JP6442879B2 - Laminated moisture barrier film - Google Patents

Description

  The present invention relates to a laminated moisture-proof film, a solar cell protective material having the laminated moisture-proof film, and a solar cell having the solar cell protective material.

A moisture-proof film (barrier film) in which an inorganic thin film such as silicon oxide is formed on the surface of a plastic film substrate has been laminated with other plastic films and used for various packaging applications. In recent years, it has been used in liquid crystal display elements, solar cells, electromagnetic wave shields, touch panels, organic electroluminescence (EL) elements, organic TFTs, organic semiconductor sensors, organic light emitting devices, electronic paper, film capacitors, inorganic EL elements, color filters, etc. It is also used for new applications such as base film and vacuum insulation.
A film obtained by laminating a moisture-proof film and another film (laminated moisture-proof film) is required to have transparency in addition to moisture resistance, for example, as a protective material for solar cells. Further, even under severe conditions such as high-temperature and high-humidity conditions, it is required that the adhesion between the moisture-proof film constituting the laminated film and the other plastic film is good for a long period of time. The films are usually bonded via an adhesive layer, and in particular, a laminated film having excellent adhesion to an inorganic thin film on a moisture-proof film has been developed.

In Patent Document 1, on the vapor deposition surface side of the inorganic oxide vapor-deposited film, 60 to 99 parts by weight of an ethylene / unsaturated carboxylic acid random copolymer and ethylene / (meth) acrylic acid ester / maleic anhydride random copolymer or A laminate having a laminated structure in which an ethylene copolymer composition composed of 40 to 1 part by weight of an ethylene / α-olefin copolymer graft-modified with maleic anhydride is laminated, and is excellent in interlayer adhesion, transparency, gas barrier properties, etc. A film is disclosed.
Patent Document 2 discloses a specific ethylene / α-olefin copolymer, polyvinyl butyral, ethylene-methyl acrylate containing a cross-linking agent on the vapor deposition surface of a film obtained by depositing an inorganic oxide on a fluorine resin film. A cover film for a solar cell is disclosed in which a filler layer formed mainly of a copolymer or a silicone resin is laminated.

JP 2000-43180 A JP 2000-91611 A

However, since the adhesive layer mainly composed of the ethylene / unsaturated carboxylic acid random copolymer disclosed in Patent Document 1 contains a carboxy group, the laminated film having the adhesive layer is long in a high-temperature and high-humidity environment. Moisture resistance after exposure to time is significantly reduced.
The filler layer disclosed in Patent Document 2 is a layer (that is, a sealing material layer) that is provided between the vapor deposition surface of the inorganic oxide and the solar cell element and has excellent embedding suitability and the like of the solar cell element. The adhesive layer that bonds the films is different in use and required characteristics. Since the filler layer is a thick film, the laminated film having such a layer is not sufficiently transparent as a film used for solar cell applications. Further, since the resin constituting the filler layer disclosed in Patent Document 2 contains a crosslinking agent, the obtained filler layer has a crosslinked structure and is not expected to exhibit thermoplasticity. The

  Moreover, the laminated moisture-proof film used for solar cell applications and the like is obtained by laminating a weather-resistant film such as a fluororesin film and a moisture-proof film via an adhesive layer. In this case, the adhesive layer is required to have good adhesion to both the weather-resistant film and the moisture-proof film. However, neither of Patent Documents 1 and 2 discloses an adhesive layer having good adhesion to a weather resistant film.

  As described above, the object of the present invention is a laminated moisture-proof film that has high transparency and can maintain excellent moisture-proof properties and adhesion between films even after storage under high-temperature and high-humidity conditions, and a sun having the laminated moisture-proof film It is providing the solar cell which has a protective material for batteries, and the said protective material for solar cells.

  As a result of intensive studies to solve the above problems, the present inventors use a resin layer having a specific composition as the adhesive layer in a laminated moisture-proof film having a weather-resistant film, an adhesive layer, and a moisture-proof film in this order. The inventors have found that the above problems can be solved, and have completed the present invention. That is, the present invention is as follows.

[1] A laminated moisture-proof film having at least a weather-resistant layer, a resin layer containing an ethylene-alkyl (meth) acrylate copolymer, and a moisture-proof layer having an inorganic layer on at least one surface of a substrate in this order.
[2] The laminated moisture-proof film according to the above [1], wherein the content of the ethylene-alkyl (meth) acrylate copolymer in the resin constituting the resin layer is 5 to 100% by mass.
[3] The laminated moisture-proof film according to the above [1] or [2], wherein the resin layer contains neither a homopolymer nor a copolymer of an unsaturated carboxylic acid compound.
[4] The laminated moisture-proof film according to any one of [1] to [3], wherein the resin layer further contains a polyolefin.
[5] The laminated moisture-proof film according to the above [4], wherein the polyolefin content in the resin constituting the resin layer is more than 0% by mass and 95% by mass or less.
[6] The resin layer and the inorganic layer are in contact with each other, and the ratio a / b between the thickness a of the resin layer and the thickness b of the inorganic layer in contact with the resin layer is in the range of 200 to 10,000. The laminated moisture-proof film according to any one of 1] to [5].
[7] The laminated moisture-proof film according to any one of [1] to [6], wherein the resin constituting the resin layer has a melt flow rate of 20 g / 10 min or less at a temperature of 190 ° C. and a load of 2.16 kg.
[8] The inorganic material constituting the inorganic layer is at least one selected from silicon oxide, silicon oxynitride, silicon nitride, aluminum oxide, and aluminum nitride, according to any one of the above [1] to [7]. Laminated moistureproof film.
[9] The laminated moisture-proof film according to any one of [1] to [8], wherein the weather-resistant layer is made of a fluororesin film.
[10] The laminated moisture-proof film according to any one of [1] to [9], wherein the substrate is a polyethylene terephthalate film or a polyethylene naphthalate film.
[11] The laminated moisture-proof film according to any one of [1] to [10], wherein a water vapor transmission rate at a temperature of 40 ° C. and a relative humidity of 90% is 0.1 [g / m ² / day] or less.
[12] The laminate according to any one of the above [1] to [11], wherein the water vapor permeability reduction degree A represented by the following formula measured at a temperature of 40 ° C. and a relative humidity of 90% is 4 or less. Moisture-proof film.
Degree of decrease in water vapor transmission rate A = (water vapor transmission rate of laminated moisture-proof film after heating at 150 ° C. for 20 minutes) / (water vapor transmission rate of laminated moisture-proof film)
[13] The laminate according to any one of the above [1] to [12], wherein the water vapor permeability reduction degree B represented by the following formula measured at a temperature of 40 ° C. and a relative humidity of 90% is 4 or less. Moisture-proof film.
Degree of decrease in water vapor transmission rate B = (water vapor transmission rate of laminated moisture-proof film after holding for 500 hours in an environment of temperature 85 ° C. and relative humidity 85%) / (water vapor transmission rate of laminated moisture-proof film)
[14] The laminated moisture-proof film according to any one of [1] to [13], wherein the light transmittance is 80% or more.
[15] A solar cell protective material having the laminated moisture-proof film according to any one of [1] to [14].
[16] A solar cell having the solar cell protective material according to [15].

  According to the present invention, a laminated moisture-proof film that has high transparency and can maintain excellent moisture-proof property and adhesion even after storage under high-temperature and high-humidity conditions, a solar cell protective material having the laminated moisture-proof film, and A solar cell having the solar cell protective material can be provided.

<Laminated moisture-proof film and solar cell protective material>
The laminated moisture-proof film of the present invention has at least a weather-resistant layer, a resin layer containing an ethylene-alkyl (meth) acrylate copolymer, and a moisture-proof layer having an inorganic layer on at least one surface of the substrate in this order. The present invention is described in further detail below.

[Weatherproof layer]
In the present invention, examples of the weather resistant layer include a weather resistant resin composition coating layer and a weather resistant film, and a weather resistant film is preferred.
In the present invention, the weather-resistant film can be used without limitation as long as it has hydrolysis resistance and weather resistance. For example, polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), Tetrafluoroethylene / hexafluoropropylene copolymer (FEP), ethylene / tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), etc. Fluorine resin; Polyester such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); Polycarbonate; Acrylic resin such as polymethyl methacrylate (PMMA); Films of various resins such as polyamide Door can be. The weather resistant film may contain two or more of these resins, or may be a laminated film of two or more films.
Among these, from the viewpoint of weather resistance and transparency, the weather resistant film is preferably a fluororesin film, and is selected from one or more selected from ethylene / tetrafluoroethylene copolymer (ETFE) and polyvinylidene fluoride (PVDF). It is more preferable that it is the fluorine resin film which becomes.

