JP2012213937A - Moisture-proof laminate sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture-proof laminate sheet having both of excellent interlayer strength and water vapor barrier property.SOLUTION: The moisture-proof laminate sheet has at least five layers consisting of a weather-resistant film layer, an adhesive (I) layer, a water vapor barrier film layer, an adhesive (II) layer and a sealant layer in this order. The water vapor barrier film layer is composed of a water vapor barrier film obtained by laminating an inorganic thin film layer on one surface of a base material, and the inorganic thin film layer-formed side surface is arranged on the side of the weather-resistant film layer. The adhesive (I) composing the adhesive (I) layer has ≤20 MPa storage elastic modulus E1 when measured at 25°C, at 10 Hz frequency and at 0.1% strain. The adhesive (II) composing the adhesive (II) layer has ≥5 MPa storage elastic modulus E2 when measured at 25°C, at 10 Hz frequency and at 0.1% strain. Here, E2>E1 is satisfied.

Description

  The present invention relates to a laminated moisture-proof sheet, and more particularly to a laminated moisture-proof sheet used for electronic devices such as solar cells.

A water vapor barrier film in which an inorganic thin film such as silicon oxide is formed on the surface of a plastic film substrate is laminated with other plastic films and used for various packaging applications. In recent years, liquid crystal display elements, solar cells, electromagnetic wave shields, touch panels, organic electroluminescence (EL) elements, organic TFTs, organic semiconductor sensors, organic light emitting devices and other organic devices, electronic paper, film capacitors, inorganic EL elements, color filters It is also used for new applications such as base film, surface protection material, vacuum heat insulating material, etc.
For example, one aspect of a general laminated structure of a surface protection sheet for solar cells is (outer) weather resistant film layer / adhesive layer / water vapor barrier film layer / adhesive layer / sealant layer (inner side) in this order. Laminated ones are known.

For example, in Patent Document 1, an adhesive layer is provided on a moisture-proof film based on a biaxially stretched polyester film using a polyurethane-based adhesive (main agent Takelac A511 / curing agent Takenate A50 = 10/1 solution). A surface protective material for solar cells is manufactured by laminating films, and the barrier and interlayer strength after an accelerated test for 1000 hours at 85 ° C. and 85% humidity are evaluated, and a proposal for preventing deterioration of both characteristics is made.
Moreover, in patent document 2, after bonding a PVF film to the moisture-proof film which uses a biaxially stretched polyester film as a base material using a two-component curable polyurethane adhesive, a pressure cooker test (PCT) (by high temperature and high pressure) (Severe environmental test, 105 ° C for 92 hours) The moisture-proof performance and interlaminar strength before and after are evaluated, and the proposal of prevention of deterioration of characteristics is made.

JP 2009-188072 A JP 2009-49252 A

  In recent years, with respect to laminated moisture-proof sheets used for electronic devices such as solar cells, higher performance is required with respect to weather resistance, moisture resistance, durability, and the like. However, even if the method described in the above-mentioned patent document is used, it is not sufficient for obtaining a laminated moisture-proof sheet having both excellent interlayer strength and water vapor barrier property.

  Therefore, an object of the present invention is to provide a laminated moisture-proof sheet having both excellent interlayer strength and water vapor barrier properties.

In the laminated moisture-proof sheet laminated in the order of a conventional weather-resistant film layer / adhesive layer / water vapor barrier film layer / adhesive layer / sealant layer, water vapor enters the inside of the sheet from the end face of the sheet. It was found that the water vapor barrier property may be adversely affected. As a result of extensive studies, the use of an adhesive having a high storage elastic modulus as an adhesive for bonding the water vapor barrier film layer and the sealant layer increases the water vapor barrier property of the adhesive layer itself, We found that we can prevent invasion.
On the other hand, as described in the above patent document, the water vapor barrier film layer has an inorganic thin film layer formed on one side of the substrate. When the adhesive having a high storage elastic modulus is used as an adhesive for bonding the surface on the inorganic thin film layer side of the water vapor barrier film layer and the weather resistant film layer, the present inventors are relatively hard and have low flexibility. The inventors have found that the interlayer strength is not sufficient and peeling may occur.
As the adhesive in the two adhesive layers of the laminated moisture-proof sheet having the above five-layer structure, the same adhesive is usually used from the viewpoint of productivity. However, as a result of further earnest studies, the present inventors are excellent on the basis of a novel idea that adhesives having different performances are used in the two adhesive layers of the laminated moisture-proof sheet having the five-layer structure. It was found that the interlayer strength and water vapor barrier properties can be compatible. The present invention has been made based on these findings.

That is, the present invention provides the following laminated moisture-proof sheet.
It has at least five layers of a weather resistant film layer, an adhesive (I) layer, a water vapor barrier film layer, an adhesive (II) layer and a sealant layer in this order, and the water vapor barrier film layer is inorganic on one side of the substrate. An adhesive that comprises a water vapor barrier film formed by laminating thin film layers, and is a laminated moisture-proof sheet in which the surface on the inorganic thin film layer side is disposed on the weather resistant film layer side, and constitutes the adhesive (I) layer The storage elastic modulus E1 of (I) at 25 ° C., 10 Hz, and strain 0.1% is 20 MPa or less, and the adhesive (II) constituting the adhesive (II) layer has a temperature of 25 ° C., 10 Hz, strain 0. A laminated moisture-proof sheet having a storage elastic modulus E2 at 1% of 5 MPa or more and E2> E1.

  The laminated moisture-proof sheet of the present invention has excellent interlayer strength and water vapor barrier properties. By applying the laminated moisture-proof sheet of the present invention as a surface protection member for an electronic device such as a solar battery, it is possible to prevent performance deterioration of the electronic device such as a solar battery and improve the durability of the electronic device.

The laminated moisture-proof sheet of the present invention has at least five layers of a weather resistant film layer, an adhesive (I) layer, a water vapor barrier film layer, an adhesive (II) layer and a sealant layer in this order.
Hereinafter, each layer will be described in detail.

(Weather-resistant film layer)
The film constituting the weather resistant film layer is not particularly limited as long as it has excellent weather resistance, and any film can be used. For example, polytetrafluoroethylene (PTFE), 4-fluoroethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoropropylene copolymer (FEP), 2-ethylene-4- Fluoropolymer films such as fluorinated ethylene copolymer (ETFE), poly-3-fluoroethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF), or acrylic, polycarbonate, polyethylene terephthalate (PET) ), A resin composition obtained by kneading an ultraviolet absorber into a resin such as polyethylene naphthalate (PEN), or the like is preferably used. Although the said resin can also be used by 1 type, it can also be used in combination of 2 or more type.
Among these, from the viewpoint of long-term durability, 2-ethylene-4-fluoroethylene copolymer (ETFE) and 4-fluoroethylene-6-fluoropropylene copolymer (FEP) are more preferably used. . Also, from the viewpoint of long-term weather resistance and film shrinkage, a resin composition obtained by coating and kneading a UV absorber on a resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) is preferably used. It is done. Among these, from the viewpoint of film properties, a biaxially stretched polyethylene naphthalate film, a polyethylene terephthalate and / or a coextruded biaxially stretched film of polyethylene naphthalate and other plastics are preferable.
In consideration of use in solar cell protective materials, the film is preferably a weather-resistant film that is highly flexible and has excellent heat resistance, moisture resistance, and UV durability, such as a fluorine-based film and a hydrolysis-resistant polyester. A film is preferably used.

