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

[Technical Field]

[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. [Background technology]

[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] A protective sheet that can replace a glass plate needs to have excellent barrier properties, particularly excellent water vapor barrier properties. Patent Document 1, for example, 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 average particle size of the reaction product is 5 nm to 70 nm. It has excellent gas barrier properties and water vapor barrier properties, and can be used as a protective sheet that can maintain its performance even after a dump heat test.

[0004] [Patent Document 1] International Publication No. 2016 / 103720 Summary of the Invention [Problem to be solved by the invention]

[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. [Means for solving the problem]

[0007] That is, the present invention [1] 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 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 laminate (α) and the laminate (β) are laminated via an adhesive layer (I), and the laminate 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 ISO15106-5. -3 g / m 2 · Day or less, multi-layer structure; [2] The multilayer structure according to [1], which comprises at least two laminates each including a substrate (X) and a layer (Y); [3] The multilayer structure of [1] or [2], having a haze value of 7% or less as measured in accordance with JIS K 7136:2000; [4] The multilayer structure of any one of [1] to [3], 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 of any one of [1] to [4], wherein the thickness of one layer of the substrate (X) is 100 μm or less; [6] The multilayer structure of any one of [1] to [5], 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] A multilayer structure according to any one of [1] to [6], laminated by dry lamination or vacuum lamination; [8] The multilayer structure of 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 wavenumber in the region is 1080 cm -1 ~1130cm -1 A multilayer structure of any of [1] to [8] in the range of

[10] The multilayer structure according to any one of [1] to [9], wherein the substrate (X) and the layer (Y) are laminated via the adhesive layer (AC);

[11] A method for manufacturing a laminated laminate, 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 a 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 an 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 ( a step (III-AI) of forming an adhesive layer (I) on the laminate, and a step (III-AII) of laminating the laminate via the adhesive layer (I) and then aging the laminate, wherein the drying temperature in the step (III-AI) is 45°C or higher and 150°C or lower, and the aging conditions in the step (III-AII) include condition 1 of aging at a temperature of 10°C or higher but lower than 35°C for 1 day or longer and 30 days or shorter, and condition 2 of aging at a temperature of 35°C or higher but 70°C or lower for 1 day or longer and 30 days or shorter;

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

[12] or

[13] ; This is achieved by providing [Effects of the Invention]

[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. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an electronic device of the present invention. DETAILED DESCRIPTION OF THE 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 high total light transmittance measured in accordance with JIS K 7361-1:1997 and 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 indicated using "to" include the numerical values ​​before and after "to" as the lower and upper limits. In other words, "a to b" means "a to b." 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) 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 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 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 1 / 2 days 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] [Base material (X)] The substrate (X) is not particularly limited, and various substrates can be used. The material of the substrate (X) is not particularly limited, but 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, but it is preferably in the form of a layer such as a film or a 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 contains a thermoplastic resin film, and even more preferably is 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; and ionomer resins. 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 deposition layer (X') used as the substrate (X) is usually a film that has barrier properties against oxygen and water vapor, and is preferably a transparent film. The thermoplastic resin film used for the thermoplastic resin film laminated with an inorganic vapor deposition layer (X') can be any of the thermoplastic resin films exemplified above as the substrate (X). The inorganic vapor deposition 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 deposition 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 type 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 to 200 μm, more preferably 7 μm to 100 μm, and even more preferably 10 μm to 80 μm. 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 containing aluminum atoms (A)] 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 also 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 in Group 2 of the periodic table, such as magnesium and calcium; metals in Group 12 of the periodic table, such as zinc; metals in Group 13 of the periodic table; metals in Group 14 of the periodic table, such as silicon; and transition metals, such as titanium and zirconium. Silicon is sometimes classified as a metalloid, but in this specification, silicon is included in the category of metals. 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) bonded to a hydrolyzable characteristic group. Examples of the characteristic group include a halogen atom, NO, 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, or 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, the term "metal oxide (A)" can be read as "hydrolysis condensation product of compound (E)", and the term "hydrolysis condensation product of compound (E)" can be read as "metal oxide (A)".