  In order to obtain the effect of reducing the residual stress in the laminated moisture-proof film at the time of high temperature and high humidity, to reduce the residual strain of the weather-resistant layer generated during the thermocompression bonding in the production of the laminated moisture-proof film of the present invention, It is preferable to use a film having a glass transition temperature of −50 to 180 ° C. By using a weather-resistant film with a glass transition temperature within the above temperature range, the molecular and crystal orientation in the film caused by the history of the force applied in the previous process and the thermal history at the temperature at the time of thermocompression bonding. It can be relaxed and residual strain can be reduced.

In addition, since it is preferable that the change in characteristics is small even during vacuum lamination in the production of laminated moisture-proof films, and in temperature and humidity changes during high temperature and high humidity, as a weather resistant film, a low shrinkage rate by prior heat treatment etc. A film subjected to the above is preferably used.
Furthermore, the weather-resistant film is a known additive such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a stabilizer such as a light stabilizer, a lubricant, a crosslinking agent, an antiblocking agent, An antioxidant etc. can be contained. Moreover, you may laminate | stack the resin layer containing these various additives.
The thickness of the weather-resistant layer is generally about 20 to 200 μm, and in the case of a weather-resistant film, 20 to 100 μm is preferable and 20 to 75 μm is more preferable from the viewpoint of ease of handling and cost.

[Dampproof layer]
The moisture-proof layer according to the present invention is a layer having at least one inorganic layer on at least one surface of the substrate, and is a layer having moisture-proof and transparency. When the laminated moisture-proof film of the present invention is used as a protective material for solar cells, it is possible to protect the inner surface side of solar cells and the like by permeation of moisture and water.
In addition, a moisture-proof layer is laminated | stacked with the above-mentioned weathering layer through the resin layer mentioned later.

As the base material used for the moisture-proof layer, a resin film is preferable, and the material is used for packaging materials such as ordinary packaging materials and electronic devices, solar cell members, electronic paper members, and organic EL members. Any resin can be used without particular limitation. 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, acrylic resin, and biodegradable resin. Among these, polyesters, polyamides, and polyolefins are preferable from the viewpoints of film properties and cost. The base material may contain two or more of these resins.
Among these, from the viewpoint of film physical properties, the substrate is preferably a polyester film, more preferably a polyethylene terephthalate (PET) film or a polyethylene naphthalate (PEN) film.

In addition, the base material 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 oxidation agent. An inhibitor or the like can be contained.
The resin film as the substrate may be unstretched or stretched.

  Such a substrate can be produced by a conventionally known method. For example, the raw material is melted by an extruder, extruded by an annular die or a T die, and rapidly cooled to be substantially amorphous and not oriented. A stretched 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 a uniaxial direction or a biaxial direction can be produced by stretching in a direction (horizontal axis) perpendicular thereto. Although a draw ratio can be set arbitrarily, the heat shrinkage rate at 100 ° C. is preferably 0.01 to 5%, more preferably 0.01 to 2%. Among these, from the viewpoint of film properties, biaxially stretched polyethylene naphthalate film, biaxially stretched polyethylene terephthalate film, coextruded biaxially stretched film of polyethylene naphthalate and polyethylene terephthalate, or coextrusion biaxially of these resins and other resins A stretched film is preferred.

  In the present invention, the thickness of the base material is preferably 10 to 150 μm, more preferably 10 to 100 μm, still more preferably 10 to 75 μm, and still more preferably 12 to 50 μm, from the viewpoint of moisture resistance of the end face of the laminated moisture-proof film. is there.

  In addition, it is preferable to provide an anchor coat layer in the said base material for the adhesive improvement with an inorganic layer. Examples of the anchor coat agent for forming the anchor coat layer include solvent-based or aqueous polyester resins, isocyanate resins, urethane resins, acrylic resins, vinyl resins, vinyl alcohol resins, and other alcoholic hydroxyl group-containing resins, vinyl butyral resins, and nitrocellulose resins. Oxazoline group-containing resin, carbodiimide group-containing resin, methylene group-containing resin, epoxy group-containing resin, styrene resin, silicone resin and the like. These can be used alone or in combination of two or more. In addition, the anchor coat layer contains a silane coupling agent, a titanium coupling agent, an alkyl titanate, an ultraviolet absorber, a stabilizer such as a weather resistance stabilizer, a lubricant, an anti-blocking agent, an antioxidant, etc., if necessary. can do.

  The thickness of the anchor coat layer is preferably 10 to 200 nm, and more preferably 10 to 150 nm, from the viewpoint of improving the adhesion with the inorganic layer. As a method for forming the anchor coat layer, a known coating method is appropriately adopted. For example, any method such as a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, and a coating method using a spray can be used. Alternatively, the substrate 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 production line (inline) or a method performed after the substrate production (offline).

  Examples of inorganic substances constituting the inorganic layer include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, and oxides, carbides, nitrides, oxycarbides, oxynitrides, oxycarbonitrides, diamond-like carbons thereof. Or a mixture thereof or the like can be mentioned. Inorganic oxides such as silicon oxide, silicon oxycarbide, silicon oxynitride, silicon oxycarbonitride, aluminum oxide, aluminum oxycarbide and aluminum oxynitride because there is no risk of leakage of current when applied to solar cells Nitride such as silicon nitride and aluminum nitride, diamond-like carbon, and mixtures thereof are preferred. In particular, silicon oxide, silicon oxycarbide, silicon oxynitride, silicon oxycarbonitride, silicon nitride, aluminum oxide, aluminum oxycarbide, aluminum oxynitride, aluminum nitride, and mixtures thereof can maintain high moisture resistance stably. Preferably, at least one selected from silicon oxide, silicon oxynitride, silicon nitride, aluminum oxide, and aluminum nitride is more preferable.

As the method for forming the inorganic layer, any method such as a vapor deposition method and a coating method can be used, but the 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 physical vapor deposition (PVD), chemical vapor deposition (CVD), atomic layer deposition (ALD) and the like. Examples of physical vapor deposition include vacuum deposition, ion plating, and sputtering. Examples of chemical vapor deposition include 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). Atomic layer deposition is performed by repeatedly adsorbing the molecules of the raw material compound on the surface of each monolayer on a substrate placed in a vacuum vessel, forming a film by reaction, and removing excess molecules by purging. It is a technique to pile up one by one.
Further, the inorganic layer may be a single layer or a multilayer, and the multilayer can be formed by using the various film forming methods mentioned above to improve moisture resistance. In that case, the same film formation method may be used, or a different film formation method may be used for each layer. However, it is effective to improve the moisture resistance and productivity by continuously performing them under reduced pressure. This is preferable.
Moreover, when an inorganic layer is a multilayer, each layer may consist of the same inorganic substance, or may consist of a different inorganic substance.

  The thickness of the inorganic layer is preferably from 5 to 1000 nm, more preferably from 10 to 800 nm, further preferably from 10 to 500 nm, still more preferably from 10 to 200 nm, from the viewpoint of high moisture-proof performance and transparency. More preferably, -200 nm.

A barrier coat layer may be further formed on the inorganic layer from the viewpoint of expressing high moisture-proof performance. The barrier coat layer plays a role of complementing fine defects of the inorganic layer, and higher moisture resistance can be expected. As the barrier coat layer, a coat layer containing an organic-inorganic hybrid material is preferably used. Specifically, polysilazane, polysiloxane, or the like is used.
The thickness of the barrier coat layer is preferably 5 to 120 nm, more preferably 10 to 90 nm, from the viewpoint of preventing the occurrence of cracks and exhibiting high moisture-proof performance. The barrier coat layer can be formed, for example, by preparing a coating solution containing the organic-inorganic hybrid material, applying the coating solution on the inorganic layer so as to have a desired thickness, and drying by heating.

The water vapor transmission rate at a moisture-proof layer temperature of 40 ° C. and a relative humidity of 90% is preferably less than 0.1 [g / m ² / day], more preferably 0.05 [g / m ² / day] from the viewpoint of moisture resistance. day] or less, and more preferably 0.03 [g / m ² / day] or less.
As described above, the adjustment of the water vapor transmission rate of the moisture-proof layer is performed by appropriately selecting the inorganic substance constituting the inorganic layer, the thickness of the inorganic layer, the thickness of the moisture-proof layer, the formation of the barrier coat layer, the oxidation number of the inorganic substance, and the like. This can be done by adjusting.
The water vapor transmission rate is measured in accordance with the conditions of JIS Z 0222 “Moisture permeability test method for moisture-proof packaging containers” and JIS Z 0208 “Moisture permeability test method for moisture-proof packaging materials (cup method)”. It is measured by the method described in the examples.

