Multilayer structure, method for producing multilayer structure, protective sheet for electronic device, and electronic device

Abstract

The present invention comprises a laminate (α) including a base material (X) and a layer (Y), and a laminate (β) including a base material (X) and a layer (Y'). The layer (Y) contains a reaction product (D) of an aluminum-atom-containing metal oxide (A) and an inorganic phosphorus compound (B). The layer (Y') contains at least one selected from the group consisting of metal oxides, metal nitrides, metal nitride oxides, metal carbide nitrides, and the reaction product (D). The laminate (α) and the laminate (β) are laminated with an adhesive layer (I) interposed therebetween. The total light transmittance measured in conformance with JIS K 7361-1:1997 is 87% or greater, and the moisture permeability measured in conformance with ISO 15106-5 is 2.0 × 10–3 g / m2⋅day or lower.

Description

Multilayer structure, method for producing multilayer structure, protective sheet for electronic device, and electronic device

[0001] The present invention relates to a multilayer structure, a method for producing a multilayer structure, a protective sheet for an electronic device, and an electronic device.

[0002] Electronic devices such as solar cells and electronic devices equipped with display devices require a light-transmitting protective member to protect their surfaces. Flexible solar cells and flexible displays have recently become popular among these electronic devices. Flexible electronic devices cannot use thick glass plates, so protective sheets are needed to replace thick glass plates.

[0003]

[0003] A protective sheet that can replace a glass plate needs to have excellent barrier properties, particularly excellent water vapor barrier properties. For example, Patent Document 1 describes such a protective sheet as a multilayer structure that includes a substrate (X) such as PET and a layer (Y) containing a reaction product of an aluminum-containing compound and phosphoric acid, in which the reaction product has an average particle size of 5 nm to 70 nm. The multilayer structure has excellent gas barrier properties and water vapor barrier properties, and can maintain its performance even after a dump heat test. Prior patent literature

[0004] International Publication No. 2016 / 103720

[0005] In recent years, protective sheets for electronic devices have been required to have very high water vapor barrier properties, but the above-mentioned conventional multilayer structures have sometimes lacked sufficient water vapor barrier properties. To meet the required high water vapor barrier performance, a method of laminating multiple films via a film adhesive layer having water vapor barrier properties has been considered. However, laminating multiple films via a film adhesive layer having water vapor barrier properties can result in reduced transparency, which can lead to reduced visibility when used in displays, etc., or reduced power generation efficiency when used in solar cells, etc. In addition, depending on the film lamination conditions, the protective sheet can become thick and its flexibility can be impaired, making it difficult to achieve a film that has high water vapor barrier properties while also having excellent transparency and flexibility. Meanwhile, in order to realize high-quality flexible electronic devices, there is a strong demand for members that are highly transparent, thin, and have high water vapor barrier properties.

[0006] The present invention has been made in light of the above circumstances, and an object of the present invention is to provide a multilayer structure that is highly excellent in water vapor barrier property and transparency and also excellent in flexibility, a method for producing a multilayer structure, a protective sheet for an electronic device, and an electronic device.

[0007] That is, the present invention provides: [1] a laminate (α) comprising a substrate (X) and a layer (Y), and a laminate (β) comprising the substrate (X) and a layer (Y′), wherein the layer (Y) comprises a reaction product (D) of a metal oxide (A) containing an aluminum atom and an inorganic phosphorus compound (B), and the layer (Y′) comprises at least one selected from the group consisting of a metal oxide, a metal nitride, a metal nitride oxide, a metal carbonitride, and the reaction product (D), the laminate (α) and the laminate (β) are laminated via an adhesive layer (I), and the laminate (α) and the laminate (β) have a total light transmittance of 87% or more as measured in accordance with JIS K 7361-1:1997 and a moisture permeability of 2.0 × 10 as measured in accordance with ISO 15106-5. －３ g / m ２[2] The multilayer structure according to [1], which comprises at least two or more laminates each comprising a substrate (X) and a layer (Y); [3] The multilayer structure according to [1] or [2], which has a haze value of 7% or less as measured in accordance with JIS K 7136:2000; [4] The multilayer structure according to any one of [1] to [3], in which at least one of the laminates has a structure in which a layer (Y) is disposed on both sides of a substrate (X); [5] The multilayer structure according to any one of [1] to [4], in which the thickness of one layer of the substrate (X) is 100 μm or less; [6] The multilayer structure according to any one of [1] to [5], in which the adhesive layer (I) contains at least one adhesive material selected from the group consisting of polyurethane, polyester, acrylic resin, epoxy resin, polyolefin elastomer, ethylene-vinyl acetate copolymer, polyvinyl butyral, and ionomer; [7] The multilayer structure according to any one of [1] to [6], which is laminated by dry lamination or vacuum lamination; [8] The multilayer structure according to any one of [1] to [7], wherein the adhesive layer (I) is a layer formed using a two-component adhesive; [9] In the infrared absorption spectrum of the layer (Y), －１ ~1400cm －１ The maximum absorption wave number in the region is 1080 cm －１ ~1130cm －１

[10] A multilayer structure according to any one of [1] to [9], which has a configuration in which a substrate (X) and a layer (Y) are laminated via an adhesive layer (AC);

[11] A multilayer structure according to any one of [1] to [9], which has a configuration in which a substrate (X) and a layer (Y) are laminated via an adhesive layer (AC);

[12] A multilayer structure comprising: a step (I) of applying a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent to a substrate (X), and removing the solvent to form a precursor layer of the layer (Y); a step (II) of heat-treating the precursor layer of the layer (Y) to form the layer (Y); and a step (III) of laminating at least two of the laminates obtained through the step (II) via the adhesive layer (I), wherein in the step (III), a two-component adhesive is applied to the surface of one of the laminates, and the solvent is removed to form an adhesive layer ( The present invention is achieved by providing a method for producing a multilayer structure according to [8], comprising a step (III-AI) of forming a laminate on the laminate via the adhesive layer (I), and a step (III-AII) of laminating the laminate via the adhesive layer (I) and then aging the laminate, wherein the drying temperature in step (III-AI) is 45°C or higher and 150°C or lower, and the aging conditions in step (III-AII) include condition 1, in which aging is performed at a temperature of 10°C or higher but lower than 35°C for 1 day or longer and condition 2, in which aging is performed at a temperature of 35°C or higher but 70°C for 1 day or longer and 30 days or shorter;

[12] a protective sheet for an electronic device comprising the multilayer structure according to any one of [1] to

[10] ;

[13] the protective sheet according to

[12] , which is a protective sheet for protecting the surface of a photoelectric conversion device, an information display device, or a lighting device;

[14] an electronic device having the protective sheet according to

[12] or

[13] .

[0008] According to the present invention, it is possible to provide a multilayer structure that has excellent water vapor barrier properties and transparency at a high level and also has excellent flexibility, a method for producing a multilayer structure, a protective sheet for an electronic device, and an electronic device.

[0009] FIG. 1 is a schematic diagram showing an electronic device of the present invention.

[0010] "Barrier properties" primarily refers to both oxygen barrier properties and water vapor barrier properties (low moisture permeability). "Gas barrier properties" primarily refers to oxygen barrier properties. In this specification, multiple layers may be the same or different. "Transparency" refers to a high total light transmittance measured in accordance with JIS K 7361-1:1997 and a low haze value measured in accordance with JIS K 7136:2000, and can be measured specifically by the method described in the Examples. Numerical ranges described using "to" include the numerical values ​​before and after "to" as the lower and upper limits. In other words, "a to b" means "a or more and b or less." The upper and lower limits of numerical ranges (content, physical properties, etc.) can be combined as appropriate.

[0011] The multilayer structure of the present invention comprises a laminate (α) containing a substrate (X) and a layer (Y), and a laminate (β) containing a substrate (X) and a layer (Y′), wherein the layer (Y) contains a reaction product (D) of a metal oxide (A) containing aluminum atoms and an inorganic phosphorus compound (B), and the layer (Y′) contains at least one selected from the group consisting of a metal oxide, a metal nitride, a metal nitride oxide, a metal carbonitride, and the reaction product (D), and the two or more laminates are laminated via an adhesive layer (I), and the multilayer structure has a total light transmittance of 87% or more as measured in accordance with JIS K 7361-1:1997 and a moisture permeability of 2.0×10 as measured in accordance with ISO 15106-5. －３ g / m ２ The multilayer structure of the present invention comprises a laminate (α) including a substrate (X) and a layer (Y), and a laminate (β) including a substrate (X) and a layer (Y′), wherein the layer (Y) contains a reaction product (D) of a metal oxide (A) containing an aluminum atom and an inorganic phosphorus compound (B), and thereby has a moisture permeability of 2.0 × 10 or less as measured in accordance with ISO 15106-5. －３ g / m ２As will be described later, by adjusting the conditions for laminating the two or more laminates via the adhesive layer (I), the total light transmittance tends to be easily adjusted to 87% or more. By providing such a configuration, it is possible to realize a multilayer structure that is excellent in transparency and flexibility while realizing a high level of water vapor barrier property, which was difficult to achieve with conventional barrier materials.

[0012] [Substrate (X)] The substrate (X) is not particularly limited, and various substrates can be used. The material of the substrate (X) is not particularly limited, and examples thereof include resins such as thermoplastic resins and thermosetting resins; metal oxides, etc. Among these, it is preferable that the substrate (X) contains a thermoplastic resin. The form of the substrate (X) is not particularly limited, and it is preferably a layer such as a film or sheet. The substrate (X) preferably contains a thermoplastic resin film or a thermoplastic resin film laminated with an inorganic vapor deposition layer (X'), more preferably a thermoplastic resin film, and even more preferably a thermoplastic resin film.

[0013] Examples of thermoplastic resins used in the substrate (X) include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate (PET), polyethylene-2,6-naphthalate, polybutylene terephthalate, and copolymers thereof; polyamide resins such as nylon-6, nylon-66, and nylon-12; hydroxyl group-containing polymers such as polyvinyl alcohol and ethylene-vinyl alcohol copolymers; polystyrene; poly(meth)acrylic acid esters; polyacrylonitrile; polyvinyl acetate; polycarbonate; polyarylate; regenerated cellulose; polyimide; polyetherimide; polysulfone; polyethersulfone; polyetheretherketone; ionomer resins, etc. The thermoplastic resin used in the substrate (X) is preferably at least one selected from the group consisting of polyethylene, polypropylene, polyethylene terephthalate, nylon-6, and nylon-66, with polyethylene terephthalate being more preferred.

[0014] When the thermoplastic resin film is used as the substrate (X), the substrate (X) may be a stretched film or a non-stretched film. Stretched films, particularly biaxially stretched films, are preferred because the resulting multilayer structure has excellent processability (printing, lamination, etc.). The biaxially stretched film may be a biaxially stretched film produced by any of simultaneous biaxial stretching, sequential biaxial stretching, and tubular stretching.

[0015] The thermoplastic resin film laminated with an inorganic vapor-deposited layer (X') used as the substrate (X) is usually a film having barrier properties against oxygen and water vapor, and is preferably a transparent film. The thermoplastic resin film used in the thermoplastic resin film laminated with an inorganic vapor-deposited layer (X') can be any of the thermoplastic resin films exemplified as the substrate (X) above. The inorganic vapor-deposited layer (X') can be formed by vapor deposition of an inorganic substance. Examples of inorganic substances include metals (e.g., aluminum), metal oxides (e.g., silicon oxide, aluminum oxide), metal nitrides (e.g., silicon nitride), metal nitride oxides (e.g., silicon oxynitride), and metal carbonitrides (e.g., silicon carbonitride). Among these, an inorganic vapor-deposited layer (X') formed of aluminum oxide, silicon oxide, magnesium oxide, or silicon nitride is preferred from the viewpoint of excellent transparency.

[0016] The method for forming the inorganic vapor deposition layer (X′) is not particularly limited, and examples thereof include physical vapor deposition methods such as vacuum deposition (e.g., resistance heating deposition, electron beam deposition, molecular beam epitaxy, etc.), sputtering, and ion plating; and chemical vapor deposition methods such as thermal chemical vapor deposition (e.g., catalytic chemical vapor deposition), photochemical vapor deposition, plasma chemical vapor deposition (e.g., capacitively coupled plasma, inductively coupled plasma, surface wave plasma, electron cyclotron resonance, dual magnetron, atomic layer deposition, etc.), and metalorganic chemical vapor deposition.

[0017] The thickness of the inorganic vapor deposition layer (X') varies depending on the types of components constituting the inorganic vapor deposition layer, but is preferably 0.002 μm to 0.5 μm, more preferably 0.005 μm to 0.2 μm, and even more preferably 0.01 μm to 0.1 μm. A thickness within this range may be selected so that the barrier properties and mechanical properties of the multilayer structure are improved. When the thickness of the inorganic vapor deposition layer (X') is 0.002 μm or more, the barrier properties of the inorganic vapor deposition layer (X') against oxygen and water vapor tend to be improved. Furthermore, when the thickness of the inorganic vapor deposition layer (X') is 0.5 μm or less, the barrier properties of the inorganic vapor deposition layer (X') tend to be maintained even after bending.