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

[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, and tri-tert-butoxyaluminum, 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. 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] When compound (E) is hydrolyzed, at least a portion of the hydrolyzable characteristic groups of compound (E) is converted to hydroxyl groups. Furthermore, the hydrolyzate undergoes condensation 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 essentially be considered a metal oxide. Hydroxyl groups are usually present on the surface of the metal oxide (A) thus formed.

[0029] In this specification, compounds having a ratio of [the number of moles of oxygen atoms (O) bonded only to metal atoms (M)] / [the number of moles of metal atoms (M)] of 0.8 or more are considered to be metal oxides (A). Here, the oxygen atoms (O) bonded only to metal atoms (M) are oxygen atoms (O) in a structure represented by MOM, and exclude oxygen atoms bonded to a metal atom (M) and a hydrogen atom (H), such as oxygen atoms (O) in a structure represented by MOH. The above ratio in metal oxides (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 may 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 (an inorganic phosphorus compound (BI) or a composition containing an inorganic phosphorus compound (BI)) described below contains substantially no phosphorus atoms.

[0033] [Inorganic phosphorus compounds (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), such as 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 inorganic phosphorus compounds (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) and dehydrates (e.g., diphosphorus pentoxide)). These compounds may be used alone or in combination. Among these, from the viewpoints 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 MOP 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 MOP bond is at 1080 cm -1 ~1130cm -1 In particular, when the characteristic absorption band is observed in the 800 cm region, where absorption due to the bonding of various atoms with oxygen atoms is generally observed, the obtained multilayer structure exhibits excellent gas barrier properties. -1~1400cm -1 In other words, the multilayer structure of the present invention exhibits even more excellent gas barrier properties when the layer (Y) has the strongest absorption in the 800 cm region in the infrared absorption spectrum. -1 ~1400cm -1 The maximum absorption wavenumber in the region is 1080 cm -1 ~1130cm -1 The moisture permeability measured in accordance with ISO15106-5 is 1.0 x 10 -2 g / m 2 It tends to be easier to adjust to less than 10 days.

[0037] In contrast, when a metal compound such as compound (E) or a metal salt is mixed with an inorganic phosphorus compound (BI) in advance and then hydrolysis and condensation are carried out, a complex is obtained in which the metal atoms derived from the metal compound and the 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 wavenumber 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 this region is set to 200 cm from the viewpoint of the gas barrier properties of the resulting multilayer structure. -1 Less than 150cm is preferable -1 Less than 100cm is preferable. -1 Less than 50cm is more preferable -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, if the measurement cannot be performed by the above method, it may be performed by a reflection measurement method such as a reflection absorption method, an external reflection method, or an attenuated total reflection method, or by a transmission measurement method such as a Nujol method or a tablet method after scraping off the layer (Y) from the multilayer structure, but the 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 compounds (BO)] The organic phosphorus compound (BO) is preferably a polymer (BOa) or an organic phosphorus compound (BOb) having a plurality of phosphorus atoms.

[0044] [Polymer containing multiple phosphorus atoms (BOa)] Examples of the phosphorus atom-containing functional group contained in the polymer (BOa) include a phosphate group, a phosphite group, a phosphonate group, a phosphonite group, a phosphinate group, a phosphinite group, and functional groups derived therefrom (for example, salts, (partial) ester compounds, halides (for example, chlorides), dehydrates), etc. 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)acrylates 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-containing functional group, or a copolymer of two or more monomers. Two or more polymers composed of a single monomer may also be used 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-containing functional group and another vinyl monomer. Examples of other vinyl monomers copolymerizable with the monomer having a phosphorus-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. Of these, (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 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 using a coating liquid (S) described below, viscosity stability of the coating liquid (S).

[0049] When layer (Y) of the multilayer structure contains a polymer (BOa), the ratio WBOa / WBI of the mass of inorganic phosphorus compound (BI) to the mass of polymer (BOa) in layer (Y) preferably satisfies the relationship 0.01 / 99.99≦WBOa / WBI<6.00 / 94.00. 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, still more preferable that it satisfies the relationship 0.20 / 99.80≦WBOa / WBI<4.00 / 96.00, and particularly preferable that it satisfies the relationship 0.50 / 99.50≦WBOa / WBI<3.50 / 96.50. That is, it is preferable that WBOa is used in a very small amount of 0.01 or more and less than 6.00, while WBI is used in a large amount of more than 94.00 and not more than 99.99. Even when inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa) are reacted in layer (Y), the inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa) constituting reaction product (D) are considered to be inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa). In this case, the mass of inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa) used to form reaction product (D) (the mass of inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa) before reaction) is included in the mass of inorganic phosphorus compounds (BI) and / or organic phosphorus compounds (BOa) in layer (Y).

