohol resin per 100 parts by mass of alkoxysilane.

[0118] In the coating layer, the ratio of SiO of a metal alkoxide such as tetraethoxysilane to the mass of a water-soluble resin such as polyvinyl alcohol ２ The lower limit of the mass ratio in terms of converted mass is preferably 1.6 or more, more preferably 1.9 or more. The upper limit is preferably 3.9 or less, more preferably 3.5 or less. A ratio of more than 3.9 is not preferred because the barrier properties may be reduced in later processes, and a ratio of less than 1.6 is not preferred because the barrier properties after retort treatment are reduced.

[0119] The silicon atom to carbon atom ratio (Si / C) of the coating layer is preferably 1.30 or more and 1.65 or less. If it exceeds 1.65, the barrier properties may be reduced in subsequent processes, etc., which is not preferred, and if it is less than 1.30, the barrier properties after heat sterilization treatment will be reduced, which is not preferred. The silicon atom to carbon atom ratio of the coating layer can be measured by X-ray photoelectron spectroscopy (XPS), specifically under the conditions described in the Examples.

[0120] (Film Forming Apparatus) Next, an example of a film forming apparatus 10 used in the method for manufacturing a barrier film will be described. As shown in Fig. 2, the film forming apparatus 10 includes a substrate transport mechanism 11A for transporting the substrate 1, a plasma pretreatment mechanism 11B for performing plasma pretreatment on the surface of the substrate 1, and a film forming mechanism 11C for forming a vapor-deposited film 2. In the example shown in Fig. 5, the film forming apparatus 10 further includes a decompression chamber 12. The decompression chamber 12 has a decompression mechanism, such as a vacuum pump described below, that adjusts the atmosphere in at least a part of the space inside the decompression chamber 12 to atmospheric pressure or below.

[0121] 2, the decompression chamber 12 includes a substrate transport chamber 12A in which the substrate transport mechanism 11A is located, a plasma pretreatment chamber 12B in which the plasma pretreatment mechanism 11B is located, and a film deposition chamber 12C in which the film deposition mechanism 11C is located. The decompression chamber 12 is preferably configured to prevent the atmospheres inside each chamber from mixing with each other. For example, as shown in FIG. 2, the decompression chamber 12 may be located between the substrate transport chamber 12A and the plasma pretreatment chamber 12B, between the plasma pretreatment chamber 12B and the film deposition chamber 12C, and between the substrate transport chamber 12A and the film deposition chamber 12C, and may have partition walls 35a to 35c separating the chambers.

[0122] The substrate transfer chamber 12A, the plasma pretreatment chamber 12B, and the film formation chamber 12C will now be described. The plasma pretreatment chamber 12B and the film formation chamber 12C are each provided adjacent to the substrate transfer chamber 12A and each have a portion connecting to the substrate transfer chamber 12A. This allows the substrate 1 to be transferred between the substrate transfer chamber 12A and the plasma pretreatment chamber 12B, and between the substrate transfer chamber 12A and the film formation chamber 12C without being exposed to the atmosphere. For example, between the substrate transfer chamber 12A and the plasma pretreatment chamber 12B, the substrate 1 can be transferred through an opening provided in the partition wall 35a. The same structure is also provided between the substrate transfer chamber 12A and the film formation chamber 12C, allowing the substrate 1 to be transferred between the substrate transfer chamber 12A and the film formation chamber 12C.

[0123] The function of the decompression mechanism of the decompression chamber 12 will now be described. The decompression mechanism of the decompression chamber 12 is configured to be able to decompress the atmosphere in the space in which at least the plasma pretreatment mechanism 11B or the film formation mechanism 11C of the film formation apparatus 10 is disposed to below atmospheric pressure. The decompression mechanism may be configured to be able to decompress the pressure in each of the substrate transfer chamber 12A, the plasma pretreatment chamber 12B, and the film formation chamber 12C, which are partitioned by partition walls 35a to 35c, to below atmospheric pressure.

[0124] The configuration of the decompression mechanism of the decompression chamber 12 will be described. The decompression chamber 12 may have, for example, a vacuum pump connected to the plasma pretreatment chamber 12B. By adjusting the vacuum pump, the pressure inside the plasma pretreatment chamber 12B can be appropriately controlled when performing the plasma pretreatment described below. Furthermore, the method described below can prevent the plasma supplied into the plasma pretreatment chamber 12B from diffusing to other chambers. The decompression mechanism of the decompression chamber 12 may have a vacuum pump connected to the film formation chamber 12C, similar to the vacuum pump connected to the plasma pretreatment chamber 12B. The vacuum pump may be a dry pump, a turbomolecular pump, a cryopump, a rotary pump, a diffusion pump, or the like.

[0125] A substrate transport mechanism 11A for the substrate 1 of the film formation apparatus 10 according to this embodiment will be described together with the transport path of the substrate 1. The substrate transport mechanism 11A is a mechanism for transporting the substrate 1, disposed in the substrate transport chamber 12A. In the example shown in FIG. 2, the substrate transport mechanism 11A includes an unwinding roller 13 to which a roll of the substrate 1 is attached, a take-up roller 15 that winds up the substrate 1, and guide rolls 14a to 14d. The substrate 1 sent out from the substrate transport mechanism 11A is then transported by a pretreatment roller 20 (described later) disposed in the plasma pretreatment chamber 12B and a film formation roller 25 (described later) disposed in the film formation chamber 12C.

[0126] Although not shown, the substrate conveying mechanism 11A may further include a tension pickup roller. By including the tension pickup roller in the substrate conveying mechanism 11A, the substrate 1 can be conveyed while adjusting the tension applied to the substrate 1.

[0127] (Plasma Pretreatment Mechanism) The plasma pretreatment mechanism 11B will be described. The plasma pretreatment mechanism 11B is a mechanism for performing plasma pretreatment on the surface of the substrate 1. The plasma pretreatment mechanism 11B shown in FIG. 2 generates plasma P and performs plasma pretreatment on the surface of the substrate 1 using the generated plasma P. When the surface of the substrate 1 is activated by plasma pretreatment, for example, hydrogen is released from the substrate resin component to generate carbon radicals. These radicals then bond with oxygen and hydrogen in the atmosphere to generate functional groups such as hydroxyl groups, carboxyl groups, and ketone groups. The generation of such functional groups is thought to improve the adhesion between the substrate 1 and the vapor-deposited film 2. The plasma pretreatment mechanism 11B shown in FIG. 2 includes a pretreatment roller 20 arranged in the plasma pretreatment chamber 12B, an electrode unit 21 facing the pretreatment roller 20, and a magnetic field generating unit 23 that generates a magnetic field between the pretreatment roller 20 and the electrode unit 21.

[0128] The pretreatment roller 20 will now be described. FIG. 3 is an enlarged view of the area surrounded by the dashed line marked with the symbol VI in FIG. 2. Note that FIG. 3 omits the power supply wiring 31 connecting the power source 32 shown in FIG. 2 to the electrode unit 21 described later, and the plasma P generated by the plasma pretreatment mechanism 11B. The pretreatment roller 20 has a rotation axis X. The pretreatment roller 20 is arranged so that at least the rotation axis X is located within the plasma pretreatment chamber 12B, which is partitioned by partition walls 35a and 35b. A substrate 1 having a dimension in the direction of the rotation axis X is wrapped around the pretreatment roller 20. In the following description, the dimension of the substrate 1 in the direction of the rotation axis X is also referred to as the width of the substrate 1. The direction of the rotation axis X is also referred to as the width direction of the substrate 1.

[0129] As shown in Fig. 2, the pretreatment roller 20 may be provided so that a portion thereof is exposed on the substrate transport chamber 12A side. In the example shown in Fig. 2, the plasma pretreatment chamber 12B and the substrate transport chamber 12A are connected via an opening provided in the partition wall 35a, and a portion of the pretreatment roller 20 is exposed on the substrate transport chamber 12A side through this opening. A gap is provided between the partition wall 35a between the substrate transport chamber 12A and the plasma pretreatment chamber 12B and the pretreatment roller 20, and the substrate 1 can be transported from the substrate transport chamber 12A to the plasma pretreatment chamber 12B through this gap. Although not shown, the pretreatment roller 20 may be provided so that its entirety is located within the plasma pretreatment chamber 12B.

[0130] Although not shown, the pretreatment roller 20 may have a temperature adjustment mechanism that adjusts the temperature of the surface of the pretreatment roller 20. For example, the pretreatment roller 20 may have a temperature adjustment mechanism inside the pretreatment roller 20 that includes piping for circulating a temperature adjustment medium such as a refrigerant or a heat medium. The temperature adjustment mechanism adjusts the surface temperature of the pretreatment roller 20 to a target temperature within a range of, for example, −20° C. or higher and 100° C. or lower.

[0131] By providing the pretreatment roller 20 with a temperature adjustment mechanism, shrinkage or damage to the substrate 1 due to heat during plasma pretreatment can be suppressed.

[0132] The pretreatment roller 20 is formed from a material containing at least one of stainless steel, iron, copper, and chromium. The surface of the pretreatment roller 20 may be treated with a hard chromium hard coat to prevent scratches. These materials are easy to process. Furthermore, using the above materials for the pretreatment roller 20 increases the thermal conductivity of the pretreatment roller 20 itself, making it easier to control the temperature of the pretreatment roller 20.