[0018] The thickness of each layer of the substrate (X) is preferably 5 μm or more and 200 μm or less, more preferably 7 μm or more and 100 μm or less, and even more preferably 10 μm or more and 80 μm or less. When the thickness of each layer (X) is 5 μm or more, the mechanical strength tends to be increased. When the thickness of each layer (X) is 200 μm or less, the flexibility of the resulting multilayer structure tends to be increased.

[0019] As the substrate (X), one type of substrate may be used alone, or two or more types of substrates may be used in combination. The substrates (X) contained in the multilayer structure may be the same or different.

[0020] [Layer (Y)] The layer (Y) contains a reaction product (D) of a metal oxide (A) and an inorganic phosphorus compound (BI). In the multilayer structure of the present invention, the layer (Y) functions as a barrier layer, and therefore the laminate including the substrate (X) and the layer (Y) tends to have good barrier properties.

[0021] [Metal Oxide (A) Containing Aluminum Atoms] The metal atom (M) constituting the metal oxide (A) is usually at least one metal atom selected from metal atoms belonging to Groups 2 to 14 of the periodic table, but it contains at least an aluminum atom. The metal atom (M) is preferably an aluminum atom alone, but may contain an aluminum atom and other metal atoms. Two or more metal oxides (A) may be used as a mixture. Examples of metal atoms other than aluminum atoms include metals from Group 2 of the periodic table, such as magnesium and calcium; metals from Group 12 of the periodic table, such as zinc; metals from Group 13 of the periodic table; metals from Group 14 of the periodic table, such as silicon; and transition metals, such as titanium and zirconium. Although silicon is sometimes classified as a metalloid, silicon is considered to be included in the metal category in this specification. The metal atom (M) that can be used in combination with aluminum is preferably at least one selected from the group consisting of titanium and zirconium, from the viewpoints of ease of handling and excellent gas barrier properties of the resulting multilayer structure.

[0022] The proportion of aluminum atoms in the metal atoms (M) is preferably 50 mol % or more, more preferably 70 mol % or more, and even more preferably 90 mol % or more, and even if it is 95 mol % or more, it may be composed essentially of aluminum atoms. Examples of the metal oxide (A) include metal oxides produced by methods such as liquid phase synthesis, vapor phase synthesis, and solid pulverization.

[0023] The metal oxide (A) may be a hydrolysis condensate of a compound (E) (hereinafter sometimes abbreviated as "compound (E)") containing a metal atom (M) to which a hydrolyzable characteristic group is bonded. Examples of the characteristic group include a halogen atom, NO ３Examples of the metal oxide (E) include an alkoxy group having 1 to 9 carbon atoms which may have a substituent, an aryloxy group having 6 to 9 carbon atoms which may have a substituent, an acyloxy group having 2 to 9 carbon atoms which may have a substituent, an alkenyloxy group having 3 to 9 carbon atoms which may have a substituent, a β-diketonato group having 5 to 15 carbon atoms which may have a substituent, and a diacylmethyl group having an acyl group having 1 to 9 carbon atoms which may have a substituent. The hydrolysis condensate of compound (E) can be considered to be substantially the metal oxide (A). Therefore, in this specification, the hydrolysis condensate of compound (E) may be referred to as "metal oxide (A)." That is, in this specification, "metal oxide (A)" can be read as "hydrolysis condensate of compound (E)," and "hydrolysis condensate of compound (E)" can also be read as "metal oxide (A)."

[0024] [Compound (E) containing a metal atom (M) having a hydrolyzable characteristic group bonded thereto] The compound (E) preferably contains a compound (Ea) containing an aluminum atom, which will be described later, because this facilitates control of the reaction with the inorganic phosphorus compound (BI) and results in excellent gas barrier properties of the resulting multilayer structure.

[0025] Examples of the compound (Ea) include aluminum chloride, aluminum nitrate, aluminum acetate, tris(2,4-pentanedionato)aluminum, trimethoxyaluminum, triethoxyaluminum, tri-n-propoxyaluminum, triisopropoxyaluminum, tri-n-butoxyaluminum, tri-sec-butoxyaluminum, tri-tert-butoxyaluminum, etc., and among these, triisopropoxyaluminum and tri-sec-butoxyaluminum are preferred. Two or more types of the compound (Ea) may be used in combination as the compound (E).

[0026] The compound (E) may contain a compound (Eb) containing a metal atom (M) other than aluminum, and examples of the compound (Eb) include titanium compounds such as tetrakis(2,4-pentanedionato)titanium, tetramethoxytitanium, tetraethoxytitanium, tetraisopropoxytitanium, tetra-n-butoxytitanium, and tetrakis(2-ethylhexoxy)titanium; and zirconium compounds such as tetrakis(2,4-pentanedionato)zirconium, tetra-n-propoxyzirconium, and tetra-n-butoxyzirconium. These compounds (Eb) may be used alone or in combination of two or more.

[0027] The proportion of compound (Ea) in compound (E) is not particularly limited, and is, for example, preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and may be 100 mol%.

[0028] By hydrolyzing compound (E), at least a portion of the hydrolyzable characteristic groups of compound (E) is converted to hydroxyl groups. Furthermore, the hydrolyzate is condensed to form a compound in which a metal atom (M) is bonded via an oxygen atom (O). Repeated condensation results in the formation of a compound that can be essentially considered a metal oxide. Hydroxyl groups are usually present on the surface of the metal oxide (A) thus formed.

[0029] In this specification, compounds in which the ratio of [the number of moles of oxygen atoms (O) bonded only to metal atoms (M)] / [the number of moles of metal atoms (M)] is 0.8 or more are considered to be included in the metal oxide (A). Here, the oxygen atom (O) bonded only to the metal atom (M) is the oxygen atom (O) in a structure represented by M-O-M, and excludes oxygen atoms bonded to the metal atom (M) and a hydrogen atom (H), such as the oxygen atom (O) in a structure represented by M-O-H. The above ratio in the metal oxide (A) is preferably 0.9 or more, more preferably 1.0 or more, and even more preferably 1.1 or more. There are no particular limitations on the upper limit of this ratio, but it is usually expressed as n / 2, where n is the valence of the metal atom (M).

[0030] For the hydrolysis and condensation to occur, it is important that compound (E) has a hydrolyzable characteristic group. If such a group is not bonded, the hydrolysis and condensation reaction does not occur or occurs very slowly, making it difficult to prepare the target metal oxide (A).

[0031] The hydrolysis condensate of compound (E) may be produced from specific raw materials by, for example, a method employed in a known sol-gel process. The raw material can be at least one selected from the group consisting of compound (E), a partial hydrolysis product of compound (E), a complete hydrolysis product of compound (E), a compound obtained by partial hydrolysis condensation of compound (E), and a compound obtained by partial condensation of a complete hydrolysis product of compound (E).

[0032] It is preferable that the metal oxide (A) to be mixed with the inorganic phosphorus compound (BI)-containing material (the inorganic phosphorus compound (BI) or a composition containing the inorganic phosphorus compound (BI)) described below does not substantially contain phosphorus atoms.

[0033] [Inorganic phosphorus compound (BI)] The inorganic phosphorus compound (BI) has a site capable of reacting with the metal oxide (A), and typically has a plurality of such sites, preferably 2 to 20. Such sites include sites capable of condensation reaction with functional groups (e.g., hydroxyl groups) present on the surface of the metal oxide (A), and examples thereof include halogen atoms directly bonded to phosphorus atoms and oxygen atoms directly bonded to phosphorus atoms. The functional groups (e.g., hydroxyl groups) present on the surface of the metal oxide (A) are usually bonded to metal atoms (M) constituting the metal oxide (A).

[0034] Examples of the inorganic phosphorus compound (BI) include phosphorus oxoacids such as phosphoric acid, diphosphoric acid, triphosphoric acid, polyphosphoric acid in which four or more molecules of phosphoric acid are condensed, phosphorous acid, phosphonic acid, phosphonous acid, phosphinic acid, and phosphinous acid, as well as salts thereof (e.g., sodium phosphate), and derivatives thereof (e.g., halides (e.g., phosphoryl chloride), dehydrates (e.g., diphosphorus pentoxide)). One type may be used alone, or two or more types may be used in combination. Among these, from the viewpoint of improving the stability of the coating liquid (S) described below and the gas barrier properties of the resulting multilayer structure, it is preferable to use phosphoric acid alone, or to use phosphoric acid in combination with another inorganic phosphorus compound (BI). When phosphoric acid is used in combination with another inorganic phosphorus compound (BI), it is preferable that 50 mol % or more of the inorganic phosphorus compound (BI) is phosphoric acid.

[0035] [Reaction Product (D)] The reaction product (D) is obtained by the reaction of the metal oxide (A) with the inorganic phosphorus compound (BI). Compounds produced by the reaction of the metal oxide (A), the inorganic phosphorus compound (BI), and other compounds are also included in the reaction product (D).

[0036] In the infrared absorption spectrum of layer (Y), －１ ~1400cm －１ The maximum absorption wavenumber in the region is 1080 cm －１ ~1130cm －１ For example, in the process of reacting a metal oxide (A) with an inorganic phosphorus compound (BI) to form a reaction product (D), a metal atom (M) derived from the metal oxide (A) and a phosphorus atom (P) derived from the inorganic phosphorus compound (BI) form a bond represented by M-O-P via an oxygen atom (O). As a result, a characteristic absorption band derived from this bond appears in the infrared absorption spectrum of the reaction product (D). The characteristic absorption band based on the M-O-P bond is 1080 cm －１ ~1130cm －１ In particular, when the characteristic absorption band is observed in the 800 cm region where absorption due to the bond between various atoms and oxygen atoms is generally observed, the obtained multilayer structure exhibits excellent gas barrier properties. －１ ~1400cm －１In other words, the multilayer structure of the present invention exhibits even more excellent gas barrier properties when the strongest absorption is in the region of 800 cm in the infrared absorption spectrum of layer (Y). －１ ~1400cm －１ The maximum absorption wave number in the region is 1080 cm －１ ~1130cm －１ In this range, the moisture permeability measured in accordance with ISO15106-5 is 1.0 × 10 －２ g / m ２ ・It tends to be easier to adjust to less than one day.

[0037] In contrast, when a metal compound such as compound (E) or a metal salt and an inorganic phosphorus compound (BI) are mixed in advance and then hydrolyzed and condensed, a complex is obtained in which metal atoms derived from the metal compound and phosphorus atoms derived from the inorganic phosphorus compound (BI) are mixed and reacted almost uniformly. In this case, in the infrared absorption spectrum, －１ ~1400cm －１ The maximum absorption wave number in the region is 1080 cm －１ ~1130cm －１ It will be out of range.

[0038] In the infrared absorption spectrum of layer (Y), －１ ~1400cm －１ The half width of the maximum absorption band in the region is 200 cm from the viewpoint of the gas barrier property of the resulting multilayer structure. －１ Preferably less than 150 cm －１ Less than 100 cm is more preferable. －１ More preferably, 50 cm or less －１ The following are particularly preferred:

[0039] The infrared absorption spectrum of the layer (Y) was measured using a Fourier transform infrared spectrophotometer (Spectrum One manufactured by PerkinElmer Co., Ltd.) at 800 cm －１ ~1400cm －１However, when the measurement cannot be performed by the above method, a reflection measurement such as a reflection absorption method, an external reflection method, or an attenuated total reflection method, or a transmission measurement method such as a Nujol method or a tablet method after scraping off the layer (Y) from the multilayer structure may be performed, but the measurement method is not limited to these.

[0040] Furthermore, the layer (Y) may partially contain the metal oxide (A) and / or the inorganic phosphorus compound (BI) that are not involved in the reaction.

[0041] In the layer (Y), the molar ratio of the metal atoms (M) constituting the metal oxide (A) to the phosphorus atoms derived from the inorganic phosphorus compound (BI) is preferably in the range of [metal atoms (M) constituting the metal oxide (A)]:[phosphorus atoms derived from the inorganic phosphorus compound (BI)] = 1.0:1.0 to 3.6:1.0, more preferably 1.1:1.0 to 3.0:1.0. Excellent gas barrier performance can be obtained within this range. The molar ratio in the layer (Y) can be adjusted by the mixing ratio of the metal oxide (A) to the inorganic phosphorus compound (BI) in the coating liquid (S) described below for forming the layer (Y). The molar ratio in the layer (Y) is usually the same as the ratio in the coating liquid (S) described below.

[0042] The layer (Y) may contain at least one selected from the group consisting of an organic phosphorus compound (BO) and a polymer (F). When the layer (Y) contains at least one selected from the group consisting of an organic phosphorus compound (BO) and a polymer (F), the multilayer structure of the present invention may tend to maintain good gas barrier properties even after being bent. Hereinafter, the property of maintaining gas barrier properties even after being bent may be referred to as "flex resistance."

