JP2012158154A - Transparent laminated moisture-proof film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent laminated moisture-proof film not deteriorated in moisture-proofness and inter-layer strength over a long time period and excellent in flexibility and moisture-proofness with respect to the durability of the transparent laminated moisture-proof film having a plastic film applied to a moisture-proof film having an inorganic thin film layer and a moisture permeability of 0.1 [g/m/day] or lower via a specific adhesive or a tacking agent.SOLUTION: The transparent laminated moisture-proof film has the transparent moisture-proof film having the inorganic thin film layer on at least one surface of its base material and the moisture permeability of 0.1 [g/m. day] or lower, and the plastic film disposed on a surface of the inorganic thin film layer of the transparent moisture-proof film via the adhesive layer or the tacking agent layer of at least 1×10[Pa] and not more than 5×10[Pa] in a tensile storage modulus at 100°C and at least 13 μm in thickness.

Description

  The present invention relates to a transparent laminated moisture-proof film used for an electronic device such as a solar battery, and in particular, an excellent transparent laminated film that maintains moisture resistance and interlayer strength even under high temperature conditions when incorporated in an electronic device such as a solar battery module. It relates to a moisture-proof film.

A moisture-proof 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 has been 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 and vacuum heat insulating material used in the industry.
In these applications, more demanding performance has been demanded for laminated moisture-proof films, and development of excellent laminated moisture-proof films with little deterioration of moisture resistance under long-term use and high-temperature conditions has been made.

For example, in Patent Document 1, a polyester adhesive is used for a moisture-proof film having a water vapor transmission rate of 0.22 [g / m ² · day] based on a biaxially stretched polyester film, and the weather resistance on the inorganic vapor deposition surface side. A solar cell protective material is made by pasting a polyester film and a polypropylene film on the back, and the moisture resistance after a 1000 hour test is evaluated at 85 ° C. and 85% humidity, and a proposal for preventing moisture degradation is made. .
Moreover, in the Example of patent document 2, a polyurethane adhesive layer is provided on both sides of a moisture-proof film having a water vapor transmission rate of 1 to 2 [g / m ² · day] based on a biaxially stretched polyester film, Laminated weather-resistant polyester film on both sides to produce a solar cell surface protection material, evaluated barrier performance and interlayer strength after 1000 hours of acceleration test at 85 ° C and 85% humidity, and proposed to prevent deterioration of both properties Is doing.
In Patent Document 3, a PVF film is pasted on a moisture-proof film having a water vapor transmission rate of 0.5 [g / m ² · day], which is also based on a biaxially stretched polyester film, using a two-component curable polyurethane adhesive. After the combination, the moisture resistance and interlayer strength before and after the pressure cooker test (PCT) (severe environmental test by high temperature and pressure, 105 ° C., 92 hours) are evaluated, and a proposal for preventing deterioration of the characteristics is made.

JP 2007-150084 A JP 2009-188072 A JP 2009-49252 A

However, each of the techniques disclosed in Patent Documents 1 to 3 relates to a laminate having a moisture-proof film having a water vapor transmission rate of 0.1 [g / m ² · day] or more, and has higher moisture resistance. When applied to solar cell surface protection materials such as compound power generation element solar cell modules that require high performance, moisture resistance after accelerated durability tests such as the pressure cooker test (PCT) is not sufficiently maintained. There wasn't.
The laminated moisture-proof film is excellent in moisture-proof property and interlayer strength, and it is desired that the moisture-proof property and interlayer strength are maintained for a long time. To date, the water vapor transmission rate has been 0.1 [g / m ^2. In the case of using a film having a high moisture resistance of less than [day], no actual proposal has been made to prevent the moisture resistance and the decrease in interlayer strength.

That is, an object of the present invention is to provide a moisture-proof film having an inorganic thin film layer on one surface of the substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day], the inorganic thin film layer surface of the moisture-proof film, With regard to the durability of the transparent laminated moisture-proof film having a plastic film to be bonded via a specific adhesive or pressure-sensitive adhesive, a transparent laminated moisture-proof film excellent in flexibility and moisture resistance that does not deteriorate the moisture resistance and interlayer strength over the long term An object of the present invention is to provide a surface protection material for a highly moisture-proof solar cell that is effective to prevent deterioration of the performance of an electronic device such as a solar cell and to improve the durability of the solar cell.

As a result of repeated studies, the inventors of the present invention have found that the water vapor permeability having an inorganic thin film layer on at least one surface of the substrate is less than 0.1 [g / m ² · day] on the inorganic thin film layer surface of the transparent moisture-proof film. And having a plastic film through an adhesive layer or pressure-sensitive adhesive layer having a tensile storage elastic modulus at 100 ° C. of 1 × 10 ⁴ [Pa] or more and 5 × 10 ⁵ [Pa] or less and a thickness of 13 μm or more. It has been found that the transparent laminated moisture-proof film, which is characterized, can simultaneously satisfy the suppression of deterioration of moisture resistance and the suppression of deterioration of interlayer strength in a high-temperature and high-humidity environment, and has completed the present invention.
Moreover, this invention is a surface protection member for solar cells characterized by having the said transparent laminated moisture-proof film.

According to the present invention, a moisture-proof film having an inorganic thin film layer on one surface of a substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day], the inorganic thin film layer surface of the moisture-proof film, and an adhesive or adhesive With regard to the durability of transparent laminated moisture-proof film having a plastic film to be bonded via an agent, a transparent laminated moisture-proof film with excellent moisture resistance and moisture resistance that does not deteriorate the moisture resistance and interlayer strength over the long term has been realized. It is possible to provide a highly moisture-proof solar cell surface protective material that is effective in preventing performance degradation at the same time and improving the durability of the solar cell.