  The thickness of the weather-resistant film is generally about 20 to 200 μm, preferably 20 to 100 μm, more preferably 20 to 50 μm from the viewpoints of film handling and cost.

(Adhesive (I) layer)
The adhesive (I) layer has a role of bonding the weather resistant film layer and the water vapor barrier film layer together. Since the adhesive (I) layer in the laminated moisture-proof sheet of the present invention is disposed outside the water vapor barrier film layer, the water vapor barrier property is secured by the water vapor barrier film layer. Therefore, the adhesive (I) layer is required to be superior in interlayer strength rather than the water vapor barrier property of the layer itself.
From the viewpoint of interlayer strength, the storage elastic modulus E1 at 25 ° C., 10 Hz, and strain 0.1% of the adhesive (I) constituting the adhesive (I) layer is 20 MPa or less, preferably 18 MPa or less. Preferably it is 10 MPa or less. The lower limit of the storage elastic modulus E1 is not particularly limited, but is preferably 1 MPa or more, more preferably 3 MPa or more, and further preferably 5 MPa or more from the viewpoint of adhesiveness and the like.
In addition, the storage elastic modulus E1 can be measured using a viscoelasticity measuring apparatus (For example, the product made by IT measurement Co., Ltd., brand name: Viscoelastic spectrometer DVA-200).

  The adhesive (I) constituting the adhesive (I) layer is not particularly limited as long as it has a specific storage elastic modulus E1. The type of the adhesive is not particularly limited, and any adhesive such as a polyurethane adhesive, an acrylic resin adhesive, a polyolefin adhesive, and the like can be used. In the present invention, the adhesive (I) has a specific storage elastic modulus, sufficient weather resistance, maintains adhesive strength for long-term outdoor use, and is stable with little structural change after curing. From the viewpoint of being, etc., a polyurethane-based adhesive is preferable.

  The adhesive (I) is preferably a two-component adhesive from the viewpoint of controlling the storage elastic modulus E1 within a specific range. In the case of a two-component adhesive, the adhesive (I) having a specific storage elastic modulus E1 can be prepared by appropriately selecting the type and blending ratio of the main agent and the curing agent.

In order to prepare the adhesive (I) having a specific storage elastic modulus E1, it is preferable that the crosslinking proceeds sufficiently by applying and curing the adhesive, and the remaining uncrosslinked functional groups are small. As a main component of the polyurethane-based adhesive, a polyol having a molecular weight of 400 to 20000 can be preferably used in consideration of a balance between coating film formability and reactivity at the time of curing, and a polyol having a molecular weight of 600 to 10,000 is more preferably used. it can.
In order for the crosslinking reaction to proceed sufficiently when the adhesive is cured, the hydroxyl group of the polyol of the main agent and the isocyanate group of the curing agent must be sufficiently close to each other. That is, the curing agent needs to penetrate between the polymer chains of the main component polyol. For this purpose, the molecular weight of the curing agent is preferably smaller than that of the polyol, and the molecular weight of the diisocyanate or polyisocyanate contained in the curing agent is preferably 300 to 10,000, more preferably 1,000 to 5,000.

In order to obtain a sufficient crosslinking density and to suppress the number of remaining functional groups, based on the idea of using a main agent and a curing agent having different molecular weights, for example, a method using a mixture of polyols having different molecular weights as the main agent is also preferable. Can be used. Conversely, the molecular weight of the main component polyol can be made smaller than the molecular weight of the curing agent polyisocyanate.
The physical properties of the adhesive based on the design as described above are preferably (main agent viscosity / curing agent viscosity) or (curing agent viscosity / main agent viscosity) of 5 or more, more preferably 10 or more. It is. Moreover, 100-1500 mPa * s (25 degreeC) is preferable, and, as for the viscosity of a main ingredient, More preferably, it is 400-1300 mPa * s (25 degreeC). As a viscosity of a hardening | curing agent, 30-3000 mPa * s (25 degreeC) can be used preferably.

Specific examples of the main agent of the adhesive include polycarbonate polyols, polyether polyols, acrylic polyols, polyurethane polyols, and compositions containing polyester polyols. From the viewpoint of thermal stability, humidity stability, etc., polycarbonate polyols, More preferred is one containing at least one selected from the group consisting of polyether polyol, polyurethane polyol and polyester polyol. A polyester polyol having a molecular weight per ester group of 120 or more can also be preferably used.
Among the above compositions, in the present invention, in particular, those containing at least one selected from the group consisting of polycarbonate polyol, polyether polyol and polyurethane polyol are preferably 30% by mass or more, more preferably 30 to 70% by mass. Can be used.
The other component is preferably added in an amount of 0 to 30% by mass. As the other component, an acrylic polymer, an epoxy polymer, a polyolefin or the like for improving adhesion is preferable. Further, styrene-butadiene rubber and the like excellent in high cold resistance and hydrolysis resistance can be preferably used.

  Examples of the composition of the polycarbonate polyol include methylene carbonate, ethylene carbonate, diphenyl carbonate and the like, and those containing diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol (NPG), and cyclohexanediol.

  Examples of the composition of the polyether polyol include alkylene oxides such as ethylene oxide, propylene oxide, and tetrahydrofuran. A polyether polyol can be obtained by performing ring-opening polymerization using an alkali catalyst or an acid catalyst as a catalyst. As the active hydrogen-containing compound serving as a starting material for ring-opening polymerization, polyhydric alcohols such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,6-hexanediol can be used.

  The acrylic polyol composition can be obtained by copolymerizing an acrylic acid derivative monomer alone or with another monomer. Examples of acrylic acid monomers include hydroxyethyl methacrylate, hydroxypropyl methacrylate, and hydroxybutyl methacrylate. Preferable examples include acrylic polyols copolymerized with monomers such as methyl methacrylate, butyl methacrylate, and cyclohexyl methacrylate having an alicyclic structure. Furthermore, as a monomer to be copolymerized, a functional monomer such as 4-hydroxybutyl acrylate glycidyl ether having an epoxy group that crosslinks by reacting with isocyanate, carboxylic anhydride or the like is arbitrarily selected and designed. Can do.