[Resin layer]
The resin layer is located between the weather-resistant layer and the moisture-proof layer, and is a layer that is softened by heating and exhibits adhesiveness. The resin layer preferably contains 50% by mass or more of the resin component, more preferably 80% by mass or more, and still more preferably 90 to 100% by mass.
In order to adhere the layers constituting the laminated moisture-proof film, a method using an adhesive or an adhesive is known. The pressure-sensitive adhesive or adhesive is generally a polymer solution obtained by adding a crosslinking agent, and is dried and cured after application to form a pressure-sensitive adhesive layer or an adhesive layer. However, since the reaction rate of the cross-linking agent does not reach 100%, unreactive groups remain in the layer, thereby reducing the moisture resistance of the laminated moisture-proof film under high temperature and high humidity conditions. Further, since the pressure-sensitive adhesive and adhesive have stickiness (tack), it is necessary to laminate the film with another film immediately after being applied to the weather-resistant layer or moisture-proof layer, and then take up the manufacturing process.
On the other hand, if the resin layer in the present invention is used, it can be cooled in a state in which the resin layer is provided on the weather-proof layer or moisture-proof layer, and the obtained laminate can be wound as it is without laminating another film. is there. Moreover, since the resin layer exhibits adhesiveness by heating it again, it is also preferable in that the other layer can be easily bonded by thermal lamination when packaging.

The resin layer in the present invention contains an ethylene-alkyl (meth) acrylate copolymer. Thereby, the laminated moisture-proof film of the present invention can maintain excellent moisture resistance even after storage under high-temperature and high-humidity conditions, and can maintain the adhesion between the weather-resistant layer and the moisture-proof layer. Furthermore, the obtained laminated moisture-proof film has high transparency.
The ethylene- (meth) alkyl acrylate copolymer used in the present invention means a polymer obtained by copolymerizing ethylene and one or more alkyl (meth) acrylates. ) It contains substantially no monomer units derived from monomers other than acrylate. “Substantially does not contain” means that monomer units other than ethylene and alkyl (meth) acrylate are less than 0.1% by mass among the monomer units constituting the copolymer.
The reason why the above effect can be obtained by including the ethylene-alkyl (meth) acrylate copolymer in the resin layer is considered as follows. When the resin layer is composed only of polyolefin such as polyethylene, sufficient adhesion cannot be obtained when the resin layer is adhered to a hydrophilic surface such as the inorganic layer described above. In particular, in solar cell applications that require long-term weather resistance and moisture resistance, it is necessary to maintain adhesion over a long period of time under various environmental tests assuming outdoor use. Moreover, since polyethylene has high crystallinity, transparency tends to be low.
In contrast, alkyl (meth) acrylate has polarity because it has an ester bond, and by copolymerizing with ethylene, the adhesion between the resin layer and the inorganic layer can be improved compared to polyethylene. In addition, high transparency can be obtained because amorphousness can be imparted.
In addition, when the resin layer contains an acidic functional group in the laminated moisture-proof film, moisture resistance after the laminated moisture-proof film is stored under high temperature and high humidity conditions is deteriorated particularly when the resin layer and the inorganic layer are in contact with each other. On the other hand, since the ethylene-alkyl (meth) acrylate copolymer does not contain an acidic functional group, the laminated moisture-proof film of the present invention can maintain excellent moisture resistance even after being stored under high temperature and high humidity conditions. .

  From the viewpoint of obtaining the above effect, the content of the monomer unit derived from the alkyl (meth) acrylate in the ethylene-alkyl (meth) acrylate copolymer is preferably relative to all the monomer units in the copolymer. It is 1 mass% or more, More preferably, it is 5-80 mass%, More preferably, it is 10-60 mass%.

The alkyl (meth) acrylate in the ethylene-alkyl (meth) acrylate copolymer preferably has 1 to 8 carbon atoms, more preferably 1 to 6 carbon atoms from the viewpoint of heat resistance and adhesion stability. Preferably, C1-C4 is still more preferable. The alkyl group may be a straight chain, may have a branched structure, or may have a cyclic structure.
Alkyl (meth) acrylate means alkyl acrylate or alkyl methacrylate, and alkyl acrylate is preferable from the viewpoint of adhesion.
Examples of the ethylene-alkyl (meth) acrylate copolymer used in the present invention include an ethylene-methyl (meth) acrylate copolymer, an ethylene-ethyl (meth) acrylate copolymer, and an ethylene-butyl (meth) acrylate copolymer. , Ethylene-methyl (meth) acrylate-butyl (meth) acrylate copolymer, ethylene-hexyl (meth) acrylate copolymer, ethylene-pentyl (meth) acrylate copolymer, ethylene-octyl (meth) acrylate copolymer, An ethylene-decyl (meth) acrylate copolymer, an ethylene-dodecyl (meth) acrylate copolymer, etc. are mentioned. These may be used alone or in combination of two or more.
Among these, from the viewpoint of heat resistance and adhesiveness, one or more selected from ethylene-methyl (meth) acrylate copolymer and ethylene-butyl (meth) acrylate copolymer are preferable, and ethylene-methyl acrylate copolymer and ethylene are preferable. 1 or more types chosen from -butyl acrylate copolymer are more preferable.

  The ethylene-alkyl (meth) acrylate copolymer may be a block copolymer or a random copolymer. Since the structural unit derived from ethylene and the structural unit derived from alkyl (meth) acrylate have different polarities, the ethylene-alkyl (meth) acrylate copolymer is expected to take a sea-island structure in the resin layer. It is preferable that the ethylene-alkyl (meth) acrylate copolymer is a random copolymer because the island structure becomes smaller and the adhesiveness becomes uniform.

  The molecular weight of the ethylene-alkyl (meth) acrylate copolymer is arbitrary, but the weight average molecular weight is preferably 5,000 to 1,000,000. When the weight average molecular weight is 5,000 or more, there is no possibility that the copolymer flows out from the layer when the resin layer containing the ethylene-alkyl (meth) acrylate copolymer is heated. If the weight average molecular weight is 1,000,000 or less, the processability is good and the thickness of the resin layer can be easily controlled. From the viewpoint of the balance between heat resistance and workability, the weight average molecular weight is more preferably from 10,000 to 100,000.

The content of the ethylene-alkyl (meth) acrylate copolymer in the resin constituting the resin layer is preferably 5 to 100% by mass, more preferably 20 to 100% by mass, and still more preferably 20 to 95% by mass. More preferably, it is 30-80 mass%, More preferably, it is 40-70 mass%. If the content of the ethylene-alkyl (meth) acrylate copolymer in the resin constituting the resin layer is 5% by mass or more, the density of the monomer units derived from the alkyl (meth) acrylate contributing to the adhesiveness is sufficient. And since uniform adhesiveness can be obtained, it can be set as the laminated moisture-proof film which has moisture-proof property and adhesiveness even after the preservation | save under high-temperature, high-humidity conditions.
In addition, in this invention, "content in resin which comprises a resin layer" means content in resin which mixed all the resin components contained in a resin layer.

The resin layer may contain a thermoplastic resin other than the ethylene-alkyl (meth) acrylate copolymer. Examples of the thermoplastic resin other than the ethylene-alkyl (meth) acrylate copolymer include polyolefin, poly (meth) acrylic acid ester, polyacrylonitrile, polyhydroxy (meth) acrylate and the like. Among these, from the viewpoint of maintaining excellent moisture resistance even after storage under high-temperature and high-humidity conditions, it is preferable to further include a polyolefin.
Examples of the polyolefin include homopolymers or copolymers of ethylene, isobutylene, and α-olefin.
Examples of the polymer include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene, polybutadiene, polyisobutylene, ethylene-α-olefin copolymer, and Examples thereof include modified polyolefins obtained by modifying these polymers. Among these, from the viewpoint of transparency, at least one selected from low density polyethylene and linear low density polyethylene is preferable, and low density polyethylene is more preferable.

Examples of the α-olefin copolymerized with ethylene in the copolymer of ethylene and α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene. 1-decene, 3-methyl-butene-1, 4-methyl-pentene-1, and the like. Of these, propylene, 1-butene, 1-hexene, and 1-octene are preferably used from the viewpoints of industrial availability, various characteristics, and economical efficiency. α-olefins may be used alone or in combination of two or more.
The α-olefin is usually 2 mol% or more, preferably 40 mol% or less, more preferably 3 to 30 mol%, still more preferably based on all monomer units in the copolymer with ethylene. 5 to 25 mol%. Within this range, the α-olefin is copolymerized to reduce the crystallinity of the copolymer, so that the transparency is improved, and problems such as blocking of raw material pellets hardly occur. Among the ethylene-α-olefin copolymers, an ethylene-α-olefin random copolymer is preferably used from the viewpoints of transparency and flexibility.

  The preferred weight average molecular weight of polyolefin is the same as that of the above-mentioned ethylene-alkyl (meth) acrylate copolymer.

  The content of the polyolefin in the resin constituting the resin layer is 95% by mass or less, preferably 80% by mass or less, and the preferred content may be more than 0% by mass, more preferably 5 to 80% by mass, More preferably, it is 20-70 mass%, More preferably, it is 30-60 mass%. If the content of the polyolefin is within the above range, the laminated moisture-proof film can maintain excellent moisture resistance even after storage under high temperature and high humidity conditions while maintaining adhesiveness. Moreover, since polyolefin is excellent in hydrolysis resistance, it is preferable that polyolefin is contained in the said range in a resin layer.