[0050] [Organophosphorus compounds (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 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 toward the surface 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 is 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 measured by X-ray photoelectron spectroscopy (XPS) at a depth of 5 nm from the surface on the side not in contact with substrate (X) 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 flexibility of the multilayer structure is increased, so that its mechanical properties can be made closer to 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)] The 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 the layer (Y) contains the 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, and may be 5% by mass or less, 2% by mass or less, or 0% by mass, based on the mass of layer (Y). Polymer (F) may or may not react with components in layer (Y).

[0060] Layer (Y) may further contain other components. Examples of other components that can be contained in layer (Y) include inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, bicarbonates, 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; polymeric compounds other than polymer (BOa) and polymer (F); plasticizers; antioxidants; ultraviolet absorbers; and flame retardants. The content of the above other components in 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. It may be 3% by mass or less, 1% by mass or less, or 0% by mass (no other components included).

[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) laminated directly on the surface of the layer (Y) opposite the substrate (X). The inclusion of the layer (W) may improve flex resistance and 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 inclusion 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 with 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] Layer (W) may further contain other components. Examples of other components include inorganic acid metal salts such as carbonates, hydrochlorides, nitrates, bicarbonates, sulfates, hydrogen sulfates, 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; polymeric compounds other than polymer (BOa) and polymer (F); plasticizers; antioxidants; ultraviolet absorbers; and flame retardants. The content of the other components in 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 a 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 there are no particular limitations on the upper limit of the thickness of the layer (W), 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 inorganic materials 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 type 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 can 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 adhesiveness 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] [Laminated body (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 the laminate, the layer (W) may be laminated directly on the exposed surface of the layer (Y). Providing the layer (W) on the exposed surface of the layer (Y) or layer (Y') may improve the flex resistance of the multilayer structure of the present invention and may improve 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 multiple layers. Here, " / " means that the layers are directly laminated, and " / / " means that the layers are directly laminated or laminated via an adhesive layer (AC). (1) Base material (X) / / Layer (Y) (2) Base material (X) / / layer (Y) / layer (W) (3) Layer (Y) / / Base material (X) / / Layer (Y) (4) Layer (Y) / / Base material (X) / / Layer (Y) / Layer (W) (5) Layer (W) / Layer (Y) / / Substrate (X) / / Layer (Y) / Layer (W)

[0073] [Laminated body (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 has 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 have a layer (W) directly laminated on the exposed surface side of the layer (Y'). Providing the layer (W) on the exposed surface side of the layer (Y') may improve the flex resistance of the multilayer structure of the present invention and the adhesion to the adhesive layer (I) described below. 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 multiple layers. Here, " / " means that the layers are directly laminated, and " / / " means that the layers are directly laminated or laminated via an adhesive layer (AC). (1) Base material (X) / / Layer (Y') (2) Base material (X) / / layer (Y') / layer (W) (3) Layer (Y') / / Base material (X) / / Layer (Y') (4) Layer (Y') / / Base material (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 formed using 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 dry lamination 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 dry lamination.

[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 or light, 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, urethane adhesives, ester adhesives, acrylic adhesives, etc. can be used. Among these, urethane adhesives and polyester adhesives are preferred, and two-component reactive polyurethane adhesives in which a polyisocyanate component and a polyol component are mixed and reacted are 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 formed by vacuum lamination, the material used for the adhesive layer (I) may be any transparent material with strong adhesive strength, such as one that melts and hardens when heated. Materials commonly used as encapsulants for solar cells and the like are particularly suitable. For example, the adhesive layer (I) preferably contains at least one material 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. However, the thickness tends to be thicker than that of dry lamination, which may result in reduced flexibility.

[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 laminates, 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. A thickness of 20 μm or more tends to improve mechanical strength and processability during production of the multilayer structure. Furthermore, a thickness of 1000 μm or less tends to improve flexibility of the multilayer structure.