[0133] The electrode unit 21 will now be described. In the example shown in FIGS. 2 and 3, the electrode unit 21 has a first surface 21c facing the pretreatment roller 20 and a second surface 21d located on the opposite side of the first surface 21c. In the example shown in FIGS. 2 and 3, the electrode unit 21 is a plate-shaped member, and both the first surface 21c and the second surface 21d are flat. The electrode unit 21 generates plasma between itself and the pretreatment roller 20 by applying an AC voltage between itself and the pretreatment roller 20. The electrode unit 21 preferably forms an electric field between itself and the pretreatment roller 20 such that the generated plasma moves perpendicular to the surface of the substrate 1 and toward the surface of the substrate 1. This allows the substrate 1 to be pretreated efficiently.

[0134] The number of electrode units 21 is preferably two or more. The two or more electrode units 21 are preferably arranged along the transport direction of the substrate 1. In the examples shown in Figures 2 and 3, the film forming apparatus 10 has two electrode units 21. The number of electrode units 21 is, for example, 12 or less.

[0135] The effect of two or more electrode units 21 arranged along the transport direction of the substrate 1 will be described. As described above, plasma is generated between the electrode unit 21 and the pretreatment roller 20. The area in which plasma is generated expands as the dimension of the electrode unit 21 in the transport direction increases. On the other hand, when the electrode unit 21 is a flat, plate-shaped member, the larger the dimension of the electrode unit 21 in the transport direction, the greater the distance from the end of the first surface 21c of the electrode unit 21, which is the surface facing the pretreatment roller 20, to the pretreatment roller 20 in the transport direction, which reduces the processing ability of the plasma.

[0136] In the film forming apparatus 10, two or more electrode units 21 are arranged along the transport direction of the substrate 1. Therefore, even if the dimensions of the electrode units 21 in the transport direction of the substrate 1 are small, plasma can be generated over a wide range in the transport direction. Furthermore, by reducing the dimensions of the electrode units 21, the distance from the end of the first surface 21c of the electrode units 21 to the pretreatment roller 20 in the transport direction can be reduced, and plasma can be generated uniformly in the transport direction.

[0137] As shown in FIGS. 2 and 3 , the electrode unit 21 has a first end 21e and a second end 21f located on the first surface 21c of the electrode unit 21. The first end 21e is the upstream end in the transport direction of the substrate 1, and the second end 21f is the downstream end in the transport direction of the substrate 1. As described above, by reducing the dimension of the electrode unit 21 in the transport direction of the substrate 1, the distance from the first end 21e and the second end 21f of the electrode unit 21 to the pretreatment roller 20 in the transport direction can be reduced. The dimension of the electrode unit 21 in the transport direction of the substrate 1 corresponds to the angle θ shown in FIG. 3 . The angle θ is the angle formed between a line passing through the first end 21e and the rotation axis X and a line passing through the second end 21f and the rotation axis X. The angle θ is preferably 20° or more and 90° or less, more preferably 60° or less, and even more preferably 45° or less. By setting the angle θ within the above range, plasma can be generated uniformly in the transport direction between the electrode unit 21 and the pretreatment roller 20 when the first surface 21c of the electrode unit 21 is flat.

[0138] There are no particular limitations on the material of the electrode portion 21 as long as it is conductive. Specifically, aluminum, copper, and stainless steel are preferably used as the material of the electrode portion 21.

[0139] The thickness L3 of the electrode unit 21 when viewed in a direction perpendicular to the first surface 21c of the electrode unit 21 is not particularly limited, but is, for example, 15 mm or less. When the thickness of the electrode unit 21 is the above value, the magnetic field generating unit 23 can effectively generate a magnetic field between the pretreatment roller 20 and the electrode unit 21. Furthermore, the thickness L3 of the electrode unit 21 is, for example, 3 mm or more.

[0140] The magnetic field forming unit 23 will now be described. As shown in FIGS. 2 and 3 , the magnetic field forming unit 23 is provided on the side of the electrode unit 21 opposite the side facing the pretreatment roller 20. The magnetic field forming unit 23 is a member that forms a magnetic field between the pretreatment roller 20 and the electrode unit 21. The magnetic field between the pretreatment roller 20 and the electrode unit 21 contributes to the generation of higher density plasma, for example, when plasma is generated using the plasma pretreatment mechanism 11B. The magnetic field forming unit 23 shown in FIGS. 2 and 3 has a first magnet 231 and a second magnet 232 provided on the second surface 21 d of the electrode unit 21.

[0141] The number of magnetic field forming units 23 is preferably 2 or more. When the plasma pretreatment mechanism 11B has two or more electrode units 21 and two or more magnetic field forming units 23, each of the two or more magnetic field forming units 23 is preferably provided on the side of each of the two or more electrode units 21 opposite the side facing the pretreatment roller 20. In the example shown in Figures 2 and 3, each of the two magnetic field forming units 23 is provided on the second surface 21d of each of the two electrode units 21.

[0142] The structure of the first magnet 231 and the second magnet 232 in the normal direction of the second surface 21d of the electrode unit 21 will be described. As shown in FIGS. 2 and 3, the first magnet 231 and the second magnet 232 each have a north pole and a south pole. The symbol N in FIGS. 2 and 3 indicates the north pole of the first magnet 231 or the second magnet 232. The symbol S in FIGS. 2 and 3 indicates the south pole of the first magnet 231 or the second magnet 232. One of the north pole or south pole of the first magnet 231 is located closer to the substrate 1 than the other. The other of the north pole or south pole of the second magnet 232 is located closer to the substrate 1 than the other. In the example shown in FIGS. 2 and 3, the north pole of the first magnet 231 is located closer to the substrate 1 than the south pole of the first magnet 231, and the south pole of the second magnet 232 is located closer to the substrate 1 than the north pole of the second magnet. Although not shown in the figure, the south pole of the first magnet 231 may be located closer to the substrate 1 than the north pole of the first magnet 231, and the north pole of the second magnet 232 may be located closer to the substrate 1 than the south pole of the second magnet 232.

[0143] Next, the structure of the first magnet 231 and the second magnet 232 in the planar direction of the second surface 21d of the electrode unit 21 will be described. Fig. 4 is a plan view of the electrode unit 21 and magnetic field generating unit 23 shown in Fig. 2, viewed from the magnetic field generating unit 23 side. Fig. 5 is a cross-sectional view showing a cross section taken along line VIII-VIII in Fig. 4. In Fig. 4, direction D1 is the direction in which the rotation axis X of the pre-treatment roller 20 extends.

[0144] As shown in Figures 4 and 5, the first magnet 231 has a first axial portion 231c. As shown in Figure 4, the first axial portion 231c extends along direction D1, i.e., along the rotation axis X of the pre-treatment roller 20. The first magnet 231 provided on one electrode unit 21 may have one first axial portion 231c, or may have two or more first axial portions 231c. In the example shown in Figure 4, the first magnet 231 provided on one electrode unit 21 has one first axial portion 231c.

[0145] 4 and 5, the second magnet 232 has a second axial portion 232c. As shown in Fig. 4, the second axial portion 232c also extends along the direction D1, i.e., along the rotation axis X, similar to the first axial portion 231c.

[0146] Since both the first magnet 231 and the second magnet 232 include a portion extending along the rotation axis X, it is possible to increase the uniformity in the width direction of the substrate 1 of the strength of the magnetic field formed around the substrate 1. This makes it possible to increase the uniformity in the width direction of the substrate 1 of the distribution density of the plasma formed around the substrate 1.

[0147] The second magnet 232 provided on one electrode unit 21 may have one second axial portion 232c or two or more second axial portions 232c. In the example shown in Figures 4 and 5, the second magnet 232 provided on one electrode unit 21 has two second axial portions 232c. The two second axial portions 232c may be positioned so as to sandwich the first axial portion 231c in the direction D2 perpendicular to the rotation axis X in the planar direction of the second surface 21d of the electrode unit 21.

[0148] 5, the dimension L4 of the first axial portion 231c and the dimension L5 of the second axial portion 232c in the conveyance direction of the substrate 1 are not particularly limited. Furthermore, the ratio between the dimension L4 of the first axial portion 231c and the dimension L5 of the second axial portion 232c in the conveyance direction of the substrate 1 is not particularly limited. The dimension L4 of the first axial portion 231c and the dimension L5 of the second axial portion 232c may be equal, or the dimension L4 of the first axial portion 231c may be larger than the dimension L5 of the second axial portion 232c.

[0149] The distance L6 between the first axial portion 231c and the second axial portion 232c in the direction D2 is set so that a magnetic field generated by the first axial portion 231c and the second axial portion 232c is formed between the pre-treatment roller 20 and the electrode portion 21.

[0150] The second magnet 232 may surround the first magnet 231 when the magnetic field generating unit 23 is viewed along the normal direction of the second surface 21d of the electrode unit 21. For example, as shown in Fig. 4, the second magnet 232 may have two second axial portions 232c and two connecting portions 232d provided to connect the two second axial portions 232c.

[0151] Examples of the types of magnets used as the magnetic field generating unit 23, such as the first magnet 231 and the second magnet 232, include permanent magnets such as ferrite magnets and rare earth magnets such as neodymium and samarium cobalt (samarium-cobalt). Alternatively, an electromagnet can be used as the magnetic field generating unit 23.

[0152] The magnetic flux density of the magnets of the magnetic field generating unit 23, such as the first magnet 231 and the second magnet 232, is, for example, 100 Gauss or more and 10,000 Gauss or less. If the magnetic flux density is 100 Gauss or more, a sufficiently strong magnetic field is formed between the pretreatment roller 20 and the electrode unit 21, thereby generating a sufficiently high-density plasma and enabling a good pretreatment surface to be formed at high speed. On the other hand, to increase the magnetic flux density on the surface of the substrate 1 to more than 10,000 Gauss, an expensive magnet or magnetic field generating mechanism is required.