The resin layer in the present invention preferably contains neither an unsaturated carboxylic acid compound homopolymer nor a copolymer. When the content of the carboxy group in the resin layer is smaller, the moisture resistance is less deteriorated even after storage under high temperature and high humidity conditions, and excellent moisture resistance can be maintained. From the same viewpoint, the resin constituting the resin layer preferably has an acid value of 100 mgKOH / g or less, and more preferably 10 mgKOH / g or less.
Here, the unsaturated carboxylic acid compound is a concept including both a carboxylic acid compound having a polymerizable unsaturated bond or a carboxylic acid anhydride, such as acrylic acid, methacrylic acid, maleic anhydride, phthalic anhydride, and the like. And compounds having such acidic units in a part of the structure such as the main chain and side chains, that is, dimers, trimers, oligomers, and polymers.

  The resin layer preferably contains a thermoplastic resin as a main component in order to exhibit adhesiveness by heating. As a thermoplastic resin, thermoplastic resins, such as the above-mentioned ethylene-alkyl (meth) acrylate copolymer, the above-mentioned polyolefin, poly (meth) acrylic ester, polyacrylonitrile, polyhydroxy (meth) acrylate, are mentioned. These thermoplastic resins are preferably contained in the resin layer in an amount of 50% by mass or more, more preferably 80% by mass or more, and further preferably 90 to 100% by mass.

The resin constituting the resin layer preferably has a melting point of 60 to 150 ° C, more preferably 60 to 120 ° C, from the viewpoint of the selectivity of the processing temperature in the thermocompression bonding step in the production of the laminated moisture-proof film.
The resin constituting the resin layer preferably has a glass transition temperature of −20 ° C. or lower from the viewpoint of reducing the residual stress of the resin layer in the heating and cooling cycle. When the glass transition temperature is in the above range, it is possible to suppress a decrease in moisture resistance particularly in a low temperature region.

The melt flow rate (MFR) of the resin constituting the resin layer is preferably 20 g / 10 min or less at a temperature of 190 ° C. and a load of 2.16 kg. When the laminated moisture-proof film of the present invention is used as a protective material for solar cells, when producing a solar cell, a vacuum lamination process is performed at about 150 ° C. for more than ten minutes, so the performance of the protective material is in the vacuum lamination process. It is necessary not to decrease. If the MFR of the resin constituting the resin layer is 20 g / 10 min or less, the resin does not flow out from the interlayer in the vacuum lamination step, and the uniformity of the thickness of the resin layer can be maintained, so that the appearance is improved. The MFR of the resin constituting the resin layer is more preferably 18 g / 10 minutes or less, and further preferably 15 g / 10 minutes or less at a temperature of 190 ° C. and a load of 2.16 kg. Specifically, MFR can be measured by the method described in Examples.
Here, the MFR of the resin constituting the resin layer refers to an MFR of a resin obtained by mixing all the resin components contained in the resin layer.

The resin layer in the present invention may contain various additives such as an ultraviolet absorber, a light stabilizer, and an antioxidant as necessary. Especially, it is preferable to contain a ultraviolet absorber and a light stabilizer as an additive.
As an ultraviolet absorber, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-butylphenyl) benzotriazole, 2- (2- Hydroxy-5-octylphenyl) benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chlorobenzotriazole, 2- (3,5-di-tert-amyl-2- Benzotriazoles such as hydroxyphenyl) benzotriazole; benzophenone UV absorbers such as 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-4-n-octyloxybenzophenone; 2- [4,6-bis (2, 4-Dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) ) Triazine ultraviolet absorbers such as phenol, 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol; p-tert-butylphenyl salicylate, phenyl salicylate Among these salicylate-based ultraviolet absorbers, one kind or a mixture of two or more kinds can be used.
In particular, from the viewpoint of heat resistance and durability, the triazine-based UV absorber is preferably contained in an amount of 50 to 100% by mass with respect to the total amount of the UV absorber.
The compounding quantity of a ultraviolet absorber is about 0.01-2.5 mass% normally in a resin layer, Preferably it is 0.05-2.0 mass%.

As the light stabilizer, a hindered amine light stabilizer is preferably used. The hindered amine light stabilizer does not absorb ultraviolet rays like the ultraviolet absorber, but exhibits a remarkable synergistic effect when used together with the ultraviolet absorber.
Examples of the hindered amine light stabilizer include dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, poly [{6- (1,1,1, 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-hi Rokishibenjiru) -2-n-butyl malonic acid bis (1,2,2,6,6-pentamethyl-4-piperidyl) and the like. These light stabilizers can be used alone or in combination of two or more.
The compounding quantity of a light stabilizer is about 0.01-2.0 mass% normally in a resin layer, Preferably it is 0.05-1.0 mass%.

As the antioxidant, various commercial products can be used, and various types such as monophenol type, bisphenol type, polymer type phenol type, sulfur type and phosphite type can be exemplified.
Examples of monophenols include 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-4-ethylphenol, and the like. Examples of the bisphenol 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.

Examples of the high molecular phenolic group 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, tocopherol (vitamin E) and the like.
Examples of sulfur-based compounds include dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiopropionate.

  The phosphite system includes triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecyl) phosphite, Crick neopentanetetrayl bis (octadecyl phosphite), tris (mono and / or di) phenyl phosphite, diisodecyl pentaerythritol diphosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-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-10-phosphine Phenanthrene, cyclic neopentanetetraylbis (2,4-di-tert-butylphenyl) phosphite, cyclic neopentanetetraylbis (2,6-di-tert-methylphenyl) phosphite, 2,2- And methylene bis (4,6-tert-butylphenyl) octyl phosphite.

  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 both in combination. The addition amount of this antioxidant is about 0.1-1 mass% normally in a resin layer, Preferably it is 0.2-0.5 mass%.

  It is preferable that the resin layer does not substantially contain a crosslinking agent. The phrase “substantially free of crosslinking agent” means that the content of the crosslinking agent is preferably 0.1% by mass or less in the resin layer, more preferably 0.01% by mass or less, and 0.001% by mass. % Or less is more preferable.

The resin layer has a tensile storage modulus of 5 × at 100 ° C., a frequency of 10 Hz, and a strain of 0.1% in order to prevent damage to the inorganic layer by absorbing the stress generated by shrinkage of the opposing film. It is preferably 10 ⁵ Pa or less.
The resin layer preferably has a tensile storage modulus of 1 × 10 ⁷ Pa or more at 20 ° C., a frequency of 10 Hz, and a strain of 0.1% from the viewpoint of maintaining adhesive strength at normal temperature (20 ° C.).

In the present invention, the resin layer is a coating of a resin layer forming composition in which a resin constituting the resin layer and additives such as an ultraviolet absorber and a light stabilizer are mixed with an inorganic layer of a weather-resistant layer or a moisture-proof layer. It may be formed by directly coating the liquid, or the coating liquid of the resin layer forming composition is applied to the release treatment surface of the release sheet that has been subjected to the release treatment, and this is applied to the weather resistant layer or moisture proof layer. You may form by peeling a peeling sheet after bonding to an inorganic layer (coating method).
In addition, without preparing a coating liquid, the resin layer forming composition obtained by melting and kneading the resin constituting the resin layer and other additives is poured onto the weather-resistant layer or moisture-proof layer, and cooled with a cooling roll to form the resin layer. It may be formed (extrusion laminating method). Or you may shape | mold the composition for resin layer which melt-kneaded resin which comprises a resin layer, and another additive into a film form by the casting method.

The coating liquid used in the coating method is obtained by dissolving a resin layer forming composition in which an resin such as a resin layer and additives such as an ultraviolet absorber and a light stabilizer are mixed in an organic solvent, water It is preferable to use those dissolved or dispersed in. What was dissolved in the organic solvent is preferable for uses, such as a solar cell member in which water resistance is asked.
Examples of the organic solvent include toluene, xylene, methanol, ethanol, isobutanol, n-butanol, acetone, methyl ethyl ketone, ethyl acetate, tetrahydrofuran and the like. These may be used alone or in combination of two or more. For the convenience of coating, the coating liquid is preferably prepared using these organic solvents so that the solid content concentration is in the range of 10 to 50% by mass.
Coating of the coating liquid is, for example, conventionally known coating methods such as bar coating, roll coating, knife coating, roll knife coating, die coating, gravure coating, air doctor coating, doctor blade coating, etc. It can be done by a method.
After coating, a resin layer is formed by drying treatment usually at a temperature of 70 to 110 ° C. for about 1 to 5 minutes.