[0084] The moisture permeability of the multilayer structure of the present invention measured at 40°C and 90% RH was 2.0 × 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 ISO15106-5:2015. The moisture permeability is preferably 1.0×10 -6 g / m 2 ·day or more, 5.0 × 10 -5 g / m 2 ·day or more, 1.0 × 10 -4 g / m 2 The moisture permeability may be 2.0×10-3 g / m 2 1 day or less, for example, by providing two or more of the above laminates, -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] [Multi-layer 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 structure of the multilayer structure of the present invention are shown below, but each example may be combined in multiple configurations. " / " means that the laminates 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 of manufacturing a multilayer structure] The matters described for the multilayer structure of the present invention are applicable to the manufacturing method of the present invention, and therefore, redundant explanations may be omitted. Furthermore, the matters described for the manufacturing 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 includes, for example, the steps of: applying a coating liquid (S) containing a metal oxide (A), an inorganic phosphorus compound (B1), and a solvent to a substrate (X) and removing the solvent to form a precursor layer of layer (Y); heat-treating the precursor layer of layer (Y) to form layer (Y); and laminating at least two laminates obtained through step (II) via an adhesive layer (I). When producing a multilayer structure containing an organic phosphorus compound (B1) or a polymer (F), the coating liquid (S) used in step (I) may contain the organic phosphorus compound (B1) or the polymer (F), or the method may include a step (IV) of preparing a coating liquid (T) containing the organic phosphorus compound (B1) or the polymer (F) and applying it to the surface of the precursor layer of layer (Y) obtained in step (I) or to the surface of layer (Y) obtained in step (II). When an adhesive layer (AC) is provided between the substrate (X) and the layer (Y), the step (I) may be preceded by a step of providing the adhesive layer (AC) on the substrate (X).

[0091] [Process (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 methods for preparing the coating liquid (S) include mixing a dispersion of the metal oxide (A) with a solution containing the inorganic phosphorus compound (BI); or adding the inorganic phosphorus compound (BI) to a dispersion of the metal oxide (A) and mixing them. 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 optionally contain at least one acid compound (Q) selected from the group consisting of acetic acid, hydrochloric acid, nitric acid, trifluoroacetic acid, and trichloroacetic acid.

[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 mixture 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 for 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 application is preferably 3000 mPa·s or less, more preferably 2500 mPa·s or less, and even more preferably 2000 mPa·s or less. 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. The viscosity of the coating liquid (S) is also 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, such as 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 to less than 140°C, even more preferably 70°C to less than 130°C, and particularly preferably 80°C to less than 120°C. The drying time is not particularly limited, but is preferably 1 second to less than 1 hour, more preferably 5 seconds to less than 15 minutes, and even more preferably 5 seconds to less 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 to less than 4 minutes, more preferably 5 seconds to less than 4 minutes, and even more preferably 5 seconds to less 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 to less than 1 hour, more preferably 6 minutes to less than 30 minutes, and even more preferably 8 minutes to less 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 laminating layers (Y) 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)). Then, a 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. Precursor layers for two layers (Y) may be formed simultaneously by applying the coating liquid (S) to both sides of the substrate (X) at the same time and removing the solvent.

[0102] [Process (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 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 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 steps, 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 carried out 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] [Process (III)] In step (III), at least two of the laminates obtained in step (II) are laminated via an adhesive layer (I). Laminating at least two laminates via an adhesive layer (I) can be performed by a known method. For example, a two-component adhesive is applied to the laminate, the solvent is removed to form an adhesive layer (I), and then the laminate is laminated by a known method; an adhesive film (e.g., a sealant) is used as the adhesive layer (I), and the adhesive layer is laminated on the laminate by vacuum lamination; etc.

[0107] When a two-component adhesive is used in step (III), the method includes a step (III-AI) of applying the 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 laminating the laminates via the adhesive layer (I) and then aging the laminates (III-AII), 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 but lower than 70°C for 2 days to 30 days. When laminating laminates 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. A drying temperature of 45°C or higher increases the drying rate of the solvent, tending to suppress deterioration of appearance due to residual solvent. Furthermore, a drying temperature of 150°C or lower tends to suppress dimensional changes during drying. 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. Controlling the drying time within the above range tends to suppress deterioration of appearance due to residual solvent and improve production efficiency. 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 for the first stage (condition 1) is preferably 1 to 30 days, more preferably 3 to 25 days, and even more preferably 5 to 20 days. By controlling the aging temperature and time for the first stage within the above ranges, the adhesive curing reaction can proceed slowly, which tends to both suppress deterioration of appearance due to gas generation during the curing reaction and improve production efficiency. The temperature for the second stage (condition 2) is preferably 35°C to 70°C, more preferably 36°C to 65°C, and even more preferably 37°C to 60°C.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, which tends to achieve both improved adhesion and improved production efficiency.