[0043] [Organophosphorus Compound (BO)] The organophosphorus compound (BO) is preferably a polymer (BOa) having a plurality of phosphorus atoms or an organophosphorus compound (BOb).

[0044] [Polymer (BOa) Having Multiple Phosphorus Atoms] Examples of the phosphorus atom-containing functional group contained in the polymer (BOa) include a phosphate group, a phosphite group, a phosphonate group, a phosphonous group, a phosphinate group, a phosphinous group, and functional groups derived therefrom (for example, salts, (partial) ester compounds, halides (for example, chlorides), and dehydrates). Among these, a phosphate group and a phosphonate group are preferred, and a phosphonate group is more preferred.

[0045] Examples of the polymer (BOa) include polymers of phosphono(meth)acrylic acid esters such as 6-[(2-phosphonoacetyl)oxy]hexyl acrylate, 2-phosphonooxyethyl methacrylate, phosphonomethyl methacrylate, 11-phosphonoundecyl methacrylate, and 1,1-diphosphonoethyl methacrylate; polymers of vinylphosphonic acids such as vinylphosphonic acid, 2-propene-1-phosphonic acid, 4-vinylbenzylphosphonic acid, and 4-vinylphenylphosphonic acid; polymers of vinylphosphinic acids such as vinylphosphinic acid and 4-vinylbenzylphosphinic acid; and phosphorylated starch. The polymer (BOa) may be a homopolymer of a monomer having at least one phosphorus atom-containing functional group, or a copolymer of two or more monomers. Two or more polymers composed of a single monomer may be used in combination as the polymer (BOa). Among these, polymers of phosphono(meth)acrylic acid esters and polymers of vinylphosphonic acids are preferred, polymers of vinylphosphonic acids are more preferred, and polyvinylphosphonic acid is even more preferred. The polymer (BOa) can also be obtained by homopolymerizing or copolymerizing a vinylphosphonic acid derivative such as a vinylphosphonic acid halide or a vinylphosphonic acid ester, followed by hydrolysis.

[0046] The polymer (BOa) may be a copolymer of a monomer having at least one phosphorus atom-containing functional group and another vinyl monomer. Examples of other vinyl monomers that can be copolymerized with the monomer having a phosphorus atom-containing functional group include (meth)acrylic acid, (meth)acrylic acid esters, acrylonitrile, methacrylonitrile, styrene, nucleus-substituted styrenes, alkyl vinyl ethers, alkyl vinyl esters, perfluoroalkyl vinyl ethers, perfluoroalkyl vinyl esters, maleic acid, maleic anhydride, fumaric acid, itaconic acid, maleimide, and phenylmaleimide, among which (meth)acrylic acid esters, acrylonitrile, styrene, maleimide, and phenylmaleimide are preferred.

[0047] In order to obtain a multilayer structure having excellent flex resistance, the proportion of the structural units derived from a monomer having a functional group containing a phosphorus atom in all structural units of the polymer (BOa) is preferably 10 mol % or more, more preferably 40 mol % or more, even more preferably 70 mol % or more, particularly preferably 90 mol % or more, and may be 100 mol %.

[0048] Although there are no particular restrictions on the molecular weight of the polymer (BOa), it is preferable that the number average molecular weight is in the range of 1,000 to 100,000. When the number average molecular weight is in this range, it is possible to achieve both a high level of effect of improving the flex resistance of the multilayer structure of the present invention and, when the coating liquid (S) described below is used, viscosity stability of the coating liquid (S).

[0049] When layer (Y) of the multilayer structure contains polymer (BOa), the ratio WBOa / WBI of the mass WBI of the inorganic phosphorus compound (BI) to the mass WBOa of the polymer (BOa) in layer (Y) preferably satisfies the relationship 0.01 / 99.99≦WBOa / WBI<6.00 / 94.00, and from the viewpoint of excellent barrier performance, it is more preferable that it satisfies the relationship 0.10 / 99.90≦WBOa / WBI<4.50 / 95.50, it is even more preferable that it satisfies the relationship 0.20 / 99.80≦WBOa / WBI<4.00 / 96.00, and it is particularly preferable that it satisfies the relationship 0.50 / 99.50≦WBOa / WBI<3.50 / 96.50. That is, it is preferable to use a small amount of WBOa, 0.01 or more and less than 6.00, while using a large amount of WBI, 94.00 or more and 99.99 or less. Even when the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) have reacted in the layer (Y), the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) constituting the reaction product (D) is regarded as the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa). In this case, the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) used to form the reaction product (D) (the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) before the reaction) is included in the mass of the inorganic phosphorus compound (BI) and / or the organic phosphorus compound (BOa) in the layer (Y).

[0050] [Organic phosphorus compound (BOb)] The organic phosphorus compound (BOb) has a phosphorus atom having at least one hydroxyl group bonded thereto and a polar group bonded thereto via an alkylene chain or polyoxyalkylene chain having from 3 to 20 carbon atoms. The organic phosphorus compound (BOb) has a lower surface free energy than the metal oxide (A), the inorganic phosphorus compound (BI), and their reaction product (D), and segregates to the surface side during the precursor formation process of the layer (Y). As a result, the flex resistance of the multilayer structure of the present invention and the adhesion between the layer (Y) and a layer directly laminated thereto may be improved.

[0051] Specific examples of the organic phosphorus compound (BOb) include 3-hydroxypropylphosphonic acid, 4-hydroxybutylphosphonic acid, 5-hydroxypentylphosphonic acid, 6-hydroxyhexylphosphonic acid, 7-hydroxyheptylphosphonic acid, 8-hydroxyoctylphosphonic acid, 9-hydroxynonylphosphonic acid, 10-hydroxydecylphosphonic acid, 11-hydroxyundecylphosphonic acid, 12-hydroxydodecylphosphonic acid, 13-hydroxydotridecylphosphonic acid, 14-hydroxytetradecylphosphonic acid, 15-hydroxypentadecylphosphonic acid, and 16-hydroxypentadecylphosphonic acid. phosphonic acid, 16-hydroxyhexadecylphosphonic acid, 17-hydroxyheptadecylphosphonic acid, 18-hydroxyoctadecylphosphonic acid, 19-hydroxynonadecylphosphonic acid, 20-hydroxyicosylphosphonic acid, 3-hydroxypropyl dihydrogen phosphate, 4-hydroxybutyl dihydrogen phosphate, 5-hydroxypentyl dihydrogen phosphate, 6-hydroxyhexyl dihydrogen phosphate, 7-hydroxyheptyl dihydrogen phosphate, 8-hydroxyoctyl dihydrogen dihydrogen phosphate, 9-hydroxynonyl dihydrogen phosphate, 10-hydroxydecyl dihydrogen phosphate, 11-hydroxyundecyl dihydrogen phosphate, 12-hydroxydodecyl dihydrogen phosphate, 13-hydroxydotridecyl dihydrogen phosphate, 14-hydroxytetradecyl dihydrogen phosphate, 15-hydroxypentadecyl dihydrogen phosphate, 16-hydroxyhexadecyl dihydrogen phosphate, 17-hydroxyheptadecyl dihydrogen hydrogen phosphate, 18-hydroxyoctadecyl dihydrogen phosphate, 19-hydroxynonadecyl dihydrogen phosphate, 20-hydroxyicosyl dihydrogen phosphate, 3-carboxypropyl phosphonic acid, 4-carboxybutyl phosphonic acid, 5-carboxypentyl phosphonic acid, 6-carboxyhexyl phosphonic acid, 7-carboxyheptyl phosphonic acid, 8-carboxyoctyl phosphonic acid, 9-carboxynonyl phosphonic acid, 10-carboxydecyl phosphonic acid, 11-carboxyundecyl phosphonic acid,Examples of such phosphonic acids include 12-carboxydodecylphosphonic acid, 13-carboxydotridecylphosphonic acid, 14-carboxytetradecylphosphonic acid, 15-carboxypentadecylphosphonic acid, 16-carboxyhexadecylphosphonic acid, 17-carboxyheptadecylphosphonic acid, 18-carboxyoctadecylphosphonic acid, 19-carboxynonadecylphosphonic acid, and 20-carboxyicosylphosphonic acid. These may be used alone or in combination of two or more.

[0052] When the layer (Y) of the multilayer structure contains an organic phosphorus compound (BOb), the ratio MBOb / MBI of the number of moles of the organic phosphorus compound (BOb) to the number of moles of the inorganic phosphorus compound (BI) in the layer (Y) is 1.0×10 －４ ≦MBOb / MBI≦2.0×10 －２ It is preferable that the relationship be satisfied, 3.5 × 10 －４ ≦MBOb / MBI≦1.0×10 －２ It is more preferable that the relationship is 5.0 × 10 －４ ≦MBOb / MBI≦6.0×10 －３ It is more preferable that the relationship be satisfied.

[0053] When layer (Y) contains an organic phosphorus compound (BOb), the C / Al ratio of layer (Y) of the multilayer structure at a depth of 5 nm from the surface on the side not in contact with substrate (X), as measured by X-ray photoelectron spectroscopy (XPS), is preferably in the range of 0.1 to 15.0, more preferably in the range of 0.3 to 10.0, and particularly preferably in the range of 0.5 to 5.0. Having a C / Al ratio on the surface of layer (Y) in the above range may improve the adhesion between layer (Y) and adjacent layers.

[0054] The total thickness of the layers (Y) is preferably 0.1 μm to 4.0 μm, more preferably 0.3 μm to 3.0 μm. By reducing the thickness of the layers (Y), dimensional changes in the multilayer structure during processing such as printing and lamination can be suppressed. The increased flexibility of the multilayer structure also allows its mechanical properties to approach those of the substrate itself. Since the multilayer structure of the present invention has two or more layers (Y), the thickness of each layer (Y) is preferably 0.05 μm or more from the viewpoint of gas barrier properties, and preferably 1.0 μm or less from the viewpoint of flex resistance. The thickness of each layer (Y) can be controlled by the concentration of the coating liquid (S) used to form the layer (Y), as described below, or the application method thereof. The thickness of the layer (Y) can be measured by observing the cross section of the multilayer structure with a scanning electron microscope or a transmission electron microscope.

[0055] [Polymer (F)] Layer (Y) may contain a polymer (F) having at least one functional group selected from the group consisting of a carbonyl group, a hydroxyl group, a carboxyl group, a carboxylic anhydride group, and a salt of a carboxyl group. The polymer (F) is preferably a polymer having at least one functional group selected from the group consisting of a hydroxyl group and a carboxyl group. When layer (Y) contains polymer (F), the flex resistance may be improved.

[0056] Examples of the polymer (F) include polyethylene glycol; polyvinyl alcohol-based polymers such as polyvinyl alcohol, modified polyvinyl alcohol containing 1 mol % to 50 mol % of α-olefin units having 4 or less carbon atoms, and polyvinyl acetal (e.g., polyvinyl butyral); polysaccharides such as cellulose and starch; (meth)acrylic acid-based polymers such as polyhydroxyethyl (meth)acrylate, poly(meth)acrylic acid, and ethylene-acrylic acid copolymer; and maleic acid-based polymers such as hydrolysates of ethylene-maleic anhydride copolymers, hydrolysates of styrene-maleic anhydride copolymers, and hydrolysates of isobutylene-maleic anhydride alternating copolymers. Among these, polyethylene glycol or polyvinyl alcohol-based polymers are preferred.

[0057] The polymer (F) may be a homopolymer of a monomer having a polymerizable group, a copolymer of two or more monomers, or a copolymer of a monomer having at least one functional group selected from the group consisting of a carbonyl group, a hydroxyl group, a carboxyl group, a carboxylic anhydride group, and a salt of a carboxyl group and a monomer not having such a group. Two or more polymers (F) may be mixed and used as the polymer (F).

[0058] The molecular weight of the polymer (F) is not particularly limited, but in order to obtain a multilayer structure having better gas barrier properties and mechanical strength, the weight average molecular weight of the polymer (F) is preferably at least 5000, more preferably at least 8000, and even more preferably at least 10000. The upper limit of the weight average molecular weight of the polymer (F) is not particularly limited, and is, for example, 1,500,000.

[0059] From the viewpoint of maintaining a good appearance of the multilayer structure, the content of polymer (F) in layer (Y) is preferably less than 50% by mass, more preferably 20% by mass or less, and even more preferably 10% by mass or less, based on the mass of layer (Y). Polymer (F) may or may not react with components in layer (Y).

[0060] The layer (Y) may further contain other components. Examples of other components that can be contained in the layer (Y) include inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, hydrogencarbonates, sulfates, hydrogensulfates, and borates; organic acid metal salts such as oxalates, acetates, tartrates, and stearates; metal complexes such as cyclopentadienyl metal complexes (e.g., titanocene) and cyano metal complexes (e.g., Prussian blue); layered clay compounds; crosslinking agents; polymer compounds other than the polymer (BOa) and the polymer (F); plasticizers; antioxidants; ultraviolet absorbers; and flame retardants. The content of the above-mentioned other components in the layer (Y) in the multilayer structure is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, and may be 3% by mass or less, 1% by mass or less, or 0% by mass (no other components).