The composition of polyurethane polyol can be obtained by urethanization of diol and diisocyanate at a ratio of hydroxyl group to isocyanate group of 1 or more. As the polyurethane polyol composition, a diol component and a diisocyanate component can be arbitrarily selected.
The diol component and diisocyanate component can be selected in consideration of the fluidity of the polyurethane polyol and the solubility in a solvent. The diol component is preferably a diol having a primary hydroxyl group such as propylene glycol, tetramethylene glycol, or neopentyl glycol. Examples of the isocyanate component include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic isocyanates.

  Polyester polyol compositions include, for example, dicarboxylic acid compounds such as succinic acid, glutaric acid, adipic acid, isophthalic acid (IPA), terephthalic acid (TPA), and ethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexanediol. And those containing a polyether polyol such as polytetramethylene glycol.

An adhesive using polyester polyol as a raw material is preferable in terms of high adhesion to a base material, but from the viewpoint of suppressing thermal deterioration due to hydrolysis of ester bonds, a polyester polyol having a small number of ester bond groups that can serve as hydrolysis points. Is preferably selected. For example, a glycol having a long alkyl chain such as neopentyl glycol (NPG), for example, a glycol having an alicyclic structure such as 1,4-cyclohexanedimethanol is preferable.
Furthermore, it is preferable to select a hydrolyzed polyester polyol having a polyether structure in the main chain structure, such as polytetramethylene glycol (PTMG). As such a polyester polyol, the molecular weight per ester group is preferably 50 to 8000, more preferably 100 to 5000, and still more preferably 120 to 3000.

As the curing agent, diisocyanate is preferable. For example, aliphatic type such as hexamethylene diisocyanate (HDI), aromatic type such as xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), dicyclohexylmethane diisocyanate (H12MDI). ) And the like.
As a curing agent having high heat resistance after curing, for example, XDI which is an aromatic diisocyanate, or IPDI which is an alicyclic diisocyanate is preferable. Furthermore, in order to prevent yellowing of the adhesive, IPDI which is an alicyclic diisocyanate is more preferable.

When the main component contains polycarbonate polyol, it is excellent in terms of high heat resistance and high moisture resistance, but from the viewpoint of obtaining a sufficient crosslinking density even during curing, HDI having a flexible methylene chain is combined as a curing agent. It is preferable.
Moreover, in order to obtain a more thermally stable adhesive layer, it is preferable to use a material containing an epoxy compound as a main component.
A preferable blending ratio (mass ratio) of the main agent and the curing agent of the adhesive (I) is main agent / curing agent = 5 to 25, more preferably 15 to 20, and (—OH group / —NCO group) = 0. 0.05 to 1.2, more preferably 0.1 to 1.

  It is preferable to add an ultraviolet absorber to the adhesive in the present invention. The addition amount of the ultraviolet absorber is usually about 0.01 to 2.0% by mass in the adhesive, and preferably 0.05 to 0.5% by mass.

  In addition to the above ultraviolet absorbers, hindered amine light stabilizers are suitably used as weather stabilizers that impart weather resistance. A hindered amine light stabilizer does not absorb ultraviolet rays like an ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with an ultraviolet absorber. The amount of the hindered amine light stabilizer added is usually about 0.01 to 0.5% by mass in the adhesive, and preferably 0.05 to 0.3% by mass.

The adhesive layer (I) can be provided by, for example, a roll coating method, a gravure roll coating method, a kiss coating method, other coating methods, a printing method, or the like. The application amount of the adhesive (I) is preferably about 0.1 to 10 g / m ² (dry state).

(Water vapor barrier film layer)
The water vapor barrier film layer in the laminated moisture-proof sheet of the present invention is a water vapor barrier film in which an inorganic thin film layer is laminated on one side of a substrate.

<Base material>
The substrate is preferably a transparent substrate film, specifically, a thermoplastic polymer film is preferable, and the material is not particularly limited as long as it is a resin that can be used for ordinary packaging materials. be able to.
Specifically, polyolefins such as homopolymers or copolymers such as ethylene, propylene and butene, amorphous polyolefins such as cyclic polyolefins, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), nylon 6 , Nylon 66, nylon 12, polyamide such as copolymer nylon, ethylene-vinyl acetate copolymer partial hydrolyzate (EVOH), polyimide, polyetherimide, polysulfone, polyethersulfone, polyetheretherketone, polycarbonate, polyvinyl Examples include butyral, polyarylate, fluororesin, acrylate resin, and biodegradable resin. Among these, polyesters, polyamides, and polyolefins are preferable from the viewpoints of film properties and cost. Among these, polyesters are more preferable in terms of surface smoothness, film strength, heat resistance, and the like, and polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are particularly preferable.

  The base film is a known additive such as an antistatic agent, a light blocking agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained.

The thermoplastic polymer film as the substrate is formed by using the above raw materials, but when used as a substrate, it may be unstretched or stretched. . Moreover, you may laminate | stack with the other plastic base material.
Such a base film can be produced by a conventionally known method. For example, a raw material resin is melted by an extruder, extruded by an annular die or a T die, and rapidly cooled to be oriented substantially amorphously. No unstretched film can be produced. Further, by using a multilayer die, it is possible to produce a single layer film made of one kind of resin, a multilayer film made of one kind of resin, a multilayer film made of various kinds of resins, and the like.

  The unstretched film is subjected to a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like. A film stretched in at least a uniaxial direction can be produced by stretching in a direction (horizontal axis) perpendicular thereto. Although a draw ratio can be set arbitrarily, it is preferable that 150 degreeC heat shrink rate is 0.01 to 5%, Furthermore, it is preferable that it is 0.01 to 2%. Among these, from the viewpoint of film properties, a biaxially stretched polyethylene naphthalate film, a polyethylene terephthalate and / or a coextruded biaxially stretched film of polyethylene naphthalate and other plastics are preferable.

  In addition, it is preferable to apply | coat an anchor coating agent to the said base film for the adhesive improvement with an inorganic thin film. As anchor coating agents, solvent-based or water-soluble polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl-modified resins, vinyl alcohol resins, vinyl butyral resins, ethylene vinyl alcohol resins, nitrocellulose resins, oxazoline group-containing resins, carbodiimides A group-containing resin, a methylene group-containing resin, an epoxy group-containing resin, a modified styrene resin, a modified silicone resin, an alkyl titanate, or the like can be used alone or in combination of two or more. In addition, additives such as silane coupling agents, titanium coupling agents, light blocking agents, ultraviolet absorbers, stabilizers, lubricants, antiblocking agents, antioxidants, etc. may be included, and those Additives may be copolymerized with the resin.