[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 vacuum lamination 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. Controlling the temperature and pressure within the above ranges tends to achieve both good adhesive strength and high total light transmittance.

[0110] [Process (IV)] When the organic phosphorus compound (BO), the polymer (F) and / or other components are used in the above-mentioned production method, 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 the step (I), the layer (Y) obtained in the step (II), or the precursor layer of the layer (Y) after the step (II-1), followed by a drying treatment. When the step (IV) is performed after the step (II-1), it is preferable to perform the step (II-2) after the drying treatment of the 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] The conditions for removing the solvent (drying treatment) after application of the coating liquid (T) in step (IV) can be the same as the conditions for drying treatment after application of the coating liquid (S) in step (I).

[0115] [Electronic Devices] An electronic device using the multilayer structure of the present invention includes 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 solely 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. Furthermore, other stabilizers, light stabilizers, antioxidants, etc. may be used in combination.

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

[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 standpoint of cost.

[0124] The protective sheet for an electronic device of the present invention is preferably directly bonded to an encapsulant from the viewpoints of reducing the thickness and improving the flexibility of the resulting electronic device, and 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 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 in FIG. 1 includes an electronic device body 41, a sealant 42 for sealing the electronic device body 41, and a protective sheet (including a multilayer structure) 43 for protecting the surface of the electronic device body 41. The sealant 42 covers the entire surface of the electronic device body 41. The protective sheet 43 is disposed on one surface of the electronic device 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 so as to protect the surface of the electronic device 41. The protective sheet 43 may be disposed on the electronic device body 41 via another member such as the sealant 42, or may be disposed directly on the surface of the electronic device 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 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 monocrystalline 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. The solar cell may be an integrated solar cell in which multiple 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] Protective sheet 43 includes the multilayer structure of the present invention. Protective sheet 43 may be composed solely of the multilayer structure. Alternatively, 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 restrictions on the thickness or material of 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 aspects may be preferable. (1) Protective sheet / sealant / electronic device body / sealant / protective sheet (2) Protective sheet / adhesive layer / encapsulant / electronic device body / encapsulant / adhesive layer / protective sheet As the sealing material, EVA is preferably used. As the adhesive layer, the same material as the adhesive layer (I) may be used. [Example]

[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 Examples and Comparative Examples> Base material (X) PET12: Biaxially oriented polyethylene terephthalate film; 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; 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. Mixing 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, Mitsui Chemicals Tocello "Solar Ace (trademark)", thickness 200 μm TPO200: Thermal polyolefin, dnpSolar "PV-FS CVF (product name)", thickness 200 μm PVB250: Polyvinyl butyral film, manufactured by Kuraray Co., Ltd., "MOWITAL (trademark) Thin Film 250 (product name)", thickness 250 μm Other layers ETFE25: Ethylene-tetrafluoroethylene copolymer film, thickness 25 μm

[0133] <Evaluation method> (1) Infrared absorption spectrum measurement 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: Equipment: PerkinElmer Spectrum One Measurement mode: Attenuated total reflection Measurement area: 800cm -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-sections of the multilayer structures were observed using a field emission transmission electron microscope, and the thickness of each layer and the thickness of the multilayer structure itself were calculated. The measurement conditions were as follows: Equipment: JEM-2100F manufactured by JEOL Ltd. Accelerating voltage: 200 kV Magnification: 250,000x

