JP5449312B2 - Protective material for solar cells - Google Patents

Description

  The present invention relates to a protective material used for solar cells and the like, and more particularly, to a protective material for solar cells that can maintain moisture resistance and prevent the occurrence of delamination.

In recent years, solar cells that directly convert sunlight into electric energy have attracted attention and are being developed from the viewpoint of effective use of resources and prevention of environmental pollution. A solar cell has an ethylene-vinyl acetate copolymer, polyethylene, or polypropylene film between a front protective sheet (hereinafter sometimes referred to as a front sheet) and a back protective sheet (hereinafter sometimes referred to as a back sheet) from the light receiving surface side. It is set as the structure which sealed the cell for solar cells with sealing films, such as.
Such a solar cell is usually manufactured by laminating a front protective film, a sealing material, a power generation element, a sealing material, and a back protective film in this order, and bonding and integrating them by heating and melting. As a solar cell protective material that is a front surface protection sheet or a back surface protection sheet of a solar cell, it is required to have excellent durability against ultraviolet rays. In addition, rusting of internal conductors and electrodes due to permeation of moisture and the like is required. In order to prevent this, it is extremely important to have excellent moisture resistance. Furthermore, it is desired to develop an excellent protective material that causes little deterioration in moisture resistance under long-term use or high-temperature conditions.

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. Create a protective material for solar cells by laminating a polyester film and a polypropylene film on the back, evaluate the moisture resistance after a 1000 hour test at 85 ° C and 85% humidity, and make proposals to prevent moisture degradation. Yes.
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 films on both sides to produce solar cell protective materials, evaluated barrier performance and interlayer strength after 1000 hours accelerated test at 85 ° C and 85% humidity, and proposed to prevent deterioration of both properties. ing.
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 environment test by high temperature and pressure, 105 ° C., 92 hours) are evaluated, and the proposal for preventing the 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 protective materials for solar cells such as compound power generation element solar cell modules that require high performance, in severe environments that are replaced by accelerated durability tests such as the pressure cooker test (PCT), long-term It was not possible to sufficiently maintain moisture resistance and prevent delamination at the edge of the protective material.
The solar cell protective material is excellent in moisture resistance and prevention of delamination, and further desired to maintain the moisture resistance and prevention of delamination over a long period of time. When a film having a high moisture-proof property with a rate of less than 0.1 [g / m ² · day] is used, no specific proposal has been made to enable moisture-proof property and prevention of delamination for a long time. It was a fact.

That is, an object of the present invention is to prevent generation of delamination in a long period of time for a protective material for a solar cell including a moisture-proof film having a water vapor permeability of less than 0.1 [g / m ² · day]. To provide a solar cell protective material that is effective in preventing solar cell performance degradation and improving the durability of solar cells. is there.

As a result of repeated studies, the present inventors have an inorganic film on at least one surface of at least the fluororesin film, the pressure-sensitive adhesive layer, and the base material, and have a water vapor transmission rate of 0.1 [g / m ² · The ratio of the maximum width B of the protective material constituent layer other than the fluorine-based resin film to the width (A) of the fluorine-based resin film, which is a solar cell protective material formed by laminating moisture-proof films less than [day] B / A) by using a solar cell protective material characterized by being smaller than 1, it has been found that it is possible to simultaneously satisfy the deterioration of moisture resistance and prevention of delamination after being laminated with a sealing material, The present invention has been completed.

That is, the present invention
(1) At least a fluorine resin film, an adhesive layer, and a moisture-proof film having an inorganic film on at least one surface of the substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day] are laminated. The ratio of the maximum width B (B / A) of the protective material constituting layer other than the fluorine resin film to the width A of the fluorine resin film is smaller than 1 with respect to the width A of the fluorine resin film. Protective material for solar cells,
(2) The solar cell protective material according to (1), wherein the B / A is 0.7 to 0.98,
(3) The solar cell protective material according to (1) or (2), wherein the layer having the maximum width of the protective material constituting layer other than the fluorine-based resin film is a moisture-proof film,
(4) The adhesive layer has a tensile storage elastic modulus of 5.0 × 10 ⁴ to 5.0 × 10 ⁵ Pa at 100 ° C., a frequency of 10 Hz, and a strain of 0.1%, and a thickness of 13 μm or more. The solar cell protective material according to any one of (1) to (3) above,
(5) A film roll in which the solar cell protective member according to any one of (1) to (4) is wound up by 100 m or more, and (6) any one of (1) to (4) above A solar cell module produced using the solar cell protective material described,
Exist.

  According to the present invention, there is no decrease in moisture resistance or occurrence of delamination even when used at high temperature and high humidity over a long period of time, excellent flexibility and moisture resistance, preventing a decrease in the performance of solar cells, and It is possible to provide a protective material for a highly moisture-proof solar cell that is effective for improving the durability of the solar cell. The solar cell protective material of the present invention is excellent in flexibility and moisture resistance, in which moisture resistance and interlaminar strength do not decrease even after heat treatment in a high heat environment, that is, heat lamination conditions.