  The thickness of the anchor coat layer is preferably 10 to 200 nm, and more preferably 10 to 100 nm, from the viewpoint of improving the adhesion with the inorganic thin film. A known coating method is appropriately adopted as the formation method. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, a spray or a coating method using a brush can be used. Alternatively, the vapor deposition film may be immersed in a resin solution. After coating, the solvent can be evaporated using a known drying method such as hot drying such as hot air drying or hot roll drying at a temperature of about 80 to 200 ° C. or infrared drying. Moreover, in order to improve water resistance and durability, the crosslinking process by electron beam irradiation can also be performed. Further, the formation of the anchor coat layer may be a method performed in the middle of the substrate film production line (inline) or a method performed after the substrate film is manufactured (offline).

<Inorganic thin film layer>
As an inorganic thin film layer constituting a laminated moisture-proof film, a metal coating film such as aluminum is known, but when applied to an electronic device such as a solar cell, it has excellent transparency without fear of leakage of current. Therefore, a coating film of inorganic oxide such as silica and alumina is preferably used.

  As a method for forming the inorganic oxide coating layer, any of a vapor deposition method and a coating method can be used, but a vapor deposition method is preferable in that a uniform thin film having a high gas barrier property can be obtained. This vapor deposition method includes any method such as physical vapor deposition (PVD) or chemical vapor deposition (CVD). Examples of physical vapor deposition include vacuum vapor deposition, ion plating, and sputtering, and chemical vapor deposition includes plasma CVD using plasma and a catalyst that thermally decomposes a material gas using a heated catalyst body. Examples include chemical vapor deposition (Cat-CVD).

  Examples of the inorganic substance constituting the inorganic oxide coating layer include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrogenated carbon, and the like, or oxides, carbides, nitrides, or mixtures thereof. Since it is transparent, diamond like carbon mainly composed of silicon oxide, aluminum oxide, and hydrogenated carbon is preferable. In particular, silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxide are preferable in that high gas barrier properties can be stably maintained.

  The thickness of the coating film is preferably 40 to 1000 nm, more preferably 50 to 800 nm, and still more preferably 50 to 600 nm from the viewpoint of stable moistureproof performance. Moreover, generally the thickness of the said base film is about 5-100 micrometers, 8-50 micrometers is preferable from the point of productivity or ease of handling, and 10-25 micrometers is still more preferable.

(Adhesive (II) layer)
The adhesive (II) layer in the laminated moisture-proof sheet of the present invention has a role of bonding the water vapor barrier film layer and the sealant layer, and also has a role of preventing water vapor from entering from the sheet end face.
Since the adhesive (II) layer is disposed inside the water vapor barrier film layer, if the water vapor barrier property of the adhesive layer itself is low, water vapor may enter from the sheet end face. Therefore, the water vapor barrier property of the layer itself is required for the adhesive (II) layer in the laminated moisture-proof sheet of the present invention.

From the viewpoint of water vapor barrier properties, the storage elastic modulus E2 at 25 ° C., 10 Hz, and strain 0.1% of the adhesive (II) constituting the adhesive (II) layer is 5 MPa or more, preferably 10 MPa or more. More preferably, it is 20 MPa or more. The upper limit of the storage elastic modulus E2 is not particularly limited, but is preferably 50 MPa or less, more preferably 30 MPa or less from the viewpoint of interlayer strength and the like.
The storage elastic modulus E2 can also be measured using a viscoelasticity measuring device (for example, product name: Viscoelastic Spectrometer DVA-200, manufactured by IT Measurement Co., Ltd.) and the like, similar to the storage elastic modulus E1. it can.

  The adhesive (II) constituting the adhesive (II) layer is not particularly limited as long as it has a specific storage elastic modulus E2. The type of the adhesive is not particularly limited, and can be appropriately selected from those described in the adhesive (I). Specifically, as the adhesive (II), any adhesive such as a polyurethane-based adhesive, an acrylic resin-based adhesive, and a polyolefin-based adhesive can be used, and among them, a polyurethane-based adhesive is preferable.

  The adhesive (II) is preferably a two-component adhesive from the viewpoint of controlling the storage elastic modulus E2 within a specific range. In the case of a two-component adhesive, the adhesive (II) having a specific storage modulus E2 can be prepared by appropriately selecting the type and blending ratio of the main agent and the curing agent. It can select suitably from what was demonstrated by the said adhesive agent (I). For example, specific examples of the main agent of the adhesive include a composition containing polycarbonate polyol, polyether polyol, acrylic polyol, polyurethane polyol or polyester polyol. From the viewpoint of thermal stability, humidity stability, etc., polycarbonate More preferred is one containing at least one selected from the group consisting of polyol, polyether polyol, polyurethane polyol and polyester polyol.

  A preferable blending ratio (mass ratio) of the main agent and the curing agent of the adhesive (II) is main agent / curing agent = 5 to 25, more preferably 6 to 12, and (—OH group / —NCO group) = 0. 0.05 to 1.2, more preferably 0.1 to 1.

The adhesive layer (II) can be provided by, for example, a roll coating method, a gravure roll coating method, a kiss coating method, other coating methods, a printing method, or the like. The application amount of the adhesive (II) is preferably about 0.1 to 10 g / m ² (dry state).

In the laminated moisture-proof sheet of the present invention, in order to achieve both excellent interlayer strength and water vapor barrier properties, it is necessary to consider that the performance required for the adhesive used on the outside and inside of the water vapor barrier film layer is different. I must. From such a viewpoint, it is required to satisfy the relationship of storage elastic modulus E2> storage elastic modulus E1.
From the above viewpoint, it is preferable that the relationship between the storage elastic moduli E1 and E2 satisfies the following condition (1).
(E2-E1) /E2≧0.3 (1)
In order to satisfy the above conditions, the adhesive (I) constituting the adhesive (I) layer is required to be relatively soft, and the adhesive (II) constituting the adhesive (II) layer is relatively It is required to be hard. That is, since the adhesive (I) is relatively soft, it is possible to relieve stress applied at the time of peeling between the weather resistant film layer and the water vapor barrier film layer, and to improve the interlayer strength. On the other hand, the adhesive (II) is required to be relatively hard. This means that the cross-linking of the two-part adhesive is denser or the cohesive strength of the polymer chains in the adhesive is large, and such an adhesive (II) is transmitted through the adhesive. The water vapor | steam to perform can be suppressed and water vapor | steam barrier property can be improved. From such a viewpoint, it is more preferable that the relationship between the storage elastic moduli E1 and E2 satisfies the following condition (2).
(E2-E1) /E2≧0.5 (2)

(Sealant layer)
As the sealant layer, any resin having heat sealing properties such as polyethylene, polypropylene, ethylene copolymer, and saturated polyester can be used according to the purpose. The sealant layer may be provided by laminating a filmed material via an adhesive (II) layer, or by laminating a molten resin by extrusion coating via an adhesive (II) layer. Good.
Generally the thickness of a sealant layer is about 20-200 micrometers, and 30-150 micrometers is preferable from a viewpoint of sealing performance and cost, and 50-100 micrometers is more preferable.