Hereinafter, the present invention will be described in more detail.
Usually, a transparent laminated moisture-proof film is applied to a plastic film such as a weather resistant film by diluting an adhesive layer or pressure-sensitive adhesive layer diluted with a solvent to a predetermined thickness, and the solvent is evaporated by drying in the range of 70 ° C to 140 ° C. After forming the adhesive layer or the pressure-sensitive adhesive layer on the plastic film, the inorganic thin film surface of the moisture-proof film is bonded to the adhesive or the pressure-sensitive adhesive side. Furthermore, when the transparent laminated moisture-proof film is used as a surface protective material for a device such as a solar cell, an adhesive layer or a pressure-sensitive adhesive layer diluted with a solvent in the same manner as described above on the back surface of the moisture-proof film if necessary. After the solvent is evaporated by drying in the range of 70 ° C to 140 ° C to form an adhesive layer or a pressure-sensitive adhesive layer on the moisture-proof film, another film is pasted and cured at a predetermined temperature. Create a surface protector. Curing is performed in the range of 30 ° C to 80 ° C for 1 day to 1 week. In this lamination process, heat and bonding tension act on each film, and residual strain accumulates in the transparent laminated moisture-proof film. The prepared surface protective material is heated and melted by vacuum lamination together with the solar cell element and the sealing material, and is integrated into the solar cell. This vacuum lamination process is performed in the range of 130 ° C to 180 ° C.

  Thus, the laminated moisture-proof film is subjected to heat treatment in the range of 130 ° C. to 180 ° C., which is a temperature much higher than the drying and curing temperature of the adhesive in the vacuum lamination process. The residual strain accumulated in the above-described lamination process acts as stress on each lamination interface during storage in a high temperature and high humidity environment. In particular, when residual strain accumulates in a plastic film, the film shrinks due to the temperature in a high-temperature and high-humidity environment, stress acts on the inorganic thin film layer, and serious deterioration of the inorganic thin film layer occurs.

In particular, in the case of a moisture-proof film having a high moisture resistance of less than 0.1 [g / m ² · day], the deterioration of moisture resistance due to shrinkage of the plastic film is significant. This is because a small amount of defects inside the inorganic thin film layer and between the moisture-proof film substrate and the inorganic thin film layer has a significant influence on the high moisture resistance.
As described above, the present inventors reduce the stress acting on the inorganic thin film layer of the moisture-proof film in a high-temperature and high-humidity environment by relaxing the stress from the plastic film in the adhesive layer or the pressure-sensitive adhesive layer. It has been found that both the suppression of inferiority and the interlaminar strength can be realized.

  Specifically, in order to reduce stress transmission due to shrinkage applied to the inorganic thin film layer resulting from residual strain in the plastic film in a high temperature and high humidity environment, an adhesive layer used for bonding in vacuum lamination or It is important that the elastic modulus of the pressure-sensitive adhesive layer is sufficiently low and flexible, and it is important that stress is absorbed by deformation of the adhesive layer or the pressure-sensitive adhesive layer. Adhesion with low elastic modulus in a high-temperature environment such as lamination It is important to use an agent layer or an adhesive layer.

Hereinafter, the present invention will be described in detail.
The transparent laminated moisture-proof film in the present invention includes a transparent moisture-proof film having an inorganic thin film layer on at least one surface of the substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day], and an inorganic material of the transparent moisture-proof film. A plastic film is placed on the surface of the thin film layer through an adhesive layer or pressure-sensitive adhesive layer having a tensile storage elastic modulus at 100 ° C. of 1 × 10 ⁴ [Pa] or more and 5 × 10 ⁵ [Pa] or less and a thickness of 13 μm or more. It is characterized by having.

<Transparent laminated moisture-proof film>
[Transparent moisture-proof film]
In the present invention, the transparent moisture-proof film has an inorganic thin film layer on at least one surface of the substrate, and its water vapor transmission rate is less than 0.1 [g / m ² · day].
(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, polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are particularly preferable from the viewpoints of surface smoothness, film strength, heat resistance, and the like.

  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, the 150 ° C. heat shrinkage ratio is preferably 0.01 to 5%, more preferably 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. Also contains silane coupling agents, titanium coupling agents, light blocking agents, ultraviolet absorbers, stabilizers, lubricants, antiblocking agents, antioxidants, etc., or they are copolymerized with the above resins Things can be used.

  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 transparent laminated moisture-proof film, a coating film of a metal such as aluminum is known. However, when applied to an electronic device such as a solar cell, there is no fear of current leakage and the transparency. From the viewpoint of superiority, an inorganic oxide coating film such as silica or 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 inorganic thin film layer 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 expression. 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 handleability, and 12-25 micrometers is still more preferable.

(Transparent moisture-proof film)
In the present invention, the transparent moisture-proof film has the inorganic thin film layer on at least one surface of the substrate, and its water vapor transmission rate is less than 0.1 [g / m ² · day].
The present invention relates to a transparent laminated moisture-proof film that is preferably used for devices such as solar cells and other electronic devices that are desired to maintain high moisture resistance for a long period of time. Need to be. Accordingly, in the present invention, the transparent moistureproof film is less than the water vapor transmission rate of 0.1 [g / m ² day], preferably 0.05 [g / m ² · day or less, more preferably, 0.03 [g / m ² · day] or less.

[Plastic film]
The plastic film laminated to the transparent laminated film transmits stress to the adhesive layer, pressure-sensitive adhesive layer or inorganic thin film layer due to its small shrinkage even in temperature and humidity changes under high temperature and high humidity environment such as vacuum lamination. It is preferable that the shrinkage rate is small, for example, a low-shrinkage weathering base material such as polyethylene naphthalate, and in the case of a polyethylene terephthalate film or a fluorine-based film having a large shrinkage rate, Reduction in shrinkage and the like can be achieved by heat treatment.