It is a schematic sectional drawing which shows an example of the module using the solar cell protective material of this invention.

Hereinafter, the present invention will be described in more detail.
The protective material for solar cells can prevent moisture from entering from the exposed surface of the film by being laminated with a moisture-proof film, but it can be used for a long time as an alternative to accelerated testing in a high-temperature, high-humidity environment. , Due to the ingress of moisture from the end face of the protective material for solar cells, the base material of the adhesive and moisture-proof film used for laminating each film gradually deteriorates, causing delamination from the edges and moisture-proof performance. Decrease may occur.
In particular, in the case of a moisture-proof film having a high moisture-proof property of less than 0.1 [g / m ² · day], the influence of the moisture-proof deterioration due to the shrinkage of the film and the entry of moisture from the end is remarkable. This is because slight defects at the inside of the inorganic film of the moisture-proof film and at the interface between the base material and the inorganic film and deterioration due to hydrolysis of the base material have a significant influence on the moisture resistance.

As described above, the present inventors have at least a fluorine resin film, an adhesive layer, and a base material and an inorganic film formed on at least one surface of the protective material for solar cells, and have a water vapor transmission rate. Is a laminate in which moisture-proof films having a thickness of less than 0.1 [g / m ² · day] are laminated, and the width of the protective material constituting layer including moisture-proof films other than the fluorine-based resin films is By making the structure shorter than the width, as shown in FIG. 1, the end face of the pressure-sensitive adhesive layer 2 and the moisture-proof film 3 in which the sealant 4 has a width shorter than the width of the fluororesin film 1 during vacuum lamination. As a result, it has been found that both the prevention of the moisture-proof deterioration and the prevention of the occurrence of delamination from the end portion can be realized by the effect of wrapping around and sealing the end face.

That is, the present invention provides a moisture-proof film having an inorganic film on at least one surface of at least one of a fluororesin film, an adhesive layer, and a substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day]. The ratio (B / A) of the maximum width B of the protective material constituent layer other than the fluorine resin film to the width A of the fluorine resin film is less than 1 The present invention relates to a solar cell protective material.

<Protective material for solar cells>
[Fluorine resin film]
The solar cell protective material of the present invention has hydrolysis resistance and weather resistance, and has a fluororesin film in order to impart long-term durability.
The fluororesin film preferably has weather resistance. Examples of the fluororesin include polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), tetrafluoroethylene / hexa Fluoropropylene copolymer (FEP), tetrafluoroethylene / ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) and the like are preferably used.

From the viewpoint of long-term durability, tetrafluoroethylene / ethylene copolymer (ETFE) and tetrafluoroethylene / hexafluoropropylene copolymer (FEP) are more preferably used as the resin.
The fluorine resin film preferably has a small change in characteristics even during temperature lamination and high temperature / humidity during vacuum lamination, so in the case of a fluorine film with a large shrinkage, low shrinkage due to prior heat treatment. It is preferable to use a film that has been converted to a rate.

  The width A of the fluororesin film and the maximum width of the protective material constituting layer other than the fluororesin film, that is, the width B of the widest layer among the layers constituting the protective material is the same or B is larger than A In some cases, B / A needs to be smaller than 1 because the thickness of the sealing material that wraps around the end face is small and delamination is likely to occur. On the other hand, if the difference between A and B is too large, the sealing material may not sufficiently wrap around to the end, and the uniformity of the thickness of the laminate after vacuum lamination may not be maintained. Therefore, B / A is preferably from 0.7 to 0.98, more preferably from 0.75 to 0.95 in order to prevent delamination more stably, and from 0.8 to 0.8. 92 is more preferred. If B / A is smaller than 1, it is arbitrary how long A is to the left and right with respect to B, but it is preferable to make A / B equally long. In the present invention, the “film width” means the length in the lateral direction with respect to the length direction of the film unwound from the roll when the protective material is provided in a roll, and is provided in a single sheet. The short side of the four sides.

  Various additives can be added to the fluororesin film as necessary. Examples of the additive include, but are not limited to, an ultraviolet absorber, a weather resistance stabilizer, an antioxidant, an antistatic agent, and an antiblocking agent.

  The thickness of the fluororesin film is generally about 20 to 200 μm, preferably 20 to 100 μm, more preferably 20 to 60 μm from the viewpoints of film handling and cost.

[Dampproof film]
In the present invention, the moisture-proof film has at least an inorganic film formed on at least one surface of the substrate and the water vapor transmission rate is less than 0.1 [g / m ² · day]. . Since the protective material for solar cells of the present invention is desired to maintain high moisture resistance for a long period of time, the initial moisture resistance needs to be a certain level or more. Therefore, in the present invention, the moisture-proof film has a water vapor transmission rate of less than 0.1 [g / m ² day], preferably 0.05 [g / m ² · day] or less, more preferably 0 0.03 [g / m ² · day] or less. The moisture-proof film is preferably transparent when the solar cell protective material is used as a front sheet used on the light-receiving surface side.
The thickness of the moisture-proof film is generally about 5 to 300 μm, preferably 5 to 100 μm, more preferably 8 to 50 μm, and still more preferably 10 to 25 μm from the viewpoint of productivity and ease of handling.