  Each layer of the laminated moisture-proof sheet of the present invention is intended to further improve various physical properties (flexibility, heat resistance, transparency, adhesiveness, etc.), molding processability, economic efficiency, etc. without departing from the gist of the present invention. For example, polyolefin resins and various elastomers (olefins, styrenes, etc.), resins modified with polar groups such as carboxyl groups, amino groups, imide groups, hydroxyl groups, epoxy groups, oxazoline groups, thiol groups, silanol groups And tackifying resins and the like.

Examples of the tackifying resin include petroleum resins, terpene resins, coumarone-indene resins, rosin resins, and hydrogenated derivatives thereof. Specifically, as the petroleum resin, there are an aromatic petroleum resin from alicyclic petroleum resins and C ₉ components from cyclopentadiene or dimer thereof, terpene resins and terpene from The terpene resin β- pinene -As the rosin resin, phenolic resins include rosin resins such as gum rosin and wood rosin, esterified rosin resins modified with glycerin, pentaerythritol, and the like. Further, the tackifying resin can be obtained mainly having various softening temperatures depending on the molecular weight, but hydrogenated derivatives of alicyclic petroleum resins having a softening temperature of 100 to 150 ° C, preferably 120 to 140 ° C are particularly preferable. . The amount of the tackifying resin is usually preferably 20% by mass or less, more preferably 10% by mass or less when the resin composition is 100% by mass.

  Moreover, various additives can be added to the laminated moisture-proof sheet as required. Examples of the additive include a silane coupling agent, an antioxidant, an ultraviolet absorber, a light stabilizer (weather resistance stabilizer), a light diffusing agent, a nucleating agent, a pigment (for example, a white pigment), a flame retardant, and a color change prevention. Agents and the like. In the present invention, it is preferable that at least one additive selected from a silane coupling agent, an antioxidant, an ultraviolet absorber, and a light stabilizer is added. In the present invention, for example, when high heat resistance is required, a crosslinking agent and / or a crosslinking aid may be blended.

  Examples of the silane coupling agent include compounds having a hydrolyzable group such as an alkoxy group together with an unsaturated group such as a vinyl group, an acryloxy group, and a methacryloxy group, an amino group, an epoxy group, and the like. . Specific examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxy. Examples include silane, γ-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane, and the like. In the present invention, γ-glycidoxypropyltrimethoxysilane and γ-methacryloxypropyltrimethoxysilane are preferably used because of good adhesiveness and little discoloration such as yellowing. The addition amount of the silane coupling agent is usually about 0.1 to 5% by mass and preferably 0.2 to 3% by mass in each film constituting the laminated moisture-proof sheet. In addition, similar to the silane coupling agent, a coupling agent such as an organic titanate compound can also be used effectively.

  As the antioxidant, various commercially available products can be applied, and various antioxidants such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be mentioned. Examples of monophenol antioxidants include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and the like. it can. Examples of the bisphenol antioxidant include 2,2′-methylene-bis- (4-methyl-6-tert-butylphenol), 2,2′-methylene-bis- (4-ethyl-6-tert-butylphenol), 4,4′-thiobis- (3-methyl-6-tert-butylphenol), 4,4′-butylidene-bis- (3-methyl-6-tert-butylphenol), 3,9-bis [{1,1 -Dimethyl-2- {β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy} ethyl} 2,4,9,10-tetraoxaspiro] 5,5-undecane, etc. Can do.

Examples of the polymer phenolic antioxidant include 1,1,3-tris- (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6- Tris (3,5-di-tert-butyl-4-bidoxybenzyl) benzene, tetrakis- {methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenyl) propionate} methane Bis {(3,3′-bis-4′-hydroxy-3′-tert-butylphenyl) butyric acid} glycol ester, 1,3,5-tris (3 ′, 5′-di-tert- Butyl-4'-hydroxybenzyl) -s-triazine-2,4,6- (1H, 3H, 5H) trione, triphenol (vitamin E) and the like.
Examples of sulfur-based antioxidants include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

  Phosphite antioxidants include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phos Phyto, cyclic neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenathrene -10-oxide, 10- (3,5-di-tert-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-decyloxy- 9,10-dihydro-9-oxa-1 -Phosphophenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite 2,2-methylenebis (4,6-tert-butylphenyl) octyl phosphite and the like.

  In the present invention, phenol-based and phosphite-based antioxidants are preferably used in view of the effect of the antioxidant, thermal stability, economy and the like, and it is more preferable to use a combination of both. The addition amount of the antioxidant is usually about 0.1 to 1% by mass and preferably 0.2 to 0.5% by mass in each layer constituting the laminated moisture-proof sheet.

Examples of the UV absorber include various UV absorbers such as benzophenone, benzotriazole, triazine, and salicylic acid ester, and various commercially available products can be applied.
Examples of the benzophenone-based UV absorber include 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-2′-carboxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-n. -Dodecyloxybenzophenone, 2-hydroxy-4-n-octadecyloxybenzophenone, 2-hydroxy-4-benzyloxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-5-chlorobenzophenone, 2 , 4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, etc. In That.

The benzotriazole ultraviolet absorber is a hydroxyphenyl-substituted benzotriazole compound, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) Benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole and the like. be able to.
Examples of triazine ultraviolet absorbers include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- ( Examples include 4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol.
Examples of salicylic acid ester ultraviolet absorbers include phenyl salicylate and p-octylphenyl salicylate.

  Examples of the light stabilizer include hindered amine light stabilizers. Examples of hindered amine light stabilizers include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1 , 3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {{2, 2,6,6-tetramethyl-4-piperidyl} imino}], N, N′-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (1,2,2, 6,6-pentamethyl-4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate, bis (2,2,6,6-tetramethyl-4-piperidyl) separate, 2- (3 , 5-Di-tert-4- Mud alkoxybenzylacetic) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like.

  As a method for forming a weatherproof film, a water vapor barrier film and a sealant film constituting the laminated moisture-proof sheet used in the present invention, a known method such as a single screw extruder, a multi-screw extruder, a Banbury mixer, a kneader or the like is melted. Although it has a mixing facility and can adopt an extrusion cast method or a calendar method using a T die, it is not particularly limited, but in the present invention, the T die is used from the aspects of handling property and productivity. The extrusion cast method used is preferably used. The molding temperature in the extrusion casting method using a T-die is appropriately adjusted depending on the flow characteristics and film forming properties of the resin composition to be used, but is generally 130 to 300 ° C, preferably 150 to 250 ° C. Various additives such as silane coupling agents, antioxidants, UV absorbers, and light stabilizers may be dry-blended with the resin in advance and then supplied to the hopper. It may be supplied after producing or a master batch in which only the additive is previously concentrated in the resin may be produced and supplied.

