Gas barrier film, gas barrier film with transparent conductive layer laminated thereon, and perovskite solar cell using same

Abstract

Provided is an excellent gas barrier film that has high barrier properties, and, when used as a constituent member of electronic devices requiring high gas barrier properties, such as a solar cell and an electroluminescent display device, can maintain stable performance of the electronic device for a long period of time.　The gas barrier film is obtained by laminating a zinc oxide-based composite oxide film on at least one surface of a transparent plastic film substrate. The average value of the arithmetic average height SRa of the zinc oxide-based composite oxide film is 0.01-3 nm. The foreign matter density of the zinc oxide-based composite oxide film as determined by the embedded foreign matter evaluation is 0.40 pieces / mm2 or less. The outgas amount of the gas barrier film is 100 ppm or less.

Description

Gas barrier film with laminated gas barrier film and transparent conductive layer, and perovskite solar cell using the same.

[0001] The present invention relates to a gas barrier film having a gas barrier film and a transparent conductive layer laminated on top of it, and more particularly to a perovskite solar cell using these.

[0002] Barrier films that block oxygen and water vapor are widely used not only in food packaging but also as industrial components due to their lightness and flexibility. Conventionally, barrier films are widely known to be made by depositing silicon oxide-based or aluminum oxide-based thin films onto a film substrate by vapor deposition (see, for example, Patent Documents 1 and 2). However, these deposited films have the problem of insufficient barrier properties in fields requiring high gas barrier properties, such as display applications and solar cells. In order to achieve higher barrier properties than these silicon oxide-based and aluminum oxide-based films, it has been proposed to use a composite oxide of zinc oxide and silicon oxide as the barrier layer (see, for example, Patent Document 3). However, such conventional technologies have not been sufficient to maintain stable performance over long periods. In particular, in next-generation devices that are extremely sensitive to moisture and impurities, such as perovskite solar cells, not only the composition of the barrier layer but also microscopic control of the film surface and suppression of outgassing are essential, but conventional technologies have not been able to adequately achieve both.

[0003] Japanese Patent Publication No. 2015-196315, Japanese Patent Publication No. 2014-073598, Japanese Patent Publication No. 2018-138381

[0004] This invention was made against the backdrop of the problems of the prior art. Specifically, the object of this invention is to provide a gas barrier film that has high barrier properties and, when used as a component of electronic devices that require high gas barrier properties, such as solar cells and electroluminescent display devices, can maintain stable performance as an electronic device for a long period of time. In addition, by laminating a transparent conductive layer onto the gas barrier film, it is possible to give the gas barrier film the function of a transparent conductive film in an electronic device, thereby enabling further thinning of the device and providing a gas barrier film that is advantageous in terms of cost, productivity, and resource conservation. Furthermore, the invention aims to provide thin electronic devices, particularly perovskite solar cells, using these gas barrier films.

[0005] The inventors diligently studied to achieve the above objective and have completed the present invention. That is, the present invention is as follows: (1) A gas barrier film in which a zinc oxide-based composite oxide film is laminated on at least one surface of a transparent plastic film substrate, wherein the average value of the arithmetic mean height SRa of the zinc oxide-based composite oxide film is 0.01 to 3 nm, and the foreign matter density of the zinc oxide-based composite oxide film, as determined by the following embedded foreign matter evaluation, is 0.40 particles / mm ２A gas barrier film wherein the outgassing amount of the gas barrier film is 100 ppm or less. (2) The gas barrier film according to (1), wherein the zinc oxide-based composite oxide film comprises 45 to 97 atomic percent zinc oxide, 2.5 to 50 atomic percent silicon oxide, and 0.05 to 10 atomic percent aluminum oxide. (3) The gas barrier film according to (1), wherein the zinc oxide-based composite oxide film comprises 30 to 97 atomic percent zinc oxide, 2.5 to 50 atomic percent silicon oxide, and 0.05 to 35 atomic percent metal oxide A, and the metal oxide A is an oxide containing one or more elements from among B, Ga, In, Tl, Sc, and Y. (4) The gas barrier film according to any one of (1) to (3), wherein the thickness of the zinc oxide-based composite oxide film is 15 to 70 nm. (5) The gas barrier film according to any one of (1) to (4), wherein a transparent conductive layer is laminated on at least one surface of the gas barrier film on which the zinc oxide-based composite oxide film is laminated. (6) A gas barrier film according to any one of (1) to (5), wherein the color difference b is 2.0 or less and the total light transmittance in the absence of a transparent conductive layer is 86% or more. (7) A gas barrier film according to any one of (1) to (6), wherein a transparent conductive layer is laminated on at least one surface of the gas barrier film on which the zinc oxide-based composite oxide film is laminated, the color difference b is 2.0 or less, and the total light transmittance is 80% or more. (8) A gas barrier film according to any one of (1) to (7), wherein the arithmetic mean height SRa on the opposite side of the zinc oxide-based composite oxide film is 5 nm or less. (9) A gas barrier film according to any one of (1) to (8), wherein the maximum peak height SRp on the opposite side of the zinc oxide-based composite oxide film is 150 nm or less. (10) A gas barrier film according to any one of (1) to (9), wherein the average maximum peak height SRp of the zinc oxide-based composite oxide film is 50 nm or less. (11) A perovskite solar cell comprising a gas barrier film as described in any of (1) to (10). (12) A perovskite solar cell comprising a structure in which a hole transport layer, a perovskite layer, an electron transport layer, an electrode layer, and a substrate are stacked in that order on a transparent conductive layer of the gas barrier film as described in any of (1) to (10).(13) A perovskite solar cell comprising a structure in which an electron transport layer, a perovskite layer, a hole transport layer, an electrode layer, and a substrate are stacked in that order on a transparent conductive layer of a gas barrier film as described in any of (1) to (10).

[0006] The present invention provides a gas barrier film with low outgassing and excellent smoothness, enabling it to maintain stable performance over long periods when used as a component in electronic devices requiring high gas barrier properties, such as solar cells and electroluminescent display devices. In one embodiment, a configuration with a laminated transparent conductive layer contributes to device thinning, process simplification, and cost reduction.

[0007] Schematic diagram of a perovskite solar cell cross-section. Schematic diagram of a sputtering apparatus. Explanatory diagram of a helium gas transmission rate measurement method. Explanatory diagram of a method for measuring the height difference of irregularities on the end face of a film roll.

[0008] The gas barrier film of the present invention has a zinc oxide-based composite oxide film laminated as a gas barrier layer on at least one surface of a transparent plastic film substrate. The details will be described below. In the following, the zinc oxide-based composite oxide film may simply be referred to as the composite oxide film.

[0009] [Gas Barrier Layer] In the present invention, it is preferable that the gas barrier layer be a zinc oxide-based composite oxide film. Preferred composite components other than zinc oxide include oxides of silicon (Si), aluminum (Al), gallium (Ga), titanium (Ti), zirconium (Zr), tin (Sn), indium (In), niobium (Nb), molybdenum (Mo), tantalum (Ta), chromium (Cr), and copper (Cu). By including the composite component, the crystal growth of zinc oxide is suppressed, the flexibility of the gas barrier layer is improved, crack formation in the film is suppressed, and a barrier film with high barrier properties and ease of handling is obtained. Note that when a component is expressed by element symbol below, it includes an oxide, and as an example of an oxide, Si is SiO ２ Not only that, but also those that are not completely oxidized, for example, SiO ｘThis also includes (x = 1 to 2), etc. Similarly, AlOx (x = 1 to 1.5), etc. The same applies to Ga, Ga ２ O ３ This includes not only those that are not completely oxidized, but also those that are not completely oxidized, such as GaOx (x = 0.5 to 1.5). Furthermore, the metal oxide A described later also includes those that are not completely oxidized, not just the corresponding stable oxide.

[0010] Among these, it is more preferable to include Si, Al, or Ga as a composite component, and even more preferable to include Si. From the viewpoint of achieving both high gas barrier properties and long-term stability, it is even more preferable to include both Si and Al, or both Si and Ga. In one embodiment, it is preferable to use a composite oxide of three components: zinc, silicon, and aluminum, and it may also be a composite oxide of three components: zinc, silicon, and gallium. The amorphous nature of the film is increased and the film quality is densified, which can contribute to suppressing the crystallization and corrosion of zinc oxide under high temperature and high humidity conditions. In another embodiment, the zinc oxide-based composite oxide film may include metal oxide A as a composite component in addition to zinc oxide and silicon oxide. Metal oxide A is an oxide containing one or more elements from among B, Ga, In, Tl, Sc, and Y.

[0011] In the present invention, the gas barrier layer preferably contains zinc oxide and silicon oxide, and further preferably contains metal oxide A. Preferred examples of metal oxide A include oxides such as B (boron), gallium (Ga), indium (In), thallium (Tl), scandium (Sc), and yttrium (Y). By including silicon oxide and metal oxide A, the crystal growth of zinc oxide is suppressed, the flexibility of the gas barrier layer is improved, crack formation in the film is suppressed, and a barrier film with high barrier properties and ease of handling is obtained. Note that when components are represented by element symbols below, oxides are included, and oxides include those that are not completely oxidized.

[0012] The zinc oxide content in the composite oxide film is preferably 57% by mass or more, more preferably 60% by mass or more, even more preferably 65% ​​by mass or more, particularly preferably 68% by mass or more, and most preferably 70% by mass or more, in terms of mass percent. The zinc oxide content in the film is preferably 97% by mass or less, more preferably 93% by mass or less, even more preferably 90% by mass or less, particularly preferably 87% by mass or less, and most preferably 85% by mass or less, in terms of atomic percent. Furthermore, in the embodiment containing aluminum oxide, the zinc oxide content in the composite oxide film is preferably 45 atomic percent or more, more preferably 50 atomic percent or more, preferably 97 atomic percent or less, and more preferably 90 atomic percent or less, in terms of atomic percent. Furthermore, in the embodiment containing metal oxide A, the zinc oxide content in the composite oxide film is preferably 30 atomic percent or more, more preferably 40 atomic percent or more, preferably 97 atomic percent or less, and more preferably 90 atomic percent or less. By setting the content within the above range, crystal growth and defects in the composite oxide film are suppressed, flexibility is improved, and high barrier properties can be ensured.

[0013] The silicon dioxide content in the composite oxide film is preferably 2% by mass or more, more preferably 7% by mass or more, even more preferably 10% by mass or more, particularly preferably 13% by mass or more, and most preferably 15% by mass or more, in terms of mass percent. The silicon dioxide content is preferably 38% by mass or less, more preferably 33% by mass or less, even more preferably 30% by mass or less, particularly preferably 27% by mass or less, and most preferably 25% by mass or less, in terms of atomic percent. Furthermore, the silicon dioxide content in the composite oxide film is preferably 2.5 atomic percent or more, more preferably 5 atomic percent or more, preferably 50 atomic percent or less, and more preferably 40 atomic percent or less, in terms of atomic percent. By keeping the content within the above range, crystal growth and defects in the composite oxide film are suppressed, resulting in densification, good flexibility, and high barrier properties.

[0014] The aluminum oxide content in the composite oxide film is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1% by mass or more, particularly preferably 1.5% by mass or more, and most preferably 2% by mass or more, in terms of mass percent. The aluminum oxide content is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 6% by mass or less, particularly preferably 5% by mass or less, and most preferably 4% by mass or less. Furthermore, the aluminum oxide content in the composite oxide film is preferably 0.05 atomic percent or more, more preferably 0.1 atomic percent or more, preferably 10 atomic percent or less, and more preferably 8 atomic percent or less, in terms of atomic percent. Crystal growth and defects in the composite oxide film are suppressed, resulting in densification, good flexibility, and high barrier properties.

[0015] The content of metal oxide A in the composite oxide film containing metal oxide A is preferably 0.05 atomic percent or more, more preferably 0.50 atomic percent or more, even more preferably 1 atomic percent or more, particularly preferably 1.5 atomic percent or more, and most preferably 2 atomic percent or more, in terms of atomic percent. The content of metal oxide A is preferably 35 atomic percent or less, more preferably 30 atomic percent or less, even more preferably 25 atomic percent or less, particularly preferably 20 atomic percent or less, and most preferably 10 atomic percent or less. Crystal growth and defects in the composite oxide film are suppressed, resulting in densification, good flexibility, and high barrier properties.

[0016] The gallium oxide content in the composite oxide film containing gallium oxide, a suitable example of metal oxide A, is preferably 0.05 atomic% or more, more preferably 0.50 atomic% or more, even more preferably 1 atomic% or more, particularly preferably 1.5 atomic% or more, and most preferably 2 atomic% or more. The gallium oxide content is preferably 35 atomic% or less, more preferably 30 atomic% or less, even more preferably 25 atomic% or less, particularly preferably 20 atomic% or less, and most preferably 10 atomic% or less. Crystal growth and defects in the composite oxide film are suppressed, resulting in densification, good flexibility, and high barrier properties.

[0017] The above content is calculated by measuring the elements in the composite oxide film using ICP, etc., and assuming that elements other than oxygen are oxides in their most stable state. The content can be expressed in mass percent or atomic percent. For example, if zinc, silicon, and aluminum are detected, the zinc oxide content in mass percent is calculated as: Mass of zinc oxide (ZnO) / [Mass of zinc oxide (ZnO) + Silicon oxide (SiO) ２ ) mass + aluminum oxide (Al ２ O ３ It can be calculated as [mass of ) × 100. Furthermore, the content of each component in atomic percent can be calculated based on the atomic ratio of each element when the total number of atoms of zinc, silicon, and aluminum is set to 100. Moreover, if an element constituting the metal oxide A is detected instead of aluminum, that element can be converted to the corresponding oxide and the mass percent or atomic percent can be calculated in the same way.

[0018] The thickness of the composite oxide film is preferably 15 nm or more, more preferably 25 nm or more, even more preferably 30 nm or more, particularly preferably 35 nm or more, and most preferably 40 nm or more. The thickness of the oxide film is preferably 70 nm or less, more preferably 60 nm or less. By setting the thickness within the above range, the barrier properties can be increased, cracks are less likely to occur, and it is also advantageous in terms of productivity and economy.

[0019] The surface resistance of the composite oxide film is preferably 1×10 １３ Ω / sq. or more, more preferably 1×10 １４ Ω / sq. or more, and still more preferably 1×10 １５ Ω / sq. or more. By setting the surface resistance to the above value or higher, when a conductive circuit formed of a transparent conductive layer or the like is provided on the composite oxide film of the barrier film, short-circuiting is less likely to occur and a fine circuit can be formed. A higher surface resistance is preferable. Although there is a limitation of the measuring instrument, the upper limit is not fixed, but 1×10 １８ Ω / sq. is practically preferable in practice. It should be noted that surface resistance measuring instruments compatible with high resistance are commercially available, and the surface resistance can be measured using these instruments. In the case where the gas barrier layer has a multilayer structure described later, it is preferable that the surface resistance of the gas barrier layer satisfies the above requirement.