(Base material)
As the base material of the moisture-proof film, a resin film is preferable, and any material can be used without particular limitation as long as it is a resin that can be used for an ordinary solar cell material.
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, biodegradable resin, and the like, and among them, a thermoplastic resin is preferable. Furthermore, polyesters, polyamides, and polyolefins are preferable from the viewpoints of film properties and costs, and polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) are particularly preferable from the viewpoints of surface smoothness, film strength, heat resistance, and the like.

  Moreover, the said base material can add a various additive as needed. Examples of the additive include, but are not limited to, an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a weathering stabilizer, an antiblocking agent, and an antioxidant.

Examples of ultraviolet absorbers that can be used 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. In That.

  The benzotriazole ultraviolet absorber is a hydroxyphenyl-substituted benzotriazole compound, for example, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2- (2-hydroxy-5-t-butylphenyl) Benzotriazole, 2- (2-hydroxy-3,5-dimethylphenyl) benzotriazole, 2- (2-methyl-4-hydroxyphenyl) benzotriazole, 2- (2-hydroxy-3-methyl-5-t- Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-amylphenyl) benzotriazole, 2- (2-hydroxy-3,5-di-t-butylphenyl) benzotriazole and the like. be able to.

Examples of triazine ultraviolet absorbers include 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl] -5- (octyloxy) phenol, 2- ( Examples include 4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyloxy) phenol.
Examples of the salicylic acid ester group include phenyl salicylate and p-octylphenyl salicylate.
Content of the ultraviolet absorber in a base material is about 0.01-2.0 mass% normally, Preferably it is 0.05-0.5 mass%.

  In addition to the above UV absorbers, hindered amine light stabilizers can be 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) sebacate, 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 content of the hindered amine light stabilizer in the substrate is usually about 0.01 to 0.5% by mass, preferably 0.05 to 0.3% by 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, 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 in the substrate, and is preferably added to 0.2 to 0.5% by mass.

The resin film as the substrate is formed by using the above raw materials, but may be unstretched or stretched. Furthermore, it may be either a single layer or a multilayer.
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 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 terephthalate film, a biaxially stretched polyethylene naphthalate film, a polyethylene terephthalate and / or a coextruded biaxially stretched film of polyethylene naphthalate and another resin is preferable.

  Moreover, generally the thickness of the said base material is about 5-300 micrometers, Preferably it is 5-100 micrometers, 8-50 micrometers is more preferable from the point of productivity or ease of handling, and 10-25 micrometers is still more preferable.

  In addition, it is preferable to form an anchor coat layer on the base material in order to improve adhesion with the inorganic film. The anchor coat layer contains solvent-based or water-soluble polyester resin, isocyanate resin, urethane resin, acrylic resin, modified vinyl resin, vinyl alcohol resin and other alcoholic hydroxyl group-containing resins, vinyl butyral resin, nitrocellulose resin, oxazoline group-containing Resins, carbodiimide group-containing resins, melamine group-containing resins, epoxy group-containing resins, modified styrene resins, modified silicone resins and the like can be used alone or in combination of two or more. Moreover, a silane coupling agent, a titanium coupling agent, an ultraviolet absorber, a weathering stabilizer, a lubricant, an antiblocking agent, an antioxidant, and the like can be added to the anchor coat layer as necessary. As the ultraviolet absorber, weather stabilizer and antioxidant, the same ones as those used for the aforementioned substrate can be used, and the weather stabilizer and / or ultraviolet absorber is copolymerized with the resin described above. The polymer type can also 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 film. A known coating method is appropriately adopted as the formation method. For example, a reverse roll coater, a gravure coater, a rod coater, an air doctor coater, or 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).

(Inorganic film)
Examples of the inorganic substance constituting the inorganic film include silicon, aluminum, magnesium, zinc, tin, nickel, titanium, hydrogenated carbon, and the like, or oxides, carbides, nitrides, or mixtures thereof. Therefore, silicon oxide, silicon nitride, silicon oxynitride, aluminum oxide, and diamond-like carbon are preferable. In particular, silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxide are preferable because high gas barrier properties can be stably maintained.

  As a method for forming the inorganic film, 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 high gas barrier properties 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).

  The thickness of the inorganic film is preferably 10 to 1000 nm, more preferably 20 to 800 nm, and still more preferably 20 to 600 nm, from the viewpoint of stable moistureproof expression. The inorganic film may be a single layer or a multilayer.

[Adhesive layer]
In the production of a solar cell protective material, for example, when laminating constituent members such as a resin film constituting the solar cell protective material, an adhesive or pressure-sensitive adhesive diluted with a solvent is applied on the resin film or the like. After applying to the thickness and evaporating the solvent by drying usually in the range of 70 ° C to 140 ° C to form an adhesive layer or pressure-sensitive adhesive layer on the resin film or the like, the other resin film or the like is bonded to the adhesive layer or pressure-sensitive adhesive. It repeats pasting toward the layer side, and finally makes it through curing at a predetermined temperature. Curing is performed, for example, in the range of 30 ° C. to 80 ° C. for 1 day to 1 week.