[0153] Although not shown, the plasma pretreatment mechanism 11B may have a plasma raw material gas supply unit. The plasma raw material gas supply unit supplies a plasma raw material gas into the plasma pretreatment chamber 12B. The configuration of the plasma raw material gas supply unit is not particularly limited. For example, the plasma raw material gas supply unit may be provided on the wall surface of the plasma pretreatment chamber 12B and include a hole for ejecting the plasma raw material gas. The plasma raw material gas supply unit may also have a nozzle for ejecting the plasma raw material gas at a position closer to the substrate 1 than the wall surface of the plasma pretreatment chamber 12B. The plasma raw material gas supplied by the plasma raw material gas supply unit may be, for example, an inert gas such as argon, an active gas such as oxygen, nitrogen, carbon dioxide, or ethylene, or a mixture of these gases. As the plasma raw material gas, a single inert gas, a single active gas, or a mixture of two or more gases contained in the inert gas or active gas may be used. As the plasma raw material gas, a mixture of an inert gas such as argon and an active gas may be used. As an example, the plasma raw material gas supply unit may be a gas supplying unit that supplies argon (Ar) and oxygen (O ２ ) mixed gas is supplied.

[0154] The plasma pretreatment mechanism 11B has a plasma density of, for example, 100 W·sec / m ２ More than 8000W・sec / m ２ The following plasma is supplied between the pretreatment roller 20 and the electrode unit 21.

[0155] 2, the plasma pretreatment mechanism 11B is disposed in a plasma pretreatment chamber 12B, which is separated by a partition wall from the substrate transport chamber 12A and the film formation chamber 12C. By separating the plasma pretreatment chamber 12B from other areas, such as the substrate transport chamber 12A and the film formation chamber 12C, it becomes easier to adjust the atmosphere in the plasma pretreatment chamber 12B independently. This makes it easier to control the plasma raw material gas concentration in the space where the pretreatment roller 20 and the electrode unit 21 face each other, improving the productivity of laminated films.

[0156] (Film Forming Mechanism) Next, the film forming mechanism 11C will be described. In the example shown in Fig. 2, the film forming mechanism 11C has a film forming roller 25 and an evaporation mechanism 24 disposed in the film forming chamber 12C.

[0157] The film-forming roller 25 will be described. The film-forming roller 25 is a roller that wraps around and transports the substrate 1 with the treated surface of the substrate 1 that has been pretreated in the plasma pretreatment mechanism 11B facing outward.

[0158] The material of the film-forming roller 25 will now be described. The film-forming roller 25 is preferably formed from a material containing at least one of stainless steel, iron, copper, and chromium. The surface of the film-forming roller 25 may be treated with a hard chromium hard coat to prevent scratches. These materials are easy to process. Furthermore, by using the above-mentioned materials for the film-forming roller 25, the thermal conductivity of the film-forming roller 25 itself is increased, resulting in excellent temperature controllability during temperature control. The average surface roughness Ra of the surface of the film-forming roller 25 is, for example, 0.1 μm or more and 10 μm or less.

[0159] Although not shown, the film-forming roller 25 may also have a temperature adjustment mechanism for adjusting the surface temperature of the film-forming roller 25. The temperature adjustment mechanism may, for example, have a circulation path for circulating a cooling medium or a heat source medium inside the film-forming roller 25. The cooling medium (refrigerant) may be, for example, an ethylene glycol aqueous solution, and the heat source medium (heat medium) may be, for example, silicone oil. The temperature adjustment mechanism may also have a heater installed in a position opposite the film-forming roller 25. When the film-forming mechanism 11C forms a film by vapor deposition, in consideration of the heat resistance constraints of related mechanical components and versatility, the temperature adjustment mechanism preferably adjusts the surface temperature of the film-forming roller 25 to a target temperature within a range of -20°C to 200°C. By having the film-forming roller 25 have a temperature adjustment mechanism, fluctuations in the temperature of the substrate 1 due to heat generated during film formation can be suppressed.

[0160] The evaporation mechanism 24 will now be described. FIG. 6 is an enlarged view of the area enclosed by the dashed line designated by the symbol IX in FIG. 2 , showing a specific configuration of the evaporation mechanism 24 (omitted in FIG. 5 ) and a diagram showing the evaporation material supply unit 61 (omitted in FIG. 2 ) for supplying the evaporation material. Note that the decompression chamber 12 and partition walls 35b and 35c are omitted from FIG. 6 . The evaporation mechanism 24 evaporates the evaporation material containing aluminum. The evaporated evaporation material adheres to the substrate 1, thereby forming an aluminum-containing evaporation film on the surface of the substrate 1. The evaporation mechanism 24 in this embodiment employs a resistance heating system. In the example shown in FIG. 6 , the evaporation mechanism 24 includes a boat 24b. In this embodiment, the boat 24b includes a power supply (not shown) and a resistor (not shown) electrically connected to the power supply. A plurality of boats 24b may be arranged in the width direction of the substrate 1.

[0161] 6, the film forming mechanism 11C may have a vapor deposition material supply unit 61 that supplies a vapor deposition material to the evaporation mechanism 24. In FIG. 6, an example is shown in which the vapor deposition material supply unit 61 continuously feeds out an aluminum metal wire.

[0162] Although not shown, the film formation mechanism 11C has a gas supply mechanism. The gas supply mechanism is a mechanism that supplies gas between the evaporation mechanism 24 and the film formation roller 25. The gas supply mechanism supplies at least oxygen gas. The oxygen gas reacts with or bonds with an evaporation material such as aluminum that evaporates from the evaporation mechanism 24 and heads toward the substrate 1 on the film formation roller 25. This allows a vapor deposition film containing aluminum oxide to be formed on the surface of the substrate 1.

[0163] The film formation mechanism 11C also includes a plasma supply mechanism 50 that supplies plasma between the surface of the substrate 1 and the evaporation mechanism 24. In the examples shown in FIGS. 2 and 6 , the plasma supply mechanism 50 has a hollow cathode 51. In this embodiment, the hollow cathode 51 is a cathode having a hollow portion that is partially open. The hollow cathode 51 can generate plasma within the hollow portion. In the example shown in FIG. 6 , the hollow cathode 51 is disposed so that the opening of the hollow portion of the hollow cathode 51 is positioned diagonally above the boat 24b. Although not shown, the plasma supply mechanism 50 according to this embodiment also includes an anode facing the opening, which extracts plasma from the opening of the hollow cathode 51. The plasma supply mechanism 50 according to this embodiment generates plasma within the hollow portion of the hollow cathode 51 and extracts the plasma between the surface of the substrate 1 and the evaporation mechanism 24 using the opposing anode, thereby generating a strong plasma between the surface of the substrate 1 and the evaporation mechanism 24. The position of the opposing anodes is not particularly limited as long as the opposing anodes can extract plasma from the opening of the cavity of the hollow cathode 51 and supply plasma between the surface of the substrate 1 and the evaporation mechanism 24. In this embodiment, a case will be described in which the opposing anodes are arranged on both sides of the boat 24b in the width direction of the substrate 1. In this case, the film formation mechanism 11C has a plurality of boats 24b and a plurality of opposing anodes, and the plurality of boats 24b and the plurality of opposing anodes may be arranged alternately in the width direction of the substrate 1. Although not shown, the plasma supply mechanism 50 may have a raw material supply device that supplies a plasma raw material gas at least into the cavity of the hollow cathode 51. The plasma raw material gas supplied by the raw material supply device may be, for example, the same gas as the plasma raw material gas supplied by the plasma raw material gas supply unit of the plasma pretreatment mechanism 11B.

[0164] By using the plasma supply mechanism 50 to supply plasma between the surface of the substrate 1 and the evaporation mechanism 24, plasma assist during deposition can be performed, activating the aluminum and oxygen gas evaporated in the evaporation mechanism 24 and promoting the reaction or bonding between the aluminum and oxygen gas. This can increase the proportion of aluminum present as aluminum oxide in the evaporated film 2 formed on the surface of the substrate 1, and stabilize the properties of the evaporated film 2.

[0165] Although not shown, the film forming apparatus 10 may include a substrate charge removal unit in the substrate transport chamber 12A, located downstream of the film formation chamber 12C in the transport direction of the substrate 1. The substrate charge removal unit performs post-processing to remove charge generated on the substrate 1 due to film formation by the film formation mechanism 11C. The substrate charge removal unit may be provided to remove charge from one side of the substrate 1, or may be provided to remove charge from both sides of the substrate 1.

[0166] The device used as the substrate charge removal unit for performing post-treatment on the substrate 1 is not particularly limited, but examples thereof include a plasma discharge device, an electron beam irradiation device, an ultraviolet irradiation device, a static elimination bar, a glow discharge device, and a corona treatment device.

[0167] When post-treatment is performed by forming a discharge using a plasma treatment device or a glow discharge device, a discharge gas such as argon, oxygen, nitrogen, or helium, or a mixture of these, is supplied near the substrate 1, and post-treatment can be performed using any discharge method such as alternating current (AC) plasma, direct current (DC) plasma, arc discharge, microwave, or surface wave plasma. In a reduced pressure environment, it is most preferable to perform post-treatment using a plasma discharge device.