  The laminated moisture-proof sheet of the present invention is obtained by drying the adhesive film at a temperature of 100 to 140 ° C., for example, using the adhesives (I) and (II). It can be manufactured by pasting together by dry lamination at a temperature of. Moreover, it is preferable to cure the obtained laminated body at the temperature of 30-80 degreeC for 1 to 7 days from a viewpoint of making an adhesive agent fully reach | attain saturation bridge | crosslinking degree.

  The thickness of the laminated moisture-proof sheet of the present invention is not particularly limited, but is preferably about 30 to 500 μm, more preferably about 50 to 300 μm, and still more preferably about 80 to 150 μm.

The laminated moisture-proof sheet of the present invention thus obtained includes a weather resistant film layer and a water vapor barrier film layer after a pressure cooker test (conditions: 120 ° C., 32 hours) according to JIS C60068-2-66, which is an accelerated test. The interlayer strength is preferably 4 N / 15 mm or more, more preferably 6 N / 15 mm or more, and still more preferably 8 N / 15 mm or more. Interlayer strength satisfying the above specific value means that the laminated moisture-proof sheet is less likely to cause delamination when applied to a solar cell module or the like, and the laminated moisture-proof sheet of the present invention is excellent in durability.
The interlayer strength can be measured by the method described in the examples.

The laminated moisture-proof sheet of the present invention is preferably 0.20 [g / m as a water vapor transmission rate after a pressure cooker test (conditions: 120 ° C., 32 hours) according to JIS C60068-2-66, which is an acceleration test. ² · day] or less, more preferably 0.15 [g / m ² · day] or less, and still more preferably 0.10 [g / m ² · day] or less. That the water vapor transmission rate satisfies the above specific value can sufficiently prevent water vapor from entering when applied to a solar cell module or the like, and the laminated moisture-proof sheet of the present invention has excellent water vapor barrier properties. .
The moisture-proof performance can be evaluated according to various conditions of JIS Z0222 “Method of testing moisture permeability of moisture-proof packaging container” and JIS Z0208 “Method of testing moisture permeability of moisture-proof packaging material (cup method)”.

  The laminated moisture-proof sheet of the present invention can be used for solar cell applications that require long-term durability, particularly for surface protection members for solar cells. It is preferable because rusting can be prevented, and retention of electromotive force over a long period can be achieved.

  The laminated moisture-proof sheet for solar cells has a moisture-proof property even under high temperature conditions by laminating the specific plastic film to the inorganic thin film layer via the specific polyurethane-based adhesive. Achieves a laminated moisture-proof sheet with excellent flexibility and moisture-proofness that does not degrade the interlayer strength, and at the same time prevents the performance of the solar cell from decreasing, making it possible to reduce the weight, durability, and design of the solar cell, An effective laminated moisture-proof sheet for solar cells can be provided.

<Solar cell module, solar cell manufacturing method>
The laminated moisture-proof sheet can be used as a surface protection member for solar cells as it is or after being laminated with a glass plate or the like. What is necessary is just to produce by the well-known method, in order to manufacture the solar cell module and / or solar cell of this invention using the lamination | stacking moisture-proof sheet | seat of this invention.

  A solar cell module can be produced by using the laminated moisture-proof sheet of the present invention in a layer structure of a surface protection member such as a solar cell front sheet or back sheet, and fixing the solar cell element together with a sealing material. As such a solar cell module, various types can be exemplified, and preferably, when the laminated moisture-proof sheet of the present invention is used as a front surface protective material, a sealing material, a solar cell element, and a lower part And a solar cell module manufactured using a protective material, specifically, an upper protective material (laminated moisture-proof sheet of the present invention) / sealing material (sealing resin layer) / solar cell element / sealing material. (Sealing resin layer) / lower protective material structure, sealing material and upper protective material (laminated moisture-proof sheet of the present invention) are formed on the solar cell element formed on the inner peripheral surface of the lower protective material. A solar cell element formed on the inner peripheral surface of the upper protective material (laminated moisture-proof sheet of the present invention), for example, an amorphous solar cell element produced by sputtering or the like on a fluororesin-based transparent protective material Sealing and bottom protection on top It can be exemplified such as those constituted as to form. It is optional to bond a glass plate to the outside of the laminated moisture-proof sheet of the present invention as the upper protective material.

Examples of solar cell elements include single crystal silicon type, polycrystalline silicon type, amorphous silicon type, III-V group and II-VI group compound semiconductor types such as gallium-arsenic, copper-indium-selenium, cadmium-tellurium, Examples include a dye sensitizing type and an organic thin film type.
In the case of forming a solar cell module using the surface protective material in the present invention, the moisture proof property is less than 1.0 [g / (m ² · day)] depending on the type of the solar cell power generation element. A high moisture-proof film of less than about 0.01 [g / (m ² · day)] is appropriately selected according to the type of the element, and is formed by laminating using a weather-resistant film or the like and an adhesive.

  Although it does not specifically limit about each member which comprises the solar cell module produced using the lamination | stacking moisture-proof sheet | seat of this invention, As a sealing material, an ethylene-vinyl acetate copolymer is mentioned, for example. Can do. The lower protective material is a single layer or multilayer sheet such as metal or various thermoplastic resin films, for example, metals such as tin, aluminum, stainless steel, inorganic materials such as glass, polyester, inorganic vapor deposition polyester, fluorine-containing resin And a single-layer or multilayer protective material such as polyolefin. The surface of the upper and / or lower protective material can be subjected to a known surface treatment such as a primer treatment or a corona treatment in order to improve the adhesion to the sealing material or other members.

  Configuration of an upper protective material (laminated moisture-proof sheet of the present invention) / encapsulant / solar cell element / encapsulant / lower protective material described above for a solar cell module produced using the laminated moisture-proof sheet of the present invention Will be described as an example. In order from the sunlight receiving side, the laminated moisture-proof sheet, sealing resin layer, solar cell element, sealing resin layer, and back sheet of the present invention are laminated, and further, a junction box (from the solar cell element) on the lower surface of the back sheet. A terminal box for connecting wiring for taking out the generated electricity to the outside is bonded. The solar cell elements are connected by wiring in order to conduct the generated current to the outside. The wiring is taken out through a through hole provided in the backsheet and connected to the junction box.

  As a manufacturing method of the solar cell module, a known manufacturing method can be applied and is not particularly limited, but in general, the laminated moisture-proof sheet, the sealing resin layer, the solar cell element, and the sealing resin of the present invention. A step of laminating the layers and the lower protective material in this order, and a step of vacuum-sucking them and thermocompression bonding them. Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.

  The solar cell module produced using the laminated moisture-proof sheet of the present invention is a small solar cell represented by a mobile device, a large solar cell installed on a roof or a roof, etc., depending on the type and module shape of the applied solar cell. It can be applied to various uses, both indoors and outdoors.