  In such a laminating process, heat and bonding tension act on each resin film and the like, and residual strain is accumulated in the protective material for solar cells. However, the accumulated residual strain is measured in a high-temperature and high-humidity environment. In use and storage, it acts as a stress on each laminated interface. In particular, when residual strain accumulates in the resin film, the resin film contracts in a high temperature and high humidity environment, gives stress to the inorganic film, causes defects in the inorganic film, and causes a decrease in moisture proof performance.

Therefore, in a high-temperature and high-humidity environment, the degree of softness and thickness is reduced to some extent from the viewpoint of reducing the transmission of stress due to resin film shrinkage resulting from residual strain to the inorganic film, protecting the inorganic film and preventing deterioration of moisture resistance. It is preferable to laminate the fluororesin film layer and the moisture-proof film through an adhesive layer that has a close contact with the van der Waals force. Therefore, the pressure-sensitive adhesive layer preferably has a tensile storage elastic modulus of 5.0 × 10 ⁴ to 5.0 × 10 ⁵ Pa at 100 ° C., a frequency of 10 Hz, and a strain of 0.1%. That is, when the tensile storage elastic modulus at 100 ° C. is 5.0 × 10 ⁴ [Pa] or more, the pressure-sensitive adhesive layer does not flow when laminating components such as a resin film constituting the solar cell protective material, It is possible to keep the layer thickness uniform, and if it is 5.0 × 10 ⁵ Pa or less, the pressure-sensitive adhesive layer absorbs stress generated by shrinkage of the opposing film through the pressure-sensitive adhesive layer. This makes it possible to prevent damage to the inorganic film. The tensile storage elastic modulus at 100 ° C., frequency 10 Hz, and strain 0.1% of the pressure-sensitive adhesive layer is preferably 7.0 × 10 ⁴ Pa to 5.0 × 10 ⁵ Pa, and 1.0 × 10 ⁵ Pa. More preferably, it is -5.0 * 10 < ⁵ > Pa.

The pressure-sensitive adhesive layer has a tensile storage elastic modulus of 1.0 × 10 ⁶ 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 room temperature (20 ° C.). Is preferred.
Furthermore, the cause of the deterioration of the moisture resistance of the protective material for solar cells is the deterioration of the moisture resistance of the adhesive itself. For this, it is effective to select an adhesive that is difficult to hydrolyze.

  From the above viewpoint, in the present invention, the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer preferably includes an acrylic pressure-sensitive adhesive, and more preferably includes an acrylic pressure-sensitive adhesive as a main component. Here, the main component is a purpose that allows other components to be included within a range that does not impede the effects of the present invention, and does not limit the specific content, but generally the configuration of the pressure-sensitive adhesive layer When the total component 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 mainly composed of components (hereinafter referred to as “acrylic (co) polymer”) is preferred.
Examples of the main monomer component of the acrylic (co) polymer include acrylic acid esters such as ethyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, and octyl acrylate. These may be used alone or in combination of two or more.

As the comonomer component of the acrylic (co) polymer, methyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, vinyl acetate, styrene, acrylonitrile Etc. These may be used alone or in combination of two or more.
Examples of the functional group-containing monomer component of the acrylic (co) polymer include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy Examples thereof include hydroxyl group-containing monomers such as propyl (meth) acrylate and N-methylolacrylamide, acrylamide, methacrylamide and glycidyl methacrylate. 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 (co) polymer 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 (co) polymer, what is 300,000-1,500,000 in a mass mean molecular weight is preferable, and it is further 400,000-100,000. preferable. By setting the mass average molecular weight within the above range, adhesion to the adherend and adhesion durability can be ensured, 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 adhesion and the degree of crosslinking with the adherend are ensured, and the tensile storage elastic modulus of the pressure-sensitive adhesive layer is 5.0 × 10 ^{4 to} 5.0 × at 100 ° C. The value can be in the range of 10 ⁵ Pa.
When a strong chemical bond is formed between the pressure-sensitive adhesive layer and the inorganic film, a large stress is applied to the inorganic film due to a change in the viscoelasticity of the pressure-sensitive adhesive layer or decomposition or shrinkage of the pressure-sensitive adhesive layer coating film. A factor for forming the bond is considered to be due to a reaction between a defective portion of an inorganic film such as a SiOx layer and a hydroxyl group in the pressure-sensitive adhesive layer. In order to suppress this, the number of reactive functional groups in the pressure-sensitive adhesive may be reduced, and it is preferable to reduce the number of unreacted functional groups after application and curing of the pressure-sensitive adhesive layer.

  The pressure-sensitive adhesive layer in the present invention preferably contains an ultraviolet absorber. As an ultraviolet absorber, the same thing as what is used for the above-mentioned base material can be used.