[0020] Examples of the method for forming the composite oxide film include, but are not particularly limited to, sputtering, vacuum deposition, ion plating, CVD, and atomic layer deposition (ALD). Among these methods, sputtering is preferable from the viewpoints that a denser film with higher barrier properties can be obtained and productivity is high.

[0021] The gas barrier layer may have a multilayer structure as long as it contains at least one layer of the composite oxide film. Layers other than the above-mentioned composite oxide film may be a silicon oxide film, an aluminum oxide film, a silicon oxide-aluminum oxide composite film, or a composite film of metal oxides containing silicon oxide and / or aluminum oxide as a main component, which are mentioned as the above composite components. The gas barrier layer may also be a laminate of films that fall within the scope of the above-mentioned zinc oxide-based composite oxide films and have different compositions. Even in these cases, at least one layer is preferably a composite oxide film obtained by adding Si and Al to zinc oxide. In addition, in another embodiment, at least one layer may be a composite oxide film obtained by adding Si and the above-mentioned metal oxide A (preferably gallium oxide) to zinc oxide.

[0022] In the case of a multilayer structure, each layer may be provided by a method suitable for each layer from among the methods listed as methods for forming the composite oxide film. For example, a silicon oxide film may be provided by vacuum deposition and the composite oxide film may be provided on top of it by sputtering. Also, from the standpoint of productivity, multilayer gas barrier layers with different film compositions may be provided in the same sputtering apparatus by changing the composition of the sputtering target. In one embodiment, all or part of the aluminum oxide contained in the sputtering target may be replaced with gallium oxide. Also, in one embodiment, all or part of the aluminum oxide contained in the sputtering target may be replaced with metal oxide A (an oxide containing one of the elements B, Ga, In, Tl, Sc, or Y, or an oxide containing multiple elements).

[0023] When the gas barrier layer has a multilayer structure, the thickness of the gas barrier layer is preferably 20 nm or more, more preferably 30 nm or more, and even more preferably 40 nm or more. The thickness of the gas barrier layer is preferably 150 nm or less, more preferably 120 nm or less, and even more preferably 100 nm or less. By setting the thickness within the above range, the barrier properties can be increased and cracks are less likely to occur.

[0024] In addition, a resin composition coating layer containing an inorganic layered compound may be provided as an undercoat and overcoat of the gas barrier layer, or a barrier coating layer such as a sol-gel coating layer may be provided. In the present invention, these wet process barrier coating layers may be provided. However, the thickness of the multilayer gas barrier layer in this disclosure does not include the thickness of these wet process coating layers, and the total thickness of the inorganic oxide film, which is laminated in contact with or continuously laminated in contact with the zinc oxide-based composite oxide film by a dry process, is defined as the thickness of the multilayer gas barrier layer.

[0025] [Transparent Plastic Film Substrate] There are no particular restrictions on the transparent plastic film substrate used to provide the gas barrier layer, as long as it is a transparent resin film. Examples of resins that can be used include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate, polyethylene-2,6-naphthalate, polypropylene terephthalate, polybutylene terephthalate, and polyethylene furanoate; polyamides such as nylon 6, nylon 4, nylon 66, and nylon 12; polyimide, polyamide-imide, polyethersulfone, polyetheretherketone, polycarbonate, polyarylate, cellulose propionate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyetherimide, polyphenylene sulfide, polyphenylene oxide, polystyrene, syndiotactic polystyrene, norbornene polymers, etc. In the following, the transparent plastic film substrate may simply be referred to as the film substrate.

[0026] Films can be prepared using methods optimal to suit the properties of these resins, and may be stretched in the longitudinal and / or widthwise directions as needed. Film preparation methods include melting and kneading the resin and extruding it into a sheet on a cooling roll, calendering, and solution film formation. Typical stretching methods include stretching in the longitudinal direction using rolls with different peripheral speeds, and stretching in the widthwise using a tenter. Stretching in both the longitudinal and widthwise directions may also be performed using a tenter. After stretching, heat setting may be performed. In the case of polyimides, a precursor (e.g., polyamic acid) may be formed in solution, and then the reaction may be completed to produce a polyimide film.

[0027] Among these organic polymer resins, polyethylene terephthalate (PET), polypropylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene-2,6-naphthalate (PEN), syndiotactic polystyrene (SPS), norbornene polymer (COP), polycarbonate (PC), and polyarylate (PAR) are preferred. Furthermore, these resins may be copolymerized with small amounts of other monomers in addition to the monomer represented by the resin name, or blended with other organic polymers. Moreover, PET or PEN are preferred in terms of mechanical strength, transparency, solvent resistance, and weather resistance, and biaxially oriented films of PET or PEN are preferred. Among these, biaxially oriented films of PEN are preferred in that they tend to reduce the amount of outgassing, as will be discussed later. The reason for the low outgassing rate of biaxially oriented PEN films is not entirely clear, but possible reasons include their resistance to thermal decomposition compared to PET, the low volatility of low molecular weight substances (e.g., bishydroxyethyl naphthalate, cyclic oligomers, etc.), and the high barrier properties of PEN itself, which make it difficult for low molecular weight substances to migrate to the surface. However, the present invention is not limited to these reasons.

[0028] When PEN is used as the film substrate, the amount of naphthalenedicarboxylic acid (NDA) in the dicarboxylic acid component of the PEN constituting the film is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 98 mol% or more. Of course, 100 mol% is also preferable. In the glycol component of the PEN resin, the amount of ethylene glycol (EG) is preferably 95 mol% or more, more preferably 97 mol% or more, even more preferably 98 mol% or more, and particularly preferably 98.5 mol% or more. The amount of EG is preferably 100 mol% or less, more preferably 99.7 mol% or less, and even more preferably less than 99.5 mol%. In the production of PEN, it is difficult to completely prevent the ethylene glycol used as a raw material from dimerizing into diethylene glycol (DEG). The amount of DEG in PEN is preferably 5 mol% or less, more preferably 3 mol% or less, even more preferably 2 mol% or less, and particularly preferably 1.5 mol% or less. The amount of DEG component is preferably 0.1 mol% or more, more preferably 0.3 mol% or more, and even more preferably 0.5 mol% or more. By setting the composition of PEN within the above range, a biaxially oriented film can be produced that takes advantage of the heat resistance of PEN.

[0029] The intrinsic viscosity (IV) of the PEN constituting the film is preferably 0.4 dL / g or more, more preferably 0.45 dL / g or more, and even more preferably 0.5 dL / g or more. The IV is preferably 0.8 dL / g or less, more preferably 0.75 dL / g or less, even more preferably 0.7 dL / g or less, and particularly preferably 0.65 dL / g or less. By setting it within the above range, it is possible to increase the strength while suppressing thermal decomposition during film formation, such as during melt extrusion, making it easier to produce a film with less discoloration, and also making it easier to reduce outgassing.

[0030] The film substrate may contain resins other than PEN. Examples of resins other than PEN include the resins mentioned above, and other polyester resins may also be used. In the resin constituting the film substrate, PEN is preferably 90% by mass or more, more preferably 93% by mass or more, even more preferably 95% by mass or more, and particularly preferably 97% by mass or more. Of course, 100% by mass is also preferable.

[0031] The resin of the film substrate may contain various additives. Examples of additives include inorganic particles, heat-resistant polymer particles, alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, lightfast agents, ultraviolet absorbers, flame retardants, heat stabilizers, antioxidants, gelation inhibitors, and surfactants.

[0032] The film substrate may be a single layer or a multilayer structure. In the case of a multilayer structure, it is preferable to have 2 to 5 layers. When a multilayer structure is used, it is preferable to have a multilayer structure that includes or excludes the aforementioned additives. Specific examples include particle-containing layer / particle-free layer, particle-containing layer A / particle-containing layer B, particle-containing layer A / particle-containing layer B / particle-free layer, particle-containing layer A / particle-free layer / particle-containing layer B, organic stabilizer-free layer / organic stabilizer-containing layer / organic stabilizer-free layer, etc. Here, it is preferable that particle-containing layer A and particle-containing layer B differ in at least one of the types of particles they contain, particle size, or the amount of additive. For example, it is preferable that particle-containing layer A has a larger particle size or a higher content than particle-containing layer B. Organic stabilizers are a general term for alkali metal compounds, alkaline earth metal compounds, phosphorus compounds, antistatic agents, lightfasteners, ultraviolet absorbers, flame retardants, heat stabilizers, antioxidants, gelation inhibitors, etc., with ultraviolet inhibitors being particularly preferred. When the film substrate has a multilayer structure, it is preferable that at least one surface of the film substrate be a particle-free layer. By providing a gas barrier layer on the surface of the particle-free layer, surface roughness can be reduced, pinhole formation can be suppressed and gas barrier properties can be easily improved. Furthermore, when both surfaces are particle-containing layers, it is preferable to provide the gas barrier layer on the side with lower surface roughness, as described later. When the gas barrier layer is provided on the surface of the particle-containing layer of the film substrate, it is preferable to provide a planarizing coating layer, as described later, between the film substrate and the gas barrier layer.

[0033] Multilayer film substrates can be manufactured by co-extrusion. The multilayer structure of the film substrate described herein refers to the multilayer structure during the extrusion of the sheet-like material when manufacturing the film, and does not include layers provided by coatings such as the easy-adhesion layer described later.

[0034] Examples of particles used in film substrates include inorganic materials such as silica, calcium carbonate, talc, alumina, and zirconia, and organic materials such as styrene, acrylic, and melamine. The particle size of the particles used in the film substrate is preferably 0.005 μm or larger, more preferably 0.01 μm or larger, and even more preferably 0.02 μm or larger. This increases the slipperiness of the film. The particle size is preferably 3 μm or smaller, more preferably 1 μm or smaller, even more preferably 0.5 μm or smaller, and particularly preferably 0.3 μm or smaller. This reduces the haze of the film and also increases its transparency. Furthermore, it contributes to reducing the density of foreign matter, making it easier to improve barrier properties by reducing foreign matter on the film surface due to particle shedding and making it less likely for fine scratches to occur due to friction between films.

[0035] The particle content is preferably 50 ppm by mass or more, more preferably 100 ppm by mass or more, even more preferably 200 ppm by mass or more, and particularly preferably 250 ppm by mass or more. A higher content than the above can improve the film's slipperiness. The particle content is preferably 20,000 ppm by mass or less, more preferably 10,000 ppm by mass or less, even more preferably 8,000 ppm by mass or less, particularly preferably 6,000 ppm by mass or less, and most preferably 5,000 ppm by mass or less. A lower content than the above can reduce the film's haze and improve its transparency. Furthermore, it becomes easier to improve barrier properties by reducing surface foreign matter due to particle shedding and making it less prone to fine scratches caused by friction between films.

[0036] The particle content can be appropriately set depending on the particle size, taking into consideration slipperiness, transparency, and barrier properties. For example, when using particles of 1 μm or larger, the content is preferably 3000 ppm by mass or less, more preferably 2000 ppm by mass or less, and even more preferably 1000 ppm by mass or less. On the other hand, when the particle size is less than 1 μm, particularly 0.5 μm or less, the content is preferably 500 ppm by mass or more, more preferably 1000 ppm by mass or more, and even more preferably 1500 ppm or more. Furthermore, the particle-free layer is permitted to contain particles within a range that is substantially particle-free, for example, less than 50 ppm by mass.

[0037] The film substrate may be subjected to surface activation treatments such as corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment, electron beam irradiation treatment, or ozone treatment. Furthermore, the film substrate may have an easy-adhesion layer and / or an easy-slip layer provided on at least one surface for the purpose of improving adhesion with layers laminated on the film substrate, or for the purpose of improving the slipperiness of the film.

[0038] The thickness of the film substrate is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. A thickness greater than the above helps to suppress the reduction of barrier properties due to bending during handling, and the reduction of barrier properties due to impact after processing into solar cells, etc. It also provides appropriate rigidity to solar cells, etc., during and after processing, making them easier to handle. The thickness of the film substrate is preferably 200 μm or less, more preferably 170 μm or less, and even more preferably 150 μm or less. A thickness less than the above makes handling during processing easier and allows for thinner solar cells, etc.

[0039] The film substrate may have an easy-adhesion layer and / or an easy-slip layer. The easy-adhesion layer improves the adhesion between the film substrate and the undercoat layer, the planarization coat layer, functional layer, or gas barrier layer described later. The easy-slip layer provides slipperiness to the film and improves winding performance. Since the easy-slip layer is made by adding particles, etc., as described later, to create an uneven surface, it is preferable not to directly provide a gas barrier layer on the surface of the easy-slip layer. An easy-adhesion and easy-slip layer may also be provided by adding particles to the easy-adhesion layer to give it easy-slip properties (combining the functions of the easy-adhesion layer and the easy-slip layer). Hereafter, the easy-adhesion layer, easy-slip layer, and easy-adhesion and easy-slip layer will be collectively referred to as the easy-adhesion layer.

[0040] The easy-adhesion layer can be provided by coating a film substrate with a coating solution. The coating is preferably performed using an aqueous coating solution in an in-line method within the film manufacturing line. The thickness of the easy-adhesion layer is preferably 20 nm or more, more preferably 30 nm or more, with an upper limit of preferably 300 nm or less, and more preferably 200 nm or less. The thickness can be determined, for example, by observing a cross-section of the film with a transmission electron microscope (TEM) or scanning electron microscope (SEM), measuring the thickness at 10 or more random points, and taking the arithmetic mean.

[0041] It is preferable for the film substrate to contain particles in the surface layer, as this satisfies the film's slipperiness requirements and facilitates winding during manufacturing. When the surface layer of the film substrate does not contain lubricant particles, it is preferable to provide an easy-adhesion layer containing particles on the film substrate by inline coating. The easy-adhesion layer may be provided on both sides of the film substrate, but in order to achieve high barrier properties and meet the surface roughness standard (SRa 3 nm or less), it is preferable to provide the easy-adhesion layer containing particles on only one side and leave the other side as a film substrate surface without particles, or as a surface with an easy-adhesion layer without particles. The film substrate with a surface layer that does not contain lubricant particles may be a single-layer structure without lubricant particles, a multi-layer structure with particles in the intermediate layer (other than the surface layer), or a multi-layer structure where no layer contains particles. In particular, a configuration in which the film substrate does not contain particles and an easy-adhesion layer containing particles is provided on only one side of the film substrate is one of the preferred forms, as it can ensure the slipperiness necessary for winding and processing while achieving high smoothness and high transparency on the surface on which the barrier layer is provided.

[0042] Examples of resins used in the easy-adhesion layer include copolymerized polyester resins, polyurethane resins, and acrylic resins. Examples of polyurethane resins include polyester polyurethane, polyether polyurethane, and polycarbonate polyurethane. It is preferable that the easy-adhesion layer is crosslinked. Examples of crosslinking agents include isocyanate compounds, melamine compounds, epoxy compounds, oxazoline compounds, and carbodiimide compounds.