  Specifically, the plastic film is preferably a film containing an ultraviolet absorber in a polyester resin, acrylic resin or polycarbonate resin, or a fluororesin film. For example, polytetrafluoroethylene (PTFE), 4-fluoride film is preferable. Ethylene-perchloroalkoxy copolymer (PFA), 4-fluoroethylene-6-fluoropropylene copolymer (FEP), 2-ethylene-4-fluoroethylene copolymer (ETFE), poly-3- Fluorine resin films such as fluorinated ethylene chloride (PCTFE), polyvinylidene fluoride (PVDF), and polyvinyl fluoride (PVF), or ultraviolet light on resins such as acrylic, polycarbonate, polyethylene terephthalate (PET), and polyethylene naphthalate (PEN) Kneading the absorbent It is preferably used for depositing the resin composition, but is not limited thereto.

From the viewpoint of long-term durability, as the resin forming the plastic film, 2-ethylene-4-fluoroethylene copolymer (ETFE), 4-fluoroethylene-6-fluoropropylene copolymer (FEP), Polyvinylidene fluoride (PVDF) is more preferably used.
From the viewpoint of long-term weather resistance and film shrinkage, a resin composition obtained by coating and kneading an ultraviolet absorber with a resin such as polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) 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.

The plastic film is preferably a weather-resistant film that is highly flexible and has excellent heat resistance, moisture resistance, and UV durability when considered for use in solar cell protective materials. A conductive polyester film is preferably used.
The thickness of the plastic 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.

  Examples of the ultraviolet absorber include various types such as benzophenone-based, benzotriazole-based, triazine-based, salicylic acid ester-based, 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. Door can be.

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 the salicylic acid ester group include phenyl salicylate and p-octylphenyl salicylate.
The addition amount of the ultraviolet absorber is usually about 0.01 to 2.0% by mass, preferably 0.05 to 0.5% by mass in the plastic film.

  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.

  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. The addition amount of the hindered amine light stabilizer is usually about 0.01 to 0.5% by mass in the plastic film, and preferably 0.05 to 0.3% by mass.

[Adhesive layer or adhesive layer]
The transparent laminated moisture-proof film of the present invention bonds the inorganic thin film layer surface of the moisture-proof film and the plastic film via an adhesive or a pressure-sensitive adhesive.
In the present invention, the adhesive layer or the pressure-sensitive adhesive layer has a tensile storage elastic modulus of 1 × 10 ⁴ [Pa] or more and 5 × 10 ⁵ [Pa] or less at 100 ° C., a frequency of 10 Hz, and a strain of 0.1%. The thickness is 13 μm or more. That is, when the tensile storage elastic modulus at 100 ° C. is 1 × 10 ⁴ [Pa] or more, the pressure-sensitive adhesive layer or the adhesive layer does not flow during heating such as vacuum lamination, and the layer thickness can be kept uniform. Yes, if it is 5 × 10 ⁵ [Pa] or less, the adhesive layer or the pressure-sensitive adhesive layer absorbs the stress generated by the shrinkage of the opposing film via the adhesive layer or the pressure-sensitive adhesive layer. It is possible to prevent damage to the thin film layer, which is preferable. From the above viewpoint, the tensile storage elastic modulus at 100 ° C. of the adhesive layer or the pressure-sensitive adhesive layer is 1 × 10 ⁴ [Pa] or more and 5 × 10 ⁵ [Pa] or less, and 1 × 10 ⁵ [Pa]] to It is preferably 5 × 10 ⁵ [Pa].

In the present invention, the adhesive or pressure-sensitive adhesive used in the above-mentioned adhesive layer or pressure-sensitive adhesive layer has a tensile storage modulus at 100 ° C. of 5 × 10 ⁵ [Pa] or less and an adhesive strength at room temperature (20 ° C.). From the viewpoint of exhibiting a tensile storage elastic modulus of 1 × 10 ⁶ [Pa] or more in order to maintain the viscosity, those containing an acrylic pressure-sensitive adhesive are preferred, and those containing an acrylic pressure-sensitive adhesive as the main component are more preferred. Here, the main component is a purpose that allows other components to be included within a range that does not hinder the effects of the present invention, and does not limit the specific content, but is generally an adhesive layer or an adhesive. When the total component of the agent layer is 100 parts by mass, it is 50 parts by mass or more, preferably 65 parts by mass or more, more preferably 80 parts by mass or more and occupies a range of 100 parts by mass or less.

Examples of the acrylic pressure-sensitive adhesive include a main monomer component having a low glass transition point (Tg) that imparts tackiness, a comonomer component having a high Tg that imparts adhesiveness and cohesive force, and a functional group-containing monomer for improving crosslinking and adhesion. A polymer or copolymer (hereinafter referred to as “acrylic (co) polymer”) mainly composed of components is preferred.
Examples of the main monomer component of the acrylic pressure-sensitive adhesive include alkyl acrylates such as ethyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, cyclohexyl acrylate, and benzyl acrylate. And alkyl methacrylates such as butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, and benzyl methacrylate. These may be used alone or in combination of two or more.

Examples of the comonomer component of the acrylic pressure-sensitive adhesive include methyl acrylate, methyl methacrylate, ethyl methacrylate, vinyl acetate, styrene, acrylonitrile and the like. These may be used alone or in combination of two or more.
Examples of the functional group-containing monomer component of the acrylic pressure-sensitive adhesive include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, 2-hydroxyethyl (meth) acrylate, and 2-hydroxypropyl (meta ) Hydroxyl group-containing monomers such as acrylate and N-methylolacrylamide, acrylamide, methacrylamide, glycidyl methacrylate and the like. These may be used alone or in combination of two or more.