[0135] (3) Total light transmittance, 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 used as the measured value. When the multilayer structure had an asymmetric configuration, the multilayer structure was attached so that the layer (Y) was closest 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 properties) The multilayer structures obtained in the examples and comparative examples were attached to a water vapor transmission rate measuring device, and the water vapor permeability (water vapor transmission rate) was measured by a differential pressure method in accordance with ISO15106-5. The measurement conditions were as follows: 2 ·day), it was determined that the moisture permeability was insufficient. If layer (Y) was exposed, the measurement was carried out after laminating PET12 to prevent damage to layer (Y) during installation in the device or decompression, which would prevent accurate measurement of moisture permeability. The lamination method is as follows. <Lamination method> A two-component adhesive ("Takelac" (registered trademark) brand "A-520" manufactured by Mitsui Chemicals, Inc. and "Takenate" (registered trademark) brand "A-50" manufactured by Mitsui Chemicals, Inc.) was applied to PET12 using a bar coater so that the adhesive layer would be 3 μm thick after drying, and then laminated with the exposed layer (Y) of the multilayer structure obtained in the examples and comparative examples, and left to stand at 40°C for 5 days for aging. <Moisture permeability measurement conditions> Equipment: TECHNOLOX DELTAPERM Temperature: 40℃ Humidity on the steam supply side: 90%RH

[0137] (5) Roll formability (flexibility) The multilayer structures obtained in the Examples and Comparative Examples were cut into a length of 29.7 cm (MD direction) and 21 cm (TD direction), and rolled lengthwise into a roll with a diameter of 2 cm. 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 then placed in the center of the roll. The rolling force was then released, and the roll shape was maintained by the rubber band alone. The diameters at both ends were then measured. This measurement was performed five times, and a total of 10 points were averaged. A value of less than 4.2 cm was assigned an A rating, a value that expanded from 4.2 cm to less than 4.5 cm was assigned a B rating, and a value that expanded to 4.5 cm or more was assigned a C rating. A rating of C was given to indicate insufficient flexibility.

[0138] (6) Flexibility The multilayer structures obtained in the examples and comparative examples were cut to 210 mm × 297 mm (A4 size) and subjected to 10 cycles of bending using a Gelbo Flex Tester (manufactured by Rigaku Kogyo Co., Ltd.) in accordance with ASTM F-392. Of the multilayer structures subjected to bending, 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 bending resistance.

[0139] <Example of manufacturing 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 agglomerates of the hydrolysis and condensation product particles. 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 homogeneous, 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, yielding the target coating solution (S-1). The molar ratio of aluminum atoms to phosphorus atoms in coating solution (S-1) was aluminum atoms:phosphorus atoms = 1.15:1.00.

[0140] <Example of manufacturing 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 "Kuraray Poval (registered trademark) 48-80" to obtain an aqueous PVA 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] <Example of aluminum oxide vapor deposition film production> PET12 was used as the substrate (X), and deposition was carried out using an electron beam heating vacuum deposition device and metallic aluminum under the introduction of oxygen gas, to form a 20 nm thick inorganic oxide layer made of aluminum oxide on the substrate (X).

[0142] <Example of silicon oxynitride sputtering film production> PET25 was used as the substrate (X) and set in the chamber of a batch sputtering device. Then, silicon nitride with a sintered density of 60% was set in the chamber as the 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 x 10 ―4 After the pressure was reduced to 100 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 the corona treatment device TEC-4AC manufactured by Kasuga Electric Co., Ltd. was used at 130 W·min / m 2One side of the substrate (X) was subjected to a surface treatment at a strength of 1000 kJ / cm. The coating liquid (R-1) was applied to one side 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 side of the substrate on which the adhesive layer (AC) had been 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. Next, the other side was surface-treated in the same manner, and then an adhesive layer (AC) and a precursor layer of layer (Y) were formed. The film on which the precursor layer of the obtained 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 wavenumber (Imax) in the region was evaluated. The maximum absorption wavenumber (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 a structure of laminate (1) / adhesive layer (I) / laminate (1) = Y / / PET25 / / Y / I / Y / / PET25 / / Y (" / / " in the examples refers to adhesive layer (AC)) 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.

[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) produced 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: Nisshinbo Mechatronics Inc. 1522N Vacuuming time: 8 minutes Temperature: 160℃ Time: 30 minutes Pressure: 30kPa

[0147] 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.