[0043] The easy-adhesion layer preferably contains particles. The type of particles used is the same as that used in the film substrate. The particle size of the particles used in the easy-adhesion layer is preferably 0.005 μm or larger, more preferably 0.01 μm or larger, and even more preferably 0.02 μm or larger. This ensures good slipperiness. The particle size is preferably 1 μm or smaller, more preferably 0.7 μm or smaller, and even more preferably 0.5 μm or smaller. This ensures good slipperiness.

[0044] The particle content in the easy-adhesion layer is preferably 1% by mass or more, more preferably 3% by mass or more. The particle content is preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less. By keeping the particle content within the above range, it is possible to improve the slipperiness while making it less likely for problems caused by the above particles to occur.

[0045] The easy-adhesion layer may use two or more particles with different particle sizes, and may also contain various additives such as antistatic agents and surfactants. The particle sizes of the particles in the film and each coating layer can be directly determined by cutting a cross-section of the film and observing it with a scanning electron microscope (SEM). Alternatively, if the added particles are a dispersion of a solvent or the like, they can be measured by laser diffraction, dynamic light scattering, or the like.

[0046] In this specification, the term "film substrate" may include the coating layer and functional layer described above and below, and when a case is specified that does not include the functional layer and coating layer, it is referred to as "film substrate raw material." However, the film substrate raw material may include the aforementioned easy-adhesion material.

[0047] The roughness (average arithmetic mean height: SRa) of at least one surface of the film substrate is preferably 3 nm or less, more preferably 2 nm or less, even more preferably 1.7 nm or less, even more preferably 1.5 nm or less, particularly preferably 1.3 nm or less, and most preferably 1.1 nm or less. By providing a barrier layer (inorganic oxide thin film) on a surface with an SRa of the above or less, pinholes are less likely to occur, high barrier properties can be achieved, and light scattering is reduced, resulting in excellent transparency. A lower surface roughness (SRa) is preferable, and there is no lower limit, but in terms of productivity, it is preferably 0.01 nm or more, more preferably 0.05 nm or more, even more preferably 0.1 nm or more, particularly preferably 0.2 nm or more, and most preferably 0.3 nm.

[0048] Furthermore, the average maximum peak height (SRp) of at least one surface of the film substrate is preferably 50 nm or less, more preferably 30 nm or less, even more preferably 25 nm or less, even more preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less. By providing a barrier layer (inorganic oxide thin film) on the surface with an SRp of the above or less, pinholes are less likely to occur in the barrier layer, and damage to the barrier layer during film handling can be reduced, thus achieving high barrier performance. A lower SRp is preferable, and there is no lower limit, but in terms of productivity, it is preferably 0.3 nm or more, more preferably 1.0 nm or more, even more preferably 2.0 nm or more, and particularly preferably 3.0 nm or more. The average arithmetic mean height (SRa) and average maximum peak height (SRp) are values ​​measured by a non-contact optical interference method, where five locations are measured to determine the arithmetic mean height and maximum peak height of each location, and the average value is the average of the values ​​obtained at the five locations.

[0049] To achieve the above-mentioned roughness range on at least one surface of the film substrate, the following methods can be used: • One surface of the film substrate roll is free of particles. • The particles on one surface of the film substrate roll are small in size.

[0050] Furthermore, a coating layer may be provided on at least one side of the film substrate raw material, and the surface of the coating layer may have the above-mentioned surface roughness. In particular, when the surface roughness of the film substrate raw material is large, it is preferable to provide a coating (planar coating) layer such that the surface roughness of the coating is within the above-mentioned range, and further to provide a barrier layer on top of this. The coating layer may be not only a planar coating layer but also an antistatic layer, and the planar coating layer may have an antistatic function. For this reason, an antistatic agent may be added to the planar coating layer, and an adhesion improver may be added to further improve the adhesion between the planar coating layer and the film substrate raw material or barrier layer, and an ultraviolet absorber may also be added. Furthermore, it may be a barrier coating layer produced by the wet process described above. Note that these single-layer or multi-layer coating layers provided between the film substrate raw material and the composite oxide film are sometimes collectively referred to as undercoat layers.

[0051] Resins that are preferably used in planar coating layers include those commonly used as coating resins, such as polyester, acrylic, polyurethane, polystyrene, polyamide, polyimide, polyamide-imide, and silicone. Among these, resins that harden by applying energy such as heating, ultraviolet irradiation, or electron beam irradiation are preferred, and curable resins such as silicone resin, acrylic resin, methacrylic resin, epoxy resin, and melamine resin are examples, and the above resins may also be hardened using a crosslinking agent. From the viewpoint of productivity, it is preferable to use an ultraviolet-curable resin as the main component. The coating layer is preferably transparent (uncolored), and in the case of polyimide and polyamide-imide, uncolored types called transparent polyimide and transparent polyamide-imide are preferred.

[0052] Examples of UV-curable resins include polyfunctional acrylate resins such as polyhydric alcohols like acrylic acid or methacrylic acid esters, and polyfunctional urethane acrylate resins synthesized from diisocyanates, polyhydric alcohols, and hydroxyalkyl esters of acrylic acid or methacrylic acid. If necessary, these polyfunctional resins can be copolymerized with monofunctional monomers, such as vinylpyrrolidone, methyl methacrylate, or styrene. Cationic epoxy resins are also preferred examples of UV-curable resins.

[0053] The thickness of the undercoat layer is preferably 0.1 μm or more, more preferably 0.3 μm or more, even more preferably 0.5 μm or more, and particularly preferably 0.8 μm or more. The thickness of the coating layer is preferably 15 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 6 μm or less. By making the thickness greater than the above, the influence of the roughness of the lower surface becomes less significant, and it becomes easier to control the surface roughness of the coating layer within the range of the surface roughness of the film substrate. On the other hand, if the thickness is less than the above, productivity is improved, curling and the like are less likely to occur, and the solvent can be easily removed and the amount of outgassing can be suppressed. The thickness of the coating layer can be determined by cutting a cross-section of the film substrate and observing it with an SEM or the like.

[0054] The surface of the undercoat layer or other surface may be subjected to the aforementioned surface activation treatment in order to improve adhesion with the barrier layer.

[0055] The roughness (SRa) of other surfaces of the film substrate is preferably 0.1 nm or more, more preferably 0.5 nm or more, and even more preferably 0.8 nm or more. Furthermore, the SRa of other surfaces is preferably 50 nm or less, more preferably 40 nm or less, even more preferably 30 nm or less, particularly preferably 20 nm or less, and most preferably 10 nm or less. Note that if the resin of the film substrate does not contain particles, but the easy-adhesion layer contains particles, the following effects are more likely to occur even if the SRa is low. In this case, the SRa of other surfaces may be 5 nm or less, 4 nm or less, or 3 nm or less.

[0056] The average maximum peak height (SRp) of the other surface of the film substrate is preferably 200 nm or less, more preferably 150 nm or less, even more preferably 100 nm or less, particularly preferably 80 nm or less, and most preferably 60 nm or less. The average maximum peak height (SRp) of the other surface of the film substrate is preferably 5 nm or more, more preferably 10 nm or more, even more preferably 20 nm or more, particularly preferably 30 nm or more, and most preferably 40 nm or more.

[0057] By making the surface roughness of other surfaces above the lower limit mentioned above, the slipperiness when winding the film substrate or barrier film is improved, making it less likely for wrinkles to form in the wound film and less likely for meandering to occur during winding. By making it below the upper limit mentioned above, the surface on which the barrier layer is applied, or the surface on which the barrier layer is applied, becomes less susceptible to scratches, and the barrier properties can be improved. Furthermore, the haze of the film substrate can be reduced and the transparency can be improved.

[0058] To ensure the roughness of other surfaces is within the above range, the following methods can be used: - One side of the film substrate raw material contains particles. - One side of the film substrate raw material is provided with an easy-adhesion layer containing the easy-adhesion particles, or an easy-slip layer is provided on top of the easy-adhesion layer. - If the roughness of other sides of the film substrate raw material is too high, the planarizing coating layer is provided. When a coating layer is provided on the film substrate, it is preferable to provide it on the easy-adhesion layer side of the film substrate. Furthermore, it is preferable that the following characteristics of the film substrate apply not only to the film substrate raw material, but also to the film substrate with the coating layer provided, i.e., the characteristics of the film substrate supplied to the process of forming a composite oxide film.

[0059] The outgassing of the film substrate is preferably 100 ppm or less, more preferably 80 ppm or less, even more preferably 60 ppm or less, and particularly preferably 40 ppm or less, 30 ppm or less, 20 ppm or less, and 15 ppm or less, in that order of decreasing preference. By reducing the outgassing amount of the film substrate to 100 ppm or less, the composite oxide film of the barrier layer can be made dense and have fewer defects. The components of outgassing are low molecular weight compounds contained in the film substrate. In order to reduce the amount of outgassing, it is preferable to set a low melt extrusion temperature when forming the film substrate raw material to suppress the generation of low molecular weight substances due to resin decomposition, to sufficiently remove the solvent if melt film formation is performed, and to remove volatile components by setting the temperature and airflow high in the stretching and heat setting processes. Furthermore, when a coating layer is provided, it is preferable to select a solvent that is easily volatile and to increase the temperature and airflow. When using UV-curable resins, it is preferable to reduce unreacted monomers by adjusting the amount of catalyst and irradiation conditions such as light, and to select highly reactive monomers or monomers with low volatility. It is also preferable to perform a degassing process before the process of forming the composite oxide film, which involves unwinding the film under reduced pressure and heating, and then winding it again.

[0060] A small amount of outgassing is preferable, with a lower limit of preferably 0.0 ppm or higher (above the detection limit). However, for productivity and economic reasons, it may be 1 ppm or higher, 3 ppm or higher, or 5 ppm or higher. The amount of outgassing is measured by gas chromatography. In the measurement, a film sample is heated to 200°C and the temperature is maintained. Components released from the film are trapped in a cooled trap section, and then the trap section is heated and introduced into the column. The amount of outgassing is defined as the components detected between 10 and 35 minutes after the start of heating of the trap section. This is because gases detected after 10 minutes of retention adversely affect the density of the composite oxide film, while components detected beyond 35 minutes are less likely to be released during film formation and are considered to have only a minor impact on film quality.

[0061] In the film formation process for creating a composite oxide film, the film substrate is wrapped around a cooling roll, and the composite oxide film is formed on the opposite side. Gas emission from the surface in contact with the cooling roll is minimal and has little effect on the film quality. Therefore, when there is a coating layer on the opposite side of the film formation surface, outgassing measurements are performed with the coating layer removed using sandpaper or a utility knife. The removal of the coating layer can be confirmed by ATR-IR or similar methods.

[0062] The film substrate preferably has few surface foreign matter particles. The amount of surface foreign matter is preferably 0.40 particles / mm ２ The following, and more preferably 0.20 pieces / mm ２ The following, and more preferably 0.10 pieces / mm ２ The following applies: By reducing the amount of surface foreign matter in the film substrate, the amount of embedded foreign matter in the gas barrier film can be reduced, thereby reducing the number of pinholes in the barrier layer and lowering the water vapor transmission rate. A low amount of surface foreign matter is preferable, and the lower limit is preferably 0 particles / mm². ２ However, for productivity and economic reasons, 0.01 pieces / mm ２ It may be greater than or equal to 0.1 pieces / mm ２ That's fine too.

[0063] Causes of surface foreign matter include residues of precipitated resin catalysts and adhesion of foreign matter during the film substrate manufacturing process. In the case of resin catalysts, for example, if antimony is used, reduced antimony tends to precipitate, so it is recommended to keep the amount of antimony element in the polyester film to preferably 250 ppm or less, more preferably 200 ppm or less. In addition, calcium, magnesium, etc. are used as electrostatic adhesives to make the molten sheet extruded into a sheet form adhere to the cooling roll, but it is also preferable to reduce the amount of electrostatic adhesive to prevent the precipitation of these substances.

[0064] Furthermore, foreign matter in the film substrate manufacturing process includes dust, and the amount of surface foreign matter can be reduced by improving cleanliness and preventing oligomers adhering to the tenter from falling off. In addition, when cutting the tenter gripping part or slitting the manufactured film substrate to the required width during film substrate manufacturing, chips may adhere to the film surface and become foreign matter. Therefore, it is preferable to increase the air suction around the blade during slitting to prevent chips from scattering.

[0065] The cleanliness of the film substrate manufacturing process and the coating process should be high, preferably class 7 or lower according to the ISO standard (the number after the class is 7 or less). The detachment of particles used in the film substrate is as described above. In addition, removing surface deposits by passing the film substrate through an adhesive roll when winding or unwinding is also a preferred method for reducing the amount of surface foreign matter. Washing with clean water is also preferred. Furthermore, it is also preferred to apply a surface-side protective film to the surface on which the inorganic oxide thin film is to be deposited. It is preferred that the surface-side protective film be peeled off in a clean environment before the inorganic oxide thin film is deposited, as this prevents the adhesion of foreign matter and reduces the amount of surface foreign matter by drawing in any foreign matter attached to the film substrate into the adhesive layer of the surface-side protective film. The peeling force of the surface-side protective film should preferably be 5 to 300 mN / 25 mm when attached to an acrylic (PMMA) plate. Within this range, surface foreign matter can be effectively removed, and a portion of the adhesive layer is less likely to remain on the surface on which the inorganic oxide thin film is deposited. Examples of surface-side protective films include polyethylene, polypropylene, and other polyolefin films with an adhesive layer, as well as polyester films. Generally, commercially available masking films can be used. The environment in which the surface-side protective film is bonded is preferably Class 6 or lower. The environment in the slitting process to the required width is also preferably Class 6 or lower. To prevent chips from adhering to the surface where the inorganic oxide thin film is to be deposited, slitting to the required width with the surface-side protective film bonded is also a preferred method.

[0066] The film substrate is preferably transparent. The light transmittance of the film substrate is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. A higher light transmittance is preferable because it improves the power generation efficiency of the solar cell and the appearance of the display. While a higher light transmittance of the film substrate is preferable, from the standpoint of productivity, it is preferably 99.5% or less, more preferably 99% or less, and even more preferably 98% or less.

[0067] The haze of the film substrate is preferably 3% or less, more preferably 2% or less, and even more preferably 1.5% or less. Low haze is preferable because it provides excellent transparency, which allows for uniform light exposure to the power generation layer and increases the amount of light entering the power generation layer in solar cell applications, and enables the achievement of a good appearance in display applications. While a low haze is preferable, from the standpoint of productivity, it is preferably 0.1% or more, more preferably 0.3% or more, and even more preferably 0.5% or more.

[0068] The color difference b value of the film substrate is preferably 2 or less, and more preferably 1.5 or less. The color difference b value is preferably -2 or more, and more preferably -1.5 or more. When the color difference b value is within the above range, coloration is greatly reduced, which is preferable because it can improve the power generation efficiency of solar cells and the appearance of displays. In this way, by setting the light transmittance, haze, and color difference b value within the above range, a barrier film suitable for various applications, especially in the fields of displays and solar cells, can be made.