[0061] The laminate constituting the multilayer structure of the present invention may have a layer (W) containing at least one selected from the group consisting of an organic phosphorus compound (BO) and a polymer (F) directly laminated on the surface of the layer (Y) opposite the substrate (X). The provision of the layer (W) may improve flex resistance or improve adhesion to the adhesive layer (I) described below. The laminate constituting the multilayer structure of the present invention may have an adhesive layer (AC) between the substrate (X) and the layer (Y). The provision of the adhesive layer (AC) may improve adhesion between the substrate (X) and the layer (Y).

[0062] [Layer (W)] When the laminate includes the layer (W), the layer (W) is preferably directly laminated on the layer (Y). Suitable embodiments of the organophosphorus compound (BO) and the polymer (F) that can be contained in the layer (W) are as described above.

[0063] The layer (W) may further contain other components. Examples of other components include inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, hydrogencarbonates, sulfates, hydrogensulfates, and borates; organic acid metal salts such as oxalates, acetates, tartrates, and stearates; metal complexes such as cyclopentadienyl metal complexes (e.g., titanocene) and cyanometal complexes (e.g., Prussian blue); layered clay compounds; crosslinking agents; polymer compounds other than the polymer (BOa) and the polymer (F); plasticizers; antioxidants; ultraviolet absorbers; and flame retardants. The content of the other components in the layer (W) is preferably 20% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less. It may be 2% by mass or less, 1% by mass or less, or 0% by mass (no other components).

[0064] When the laminate includes the layer (W), the thickness thereof is preferably 0.005 μm or more from the viewpoint of improving the flex resistance of the multilayer structure of the present invention. Although the upper limit of the thickness of the layer (W) is not particularly limited, it is economically preferable to set the upper limit of the thickness of the layer (W) to 1.0 μm, since the effect of improving the flex resistance reaches saturation at 1.0 μm or more.

[0065] [Layer (Y')] The layer (Y') can be formed by vapor deposition of an inorganic material. Examples of the inorganic material include metal oxides (e.g., silicon oxide, aluminum oxide), metal nitrides (e.g., silicon nitride), metal nitride oxides (e.g., silicon oxynitride), and metal carbonitrides (e.g., silicon carbonitride). Among these, an inorganic vapor deposition layer (Y') formed of aluminum oxide, silicon oxide, magnesium oxide, or silicon nitride is preferred from the viewpoint of excellent transparency.

[0066] The method for forming the inorganic vapor deposition layer (Y′) is not particularly limited, and examples thereof include physical vapor deposition methods such as vacuum deposition (e.g., resistance heating deposition, electron beam deposition, molecular beam epitaxy, etc.), sputtering, and ion plating; and chemical vapor deposition methods such as thermal chemical vapor deposition (e.g., catalytic chemical vapor deposition), photochemical vapor deposition, plasma chemical vapor deposition (e.g., capacitively coupled plasma, inductively coupled plasma, surface wave plasma, electron cyclotron resonance, dual magnetron, atomic layer deposition, etc.), and metalorganic chemical vapor deposition.

[0067] The thickness of the inorganic vapor deposition layer (Y') varies depending on the types of components constituting the inorganic vapor deposition layer, but is preferably 0.002 μm to 0.5 μm, more preferably 0.005 μm to 0.2 μm, and even more preferably 0.01 μm to 0.1 μm. A thickness within this range may be selected so that the barrier properties and mechanical properties of the multilayer structure are improved. When the thickness of the inorganic vapor deposition layer (Y') is 0.002 μm or more, the barrier properties of the inorganic vapor deposition layer (Y') against oxygen and water vapor tend to be improved. Furthermore, when the thickness of the inorganic vapor deposition layer (Y') is 0.5 μm or less, the barrier properties of the inorganic vapor deposition layer (Y') tend to be maintained even after bending.

[0068] [Adhesive Layer AC] The adhesive constituting the adhesive layer (AC) is not particularly limited as long as it has adhesive properties between the substrate (X) and the layer (Y) and layer (Y'), and examples thereof include polyurethane adhesives, polyester adhesives, etc. Adhesion may be further enhanced by adding a small amount of additives such as a known silane coupling agent to these adhesives. Examples of the silane coupling agent include silane coupling agents having reactive groups such as an isocyanate group, an epoxy group, an amino group, a ureido group, and a mercapto group.

[0069] Although known polyurethane adhesives can be used, it is preferable to use a two-component polyurethane adhesive in which a polyisocyanate component and a polyol component are mixed and reacted. Commercially available two-component polyurethane adhesives can be used, such as Takelac (registered trademark) and Takenate (registered trademark) manufactured by Mitsui Chemicals, Inc.

[0070] Known polyester adhesives can be used, and commercially available products include, for example, Elitel (registered trademark) KT-0507, KT-8701, KT-8803, KT-9204, KA-5034, KA-3556, KA-1449, KA-5071S, and KZA-1449S (all manufactured by Unitika Ltd.), Vylonal (registered trademark) MD-1200 and Vylonal MD-1480 (all manufactured by Toyobo Co., Ltd.), PES Resin A124GP, and PES Resin A684G (manufactured by Takamatsu Oil & Fat Co., Ltd.). Adding a vinyl alcohol resin, particularly polyvinyl alcohol, to a polyester adhesive can sometimes further enhance adhesion. When a vinyl alcohol resin and a polyester resin are used simultaneously, the mass ratio (vinyl alcohol resin / polyester resin) is preferably 1 / 99 or more and 50 / 50 or less, from the viewpoint of maintaining good adhesion while exhibiting higher peel strength. The polyester resin is preferably a polyester resin having a carboxyl group from the viewpoint of affinity with the vinyl alcohol resin. When used as an adhesive, the polyester resin is preferably an aqueous dispersion. When the polyester resin is an aqueous dispersion, affinity with the polyvinyl alcohol resin tends to be better. The thickness of the adhesive layer (AC) is preferably 0.001 μm to 10.0 μm, more preferably 0.01 μm to 5.0 μm.

[0071] [Laminate (α)] The laminate (α) constituting the multilayer structure of the present invention includes a substrate (X) and a layer (Y). The laminate is not particularly limited as long as it includes the substrate (X) and the layer (Y). However, it is preferable that the substrate (X) and the layer (Y) are laminated directly or via an adhesive layer (AC). In addition, in the laminate, the layer (W) may be laminated directly on the exposed surface side of the layer (Y). Providing the layer (W) on the exposed surface side of the layer (Y) or layer (Y') may improve the flex resistance of the multilayer structure of the present invention and may improve the adhesion to the adhesive layer (I), which will be described later. From the viewpoint of exhibiting higher water vapor barrier properties while maintaining flexibility, the laminate is preferably a laminate having the layer (Y) on both sides of the substrate (X).

[0072] Specific examples of the laminate are shown below, but each layer may be provided in a plurality of layers. Here, " / " means that they are directly laminated, and " / / " means that they are directly laminated or laminated via an adhesive layer (AC). (1) Substrate (X) / / Layer (Y) (2) Substrate (X) / / Layer (Y) / Layer (W) (3) Layer (Y) / / Substrate (X) / / Layer (Y) (4) Layer (Y) / / Substrate (X) / / Layer (Y) / Layer (W) (5) Layer (W) / Layer (Y) / / Substrate (X) / / Layer (Y) / Layer (W)

[0073] [Laminate (β)] The laminate (β) constituting the multilayer structure of the present invention includes a substrate (X) and a layer (Y'). The laminate is not particularly limited as long as it includes the substrate (X) and the layer (Y'). However, it is preferable that the substrate (X) and the layer (Y') are laminated directly or via an adhesive layer (AC). In addition, the laminate may include a layer (W) directly laminated on the exposed surface of the layer (Y'). Providing the layer (W) on the exposed surface of the layer (Y') may improve the flex resistance of the multilayer structure of the present invention and its adhesion to the adhesive layer (I), which will be described later. From the viewpoint of exhibiting higher water vapor barrier properties while maintaining flexibility, the laminate is preferably a laminate having a layer (Y') on both sides of the substrate (X).

[0074] Specific examples of the laminate are shown below, but each layer may be provided in a plurality of layers. Here, " / " means that they are directly laminated, and " / / " means that they are directly laminated or laminated via an adhesive layer (AC). (1) Substrate (X) / / Layer (Y') (2) Substrate (X) / / Layer (Y') / Layer (W) (3) Layer (Y') / / Substrate (X) / / Layer (Y') (4) Layer (Y') / / Substrate (X) / / Layer (Y') / Layer (W) (5) Layer (W) / Layer (Y') / / Substrate (X) / / Layer (Y') / Layer (W)

[0075] [Adhesive layer (I)] The multilayer structure of the present invention comprises the laminate (α) and laminate (β), and the laminates are laminated via an adhesive layer (I). When a plurality of adhesive layers (I) are provided, the adhesive layers (I) may be the same or different. The multilayer structure of the present invention tends to exhibit high water vapor barrier properties by laminating at least one or more laminates (α) and laminates (β) via the adhesive layer (I). Furthermore, when the adhesive layer (I) is a layer provided with a two-component adhesive, a highly transparent multilayer structure can be produced by undergoing the step (III) described below.

[0076] The adhesive material constituting the adhesive layer (I) preferably contains at least one selected from the group consisting of polyurethane, polyester, acrylic resin, epoxy resin, polyolefin elastomer, ethylene-vinyl acetate copolymer, polyvinyl butyral, and ionomer. The adhesive layer (I) is preferably an adhesive layer formed by a dry lamination method or a thermoplastic resin layer for lamination by vacuum lamination, and from the viewpoint of improving flexibility, the adhesive layer (I) is more preferably an adhesive layer formed by a dry lamination method.

[0077] When the adhesive layer (I) is an adhesive layer formed by the dry lamination method, the material used for the adhesive layer (I) may be any transparent material that can be cured by heating, light, or the like, and has strong adhesive strength. For example, an adhesive or pressure-sensitive adhesive that bonds by curing an isocyanate, heating, light, or the like, may be used, and a two-component adhesive is preferred. Specifically, a urethane-based adhesive, an ester-based adhesive, an acrylic-based adhesive, or the like can be used. Among these, urethane-based adhesives and polyester-based adhesives are preferred, and a two-component reactive polyurethane-based adhesive in which a polyisocyanate component and a polyol component are mixed and reacted is more preferred.

[0078] When the adhesive layer (I) is an adhesive layer formed by dry lamination, the thickness of each adhesive layer (I) is preferably 0.5 μm to 20 μm, more preferably 0.5 μm to 15 μm, and even more preferably 1 μm to 10 μm. When the thickness of each adhesive layer (I) is 0.5 μm or more, the adhesiveness tends to be improved, and when it is 20 μm or less, the flexibility of the resulting multilayer structure tends to be improved.

[0079] When the adhesive layer (I) is an adhesive layer formed by vacuum lamination, the material used for the adhesive layer (I) may be any transparent material that melts and hardens when heated, and has strong adhesive strength. In particular, materials commonly used as encapsulants for solar cells and the like are suitable. For example, it is preferable for the material to contain at least one selected from the group consisting of polyolefin elastomer, ethylene-vinyl acetate copolymer, polyvinyl butyral, and ionomer.

[0080] When the adhesive layer (I) is an adhesive layer formed by vacuum lamination, the thickness of each adhesive layer (I) is preferably 5 μm to 600 μm, more preferably 10 μm to 500 μm, and even more preferably 15 μm to 400 μm. When the thickness of each adhesive layer (I) is 5 μm or more, the adhesiveness tends to be improved, and when it is 600 μm or less, the flexibility of the resulting multilayer structure tends to be improved. For example, when a device such as a solar cell is produced by laminating other components by vacuum lamination, forming the adhesive layer (I) by vacuum lamination can be performed in the same process as the process of laminating the other components, thereby reducing the number of steps. On the other hand, the thickness tends to be thicker than that of dry lamination, and flexibility may be reduced.

[0081] The number of adhesive layers (I) provided between laminates is not particularly limited, but is preferably 3 or less, more preferably 2 or less, and even more preferably 1. If there are 3 or more, the process becomes complicated and the cost tends to increase. When the number of laminates is 3 or more, an adhesive layer (I) can be provided between each laminate based on the above-mentioned concept. When there are multiple adhesive layers (I), they may be the same or different.

[0082] When the adhesive layer (I) is an adhesive layer formed by dry lamination, the thickness of the multilayer structure of the present invention (total thickness of all layers) is preferably 15 μm or more, more preferably 20 μm or more, and even more preferably 30 μm or more. The thickness of the multilayer structure of the present invention is preferably 500 μm or less, more preferably 400 μm or less, and even more preferably 300 μm or less. A thickness of 15 μm or more tends to improve mechanical strength and processability during production of the multilayer structure. A thickness of 500 μm or less tends to improve flexibility of the multilayer structure.