Examples of the initiator used for polymerization of the monomer component of the acrylic pressure-sensitive adhesive include azobisisobutylnitrile, benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, and the like. Moreover, there is no restriction | limiting in particular about the copolymerization form of the acrylic (co) polymer used as the main component of the said acrylic adhesive, Any of a random, a block, and a graft copolymer may be sufficient.
Moreover, as a molecular weight in case the said acrylic adhesive is the above-mentioned acrylic type (co) polymer, what is 300,000-1,500,000 is preferable at a mass mean molecular weight, and it is further that it is 400,000-1 million preferable. By adjusting the mass average molecular weight within the above range, adhesion to the adherend and adhesion durability can be secured, and floating and peeling can be suppressed.

Further, in the acrylic (co) polymer, the content of the functional group-containing monomer component unit is preferably in the range of 1 to 25% by mass. By making this content within the above range, the adhesiveness and the degree of crosslinking with the adherend are ensured, and the tensile storage elastic modulus of the pressure-sensitive adhesive layer, which is an essential condition in the present invention, is 5.0 × at 100 ° C. The value can be 10 ^{4 to} 5.0 × 10 ⁵ Pa.

  The adhesive or pressure-sensitive adhesive in the present invention preferably contains an ultraviolet absorber. As the ultraviolet absorber that can be used, the same ultraviolet absorbers contained in the above-mentioned plastic film can be used.

In the present invention, the adhesive layer or the pressure-sensitive adhesive layer may be formed by directly coating the inorganic thin film layer of the plastic film or the moisture-proof film. In the case of a pressure-sensitive adhesive, the pressure-sensitive adhesive is subjected to a peeling treatment. It can form by apply | coating to the peeling process surface of a peeling sheet, and joining this to the inorganic thin film layer of a plastic film or a moisture-proof film.
The pressure-sensitive adhesive to be coated (hereinafter referred to as coating liquid) includes an organic solvent system, an emulsion system, and a solvent-free system, but an organic solvent system is preferable for applications such as solar cell members that are required to have water resistance. .
Examples of the organic solvent used in the organic solvent-based coating liquid include toluene, xylene, methanol, ethanol, isobutanol, n-butanol, acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran. 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, the pressure-sensitive adhesive layer is usually formed by drying at a temperature of 70 to 110 ° C. for about 1 to 5 minutes.
The thickness of the adhesive layer or the pressure-sensitive adhesive layer needs to be 13 μm or more, preferably 15 μm or more, more preferably 20 μm or more, from the viewpoint of obtaining a sufficient adhesive force. Further, from the viewpoint of providing a coatable thickness, the thickness is preferably 100 μm or less, and more preferably 50 μm or less.

[Transparent laminated moisture-proof film]
For the purpose of further improving physical properties (flexibility, heat resistance, transparency, adhesiveness, etc.), molding processability, economic efficiency, etc., within the range not departing from the gist of the present invention, in the transparent laminated moisture-proof film of the present invention. For example, polyolefin-based resins and various elastomers (olefin-based, styrene-based, 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 the like It can contain 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 a hydrogenated derivative of an alicyclic petroleum resin having a softening temperature of 100 to 150 ° C, preferably 120 to 140 ° C is particularly preferable. Usually, in each film which comprises a transparent lamination moisture-proof film, 20 mass% or less is preferable, and 10 mass% or less is still more preferable.

(Additive)
Moreover, a various additive can be added to a transparent laminated moisture-proof film as needed. Examples of the additive include a silane coupling agent, an antioxidant, a weather resistance stabilizer, a light diffusing agent, a nucleating agent, a pigment (for example, a white pigment), a flame retardant, and a discoloration preventing agent. 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 weathering stabilizer is added for reasons described later. 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 transparent laminated moisture-proof film. 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 commercial products can be applied, 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, triphenol (vitamin E) and the like can be mentioned.
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 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 film constituting the transparent laminated moisture-proof film.

(Film forming method)
As a method for forming each film excluding the adhesive layer or the pressure-sensitive adhesive layer constituting the transparent laminated moisture-proof film used in the present invention, a known method such as a single-screw extruder, a multi-screw extruder, a Banbury mixer, a kneader, etc. Although there is no particular limitation, an extrusion casting method using a T die, a calendar method, or the like can be adopted. An extrusion casting method using a die 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 weathering stabilizers may be dry blended with the resin in advance and then supplied to the hopper. The master batch may be supplied after being prepared, or a master batch in which only the additive is previously concentrated in the resin may be prepared and supplied.

  The transparent laminated moisture-proof film of the present invention is obtained by applying the adhesive or pressure-sensitive adhesive to each film formed as described above, and drying the adhesive or pressure-sensitive adhesive at a temperature of 70 to 140 ° C., for example, and 0 to 80 ° C. It can be manufactured by bonding at a temperature of. From the viewpoint of sufficiently bringing the adhesive layer or the pressure-sensitive adhesive layer to the degree of saturation crosslinking, the obtained laminate is preferably cured at a temperature of 30 to 80 ° C. for 1 to 7 days.

  The transparent laminated moisture-proof film of the present invention is excellent in flexibility and moisture-proof properties in which moisture resistance and interlayer strength are not deteriorated even after heat treatment under a high heat environment, that is, heat lamination conditions.

  Although the thickness of a transparent laminated moisture-proof film is not specifically limited, Usually, it is about 30-100 micrometers, Preferably it is about 40-80 micrometers, More preferably, it is used in the sheet form of about 40-70 micrometers.