[0069] The thermal shrinkage rate of the film substrate at 150°C is preferably 2% or less in both the MD and TD directions, more preferably 1.5% or less, even more preferably 1.2% or less, and particularly preferably 1% or less. The thermal shrinkage rate at 150°C is preferably -1% or more, more preferably -0.5% or more, and even more preferably 0% or more. A negative value indicates expansion. When the thermal shrinkage of the film substrate is within the above range, it is preferable because cracks are less likely to form in the barrier layer even if the film temperature rises when the barrier layer is formed, thus preventing deterioration of the barrier properties, and because film deformation due to heat during the processing step is prevented, ensuring the flatness of the film.

[0070] [Method for Manufacturing Film Substrate] The most preferred example used in the present invention, a method for manufacturing a biaxially oriented polyester film, is shown below. A polyester film is obtained by melt-extruding a polyester resin, which is the raw material, into a film shape, cooling and solidifying it in a casting drum to obtain an unstretched film, stretching this unstretched film biaxially in the flow direction (MD direction) and width direction (TD direction) at a magnification of 2.0 to 5.0 times at Tg to (Tg + 60) °C, and then heat-fixing it at a temperature of (Tm - 100) to (Tm - 5) °C for 1 to 100 seconds to obtain the desired film. Stretching is preferably performed by an area magnification of 9 to 20 times. Stretching can be performed by commonly used methods, such as a roll method or a tenter method, and the MD and TD directions may be stretched simultaneously or sequentially. In the case of sequential stretching, it is preferable to stretch in the MD direction using a roll, and then tenter stretch in the TD direction. When providing an easily adhesive layer in-line, it is preferable to apply the coating solution to a uniaxially oriented film stretched in one direction during the sequential stretching process, and then stretch it in the other direction and heat-set it. Here, Tg represents the glass transition temperature of the polymer, and Tm represents the melting point of the polymer. Further relaxation treatment may be performed, preferably in the range from the heat-setting temperature -80°C (however, 100°C or higher is preferable) to the heat-setting temperature. The relaxation rate is preferably 0.5 to 10%. The relaxation treatment may also be performed off-line after the film has been wound up and unwound. After that, a coating layer may be provided as needed.

[0071] In one embodiment, it is preferable to suppress resin decomposition to reduce outgassing in order to achieve a low amount of outgassing. For this purpose, it is preferable to avoid the resin temperature becoming too high or the high temperature state continuing for a long time during the extrusion process. The melt extrusion temperature is preferably Tm or more and Tm + 30°C or less, and preferably Tm + 25°C or less. Specifically, in the case of PET, it is preferably less than 295°C, more preferably less than 290°C, and even more preferably 287°C or less. In the case of PEN, it is preferably less than 310°C, more preferably less than 305°C, and even more preferably 302°C or less. The residence time from the extruder outlet to the die outlet is preferably 15 minutes or less, more preferably 10 minutes or less, and even more preferably 7 minutes or less.

[0072] [Method for Manufacturing Gas Barrier Film] The method for forming a zinc oxide-based composite oxide film on at least one surface of a film substrate is not particularly limited, but a preferred method, the sputtering method, will be explained with reference to Figure 2. In order to manufacture gas barrier films with high productivity, it is preferable to use a so-called roll-type sputtering apparatus in which the film 6 is unwound from a film roll, the film is placed against a part of a cooled center roll 7 to form a film on the side of the film opposite to the center roll, and then the film is wound up into the shape of a film roll. A mass flow controller can be used in the film formation atmosphere to introduce an inert gas and oxygen gas, and a zinc oxide-based composite oxide target 9 can be used to adjust the thickness of the composite oxide film to a desired range, thereby forming a composite oxide film on the film 6. To improve production efficiency, multiple targets may be set along the direction of film flow. The target may contain zinc oxide, silicon oxide and aluminum oxide, or it may contain zinc oxide, silicon oxide and the metal oxide A. The target may contain zinc oxide and silicon oxide, and may also contain gallium oxide. Furthermore, a hydrogen atom-containing gas (such as hydrogen, ammonia, or a mixture of hydrogen and argon; however, water is excluded) may be introduced into the film deposition atmosphere. Moisture in the film deposition atmosphere is a factor that degrades film quality and causes barrier properties and discoloration, so it is effective to suppress the amount of moisture. The central value (the value midway between the maximum and minimum) of the ratio of moisture pressure to inert gas in the film deposition atmosphere during sputtering onto a film roll should be 7.00 × 10⁻⁶. －３ The following control is preferable because it suppresses the deterioration of film quality. The central value of the ratio of water pressure to inert gas is more preferably 5.00 × 10⁻⁶. －３ The following, and more preferably 3.00 × 10 －３The following applies. In controlling the amount of moisture, in addition to selecting the exhaust system of the sputtering machine, such as a rotary pump, turbomolecular pump, or cryopump, it is preferable to take one or more measures to reduce the amount of moisture released from the film when forming the composite oxide film, such as performing the bombardment process described below, managing the height difference of the unevenness on the end face of the film roll as described below, or attaching a back-side protective film with low water absorption to the opposite side of the surface on which the composite oxide film is formed. Considering the economic feasibility of using a general-purpose vacuum pump and the number of vacuum pumps to be installed, the center value of the ratio of moisture pressure to inert gas is 1.0 × 10⁻⁶. －５ The above is desirable.

[0073] Furthermore, it is preferable to include a degassing process before sputtering. After unwinding the film from the unwinding roll, the outgassing components can be reduced in advance by exposing it to a vacuum for a certain period of time. At this time, the outgassing effect can be further enhanced by heating it using an infrared heater or a temperature-controlled roll.

[0074] Furthermore, it is preferable to deposit a composite oxide film on the film substrate at a film temperature of 0°C or lower during sputtering. The film temperature is more preferably -5°C or lower, and even more preferably -8°C or lower. The film temperature during deposition is controlled by the temperature of the center roll. The center roll is cooled by a refrigerant cooled by a temperature controller. Therefore, the film temperature can be substituted with the temperature of the refrigerant set by the temperature controller. By keeping the film temperature below 0°C, the release of impurity gases such as water and organic gases from the film is suppressed, preventing a deterioration of film quality. In addition, effects such as reducing thermal deformation during sputtering and damage to the barrier layer and maintaining the flatness of the film can be obtained. Considering the economic feasibility of using a general-purpose temperature controller, a film temperature of -40°C or higher is desirable during sputtering.

[0075] The moving film travels in partial contact with the surface of the center roll. Preferably, the moving film is in contact with more than one-quarter of the center roll's circumference, and more preferably, more than one-third. A sputtering target for a composite oxide is placed on the opposite side of the film traveling on the center roll, and a thin film of the composite oxide is deposited and laminated onto the surface of the film.

[0076] To achieve a practical level of total light transmittance in the gas barrier film, it is desirable to add oxygen gas during sputtering. The partial pressure of the oxygen gas is preferably 1 mPa or more, more preferably 3 mPa or more, even more preferably 5 mPa or more, and particularly preferably 10 mPa or more. Alternatively, the partial pressure of the oxygen gas is preferably 300 mPa or less, more preferably 250 mPa or less, even more preferably 200 mPa, particularly preferably 100 mPa or less, and most preferably 50 mPa or less.

[0077] Regarding the moisture content when depositing composite oxide films, it is preferable to actually observe the moisture content during film formation, rather than the ultimate vacuum level, for the following two reasons.

[0078] One reason for this is that when the film substrate is heated by sputtering, moisture is released from the film substrate. As a result, controlling the moisture pressure during film formation contributes more accurately to controlling the film quality than measuring the ultimate vacuum level in the deposition atmosphere.

[0079] The second reason stems from the behavior of the film when it is fed into the vacuum chamber in roll form. When a film roll is fed into the vacuum chamber, dewatering progresses easily in the outer layer, but moisture tends to remain in the inner layer. As the roll is unwound during film formation, the inner layer, which contains a lot of moisture, is exposed, increasing the amount of moisture in the film formation atmosphere. Therefore, in this invention, it is preferable to continuously observe and control the ratio of moisture pressure to inert gas in the atmosphere during sputtering.

[0080] When employing pulsed DC magnetron sputtering, the pulse frequency during sputtering is preferably 60 to 150 kHz. Furthermore, the pulse width is preferably 1.3 μs or greater. In addition, to maintain a good film deposition rate, the pulse width is preferably 10 μs or less.

[0081] A lower pulse frequency is preferable. By setting the pulse frequency to 150 kHz or less, the number of excessive voltage spikes immediately after voltage application to the sputtering target is suppressed. This reduces the energy of the noble gases colliding with the zinc oxide composite film, thereby reducing damage to the film, increasing its density, and improving its barrier properties. On the other hand, when the pulse frequency is 60 kHz or higher, the discharge becomes stable, suppressing the occurrence of arc discharge and ensuring high barrier properties.

[0082] By setting the pulse frequency to 150 kHz or less, damage to the zinc oxide-based composite oxide film can be suppressed, and high barrier properties can be ensured. In addition, increasing the pulse width makes it easier to stabilize the pulsed DC magnetron sputtering method. By setting the pulse width to 1.3 μs or more, the pulsed DC magnetron sputtering method can be stabilized, damage due to arc discharge can be suppressed, and high barrier properties can be ensured.

[0083] Before forming the composite oxide film, it is desirable to pass the film substrate through a bombardment process. A bombardment process involves applying a voltage and discharging a discharge in the presence of an inert gas such as argon alone, or a mixture of a reactive gas such as oxygen and an inert gas, to generate plasma. Specifically, it is desirable to bombard the surface of the film substrate by RF sputtering using a stainless steel (SUS) target. Because the film substrate is exposed to plasma during the bombardment process, moisture and organic components are removed from the film substrate, reducing the amount of water and organic components released from the film substrate during film formation, thus improving the film quality of the composite oxide film, which is preferable. In addition, the bombardment process activates the layers in contact with the composite oxide film, improving the adhesion of the composite oxide film.

[0084] The film substrate for forming the composite oxide film is preferably wound into a film roll, and the height difference between the most convex and most concave points on the roll end face of the film roll is preferably 10 mm or less. More preferably 7 mm or less, and even more preferably 5 mm or less. A height difference of 10 mm or less is preferable because it suppresses the release of moisture and organic components from the film end face when the film roll is fed into the sputtering apparatus, maintaining the cleanliness of the film formation atmosphere, and thus improving the film quality of the composite oxide film. The lower limit of the height difference on the roll end face is 0, but in practical terms it may be 0.1 mm.

[0085] In a film substrate for forming a composite oxide film, it is also desirable to attach a back-side protective film with low water absorption to the side opposite the film-forming surface (back side). Attaching a back-side protective film with low water absorption makes it more difficult for gases such as water to be released from the back side of the film substrate during vacuum deposition, thus maintaining a low moisture partial pressure in the deposition atmosphere. This improves the film quality of the composite oxide film and the transparent conductive layer, making it preferable. Polyethylene, polypropylene, and cycloolefin are preferred substrates for the back-side protective film with low water absorption. Generally, commercially available masking films can be used as the back-side protective film.

[0086] [Gas Barrier Film] Gas barrier films are preferably made with a low amount of outgassing. In the film formation process of composite oxide films, volatile components in the film substrate are not completely removed, and a low amount of outgassing in a gas barrier film means that a dense composite oxide film with high barrier properties is obtained using a film substrate with a low amount of outgassing. Furthermore, as will be described later, as an example of processing the gas barrier film of the present invention, it is preferable to laminate a transparent conductive layer on at least one side of the obtained gas barrier film, and by reducing the amount of outgassing in the gas barrier film, it becomes easier to provide a transparent conductive layer with excellent conductivity and little coloration.

[0087] The outgassing amount of the gas barrier film is preferably 100 ppm or less, more preferably 80 ppm or less, and even more preferably 60 ppm or less, and particularly preferably 40 ppm or less, 30 ppm or less, 20 ppm or less, and 15 ppm or less, with the value decreasing in that order. A lower outgassing amount is preferable, but the lower limit is preferably 0.0 ppm or more (above the detection limit), and for productivity and economic reasons, it may be 1 ppm or more, 3 ppm or more, or 5 ppm or more. The outgassing amount of the gas barrier film can be measured in the same way as the outgassing amount of the film substrate.

[0088] The amount of embedded foreign matter in the gas barrier film is preferably 0.4 pieces / mm². ２ The following, and more preferably 0.3 pieces / mm ２ The following, and more preferably 0.2 pieces / mm ２ The following, and particularly preferably 0.1 pieces / mm ２ The following applies: Embedded foreign matter is likely to become a defect (micro-pinhole) in the barrier layer. Furthermore, not only are defects occurring during film formation, but the barrier layer is also prone to cracking at the location of the micro-foreign matter during handling of the gas barrier film, resulting in defects. In addition, when a transparent conductive layer is laminated on the barrier layer of the resulting gas barrier film, it is also likely to become a defect in the transparent conductive layer, and when the transparent conductive layer is micro-processed, the wiring is prone to breakage. Reducing the amount of embedded foreign matter in the gas barrier film to below the above limits makes these problems less likely to occur. It is preferable to have fewer embedded foreign matter in the gas barrier film, and the lower limit is preferably 0 pieces / mm². ２ However, for productivity and economic reasons, 0.01 pieces / mm ２ It may be greater than or equal to 0.1 pieces / mm ２ The above may also be applicable. The amount of embedded foreign matter in the gas barrier film can be measured by observation with an optical microscope. In this disclosure, foreign matter density refers to the number of embedded foreign matter particles per unit area (particles / mm²) calculated by embedded foreign matter evaluation. ２ ) refers to.

[0089] The surface roughness (average arithmetic mean height: SRa) of the gas barrier layer surface of the gas barrier film is preferably 3 nm or less, more preferably 2 nm or less, even more preferably 1.7 nm or less, even more preferably 1.5 nm or less, particularly preferably 1.3 nm or less, and most preferably 1.1 nm or less. Reducing the surface roughness (SRa) suppresses the occurrence of pinholes and achieves high barrier performance, as well as contributing to the realization of excellent transparency by suppressing light scattering. The lower limit is not limited, but in terms of productivity, it is preferably 0.01 nm or more, more preferably 0.05 nm or more, even more preferably 0.1 nm or more, particularly preferably 0.2 nm or more, and most preferably 0.3 nm or more.

[0090] The average maximum peak height (SRp) of the gas barrier layer is preferably 50 nm or less, more preferably 30 nm or less, even more preferably 25 nm or less, even more preferably 20 nm or less, particularly preferably 15 nm or less, and most preferably 10 nm or less. By controlling SRp to be below the above upper limit, physical damage to the barrier layer can be reduced and high barrier performance can be maintained. A lower SRp is preferable, and there is no lower limit, but in terms of productivity, it is preferably 0.3 nm, more preferably 1.0 nm or more, even more preferably 2.0 nm or more, and particularly preferably 3.0 nm or more. The roughness of the gas barrier layer can be measured in the same way as for the film substrate.