[0083] When the adhesive layer (I) is an adhesive layer formed by vacuum lamination, the thickness of the multilayer structure of the present invention (total thickness of all layers) is preferably 20 μm or more, more preferably 30 μm or more, and even more preferably 40 μm or more. The thickness of the multilayer structure of the present invention is preferably 1000 μm or less, more preferably 900 μm or less, and particularly preferably 700 μm or less. When the thickness is 20 μm or more, the mechanical strength is improved and the processability during production of the multilayer structure tends to be improved. Furthermore, when the thickness is 1000 μm or less, the flexibility of the multilayer structure tends to be improved.

[0084] The moisture permeability of the multilayer structure of the present invention measured at 40°C and 90% RH is 2.0 x 10 －３ g / m ２ ・day or less, 1.0 × 10 －３ g / m ２ ・day or less is preferable, 9.0 × 10 －４ g / m ２ The moisture permeability can be measured using a DELTAPERM manufactured by TECHNOLOX in accordance with ISO 15106-5:2015. The moisture permeability is preferably 1.0 × 10 －６ g / m ２ ・Even if it is more than 5.0 x 10 －５ g / m ２ ・Even if it is more than 1.0 × 10 －４ g / m ２ The moisture permeability may be 2.0 × 10 －３ g / m ２As a means for making the absorption coefficient 800 cm or less, for example, two or more of the above laminates are provided, and the absorption coefficient 800 cm or less in the infrared absorption spectrum of the layer (Y) is －１ ~1400cm －１ The maximum absorption wavenumber in the region is 1080 cm －１ ~1130cm －１ and providing an additional layer with low moisture permeability.

[0085] The total light transmittance of the multilayer structure of the present invention is 87% or more, more preferably 88% or more, and even more preferably 89% or more. The total light transmittance can be measured in accordance with JIS K 7361-1:1997 using a haze meter HR-100 manufactured by Murakami Color Research Laboratory Co., Ltd. The total light transmittance may be 100% or less, 98% or less, or 95% or less. When the adhesive layer (I) is an adhesive layer formed by a dry lamination method, examples of means for achieving the total light transmittance of 87% or more include extending the drying time and performing aging in two stages. When the adhesive layer (I) is an adhesive layer formed by a vacuum lamination method, examples of means for achieving the total light transmittance of 87% or more include controlling the temperature and pressure.

[0086] The haze of the multilayer structure of the present invention is 7% or less, more preferably 6.8% or less, and even more preferably 6.5% or more. The total light transmittance can be measured in accordance with JIS K 7136:2000 using a haze meter HR-100 manufactured by Murakami Color Research Laboratory Co., Ltd. The haze may be 0.01% or more, 0.1% or more, or 1% or more. When the adhesive layer (I) is an adhesive layer formed by a dry lamination method, examples of means for adjusting the haze to 7% or less include extending the drying time and performing aging in two stages. When the adhesive layer (I) is an adhesive layer formed by a vacuum lamination method, examples of means for adjusting the haze to 7% or less include controlling the temperature and pressure.

[0087] [Configuration of multilayer structure] The multilayer structure of the present invention comprises at least one of the laminates (α) and (β), and the laminates (α) and (β) are laminated via an adhesive layer (I). Specific examples of the configuration of the multilayer structure of the present invention are shown below, but each specific example may be configured in a combination of multiple components. " / " means that they are directly laminated. Suitable embodiments of the laminate are as described above. (1) Laminate (α) / adhesive layer (I) / laminate (β) (2) Laminate (β) / adhesive layer (I) / laminate (α) / adhesive layer (I) / laminate (β)

[0088] The number of layers in the laminate is not particularly limited, but is preferably 6 or less, more preferably 4 or less, and even more preferably 3 or less. By reducing the number of layers in the laminate, the number of adhesive layers (I) can be reduced, and high light transmittance and high flexibility can be maintained. From the viewpoint of achieving both flexibility and barrier properties, it is preferable that the laminate (α) has a layer (Y) on both sides of the substrate (X), and the laminate (β) has a layer (Y') on both sides of the substrate (X).

[0089] [Method for producing a multilayer structure] The matters described for the multilayer structure of the present invention are applicable to the production method of the present invention, so duplicated explanations may be omitted. In addition, the matters described for the production method of the present invention are applicable to the multilayer structure of the present invention.

[0090] The method for producing the multilayer structure of the present invention may include, for example, a production method including the steps of: applying a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent to a substrate (X), and removing the solvent to form a precursor layer of the layer (Y); heat-treating the precursor layer of the layer (Y) to form the layer (Y); and laminating at least two laminates obtained through the step (II) via an adhesive layer (I). When producing a multilayer structure containing an organic phosphorus compound (BO) or a polymer (F), the coating liquid (S) used in the step (I) may contain the organic phosphorus compound (BO) or the polymer (F), or the method may include a step (IV) of preparing a coating liquid (T) containing the organic phosphorus compound (BO) or the polymer (F) and applying it to the surface of the precursor layer of the layer (Y) obtained in the step (I) or to the surface of the layer (Y) obtained in the step (II). In addition, when an adhesive layer (AC) is provided between the substrate (X) and the layer (Y), a step of providing the adhesive layer (AC) on the substrate (X) may be included before the step (I).

[0091] [Step (I)] In step (I), a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent is applied to a substrate (X), and the solvent is then removed to form a precursor layer of layer (Y). The coating liquid (S) is obtained by mixing the metal oxide (A), the inorganic phosphorus compound (BI), and the solvent.

[0092] Specific means for preparing the coating liquid (S) include a method of mixing a dispersion of the metal oxide (A) with a solution containing the inorganic phosphorus compound (BI); a method of adding the inorganic phosphorus compound (BI) to a dispersion of the metal oxide (A) and mixing them, etc. The temperature during mixing is preferably 50°C or less, more preferably 30°C or less, and even more preferably 20°C or less. The coating liquid (S) may contain other compounds (e.g., an organic phosphorus compound (BO) or a polymer (F)), and may contain at least one acid compound (Q) selected from the group consisting of acetic acid, hydrochloric acid, nitric acid, trifluoroacetic acid, and trichloroacetic acid, as necessary.

[0093] The dispersion of metal oxide (A) can be prepared, for example, according to a method employed in a known sol-gel method, by mixing compound (E), water, and, if necessary, an acid catalyst or an organic solvent, and condensing or hydrolytically condensing compound (E). When a dispersion of metal oxide (A) is obtained by condensing or hydrolytically condensing compound (E), the obtained dispersion may be subjected to a specific treatment (such as peptization in the presence of the above-mentioned acid compound (Q)) if necessary. The solvent used to prepare the dispersion of metal oxide (A) is not particularly limited, but alcohols such as methanol, ethanol, and isopropanol; water; or a mixed solvent thereof are preferred.

[0094] The solvent used for the solution containing the inorganic phosphorus compound (BI) may be appropriately selected depending on the type of inorganic phosphorus compound (BI), but preferably contains water. The solvent may contain an organic solvent (e.g., alcohols such as methanol) as long as it does not interfere with the dissolution of the inorganic phosphorus compound (BI).

[0095] The solid content concentration of the coating liquid (S) is preferably 1% by mass to 20% by mass, more preferably 2% by mass to 15% by mass, and even more preferably 3% by mass to 10% by mass, from the viewpoints of the storage stability of the coating liquid (S) and its coatability to a substrate. The solid content concentration can be calculated, for example, by dividing the mass of the solid content remaining after distilling off the solvent from the coating liquid (S) by the mass of the coating liquid (S) used in the treatment.

[0096] The viscosity of the coating liquid (S), measured with a Brookfield rotational viscometer (SB type viscometer: rotor No. 3, rotation speed 60 rpm), at the temperature during coating is preferably 3000 mPa·s or less, more preferably 2500 mPa·s or less, and even more preferably 2000 mPa·s or less. Having a viscosity of 3000 mPa·s or less improves the leveling properties of the coating liquid (S), allowing a multilayer structure with superior appearance to be obtained. Furthermore, the viscosity of the coating liquid (S) is preferably 50 mPa·s or more, more preferably 100 mPa·s or more, and even more preferably 200 mPa·s or more.

[0097] In the coating liquid (S), the molar ratio of aluminum atoms to phosphorus atoms is preferably in the range of 1.0:1.0 to 3.6:1.0, more preferably 1.1:1.0 to 3.0:1.0, and particularly preferably 1.11:1.00 to 1.50:1.00. The molar ratio of aluminum atoms to phosphorus atoms can be calculated by subjecting a dried product of the coating liquid (S) to X-ray fluorescence analysis.

[0098] The method for applying the coating liquid (S) is not particularly limited, and any known method can be used, such as casting, dipping, roll coating, gravure coating, screen printing, reverse coating, spray coating, kiss coating, die coating, metalling bar coating, chamber doctor combined coating, curtain coating, and bar coating.

[0099] The method for removing the solvent (drying treatment) after application of the coating liquid (S) is not particularly limited, and any known drying method can be applied. Examples of the drying method include hot air drying, hot roll contact drying, infrared heating, and microwave heating.

[0100] The drying temperature is preferably lower than the flow initiation temperature of the substrate (X). The drying temperature after application of the coating liquid (S) may be, for example, about 60°C to 180°C, more preferably 60°C or higher but lower than 140°C, even more preferably 70°C or higher but lower than 130°C, and particularly preferably 80°C or higher but lower than 120°C. The drying time is not particularly limited, but is preferably 1 second or higher but lower than 1 hour, more preferably 5 seconds or higher but lower than 15 minutes, and even more preferably 5 seconds or higher but lower than 300 seconds. In particular, when the drying temperature is 100°C or higher (e.g., 100°C to 140°C), the drying time is preferably 1 second or higher but lower than 4 minutes, more preferably 5 seconds or higher but lower than 4 minutes, and even more preferably 5 seconds or higher but lower than 3 minutes. When the drying temperature is lower than 100°C (e.g., 60°C to 99°C), the drying time is preferably 3 minutes or higher but lower than 1 hour, more preferably 6 minutes or higher but lower than 30 minutes, and even more preferably 8 minutes or higher but lower than 25 minutes. When the drying treatment conditions of the coating liquid (S) are within the above range, a multilayer structure having better gas barrier properties tends to be obtained. By removing the solvent through the above drying, a precursor layer of the layer (Y) is formed.

[0101] When layers (Y) are laminated on both sides of a substrate (X), a coating liquid (S) is applied to one side of the substrate (X) and the solvent is removed to form a first layer (precursor layer of the first layer (Y)), and then the coating liquid (S) is applied to the other side of the substrate (X) and the solvent is removed to form a second layer (precursor layer of the second layer (Y)). The compositions of the coating liquids (S) applied to each side may be the same or different. The coating liquid (S) may be applied to both sides of the substrate (X) at once and the solvent may be removed to simultaneously form precursor layers for two layers (Y).

[0102] [Step (II)] In step (II), the precursor layer of layer (Y) formed in step (II) is heat-treated to form layer (Y). In step (II), a reaction to produce reaction product (D) proceeds. To ensure that the reaction proceeds sufficiently, the heat treatment temperature is preferably 140°C or higher, more preferably 170°C or higher, even more preferably 180°C or higher, and particularly preferably 190°C or higher. A low heat treatment temperature increases the time required to achieve a sufficient reaction rate, resulting in reduced productivity. The heat treatment temperature varies depending on the type of substrate (X). For example, when a thermoplastic resin film made of a polyamide resin is used as the substrate (X), the heat treatment temperature is preferably 270°C or lower. When a thermoplastic resin film made of a polyester resin is used as the substrate (X), the heat treatment temperature is preferably 240°C or lower. The heat treatment may be performed in an air atmosphere, a nitrogen atmosphere, an argon atmosphere, or the like. The heat treatment time is preferably 1 second to 1 hour, more preferably 1 second to 15 minutes, and even more preferably 5 seconds to 300 seconds.

[0103] Step (II) preferably includes a first heat treatment step (II-1) and a second heat treatment step (II-2). When the heat treatment is performed in two or more stages, the temperature of the second heat treatment (hereinafter referred to as the second heat treatment) is preferably higher than the temperature of the first heat treatment (hereinafter referred to as the first heat treatment), more preferably 15°C or more higher than the temperature of the first heat treatment, even more preferably 20°C or more higher, and particularly preferably 30°C or more higher.

[0104] The heat treatment temperature in step (II) (the first heat treatment temperature in the case of two or more heat treatment stages) is preferably higher than the drying temperature in step (I), preferably by 30°C or more, more preferably by 50°C or more, even more preferably by 55°C or more, and particularly preferably by 60°C or more, in order to obtain a multilayer structure having good properties.