  In the solar cell module and / or solar cell of the present invention, this solar cell protective sheet, encapsulant, power generation element, encapsulant, and back surface protective sheet are vacuum laminator according to a conventional method, and the temperature is preferably 130 to 180 ° C., more preferably 130 to 150 ° C., degassing time 2 to 15 minutes, press pressure 0.5 to 1 atm, press time is preferably 8 to 45 minutes, more preferably 10 to 40 minutes. Can be easily manufactured.

  EXAMPLES The present invention will be described more specifically with reference to examples. However, the present invention is not limited by these examples and comparative examples. In addition, measurement and evaluation of various physical properties of the sheets displayed in this specification were performed as follows. In this example, the heat laminating condition was 150 ° C. for 30 minutes.

<Measurement of physical properties>
(1) Storage elastic modulus E1 and E2 of the adhesive layer
Each of the prepared adhesive coating solutions was applied to a silicone release PET film so as to have a solid content coating amount of 20 g / m ^2, and cured at 40 ° C. for 4 days to form an adhesive layer. Thereafter, only the adhesive layer is taken out and stacked with a predetermined thickness, and using a viscoelasticity measuring device (product name: viscoelastic spectrometer DVA-200, manufactured by IT Measurement Co., Ltd.), a sample (4 mm long, 60 mm wide, Measured from -100 ° C to 180 ° C in the transverse direction at a vibration frequency of 10 Hz, vibration frequency of 10 Hz, strain of 0.1%, temperature increase rate of 3 ° C / min, and 25 mm between chucks. The elastic modulus [MPa] was determined. The storage elastic modulus was set to 0 when measurement at 150 ° C. was difficult due to sample shape change at the time of temperature rise.

(2) Interlaminar strength between the weather resistant film layer and the water vapor barrier film layer The laminated moisture-proof sheet is cut into a strip shape having a measurement width of 15 mm, and the cut is deep enough to cut only the weather-resistant film from the weather-resistant film side of the laminated sheet. Put between the weather resistant film layer and the water vapor barrier film layer by removing only the weather resistant film at 300 mm / min using a tensile testing machine (trade name: STA-1150, manufactured by Orientec Co., Ltd.) The strength (N / 15 mm) was measured.

(3) Moisture-proof performance The moisture-proof performance of each laminated moisture-proof sheet (1-5) after curing is determined according to JIS Z0222 “Moisture permeability test method for moisture-proof packaging containers”, JIS Z0208 “Moisture permeability test method for moisture-proof packaging materials (cup method)” According to the conditions of "", it evaluated by the following method.
Using two samples each having a moisture permeable area of 10.0 cm × 10.0 cm square, a bag having about 20 g of anhydrous calcium chloride as a hygroscopic agent and sealed on all sides was produced. The bag was kept at a constant temperature of 40 ° C. and a relative humidity of 90%. It put into the humidity control apparatus, mass measurement was carried out to about the 200th day at intervals of 72 hours or more, and the water vapor transmission rate was calculated from the slope of the regression line between the elapsed time after the fourth day and the bag mass. The lower the water vapor transmission rate, the better the water vapor barrier property.

<Structure film>
[Weather-resistant film]
A 25 μm-thick biaxially stretched polyethylene naphthalate film (manufactured by Teijin DuPont Films, trade name: Teonex Q51C) was used.
[Sealant film]
An unstretched polypropylene film having a thickness of 60 μm (trade name: P1146, manufactured by Toyobo Co., Ltd.) was used.

[Water vapor barrier film]
As a base film, a 12 μm-thick biaxially stretched polyethylene naphthalate film (manufactured by Teijin DuPont Films, trade name: Teonex Q51C12) was used. A coat layer having a thickness of 0.1 μm was formed.
Next, SiO was heated and evaporated under a vacuum of 1.33 × 10 ⁻³ Pa (1 × 10 ⁻⁵ Torr) using a vacuum vapor deposition apparatus, and SiO _x (x = 1. 5) A water vapor barrier film (inorganic thin film film) having a thin film was obtained. The moisture barrier performance of the produced water vapor barrier film was 0.01 [g / m ² · day].

(Coating solution)
20 g of polyvinyl alcohol resin (manufactured by Nippon Gosei Co., Ltd., trade name: Gohsenol, degree of saponification: 97.0 to 98.8 mol%, degree of polymerization: 2400) in 2810 g of ion-exchanged water and dissolved by heating to 20 g While stirring at 0 ° C., 645 g of 35% hydrochloric acid was added. Subsequently, 3.6 g of butyraldehyde was added with stirring at 10 ° C., and after 5 minutes, 143 g of acetaldehyde was added dropwise with stirring to precipitate resin fine particles. Subsequently, after hold | maintaining at 60 degreeC for 2 hours, the liquid was cooled, neutralized with sodium hydrogencarbonate, washed with water, and dried, and the polyvinyl acetoacetal resin powder (acetalization degree 75 mol%) was obtained.
Further, an isocyanate resin (manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name: Sumidur N-3200) was used as a crosslinking agent, and the mixture was mixed so that the equivalent ratio of isocyanate groups to hydroxyl groups was 1: 2.

[Adhesive coating solution]
(Adhesive coating liquid (a))
IS801 (trade name, manufactured by Toyo Ink Mfg. Co., Ltd., molecular weight per ester group: 105, viscosity: 1700 [mPa · sec]) is used as the main component containing the polyester polyol component, and aliphatic hexamethylene diisocyanate. CR001 (trade name, manufactured by Toyo Ink Manufacturing Co., Ltd.) was used as a curing agent containing a component and an alicyclic isophorone diisocyanate.
The above-mentioned main agent IS801 and curing agent CR001 were mixed at a mass ratio of 10: 1, and diluted with ethyl acetate so that the solid content concentration was 30% by mass to prepare an adhesive coating solution (a). .

(Adhesive coating liquid (b))
The above-mentioned main agent IS801 and curing agent CR001 are mixed at a mass ratio of 10: 0.5, diluted with ethyl acetate so that the solid content concentration is 30% by mass, and the adhesive coating liquid (b) is prepared. Prepared.

(Adhesive coating liquid (c))
A1102 (trade name, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is used as a main component containing a polycarbonate polyol component, and A3070 (trade name, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is used as a curing agent containing an aliphatic hexamethylene diisocyanate component. ) Was used.
The above-mentioned main agent A1102 and curing agent A3070 were mixed at a mass ratio of 16: 1, and diluted with ethyl acetate so that the solid content concentration was 30% by mass to prepare an adhesive coating solution (c). .