In the extrusion laminating method, the resin constituting the resin layer, and the resin layer forming composition obtained by melt-kneading other additives are poured onto the weather resistant film constituting the weather resistant layer or the moisture proof film constituting the moisture proof layer, etc. By cooling with a cooling roll, a laminate of a weather resistant layer and a resin layer and a laminate of a moisture-proof layer and a resin layer can be obtained. When there are a plurality of raw materials constituting the resin layer, they may be mixed by dry blending, put into an extrusion processing machine, or compounded in advance. It is more preferable to perform compounding in advance in order to improve the uniformity of the resin and improve the workability. In order to prevent thermal decomposition of the resin, it is preferable to carry out the compound at a temperature lower than the processing temperature of extrusion lamination.
Two resin layers can be stacked by pouring and cooling the resin layer forming composition again by extrusion lamination on the resin layer side of the laminate thus obtained. When the resin layers are stacked, the same resin may be used in each layer, or different resins may be used. Moreover, you may further overlap with 3 layers and 4 layers. By this method, the thickness and structure of the resin layer can be arbitrarily selected. The thickness of the resin layer provided at a time can be controlled by the discharge amount of the resin layer forming composition extruded from the die and the line speed at which the film is conveyed. The thickness of the resin layer provided at a time is preferably selected in consideration of the temperature of the resin, the spreadability, the uniformity of the layer thickness, and the productivity, and is usually 3 to 100 μm, and is 10 in terms of processing stability. ˜80 μm is preferred.
In addition, when producing the laminated body by which two resin layers were laminated | stacked by extrusion lamination, it is preferable to form a resin layer on a weather resistance film or a moisture-proof film, and to laminate | stack a resin layer further on this resin layer. . When a resin layer is further formed on the resin layer by extrusion lamination, there is no crack or optical turbidity at the interface between the resin layers, and a laminated film in which the resin layer is completely integrated can be obtained. Alternatively, one resin layer is formed on a weather-resistant film, the other resin layer is formed on a moisture-proof film, and then the resin layer on the weather-resistant film and the resin layer on the moisture-proof film face each other. You may laminate.

The resin temperature to be extruded in the extrusion laminating process is usually 150 to 350 ° C. If it is 150 degreeC or more, the flow of resin will become favorable, and if it is 350 degrees C or less, there is no possibility of thermal decomposition of resin. From the point of workability and prevention of thermal decomposition of the resin, the resin temperature is preferably 200 to 320 ° C, more preferably 260 to 300 ° C. The line speed can be arbitrarily selected according to the apparatus capability, but is usually about 10 to 200 m / min. 10 to 150 m / min is preferable from the viewpoint of processing stability, and 50 to 150 m / min is preferable from the viewpoint of productivity.
In the extrusion laminating method, films can be bonded to both sides of the resin layer at once. For example, when a resin layer is formed on a moisture-proof film constituting a moisture-proof layer, a resin is placed between the two films by feeding out the weather-resistant film constituting the weather-resistant layer from the opposite side of the moisture-proof film side of the resin layer. A laminate provided with layers can be obtained.

  The resin layer may be formed of two or more layers as described above. When the number of resin layers is two or more, the resin layer located on the weatherproof layer side contains more various additives such as the above-described ultraviolet absorber and light stabilizer than the resin layer located on the moisture proof layer side. It is preferable to contain. By comprising in this way, even when an additive bleeds out in the environment of the long-term exposure test, the degree of moisture-proof deterioration of a moisture-proof layer can be reduced. Moreover, it is more preferable that the above-mentioned various additives are contained only in the resin layer on the weather resistant layer side, and the above-mentioned various additives are not contained in the resin layer on the moisture-proof layer side.

  The thickness of the resin layer is preferably 5 to 120 μm, more preferably 10 to 100 μm, still more preferably 10 to 80 μm, and still more preferably 20 to 80 μm. If the thickness of the resin layer is 5 μm or more, sufficient adhesive force can be obtained, and if it is 120 μm or less, it is possible to prevent the moisture resistance from being increased due to an increase in stress on the inorganic layer surface of the moisture-proof layer.

Furthermore, in the laminated moisture-proof film of the present invention, the resin layer and the inorganic layer are in contact with each other, and when the resin layer thickness is a and the inorganic layer thickness is b, the resin layer thickness a and the resin layer The ratio a / b of the inorganic layer in contact with the thickness b is preferably in the range of 200 to 10,000, more preferably in the range of 250 to 9000, and still more preferably in the range of 400 to 2000. Thereby, the moisture-proof fall at the time of the thermocompression bonding of the resin layer in preparation of a laminated moisture-proof film can be suppressed. At the time of thermocompression bonding, pressure is applied in the vertical direction of the inorganic layer, and it is necessary that the moisture resistance does not deteriorate against the impact. Also, in the heating and cooling process during thermocompression bonding, when the thermoplastic resin contained in the resin layer melts and solidifies by cooling, the shrinkage stress damages the inorganic layer in contact with the resin layer, reducing moisture resistance It is necessary not to. If a / b is 200 or more, the thickness of the resin layer relative to the thickness of the inorganic layer is not too small, and there is no concern of damaging the inorganic layer due to insufficient impact resistance. On the other hand, if a / b is 10,000 or less, the shrinkage stress applied to the inorganic layer in contact with the resin layer does not become excessive, and a decrease in moisture resistance can be suppressed.
Further, when the thickness of the substrate used for the moisture-proof layer is c, the ratio a / c between the thickness a of the resin layer and the thickness c of the substrate is preferably in the range of 0.1 to 8. . If a / c is 0.1 or more, the initial adhesion between the weather-resistant layer and the moisture-proof layer is improved. When a / c is 8 or less, deformation of the base material due to shrinkage of the resin layer hardly occurs during thermocompression bonding (vacuum lamination) in the production of a laminated moisture-proof film. As for a / c, the range of 0.1-3.3 is more preferable, and the range of 0.2-2.0 is still more preferable.

The laminated moisture-proof film of this invention should just have the weather-proof layer, resin layer, and moisture-proof layer which were mentioned above in order, and also may have layers other than the above. Two or more resin layers and moisture-proof layers may be laminated.
When the moisture-proof layer has an inorganic layer only on one side of the substrate, the moisture-proof layer is preferably laminated with the surface on the inorganic layer side as the resin layer side.
Although the total thickness of the laminated moisture-proof film of the present invention can be appropriately selected depending on the use and the like, it is preferably 25 to 500 μm, more preferably 40 to 350 μm, and still more preferably 50 to 300 μm.

The laminated moisture-proof film of the present invention preferably has a water vapor transmission rate of 0.1 [g / m ² / day] or less, more preferably 0.05 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%. Hereinafter, more preferably 0.03 [g / m ² / day] or less.
Further, the laminated moisture-proof film of the present invention has a water vapor permeability decrease degree A of 4 or less, more preferably 3 or less, more preferably, measured by a temperature of 40 ° C. and a relative humidity of 90%. May be 2.5 or less, more preferably less than 2.0.
Degree of decrease in water vapor transmission rate A = (water vapor transmission rate of laminated moisture-proof film after heating at 150 ° C. for 20 minutes) / (water vapor transmission rate of laminated moisture-proof film)
Here, the water vapor transmission rate of the laminated moisture-proof film after being heated at 150 ° C. for 20 minutes means that the produced laminated moisture-proof film is further heated at a temperature of 150 ° C. for 20 minutes, and then the temperature is 40 ° C. and the relative humidity is 90%. The water vapor transmission rate measured in
The closer the value of the degree A of water vapor transmission rate decrease to 1, the more the moisture-proof laminated film of the present invention can maintain moisture resistance even if it is heated after production.

Further, the laminated moisture-proof film of the present invention preferably has a water vapor permeability reduction degree B represented by the following formula measured at a temperature of 40 ° C. and a relative humidity of 90%, preferably 4 or less, more preferably 3 or less, still more preferably. It can be 2.5 or less.
Degree of decrease in water vapor transmission rate B = (water vapor transmission rate of laminated moisture-proof film after holding for 500 hours in an environment of temperature 85 ° C. and relative humidity 85%) / (water vapor transmission rate of laminated moisture-proof film)
The accelerated test (hereinafter also referred to as “dump heat test”) for holding the laminated moisture-proof film of the present invention for 500 hours in an environment of 85 ° C. and 85% relative humidity is performed by a method according to JIS C 60068-3-4. Specifically, it can be carried out by the method described in the examples.
The water vapor permeability of each film in the present invention can be evaluated according to various conditions of JISZ0222 “moisture-proof packaging container moisture permeability test method” and JISZ0208 “moisture-proof packaging material moisture permeability test method (cup method)”. Specifically, it is measured by the method described in the examples.

  The laminated moisture-proof film of the present invention can have an interlayer strength between the weather-resistant layer and the moisture-proof layer of 5 N / 15 mm or more, preferably 10 N / 15 mm or more. The reduction rate of the interlayer strength after the dump heat test with respect to the initial interlayer strength can be 60% or less, preferably 50% or less. Specifically, the interlayer strength and the interlayer strength reduction rate of the laminated moisture-proof film are measured by the methods described in the examples.