In the present invention, the pressure-sensitive adhesive layer may be formed by directly applying to a fluororesin film or a moisture-proof film, or the pressure-sensitive adhesive may be applied to a release-treated surface of a release sheet that has been subjected to a release treatment. Can also be formed by bonding to 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 desirable for uses 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 pressure-sensitive adhesive layer is preferably 13 μm or more, more preferably 15 μm or more, still more preferably 18 μm or more, and most preferably 20 μm or more from the viewpoint of obtaining sufficient adhesive strength. Further, from the viewpoint of providing a coatable thickness, the thickness is preferably 100 μm or less, and more preferably 50 μm or less.

The solar cell protective material of the present invention preferably has at least the fluorine-based resin film, the pressure-sensitive adhesive layer, and the moisture-proof film in this order, and when used for a front sheet, has a fluorine-based resin film on the exposed side. It is preferable.
The solar cell protective material of the present invention is intended to further improve physical properties (flexibility, heat resistance, transparency, adhesiveness, etc.), molding processability, economic efficiency, etc. without departing from the gist of the present invention. Then, other layers may be laminated.
As the other layer that can be laminated in the solar cell protective material of the present invention, any layer that can be used for the solar cell protective material can be usually used. For example, a sealing material, a light collecting material, a conductive material, Layers such as a heat transfer material and a moisture adsorbing material can be laminated.
Various additives can be added to these other layers as necessary. Examples of the additive include, but are not limited to, an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, a colorant, a weathering stabilizer, an antiblocking agent, and an antioxidant. As the ultraviolet absorber, the weather resistance stabilizer and the antioxidant, the same materials as those used for the above-mentioned substrate can be used.

The thickness of the protective material for solar cells is not particularly limited, but is usually about 80 to 500 μm, preferably 100 to 350 μm, more preferably 200 to 320 μm, and still more preferably 250 to 300 μm. It is used in the form of a sheet.
In addition, the solar cell protective member of the present invention is preferably used in a roll shape from the viewpoint of processability, transportability, productivity, appearance protection, and the like, and is wound at least 50 m or more, preferably 100 m or more. It is desirable to be provided in the form of

(Moisture resistance of solar cell protective material)
As described above, the protective material for a solar cell of the present invention uses a moisture-proof film having an inorganic film as a base material and a moisture permeability of less than 0.1 [g / m ² · day]. The transmittance is preferably 0.1 [g / m ² · day] or less, and more preferably 0.05 [g / m ² · day] or less.
The solar cell protective material of the present invention is excellent in initial moisture resistance, and also excellent in moisture resistance and prevention of delamination even when stored in a high temperature and high humidity environment.

In addition, by using the pressure-sensitive adhesive, the moisture-proof property is the degree of decrease in moisture-proof property due to vacuum lamination and a continuous high-temperature and high-humidity environment by a pressure coker test according to JIS C 60068-2-66, that is, The water vapor transmission rate after the high temperature and high humidity environment / initial water vapor transmission rate) can be usually 25 or less, preferably 15 or less, more preferably 10 or less, and still more preferably 2 or less.
The “initial moisture resistance” of the protective material for solar cells 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 vacuum lameet conditions. It means the value before sex degradation 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”.

  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)”.

<Solar cell module, solar cell manufacturing method>
The solar cell protective material of the present invention can be used as a solar cell surface protective material as it is or by further bonding to a glass plate or the like.
A solar cell module can be produced by using the solar cell protective material of the present invention for the layer structure of a surface protective material such as a front sheet and a back sheet, and fixing the solar cell element together with a sealing material.

  As such a solar cell module, various types can be exemplified, and preferably, when the solar cell protective material of the present invention is used as a front sheet, a sealing material, a solar cell element, And a solar cell module manufactured using a back sheet. Specifically, the front sheet (protective material for solar cell of the present invention) / sealing material (sealing resin layer) / solar cell element / sealing. Forming material (encapsulating resin layer) / back sheet, and forming the encapsulant and the front sheet (the solar cell protective material of the present invention) on the solar cell element formed on the inner peripheral surface of the back sheet. A solar cell element formed on the inner peripheral surface of the front sheet (the solar cell protective material of the present invention), for example, an amorphous solar cell element formed on a fluororesin-based transparent protective material by sputtering or the like. And the like can be mentioned configuration, such as to form a sealing material and the back sheet on what was. In addition, the protective material for solar cells may be a sealing material / protective material integrated type formed by laminating a sealing material. By laminating the sealing material in advance, the work of individually laminating the front sheet, the sealing material, the power generation element, the sealing material, and the back sheet in the vacuum lamination process can be reduced, and the solar cell module manufacturing efficiency is improved. be able to.

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. -VI group compound semiconductor type, dye-sensitized type, organic thin film type, etc. are mentioned.
When a solar cell module is formed using the solar cell protective material in the present invention, the moisture resistance is less than 0.1 [g / (m ² · day)] in terms of water vapor transmission rate depending on the type of the solar cell power generation element. Appropriately selected according to the type of element, from a low moisture-proof film to a high moisture-proof film less than 0.01 [g / (m ² · day)], and using an adhesive having an appropriate tensile storage modulus and thickness And laminated.