[0091] By keeping the surface roughness of the gas barrier layer of the gas barrier film below the above upper limit, the barrier properties of the gas barrier film can be improved, and defects in the gas barrier layer during handling become less likely. Furthermore, when a transparent conductive layer is laminated on the barrier layer of the resulting gas barrier film, defects in the transparent conductive layer become less likely, and haze can be reduced, enabling high transparency. While a lower surface roughness is preferable, the above is preferable for productivity and economic reasons.

[0092] The water vapor transmission rate of the gas barrier film at 85°C and 85% RH is preferably 1 × 10⁻⁶. －１ g / m ２Less than / day, more preferably 0.8 × 10 －１ g / m ２ / day or less, and more preferably 0.7 × 10 －１ g / m ２ It is less than / day. The water vapor transmission rate is 1 × 10⁻⁶. －１ g / m ２ By reducing the water vapor transmission rate to less than 10 / day, the electronic device can operate stably for a long period of time, even when used in electronic devices that require a high level of barrier performance. The gas barrier film of the present invention exhibits a low water vapor transmission rate even if the barrier layer is a single layer. It is preferable that the water vapor transmission rate of the gas barrier film, which is a single-layer barrier layer, is as described above. A lower water vapor transmission rate is preferable, but for productivity and economic reasons, it is preferably 0.01 × 10 －４ g / m ２ / day or more, and more preferably 0.05 × 10 －４ g / m ２ / day or more, and more preferably 0.1 × 10 －４ g / m ２ It is more than / day.

[0093] The helium gas permeability of the gas barrier film at 23°C is preferably 1.0 × 10⁻⁶. －１４ mol / m ２ - Less than s·Pa, more preferably 0.8 × 10 －１４ mol / m ２ The coefficient of flux is s and Pa, and more preferably 0.7 × 10⁻⁶. －１４ mol / m ２ The pressure is s・Pa, and is particularly preferably 0.6 × 10 －１４ mol / m ２ The pressure is s·Pa. The lower the helium gas permeability, the denser and less defective the film is. A lower helium gas permeability is preferable, but for productivity and economic reasons, it is preferably 0.01 × 10⁻⁶. －１４ mol / m ２ - s·Pa or higher, more preferably 0.1 × 10 －１４ mol / m ２ It is sPa.

[0094] The light transmittance of the gas barrier film is preferably 80% or more, more preferably 82% or more, even more preferably 83% or more, particularly preferably 84% or more, and most preferably 86% or more, when the transparent conductive layer described later is not laminated. By achieving the above levels or higher, for example, when used in a solar cell, the power generation efficiency is increased, and when used in an image display device, a bright and clear image can be produced. A higher light transmittance is preferable, preferably 100% or less, but for productivity and economic reasons, it is more preferably 98% or less, even more preferably 97% or less, particularly preferably 96% or less, and most preferably 95% or less.

[0095] The color difference b value of the gas barrier film is preferably -2.5 or higher, more preferably -2.2 or higher, even more preferably -2 or higher, and particularly preferably -1.8 or higher. Furthermore, the color difference b value is preferably 2 or less, more preferably 1.7 or less, even more preferably 1.5 or less, and particularly preferably 1.2 or less. By setting the color difference b value within the above range, for example, when used in solar cells, the power generation efficiency is increased; when applied to windows, the color is less unnatural; and when used in image display devices, images with excellent color reproduction can be produced.

[0096] The dimensional change rate of the gas barrier film at 120°C for 30 minutes is preferably -1.0 to 1.0% in both the film's flow direction and width direction. This range is preferable because it reduces the force on the zinc oxide composite film when the gas barrier film is heat-treated in post-processing steps, making it less prone to cracking; prevents cracking in the zinc oxide composite film even when the film's temperature rises after deposition, thus preventing deterioration of barrier properties; and prevents thermal deformation of the film during post-processing steps, ensuring the film's flatness. More preferably, the dimensional change rate in either the film's flow direction or width direction is -0.5 to 0.5%, even more preferably -0.2 to 0.2%, and particularly preferably both are within this range.

[0097] A functional layer may be laminated onto the gas barrier film. Examples of functional layers include a hard coat layer, anti-reflective layer, low-reflection layer, anti-glare layer, anti-fouling layer, antistatic layer, and ultraviolet absorption layer. By providing these functional layers, for example, when the gas barrier film is used in a solar cell, effects such as increasing power generation efficiency, maintaining power generation efficiency, reducing glare and minimizing the impact on the surrounding environment, and preventing degradation can be obtained. When used in an image display device, effects such as clearer images and prevention of degradation can be obtained. The resin used in the functional layer is the same as the resin preferably used in the planarization coat layer, and the aforementioned ultraviolet-curable resin can preferably be used in the hard coat layer, anti-reflective layer, low-reflection layer, and anti-glare layer. In the anti-reflective layer and low-reflection layer, particles such as metal oxides may be added to adjust the refractive index. In the anti-glare layer, resin particles may be added to form surface irregularities. Examples of anti-fouling layers include a resin coat layer with titanium dioxide added, an alkoxylane-based or perhydropolysilazane-based coat layer, a fluororesin-based coat layer, and a silicone-based coat layer. Examples of antistatic layers include resin coating layers to which ionic surfactants, conductive polymers, conductive particles, etc., are added. Examples of ultraviolet absorbing layers include resin coating layers to which organic or inorganic ultraviolet absorbers are added. The functional layer may also be the aforementioned barrier coating layer.

[0098] The functional layer is preferably provided on at least one side of the gas barrier film, which may be the side of the film substrate opposite to the gas barrier layer, the side of the gas barrier layer opposite to the film substrate, or both sides, but it is preferable that it is provided on the side of the film substrate opposite to the gas barrier layer. Furthermore, if provided on both sides, each side may be a different functional layer. In addition, multiple functional layers may be laminated. These layers can be any known type without particular limitation.

[0099] The thickness of the functional layer can be optimized according to the function of the functional layer, but is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The thickness of the functional layer is preferably 15 μm or less, more preferably 10 μm or less, even more preferably 8 μm or less, and particularly preferably 6 μm or less. By keeping it within the above range, the function of the functional layer can be effectively exerted and it will be easy to handle. When the functional layer is provided on a film substrate, it is preferable to provide the functional layer on the side where the easy-adhesion layer is provided. Furthermore, the preferred gas barrier film properties listed above are also the same for gas barrier films with a functional layer. In this specification, the term "overcoat layer" refers to a wet coat layer provided on the side of the composite oxide film opposite to the film substrate side, and the term "backcoat layer" refers to a wet coat layer provided on the side of the film substrate opposite to the composite oxide film side. Furthermore, the term "undercoat layer" refers to a coat layer provided between the film substrate and the composite oxide film.

[0100] [Laminated Gas Barrier Film with Transparent Conductive Layer] The gas barrier film of the present invention is preferably used as a gas barrier film alone for various applications, but it is also preferable to further provide a transparent conductive layer and use it as a substrate for a conductive film. Conventionally, in electronic devices that require high barrier properties, a cell (for example, a solar cell, an organic EL cell, etc.) was fabricated by providing a structure that performs the function of the electronic device on a transparent conductive film, and this cell was sealed using a gas barrier film. However, because the gas barrier film of the present invention has extremely high gas barrier properties, an electronic device can be made by providing a transparent conductive layer on the gas barrier film without using a separate transparent conductive film. As a result, it is possible to make the film thinner, and it is advantageous in terms of productivity, cost, and resource conservation. Furthermore, it is also advantageous in terms of flexibility as it is less prone to creasing and peeling of layers.

[0101] The transparent conductive layer may be provided on the gas barrier layer side of the gas barrier film, or on the transparent plastic film side. It may also be provided on both sides. The transparent conductive layer can be any known transparent conductive layer without limitation, such as metal oxide conductive layers such as indium-tin oxide, coating layers with dispersed needle-shaped fillers such as carbon nanotubes or metals, coating layers of conductive polymers, mesh-like printed materials of conductive paste, or mesh-like materials etched from copper or the like.

[0102] Specific materials for metal oxide conductive layers include indium oxide, tin oxide, zinc oxide, indium-tin composite oxide, tin-antimony composite oxide, zinc-aluminum composite oxide, and indium-zinc composite oxide. Of these, indium-tin composite oxide (ITO) is preferred from the viewpoint of environmental stability and circuit processing properties such as wiring.

[0103] The surface resistance of the transparent conductive layer is preferably 200 Ω / sq. or less, more preferably 100 Ω / sq. or less. However, when used in solar cells, it is preferably 50 Ω / sq. or less, more preferably 40 Ω / sq. or less, even more preferably 30 Ω / sq. or less, particularly preferably 20 Ω / sq. or less, and most preferably 15 Ω / sq. or less. By keeping it within the above range, power generation efficiency can be increased. A lower surface resistance of the transparent conductive layer is preferable, and in the case of metal needle-shaped fillers, metal thin film meshes (etched), values ​​as low as 0.01 Ω / sq. are possible, so there is no particular lower limit. For example, when the transparent conductive layer is metal oxide-based, it is preferably 1 Ω / sq. or more, but in terms of economy and ensuring high transparency, it may be 3 Ω / sq. or more, or even 5 Ω / sq. or more.

[0104] The thickness of the transparent conductive layer is preferably in the range of 1 to 2000 nm, more preferably 5 to 1000 nm, and an appropriate range can be set depending on the type of transparent conductive layer. For example, when the transparent conductive layer is metal oxide based, from the viewpoint of achieving both low resistance and high transparency, it is preferably 50 to 180 nm, and more preferably 70 to 150 nm.

[0105] When the transparent conductive layer is an ITO layer, the tin oxide concentration is preferably 5% by mass or more, more preferably 6% by mass or more, and even more preferably 8% by mass or more. The tin oxide concentration is preferably 16% by mass or less, more preferably 14% by mass or less, and even more preferably 12% by mass or less. By keeping it within the above range, high conductivity is more easily achieved.

[0106] When the transparent conductive layer is an ITO layer, the crystallinity of the transparent conductive layer is preferably 80% or higher, more preferably 90% or higher, even more preferably 95% or higher, particularly preferably 98% or higher, and most preferably 99% or higher. Achieving a crystallinity above these levels can increase conductivity.

[0107] The transparent conductive layer can be provided by known methods according to each transparent conductive layer. For example, in the case of the ITO layer, sputtering is preferred, and specifically, it is preferable to provide a zinc oxide-based composite oxide (or composite oxide) as ITO using the method described for the gas barrier layer.

[0108] When a transparent conductive layer is provided on the gas barrier layer surface of a gas barrier film, it may be provided directly on the gas barrier layer or via an intermediate layer. The intermediate layer may be the functional layer mentioned above, but more preferred intermediate layers include resin layers such as hard coats, and inorganic layers such as silicon oxide and aluminum oxide. The thickness of the intermediate layer is preferably 1 to 10 μm if it is a resin layer, and preferably 10 to 100 nm if it is an inorganic layer.

[0109] When the transparent conductive layer is provided on the transparent plastic film side of the gas barrier film, the transparent conductive layer may be provided directly on the transparent plastic film or via an easy-adhesion layer or an easy-slip layer. When the transparent conductive layer is provided by coating, it is preferable that it be provided on an easy-adhesion layer or an easy-slip layer. On the other hand, when the transparent conductive layer is provided by a dry process such as sputtering, it is preferable that it be provided without directly using an easy-adhesion layer or an easy-slip layer. Furthermore, the transparent conductive layer may be provided on a functional layer of the transparent plastic film.

[0110] The light transmittance of the gas barrier film with a laminated transparent conductive layer is preferably 75% or more, more preferably 78% or more, even more preferably 80% or more, and particularly preferably 82% or more. The light transmittance is preferably 100% or less, more preferably 95% or less, even more preferably 90% or less, and particularly preferably 88% or less. By setting the light transmittance within the above range, when the gas barrier film with a laminated transparent conductive layer is used in a solar cell, the power generation efficiency can be increased, and when used in an image display device, a bright and clear image can be produced.

[0111] When providing a transparent conductive layer on a gas barrier film, the steps of providing the barrier layer and providing the transparent conductive layer on the film substrate may be performed separately or continuously. The separate method involves providing the gas barrier layer on the substrate, winding the film, and then unwinding the wound gas barrier film to provide the transparent conductive layer. The continuous method involves providing the gas barrier layer on the substrate and then providing the transparent conductive layer without winding the film. It is preferable to perform both the gas barrier layer and the transparent conductive layer using the same method, such as sputtering, as this makes it easier to adopt the continuous method. In this case, the wound film substrate may be placed in a vacuum layer, and the gas barrier layer and the transparent conductive layer may be provided using a sputtering apparatus having a center roll for laminating the gas barrier layer and a center roll for laminating the transparent conductive layer in the same vacuum layer, or the gas barrier layer and the transparent conductive layer may be provided using a sputtering apparatus having one center roll and multiple targets.

[0112] The transparent conductive layer may be a simple single-surface film (solid film), or it may be a film with a circuit pattern depending on the application. The circuit pattern can be appropriately designed for each application. In the case of the ITO layer, there are no particular limitations on how the circuit pattern is formed, and examples include wet etching, dry etching, laser etching, and the lift-off method. For wet etching, for example, etching solutions containing hydrofluoric acid, nitric acid, hydrochloric acid, etc. are used. In dry etching, for example, plasma is used to form the circuit pattern. ４ , O ２Examples include reactive ion etching (RIE) and deep reactive ion etching (DRIE), which involve reacting gases. Wet etching and dry etching are preferably performed in combination with photolithography techniques using resists.

[0113] The gas barrier film of the present invention is suitable for use in various electronic devices due to its high barrier properties, lightweight nature, low haze, and excellent transparency. For example, it is suitable as a barrier film for image display devices and solar cells, and is ideal for these applications not only because of its high barrier properties and lightweight nature, but also because of its low haze and excellent transparency. Examples of image display devices include organic EL image display devices, quantum dot image display devices, and micro-LED image display devices. These image display devices are susceptible to degradation of light-emitting elements due to moisture, etc., but the degradation of the light-emitting elements can be suppressed by using the gas barrier film of the present invention. In these image display devices, the gas barrier film may be used alone, but by using a transparent conductive layer laminated gas barrier film, a thin image display cell can be created without using a separate gas barrier film when used as a transparent conductive film substrate for a cell that controls image display. Furthermore, it is suitable not only when the image display cell is a quantum dot, but also when a quantum dot light source is used as a backlight for a liquid crystal display device. In addition, it is thin and has bending resistance, making it suitable for use in foldable image display devices.