[0168] The substrate charge removal unit is installed in a portion of the substrate transport chamber 12A that is located downstream of the film-forming chamber 12C in the transport direction of the substrate 1, and by removing the charge from the substrate 1, the substrate 1 can be transported by quickly separating it from the film-forming roller 25 at a predetermined position. This enables stable substrate transport, prevents damage to the substrate 1 or deterioration in quality due to charging, and improves post-processing suitability by improving the wettability of the front and back surfaces of the substrate.

[0169] (Power Supply) In the example shown in FIG. 2 , the film forming apparatus 10 further includes a power supply 32 electrically connected to the pretreatment roller 20 and the electrode unit 21. In the example shown in FIG. 5 , the power supply 32 is electrically connected to the pretreatment roller 20 and the electrode unit 21 via power supply wiring 31. The power supply 32 is, for example, an AC power supply. When the power supply 32 is an AC power supply, the power supply 32 can apply an AC voltage having a frequency of, for example, 20 kHz to 500 kHz between the pretreatment roller 20 and the electrode unit 21. The input power that can be applied by the power supply 32 (the power that can be applied per 1 m width of the electrode unit 21 in the width direction of the substrate 1) is not particularly limited, but is, for example, 0.5 kW / m to 20 kW / m. The pretreatment roller 20 may be installed at an electrically earth level or at an electrically floating level.

[0170] (Method for manufacturing a barrier film) Next, a method for manufacturing the barrier film shown in FIG. 1 using the above-mentioned film formation apparatus 10 will be described. First, a film formation method for forming a vapor-deposited film 2 on the surface of a substrate 1 will be described. In film formation using the film formation apparatus 10, a plasma pretreatment step of performing plasma pretreatment on the surface of the substrate 1 using the plasma pretreatment mechanism 11B and a film formation step of forming a vapor-deposited film on the surface of the substrate 1 using the film formation mechanism 11C are performed while the substrate 1 is transported along the above-mentioned transport path of the substrate 1. The transport speed of the substrate 1 is preferably 200 m / min or more, and more preferably 400 m / min or more and 1000 m / min or less.

[0171] (Plasma Pretreatment Step) The plasma pretreatment step is performed, for example, by the following method. First, a plasma raw material gas is supplied into the plasma pretreatment chamber 12B. Next, the above-mentioned AC voltage is applied between the pretreatment roller 20 and the electrode unit 21. When applying the AC voltage, input power control, impedance control, or the like may be performed.

[0172] The plasma raw material gas supplied in the pretreatment is oxygen alone or a mixture of oxygen gas and an inert gas, which is supplied from a gas reservoir through a flow rate controller while the flow rate of the gas is measured. The inert gas may be one or a mixture of two or more gases selected from the group consisting of argon, helium, and nitrogen.

[0173] In the plasma treatment, the mixing ratio of oxygen gas to the inert gas, that is, oxygen gas / inert gas, is preferably 6 / 1 to 1 / 1, and more preferably 5 / 2 to 3 / 2.5.

[0174] By setting the mixing ratio to 6 / 1 to 1 / 1, the film formation energy of the vapor-deposited aluminum on the resin substrate increases, and by setting the ratio to 5 / 2 to 3 / 2, the oxidation degree of the aluminum oxide vapor-deposited film is increased, thereby ensuring adhesion between the aluminum oxide vapor-deposited film and the substrate.

[0175] Application of AC voltage generates plasma simultaneously with glow discharge, and plasma P becomes denser between pretreatment roller 20 and magnetic field forming unit 23. In this way, plasma P can be supplied between pretreatment roller 20 and magnetic field forming unit 23. This plasma P can be used to perform plasma (ion) pretreatment on the surface of substrate 1.

[0176] Plasma intensity per unit area in plasma processing: 50 W·sec / m ２ More than 8000W・sec / m ２ less than 50 W·sec / m ２ Below this, the effect of plasma pretreatment is not observed, and ２ Above this level, the resin substrate tends to be deteriorated by the plasma, such as worn, damaged, discolored, and burned. In particular, the plasma intensity for plasma pretreatment to form an aluminum oxide layer should be 100 W·sec / m ２ More than 1000W・sec / m ２ The following is preferred:

[0177] The pressure inside plasma pretreatment chamber 12B when an AC voltage is applied between pretreatment roller 20 and electrode unit 21 is reduced to below atmospheric pressure by decompression chamber 12. In this case, the pressure inside plasma pretreatment chamber 12B is adjusted, for example, so that the application of AC voltage can cause a glow discharge between pretreatment roller 20 and electrode unit 21. The pressure inside plasma pretreatment chamber 12B when an AC voltage is applied between pretreatment roller 20 and electrode unit 21 can be set and maintained at approximately 0.1 Pa or more and 100 Pa or less, and a pressure of 1 Pa or more and 20 Pa or less is particularly preferred.

[0178] The function of the magnetic field generating unit 23 in the plasma pretreatment step will now be described. The magnetic field generating unit 23 generates a magnetic field between the pretreatment roller 20 and the electrode unit 21. The magnetic field can act to capture and accelerate electrons present between the pretreatment roller 20 and the electrode unit 21. This increases the frequency of collisions between electrons and the plasma raw material gas in the region where the magnetic field is generated, thereby increasing and localizing the plasma density and improving the efficiency of the plasma pretreatment.

[0179] (Film Forming Process) In the film forming process, a film is formed on the surface of the substrate 1 using the film forming mechanism 11C. As an example of the film forming process, a case where an aluminum oxide vapor deposition film is formed using the film forming mechanism 11C having the evaporation mechanism 24 shown in FIG.

[0180] First, an evaporation material containing aluminum is supplied into the boat 24b of the evaporation mechanism 24 so as to face the deposition roller 25. An aluminum metal wire rod can be used as the evaporation material. In the example shown in FIG. 6 , the evaporation material is supplied to the boat 24b by continuously feeding the aluminum metal wire rod into the boat 24b using an evaporation material supply unit 61.

[0181] The aluminum is evaporated in the boat 24b by heating. For convenience, FIG. 6 illustrates evaporated aluminum vapor 63. The oxygen gas that oxidizes the aluminum may be supplied as oxygen alone or as a mixed gas with an inert gas such as argon. By controlling the amount of oxygen, both barrier properties and transparency can be achieved. The pressure at this time is preferably 0.05 Pa or more and 8.00 Pa or less.

[0182] Next, a method for supplying plasma between the surface of the substrate 1 and the evaporation mechanism 24 by the plasma supply mechanism 50, i.e., plasma assistance during deposition, will be described. In this embodiment, plasma is generated within the cavity of the hollow cathode 51 of the plasma supply mechanism 50. Next, a discharge is generated between the hollow cathode 51 and the opposing anode, and the plasma within the cavity of the hollow cathode 51 is drawn between the surface of the substrate 1 and the evaporation mechanism 24.

[0183] In this embodiment, the discharge generated between the hollow cathode 51 and the opposing anode is an arc discharge, which means a discharge with a current value of 10 A or more, for example.

[0184] By evaporating aluminum while supplying plasma between the surface of the substrate 1 and the evaporation mechanism 24, the plasma is supplied to the aluminum vapor 63. The supply of plasma can promote the reaction or bonding of the aluminum vapor 63 with oxygen gas. This allows the aluminum vapor 63 to be oxidized before it reaches the surface of the substrate 1. The evaporated and oxidized aluminum adheres to the substrate 1, forming an aluminum oxide vapor deposition film on the surface of the substrate 1, and the barrier film shown in FIG. 1 can be produced.

[0185] The plasma raw material gas supplied by the plasma supply mechanism 50 is preferably argon gas.

[0186] In this embodiment, a plasma pretreatment step is performed before the film formation step, in which plasma is supplied to the surface of the substrate 1. In the plasma pretreatment step, an AC voltage is applied between the electrode unit 21 and the pretreatment roller 20. Furthermore, a magnetic field is generated in the space between the electrode unit 21 and the pretreatment roller 20 by utilizing the magnetic field generating unit 23 located on the surface of the electrode unit 21 opposite the surface facing the pretreatment roller 20. This allows plasma to be efficiently generated in the space between the electrode unit 21 and the pretreatment roller 20, and allows the plasma to be incident perpendicularly on the surface of the substrate 1 wrapped around the pretreatment roller 20. This therefore improves adhesion between the film formed in the film formation step and the substrate 1.

[0187] (Aging Treatment After Film Formation Step) The wound barrier film that has undergone the above-described film formation step is subjected to an aging treatment (heating treatment) for a predetermined period of time, which promotes the introduction of hydroxyl groups into the vapor-deposited aluminum oxide film, resulting in the formation of a vapor-deposited film with excellent oxygen permeability and water vapor permeability.

[0188] The aging temperature is preferably 50°C or higher and 60°C or lower. The lower limit of the aging time is 24 hours (1 day) or higher, more preferably 48 hours (2 days) or higher. The upper limit is 144 hours (6 days) or lower, more preferably 96 hours (4 days) or lower. The aging humidity is not particularly limited, but does not need to be high, and a normal relative humidity of 40% or higher and 70% or lower is sufficient.