(Dampproofness of transparent laminated moistureproof film)
As described above, the transparent laminated moisture-proof film of the present invention is moisture-proof before heat treatment by using a transparent moisture-proof film having an inorganic thin film layer on the substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day]. The initial moisture proof property is preferably 0.1 [g / m ² · day] or less, more preferably 0.05 [g / m ² · day] or less in terms of water vapor transmission rate. it can.
Since the transparent laminated moisture-proof film of the present invention can be used as a surface protective material for electronic devices that require excellent moisture-proof properties, it is excellent in initial moisture-proof properties and in a high-temperature and high-humidity environment. It is preferable that it is a transparent laminated moisture-proof film which is also excellent in moisture resistance during storage.

Further, by using the adhesive or pressure-sensitive adhesive, the moisture resistance is deteriorated due to vacuum lamination and a continuous high-temperature and high-humidity environment by a pressure coker test (120 ° C., 32 hours) according to JIS C 60068-2-66. The degree, that is, (the water vapor transmission rate after the high-temperature and high-humidity environment / initial water vapor transmission rate) can be preferably 25 or less, more preferably 15 or less.
The “initial moisture resistance” of the transparent laminated moisture-proof film in the present invention refers to moisture resistance before the member receives a history of heat, etc. in a high temperature and high humidity environment such as a vacuum lameet condition, and moisture resistance due to heat or the like. It means the value before deterioration occurs. Therefore, it includes changes over time from immediately after manufacture to before high-temperature and high-humidity treatment. For example, it means a moisture resistance value in a state where a heat treatment such as a high temperature and high humidity environment around 100 ° C. and a thermal lamination treatment performed at 130 to 180 ° C. for 10 to 40 minutes is not performed. The same applies to the “initial water vapor transmission rate”. The meaning of “initial” is the same for “initial peel force”.

When the transparent laminated moisture-proof film is exposed to high temperature and high humidity, the adhesive layer or the pressure-sensitive adhesive layer is in contact with the inorganic thin film layer side of the moisture-proof film. This is because it greatly affects the degree of deterioration.
As a cause of the moisture-proof deterioration of the transparent laminated moisture-proof film, the moisture-proof deterioration of the adhesive or the pressure-sensitive adhesive itself can be mentioned. In this regard, it is effective to select an adhesive layer or a pressure-sensitive adhesive layer coating that is difficult to hydrolyze. Another cause is deterioration of moisture resistance due to damage to the vapor deposition surface of the inorganic thin film layer film.

  The inventors of the present invention designed the adhesive layer or the pressure-sensitive adhesive layer by paying attention to not deteriorating the surface of the inorganic thin film layer under high temperature and high humidity, and obtained the transparent laminated moisture-proof film of the present invention. Degradation of the inorganic thin film layer surface, when the inorganic thin film and the adhesive layer or pressure-sensitive adhesive layer form a strong chemical bond, the adhesive layer or pressure-sensitive adhesive layer changes in viscoelasticity or the adhesive layer or pressure-sensitive adhesive layer coating, This is considered to be due to the fact that a large stress is applied to the inorganic thin film layer due to the shrinkage. On the other hand, when the adhesion between the inorganic thin film and the adhesive layer or the pressure-sensitive adhesive layer is weak, the stress due to the change in physical properties of the adhesive or the pressure-sensitive adhesive coating film is reduced, so that deterioration of moisture resistance is prevented. The reason why the inorganic thin film and the adhesive layer or pressure-sensitive adhesive layer form a chemical bond is thought to be due to, for example, a reaction between a defective portion of the SiOx layer and a hydroxyl group in the adhesive layer or pressure-sensitive adhesive layer, but this is suppressed. In order to do this, the number of reactive functional groups in the adhesive or pressure-sensitive adhesive may be reduced. First, the number of unreacted functional groups after application or curing of the adhesive or pressure-sensitive adhesive may be mentioned.

Furthermore, as for the physical properties of the adhesive layer or the pressure-sensitive adhesive layer, it is desirable that they have a certain degree of softness and thickness and are brought into close contact with van der Waals force from the viewpoint of protecting the inorganic thin film layer and preventing deterioration of moisture resistance. That is, a pressure-sensitive adhesive or an adhesive having properties as a pressure-sensitive adhesive is effectively used. If the adhesive or pressure-sensitive adhesive coating is too hard, it tends to be subjected to stress between the films due to shrinkage and the like, and the inorganic thin film layer is likely to deteriorate. Therefore, the tensile storage elastic modulus at 100 ° C. is 1 × 10 ⁴ [Pa] or more. It is 5 × 10 ⁵ [Pa] or less, and the thickness of the adhesive layer or the pressure-sensitive adhesive layer is 13 μm or more.
Thus, by satisfy | filling the said moisture proofness, inferiority of a power generation element and the rusting of an internal conducting wire and an electrode can be prevented.
Each moisture-proof property in the present invention can be evaluated according to various conditions of JIS Z0222 “moisture-proof packaging container moisture permeability test method” and JIS Z0208 “moisture-proof packaging material moisture permeability test method (cup method)”.

(Interlayer strength of transparent laminated moisture-proof film)
The transparent laminated moisture-proof film of the present invention is obtained by using the adhesive or pressure-sensitive adhesive after vacuum lamination and a pressure coker test (120 ° C., 32 hours) according to JIS C 60068-2-66. Interlayer strength of 5 N / 15 mm or more can be achieved.
There are various methods for maintaining the interlayer strength after the pressure cooker test in addition to considering the above-mentioned adhesive layer or pressure-sensitive adhesive layer selection conditions, for example, at 100 ° C. of the adhesive layer or pressure-sensitive adhesive layer coating film. If the tensile storage modulus of the adhesive layer is too low, the adhesive layer or the pressure-sensitive adhesive layer flows and the interlayer strength cannot be maintained. Therefore, the tensile storage elastic modulus at 100 ° C. of the adhesive layer or the pressure-sensitive adhesive layer is defined as the above range. It is conceivable to set the above value by doing so.