[0105] When the heat treatment in step (II) is performed in two or more stages, the temperature of the first heat treatment is preferably 140°C or higher but lower than 200°C, and the temperature of the second heat treatment is more preferably 180°C or higher but lower than 270°C. The temperature of the second heat treatment is preferably higher than the first heat treatment temperature, more preferably 15°C or higher, and even more preferably 25°C or higher. In particular, when the heat treatment temperature is 200°C or higher, the heat treatment time is preferably 0.1 seconds to 10 minutes, more preferably 0.5 seconds to 15 minutes, and even more preferably 1 second to 3 minutes. When the heat treatment temperature is lower than 200°C, the heat treatment time is preferably 1 second to 15 minutes, more preferably 5 seconds to 10 minutes, and even more preferably 10 seconds to 5 minutes.

[0106] [Step (III)] In step (III), at least two of the laminates obtained through step (II) are laminated via an adhesive layer (I). A known method can be used to laminate at least two laminates via an adhesive layer (I). For example, a method of applying a two-component adhesive to the laminate, removing the solvent to form an adhesive layer (I), and then laminating by a known method, or a method of using an adhesive film (e.g., a sealant) as the adhesive layer (I), superimposing it on the laminate, and then laminating by vacuum lamination, etc. can be mentioned.

[0107] When a two-component adhesive is used in step (III), the method includes a step (III-AI) of applying a two-component adhesive to the surface of one of the laminates and removing the solvent to form an adhesive layer (I), and a step (III-AII) of aging after laminating the laminates via the adhesive layer (I), wherein the drying temperature in step (III-AI) is 45 ° C. or higher and 150 ° C. or lower, and the aging conditions in step (III-AII) preferably include condition 1 in which aging is performed at a temperature of 10 ° C. or higher but lower than 35 ° C. for 2 days to 30 days, and condition 2 in which aging is performed at a temperature of 35 ° C. or higher and 70 ° C. or lower for 2 days to 30 days. When laminating laminates together using a two-component adhesive, depending on the drying and aging conditions, it may be difficult to achieve a total light transmittance of 87% or higher as measured in accordance with JIS K 7361-1:1997, and the conditions in step (III) are extremely important. The drying temperature is preferably 45°C to 150°C, more preferably 50°C to 140°C, and even more preferably 55°C to 130°C. When the drying temperature is 45°C or higher, the drying rate of the solvent increases, and deterioration of appearance due to residual solvent tends to be suppressed. Furthermore, when the drying temperature is 150°C or lower, dimensional changes during drying tend to be suppressed. The drying time depends on the drying temperature, but is preferably 10 seconds to 30 minutes, more preferably 1 minute to 25 minutes, and even more preferably 4 minutes to 20 minutes. By controlling the drying time within the above range, deterioration of appearance due to residual solvent tends to be suppressed and production efficiency tends to be improved. Furthermore, aging is preferably performed in two stages, and the temperature in the first stage (condition 1) is preferably 10°C or higher but lower than 35°C, more preferably 15°C or higher but lower than 33°C, and even more preferably 20°C or higher but lower than 30°C. The aging time in the first stage (condition 1) is preferably 1 day or more and 30 days or less, more preferably 3 days or more and 25 days or less, and even more preferably 5 days or more and 20 days or less. By controlling the aging temperature and time in the first stage within the above ranges, the curing reaction of the adhesive can be allowed to proceed slowly, which tends to both suppress deterioration of appearance due to gas generation during the curing reaction and improve production efficiency. The temperature in the second stage (condition 2) is preferably 35°C or more and 70°C or less, more preferably 36°C or more and 65°C or less, and even more preferably 37°C or more and 60°C or less.The aging time in the second stage (condition 2) is preferably 1 day or more and 30 days or less, more preferably 2 days or more and 25 days or less, and even more preferably 3 days or more and 20 days or less. By controlling the aging temperature and time in the second stage (condition 2) within the above ranges, the curing reaction of the adhesive can be greatly promoted, and there is a tendency for both improvement in adhesion and improvement in production efficiency to be achieved.

[0108] A total of three or more laminates can be laminated on both sides of the laminate via adhesive layers (I). For example, a two-component adhesive can be applied to one laminate, the solvent can be removed, and the laminate can be laminated by a known method. Then, a two-component adhesive can be applied to another laminate, the solvent can be removed, and the laminate can be laminated on the other side of the laminate by a known method. The adhesive compositions applied to each side can be the same or different. Two adhesive layers (I) can be laminated simultaneously, or three laminates can be laminated simultaneously.

[0109] When a vacuum lamination method is used in step (III), it is preferable to include step (III-B) in which an adhesive film is used as the adhesive layer (I), and the adhesive film is superimposed on the laminate and heated and pressed under vacuum to form the adhesive layer (I). The temperature and pressure are not particularly limited depending on the material used for the adhesive layer (I), but the temperature is preferably 50°C to 200°C, more preferably 70°C to 190°C, and even more preferably 80°C to 180°C. The pressure is preferably 5 kPa to 200 kPa, more preferably 10 kPa to 170 kPa, and even more preferably 15 kPa to 150 kPa. By controlling the temperature and pressure within the above ranges, it is possible to achieve both good adhesive strength and high total light transmittance.

[0110] [Step (IV)] When the above-mentioned production method uses an organic phosphorus compound (BO), a polymer (F), and / or other components, the method may include a step (IV) of applying a coating liquid (T) obtained by mixing the organic phosphorus compound (BO), the polymer (F), and / or other components and a solvent onto the precursor layer of the layer (Y) obtained in step (I), the layer (Y) obtained in step (II), or the precursor layer of the layer (Y) after step (II-1), followed by a drying treatment. When step (IV) is performed after step (II-1), it is preferable to perform step (II-2) after the drying treatment of step (IV).

[0111] The solvent used in the coating liquid (T) may be appropriately selected depending on the types of the organic phosphorus compound (BO), the polymer (F) and / or other components, but is preferably an alcohol such as methanol, ethanol, isopropanol, or the like; water; or a mixed solvent thereof.

[0112] From the viewpoint of storage stability and coatability of the solution, the solid content concentration in the coating liquid (T) is preferably 0.01% by mass to 60% by mass, more preferably 0.1% by mass to 50% by mass, and even more preferably 0.2% by mass to 40% by mass. The solid content concentration can be determined by the same method as that described for the coating liquid (S).

[0113] As with the application of the coating liquid (S), the method for applying the coating liquid (T) is not particularly limited, and known methods can be used.

[0114] As the conditions for the method of removing the solvent (drying treatment) after application of the coating liquid (T) in the step (IV), the same method as the drying treatment conditions after application of the coating liquid (S) in the step (I) can be applied.

[0115] [Electronic Device] An electronic device using the multilayer structure of the present invention comprises an electronic device main body and a protective sheet that protects the surface of the electronic device main body. The protective sheet for an electronic device of the present invention includes the multilayer structure of the present invention. The protective sheet for an electronic device of the present invention may be composed only of the multilayer structure of the present invention, or may be composed of the multilayer structure of the present invention and other members.

[0116] The electronic device of the present invention may be a photoelectric conversion device, an information display device, or a lighting device. Examples of photoelectric conversion devices include various solar cells and other photoelectric conversion devices. Examples of information display devices include liquid crystal displays, organic electroluminescence displays, plasma displays, electronic paper, and other information display devices. Examples of lighting devices include LED lighting, organic electroluminescence lighting, and other lighting devices.

[0117] The electronic device of the present invention can be particularly preferably used as a flexible electronic device. Here, a flexible electronic device refers to an electronic device that has flexibility and can maintain its functionality even when bent. Whether an electronic device is flexible can be determined, for example, by whether delamination or creases occur when a sheet-like electronic device is rolled into a roll with an inner diameter of 7 cm, as described in the Examples.

[0118] A protective sheet containing a multilayer structure has excellent gas barrier properties and water vapor barrier properties. Furthermore, the protective sheet has high transparency. Therefore, by using a protective sheet containing a multilayer structure, an electronic device with high light transmittance and minimal deterioration can be obtained, even in harsh environments.

[0119] The multilayer structure can also be used as a film called a substrate film, such as a substrate film for LCDs, organic EL displays, or electronic paper. In this case, the multilayer structure may serve as both a substrate and a protective sheet. Furthermore, the electronic device to be protected by the protective sheet is not limited to the above examples, and may also be, for example, an IC tag, an optical communication device, a fuel cell, or the like.

[0120] The protective sheet may include a surface protective layer disposed on one surface of the multilayer structure. The surface protective layer is preferably a layer made of a scratch-resistant resin. Furthermore, the surface protective layer of a device that may be used outdoors, such as a solar cell, is preferably made of a resin with high weather resistance (e.g., light resistance). Furthermore, when protecting a surface that requires light transmission, a surface protective layer with high light transmittance is preferred. Examples of materials for the surface protective layer (surface protective film) include acrylic resin, polycarbonate, polyethylene terephthalate, polyethylene naphthalate, ethylene-tetrafluoroethylene copolymer (ETFE), polytetrafluoroethylene, 4-fluoroethylene-perchloroalkoxy copolymer, 4-fluoroethylene-6-fluoropropylene copolymer, 2-ethylene-4-fluoroethylene copolymer, poly-3-chlorofluoroethylene, polyvinylidene fluoride, and polyvinyl fluoride. Among these, an ethylene-tetrafluoroethylene copolymer is preferred from the viewpoints of weather resistance and light transmittance.

[0121] To enhance the durability of the surface protective layer, various additives (e.g., ultraviolet absorbers) may be added to the surface protective layer. A preferred example of a highly weather-resistant surface protective layer is an acrylic resin layer to which an ultraviolet absorber has been added. Examples of ultraviolet absorbers include, but are not limited to, benzotriazole-based, benzophenone-based, salicylate-based, cyanoacrylate-based, nickel-based, and triazine-based ultraviolet absorbers. In addition, other stabilizers, light stabilizers, antioxidants, etc. may be used in combination.

[0122] The configuration of the protective sheet is not particularly limited, but the following configurations may be preferably used, for example: (1) Multilayer structure (2) ETFE layer / adhesive layer / multilayer structure EVA is preferably used as the adhesive layer.

[0123] The electronic device body is preferably sealed with a sealing material. The sealing material can function as a protective member for the electronic device. There are no particular limitations on the sealing material, and any material commonly used as a sealing material for electronic devices may be used. Examples of sealing materials include, but are not limited to, ethylene-vinyl acetate copolymer (EVA), polyolefin elastomer, polyvinyl butyral, and ionomer, with EVA being preferred from the viewpoint of cost.

[0124] The protective sheet for an electronic device of the present invention is preferably directly bonded to an encapsulant from the viewpoint of reducing the thickness and improving the flexibility of the resulting electronic device, and from the viewpoint of simplifying the process of manufacturing the electronic device. When the protective sheet is bonded to an encapsulant that encapsulates the electronic device body, the protective sheet preferably includes a bonding resin layer that has high adhesion to the encapsulant. That is, it is preferable that the multilayer structure of the present invention and the encapsulant are directly laminated. In particular, when the encapsulant is made of an ethylene-vinyl acetate copolymer, it is preferable that an easy-adhesion layer (EA) is provided on the exposed surface of the multilayer structure of the present invention. The layers constituting the protective sheet may be bonded using a known adhesive or the adhesive layer described above.

[0125] FIG. 1 shows a partial cross-sectional view of an example of an electronic device of the present invention. The electronic device 40 of FIG. 1 includes an electronic device main body 41, a sealant 42 for sealing the electronic device main body 41, and a protective sheet (including a multilayer structure) 43 for protecting the surface of the electronic device main body 41. The sealant 42 covers the entire surface of the electronic device main body 41. The protective sheet 43 is disposed on one surface of the electronic device main body 41 via the sealant 42. A protective sheet may also be disposed on the surface opposite the surface on which the protective sheet 43 is disposed. In this case, the protective sheet disposed on the opposite surface may be the same as or different from the protective sheet 43. The protective sheet 43 may be disposed on the electronic device main body 41 via another member such as the sealant 42, or may be disposed directly on the surface of the electronic device main body 41.

[0126] The electronic device body 41 is not particularly limited, and examples thereof include photoelectric conversion devices such as solar cells; information display devices such as organic EL displays, liquid crystal displays, and electronic paper; and lighting devices such as organic EL light-emitting elements. The encapsulant 42 is an optional member that is added as appropriate depending on the type and application of the electronic device body 41. Examples of the encapsulant 42 include ethylene-vinyl acetate copolymer and polyvinyl butyral.

[0127] A preferred example of the electronic device main body 41 is a solar cell. Examples of solar cells include silicon-based solar cells, compound semiconductor solar cells, organic solar cells, and perovskite solar cells. Examples of silicon-based solar cells include single-crystal silicon solar cells, polycrystalline silicon solar cells, and amorphous silicon solar cells. Examples of compound semiconductor solar cells include III-V compound semiconductor solar cells, II-VI compound semiconductor solar cells, and multi-component compound semiconductor solar cells such as CIS and CIGS. Examples of organic solar cells include organic thin-film solar cells and dye-sensitized solar cells. Furthermore, the solar cell may be an integrated solar cell in which a plurality of unit cells are connected in series, or it may not be an integrated solar cell.