[0189] (Coating Layer Formation Process) The coating layer 3 can be produced by the following method. First, a barrier coating agent is prepared by mixing the metal alkoxide, a water-soluble polymer, a silane coupling agent (if necessary), a sol-gel catalyst, an acid, and an organic solvent such as water or an alcohol (e.g., methyl alcohol, ethyl alcohol, isopropanol, etc.) as a solvent. Next, the barrier coating agent is applied to the aluminum oxide vapor-deposited film by a conventional method and dried. This drying process further promotes polycondensation of silanols generated from the metal alkoxide and silane coupling agent, forming a coating film. The drying conditions include a heat treatment at a temperature of 20 to 200°C and below the melting point of the plastic substrate, preferably in the range of 50 to 180°C, for 3 seconds to 10 minutes. This allows the coating layer 3 of the barrier coating agent to be formed on the aluminum oxide vapor-deposited film. The above coating operation may be further repeated on the first coating film to form multiple coating films consisting of two or more layers.

[0190] The barrier film roll that has undergone the coating layer formation step is then subjected to an aging treatment (heating treatment) for a predetermined period of time, which allows the condensation of the coating layer to proceed appropriately, resulting in a barrier film whose barrier properties are less likely to deteriorate after a retort test.

[0191] The lower limit of the aging temperature after the coating layer formation step is preferably 40°C or higher, more preferably 50°C or higher. The upper limit is preferably 100°C or lower, more preferably 70°C or lower. The lower limit of the aging time is 24 hours (1 day) or higher, more preferably 48 hours (2 days) or higher. The upper limit is 144 hours (6 days) or lower, more preferably 96 hours (4 days) or lower. The aging humidity is not particularly limited, but does not need to be high, and a normal relative humidity of 40% or higher and 70% or lower is sufficient.

[0192] (Film Forming Step 2) An aluminum oxide vapor deposition film may be further formed on the coating layer under the same conditions as those for the film forming step and aging treatment described above.

[0193] (Coating Layer Forming Step 2) A coating layer may be further formed on the aluminum oxide vapor-deposited film vapor-deposited through the film-forming step 2. The film can be formed under the same conditions as in the coating layer forming step described above.

[0194] (Laminate) FIG. 7 is a cross-sectional view showing an example of a laminate using a barrier film according to this embodiment. This laminate 100 is a laminate using the barrier film 100A of FIG. 1. That is, the barrier film 100A is composed of a first polypropylene substrate 110, an underlayer 115, a vapor-deposited film 120, and a coating layer 130 having barrier properties. One surface of the barrier film facing the first polypropylene substrate 110 is laminated to a sealant layer 150 via a first adhesive layer 161, and the other surface of the barrier film facing the coating layer 130 is laminated to a second polypropylene substrate 140 via an adhesive layer 162. That is, the laminate has a three-layer film configuration of second polypropylene substrate 140 / second adhesive layer 162 / barrier film / first adhesive layer 161 / sealant layer 150, with the barrier film serving as an intermediate layer. The configuration other than that of barrier film A will be described below.

[0195] [Adhesive Layer] The surface of the barrier film facing the first polypropylene substrate 110 is laminated to the sealant layer 150 via a first adhesive layer 161, and the surface of the barrier film facing the coating layer 130 is laminated to the second polypropylene substrate 140 via an adhesive layer 162. This improves the adhesion between the barrier film and the sealant layer, and between the first polypropylene substrate and the second substrate, and prevents the degradation of barrier properties during heat sterilization treatment such as retort or boiling.

[0196] The first adhesive layer 161 and the second adhesive layer 162 may be a one-component curing adhesive, a two-component curing adhesive, or a non-curing adhesive. The adhesive may be a solventless adhesive or a solvent-based adhesive suitable for dry lamination.

[0197] Examples of solvent-free adhesives, i.e., non-solvent lamination adhesives, include polyether adhesives, polyester adhesives, silicone adhesives, epoxy adhesives, and urethane adhesives. Among these, urethane adhesives are preferred, and two-component curing urethane adhesives are more preferred.

[0198] Examples of solvent-based adhesives include rubber-based adhesives, vinyl-based adhesives, olefin-based adhesives, silicone-based adhesives, epoxy-based adhesives, phenol-based adhesives, and urethane-based adhesives. Among these, urethane-based adhesives are preferred, and two-component curing urethane-based adhesives are more preferred.

[0199] The thickness of the adhesive layer is, for example, 0.1 μm or more and 10 μm or less, preferably 0.2 μm or more and 8 μm or less, and more preferably 0.5 μm or more and 6 μm or less.

[0200] [Second Polypropylene Base Material] The second polypropylene base material 140 is laminated to the surface of the barrier film facing the coating layer 30 via a second adhesive layer 162. Here, the second polypropylene base material may be the same as the first polypropylene base material 110, and therefore a description thereof will be omitted.

[0201] In the case of a three-layer structure as shown in Figure 7, the printed layer (not shown) may be formed on the surface of the outermost layer of the second polypropylene base material 140, or on the surface of the second polypropylene base material 140 on the second adhesive layer 162 side.

[0202] [Sealant Layer] The sealant layer 150 contains a resin material that can be fused to each other by heat. Examples of the resin material that can be fused to each other by heat include polyolefins, and specific examples include polyethylenes such as low-density polyethylene, linear low-density polyethylene, and medium-density polyethylene, polypropylene, polybutene, methylpentene polymers, and cyclic olefin copolymers.

[0203] The sealant layer is preferably made of polypropylene. This allows the three-layer film to be made entirely of polypropylene, making it possible to achieve a mono-material packaging material. After collecting used packaging materials, there is no need to separate the substrate and the sealant layer, improving the recyclability of the packaging material. By making the sealant layer of polypropylene, oil resistance can also be improved, and the sealant layer can be made to withstand heat sterilization treatment.

[0204] The polypropylene content in the sealant layer is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and still more preferably 95% by mass or more, which can improve the recyclability of the packaging material, for example.

[0205] When the sealant layer is made of polypropylene, the content of polypropylene relative to the total amount of resin materials contained in the laminate is preferably 80% by mass or more, more preferably 85% by mass or more, even more preferably 88% by mass or more, and particularly preferably 90% by mass or more. This allows, for example, the laminate to be used to produce a mono-material packaging material, thereby improving the recyclability of the packaging material.

[0206] Examples of polypropylene include propylene homopolymers, propylene random copolymers such as propylene-α-olefin random copolymers, and propylene block copolymers such as propylene-α-olefin block copolymers. Details of the α-olefins are as described above. From the viewpoint of heat sealability, the density of the polypropylene is, for example, 0.88 g / cm or more and 0.92 g / cm or less. The density is measured in accordance with JIS K7112, particularly Method D (density gradient tube method, 23°C). From the viewpoint of reducing the environmental load, biomass-derived polypropylene and / or recycled polypropylene may be used.

[0207] The sealant layer may contain additives. Examples of additives include crosslinkers, antioxidants, antiblocking agents, slip agents, UV absorbers, light stabilizers, fillers, reinforcing agents, lubricants, antistatic agents, pigments, and modifying resins. For example, the sealant layer may contain an antistatic agent. This can suppress the generation of static electricity on the surface of the laminate, thereby suppressing adhesion between laminates, for example.

[0208] The sealant layer may have a single-layer structure or a multi-layer structure. The thickness of the sealant layer is preferably 10 μm or more and 200 μm or less, more preferably 20 μm or more and 150 μm or less. When the thickness is equal to or more than the lower limit, for example, the lamination strength of a packaging material including the laminate can be further improved. When the thickness is equal to or less than the upper limit, for example, the processability of the laminate can be further improved. When a pouch (particularly a retort pouch) is produced from the laminate, the thickness of the sealant layer is more preferably 30 μm or more and 100 μm or less.

[0209] From the viewpoint of heat sealing properties, the sealant layer is preferably an unstretched resin film, more preferably an unstretched polypropylene film. The resin film can be produced by, for example, a casting method, a T-die method, or an inflation method. The sealant layer may be laminated via an adhesive layer as in the present embodiment, or may be formed by melt-extruding a resin material that can be fused to the barrier film by heat onto the barrier film.

[0210] 8 shows an example in which the coating layer 130 of the barrier film A is laminated to the sealant layer 150 via a first adhesive layer 161. As described above, in the present invention, the laminate is not limited to a three-layer film structure, and may also have a two-layer structure.

[0211] [Packaging Product] The above laminate can be used as a packaging product such as a packaging bag for containing contents such as food by forming the laminate into a bag shape with the sealant layer on the inside. The laminate of the present invention is a heat-sterilized laminate used for a packaging bag for containing retort foods or boiled foods.

[0212] The term "heat sterilization treatment" includes not only retort treatment but also boiling treatment, which refers to heat sterilization at 60 to 100°C for 10 to 60 minutes, for example.

[0213] Retort treatment refers to a heat-pressure sterilization treatment at 100 to 140°C. The F value, which is a concept representing the integrated value of the heat load, is 4 or more, more specifically, a heat-pressure sterilization treatment at 121°C for 3 minutes or more, or a heat-pressure sterilization treatment at 120°C for 4 minutes or more as defined by the Food Sanitation Act is preferred. More specifically, 120°C for 30 to 60 minutes is most common, but semi-retort at 105 to 115°C for 30 to 60 minutes or high-retort (HTST) at 130 to 140°C for 30 to 60 minutes may also be used.

[0214] [Composite Elastic Modulus and Indentation Hardness of Coating Layer] In the present invention, the composite elastic modulus and indentation hardness after lamination and the above-mentioned heat sterilization treatment are measured by nanoindentation from a cross section of the coating layer of the laminate, and are 5.0 GPa to 8.5 GPa, and the indentation hardness is 0.9 GPa to 1.7 GPa. Within these ranges, degradation of the barrier property of the laminate can be suppressed not only after boiling treatment but also after retort treatment.