  Although it does not specifically limit about each other member which comprises the solar cell module produced using the protective material for solar cells of this invention, For example, as a sealing material, ethylene-vinyl acetate copolymer weight Coalescence can be mentioned. Further, the solar cell protective material of the present invention may be used for both the front sheet and the back sheet. On the other hand, a single layer or a multilayer such as a sheet made of an inorganic material such as metal or glass or various thermoplastic resin films is used. These sheets may be used. Examples of the metal include tin, aluminum, and stainless steel, and examples of the thermoplastic resin film include single-layer or multilayer sheets of polyester, fluorine-containing resin, polyolefin, and the like. The surface of the Freon and the sheet and / or the back sheet can be subjected to a known surface treatment such as a primer treatment or a corona treatment in order to improve the adhesion between the sealing material and other members.

  The solar cell module produced using the solar cell protective material of the present invention is a front sheet (solar cell protective material of the present invention) / sealing material / solar cell element / sealing material / back sheet as described above. The configuration will be described as an example. The solar cell protective material, the sealing resin layer, the solar cell element, the sealing resin layer, and the back sheet 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 lower surface of the back sheet. 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.

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 solar cell protective material, the sealing resin layer, the solar cell element, the sealing of the present invention. It has the process of laminating | stacking a stop resin layer and a back sheet in order, and the process of vacuum-sucking them and carrying out thermocompression bonding. The step of vacuum suction and thermocompression bonding is, for example, a vacuum laminator, and the temperature is preferably 130 to 180 ° C, more preferably 130 to 150 ° C, the degassing time is 2 to 15 minutes, and the press pressure is 0.05 to 0. .1 MPa, pressing time is preferably 8 to 45 minutes, and more preferably 10 to 40 minutes.
Also, batch type manufacturing equipment, roll-to-roll type manufacturing equipment, and the like can be applied.

  The solar cell module produced using the solar cell protective material of the present invention is installed on a small solar cell represented by a mobile device, a roof or a roof, regardless of the type and module shape of the applied solar cell. It can be applied to various uses such as large solar cells, both indoors and outdoors. In particular, among electronic devices, it is suitably used as a protective material for solar cells for a flexible solar cell module such as a compound power generation element solar cell module or an amorphous silicon type.

  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.

(Physical property measurement)
(1) Tensile storage elastic modulus of pressure-sensitive adhesive layer A pressure-sensitive adhesive is applied on a silicone release PET film so as to have a thickness of 25 g / m ² , cured at 40 ° C. for 4 days, and then maintained at 150 ° C. for 30 minutes. An adhesive layer was formed. Thereafter, only the pressure-sensitive adhesive layer is taken out and stacked to a predetermined thickness to prepare a sample (length 4 mm, width 60 mm, thickness 200 μm). About the obtained sample, viscoelasticity measuring device manufactured by IT Measurement Co., Ltd., trade name Using a “viscoelastic spectrometer DVA-200”, the sample was applied to a sample from −100 ° C. to 180 ° C. in the transverse direction at a vibration frequency of 10 Hz, a strain of 0.1%, a heating rate of 3 ° C./min, and a spacing of 25 mm between chucks. The tensile storage elastic modulus (MPa) at 100 ° C. was determined from the obtained data.

(2) End face sealing state Glass, sealing material and protective materials for solar cells E-1 to E-6 are laminated in order so that the fluororesin film is on the exposed side, and the condition is 150 ° C. × 15 minutes. Then, vacuum lamination was performed, the state was observed, and the following criteria were evaluated.
(O) The sealing material reaches the end face of the fluororesin film width, and no extreme thinning occurs.
(X) The sealing material does not extend to the end face of the fluororesin film width, or the thickness of the reaching sealing material is small, and the end portion is thinned.

(3) Pressure cooker (PC) test After solar curing protective materials (E-1 to E-6) were vacuum-laminated by the above method, pressure cooker test LSK-500 manufactured by Tommy Seiko Co., Ltd. was used. After performing a pressure cooker test under the test (PC48) conditions of 105 ° C., 100% humidity and 48 hours, the water vapor transmission rate was measured.

(4) Pressure cooker (PC) delamination test After the protective materials for solar cells (E-1 to E-6) after curing were vacuum-laminated by the above method, pressure cooker test LSK-500 manufactured by Tommy Seiko Co., Ltd. Was used under the test conditions of 105 ° C. and 100% humidity.
The test time until the occurrence of delamination could be visually confirmed at the end face of the solar cell protective material was measured. Those in which the occurrence of delamination could not be confirmed in 90 hours were over 90 hours (> 90).