[0128] Depending on the type, the electronic device body 41 can be manufactured using a so-called roll-to-roll method. In the roll-to-roll method, a flexible substrate (e.g., a stainless steel substrate, a resin substrate, etc.) wound around a delivery roll is delivered, elements are formed on the substrate to manufacture the electronic device body 41, and the electronic device body 41 is then wound up around a take-up roll. In this case, the protective sheet 43 may also be prepared in the form of a flexible, long sheet, more specifically, in the form of a long, wound sheet. In one example, the protective sheet 43 delivered from the delivery roll is laminated on the electronic device body 41 before being wound up around the take-up roll, and then wound up together with the electronic device body 41. In another example, the electronic device body 41 wound up around the take-up roll may be delivered again from the roll and laminated with the protective sheet 43. In a preferred example of the present invention, the electronic device itself is flexible.

[0129] The protective sheet 43 includes the multilayer structure of the present invention. The protective sheet 43 may be composed of only the multilayer structure. Alternatively, the protective sheet 43 may include the multilayer structure and other members (e.g., other layer (J)) laminated on the multilayer structure. There are no particular limitations on the thickness or material of the protective sheet 43, as long as it is a layered laminate suitable for protecting the surface of an electronic device and includes the multilayer structure.

[0130] The configuration of the electronic device of the present invention is not particularly limited, but from the viewpoint of stable use as a flexible electronic device, the following configurations may be preferred. (1) Protective sheet / sealant / electronic device main body / sealant / protective sheet (2) Protective sheet / adhesive layer / sealant / electronic device main body / sealant / adhesive layer / protective sheet EVA is preferably used as the sealing material. Furthermore, the adhesive layer may be the same as the adhesive layer (I).

[0131] The present invention will now be described in more detail with reference to examples. The present invention is not limited to these examples, and many modifications can be made by those skilled in the art within the scope of the technical concept of the present invention. Analysis and evaluation in the following examples and comparative examples were carried out as follows.

[0132] <Materials used in the examples and comparative examples> Substrate (X) PET12: biaxially oriented polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumirror (trademark) P60" (product name), thickness 12 μm PET25: biaxially oriented polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumirror (trademark) S105" (product name), thickness 25 μm PET50: biaxially oriented polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumirror (trademark) U403" (product name), thickness 50 μm PET75: biaxially oriented polyethylene terephthalate film; manufactured by Toray Industries, Inc., "Lumirror (trademark) A48" ​​(product name), thickness 75 μm Adhesive layer (I) Two-component adhesive: "Takelac (registered trademark) A-520" manufactured by Mitsui Chemicals, Inc. and "Takenate (registered trademark) A-50" manufactured by Mitsui Chemicals, Inc. Blend ratio: "Takelac A-520" / "Takenate A-50" = 6 / 1. EVA200: ethylene-vinyl acetate copolymer film, vinyl acetate unit content 10.5 mol%, ethylene unit content 89.5 mol%, thickness 200 μm POE200: polyolefin elastomer, "Solar Ace (trademark)" manufactured by Mitsui Chemicals Tocello Co., Ltd., thickness 200 μm TPO200: thermal polyolefin, "PV-FS CVF (trademark)" manufactured by dnpSolar, thickness 200 μm PVB250: polyvinyl butyral film, "MOWITAL (trademark) Thin Film 250 (trademark)" manufactured by Kuraray Co., Ltd., thickness 250 μm Other layers ETFE25: ethylene-tetrafluoroethylene copolymer film, thickness 25 μm

[0133] <Evaluation Method> (1) Measurement of Infrared Absorption Spectrum The layer (Y) of the laminate obtained in the Examples and Comparative Examples was measured by an attenuated total reflection method using a Fourier transform infrared spectrophotometer. －１ ~1400cm －１ The maximum absorption wave number (Imax) in the region was calculated. The measurement conditions were as follows: Apparatus: Spectrum One manufactured by PerkinElmer Co., Ltd. Measurement mode: Attenuated total reflection method Measurement region: 800 cm －１ ~1400cm －１

[0134] (2) Thickness The multilayer structures obtained in the examples and comparative examples were cut using a focused ion beam (FIB) to prepare slices for cross-sectional observation. The prepared slices were fixed to a sample base with carbon tape and subjected to platinum ion sputtering at an acceleration voltage of 30 kV for 30 seconds. The cross section of the multilayer structure was observed using a field emission transmission electron microscope, and the thickness of each layer and the thickness of the multilayer structure as a whole were calculated. The measurement conditions were as follows: Apparatus: JEM-2100F manufactured by JEOL Ltd. Acceleration voltage: 200 kV Magnification: 250,000x

[0135] (3) Total Light Transmittance and Haze The multilayer structures obtained in the Examples and Comparative Examples were attached to a haze meter HR-100 (manufactured by Murakami Color Research Laboratory Co., Ltd.), and the total light transmittance was measured in accordance with JIS K 7361-1:1997, and the haze was measured in accordance with JIS K 7136:2000. The measurement was performed five times, and the average value was taken as the measured value. When the multilayer structure had an asymmetric configuration, the multilayer structure was attached so that the layer (Y) was the shortest with respect to the incident light. For example, in the multilayer structure of Example 9, the multilayer structure was attached so that the surface on which the layer (Y) was exposed faced the incident light side.

[0136] (4) Moisture Permeability (Water Vapor Barrier Property) The multilayer structures obtained in the Examples and Comparative Examples were attached to a water vapor transmission rate measuring device, and the moisture permeability (water vapor permeability) was measured by a differential pressure method in accordance with ISO 15106-5. The measurement conditions were as follows: ２-day), it was determined that the moisture permeability was insufficient. Note that when the layer (Y) was exposed, the measurement was performed after laminating PET12 to prevent damage to the layer (Y) when it was attached to the apparatus or during decompression, which would prevent accurate measurement of the moisture permeability. The lamination method was as follows. <Lamination method> A two-component adhesive ("A-520" (brand) of "Takelac" (registered trademark) manufactured by Mitsui Chemicals, Inc. and "A-50" (brand) of "Takenate" (registered trademark) manufactured by Mitsui Chemicals, Inc.) was applied to PET12 using a bar coater so that the thickness of the adhesive layer after drying would be 3 μm, and this was laminated with the exposed layer (Y) of the multilayer structure obtained in the Examples and Comparative Examples, and allowed to stand at 40° C. for 5 days for aging. <Moisture permeability measurement conditions> Apparatus: DELTAPERM manufactured by TECHNOLOX Temperature: 40° C. Humidity on water vapor supply side: 90% RH

[0137] (5) Roll formability (flexibility) The multilayer structures obtained in the examples and comparative examples were cut into a length (MD direction) of 29.7 cm and a width (TD direction) of 21 cm, rolled in the lengthwise direction to form a roll with a diameter of 2 cm, and then a rubber band (O-Band #16 manufactured by Kyowa Co., Ltd.) with an inner diameter of 38 cm, a thickness of 1.1 mm, and a cut width of 1.1 mm was placed in the center of the roll. The rolling force was then released, and the roll shape was maintained only by the rubber band. Subsequently, the diameters at both ends were measured. This measurement was performed five times, and the average value of a total of 10 points was calculated. A value of less than 4.2 cm was rated A, a value that expanded from 4.2 cm to less than 4.5 cm was rated B, and a value that expanded to 4.5 cm or more was rated C. Those rated C were judged to have insufficient flexibility.

[0138] (6) Flex Resistance The multilayer structures obtained in the Examples and Comparative Examples were cut to 210 mm x 297 mm (A4 size) and subjected to 10 cycles of flexing using a Gelbo Flex Tester (manufactured by Rigaku Kogyo Co., Ltd.) in accordance with ASTM F-392. Of the flexed multilayer structures, those in which no delamination occurred were rated A, those in which the maximum length of the area in which delamination occurred was less than 3 mm were rated B, and those in which the maximum length of the area in which delamination occurred was 3 mm or more were rated C. Those rated B or C were determined to have insufficient flex resistance.

[0139] <Production Example of Coating Liquid (S-1)> 230 parts by mass of distilled water was heated to 70°C while stirring. 88 parts by mass of triisopropoxyaluminum was added dropwise to the distilled water over 1 hour, and the liquid temperature was gradually raised to 95°C. Hydrolysis and condensation were carried out by distilling off the generated isopropanol. 4.0 parts by mass of a 60% by mass aqueous nitric acid solution was added to the resulting liquid, and the mixture was stirred at 95°C for 3 hours to deflocculate the particle aggregates of the hydrolysis and condensation product. The liquid was then concentrated to a solids concentration of 10% by mass in terms of aluminum oxide, yielding a solution. 54.29 parts by mass of distilled water and 18.80 parts by mass of methanol were added to 22.50 parts by mass of the resulting solution, and the mixture was stirred until uniform, yielding a dispersion. Subsequently, 4.41 parts by mass of an 85% by mass aqueous phosphoric acid solution was added dropwise to the dispersion while stirring, while maintaining the liquid temperature at 15°C. Further, 18.80 parts by mass of the methanol solution was added dropwise, and stirring was continued at 15°C until the viscosity reached 1,500 mPa s, to obtain the target coating solution (S-1). The molar ratio of aluminum atoms to phosphorus atoms in the coating solution (S-1) was aluminum atoms:phosphorus atoms = 1.15:1.00.

[0140] <Production Example of Coating Liquid (R-1)> 4.8 parts by mass of PVA "Kuraray Poval (registered trademark) 48-80" and 95.2 parts by mass of water were mixed and stirred at room temperature for 5 hours to dissolve the "Kuraray Poval (registered trademark) 48-80" and obtain a PVA aqueous solution. Next, 0.8 parts by mass of polyester-based aqueous dispersion "Elitell (registered trademark) KA-5071S" (manufactured by Unitika Ltd.), 1.2 parts by mass of the above PVA aqueous solution, 68.1 parts by mass of water, and 29.9 parts by mass of methanol were mixed and stirred for 1 hour to obtain coating liquid (R-1).

[0141] <Production Example of Aluminum Oxide Vapor-Deposited Film> PET12 was used as the substrate (X), and deposition was carried out using an electron beam heating vacuum deposition apparatus and metallic aluminum under the introduction of oxygen gas, to form an inorganic oxide layer made of aluminum oxide and having a thickness of 20 nm on the substrate (X).

[0142] <Example of manufacturing silicon oxynitride sputtering film> PET25 was used as the substrate (X) and set in the chamber of a batch sputtering device. Then, silicon nitride having a sintering density of 60% was set in the chamber as a target material. At the same time, the distance between the target and the substrate (X) was set to 50 mm. The chamber was vacuumed to a degree of 5.0 × 10 ―４ After the pressure was reduced to 1 Pa, oxygen gas and argon gas were introduced into the chamber, and a layer of silicon oxynitride having a thickness of 80 nm was formed on the substrate (X) by RF magnetron sputtering.

[0143] Example 1 PET25 was used as the substrate (X), and a corona treatment device TEC-4AC manufactured by Kasuga Electric Co., Ltd. was used to treat the substrate at 130 W·min / m ２ A surface treatment was performed on one side of the substrate (X) at a strength of 1000 kJ / cm. The coating liquid (R-1) was applied using a bar coater to one side of the surface-treated substrate so that the thickness after drying would be 10 nm. The coated film was dried at 140 ° C. for 1 minute to form an adhesive layer (AC) on one side of the substrate. The coating liquid (S-1) was applied using a bar coater to one side of the substrate on which the adhesive layer (AC) was formed so that the average thickness after drying would be 0.4 μm. The coated film was dried at 120 ° C. for 3 minutes and then heat-treated at 180 ° C. for 1 minute to form a precursor layer of the layer (Y) on the substrate. Next, the other side was also surface-treated by the same method, and then an adhesive layer (AC) and a precursor layer of the layer (Y) were formed. The film on which the precursor layer of the layer (Y) was formed was heat-treated at 210 ° C. for 1 minute to obtain a laminate (1) of layer (Y) (0.4 μm) / adhesive layer (AC) (10 nm) / substrate (X) (25 μm) / adhesive layer (AC) (10 nm) / layer (Y) (0.4 μm). The infrared absorption spectrum of the layer (Y) of the obtained laminate (1) was measured according to the method described in the above evaluation method (1), and the 800 cm －１ ~1400cm －１ The maximum absorption wave number (Imax) in the region was evaluated. The maximum absorption wave number (Imax) was 1108 cm on both sides. －１ The results are shown in Table 1.