[0215] It is more preferable that the composite elastic modulus is 6.0 GPa or more and 8.5 GPa or less and the indentation hardness is 1.0 GPa or more and 1.5 GPa or less, and this can prevent the degradation of the barrier properties even after high-temperature retort treatment of the laminate.

[0216] The indentation hardness of the coating layer is calculated by the following formula (1): Furthermore, the composite elastic modulus of the coating layer is calculated by the following formula (2): Indentation hardness = Pmax / A (1)

[0217] Where, Pmax: Maximum load (unit: μN) A: Contact projection area at maximum depth (unit: μm ２ ) S: Contact stiffness.

[0218] The composite modulus and indentation hardness of the coating layer of the heat-sterilized laminate were measured by embedding the heat-sterilized laminate in epoxy resin or the like and processing it with a microtome to expose the cross-section of the coating layer. This allows measurements to be made from the "cross-section" of the coating layer of the laminate using the nanoindentation method. This method allows the composite modulus and indentation hardness of the coating layer to be measured without peeling the laminate to expose the coating layer. The cross-section was obtained by cutting the film in the thickness direction perpendicular to the main surface. The cross-section was prepared by embedding the film in an embedding resin to create a block, and then cutting the block using a commercially available rotary microtome at room temperature (23°C). Finishing was performed with a diamond knife.

[0219] To measure the indentation hardness and composite modulus of the cross section of the coating layer using the nanoindentation method, first, an indenter is placed on the cross section of the coating layer, and the indenter is pressed down from the cross section to a load of 15 μN over 10 seconds, and held in that state for 5 seconds. The indenter is pressed near the center of the exposed cross section of the coating layer in the thickness direction. The load is then released over 10 seconds. This provides the maximum load Pmax, the contact projected area A at maximum depth, and the load-displacement curve. Unless otherwise specified, measurements are performed in an environment of 50% relative humidity and 23°C. Measurements are performed at five or more locations on the same cross section, and the indentation hardness and composite modulus are reported as the arithmetic mean of the values ​​measured at five locations with good reproducibility. Further detailed measurement conditions are described in the Examples.

[0220] When the laminate is subjected to heat sterilization, the coating layer needs to have a certain degree of hardness to prevent destruction of the vapor-deposited film due to thermal shrinkage of the OPP substrate during heat sterilization. On the other hand, during lamination processing of the packaging material, the OPP substrate is stretched by tension, which also causes destruction of the vapor-deposited film, resulting in a decrease in barrier properties. However, this decrease in barrier properties can be prevented by imparting appropriate flexibility to the coating layer.

[0221] The inventors have discovered a range of elastic modulus and indentation hardness suitable for heat sterilization treatment applications such as retort treatment for the coating layer that constitutes a monomaterial packaging material, which is a laminate of polypropylene films, and have found a laminate that can suppress a decrease in barrier properties even after "heat sterilization treatment" of "lamination."

[0222] As a result, the oxygen permeability of the laminate after heat sterilization treatment at 23°C and 90% RH according to JIS K 7126-2 was 10.0 cc / (m ２ ·day·atm) or less, preferably 5.0 cc / (m ２ ·day·atm) or less, particularly preferably 2.0 cc / (m ２ ·day·atm) or less, most preferably 1.0 cc / (m ２ ·day·atm) or less. In addition, the water vapor transmission rate at 40°C and 100% RH according to JIS K 7129 B method after heat sterilization is preferably 2.0 g / (m ２ ·day), more preferably less than 1.5 g / (m ２ ·day) or less, particularly preferably 1.0 g / (m ２ In this way, a laminate having high gas barrier properties can be obtained even after retort treatment.

[0223] The composite elastic modulus and indentation hardness of the coating layer can be adjusted, for example, by changing the composition of the coating layer or the drying temperature during coating layer formation.

[0224] The present invention will be described in further detail below with reference to examples, but the present invention is not limited to these descriptions in any way. First, barrier films according to Examples 1 to 13 and Comparative Examples 1 to 10 were produced using the film formation apparatus 10, which is the film formation apparatus described in this embodiment, and the film formation method and coating layer formation process. Pretreatment conditions, deposition conditions, etc. are summarized in Tables 1 and 2.

[0225] (Example 1) A 20 μm-thick biaxially oriented polypropylene film was used as the polypropylene base material for the substrate 1 (the first layer, which is the surface on the vapor deposition side, is a 1.0 μm-thick layer made of a copolymer of propylene, ethylene, and butene; the second layer, which is the surface opposite to the vapor deposition side, is a 1.0 μm-thick layer made of a copolymer of propylene, ethylene, and butene; the surface of the first layer was corona-treated; and the third layer (intermediate layer) was a 18 μm-thick homopolypropylene).

[0226] Next, a coating liquid for forming an anchor coat layer, which was a mixture of a hydroxyl group-containing (meth)acrylic resin and tolylene diisocyanate, was applied onto the first layer of the substrate 1 by a direct gravure method as a base layer, and then dried to form an anchor coat layer having a thickness of 0.2 μm.

[0227] After forming the anchor coat layer, the roll material was rewound in an atmosphere of 25° C. and 50% RH as a humidity conditioning step, and then stored at 25° C. and 50% RH for 3 days to condition the humidity.

[0228] In the film formation process, a vapor deposition film containing aluminum oxide was formed by vacuum deposition using a resistance heating type (represented as RH in Table 1) evaporation mechanism 24 as shown in Fig. 6. Specifically, while aluminum metal wires were supplied into a boat 24b as a vapor deposition material, the vapor deposition material in the boat 24b was heated using the resistance heating type evaporation mechanism 24, and the aluminum was evaporated so as to reach the surface of the substrate 1. At the same time, a vapor deposition film was formed on the surface of the substrate 1 while oxygen was supplied.

[0229] 6 and anodes (not shown) disposed on both sides of the substrate 1 in the width direction as viewed from the boat 24b, facing the opening of the hollow cathode 51. A plasma source gas (argon gas) was supplied to the hollow cathode 51, and a discharge was generated to excite plasma. This plasma was then extracted by the opposing anode between the surface of the substrate 1 and the evaporation mechanism 24, thereby performing plasma assist during deposition. The plasma assist conditions were as follows: argon gas supply rate to the hollow cathode: 80 sccm, anode current: 154 A, and anode voltage: 18 V. Note that no plasma post-treatment process was performed after the plasma assist process during deposition.

[0230] A vapor-deposited film was laminated on the substrate 1 by the above method. The conveying speed was 600 m / min, and the thickness of the vapor-deposited film was 8.9 nm. The light transmittance at a wavelength of 366 nm measured in-line after vapor deposition was set to 100% based on the transmittance of the substrate 1 in a pre-treated state without vapor deposition. Vapor deposition was then started, and the oxygen supply rate was feedback-controlled to achieve a light transmittance of 99.7%. The pressure during vapor deposition was 1.1 Pa.

[0231] The barrier film roll that had undergone the above-described film-forming process was subjected to an aging treatment at 55° C. and 50% RH for 3 days.

[0232] Furthermore, a coating layer was laminated on the vapor-deposited film in a coating layer forming process. Polyvinyl alcohol with a saponification degree of 99% or more and a degree of polymerization of 2400 was mixed as a water-soluble polymer with a liquid of water and isopropyl alcohol in a ratio of 95 / 5 to obtain solution A adjusted to a solid content of 4%. Water, isopropyl alcohol, and 1N hydrochloric acid were mixed in a ratio of 65 / 34 / 1 to obtain solution B. Tetraethoxysilane was used as a metal alkoxide to prepare solution C. A liquid obtained by adjusting the ratio of solution B and solution C and mixing it was used as solution D, and a liquid obtained by adjusting the ratio of solution A and solution D and mixing it was used as a barrier coating agent. The barrier coating agent had a solid content of 7% after mixing, with the SiO of tetraethoxysilane being 100% of the solid content of PVA. ２The ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 2.5. This barrier coating agent was designated as solution X.

[0233] The barrier coating agent prepared above was applied onto the vapor-deposited film using an applicator. The film was then dried at 100°C to form a coating layer with a dry thickness of 300 nm. This was followed by aging treatment at 55°C and 50% RH for 7 days to form a coating layer, thereby producing the barrier film of Example 1.

[0234] Example 2 A barrier film of Example 2 was produced in the same manner as in Example 1, except that the plasma assist conditions in the film formation step were an anode current of 140 A and an anode voltage of 16 V.

[0235] Example 3 A barrier film of Example 3 was produced in the same manner as in Example 2, except that the aging treatment after the film formation step was carried out at 60° C. and 50% RH for 4 days.

[0236] (Example 4) In the coating layer forming process, the SiO of tetraethoxysilane was ２ The barrier film of Example 4 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 2.25.

[0237] (Example 5) In the coating layer forming process, the SiO of tetraethoxysilane was ２ A barrier film of Example 5 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 2.75.

[0238] (Example 6) In the coating layer forming process, the SiO of tetraethoxysilane was ２ The barrier film of Example 6 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 3.0.

[0239] (Example 7) In the coating layer forming process, the SiO of tetraethoxysilane was ２The barrier film of Example 7 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 3.5.