(5) Water vapor transmission rate The water vapor transmission rate of the moisture-proof film was measured by the following method as the water vapor transmission rate after the moisture-proof film was prepared and stored at 40 ° C for one week.
Moreover, about the protective material for solar cells (E-1 to E-6), the measured value after curing is the initial water vapor transmission rate, and after the curing, the protective material for glass, solar cell (fluorine resin film is exposed side) ), Heat treatment is performed at 150 ° C. for 30 minutes, and the measured value of each solar cell protective material after the pressure cooker test is performed under the condition (3) above is the water vapor permeation after the pressure cooker test. The rate value was used.
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 protective materials for each solar cell with a moisture permeable area of 10.0 cm x 10.0 cm square, a bag with about 20 g of anhydrous calcium chloride added as a hygroscopic agent and sealed on all sides was produced, and the bag was heated to 40 ° C relative humidity Place in a 90% thermo-hygrostat and measure the mass up to about 200 days at intervals of 72 hours or more. From the slope of the regression line between the elapsed time after the 4th day and the bag weight, the water vapor transmission rate (g / m ²・ Day) was calculated. The degree of decrease in moisture resistance was calculated by [water vapor permeability after pressure cooker test (PC48) / initial water vapor permeability].

<Structure film>
(Fluorine resin film)
As the fluororesin film, a tetrafluoroethylene / ethylene copolymer (ETFE) film (manufactured by Asahi Glass Co., Ltd., trade name: Aflex 50 MW1250 DCS, thickness 50 μm) having the following size was used.
A-1 A fluororesin film was cut to a width of 200 mm and a length of 200 mm and used. A-2 A fluororesin film was cut to a width of 230 mm and a length of 180 mm and used.
A-3 A fluororesin film was cut into a width of 200 mm and a length of 200 mm for use.
A-4 A fluorine resin film was cut into a width of 180 mm and a length of 180 mm for use.

(Adhesive)
B-1: Using a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, 90 parts by mass of butyl acrylate, 10 parts by mass of acrylic acid, 75 parts by mass of ethyl acetate, and 75 parts by mass of toluene 0.3 parts by mass of azobisisobutyronitrile was added to the mixed solution, and polymerization was performed at 80 ° C. for 8 hours in a nitrogen gas atmosphere. After completion of the reaction, the solid content was adjusted to 30% by mass with toluene to obtain a resin having a mass average molecular weight of 500,000. To 100 parts by mass of the obtained resin, 1 part by mass of Coronate L (trade name: Nippon Polyurethane Industry Co., Ltd., solid content: 75% by mass) is added as an isocyanate-based crosslinking agent to prepare an adhesive B-1. did. The results of measuring the tensile storage modulus at 100 ° C. are shown in Table 1.

B-2: Using a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen gas introduction tube, 40 parts by mass of butyl acrylate, 10 parts by mass of isobutyl acrylate, 40 parts by mass of methyl acrylate, 10 parts of acrylic acid 0.3 parts by mass of azobisisobutyronitrile was added to a mixed solution of parts by mass, 75 parts by mass of ethyl acetate and 75 parts by mass of toluene, and polymerized at 80 ° C. for 8 hours in a nitrogen gas atmosphere. After completion of the reaction, the solid content was adjusted to 30% by mass with toluene to obtain a resin having a mass average molecular weight of 500,000. To 100 parts by mass of the obtained resin, 1 part by mass of Coronate L (trade name: manufactured by Nippon Polyurethane Industry Co., Ltd., solid content: 75% by mass) is added as an isocyanate-based crosslinking agent to prepare an adhesive B-2. did. The results of measuring the tensile storage modulus at 100 ° C. are shown in Table 1.

(Dampproof film)
As a base material, a biaxially stretched polyethylene naphthalate film (made by Teijin DuPont, “Q51C12”) having a thickness of 12 μm is used, 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 having a thin film was obtained and cut into a width of 180 mm and a length of 180 mm for use. The produced moisture-proof film had a water vapor transmission rate 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.

(Adhesive and adhesive coating solution)
HD1013 manufactured by Rock Paint Co., Ltd. is used as the main component containing the polyurethane polyol component, and H62 manufactured by Rock Paint Co., Ltd. is used as the curing agent containing the aliphatic hexamethylene diisocyanate component, resulting in a weight ratio of 10: 1. Were mixed with each other and diluted with ethyl acetate so that the solid content concentration was 30% to prepare an adhesive coating solution.

(Encapsulant)
Brand name: EVASKY S11 (thickness 500 μm, melting point 69.6 ° C.) manufactured by Bridgestone Corporation was used.

(Glass)
A cover glass TCB09331 (3.2 mm thickness) manufactured by AGC Fabritech Co., Ltd. was used and cut into glass of the same size as the fluororesin film used in each of the examples and comparative examples.

Example 1
An adhesive B-1 was applied to a 38 μm silicone release PET film so that the thickness was 20 μm in terms of solid content, and dried to form an adhesive layer (width 180 mm, length 200 mm). The formed adhesive surface adhered to SiO _X surface of the moisture-proof film, then peeling off the silicone release PET film was cured for 4 days with the other on one of the adhesive surface bonded to a fluorine-based resin film A-1 combined 40 ° C. Thickness The protective material E-1 for solar cells of 82 micrometers was created. Laminate glass, encapsulant, and solar cell protective material E-1 (fluorine resin film exposed side) in this order, vacuum laminate under conditions of 150 ° C x 15 minutes, and wrap around the end face of the encapsulant After that, a pressure cooker test and a pressure cooker delamination test were performed, and a water vapor transmission rate and a delamination generation time were measured. The results are shown in Table 1.