[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 the corona treatment device TEC-4AC manufactured by Kasuga Electric Co., Ltd. was used at 130 W·min / m 2One side of the substrate (X) was subjected to a surface treatment at a strength of 1000 kJ / cm. The coating liquid (R-1) was applied to one side 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 side 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 of 1108 cm was evaluated. -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 would be 3 μm, and the coating was dried at 70°C for 8 minutes to form an adhesive layer (I). A laminate (2) was laminated onto the adhesive layer (I), and the resulting mixture was allowed to stand at 23°C for 10 days and then at 40°C for 4 days for aging, yielding a multilayer structure having a structure of laminate (1) / adhesive layer (I) / laminate (2)=Y / / PET25 / / 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.

[0151] Example 10 Except for not forming the adhesive layer (AC), 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. The results are shown in Table 1.

[0152] <Examples 11 to 13> A laminate and a multilayer structure 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) prepared in Example 9 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 (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 the adhesive layer (I) was formed by drying at 70 ° C. for 8 minutes, and 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 laminate was left standing at 23°C for 10 days and then at 40°C for 4 days for aging. A multilayer structure having the following structure was obtained: 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 prepared 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 prepare 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) prepared in Example 9 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 (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 the same method, 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) using a bar coater so that the thickness after drying was 3 μm, and dried at 70 ° C for 8 minutes to form an adhesive layer (I). This was then laminated with the laminate (2-1), resulting in 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. 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.

[0156] [Table 1]

[0157] Example 11 A solar cell having a configuration of ETFE25 / EVA200 / multilayer structure / EVA200 / CIGS solar cell / EVA200 / multilayer structure was fabricated by vacuum laminating the multilayer structure fabricated in Example 1, EVA200, ETFE25, and a CIGS solar cell under the conditions described in Example 5. The photoelectric conversion efficiency of the resulting 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%.

[0158] Example 12 A solar cell was fabricated in the same manner as in Example 11, except that EVA200 was changed to POE200. 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%.

[0159] Example 13 A solar cell was fabricated in the same manner as in Example 11, except that EVA200 was changed to TPO200. 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%.

[0160] Example 14 A solar cell was fabricated in the same manner as in Example 11, except that EVA200 was changed to PVB250. 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%.

[0161] Example 15 A solar cell having a configuration of ETFE25 / EVA200 / multilayer structure / EVA200 / CIGS solar cell / EVA200 / multilayer structure was fabricated by vacuum laminating the multilayer structure fabricated in Example 1, EVA200, ETFE25, and a perovskite solar cell under the conditions described in Example 5. The photoelectric conversion efficiency of the resulting 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%. [Explanation of symbols]

[0162] 40 Electronic Devices 41 Electronic device body 42 Encapsulating material 43 Protective Sheet

Claims

1. A laminate (α) including a substrate (X) and a layer (Y), and a laminate (β) including a substrate (X) and a layer (Y′), the layer (Y) contains a reaction product (D) of a metal oxide (A) containing aluminum atoms 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 carbonitrides, and the reaction product (D); The laminate (α) and the laminate (β) are laminated via an adhesive layer (I), The total light transmittance measured in accordance with JIS K 7361-1:1997 is 87% or more, and the moisture permeability measured in accordance with ISO 15106-5 is 2.0 × 10 －３ g / m ２ - A multilayer structure having a thickness of 0.1 to 1.5 mm.

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

3. 3. The multilayer structure according to claim 1, 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. 3. The multilayer structure according to claim 1, wherein the thickness of one layer of the substrate (X) is 100 μm or less.

6. 3. The multilayer structure according to claim 1 or 2, wherein the adhesive layer (I) comprises 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. 3. The multilayer structure according to claim 1, wherein the adhesive layer (I) is a layer formed using a two-component adhesive.

9. 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 3. The multilayer structure according to claim 1, wherein the thickness of the multilayer structure is in the range of 100 nm to 150 nm.

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 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 The method includes a step (III) of laminating at least one of the laminates obtained through the step (II) via an adhesive layer (I), In step (III), 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 laminating a laminate via an adhesive layer (I) and then aging the laminate, The drying temperature in step (III-AI) is 45° C. or higher and 150° C. or lower, 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 30 days or shorter, and condition 2, in which aging is performed at a temperature of 35°C or higher but 70°C or lower for 1 day or longer and 30 days or shorter; A method for producing the multilayer structure according to claim 8.

12. A protective sheet for electronic devices, 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 comprising the protective sheet according to claim 12.

Images