[0114] While not particularly limited to solar cells, the gas barrier film of the present invention is suitably used in organic solar cells and perovskite solar cells. These solar cells are susceptible to degradation due to moisture and other factors in the organic semiconductor layer and perovskite layer, but by using the gas barrier film of the present invention, degradation of the light-emitting element can be suppressed, and stable power generation efficiency can be maintained for a long period of time. In particular, by using a transparent conductive layer laminated gas barrier film, when used as a transparent conductive film substrate for solar cells, it is possible to create lighter and thinner solar cells without using a separate gas barrier film. Perovskite solar cells, in particular, are excellent in terms of thinness, lightness, and flexibility, and the gas barrier film of the present invention is suitably used to make them thinner and lighter. Therefore, even when installed on window glass, roofs (skylights), etc., the burden on the structure is small, which is advantageous in terms of construction costs. Furthermore, by taking advantage of its low haze and high transparency characteristics, it is possible to achieve high power generation efficiency, and it also has the advantage of improving the light transmittance of the solar cell, making it easier to ensure light enter the room, and providing a clearer view of the outside scenery.

[0115] The following describes a perovskite solar cell as an example using the gas barrier film of the present invention, but the present invention is not limited to the following description. The layer configuration of the cell portion of a typical perovskite solar cell is: - Substrate / transparent conductive layer / electron transport layer / perovskite layer / hole transport layer / electrode layer / substrate or - Substrate / transparent conductive layer / hole transport layer / perovskite layer / electron transport layer / electrode layer / substrate. Perovskite solar cell Such a cell is sealed between gas barrier substrates using a encapsulant. The gas barrier film of the present invention is used on at least one of the gas barrier substrates. Furthermore, both gas barrier substrates may be the gas barrier film of the present invention. Also, by using the transparent conductive layer laminated gas barrier film of the present invention in the substrate / transparent conductive layer portion, a thin perovskite solar cell can be made without using a separate gas barrier film on the substrate / transparent conductive layer side. Furthermore, when the transparent conductive layer laminated gas barrier film of the present invention is used in the substrate / transparent conductive layer portion, it is also a preferred embodiment to use the gas barrier film of the present invention as the gas barrier film on the electrode layer / substrate side.

[0116] Let's briefly explain each component. The electron transport layer plays the role of efficiently collecting electrons generated in the perovskite layer and sending them to the external circuit (electrodes). Generally, n-type semiconductor materials such as titanium oxide, tin oxide, and zinc oxide can be used. In addition, barium titanate and zirconium oxide can be used, but are not limited to these, and various known materials can be used.

[0117] The perovskite layer absorbs sunlight and converts that energy into electricity. Generally, halide perovskites (e.g., CH4) are used. ３ NH ３ PbI ３ ya HC (NH ２ ) ２ PbI ３ ) and the like can be used. Furthermore, from the viewpoint of improving durability, systems with multiple components mixed together, such as cations (cesium, etc.) or halogens (bromine, etc.), or systems using tin instead of lead can be used, but the material is not limited to these, and various known materials can be used.

[0118] The hole transport layer plays the role of collecting holes (positive charge carriers) generated in the perovskite layer and sending them to the external circuit (electrode). Generally, spiromethyldiphenylamine or PEDOT:PSS (poly(3,4-ethylenedioxythiophene)) can be used, but the material is not limited to these, and various known materials can be used.

[0119] The electrode layer in the substrate / electrode layer portion plays the role of passing electrons or holes to the external circuit. It may be a metal layer such as Au, Ag, Cu, Al, Ni, Ti, Mo, or alloys thereof, or a transparent conductive layer may be provided on the substrate. The transparent conductive layer is the same as that described in the previous section on transparent conductive layers. The substrate is not particularly limited, but a resin film is preferred in terms of taking advantage of the flexibility of the perovskite solar cell. The material of the resin film is the same as that exemplified as the film substrate. This disclosure is not limited to these, and various known materials can be used. Furthermore, the transparent conductive layer laminated gas barrier film of the present invention may be used as the substrate / electrode layer.

[0120] The encapsulant adheres the cell to the gas barrier film, sealing it within the gas barrier film. Suitable encapsulants include, but are not limited to, polystyrene, polyvinyl chloride, polyvinyl butyral, polyisobutylene, polyimide, acrylic resin, polyurethane, ABS resin, epoxy resin, ethylene-vinyl acetate copolymer, ethylene methyl acrylate copolymer, ethylene-methyl methacrylate copolymer, polyethylene, modified polyethylene, polypropylene, modified polypropylene, polyoxymethylene, polyester, polyamide, and silicone; various known materials can be used.

[0121] Figure 1 illustrates a preferred example of a perovskite solar cell 10 when the transparent conductive layer laminated gas barrier film of the present invention is used in the substrate / transparent conductive layer portion. The transparent conductive layer laminated gas barrier film 11, which serves as the substrate for the perovskite solar cell 10, has a composite oxide film 112 on a film substrate 111, and a transparent conductive layer 113 of ITO on top of the composite oxide film 112. Circuit patterns are formed on the transparent conductive layer 113 by etching or other means as needed. Perovskite power generation elements 12 are provided on the transparent conductive layer 113. The perovskite power generation elements 12 are laminated in the order of electron transport layer / perovskite layer / hole transport layer, or hole transport layer / perovskite layer / electron transport layer. Electrodes 13 are further provided on the perovskite power generation elements 12, forming a perovskite solar cell. The perovskite solar cell portion is further sealed between the transparent conductive layer laminated gas barrier film 11 and the gas barrier film 15 using a sealing resin 14. Although not shown in the diagram, the transparent conductive layer and electrodes are connected to conductive wiring, and the generated current is extracted to the outside.

[0122] This application claims the benefit of priority under Japanese Application No. 2025-055377, filed on 28 March 2025. The entire specification of Japanese Application No. 2025-055377 is incorporated herein by reference.

[0123] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The evaluation methods used in each example and comparative example are as follows.

[0124] [Outgassing Amount] Sample Preparation A gas barrier film (approximately 10 cm x 20 cm) was prepared and stored in a desiccator containing silica gel at 23°C for one day. If there was a functional layer (back coat layer, etc.) on the opposite side of the barrier layer, to prevent contamination of outgassing from the functional layer, the center of the film was rubbed with #800 waterproof sandpaper to remove the functional layer, the powder was washed off with deionized water, the moisture was wiped off, and the film was stored in the desiccator in the same manner. Whether or not the functional layer had been removed was confirmed by the ATR-IR method. The film was removed from the desiccator, and a film piece approximately 3 mm wide x 100 mm long was cut from the center. Next, in order to efficiently extract outgassing components from inside the film substrate, a process was performed to intentionally destroy (crack) the gas barrier layer. Specifically, the film piece was placed lengthwise on a thin stainless steel rod approximately 0.5 mm in diameter (the bent part became the widthwise), and the film was moved back and forth three times by holding both ends of the film. The same procedure was performed on the opposite side (substrate side). Subsequently, one piece was cut from near the center of the film along its length, with a mass of approximately 10 mg, and this was used as the sample for measurement and weighed.

[0125] The film of the sample used for measurement was placed in a glass sample tube, and outgassing was qualitatively and quantitatively determined by thermal desorption-GCMS analysis (TD-GCMS). Toluene was used as a standard substance for quantification, and the value was determined as a toluene equivalent. The start point was defined as the point when the cooling of the trap section was stopped and the temperature was raised to the desorption temperature, and the total amount of components detected during the retention time (10 minutes to 35 minutes) was defined as the outgassing amount. Outgassing amount (ppm) = Mass of outgassing (μg) / Mass of sample (g) Thermal desorption analysis conditions TD instrument: Shimadzu TD-20 Sampling gas: Helium Sample tube: Glass tube (empty tube) P / N 223-57119 Sample heating temperature: 200°C Sample heating time: 60 minutes Desorption flow rate: 50 mL / min Cold trap tube: TenaxTA Trap cooling temperature: -20°C Trap desorption temperature: 280°C IF heating temperature: 230°C Valve temperature: 230°C Line temperature: 230°C

[0126] GCMS Analysis Conditions GCMS instrument: Shimadzu GCMS-QP2010Ultra Carrier gas: Helium Column: Rxi-1ms (length 60m, inner diameter 0.32mm, film thickness 0.25μm) Control mode: Linear velocity Column linear velocity: 35cm / sec Injection mode: Split Split ratio: 30.0 Purge flow rate: 3.0mL / min Column oven temperature: 50℃ (hold for 2min) - 15℃ / min heating - 320℃ (hold for 15min) Ion source temperature: 230℃ Interface temperature: 250℃ Measurement mode: Scan Scan mass range: m / z 35-550 Measurement method of standard toluene Toluene was diluted with methanol and injected into a TD sample tube (TenaxTA (130mg), P / N 223-57102-91). The TD sample heating temperature was changed to 270°C and the sample heating time to 10 min, while all other conditions remained the same as described above.

[0127] [Amount of embedded foreign matter] Using an optical microscope (Nikon H550L), with a 20x objective lens, the surface of the film (composite oxide film portion) was focused, and a 6 mm x 7 mm area of ​​the target sample was observed. The number of embedded foreign matter was counted and the amount per unit area (pieces / mm²) was determined.２ The number of foreign objects was calculated. Measurements were taken at any two locations and the calculation was performed using the following formula: Amount of embedded foreign objects = Total number of foreign objects at the two locations / 84 mm ２ Regarding the method for determining whether or not a sample is an embedded foreign object, any object that cannot be removed by lightly rubbing the sample surface with a cotton swab was considered an embedded foreign object. In addition, foreign objects located near the surface inside the film that could cause surface irregularities and reduce barrier properties were also counted as embedded foreign objects.

[0128] [Surface Roughness] The arithmetic mean height SRa and maximum peak height SRp are as defined in ISO 25178. Using a 3D surface shape measuring device, BartScan (manufactured by Ryoka Systems, R5500H-M100), roughness measurements were performed at five locations, and the arithmetic mean height SRa and maximum peak height SRp were determined at each location. The average values ​​of the arithmetic mean height SRa and maximum peak height SRp obtained at the five locations were calculated and used as the average arithmetic mean height and average maximum peak height. The measurement conditions were as follows: Measurement mode: wave mode Measurement wavelength: 560 nm Objective lens: 50x The five measurement points were selected by first choosing an arbitrary point A as the center, and then selecting one point each 1 cm above and below A in the longitudinal direction (MD) of the film, and one point each 1 cm to the left and right in the width direction (TD) of the film, for a total of five points. The arithmetic mean height SRa was rounded to one decimal place by rounding the second decimal place in nm units, and the maximum peak height SRp was rounded to an integer by rounding the first decimal place in nm units. Let X be the arithmetic mean height SRa of the inorganic oxide thin film and the transparent conductive layer (the side where the composite oxide film is planned to be laminated), and Y be the arithmetic mean height SRa of the side of the transparent plastic film substrate opposite to the inorganic oxide thin film side (the opposite side). Let Z1 be the average maximum peak height SRp of the inorganic oxide thin film and the transparent conductive layer, and Z2 be the average maximum peak height SRp of the side of the transparent plastic film substrate opposite to the inorganic oxide thin film side.

[0129] [Oxide film composition and conductive layer composition] The sample was pre-treated to prepare a measurement solution, and the elemental concentrations in the resulting measurement solution were measured using a high-frequency inductively coupled plasma (ICP) emission spectrometer to calculate the elemental content in the sample. As part of the pre-treatment, the sample was cut (approximately 15 cm) ２The sample was placed in a quartz Erlenmeyer flask, 20 ml of 6 mol / l hydrochloric acid was added, and the flask was sealed with a film to prevent acid evaporation. It was left at room temperature for 9 days, occasionally agitated, to dissolve the transparent conductive layer. The remaining film was removed, and the hydrochloric acid in which the transparent conductive layer had dissolved was used as the measurement solution. The elements in the solution were determined by the calibration curve method using an ICP emission spectrometer (Ametek, SPECTRO BLUE® TI). The measurement wavelengths for each element were selected to be interference-free and highly sensitive. Standard solutions were obtained by diluting commercially available standard solutions. The composition of the oxide film was calculated by calculating the mass of each oxide from the masses of the detected elements zinc, silicon, aluminum, boron, gallium, indium, thallium, scandium, and yttrium, and then calculating the composition ratio (mass ratio) of the oxides. The composition ratio of the oxides was ZnO for zinc oxide and SiO for silicon oxide. ２ Aluminum oxide and metal oxide A are Al ２ O ３ , B ２ O ３ Ga ２ O ３ In ２ O ３ , Tl ２ O ３ , Sc ２ O3, Y ２ O ３ The values ​​are calculated as follows, with the total amount of these being taken as 100% by mass. Furthermore, if necessary, the composition ratio of each component may be expressed as atomic percent based on the atomic ratio of each detected element. The composition of the transparent conductive layer was calculated by determining the mass of each oxide from the obtained masses of indium and tin, and then calculating the mass ratio of the oxides. The oxide composition ratio is as follows: Indium oxide is In ２ O ３ Tin oxide is SnO ２ This value is calculated based on the total amount of indium oxide and tin oxide being 100% by mass.

[0130] [Composite Oxide Film Thickness and Conductive Layer Thickness] Using a focused ion beam (FIB) processing apparatus, ultrathin sections in a roughly rectangular parallelepiped shape were processed by excavating from the surface of a film laminated with transparent conductive thin films to a depth in the film thickness direction until reaching the film substrate. In the ultrathin section, the surface with the largest area of ​​the roughly rectangular parallelepiped is the cross-section in the film thickness direction. When viewed from this surface with the largest area, at least a portion of the film substrate and the entire thickness of the composite oxide film, and if a transparent conductive thin film is present, the entire thickness of the transparent conductive thin film, are observed. The thickness of the ultrathin section (thickness as seen from the surface with the largest area) was set to 100 nm. Next, these prepared ultrathin sections were observed using a JEOL JEM2100 transmission electron microscope from the direction of the surface with the largest area, under conditions of an acceleration voltage of 200 kV, and photographs were taken at bright-field magnification of 10,000x. The film thickness of each layer was calculated from the obtained images.

[0131] [Surface resistance of composite oxide film] Measurements were taken using a Nitto Seiko Analytech Highresta (registered trademark) UX MCP-HT800 at a voltage of 1000V. The measurement taken after 1 minute was used. In Table 3, the surface resistance was 1 × 10⁻⁶. １３ A level of Ω / sq. or higher is marked with "○", and a surface resistance of 1 × 10⁻⁶ is indicated. １３ Levels below Ω / sq. were marked with "×" and noted accordingly.

[0132] [Color difference b] The transmitted color difference b of the transparent conductive film was measured using a Ze6000 manufactured by Nippon Denshoku Industries Co., Ltd., in accordance with JIS Z 8722:2009.

[0133] [Total Light Transmittance] In accordance with JIS-K7361-1:1997, the total light transmittance was measured using an NDH-2000 manufactured by Nippon Denshoku Industries Co., Ltd.