  The laminated moisture-proof film of the present invention can have a light transmittance of 80% or more, preferably 85% or more. Further, the haze can be 20% or less, preferably 15% or less. Specifically, the light transmittance and haze of the laminated moisture-proof film are measured by the methods described in Examples.

[Method for producing laminated moisture-proof film]
There is no restriction | limiting in particular in the manufacturing method of the laminated moisture-proof film of this invention, A well-known method can be used. For example, the method of laminating | stacking the weather resistance layer mentioned above, a resin layer, and a moisture-proof layer in order, and performing thermocompression bonding etc. is mentioned.
Examples of the method for forming the resin layer include the aforementioned coating method and extrusion lamination method.

  The laminated moisture-proof film of the present invention is used for solar cell members, organic EL members, electronic paper surface protection members, and the like, particularly for solar cell protection materials, preventing deterioration of power generation elements due to moisture permeation, It is preferable because rusting of internal conductors and electrodes can be prevented, and the retention of electromotive force over a long period can be achieved without being affected by environmental fluctuations.

<Protective material for solar cells>
The protective material for solar cells of the present invention has the laminated moisture-proof film of the present invention, and the laminated moisture-proof film of the present invention can be used as it is as a protective material for solar cells.
Moreover, the protective material for solar cells of the present invention may be a sealing material / front surface protective material integrated type formed by laminating sealing materials. By laminating the sealing material in advance, it is possible to reduce the work of individually laminating the back surface protection material, sealing material, power generation element, sealing material, and front surface protection material in the vacuum lamination process, and increase the efficiency of solar cell module manufacturing. Can be achieved.

<Solar cell>
The solar cell of the present invention has the above-described solar cell protective material of the present invention. That is, the solar cell protective material of the present invention is laminated with other solar cell members such as a sealing material and a solar cell. By using the solar cell protective material of the present invention, the solar cell of the present invention can not only achieve a good appearance but also prevent a decrease in power generation efficiency.

A solar cell module can be produced by using the solar cell protective material of the present invention in a layer configuration of a surface protective 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, various types can be exemplified, and preferably, when the solar cell protective material of the present invention is used as a front surface protective material, a sealing material, a solar cell element, And a solar cell module manufactured using a back surface protective material. Specifically, the front surface protective material (protective material for solar cell of the present invention) / sealing material (sealing resin layer) / solar cell element / Sealing material (sealing resin layer) / back surface protection material, sealing material and front surface protection material (solar cell protection according to the present invention) on the solar cell element formed on the inner peripheral surface of the back surface protection material Material), a solar cell element formed on the inner peripheral surface of the front protective material (solar cell protective material of the present invention), for example, an amorphous solar cell element on a fluororesin-based transparent protective material Sealing material and back surface protection material on what was produced by sputtering etc. And the like can be mentioned, such as to form structure. It is optional to attach a glass plate to the outside of the solar cell protective material of the present invention as the front protective material.
In addition, when using the above-mentioned sealing material / front protective material integrated front protective material, the sealing material may not be used in some cases.

  Examples of solar cell elements include single crystal silicon type, polycrystalline silicon type, amorphous silicon type, gallium-arsenic, copper-indium-selenium, copper-indium-gallium-selenium, cadmium-tellurium, etc. II-VI group compound semiconductor type, dye-sensitized type, organic thin film type and the like can be mentioned.

  About each other member which comprises the solar cell of this invention, it does not specifically limit, For example, ethylene-vinyl acetate copolymer (EVA) and polyethylene are mentioned as a sealing material.

  When the solar cell protective material of the present invention is used as a front surface protective material, any known back surface protective material can be used, for example, a single layer such as an inorganic material or various thermoplastic resin films, or the like. A multilayer sheet may be mentioned. Examples of the inorganic material include metals such as tin, aluminum, and stainless steel and glass, and examples of the thermoplastic resin film include a polyester film, an inorganic material-deposited polyester film, a fluorine-containing resin film, and a polyolefin film. Moreover, when using the protective material for solar cells of the present invention as a back surface protective material, any known front surface protective material can be used, for example, a single layer or a multilayer such as glass or a thermoplastic resin film. A sheet or a laminated sheet of these is mentioned. Examples of the thermoplastic resin film include a polyester film, an inorganic material-deposited polyester film, a fluorine resin film, a polyolefin film, and a laminated sheet thereof.

  In the solar cell module of the present invention, the above upper and / or lower members and the surface of the solar cell protective material of the present invention have a primer for improving the adhesiveness to the sealing material and other members. Known surface treatments such as treatment and corona treatment can be applied.

The solar cell produced using the solar cell protective material of the present invention is as described above for the front protective material (solar cell protective material of the present invention) / sealing material / solar cell element / sealing material / back surface protective material. An example of a simple configuration will be described. The solar cell protective material, sealing material, solar cell element, sealing material, and back surface protective material of the present invention are laminated in order from the solar light receiving side, and a junction box (solar cell) is further formed on the bottom surface of the back surface protective material. A terminal box for connecting wiring for taking out electricity generated from the element 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.
In the above description, for example, the notation A / B / C indicates that layers are stacked in the order of A, B, and C from the bottom (or from the top).

As a manufacturing method of the solar cell, a known manufacturing method can be applied, and it is not particularly limited, but in general, the solar cell protective material, the sealing material, the solar cell element, and the sealing material of the present invention. And a step of laminating the back surface protective material in this order, and a step of vacuum-sucking them and thermocompression bonding them. Specifically, each of the above members is laminated in order, and according to a conventional method, the temperature is preferably 130 to 180 ° C., more preferably 130 to 150 ° C., the deaeration time is 2 to 15 minutes, and the press pressure is a vacuum laminator. Of 0.05 to 0.1 MPa, and the pressing time is preferably 8 to 45 minutes, more preferably 10 to 40 minutes.
In the above manufacturing method, batch-type manufacturing equipment, roll-to-roll manufacturing equipment, and the like can also be applied.

  The solar cell produced using the solar cell protective material of the present invention is a small solar cell typified by a mobile device, a large size installed on a roof or a rooftop, regardless of the type and module shape of the applied solar cell. It can be applied to various uses, such as solar cells, both indoors and outdoors. In particular, among electronic devices, use in a flexible solar cell such as a compound power generation element solar cell or an amorphous silicon type is preferred because high moisture resistance is required.

  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. Various physical properties were measured and evaluated as follows.

(MFR)
The MFR of the resin constituting the resin layer was measured at a temperature of 190 ° C. and a load of 2.16 kg according to JIS K7210.

[Accelerated test]
(1) Dump heat (DH) test The laminated moisture-proof films prepared in Examples and Comparative Examples were cut into 15 cm × 15 cm squares. 15 cm x 15 cm square sealing material (ethylene-vinyl acetate copolymer (EVA), manufactured by Mitsui DuPont Polychemical Co., Ltd., thickness 500 μm), 10 cm x 10 cm square on 3 mm thick 15 cm x 15 cm square white plate glass A release film (Teflon (registered trademark), manufactured by Mitsui DuPont Fluorochemical Co., Ltd., thickness 50 μm) is sequentially laminated, and the laminated moisture-proof film of 15 cm × 15 cm square is formed on the film. Lamination was performed so that the material side was in contact with the release film. Using a vacuum laminator (trade name: LM30 × 30, manufactured by NPC Corporation), vacuum lamination was performed at 150 ° C. for 20 minutes and a pressure of 0.1 MPa to prepare a sample for dump heat test. Obtained.
Using the temperature and humidity controller (trade name: PH-3KT, manufactured by ESPEC Co., Ltd.) according to a method in accordance with JIS C 60068-3-4, the test sample was subjected to a temperature of 85 ° C. and a relative humidity of 85%. For 500 hours.
After 500 hours, a test sample was taken out, and the inside of the release film was cut out with a cutter to take out a 10 cm × 10 cm square laminated moisture-proof film. The film was allowed to stand for 1 day in an environment of a temperature of 25 ° C. and a relative humidity of 50%, and cured to obtain a laminated moisture-proof film after the dump heat test.