[0240] Example 8 A barrier film of Example 8 was produced in the same manner as in Example 1, except that solution Y was used in the coating layer formation step. When mixing solutions B and C, 5% of glycidoxypropyltrimethoxysilane was added relative to the weight of tetraethoxysilane, and then a coating layer was formed with a solid content of 7% and SiO of tetraethoxysilane relative to the solid content of PVA. ２ The ratio of solutions B and C and the ratio of solutions A and D were adjusted so that the converted mass was 2.5, and the resulting mixture was designated solution Y as a barrier coating agent.

[0241] (Example 9) In the coating layer forming process, the SiO of tetraethoxysilane was ２ The barrier film of Example 9 was produced in the same manner as in Example 8, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 3.5.

[0242] Example 10 A barrier film of Example 10 was produced in the same manner as in Example 1, except that Solution Z was used in the coating layer formation step. When mixing Solutions B and C, 8% of 1,3,5-tris(3-trialkoxysilylpropyl)isocyanurate was added relative to the weight of tetraethoxysilane, and a coating layer was produced with a solid content of 7%, and the SiO content of tetraethoxysilane relative to the solid content of PVA was 1.0%. ２ The ratio of solutions B and C and the ratio of solutions A and D were adjusted so that the converted mass was 3.5, and the resulting mixture was designated solution Z as a barrier coating agent.

[0243] Example 11 A barrier film of Example 11 was produced in the same manner as in Example 1, except that the aging treatment after the formation of the coating layer was not carried out.

[0244] Example 12 A barrier film of Example 12 was produced in the same manner as in Example 7, except that the aging treatment after the formation of the coating layer was not carried out.

[0245] (Example 13) As the substrate 1, a substrate (total thickness 20 μm) was used, which was multilayer coextruded and then stretched, with a polyamide resin as the underlayer, a modified polypropylene as the first layer, a homopolypropylene as the third layer, and a layer made of a propylene-ethylene copolymer as the second layer, in the order of underlayer / first layer / third layer / second layer. The underlayer had a thickness of 0.6 μm, the first layer had a thickness of 1.5 μm, and the second layer had a thickness of approximately 0.6 μm. Nylon 6 was used as the polyamide resin.

[0246] Thereafter, in a humidity conditioning step, the roll material was rewound in an atmosphere of 25° C. and 50% RH, and then stored at 25° C. and 50% RH for 3 days to condition the humidity.

[0247] A gas barrier film of Example 13 was produced by carrying out the film formation process and the coating layer formation process in the same manner as in Example 1, except that the following pretreatment process was carried out in the film formation process of Example 1. <Pretreatment Process> Plasma pretreatment was carried out on the surface of the substrate 1 using the plasma pretreatment mechanism 11B shown in Figures 2 and 3. Specifically, first, a plasma-forming gas was supplied to the plasma pretreatment chamber 12B using the plasma raw material gas supply unit, while the air pressure inside the plasma pretreatment chamber 12B was adjusted using the decompression chamber 12. Next, a voltage was applied between the pretreatment roller 20 and the electrode unit 21 to generate plasma, and the surface of the substrate 1 was subjected to plasma pretreatment. The plasma pretreatment was carried out under the following conditions. <Pretreatment Conditions> Substrate conveying speed: 600 m / min High-frequency power output: 4 kW High-frequency power frequency: 40 kHz Plasma intensity: 550 W·sec / m ２ Plasma forming gas: oxygen 100 (sccm), argon 1000 (sccm) Magnetic forming means: 1000 gauss permanent magnet Voltage applied between pretreatment drum and plasma supply nozzle: 420 V Pressure in pretreatment section: 2.0 x 10 －１ Pa

[0248] (Example 14) As the substrate 1, a mixture of 50% by mass of a copolymer of meta-xylenediamine and adipic acid and 50% by mass of a copolymer of a dicarboxylic acid having a molar ratio of isophthalic acid / terephthalic acid of 2 / 1 and hexamethylenediamine (referred to as PA mixture in Table 1), an acid-modified polypropylene random copolymer as the first layer, homopolypropylene as the third layer, and a layer of a copolymer of propylene, ethylene, and butene as the second layer was co-extruded as a base layer / first layer / third layer / second layer, and then, using a sequential biaxial stretching device, the film was stretched 5 times in the longitudinal direction (MD direction) and 10 times in the transverse direction (TD direction) to produce a base film having a thickness of 20 μm, comprising a base layer (0.7 μm), a first layer (1.5 μm), a third layer (17.1 μm), and a second layer (0.7 μm).

[0249] Thereafter, in a humidity conditioning step, the roll material was rewound in an atmosphere of 25° C. and 50% RH, and then stored at 25° C. and 50% RH for 3 days to condition the humidity.

[0250] The film formation process of Example 3 was carried out in the same manner as in Example 1, except that the aging treatment after the film formation process was carried out at 55° C. and 50% RH for 7 days.

[0251] The gas barrier film of Example 14 was produced without carrying out the subsequent coating layer forming step.

[0252] Example 15 After the film-forming process for the gas barrier film of Example 14, a coating liquid for forming a coating layer (shown as PU in Table 2), which was a mixture of a polyurethane emulsion and an emulsion of an oxazoline group-containing polymer, was applied by a direct gravure method and then dried to form a coating layer with a thickness of 200 nm. This was then subjected to an aging treatment at 55°C and 50% RH for 7 days, thereby producing the barrier film of Example 15.

[0253] Comparative Example 1 A barrier film of Comparative Example 1 was produced in the same manner as in Example 1, except that in the film-forming step, the plasma-assisted conditions were an anode current of 176 A and an anode voltage of 18 V.

[0254] Comparative Example 2 A barrier film of Comparative Example 2 was produced in the same manner as in Example 1, except that the aging treatment after the film formation step was not carried out.

[0255] Comparative Example 3 A barrier film of Comparative Example 3 was produced in the same manner as in Example 1, except that in the film-forming step, the plasma-assisted conditions were an anode current of 48 A and an anode voltage of 19 V.

[0256] Comparative Example 4 A barrier film of Comparative Example 4 was produced in the same manner as in Example 1, except that plasma assistance was not performed in the film-forming step.

[0257] Comparative Example 5 A barrier film of Comparative Example 5 was produced in the same manner as in Example 1, except that in the film formation step, the conveying speed was 670 m / min, the thickness of the vapor-deposited film was 8.0 nm, the light transmittance was 94.0%, the pressure was 0.3 Pa, and plasma assistance was not performed.

[0258] Comparative Example 6 A barrier film of Comparative Example 6 was produced in the same manner as in Example 1, except that the light transmittance was 88.0% and the pressure was 0.2 Pa in the film-forming step.

[0259] (Comparative Example 7) In the coating layer forming step, the SiO of tetraethoxysilane was ２ A barrier film of Comparative Example 7 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 1.5.

[0260] (Comparative Example 8) In the coating layer forming step, the SiO of tetraethoxysilane was ２ A barrier film of Comparative Example 8 was produced in the same manner as in Example 1, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 4.0.

[0261] (Comparative Example 9) In the coating layer forming step, the SiO content of tetraethoxysilane was ２ A barrier film of Comparative Example 9 was produced in the same manner as in Example 10, except that the ratio of solution B to solution C and the ratio of solution A to solution D were adjusted so that the converted mass was 4.0.

[0262] (Comparative Example 10) A barrier film of Comparative Example 10 was produced in the same manner as in Comparative Example 5, except that the substrate having the undercoat layer of Example 13 was used as the substrate 1 and the same pretreatment step as in Example 13 was carried out in the film formation step.

[0263]

[0264]

[0265] [Acquisition and analysis of XAFS spectra] For the barrier films of Examples 1 to 4 and Comparative Examples 1 to 10, XAFS spectra were obtained from the surface side of the barrier film (from the surface side of the vapor-deposited film or the surface side of the coating layer) under the measurement conditions below. Of these, the results for Example 1 are shown in Figure 9. In the figure, the vertical axis represents the intensity of the emitted fluorescent X-rays (shown as absorption intensity (a.u) in the figure), and the horizontal axis represents the light (or X-ray) energy (eV).

[0266] <XAFS spectrum acquisition> ・Line used: Aichi Synchrotron Light Center BL1N2 ・Acceleration energy: 1.2 GeV ・Beam size: 1.0 mm horizontal x 1.0 mm vertical ・Angle of incidence to sample: 22.5° (the direction perpendicular to the sample is 0°) ・Entrance slit: 30 μm ・Exit slit: 30 μm ・Measurement method: Partial fluorescence yield method ・Energy range (Al K-edge): 1500-1700 eV ・Energy step: 1500-1550 eV: 2.0 eV / step 1550-1555 eV: 1.0 eV / step 1555-1575 eV: 0.2 eV / step 1575-1600 eV: 0.5 eV / step 1600 to 1680 eV: 1.0 eV / step 1680 to 1700 eV: 2.0 eV / step (Storage time: all 10 s / point) Energy calibration: Energy calibration using Au 4f 7 / 2 on an Au plate (calibrated using the value obtained by subtracting the theoretical value of 1500 eV from the actual measured value)

[0267] <XAFS Spectrum Analysis> Peak Separation Method Intensity values ​​were normalized so that the absorption spectrum intensity value at an absorption X-ray energy value of 1557 eV was 0 and the absorption spectrum intensity value at an absorption X-ray energy value of 1590 eV was 1.