  Further, when the molecular weight of the adhesive layer or the pressure-sensitive adhesive layer is reduced by hydrolysis under high temperature and high humidity, the cohesive force is lowered and the interlayer strength is lowered. Even when hydrolysis occurs, the carboxylic acid and hydroxyl group generated by hydrolysis may interact with the inorganic thin film layer to generate a new bond. In this case, the interlayer strength is maintained or increased. However, a bond partially generated under high temperature and high humidity is likely to be subjected to stress due to shrinkage, and there is a tendency that uniform adhesion cannot be obtained.

In addition, when the adhesive force to the inorganic thin film layer of the adhesive layer or the pressure-sensitive adhesive layer in the present invention is low from the beginning of the production of the transparent laminated moisture-proof film or when the adhesive force decreases during vacuum lamination, the adhesive layer or Stress propagation from the pressure-sensitive adhesive layer to the inorganic thin film layer is relaxed, and deterioration of moisture resistance is suppressed. However, the fact that the interlayer strength does not satisfy the specific value mentioned above may cause delamination of the transparent laminated moisture-proof film when used for a solar cell module or the like. The strength is a value after continuous high heat treatment by a pressure coker test (120 ° C., 32 hours) according to JIS C 60068-2-66 which is a vacuum lamination and acceleration test, preferably 5 N / 15 mm or more. Preferably it is 7N / 15mm or more.
The interlayer strength can be measured using a tensile tester after cutting the laminated film into a predetermined strip shape as described later.

(Use of transparent laminated moisture-proof film and surface protection member)
The transparent laminated moisture-proof film of the present invention is used for a protective member for solar cells and a surface protective member for electronic paper that require long-term durability, particularly a solar cell of a compound-based power generation element solar cell module or a flexible solar cell module. It is preferable to be used for a surface protection member for the purpose of preventing deterioration of the power generation element due to moisture or water permeation, preventing rusting of internal conductors and electrodes, and achieving retention of electromotive force over a long period of time.

The transparent laminated moisture-proof film for solar cells is composed of the transparent laminated moisture-proof film, in particular, by bonding the specific plastic film to the inorganic thin film layer via the specific adhesive layer or pressure-sensitive adhesive layer, under high temperature conditions. In addition, it realizes a transparent laminated moisture-proof film excellent in flexibility and moisture-proof properties that does not degrade moisture resistance and interlayer strength over a long period of time, and simultaneously prevents performance degradation of solar cells, etc., and improves durability of solar cells etc. It is possible to provide a surface protective material for highly moisture-proof solar cells and electronic paper that are effective for the above-mentioned.
The solar cell surface protective material may be a sealing material / surface protective material integrated type formed by laminating a sealing material. By further laminating the sealing material in advance, it is possible to reduce the work of individually laminating the back surface protection sheet, the sealing material, the power generation element, the sealing material, and the front surface protection sheet in the vacuum lamination process, and the efficiency of manufacturing the solar cell module Can be achieved.

<Solar cell module, solar cell manufacturing method>
The transparent laminated moisture-proof film can be used as a solar cell surface protection member as it is or by being bonded to 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 transparent laminated moisture-proof film of this invention.

  A solar cell module can be produced by using the transparent laminated moisture-proof film of the present invention for the layer structure of a surface protection member such as a front sheet or a back sheet for a solar cell 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 transparent laminated moisture-proof film 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 lower protective material, specifically, an upper protective material (transparent laminated moisture-proof film of the present invention) / sealing material (sealing resin layer) / solar cell element / sealing. Sealing material (sealing resin layer) / lower protective material, sealing material and upper protective material (transparent laminated moisture-proof film of the present invention) on a 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 (transparent laminated moisture-proof film of the present invention), such as sputtering of an amorphous solar cell element on a fluororesin-based transparent protective material, etc. Made with Mention may be made such a configuration as to form a sealing material and a lower protective material on top of. It is optional to attach a glass plate to the outside of the transparent laminated moisture-proof film of the present invention as the upper protective material. In addition, when using the above-mentioned sealing material / surface protective material integrated surface protective material, the above-mentioned sealing material may not be used.

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.
When a solar cell module is formed using the surface protective material in the present invention, the moisture resistance is less than about 1.0 [g / (m ² · day)] in terms of water vapor transmission rate depending on the type of the solar cell power generation element. From a low moisture-proof film to a high moisture-proof film of less than about 0.01 [g / (m ² · day)] is selected as appropriate according to the type of the device, and laminated using a weather-resistant film and the like and an adhesive or a pressure-sensitive adhesive. Form.

  Although it does not specifically limit about each member which comprises the solar cell module produced using the transparent laminated moisture-proof film of this invention, As an sealing material, an ethylene-vinyl acetate copolymer is mentioned, for example. be able to. 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.

  The upper protective material (transparent laminated moisture-proof film of the present invention) / sealing material / solar cell element / sealing material / lower protective material described above for the solar cell module produced using the transparent laminated moisture-proof film of the present invention An example of a simple configuration will be described. In order from the sunlight receiving side, the transparent laminated moisture-proof film, sealing resin layer, solar cell element, sealing resin layer, and back sheet of the present invention are laminated, and a junction box (solar cell element) is further formed on the lower surface of the back sheet. A terminal box for connecting wiring for taking out the electricity generated from 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 transparent laminated moisture-proof film, sealing resin layer, solar cell element, sealing of the present invention It has the process of laminating | stacking a resin layer and a lower protective material in order, and the process of vacuum-sucking them and carrying out thermocompression bonding. Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.