[Evaluation of the physical properties]
(2) Interlaminar strength and rate of decrease in interlaminar strength of laminated moisture-proof film The laminated moisture-proof film was cut into strips having a width of 15 mm, and using a tensile tester (trade name: STA-1150, manufactured by Orientec Co., Ltd.) : 300 mm / min, tensile direction: 180 degree | times, the interlayer intensity | strength (N / 15mm) of a weather resistance film and a moisture proof film was measured.
The measurement was performed before and after the dump heat test.
Moreover, how much the interlayer strength after the dump heat test was reduced with respect to the interlayer strength (initial interlayer strength) of the laminated moisture-proof film was determined by the following formula as an interlayer strength reduction rate (%).
Interlaminar strength reduction rate (%) = [1− (interlayer strength of laminated moisture-proof film after dump heat test) / (interlayer strength of laminated moisture-proof film)] × 100

(3) Moisture resistance (water vapor transmission rate) and degree of decrease in water vapor transmission rate <Moisture resistance (water vapor transmission rate)>
The moisture-proof properties of the moisture-proof films used in Examples and Comparative Examples and the laminated moisture-proof films prepared in Examples and Comparative Examples are JIS Z 0222 “Method of testing moisture permeability of moisture-proof packaging containers” and JIS Z 0208 “of moisture-proof packaging materials. According to the conditions of “moisture permeability test method (cup method)”, the water vapor transmission rate was determined and evaluated by the following method.
Using two 10cm x 10cm square moisture-proof films or laminated moisture-proof films, with the inorganic layer forming surface (the surface on the weatherproof layer side in the laminated moisture-proof film) facing outside, about 20g of anhydrous calcium chloride as a moisture absorbent A bag with four sides sealed was prepared. The bag is placed in a constant temperature and humidity apparatus at a temperature of 40 ° C. and a relative humidity of 90%, and the mass is measured until about 200 days at intervals of 72 hours or more. The slope of the regression line between the elapsed time after the fourth day and the bag mass is measured. Water vapor transmission rate [g / m ² / day] was calculated from the water vapor transmission rate of the moisture-proof film or laminated moisture-proof film.

<Degree of decrease in water vapor transmission rate A>
The laminated moisture-proof films prepared in Examples and Comparative Examples were cut into 15 cm × 15 cm squares. A 15 cm × 15 cm square sealing material (ethylene-vinyl acetate copolymer (EVA), manufactured by Mitsui DuPont Polychemical Co., Ltd., thickness 450 μm) on a 3 mm thick 15 cm × 15 cm square white plate glass, 10 cm square separation A mold film (Teflon (registered trademark), manufactured by Mitsui DuPont Fluorochemical Co., Ltd., thickness 50 μm) is laminated in order, and the laminated moisture-proof film of 15 cm × 15 cm square is separated on the substrate side of the moisture-proof film. It laminated | stacked so that the film for type | molds might touch. This was subjected to vacuum lamination using a vacuum laminator (trade name: LM30 × 30, manufactured by NPC Corporation) at a temperature of 150 ° C. for 20 minutes and a pressure of 0.1 MPa.
The inside of the release film was cut out with a cutter, and a 10 cm × 10 cm square laminated moisture-proof film was taken out. The film was allowed to stand for 1 day in an environment of a temperature of 25 ° C. and a relative humidity of 50% for curing. This laminated moisture-proof film was designated as “a laminated moisture-proof film after being heated at a temperature of 150 ° C. for 20 minutes”.
Using each of the two laminated moisture-proof films, the water vapor transmission rate was measured by the same method as described above. The degree A of decrease in water vapor transmission rate was obtained from the following equation.
Degree of decrease in water vapor transmission rate A = (water vapor transmission rate of laminated moisture-proof film after heating at 150 ° C. for 20 minutes) / (water vapor transmission rate of laminated moisture-proof film)

<Degree B of water vapor transmission rate>
The water vapor transmission rate was measured in the same manner as described above using two laminated moisture-proof films each having a 10 cm × 10 cm square after the dump heat test. The degree B of decrease in water vapor transmission rate was obtained from the following equation.
Degree of decrease in water vapor transmission rate B = (water vapor transmission rate after dump heat test of laminated moisture-proof film) / (water vapor transmission rate of laminated moisture-proof film)

(4) Light transmittance, haze value A laminated moisture-proof film is cut into 5 cm × 5 cm square, and a method based on JIS K 7361-1 is used using a haze meter (trade name: NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.). The light transmittance and haze value were measured.

[Structure film]
<Weather-resistant film>
A 2-ethylene-4-fluoroethylene copolymer (ETFE) film (manufactured by Asahi Glass Co., Ltd., trade name: AFLEX 50NT1250DCS, thickness 50 μm) was used as a weather resistant film.

<Moisture-proof film having an inorganic layer on the substrate>
(Dampproof film 1)
A biaxially stretched polyethylene terephthalate film (product name: CI800, manufactured by KOLON) having a thickness of 50 μm is used as a base material, and the following coating solution is applied to the corona-treated surface and dried to form an anchor coat having a thickness of 0.1 μm. A layer was formed.
Next, SiO was heated and evaporated under a vacuum of 1.33 × 10 ⁻³ Pa (1 × 10 ⁻⁵ Torr) using a vacuum deposition apparatus, and SiOx having a thickness of 50 nm (x = 1. 5) A moisture-proof film 1 having an inorganic layer was obtained. The water vapor transmission rate of the produced moisture-proof film 1 at a temperature of 40 ° C. and a relative humidity of 90% was 0.02 [g / m ² / day].

(Coating solution)
Polyvinyl alcohol resin (manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: “GOHSENOL”, degree of saponification: 97.0 to 98.8 mol%, degree of polymerization: 2400) was added to 2810 g of ion-exchanged water and dissolved by heating. To the mixture, 645 g of 35 mol% hydrochloric acid was added while stirring at 20 ° C. 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.
In addition, an isocyanate resin (manufactured by Sumitomo Bayer Urethane Co., Ltd., trade name: “Sumijour N-3200”) was used as a crosslinking agent, and mixing was performed so that the equivalent ratio of isocyanate groups to hydroxyl groups was 1: 2.

(Dampproof film 2)
A moisture-proof film 2 was obtained in the same manner as the moisture-proof film 1 except that a 125 μm-thick biaxially stretched polyethylene terephthalate film (manufactured by KOLON, trade name: CI800) was used as the substrate. The produced moisture-proof film 2 had a water vapor transmission rate of 0.02 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Dampproof film 3)
A moisture-proof film 3 was obtained in the same manner as the moisture-proof film 1 except that a biaxially stretched polyethylene naphthalate film having a thickness of 12 μm (trade name: Q51C, manufactured by Teijin DuPont Films Ltd.) was used as the substrate. . The moisture-proof film 3 produced had a water vapor transmission rate of 0.01 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Dampproof film 4)
A SiON film was formed by reactive sputtering using a Si target under a vacuum of 0.3 Pa (2.26 × 10 ⁻³ Torr) using a vacuum deposition apparatus, and a thickness of 25 nm was formed on the anchor coat layer. The moisture-proof film 4 was obtained in the same manner as the moisture-proof film 1 except that the SiON inorganic layer was formed. The moisture-proof film 4 produced had a water vapor transmission rate of 0.004 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Dampproof film 5)
An AlO film was formed by reactive sputtering using an Al target under a vacuum of 0.3 Pa (2.26 × 10 ⁻³ Torr) using a vacuum deposition apparatus, and a thickness of 25 nm was formed on the anchor coat layer. A moisture-proof film 5 was obtained in the same manner as the moisture-proof film 1 except that an AlOx (x = 1.4) inorganic layer was formed. The moisture-proof film 5 produced had a water vapor transmission rate of 0.004 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Dampproof film 6)
A moisture-proof film 6 was obtained in the same manner as the moisture-proof film 1 except that the thickness of the SiOx (x = 1.5) inorganic layer was 15 nm. The water vapor transmission rate of the produced moisture-proof film 6 at a temperature of 40 ° C. and a relative humidity of 90% was 0.02 [g / m ² / day].

(Dampproof film 7)
The moisture-proof film 7 was obtained by the same method as the moisture-proof film 1 except that the thickness of the SiOx (x = 1.5) inorganic layer was 90 nm. The produced moisture-proof film 7 had a water vapor transmission rate of 0.02 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Dampproof film 8)
The moisture-proof film 8 was obtained by the same method as the moisture-proof film 1 except that the thickness of the SiOx (x = 1.5) inorganic layer was 40 nm. The moisture-proof film 8 produced had a water vapor transmission rate of 0.02 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Moisture-proof film 9)
A moisture-proof film 9 was obtained in the same manner as the moisture-proof film 1 except that the thickness of the SiOx (x = 1.5) inorganic layer was 120 nm. The produced moisture-proof film 9 had a water vapor transmission rate of 0.02 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

(Moisture-proof film 10)
The moisture-proof film 10 was obtained by the same method as the moisture-proof film 1 except that the thickness of the SiOx (x = 1.5) inorganic layer was 5 nm. The moisture-proof film 10 produced had a water vapor transmission rate of 0.02 [g / m ² / day] at a temperature of 40 ° C. and a relative humidity of 90%.