[0134] [Particle Size] Three observation sites were randomly selected from each cross-section of the film substrate, and the particles at each observation site were observed using a scanning electron microscope (KEYENCE VE-8800). Fifty particles were randomly extracted from each observation site, and their particle sizes were observed. Next, the observed 50 particles were divided into 0.010 μm intervals based on their particle size (equivalent circle diameter), and the total number of particles in each interval was determined. A histogram was created with the number of particles on the vertical axis and the particle size in 0.010 μm intervals on the horizontal axis. For particles whose particle size falls within 30% of the absolute value of the center value of the particle size interval where the maximum value of the normal distribution peak in the histogram is obtained, the average number of observed particle sizes was taken as the average particle size. For example, if there are two normal distribution peaks in the histogram, it indicates that two types of particles have been added, and the average particle sizes of the two types were calculated using the same method as described above. The average particle diameters at three locations in the cured resin layer were further averaged, and the average particle diameter of the cured resin layer and the average particle diameters at three locations in the functional layer were further averaged to obtain the average particle diameter of the functional layer. Note that the particle sizes added to the coating solution described in the following examples are representative values ​​from the catalog, but the above method was used to confirm that the particle sizes were the same.

[0135] [Surface Protection Film Peel Strength] The peel strength was measured according to the following method in accordance with JIS-Z-0237 (2000) Test Method for Adhesive Tapes and Adhesive Sheets. An acrylic plate (manufactured by Mitsubishi Rayon Co., Ltd.: Acrylite®, 3 mm thick) measuring 50 mm x 150 mm was prepared as the adherend. As a test piece for the surface protection film, a test piece measuring 150 mm in the winding direction of the film and 25 mm in the direction perpendicular to it was cut out, and the adherend and the test piece were pressed together by moving a 2000 g rubber roll (with a spring hardness of 80 Hs on the roller surface, covered with a 6 mm thick rubber layer, 45 mm wide, and a diameter (including the rubber layer) of 95 mm) back and forth at a speed of 5 mm / second. After pressing, the samples were left for 30 minutes at a temperature of 23°C and a relative humidity of 65%. Then, using a Shimadzu "Autograph" (registered trademark) (AGS-J) device, the maximum resistance at which the samples were peeled at a speed of 300 mm / min at a 180-degree angle was defined as the adhesive strength [mN / 25mm]. 180-degree peeling means maintaining a 180-degree peeling angle between the acrylic plate and the film when measuring the resistance value during peeling. For measurement, a polyester sheet with a thickness of 190 μm and dimensions of 25 mm x 170 mm was prepared as a gripping area for the measurement sample. This sheet was attached to the edge of the surface protection film side of the measurement sample (where the surface protection film and acrylic plate were pressed together) with cellophane tape, with a 15 mm adhesive margin, to serve as the gripping area for measurement. The above measurement was performed three times, and the average value was defined as the peeling force.

[0136] [Dimensional change rate at 120°C] In accordance with JIS C 2151, the dimensions A before heat treatment and the dimensions B after being left in a constant temperature bath maintained at 120±3°C for 30 minutes were measured using an image measuring instrument (Mitutoyo Corporation: QS-L1020Z / AF), and the dimensional change rate H was calculated using the following formula: H (%) = (A - B) / A × 100. Sampling (20 mm × 150 mm) was performed in the flow direction and width direction of the transparent conductive film, and the dimensional change rate HMD at 120°C for 30 minutes in the flow direction of the transparent conductive film and the dimensional change rate HTD at 120°C for 30 minutes in the width direction of the transparent conductive film were measured.

[0137] [150°C shrinkage rate] The 150°C heat shrinkage rate of the film substrate was measured in the same manner as the 120°C dimensional change rate described above, except that the temperature of the constant temperature bath was set to 150°C ± 3°C.

[0138] [Water Vapor Permeability] Water vapor was used as the test gas and measured under an atmosphere of 85°C and 85% RH using a differential pressure type gas permeability measuring instrument (GTR-3000XASK, manufactured by GTR Tech Co., Ltd.). The sample size was 50 cm². ２ To prevent cracking of the barrier layer, an 80 mm diameter polyfluorocarbon filter was placed on the sample stage, and the sample was set on the filter with the barrier layer facing downwards. Each measurement took 30 minutes, and the same sample was measured every two hours, repeating the measurement until the value stabilized. During the repeated measurements, the atmosphere was maintained at 85°C and 85% RH. The coefficient of variation was calculated using the data from the most recent five consecutive measurements, and the value was considered stable when the coefficient of variation fell below 5%. The water vapor transmission rate was based on the data from the last measurement.

[0139] [Helium Gas Permeability] Permeability was measured using a K-315N-01 gas permeability measuring device manufactured by Tsukuba Rika Seiki Co., Ltd. The measurement area for permeability was approximately 7854 mm² in a circle with a diameter of 100 mm. ２ The high-pressure side has a pressure of 1013 hPa at 1 atmosphere. The high-pressure side has a volume of approximately 1000 ml, and the low-pressure side has a volume of 24.42 ml. The high-pressure side pressure was measured using a diaphragm-type pressure gauge from MKS's Balatron 722A. The low-pressure side pressure was measured using a diaphragm-type pressure gauge from MKS's Balatron 615A. The gas used was ultra-high-purity helium gas (99.9998%). The measurement temperature was 23°C. After setting up the apparatus and placing the sample in the measurement cell with the inorganic thin film layer side facing the high-pressure side, both the high-pressure and low-pressure cells were evacuated using a turbomolecular pump. When the vacuum of the low-pressure cell was stopped without gas being introduced into the high-pressure cell, the pressure rise rate was 5 × 10⁻⁶. ―４The system was thoroughly evacuated until the pressure was below Pa / sec. Then, the valves connecting to the high-pressure and low-pressure cells were closed to disconnect them from the vacuum pump, and the background pressure increase rate was measured by measuring the pressure rise rate in the low-pressure cell. Next, helium gas was introduced into the high-pressure cell, and the amount of gas permeating through the sample was measured. The pressure on the low-pressure side was measured at 1-second intervals, and the pressure increase rate per minute was calculated to confirm the change. After confirming that the pressure increase rate per minute was nearly constant, measurements were continued for 15 minutes to determine the pressure increase rate over 15 minutes. As explained in Figure 3, 210 represents the pressure in the low-pressure cell, and from 201 onwards, when helium gas is introduced into the high-pressure cell, the pressure in the low-pressure cell increases. Initially, the amount of permeating gas gradually increases (section 205), and then becomes nearly constant (section 206). After confirming that it has become nearly constant, measurements were continued for 15 minutes (section 207), and the pressure increase rate in section 207 was determined. Note that it can be determined that it has become nearly constant by, for example, drawing an auxiliary line 220. Alternatively, after initiating the introduction of helium gas into the high-pressure cell, the pressure measurement of the low-pressure cell may be continued, and the point in time 202 when the pressure increase in the low-pressure cell became constant may be determined from the resulting graph, as shown in Figure 3. The pressure increase rate obtained by subtracting the previously determined background pressure increase rate from the calculated pressure increase rate is considered to be due to the gas that permeated from the sample. The amount of permeated gas was calculated from the cell volume and measured temperature, and the gas permeability was calculated from the pressure difference between the high-pressure and low-pressure sides and the measured area.

[0140] [Conductive layer surface resistance] Measured using the four-terminal method in accordance with JIS-K7194:1994. The measuring instrument used was a Lotesta AX MCP-T370 manufactured by Mitsubishi Chemical Analytech Co., Ltd.

[0141] [Conductive layer thickness] The measurement was performed in the same manner as for oxide thickness, except that a film sample piece with a laminated transparent conductive thin film layer was used.

[0142] [Intrinsic viscosity IV of polyester] Approximately 3 g of the sample was freeze-dried and dried at 140°C for 15 minutes. Then, 0.20 g was weighed out and dissolved completely in 20 ml of a mixed solvent of 1,1,2,2-tetrachloroethane and p-chlorophenol in a 1:3 (mass ratio) mixture, stirred at 100°C for 60 minutes. After cooling to room temperature, the sample was passed through a glass filter. The settling time of the sample and solvent was measured using an Ubbelohde viscometer (manufactured by Rigosha Co., Ltd.) temperature-controlled to 30°C, and the intrinsic viscosity [η] was determined by the following formula. [η] = (-1 + √(1 + 4K'ηSp)) / 2K'C ηSp = (τ - τ0)τ0 Where, [η]: Intrinsic viscosity (dl / g) ηSp: Specific viscosity (-) K': Huggins constant (= 0.33) C: Concentration (= 1 g / dl) τ: Sample settling time (sec) τ0: Solvent settling time (sec)

[0143] [Coating Layer Thickness] The film substrate was embedded in epoxy resin, and the cross-section cut out with a microtome was observed with a scanning electron microscope to determine the thickness. The magnification was adjusted as appropriate according to the thickness.

[0144] [Height difference of the roll end face] As shown in Figure 4, one side of the triangular ruler 3 that forms a right angle is placed against the core 2 of the roll, and the other side of the triangular ruler 3 that forms a right angle is placed against the most protruding part of the roll end face 1. The distance 4 between the most recessed part of the roll end face 1 and the ruler was measured with calipers. Note that a square ruler (L-shaped ruler) or other ruler with a right angle can be used instead of a triangular ruler.

[0145] [Preparation of Film Substrates] PEN Films 1-3 As the resin, polyethylene-2,6-naphthalate (obtained using manganese acetate tetrahydrate as a transesterification catalyst and antimony trioxide as a polymerization catalyst) with an intrinsic viscosity IV of 0.60 dl / g (measured at 35°C with orthochlorophenol solution) was dried in a 170°C dryer for 6 hours and then fed into an extruder. The above resin was melt-kneaded at a melting temperature of 300°C and extruded from a die slit at 300°C, and then cooled and solidified on a casting drum set to a surface temperature of 25°C to produce an unstretched film. The obtained unstretched film was guided to a group of rolls heated to 140°C and stretched 3.3 times in the longitudinal direction. On one side of the longitudinally stretched film, an easy-adhesion layer coating liquid 1, having the following solid content, was applied as an easy-adhesion adhesive to a dry thickness of 0.1 μm after stretching. The film with the coated layer was guided into a tenter while both ends were held with clips, and stretched 3.5 times laterally in an atmosphere heated to 135°C. In the tenter, heat setting and 1% relaxation treatment were performed at 230°C, and the film was cooled to obtain a biaxially oriented film with a thickness of 100 μm. Furthermore, the obtained film was annealed offline at 180°C for 3 minutes. The uncoated layer side was used as the surface for composite oxide film lamination. That is, in PEN films 1 to 3, there is no undercoat layer or backcoat layer before barrier layer formation, and the side with the easy-adhesion layer becomes the opposite side of the barrier layer. PEN films 2 and 3 were obtained in the same manner except that the thickness was changed by changing the extrusion rate of the extruder. The film manufacturing and annealing treatment were carried out in a clean environment of ISO Class 7, and the annealed film was wound up in a clean environment of Class 6 with a surface-side protective film laminated to the side for composite oxide film lamination and a back-side protective film laminated to the opposite side. The film was then unwound, and with the protective films on both sides laminated together, it was slit to the required width from near the center in the width direction of the film and wound up. The slitting was performed in a Class 6 clean environment, and a suction device was installed near the slitting blade to suck up the chips that flew off during slitting.

[0146] Coating liquid 1 for easy-adhesion layer Composition・Polyester aqueous dispersion 82% by mass (Composition: NDC / IPA / Na-SIP / / EG / DEG=60 / 35 / 5 / / 90 / 10 ・Oxazoline group-containing acrylic aqueous dispersion 5% by mass (Epocros (registered trademark) WS-700 manufactured by Nippon Shokubai Co., Ltd.) ・Silicone acrylic composite fine particles 0.5% by mass (Soliostar (registered trademark) manufactured by Nippon Shokubai Co., Ltd., average particle diameter: 250 nm) ・Silica particles 2.5% by mass (Snowtex (registered trademark) manufactured by Nissan Chemical Corporation, average particle diameter: 50 nm) ・Polyoxyethylene lauryl ether 5% by mass (Naroacty (registered trademark) N-70 manufactured by Sanyo Chemical Industries, Ltd.) ・Carnauba wax 5% by mass

[0147] PEN films 4, 5 A curable coating liquid 1 mainly containing dipentaerythritol hexa(meth)acrylate and silica nanoparticles (trade name Z7501 (manufactured by JSR Corporation) adjusted to a solid content concentration of 40% with MEK) was uniformly applied by a roll coater to one surface of an unslit film obtained in the same manner as PEN film 3 except that easy-adhesion layers were provided on both surfaces. Subsequently, after coating, drying treatment was performed at 70°C for 2 minutes, and then UV irradiation was performed using a high-pressure mercury lamp. The UV irradiation dose was 300 mJ / cm ２ and a flattening coating layer having the thickness shown in Table 1 was provided as an undercoat. Further, on the other surface, the following curable coating liquid 2 was used, and a hard coat layer was provided as a back coat layer in the same manner as the above flattening coating layer except that the thickness was adjusted as shown in Table 1. Note that no back-side protective film was laminated on PEN film 4. The flattening coating layer surface was used as the surface for laminating a composite oxide film. Each coating was performed in a class 7 clean environment. After coating, a protective film was laminated on the surface for laminating the composite oxide film, and the film was wound up, and then a slit film was obtained in the same manner as described above.

[0148] A curable coating solution 2, manufactured by JSR Corporation and trade name: Z7501, was used as the binder component. Acrylic fine particles with an average particle size of 80 nm and a refractive index of 1.49 were added in such a ratio that the solid content of the fine particles was 0.5 parts by mass per 100 parts by mass of solid content of the binder component. Methyl ethyl ketone (MEK) was added to this, and the solution was diluted to a solid content concentration of 37% by mass to obtain a coating solution for forming a backcoat layer (hardcoat layer).

[0149] PEN film 6 A biaxially oriented PEN film containing lubricant particles (Teonex® Q5100, manufactured by Toyobo Co., Ltd., 125 μm thick) was used. One side was designated for composite oxide film lamination. To remove foreign matter adhering to the film, both sides of the film were passed through an adhesive roll, and then protective films were laminated to both sides and the film was wound up to obtain a slit film in the same manner as described above. These processes were carried out in a Class 6 clean environment.

[0150] PEN Film 7 was manufactured in the same manner as PEN Film 1, except that it was in a Class 8 clean environment. After manufacturing, the film was wound without laminating the front and back protective films together, and then slit to the required width in a Class 7 environment. No suction was used during slitting.

[0151] Using COP film Zeonor film (registered trademark) ZF14 (manufactured by Nippon Zeon Co., Ltd., 100 μm), one side was designated as the surface for composite oxide film lamination, and protective films were laminated to both sides in the same manner as with PEN film 6. Further slitting was performed to obtain a slit film.

[0152] PET Film 1: After drying polyethylene terephthalate (IV = 0.62), it was fed into a twin-screw extruder and melt-kneaded at 285°C. The sheet extruded onto a cooling roll was roll-stretched 3.2 times in the length direction, and one side was coated with the following easy-adhesion coating liquid 2 to a film thickness of 0.1 μm after stretching. Then, it was roll-stretched 3.5 times in the width direction in a tenter to obtain a PET film with a thickness of 125 μm.