[0144] A two-component adhesive ("Takelac" (registered trademark) "A-520" (brand) and "Takenate" (registered trademark) "A-50" (brand) manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the laminate (1) using a bar coater so that the thickness after drying was 3 μm, and the adhesive layer (I) was formed by drying at 70 ° C. for 8 minutes. Another laminate (1) was laminated on the adhesive layer (I), and the resultant was left standing at 23 ° C. for 10 days (aging condition 1), and then left standing at 40 ° C. for 4 days for aging (aging condition 2). A multilayer structure having the structure laminate (1) / adhesive layer (I) / laminate (1) = Y / / PET25 / / Y / I / Y / / PET25 / / Y (" / / " in the examples refers to the adhesive layer (AC)) was obtained. The resulting multilayer structure was evaluated according to the methods described in the above evaluation methods (2) to (6). The results are shown in Table 1.

[0145] Examples 2 to 4, Comparative Example 1 Laminates and multilayer structures were produced and evaluated in the same manner as in Example 1, except that the type of substrate (X) and the conditions for forming the adhesive layer (I) were changed as shown in Table 1. The results are shown in Table 1.

[0146] Example 5 The laminate (1) prepared in Example 1 and EVA200 were vacuum laminated under the following conditions to obtain a multilayer structure having a structure of laminate (1) / EVA200 / laminate (1). (Vacuum lamination conditions) Vacuum laminating device: 1522N manufactured by Nisshinbo Mechatronics Inc. Vacuuming time: 8 minutes Temperature: 160°C Time: 30 minutes Pressure: 30 kPa

[0147] The obtained multilayer structure was evaluated according to the above evaluation methods (2) to (6). The results are shown in Table 1.

[0148] Examples 6 to 8 Laminates and multilayer structures were produced and evaluated in the same manner as in Example 5, except that the type of adhesive layer (I) was changed according to Table 1.

[0149] Example 9: PET12 was used as the substrate (X), and a corona treatment device TEC-4AC manufactured by Kasuga Electric Co., Ltd. was used to treat the substrate (X) at 130 W·min / m ２One surface of the substrate (X) was subjected to a surface treatment with a strength of 100000000000000. The coating liquid (R-1) was applied to one surface of the surface-treated substrate using a bar coater so that the thickness after drying would be 10 nm. The coated film was dried at 140 ° C. for 1 minute to form an adhesive layer (AC) on one side of the substrate. The coating liquid (S-1) was applied to one surface of the substrate on which the adhesive layer (AC) was formed using a bar coater so that the average thickness after drying would be 0.4 μm. The coated film was dried at 120 ° C. for 3 minutes and then heat-treated at 180 ° C. for 1 minute to form a precursor layer of layer (Y) on the substrate. The resulting film on which the precursor layer of layer (Y) was formed was heat-treated at 210 ° C. for 1 minute to obtain a laminate (2) of substrate (X) (12 μm) / adhesive layer (AC) (10 nm) / layer (Y) (0.4 μm). The infrared absorption spectrum of the layer (Y) of the obtained laminate (2) was measured according to the method described in the evaluation method (1) above. －１ ~1400cm －１ The maximum absorption wavenumber (Imax) in the region was evaluated. The maximum absorption wavenumber (Imax) was 1108 cm －１ It was.

[0150] A two-component adhesive ("Takelac" (registered trademark) "A-520" (brand) and "Takenate" (registered trademark) "A-50" (brand) manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the laminate (1) prepared in Example 1 using a bar coater so that the thickness after drying was 3 μm, and the adhesive layer (I) was formed by drying at 70 ° C. for 8 minutes. The laminate (2) was laminated on the adhesive layer (I), and the laminate was allowed to stand at 23 ° C. for 10 days, and then allowed to stand at 40 ° C. for 4 days for aging, to obtain a multilayer structure having a structure of laminate (1) / adhesive layer (I) / laminate (2) = Y / / PET25 / / Y / I / Y / / PET12. The obtained multilayer structure was evaluated according to the methods described in the above evaluation methods (2) to (6). The results are shown in Table 1.

[0151] Example 10 A laminate (layer (Y) (0.4 μm) / substrate (X) (25 μm) / layer (Y) (0.4 μm)) and a multilayer structure were produced and evaluated in the same manner as in Example 1, except that the adhesive layer (AC) was not formed. The results are shown in Table 1.

[0152] Examples 11 to 13 Laminates and multilayer structures were produced and evaluated in the same manner as in Example 1, except that the type of one of the two laminates (1) was changed according to Table 1.

[0153] Comparative Example 2 A two-component adhesive ("Takelac" (registered trademark) "A-520" (brand) and "Takenate" (registered trademark) "A-50" (brand) manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the laminate (2) produced in Example 9 using a bar coater so that the thickness after drying would be 3 μm, and the adhesive layer (I) was formed by drying at 70° C. for 8 minutes. Another laminate (2) was laminated on the adhesive layer (I), to obtain a laminate (2) / adhesive layer (I) / laminate (2)=PET12 / / Y / I / Y / / PET12 structure (2-1). Further, using a similar method, a two-component adhesive ("Takelac" (registered trademark) manufactured by Mitsui Chemicals, Inc., brand "A-520" and "Takenate" (registered trademark) manufactured by Mitsui Chemicals, Inc., brand "A-50") was applied to the surface of the laminate (2) using a bar coater so that the thickness after drying would be 3 μm, and dried at 70° C. for 8 minutes to form an adhesive layer (I), which was then laminated with the laminate (2-1). A laminate (2-2) having a structure of laminate (2) / adhesive layer (I) / laminate (2) / adhesive layer (I) / laminate (2)=PET12 / / Y / I / Y / / PET12 / I / PET12 / / Y was obtained. The same procedure was repeated to laminate the laminate (2-2) and the laminate (2), and the resulting mixture was left at 23°C for 10 days and then left at 40°C for 4 days for aging, yielding a multilayer structure having the following structure: laminate (2) / adhesive layer (I) / laminate (2) / adhesive layer (I) / laminate (2) / adhesive layer (I) / laminate (2)=PET12 / / Y / I / Y / / PET12 / I / PET12 / / Y / I / Y / / PET12. The resulting multilayer structure was evaluated according to the methods described in the above evaluation methods (2) to (6). The results are shown in Table 1.

[0154] Comparative Example 3 A laminate and a multilayer structure were produced and evaluated in the same manner as in Example 5, except that laminate (2) was used and the layer configuration was changed as shown in Table 1 to produce a multilayer structure of laminate (2) / I / laminate (2) / I / laminate (2) / I / laminate (2)=PET12 / / Y / I / Y / / PET12 / I / PET12 / / Y / I / Y / / PET12. The results are shown in Table 1.

[0155] Comparative Example 4 A two-component adhesive ("Takelac" (registered trademark) "A-520" (brand) and "Takenate" (registered trademark) "A-50" (brand) manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the laminate (2) produced in Example 9 using a bar coater so that the thickness after drying would be 3 μm, and the adhesive layer (I) was formed by drying at 70 ° C. for 8 minutes. Another laminate (2) was laminated on the adhesive layer (I), and a laminate (2-1) having a structure of laminate (2) / adhesive layer (I) / laminate (2) = PET12 / / Y / I / Y / / PET12 was obtained. Further, using a similar method, a two-component adhesive ("Takelac" (registered trademark) "A-520" (brand) manufactured by Mitsui Chemicals, Inc. and "Takenate" (registered trademark) "A-50" (brand) manufactured by Mitsui Chemicals, Inc.) was applied to the surface of the laminate (2) using a bar coater so that the thickness after drying would be 3 μm, and dried at 70 ° C. for 8 minutes to form an adhesive layer (I), which was then laminated with the laminate (2-1). A multilayer structure having a structure of laminate (2) / adhesive layer (I) / laminate (2) / adhesive layer (I) / laminate (2) = PET12 / / Y / I / Y / / PET12 / I / PET12 / / Y was obtained. The obtained multilayer structure was evaluated according to the methods described in the above evaluation methods (2) to (6). The results are shown in Table 1.

[0156]

[0157] Example 11 A solar cell having a configuration of ETFE25 / EVA200 / multilayer structure / EVA200 / CIGS solar cell / EVA200 / multilayer structure was produced by vacuum laminating the multilayer structure produced in Example 1, EVA200, ETFE25, and a CIGS solar cell under the conditions described in Example 5. The photoelectric conversion efficiency of the obtained solar cell was measured before and after storage for 1000 hours in an atmosphere of 85°C and 85% RH, and the decrease rate was less than 10%.

[0158] Example 12 A solar cell was produced in the same manner as in Example 11, except that EVA 200 was changed to POE 200. The photoelectric conversion efficiency of the obtained solar cell was measured before and after storage for 1000 hours in an atmosphere of 85°C and 85% RH, and the decrease in efficiency was found to be less than 10%.

[0159] Example 13 A solar cell was produced in the same manner as in Example 11, except that EVA 200 was changed to TPO 200. The photoelectric conversion efficiency of the obtained solar cell was measured before and after storage for 1000 hours in an atmosphere of 85°C and 85% RH, and the decrease in efficiency was found to be less than 10%.

[0160] Example 14 A solar cell was produced in the same manner as in Example 11, except that EVA 200 was changed to PVB 250. The photoelectric conversion efficiency of the obtained solar cell was measured before and after storage for 1000 hours in an atmosphere of 85°C and 85% RH, and the decrease in efficiency was found to be less than 10%.

[0161] Example 15 A solar cell having a configuration of ETFE25 / EVA200 / multilayer structure / EVA200 / CIGS solar cell / EVA200 / multilayer structure was produced by vacuum laminating the multilayer structure produced in Example 1, EVA200, ETFE25, and a perovskite solar cell under the conditions described in Example 5. The photoelectric conversion efficiency of the obtained solar cell was measured before and after storage for 1000 hours in an atmosphere of 85°C and 85% RH, and the decrease was less than 10%.

[0162] 40 Electronic device 41 Electronic device body 42 Sealant 43 Protective sheet

Claims

1. A laminate (α) including a substrate (X) and a layer (Y), and a laminate (β) including the substrate (X) and a layer (Y'), wherein the layer (Y) includes a reaction product (D) of a metal oxide (A) including an aluminum atom and an inorganic phosphorus compound (B), and the layer (Y') includes at least one selected from the group consisting of a metal oxide, a metal nitride, a metal nitride oxide, a metal carbonitride, and the reaction product (D), the laminate (α) and the laminate (β) are laminated via an adhesive layer (I), and the laminate (α) and the laminate (β) have a total light transmittance of 87% or more as measured in accordance with JIS K 7361-1:1997 and a moisture permeability of 2.0×10 or more as measured in accordance with ISO 15106-5. －３ g / m ２ - A multi-layer structure having a thickness of 0.1 - 0.25 mm.

2. The multilayer structure according to claim 1, comprising at least two laminates each including a substrate (X) and a layer (Y).

3. The multilayer structure according to claim 1 or 2, which has a haze value of 7% or less as measured in accordance with JIS K 7136:2000.

4. The multilayer structure according to claim 1 or 2, wherein at least one of the laminates has a configuration in which a layer (Y) is disposed on both sides of a substrate (X).

5. The multilayer structure according to claim 1 or 2, wherein the thickness of one layer of the substrate (X) is 100 μm or less.

6. The multilayer structure according to claim 1 or 2, wherein the adhesive layer (I) contains at least one adhesive material selected from the group consisting of polyurethane, polyester, acrylic resin, epoxy resin, polyolefin elastomer, ethylene-vinyl acetate copolymer, polyvinyl butyral and ionomer.

7. The multilayer structure according to claim 1 or 2, which is laminated by dry lamination or vacuum lamination.

8. The multilayer structure according to claim 1 or 2, wherein the adhesive layer (I) is a layer provided by a two-component adhesive.

9. In the infrared absorption spectrum of layer (Y), －１ ~1400cm －１ The maximum absorption wavenumber in the region is 1080 cm －１ ~1130cm －１ 3. The multilayer structure according to claim 1 or 2, wherein the thickness of said multilayer structure is in the range of 10. The multilayer structure according to claim 1 or 2, wherein the substrate (X) and the layer (Y) are laminated via an adhesive layer (AC).

11. A method for producing a laminate comprising the steps of: applying a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (BI), and a solvent to a substrate (X), and removing the solvent to form a precursor layer of a layer (Y); heat-treating the precursor layer of the layer (Y) to form a layer (Y); and laminating at least one of the laminates obtained through the step (II) via an adhesive layer (I); wherein in the step (III), a two-component adhesive is applied to the surface of one of the laminates, the solvent is removed, and an aging step (III-AII) is performed after laminating the laminates via the adhesive layer (I); wherein the drying temperature in the step (III-AI) is 45°C or higher and 150°C or lower; The method for producing a multilayer structure according to claim 8, wherein the aging conditions in step (III-AII) include condition 1 of aging at a temperature of 10° C. or higher and lower than 35° C. for 1 day or more and 30 days or less, and condition 2 of aging at a temperature of 35° C. or higher and 70° C. or lower for 1 day or more and 30 days or less.

12. A protective sheet for an electronic device comprising the multilayer structure according to claim 1 or 2.

13. The protective sheet according to claim 12, which is a protective sheet for protecting the surface of a photoelectric conversion device, an information display device, or a lighting device.

14. An electronic device having the protective sheet according to claim 12.

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