In the following examples and comparative examples, the following materials were used. In addition, all the copolymerization ratios shown below are mass ratios.
-Ethylene-butyl acrylate (EBA) copolymer ARKEMA, trade name: Lotryl 35BA40 (ethylene-butyl acrylate copolymer ratio 65/35), ARKEMA, trade name: 30BA02 (ethylene-butyl acrylate copolymer ratio) 70/30) and ethylene-methyl acrylate (EMA) copolymer made by Nippon Polyethylene Co., Ltd., trade name: Lexpearl EB240H (ethylene-methyl acrylate copolymer ratio 80/20) )
・ Low density polyethylene Nippon Polyethylene Corporation, trade name: Kernel (registered trademark) KC452T
・ Ethylene-methacrylic acid (EMAA) copolymer Mitsui ・ DuPont Polychemical Co., Ltd., trade name: Nucrel N1108C (ethylene-methacrylic acid copolymer ratio 89/11)
・ Ethylene-ethyl acrylate-maleic anhydride (E / EA / MAH) copolymer ARKEMA, trade name: BONDINE AX8390 (E / EA / MAH copolymerization ratio 69/29/2)

Example 1
An ethylene-butyl acrylate (EBA) copolymer and an ethylene-methyl acrylate (EMA) copolymer were mixed at a mass ratio of 50/50. Triazine-based ultraviolet absorber (trade name: Tinuvin 1600, manufactured by BASF) is 1.5% by mass with respect to the total amount of the resin, and hindered amine light stabilizer (trade name: Chimassorb 2020FDL) is 0% with respect to the total amount of the resin. Then, 5% by mass was mixed and melt-kneaded at 170 ° C. using a T-die extrusion molding machine (manufactured by Soken). This was cast and formed into a film having a thickness of 40 μm to produce a thermoplastic resin film for forming a resin layer.
A thermoplastic resin film is laminated on the inorganic layer surface of the moisture-proof film 1, and further a weather-resistant film is laminated thereon, and a vacuum laminator (trade name: LM30 × 30, manufactured by NPC Corporation) is used. Then, thermocompression bonding was performed under the conditions of 100 ° C., 5 minutes, and pressure of 0.1 MPa to obtain a laminated moisture-proof film. Various evaluation was performed using the obtained laminated moisture-proof film. The results are shown in Table 1. The initial moisture vapor transmission rate of the laminated moisture-proof film at a temperature of 40 ° C. and a relative humidity of 90% was 0.02 [g / m ² / day].

Examples 2-5
A laminated moisture-proof film was prepared in the same manner as in Example 1 except that the resin composition and thickness of the thermoplastic resin film for forming the resin layer were changed as shown in Table 1, and various evaluations were performed. The results are shown in Table 1.

Example 6
A laminated moisture-proof film was produced in the same manner as in Example 1 except that the moisture-proof film 1 was changed to the moisture-proof film 2, and various evaluations were performed. The results are shown in Table 1.

Examples 7-9
A laminated moisture-proof film was prepared in the same manner as in Example 1 except that the resin composition and thickness of the thermoplastic resin film for forming the resin layer were changed as shown in Table 1, and various evaluations were performed. The results are shown in Table 1.

Examples 10-20
Except having changed the moisture-proof film 1 into the moisture-proof films 2-10, respectively, and having changed the resin composition and thickness of the thermoplastic resin film for resin layer formation as shown in Table 1, it carried out similarly to Example 1. A laminated moisture-proof film was prepared and subjected to various evaluations. The results are shown in Table 1.

Comparative Example 1
A laminated film was prepared in the same manner as in Example 4 except that a biaxially stretched polyethylene terephthalate film (made by KOLON, trade name: CI800) having a thickness of 50 μm was used instead of the moisture-proof film 1, and various evaluations were made. went. The results are shown in Table 1.

Comparative Example 2
A laminated film was produced in the same manner as in Example 1 except that the resin composition of the thermoplastic resin film for forming the resin layer was changed as shown in Table 1, and various evaluations were performed. The results are shown in Table 1.

Comparative Example 3
On the surface of the inorganic layer of the moisture-proof film 1, the following adhesive coating solution 1 was adjusted as an adhesive layer to a solid content of 40%, and applied and dried to a solid content of 36 g / m ² to form a polyurethane adhesive layer having a thickness of 30 μm. A weather resistant film was laminated on the polyurethane adhesive layer, cured at 40 ° C. for 5 days to produce a laminated film, and various evaluations were performed. The results are shown in Table 1.
(Preparation of adhesive coating solution 1)
As a main component containing a polycarbonate polyol component, a polycaprolactone polyol having an average molecular weight of 2000 (manufactured by Daicel Chemical Industries, trade name “Placcel 210N”), a polycarbonate diol having an average molecular weight of 500 (trade name “manufactured by Daicel Chemical Industries, Ltd.”) Plaxel CD CD205 "), and mixed so that the mass ratio of polycaprolactone polyol / polycarbonate diol is 60/40, dissolved in ethyl acetate, and has a solid content of about 50 mass% and a viscosity of 400 [mPa · s]. A polyol solution was obtained. In this polyol solution, Sumidur N3300 (manufactured by Sumika Bayer Urethane Co., Ltd.) was blended as a curing component so that the mass ratio was 10 / 0.5, and acetic acid was added so that the solid content concentration was 35% by mass. The adhesive coating liquid 1 was prepared by diluting with ethyl.

Comparative Examples 4-5
A laminated film was produced in the same manner as in Example 1 except that the resin composition of the thermoplastic resin film for forming the resin layer was changed as shown in Table 1, and various evaluations were performed. The results are shown in Table 1.

  According to the present invention, a laminated moisture-proof film that has high transparency and can maintain excellent moisture-proof property and adhesion even after storage under high-temperature and high-humidity conditions, a solar cell protective material having the laminated moisture-proof film, and A solar cell having the solar cell protective material can be provided.

Claims (15)

At least a weatherproof layer, a resin layer containing an ethylene-alkyl (meth) acrylate copolymer, and a moisture-proof layer having a moisture-proof layer having an inorganic layer on at least one surface of a substrate having a thickness of 50 to 150 μm in this order. The content of the ethylene-alkyl (meth) acrylate copolymer in the resin constituting the resin layer is 50% by mass or more, and the resin layer comprises a homopolymer and a copolymer of an unsaturated carboxylic acid compound. A laminated moisture-proof film that does not contain any polymer. The laminated moisture-proof film according to claim 1, wherein the content of the ethylene-alkyl (meth) acrylate copolymer in the resin constituting the resin layer is 50 to 100% by mass. The laminated moisture-proof film according to claim 1 or 2 , wherein the resin layer further contains a polyolefin. The laminated moisture-proof film according to claim 3 , wherein the content of polyolefin in the resin constituting the resin layer is more than 0 mass% and 50 mass% or less. Wherein in contact with the resin layer and the inorganic layer, and the thickness a of the resin layer, the ratio a / b between the thickness b of the inorganic layer in contact with the resin layer is in the range of 200 to 10,000, according to claim 1-4 The laminated moisture-proof film according to any one of the above. The laminated moisture-proof film according to any one of claims 1 to 5 , wherein a resin constituting the resin layer has a melt flow rate of 20 g / 10 min or less at a temperature of 190 ° C and a load of 2.16 kg. The laminated moisture-proof film according to any one of claims 1 to 6 , wherein the inorganic substance constituting the inorganic layer is at least one selected from silicon oxide, silicon oxynitride, silicon nitride, aluminum oxide, and aluminum nitride. . The laminated moisture-proof film according to any one of claims 1 to 7 , wherein the weather-resistant layer is made of a fluorine resin film. The laminated moisture-proof film according to any one of claims 1 to 8 , wherein the substrate is a polyethylene terephthalate film or a polyethylene naphthalate film. The laminated moisture-proof film according to any one of claims 1 to 9, wherein a water vapor transmission rate at a temperature of 40 ° C and a relative humidity of 90% is 0.1 [g / m ² / day] or less. The laminated moisture-proof film according to any one of claims 1 to 10 , wherein a degree A of reduction in water vapor transmission rate represented by the following formula, measured at a temperature of 40 ° C and a relative humidity of 90%, is 4 or less.
Degree of decrease in water vapor transmission rate A = (water vapor transmission rate of laminated moisture-proof film after heating at 150 ° C. for 20 minutes) / (water vapor transmission rate of laminated moisture-proof film) The laminated moisture-proof film according to any one of claims 1 to 11 , wherein a water vapor permeability reduction degree B represented by the following formula measured at a temperature of 40 ° C and a relative humidity of 90% is 4 or less.
Degree of decrease in water vapor transmission rate B = (water vapor transmission rate of laminated moisture-proof film after holding for 500 hours in an environment of temperature 85 ° C. and relative humidity 85%) / (water vapor transmission rate of laminated moisture-proof film) The laminated moisture-proof film according to any one of claims 1 to 12 , wherein the light transmittance is 80% or more. Protective material for a solar cell having a laminated moistureproof film according to any one of claims 1 to 13. A solar cell comprising the solar cell protective material according to claim 14 .