  The solar cell module manufactured using the transparent laminated moisture-proof film 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, depending on the type and module shape of the applied solar cell. It can be applied to various uses regardless of whether it is indoors or outdoors. In particular, among electronic devices, in the use for solar cell protective materials of flexible solar cell modules such as compound-based power generation element solar cell modules and amorphous silicon-based, electronic paper, etc., because high moisture resistance is required, A laminated moisture-proof film considering this continuous high heat treatment is effectively used. Therefore, the solar cell module produced using the transparent laminated moistureproof film of the present invention is particularly preferably used as a surface protective material for the electronic device.

  The solar cell module and / or the solar cell is a solar cell protection sheet, sealing material, power generation element, sealing material, and back surface protection sheet, according to a conventional method, with a vacuum laminator, and preferably at a temperature of 130 to 180 ° C. More preferably 130-150 ° C., degassing time 2-15 minutes, press pressure 0.5-1 atm, press time preferably 8-45 minutes, more preferably 10-40 minutes. Can be manufactured more easily.

  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.

(Physical property measurement)
(1) Adhesive layer or pressure-sensitive adhesive layer tensile storage modulus The adhesive or pressure-sensitive adhesive used on the silicone release PET film is applied to a thickness of 25 g / m ² and cured at 40 ° C. for 4 days. Furthermore, it hold | maintained at 150 degreeC for 30 minutes after that, and formed the adhesive bond layer or the adhesive layer. Thereafter, only the adhesive layer or the pressure-sensitive adhesive layer is taken out and stacked with a predetermined thickness. Using a viscoelasticity measuring device manufactured by IT Measurement Co., Ltd., a trade name “Viscoelasticity Spectrometer DVA-200”, a sample (4 mm in length) , 60 mm in width, 200 μm in thickness) with a vibration frequency of 10 Hz, a strain of 0.1%, a heating rate of 3 ° C./min, and a gap between chucks of 25 mm, the stress against the strain applied to the sample from −100 ° C. to 180 ° C. The tensile storage elastic modulus (MPa) at 100 ° C. was determined from the measured data. In addition, the tensile storage elastic modulus was set to 0 when the measurement at 100 degreeC was difficult from the sample shape change at the time of temperature rising.

(2) Pressure cooker test The transparent laminated moisture-proof film (D-1 to D-4) after pasting and curing each component film is heat-treated at 150 ° C for 30 minutes, and pressure produced by Tommy Seiko Co., Ltd. The cooker test LSK-500 was used, and the test was performed under the test conditions of 120 ° C., 100% humidity and 32 hours.

(3) Moisture-proof property The moisture-proof property of the moisture-proof film (B-1, B-2) was measured by the following method as the water vapor transmission rate after the moisture-proof film was created and stored at 40 ° C for one week.
Moreover, about a transparent laminated moisture-proof film (D-1 to D-4), each measured film is bonded and the measured value after curing is made initial moisture-proof, and after the curing, glass, sealing material, transparent lamination The moisture-proof film, the back side of the moisture-proof film is the sealing material side), heat-treated at 150 ° C. for 30 minutes, and the pressure cooker test, the measured value of each transparent laminated moisture-proof film is the pressure cooker test It was set as the value of the moisture proof later.
Specifically, in accordance with JIS Z 0222 “moisture-proof packaging container moisture permeability test method” and JIS Z 0208 “moisture-proof packaging material moisture permeability test method (cup method)”, the following methods were used for evaluation.
Using two sheets of each moisture-proof film laminate having a moisture permeable area of 10.0 cm × 10.0 cm square, a bag was prepared in which about 20 g of anhydrous calcium chloride was put as a hygroscopic agent and the four sides were sealed. In a constant temperature / humidity apparatus of 72% and measure the mass until about 200 days at intervals of 72 hours or more. From the slope of the regression line between the elapsed time after the fourth day and the bag weight, the water vapor transmission rate (g / m ² · Day). The degree of deterioration of moisture resistance was calculated by [water vapor permeability after pressure cooker test (PC32) / initial water vapor permeability].

(4) Interlaminar strength The initial peel strength of the transparent laminated moisture-proof film and the cured transparent laminated moisture-proof film are heat-treated at 150 ° C for 30 minutes, and the peel strength of the transparent laminated moisture-proof film after the pressure cooker test is measured. The laminate was cut into 15 mm strips, and the interlayer laminate strength (N / 15 mm) was measured at 300 mm / min using a STA-1150 manufactured by ORIENTIC.

(Structure film)
<Plastic film>
A-1: Polyvinylidene fluoride (PVDF) film Kynar 302-PGM-TR (thickness: 30 μm) manufactured by Arkema was used.

<Dampproof film>
Moisture-proof film B-1
A 12 μm thick biaxially stretched polyethylene naphthalate film (manufactured by Teijin DuPont, “Q51C12”) was used as the base film, and the following coating solution was applied to the corona-treated surface and dried to 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 (x = 1.5) having a thickness of 50 nm was formed on the coating layer. ) A moisture-proof film B-1 having a thin film was obtained. The moisture-proof film B-1 produced had a moisture-proof property of 0.01 [g / m ² · day].

Coating solution “GOHSENOL” (degree of saponification: 97.0 to 98.8 mol%, degree of polymerization: 2400) manufactured by Nippon Gosei Co., Ltd. was added to 2810 g of ion-exchanged water and dissolved in an aqueous solution. 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.
In addition, an isocyanate resin (“Sumijour N-3200” manufactured by Sumitomo Bayer Urethane Co., Ltd.) was used as a cross-linking agent, and mixing was performed so that the equivalent ratio of isocyanate groups to hydroxyl groups was 1: 2.

<Dampproof film B-2>
A tech barrier LX made by Mitsubishi Plastics in which silica was vapor-deposited on a 12 μm polyethylene terephthalate resin film was used. Further, the moisture resistance measured by the above method was 0.2 [g / (m ² · day)].