(Adhesive coating liquid (d))
HD1013 (trade name, manufactured by Rock Paint Co., Ltd.) is used as the main agent containing the polyurethane polyol component, and H62 (trade name, manufactured by Rock Paint Co., Ltd.) is used as the curing agent containing the aliphatic hexamethylene diisocyanate component. used.
The above main agent HD1013 and curing agent H62 are mixed so that the mass ratio is 10: 1.5, diluted with ethyl acetate so that the solid content concentration becomes 30% by mass, and the adhesive coating liquid (d) is obtained. Prepared.

(Adhesive coating solution (e))
The above main agent HD1013 and curing agent H62 are mixed so as to have a mass ratio of 10: 0.5, diluted with ethyl acetate so that the solid content concentration becomes 30% by mass, and the adhesive coating liquid (d) is obtained. Prepared.

(Adhesive coating liquid (f))
A1143 (trade name, manufactured by Mitsui Chemicals Polyurethanes Co., Ltd.) is used as a main agent containing a polyester polyol component, and Takenate A-50 as a curing agent containing an alicyclic isophorone diisocyanate and an aromatic xylylene diisocyanate. (Trade name, manufactured by Mitsui Chemicals, Inc.) was used.
The above main agent A1143 and curing agent Takenate A-50 are mixed so that the mass ratio is 9: 1, and diluted with ethyl acetate so that the solid content concentration becomes 30% by mass, and then the adhesive coating liquid (f) Was prepared.

Example 1
The adhesive coating liquid (b) as the adhesive (I) is applied to the weather resistant film and dried so as to have a solid content of 5 g / m ^2, and is laminated to the inorganic thin film layer side of the water vapor barrier film with a dry laminate. A-1 was obtained. Next, the adhesive coating liquid (a) as an adhesive (II) is applied and dried on the water vapor barrier film of the laminate A-1 so as to have a solid content of 5 g / m ^2, and the sealant film is bonded by dry lamination, The laminate was cured at 60 ° C. for 5 days to prepare a laminated moisture-proof sheet (1).
The laminated moisture-proof sheet (1) was subjected to a pressure cooker test (conditions: 120 ° C., 32 hours), and then measured for water vapor permeability and interlayer strength between the weather resistant film layer and the water vapor barrier film layer. It was.

Example 2
Laminated moisture-proof sheet (2) in the same manner as in Example 1 except that the adhesive coating liquid (e) was used as the adhesive (I) and the adhesive coating liquid (d) was used as the adhesive (II). Was prepared, and the interlayer strength between the weather resistant film layer and the water vapor barrier film layer in the laminated moisture-proof sheet (2) and the water vapor transmission rate of the laminated moisture-proof sheet (2) were measured.

Example 3
Laminated moisture-proof sheet (3) in the same manner as in Example 1 except that the adhesive coating liquid (c) was used as the adhesive (I) and the adhesive coating liquid (a) was used as the adhesive (II). Was prepared, and the interlayer strength between the weather resistant film layer and the water vapor barrier film layer in the laminated moisture-proof sheet (3) and the water vapor transmission rate of the laminated moisture-proof sheet (3) were measured.

Comparative Example 1
Laminated moisture-proof sheet (4) in the same manner as in Example 1 except that the adhesive coating liquid (a) was used as the adhesive (I) and the adhesive coating liquid (a) was used as the adhesive (II). Was prepared, and the interlayer strength between the weather resistant film layer and the water vapor barrier film layer in the laminated moisture proof sheet (4) and the water vapor transmission rate of the laminated moisture proof sheet (4) were measured.

Comparative Example 2
Laminated moisture-proof sheet (5) in the same manner as in Example 1 except that the adhesive coating liquid (f) was used as the adhesive (I) and the adhesive coating liquid (f) was used as the adhesive (II). Was prepared, and the interlayer strength between the weather resistant film layer and the water vapor barrier film layer in the laminated moisture-proof sheet (5) and the water vapor transmission rate of the laminated moisture-proof sheet (5) were measured.

The sheet of Comparative Example 1 using an adhesive having a relatively high storage modulus as the adhesives (I) and (II) has a low water vapor transmission rate and an excellent water vapor barrier property, but the weather resistant film layer and the water vapor barrier The interlayer strength with the film layer is extremely low. Moreover, the sheet | seat of the comparative example 2 using the adhesive agent with comparatively low storage elastic modulus as adhesive agent (I) and (II) has sufficient interlayer intensity | strength of a weather resistance film layer and a water vapor | steam barrier film layer. However, the water vapor permeability is high and the water vapor barrier property is poor.
On the other hand, the laminated moisture-proof sheets of Examples 1 to 3 using an adhesive having a relatively low storage modulus as the adhesive (I) and an adhesive having a relatively high storage modulus as the adhesive (II) It is possible to achieve both sufficient interlayer strength and sufficient water vapor barrier properties. Accordingly, the laminated moisture-proof sheet of the present invention has excellent interlayer strength and water vapor barrier properties.

  The laminated moisture-proof sheet of the present invention has excellent interlayer strength and water vapor barrier properties. Therefore, the laminated moisture-proof sheet of the present invention can be suitably applied as a surface protection member for electronic devices such as solar cells, thereby preventing performance deterioration of electronic devices such as solar cells and durability of electronic devices. Can be improved.

Claims (7)

  It has at least five layers of a weather resistant film layer, an adhesive (I) layer, a water vapor barrier film layer, an adhesive (II) layer and a sealant layer in this order, and the water vapor barrier film layer is inorganic on one side of the substrate. An adhesive that comprises a water vapor barrier film formed by laminating thin film layers, and is a laminated moisture-proof sheet in which the surface on the inorganic thin film layer side is disposed on the weather resistant film layer side, and constitutes the adhesive (I) layer The storage elastic modulus E1 of (I) at 25 ° C., 10 Hz, and strain 0.1% is 20 MPa or less, and the adhesive (II) constituting the adhesive (II) layer has a temperature of 25 ° C., 10 Hz, strain 0. A laminated moisture-proof sheet having a storage elastic modulus E2 at 1% of 5 MPa or more and E2> E1. The laminated moisture-proof sheet according to claim 1, wherein the relationship between the storage elastic moduli E1 and E2 satisfies the following condition (1).
(E2-E1) /E2≧0.3 (1)   The laminated moisture-proof sheet according to claim 1 or 2, wherein the adhesives (I) and (II) are both polyurethane adhesives.   The adhesives (I) and (II) are both two-component adhesives, and the main agent contains at least one selected from the group consisting of polycarbonate polyols, polyether polyols, polyurethane polyols and polyester polyols. The laminated moisture-proof sheet according to any one of claims 1 to 3.   The laminated moisture-proof sheet according to any one of claims 1 to 4, wherein the base material constituting the water vapor barrier film layer is a polyester film.   The laminated moisture-proof sheet according to any one of claims 1 to 5, which is used for a surface protection member for a solar cell.   The surface protection member for solar cells which has the laminated moisture-proof sheet in any one of Claims 1-6.