[0268]

[0269] The normalized data points from 1555 eV to 1575 eV and from 1598 eV to 1602 eV were extracted, and the above f(x) function was fitted to determine each coefficient. １ = k ２ , K. １ =X １ , K. ２ =X ２ The constraints are included. Fitting was performed using the least squares method. In this case, the least squares function in the Python scipy library was used, and the initial values ​​of the coefficients were calculated by giving the values ​​shown in the table below. The symbols for the above functions are defined as follows: M ｉ : Weighting factor of Gaussian function and Lorentzian function at the i-th absorption peak X ｉ : Peak center of the i-th absorption peak h ｉ : Peak intensity factor β of the i-th absorption peak ｉ : Peak width factor k of the i-th absorption peak ｊ : baseline intensity factor K in the jth baseline ｊ : Half-division position of the baseline intensity in the jth baseline

[0270]

[0271] The results of peak separation of the XAFS spectrum of Example 1 are shown in Fig. 10. Similarly, Fig. 11 shows the analysis results of the XAFS peaks of Example 2, Fig. 12 shows the analysis results of the XAFS peaks of Comparative Example 4, and Fig. 13 shows the analysis results of the XAFS peaks of Comparative Example 5.

[0272] "Experiment" is the measured XAFS spectrum, "Fit. Peak 1" is the isolated intensity peak near 1566 eV, "Fit. Peak 2" is the isolated intensity peak near 1568 eV, and "Fit. Peak 3" is the isolated intensity peak near 1572 eV. From this, the XAFS peak top ratio P = (intensity peak top near 1572 eV) / (intensity peak top near 1566 eV) was calculated, and the results are shown in Table 4 for the barrier films of Examples 1 to 13 and Comparative Examples 1 to 10.

[0273] [Elemental Analysis of Coating Layer] The narrow spectrum of each element was measured for the coating layer surface of the barrier films of Examples 1 to 13 and Comparative Examples 1 to 10 using an X-ray photoelectron spectroscopy analyzer (XPS). The surface after measurement was then etched under the conditions described below to expose a new measurement surface. Narrow spectra of each element were measured for the exposed measurement surface under the same conditions. For each narrow spectrum of C1s and Si2p, analysis software was used to subtract the background using the Shirley method to obtain the integrated intensity (area) of the peak for each element. The obtained integrated intensity (area) was used to calculate the proportion of each element (element %). The Si / C ratio was calculated from the proportion of each element after two 60-second etchings, and is shown in Table 4. <X-ray photoelectron spectrum measurement conditions> Apparatus: ESCA3400 manufactured by Shimadzu Corporation X-ray source: MgKα Emission current: 20 mA Acceleration voltage: 10 kV Resolution: Low Measurement area: Approximately 6 mmφ <Etching conditions> Ion species: Ar ＋ Ar gas introduction pressure: 2.0 × 10 －２ Pa Emission current: 30 mA Acceleration voltage: 0.3 kV Etching time: 60 seconds x 2 times

[0274]

[0275] <Preparation of Laminate> For each of the barrier films of Examples 1 to 13 and Comparative Examples 1 to 10, the surface of the barrier film facing the coating layer 130 was bonded to a second biaxially oriented polypropylene film 140 (thickness: 20 μm) by dry lamination using a polyurethane-based two-component curing solvent-based adhesive, with the second adhesive layer 162 interposed therebetween. Furthermore, the surface of the barrier film opposite the coating layer 130 was bonded to a sealant layer (unstretched polypropylene film, 60 μm) by dry lamination using a two-component curing solvent-based adhesive, with the first adhesive layer 161 interposed therebetween, to produce the laminate of Example 1.

[0276] <Retort Treatment> The laminates of Examples 1 to 13 and Comparative Examples 1 to 10 were subjected to a retort treatment at 121°C for 30 minutes and a high retort treatment at 135°C for 30 minutes.

[0277] <Measurement of Barrier Properties of Barrier Films and Laminates> The water vapor permeability and oxygen permeability were measured for the barrier films and laminates using them of Examples 1 to 13 and Comparative Examples 1 to 10. The results are shown in Tables 5 and 6.

[0278] Oxygen permeability (cc / (m ２ The oxygen permeability (OTR) was measured in accordance with JIS K 7126-2 using an oxygen transmission rate measuring device (manufactured by Mocon Co., Ltd., product name "OX-TRAN 2 / 20") under the measurement conditions of 23°C and 90% RH.

[0279] Water vapor permeability (g / (m ２ The water vapor transmission rate (day, indicated as "WVTR" in the table) was measured in accordance with JIS K 7129 B method under the measurement conditions of 40°C and 100% RH using a water vapor transmission rate measuring device (manufactured by Mocon, product name "PERMATORAN-W 3 / 31").

[0280] <Measurement of composite elastic modulus and indentation hardness of coating layer> For the laminates of Examples 1 to 13 and Comparative Examples 1 to 10, the composite elastic modulus (GPa) and indentation hardness (GPa) of the coating layer of the laminates after heat sterilization treatment were measured under the following conditions. The results are shown in Tables 5 and 6. Measuring device: HYSITRON TI-950 Triboindenter Measurement location: From the cross-section side of the coating layer Measurement mode: Indentation Indenter: Cubecorner indenter, TI-0037 Number of data points: 200 points / second Measurement profile 0 → 10 sec: 0 → 15 μN 10 → 15 sec: 15 μN 15 → 25 sec: 15 → 0 μN

[0281]

[0282]

[0283] From Tables 5 and 6, it can be seen that the laminates using the barrier films using the polypropylene base materials according to the present embodiment, in which the peak top ratio P obtained from the XAFS spectrum is 0.70 or more and less than 1.05, have high barrier properties after retort treatment.

[0284] Furthermore, it can be seen that a laminate using a polypropylene base material having a composite elastic modulus of 5.0 GPa or more and 8.5 GPa or less and an indentation hardness of 0.9 GPa or more and 1.7 GPa or less has excellent oxygen barrier properties after retort treatment.

[0285] DESCRIPTION OF SYMBOLS 110 (First) polypropylene substrate 115 Undercoat layer 120 Vapor-deposited film 130 Coating layer 140 Second polypropylene substrate 150 Sealant layer 161 First adhesive layer 162 Second adhesive layer 100, 200 Laminate 100A Barrier film 10 Film-forming device P Plasma X Rotating shaft 11A Substrate transport mechanism 11B Plasma pretreatment mechanism 11C Film-forming mechanism 12 Decompression chamber 12A Substrate transport chamber 12B Plasma pretreatment chamber 12C Film-forming chamber 13 Unwinding roller 14a-d Guide roll 15 Winding roller 20 Pretreatment roller 21 Electrode section 23 Magnetic field forming section 23a First surface 23b Second surface 231 First magnet 231c First axial portion 232 Second magnet 232c Second axial portion 232d Connection portion 24 Evaporation mechanism 24b Boat 25 Film-forming roller 31 Power supply wiring 32 Power source 35a to 35c Partition wall 50 Plasma supply mechanism 51 Hollow cathode 61 Evaporation material supply unit 63 Aluminum vapor

Claims

1. A barrier film comprising a polypropylene substrate, an undercoat layer, and an aluminum oxide vapor-deposited film laminated in this order, wherein the aluminum oxide vapor-deposited film has a peak top ratio P of 0.70 or more and less than 1.05 when X-ray absorption fine structure analysis is performed on the surface side of the barrier film opposite to the polypropylene substrate, as defined below: P = (intensity peak top near 1572 eV) / (intensity peak top near 1566 eV).

2. The barrier film according to claim 1, wherein a coating layer having barrier properties is laminated on the aluminum oxide vapor deposition film.

3. The barrier film according to claim 2, wherein the coating layer has a ratio of silicon atoms to carbon atoms (Si / C) of 1.30 or more and 1.65 or less as measured by X-ray photoelectron spectroscopy (XPS).

4. The barrier film according to claim 1, wherein the undercoat layer is an anchor coat layer formed on the polypropylene substrate.

5. The barrier film according to claim 1, wherein the undercoat layer is a surface resin layer containing a polyamide resin formed on the polypropylene substrate.

6. A barrier film according to claim 4, wherein the polypropylene base material has at least a first layer and a second layer as two surface layers, the first layer being formed on the underlayer side, the first layer containing a copolymer of propylene and another monomer, the underlayer being the anchor coat layer, and the first layer of the polypropylene base material, the anchor coat layer, the aluminum oxide vapor deposition film, and the coating layer having barrier properties are laminated in this order.

7. A barrier film according to claim 5, wherein the polypropylene base material has at least a first layer and a second layer as two surface layers, the first layer being formed on the side of the undercoat layer, the first layer containing modified polypropylene, the undercoat layer being the surface resin layer containing the polyamide resin, and the first layer of the polypropylene base material, the surface resin layer containing the polyamide resin, the aluminum oxide vapor deposition film, and the coating layer having barrier properties are laminated in this order.

8. A barrier film according to claim 1, wherein the polypropylene base material has at least a first layer and a second layer as two surface layers, the second layer being formed on the surface opposite to the undercoat layer, the second layer containing a copolymer of propylene and another monomer, and the first layer of the polypropylene base material, the undercoat layer, the aluminum oxide vapor-deposited film, and the coating layer having barrier properties are laminated in this order.

9. A heat-sterilized laminate comprising a barrier film according to any one of claims 1 to 8 and a sealant layer, for use in a packaging bag for containing retort food or boiled food, wherein the composite modulus and indentation hardness of the coating layer of the laminate, as measured by nanoindentation method from a cross section of the coating layer, are 5.0 GPa or more and 8.5 GPa or less, and the indentation hardness is 0.9 GPa or more and 1.7 GPa or less.

10. A packaging product comprising the laminate of claim 9.

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