Example 2
A protective material E-2 with a thickness of 82 μm was prepared in the same manner as in Example 1 except that A-2 was used as the fluorine resin film. After that, it is laminated in the order of glass, sealing material, and solar cell protective material E-2 (fluorine resin film exposed side), and vacuum laminating is performed at 150 ° C for 15 minutes. After that, a pressure cooker test and a pressure cooker delamination test were performed, and a water vapor transmission rate and a delamination generation time were measured. The results are shown in Table 1.

Example 3
A protective material E-3 having a thickness of 82 μm was prepared in the same manner as in Example 1 except that A-3 was used as the fluorine resin film. After that, it is laminated in the order of glass, sealing material, and solar cell protective material E-2 (fluorine resin film exposed side), and vacuum laminating is performed at 150 ° C for 15 minutes. After that, a pressure cooker test and a pressure cooker delamination test were performed, and a water vapor transmission rate and a delamination generation time were measured. The results are shown in Table 1.

Example 4
A pressure-sensitive adhesive B-1 was applied to a 38 μm-thick silicone release PET film so that the thickness was 20 μm in terms of solid content, and dried to form a pressure-sensitive adhesive layer (width 180 mm, length 200 mm). The formed adhesive surface adhered to SiO _X surface of the moisture-proof film, then peeling off the silicone release PET film was stuck a fluorine resin film A-1 to the other adhesive face.
Next, an adhesive coating liquid was applied to a polyethylene terephthalate film having a thickness of 188 μm so as to have a thickness of 7 μm and dried to form an adhesive surface. The moisture-proof film surface of the laminate prepared above was bonded to the adhesive surface and cured at 40 ° C. for 4 days to prepare a solar cell protective material E-4 having a thickness of 287 μm. Laminate glass, sealing material, and solar cell protective material E-4 (fluorine resin film exposed side) in this order, vacuum laminate under conditions of 150 ° C x 15 minutes, and wrap around the end face of the sealing material After that, a pressure cooker test and a pressure cooker delamination test were performed, and a water vapor transmission rate and a delamination generation time were measured. The results are shown in Table 1.

Example 5
A solar cell protective material E-5 having a thickness of 82 μm was prepared in the same manner as in Example 1 except that the adhesive B-1 of Example 1 was changed to B-2, and then glass, a sealing material, and solar cell protection Laminate in order of material E-5 (fluorine resin film exposed side), vacuum laminate under conditions of 150 ° C x 15 minutes to evaluate the entrainment of the end face of the sealing material, then pressure cooker test, pressure cooker A delamination test was performed, and the water vapor transmission rate and the delamination generation time were measured. The results are shown in Table 1.

Comparative Example 1
A solar cell protective material E-6 having a thickness of 82 μm was prepared in the same manner as in Example 1 except that the fluorine-based film A-1 of Example 1 was changed to A-4, and then glass, a sealing material, and a solar cell Laminate in order of protective material E-6 (fluorine resin film exposed side) and vacuum laminate under conditions of 150 ° C x 15 minutes to evaluate the entrainment of the end face of the sealing material, then pressure cooker test, pressure A cooker delamination test was conducted to measure water vapor transmission rate and delamination generation time. The results are shown in Table 1.

  As is apparent from the results in Table 1, Examples 1 to 5 within the scope of the present invention are all excellent in moisture resistance and prevention of delamination, and the width of each layer forming the protective material for solar cells is the present invention. The comparative example 1 which is not in the range of the above was inferior in the delamination prevention performance.

DESCRIPTION OF SYMBOLS 1 ... Fluorine-based resin film 2 ... Adhesive layer 3 ... Moisture-proof film 4 ... Sealing material 5 ... Glass

Claims (6)

At least a fluorine resin film, a pressure-sensitive adhesive layer, and a sun formed by laminating a moisture-proof film having an inorganic film on at least one surface of a substrate and having a water vapor transmission rate of less than 0.1 [g / m ² · day] A solar battery comprising a protective material for a battery, wherein a ratio (B / A) of a maximum width B of a protective material constituting layer other than the fluorine resin film to a width A of the fluorine resin film is less than 1. Battery protection material.   The said B / A is 0.7-0.98, The protective material for solar cells of Claim 1 characterized by the above-mentioned.   The protective material for solar cells according to claim 1 or 2, wherein the layer having the maximum width of the protective material constituting layer other than the fluororesin film is a moisture-proof film. The adhesive layer has a tensile storage elastic modulus of 5.0 × 10 ⁴ to 5.0 × 10 ⁵ Pa at 100 ° C., a frequency of 10 Hz, and a strain of 0.1%, and a thickness of 13 μm or more. The solar cell protective material according to any one of claims 1 to 3.   The film roll by which the protective member for solar cells in any one of Claims 1-4 is wound up 100m or more.   The solar cell module produced using the protective material for solar cells in any one of Claims 1-4.