[0153] Two compositions of coating liquid for easy adhesion layer (Note: Mass % is the ratio of solids): • 42 parts by mass of polyester aqueous dispersion with the following copolymer composition (Copolymer composition (molar ratio) TPA / IPA / Na-SIP / EG / NPG = 48 / 47 / 5 / 50 / 50 (molar ratio)) • 34.5 parts by mass of polyurethane aqueous dispersion 18 parts by mass of polyurethane resin and crosslinking agent comprising aliphatic polycarbonate polyol manufactured in reference to paragraph

[0112] of WO19 / 058999 Block polyisocyanate crosslinking agent manufactured in reference to paragraph

[0114] of WO19 / 058999 5 parts by mass of small particle size silica sol with an average particle size of 40 nm 0.5 parts by mass of large particle size silica sol with an average particle size of 500 nm

[0154] A curable coating liquid 3 with the following composition was applied as an undercoat layer to the non-adhesion layer surface of the obtained PET film so that the film thickness after drying was 600 nm, and it was dried at 140°C for 15 seconds to form a planarized coating layer. The planarized coating layer surface was used as the surface for laminated composite oxide film. The film was manufactured and coated in the same clean environment as the PEN film 4, and after laminating protective films to both sides in the same manner, it was slit to obtain a slit film.

[0155] Curable coating solution 3 composition: Methyl ethyl ketone 49.45 parts by mass, Toluene 49.45 parts by mass, Melamine compound 1.00 part by mass (Full ether-type methylated melamine, 100% solids, manufactured by Sanwa Chemical Co., Ltd., trade name MW-30M, weight-average degree of polymerization 1.3), Acid catalyst 0.10 parts by mass (p-toluenesulfonic acid, manufactured by Hitachi Chemical Co., Ltd., trade name Dryer® 900, solids concentration adjusted)

[0156] PET Film 2 A high retardation PET film (Cosmoshine SRF® TA-044, manufactured by Toyobo Co., Ltd., 80 μm thick) was coated with the above-mentioned curable coating liquid 1 on one side, and a planar coating layer with a thickness of 8.0 μm was provided as an undercoat layer. The other side was uniformly coated with the following curable coating liquid 4 using a roll coater. After coating, a drying treatment was performed at 70°C for 2 minutes, and then UV irradiation was performed using a high-pressure mercury lamp. The UV irradiation dose was 300 mJ / cm². ２ The process was carried out, and a hard coat layer with a thickness of 8 μm was provided as a back coat layer. The smoothed coat layer surface was used as the surface for composite oxide film lamination. CosmoShine SRF (registered trademark) is manufactured in a clean environment, and each coat was applied in the same clean environment as PEN film 4. In the same manner, protective films were laminated to both sides, and slitting was performed to obtain slit films.

[0157] A curable coating solution 4, manufactured by JSR Corporation, product name: Z7501, was used as the binder component. Crosslinked acrylic resin particles with an average particle size of 0.8 μm (manufactured by Soken Chemical Co., Ltd., product name: MX-80H3wT) were added as organic particles in an amount of 0.7% by mass relative to 100% by mass of the solid content of the binder component. This was then diluted with methyl ethyl ketone (MEK) to a solid content concentration of 30% by mass.

[0158] Table 1 shows the properties of the obtained film substrates. The properties of the film substrates were measured after peeling off the protective film on the front and back sides. The following commercially available products were used for the front protective film. For the back protective film, a polyethylene film (thickness 65 μm) with an acrylic adhesive was used. HG5-50EX: Fujicopian Co., Ltd. FIXFILM-HG5-50EX KD26F: Sanei Kaken KD26F PAC-2-70: Sanei Kaken PAC-2-70 JA16F: Sanei Kaken JA16F

[0159]

[0160] (Examples 1-7, 10, Comparative Examples 1, 3, 4) A base film with the protective film obtained above laminated is placed in the sputtering apparatus shown in Figure 2, and 1.5 × 10－４ Vacuum was applied to Pa. Next, oxygen was introduced, followed by argon, to bring the total pressure to 0.6 Pa. The oxygen partial pressure was set to the values ​​shown in Table 2. The film was unwound in the vacuum layer, the protective film on the front side was peeled off, and then it was passed through the center roll 7 and wound on the opposite side. During this process, the film was run so that the non-film-deposited side of the film substrate (the side with the protective film still attached) was in contact with the center roll 7. For samples with a protective film on the back side, the film was deposited without peeling off the protective film on the back side. A zinc oxide-based composite oxide film was formed on the film substrate 6 on the center roll 7 by sputtering from the target 9 in the chimney 8. For the target 9, a zinc oxide-silicon oxide-aluminum oxide sintered target was used, or a sintered target containing metal oxide A (zinc oxide-silicon oxide-metal oxide A) instead of aluminum oxide was used. 3 W / cm ２ Power was applied at a power density of 0.5 W / cm², and a composite oxide film was deposited by DC magnetron sputtering. The composition of the composite oxide film was varied by changing the composition of the target. The film thickness was controlled by changing the speed at which the film passed over the target. The ratio of water pressure to argon in the deposition atmosphere during sputtering was measured using a gas analyzer (Inficon, Transspector® XPR3) and is shown in Table 2. As shown in Table 2, this water pressure ratio was adjusted by the presence or absence of a bombardment process, the presence or absence of a protective film on the back side, the difference in the unevenness of the film roll edge, and the temperature of the heating medium of the temperature controller that controls the temperature of the center roll in which the film is in contact. In the bombardment process, SUS (stainless steel) was used as the target at 0.5 W / cm². ２ RF sputtering was performed. The amount of gas introduced for RF sputtering was the same as the amount of gas introduced into the vacuum apparatus as described in the examples and comparative examples. The temperature of the heating medium was set to the value shown in Table 2, which is the temperature exactly in the middle of the maximum and minimum temperatures from the start to the end of film formation on the film roll.

[0161] (Comparative Example 2) Film formation was carried out in the same procedure as in Example 1, except that PEN film 7 was used as the film substrate. The easily adhesive layer side of the film substrate was positioned towards the center roll.

[0162] (Example 8) A composite oxide film was formed under the same conditions as in Example 1 and the like above, using PET film 1 as the film substrate. An ITO layer (containing 12% by mass of tin oxide) was provided as a transparent conductive layer on the composite oxide film surface of the obtained gas barrier film. Conditions for forming the ITO layer were as follows: the sputtering power supply had a power of 3 W / cm ２ , a pulse frequency of 100 kHz, and a pulse width of 2 μs, and the gas partial pressure was the same as the condition for forming the gas barrier film. Thereafter, the back-side protective film was peeled off, and a heat treatment was performed at 150°C for 60 minutes.

[0163] (Example 9) PEN film 1 was unwound in a class 6 clean environment, and after peeling off the surface protective film, it was wound up. The wound film roll was placed into a vacuum layer, and film formation was carried out by the same procedure as in Example 1, except that the surface protective film was not peeled off in the vacuum layer immediately before film formation.

[0164] (Example 10) A gas barrier film was produced in the same manner as in Example 1, except that gallium oxide was used as the metal oxide A in a sputtering target for forming a composite oxide film. Specifically, as shown in Table 2, ZnO: SiO ２ : Ga ２ O ３ system target was used.

[0165] Detailed film formation conditions for the composite oxide film are described in Table 2.

[0166]

[0167] Properties of the obtained gas barrier film and the conductive layer-laminated gas barrier film are shown in Table 3. The film properties were measured after peeling off the back-side protective film. Further, when a conductive layer is provided directly on the gas barrier layer, the surface roughness properties of the gas barrier layer and the surface roughness properties of the conductive layer are almost the same, so the values of SRa and SRp on the transparent conductive layer side were used as the SRa and SRp on the composite oxide film side in Example 8.

[0168]

[0169] Examples 1-4 and 10 are examples where PEN film was used as the film substrate. Outgassing was low, and although the gas barrier properties were affected by the amount of embedded foreign matter, they were all good. Example 5 is an example where COP film was used as the film substrate. Although the outgassing was slightly higher than that of the PEN film in Example 1, the amount of embedded foreign matter was low, and the gas barrier properties were good. In Example 6, perhaps due to the thickness of the coating layer, the outgassing was high, and the barrier properties were slightly inferior to those of Example 1, but not at a problematic level. In Example 7, the outgassing was slightly higher than that of Example 1 due to the effect of the coating layer, but the amount of embedded foreign matter was low, and the gas barrier properties were even better. Example 8 uses PET as the film substrate and has a transparent conductive layer laminated on top. Although the outgassing and surface roughness were slightly high, the gas barrier properties were good, and it showed excellent characteristics as a conductive layer laminated gas barrier film. In Example 9, the surface protective film was peeled off under clean conditions before the film was fed into the sputtering apparatus. The gas barrier properties were equivalent to those of Example 1, in which the surface protective film was peeled off within the sputtering apparatus. As shown in Example 10, even when gallium oxide was used instead of aluminum oxide, a gas barrier film with excellent surface smoothness, transparency, gas barrier properties, and outgassing characteristics was obtained.

[0170] Comparative Example 1 had a large amount of embedded foreign matter. It is thought that the peeling force of the surface protective film was too high, resulting in adhesive residue and thus a large amount of embedded foreign matter. In addition, the silicon oxide content of the composite oxide film was low. Due to these effects, the gas barrier properties were poor. Also, the color difference b was large due to the low oxygen partial pressure when the composite oxide film was formed. Comparative Example 2 was an example in which no protective film was used. The amount of embedded foreign matter was large, and the moisture pressure during the formation of the composite oxide film was high, and the pulse frequency of the sputtering power supply was high, so the gas barrier properties were considerably poor. Comparative Example 3 was an example in which a PET film with a coating layer was used as the film substrate. Due to the effects of a large amount of outgassing, a large 120°C dimensional change rate of MD, a thin composite oxide film thickness, and a low zinc oxide content in the composite oxide film, the gas barrier properties were poor. Furthermore, in Comparative Example 3, the SRa and SRp on the opposite side of the composite oxide film were large, which may lead to deterioration of the gas barrier properties when the back surface and the composite oxide film come into contact during post-processing. Also, if the composite oxide film is formed without applying a protective film to the back surface, the gas barrier properties may deteriorate due to contact between the back surface and the composite oxide film. Comparative Example 4 is an example in which a PEN film containing particles was used as the film substrate. It had high surface roughness and poor barrier properties. In addition, the transparency was poor due to the effect of the particles.

[0171] From the results above, the gas barrier films of the examples showed excellent gas barrier properties and were suitable for use as gas barrier films in various applications, particularly as gas barrier films for perovskite solar cells. Furthermore, as shown in Example 8, it was found that the conductive layer-laminated gas barrier film, obtained by laminating a transparent conductive layer onto the gas barrier film of the present invention, can be made thin without the need for a separate gas barrier film when used, for example, as a film substrate for perovskite solar cells.

[0172] The present invention provides a gas barrier film that has high barrier properties and, when used as a component of electronic devices requiring advanced gas barrier properties, such as solar cells and electroluminescent display devices, can maintain stable performance for a long period of time as an electronic device. Furthermore, by laminating a transparent conductive layer onto the gas barrier film, it is possible to make the gas barrier film function as a transparent conductive film in electronic devices, resulting in a thin device that is advantageous in terms of cost, productivity, and resource conservation. Moreover, it is possible to provide thin electronic devices, particularly perovskite solar cells, using these gas barrier films.

[0173] 1 Film roll 2 Core 3 Triangle ruler 4 Measurement location for height difference of roll end face 6 Film 7 Center roll 8 Chimney 9 Target 10 Perovskite solar cell 11 Transparent conductive layer laminated gas barrier film 111 Film substrate 112 Gas barrier layer 113 Transparent conductive layer 12 Perovskite power generation element 13 Electrode 14 Sealant 15 Gas barrier film 201 Point when helium gas is introduced into the high-pressure side cell 202 Point when the pressure rise in the low-pressure side cell becomes constant 210 Pressure of the low-pressure side cell 220 Auxiliary line

Claims

1. A gas barrier film comprising a zinc oxide-based composite oxide film laminated on at least one surface of a transparent plastic film substrate, wherein the average value of the arithmetic mean height SRa of the zinc oxide-based composite oxide film is 0.01 to 3 nm, and the foreign matter density of the zinc oxide-based composite oxide film, as determined by the following embedded foreign matter evaluation, is 0.40 particles / mm³. ２ A gas barrier film wherein the outgassing amount of the gas barrier film is 100 ppm or less.

2. The gas barrier film according to claim 1, wherein the zinc oxide-based composite oxide film comprises 45 to 97 atomic percent zinc oxide, 2.5 to 50 atomic percent silicon oxide, and 0.05 to 10 atomic percent aluminum oxide.

3. The gas barrier film according to claim 1, wherein the zinc oxide-based composite oxide film comprises 30 to 97 atomic percent of zinc oxide, 2.5 to 50 atomic percent of silicon oxide, and 0.05 to 35 atomic percent of metal oxide A, and the metal oxide A is an oxide containing one or more elements from among B, Ga, In, Tl, Sc, and Y.

4. The gas barrier film according to claim 1, wherein the thickness of the zinc oxide-based composite oxide film is 15 to 70 nm.

5. The gas barrier film according to claim 1, wherein a transparent conductive layer is laminated on at least one surface of the gas barrier film on which the zinc oxide-based composite oxide film is laminated.

6. The gas barrier film according to claim 1, wherein the color difference b is 2.0 or less, and the total light transmittance in the absence of a transparent conductive layer is 86% or more.

7. The gas barrier film according to claim 1, wherein a transparent conductive layer is laminated on at least one surface of the gas barrier film on which the zinc oxide-based composite oxide film is laminated, the color difference b is 2.0 or less, and the total light transmittance is 80% or more.

8. The gas barrier film according to claim 1, wherein the arithmetic mean height SRa of the opposite side of the zinc oxide-based composite oxide film is 5 nm or less.

9. The gas barrier film according to claim 1, wherein the maximum peak height SRp on the opposite side of the zinc oxide-based composite oxide film is 150 nm or less.

10. The gas barrier film according to claim 1, wherein the average maximum peak height SRp of the zinc oxide-based composite oxide film is 50 nm or less.

11. A perovskite solar cell comprising a gas barrier film as described in any one of claims 1 to 10.

12. A perovskite solar cell comprising a structure in which a hole transport layer, a perovskite layer, an electron transport layer, an electrode layer, and a substrate are laminated in that order on a transparent conductive layer of a gas barrier film according to any one of claims 1 to 10.

13. A perovskite solar cell comprising a structure in which an electron transport layer, a perovskite layer, a hole transport layer, an electrode layer, and a substrate are laminated in that order on a transparent conductive layer of a gas barrier film according to any one of claims 1 to 10.

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