Example 1
Sanae Kaken Co., Ltd. acrylic adhesive tape SANCUARY DK125 (tensile storage elastic modulus 3 × 10 ⁵ Pa, thickness 25 μm) is used to paste the inorganic thin film layers of plastic film A-1 and moisture-proof film B-1 and transparent with a thickness of 67 μm A laminated moisture-proof film D-1 was prepared. Laminated so that glass, sealing material, transparent laminated moisture-proof film D-1 (sealing material side is moisture-proof film (B-1)) and vacuum laminated under conditions of 150 ° C. × 15 minutes, then pressure cooker test The interlaminar strength and moisture resistance were measured. The results are shown in Table 1 together with the tensile storage modulus at 100 ° C.

Comparative Example 1
The main component HD1013 and the same curing agent H62 manufactured by Rock Paint Co., Ltd. are used as the polyurethane adhesive, mixed to a weight ratio of 10: 1, and diluted with ethyl acetate to a solid content concentration of 30%. An adhesive coating solution was prepared.
The adhesive coating solution is applied to the plastic film A-1 and dried to a solid content of 13 g / m ² to form an adhesive layer having a thickness of 13 μm, and the inorganic thin film layer of the moisture-proof film B-1 is applied to the adhesive surface. Bonded towards.
The film was cured at 40 ° C. for 5 days to prepare a transparent laminated moisture-proof film D-2 having a thickness of 55 μm. Glass, sealing material, transparent laminated moisture-proof film D-2 (sealing material side is D-2 moisture-proof film (B-1)) are laminated in this order, and vacuum lamination is performed at 150 ° C. for 15 minutes, Thereafter, a pressure cooker test was carried out to measure interlayer strength and moisture resistance. The results are shown in Table 1 together with the tensile storage modulus at 100 ° C.

Comparative Example 2
Acrylic adhesive tape SANNCARY OP512 (tensile storage elastic modulus 3 × 10 ⁵ Pa, thickness 12 μm) manufactured by Sanei Kaken Co., Ltd. was used in the same manner as in Example 1, and the inorganic thin film layers of weather resistant film A-1 and moisture-proof film B-1 The transparent laminated moisture-proof film D-3 of 54 micrometers in thickness was bonded together. Glass, sealing material, transparent laminated moisture-proof film D-3 (sealing material side is D-3 moisture-proof film (B-1)) are laminated in this order, and vacuum lamination is performed at 150 ° C. for 15 minutes, Thereafter, a pressure cooker test was carried out to measure interlayer strength and moisture resistance. The results are shown in Table 1 together with the tensile storage modulus at 100 ° C.

Comparative Example 3
A transparent laminated moisture-proof film D-4 having a thickness of 67 μm was prepared in the same manner as in Comparative Example 1 except that the moisture-proof film B-1 of Example 1 was changed to B-2, and after vacuum lamination, a pressure cooker test was conducted. Strength and moisture resistance were measured. The results are shown in Table 1 together with the tensile storage modulus at 100 ° C.

Thus, the transparent laminated moisture-proof film of Example 1 which is a laminated body including a transparent moisture-proof film having high moisture-proof properties and an adhesive having a tensile storage modulus value in a specific range is manufactured through a vacuum lamination process. From the evaluation by the pressure cooker test, it was revealed that both the long-term interlayer strength and moisture resistance were maintained.
On the other hand, in Comparative Example 1 using a polyurethane adhesive whose tensile storage elastic modulus exceeded the specified range, the moisture resistance after the pressure cooker test was remarkably reduced, whereas in Comparative Example 2 where the pressure-sensitive adhesive layer was thin It is clear that the interlaminar strength is low from the beginning and further decreases after the pressure cooker test, and any transparent laminated moisture-proof film lacks long-term moisture resistance or interlayer strength compared to Example 1 above. It shows that Further, in Comparative Example 3, the moisture-proof property of the transparent moisture-proof film constituting the transparent laminated moisture-proof film is as low as 0.2 [g / (m ² · day)] from the beginning, and is further lowered after the pressure cooker test. It became clear that the moisture-proof property was insufficient both in the initial stage and in the long term as compared with Example 1 described above.

Claims (9)

A transparent moisture-proof film having an inorganic thin film layer on at least one surface of the substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day], and an inorganic thin film layer surface of the transparent moisture-proof film at 100 ° C. It has a tensile storage elastic modulus of 1 × 10 ⁴ [Pa] or more and 5 × 10 ⁵ [Pa] or less, and has a plastic film through an adhesive layer or pressure-sensitive adhesive layer having a thickness of 13 μm or more. Transparent laminated moisture-proof film.   The transparent laminated moisture-proof film according to claim 1, wherein the adhesive layer or the pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive as a main component.   The transparent laminated moisture-proof film according to claim 1 or 2, wherein the plastic film is a weather-resistant film.   The transparent laminated moisture-proof film according to claim 3, wherein the weather-resistant film is a film containing a resin selected from a polyester resin, an acrylic resin, and a polycarbonate resin and an ultraviolet absorber, or a fluororesin film.   The transparent laminated moisture-proof film according to any one of claims 1 to 4, wherein a substrate of the transparent moisture-proof film is a polyethylene naphthalate (PEN) film.   A surface protective member for a solar cell, comprising the transparent laminated moisture-proof film according to claim 1.   The surface protection member for solar cells of Claim 6 used for the surface protection member of a compound power generation element solar cell module or a flexible solar cell module.   A module for solar cell, comprising the transparent laminated moisture-proof film according to claim 1.   A surface protective member for electronic paper, comprising the transparent laminated moisture-proof film according to claim 1.