JP6589553B2 - One-pack type easy-adhesive for solar cell protective sheet, easy-adhesive sheet, and solar cell module - Google Patents

Description

  The present invention relates to a one-pack type easy-adhesive for a solar battery back sheet excellent in adhesiveness between a solar cell sealing material and a base sheet, an easy-adhesive sheet excellent in adhesive strength and heat-and-moisture resistance, and the sheet. The present invention relates to a solar cell module.

  In recent years, the depletion of fossil fuels such as oil and coal has been threatened, and there is an urgent need to develop alternative energy that can be obtained from these fossil fuels. Among such fossil fuel alternative energy, solar power generation capable of directly converting solar energy into electric energy is being put into practical use as a new energy source that is semi-permanent and non-polluting, and is actually used. The improvement in price / performance ratio is remarkable, and it is highly expected as a clean energy source.

  The solar cell used for photovoltaic power generation is the heart of a photovoltaic power generation system that directly converts sunlight energy into electrical energy, and is composed of semiconductors such as silicon, and its structure is a photovoltaic cell. Are connected in series and in parallel, and various packaging is applied to form a unit to protect the cells. A unit incorporated in such a package is called a solar cell module. In general, a light-receiving surface that is exposed to sunlight is covered with a surface protection member such as a glass plate, and a gap between the solar cell and the surface protection member is made of a thermoplastic resin. It has the structure which sealed and also arrange | positioned the back surface protection sheet.

  Since such a solar cell module is normally used outdoors for a long period of about 30 years, the material for sealing the solar cell and the surface protection member is highly transparent and moisture resistant. An excellent ethylene-vinyl acetate copolymer resin is often used, and the back protective sheet (back sheet) is made of a polyester sheet such as polyethylene terephthalate resin, and an adhesive is applied to both sides thereof. In addition, laminated sheets obtained by laminating fluorine resin sheets having excellent weather resistance such as polyvinyl fluoride, polyvinylidene fluoride, polytetrafluoroethylene, and polychlorotrifluoroethylene are widely used.

  Although a laminated sheet provided with a fluorine-based resin sheet in this way becomes a back sheet having weather resistance and sufficient practical adhesive strength, ethylene constituting a sealing material for solar cells by long-term use in a humid heat environment -The strength of the interface with the vinyl acetate copolymer decreases over time, and the long-term reliability and durability that are required in recent years cannot be sufficiently met.

  Therefore, in recent years, instead of laminating the above-described fluorine-based resin sheet on the surface of the solar battery back sheet that is in contact with the solar battery cell sealing material, there is a means for coating the surface of the base material sheet with an easy adhesive. Widely adopted.

  However, the back sheet using the easy-adhesive as an alternative to the fluororesin sheet cannot protect the solar cell from moisture and external factors when the back sheet peels off. Therefore, the easy adhesive layer is required to have a high degree of adhesion and durability. Therefore, it was necessary for the easy-adhesive to ensure adhesion to the solar cell sealing material and at the same time to ensure adhesion to a substrate sheet such as a PET sheet.

  Thus, conventionally, as a technique for further improving the adhesion durability when using a sheet using an easy-adhesive as a protective sheet for a solar cell sealant, for example, Patent Document 1 below mainly describes a solar cell. As a surface protective sheet on the light-receiving surface side, for example, a two-component type containing, as essential components, an acrylic polymer having an acryloyl group and a hydroxyl group, and a polyisocyanate component obtained by reacting acrylic acid with a hydroxy group-containing acrylic oligomer A solar cell protective sheet using an adhesive as an easy-adhesive in contact with a sealant is disclosed, and an example in which this protective sheet is also applied to a solar cell backsheet is disclosed (see Patent Document 1 below).

  However, the solar cell protective sheet using the easy-adhesive described in Patent Document 1 has a good initial adhesive strength after aging, but is a two-component curable type in which a reaction between a polyol and an isocyanate is a main curing reaction. Therefore, the cured shrinkage is large and the cured product is easily distorted, and a sufficient adhesive strength cannot be obtained after being exposed to a humid heat environment for a long time. In addition, aging is required to completely cure the sheet during manufacture, and the sheet productivity is inferior, and blocking is likely to occur during storage of the sheet after manufacture. In addition, when the solar cell protective sheet described in Patent Document 1 is used as a solar cell backsheet, the easy-adhesive layer is an alternative to the fluorine-based resin sheet, and thus once peeled off in a moist heat environment. In this case, as described above, the sealing agent of the solar battery cell is directly exposed to an external environment such as water, air, and moisture, and thus suffers damage such as a decrease in battery output.

JP2013-136665A

  Therefore, the problem to be solved by the present invention is that when the solar cell sealing material and the solar cell protective sheet are bonded, the sheet can be applied by a simple method and sealed after wet heat. It is obtained by applying the one-component easy-adhesive for a solar cell protective sheet, which can dramatically improve the adhesive strength between the stopper and the sheet, particularly the adhesive strength under wet heat environment. The object is to provide an adhesive sheet and a solar cell module using the sheet.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have developed a lacquer-like adhesive obtained by diluting a (meth) acryloyl group-containing (meth) acrylic polymer having a specific iodine value with an organic solvent, By applying the resin layer on the surface of the solar cell protective sheet, an adhesive protective sheet can be obtained simply by a solvent drying process, and the adhesive-coated surface is used as a sealant. By manufacturing a laminated solar cell module so as to be in contact with each other, it has been found that excellent adhesiveness with the solar cell sealing material, in particular, adhesiveness after wet heat is developed, and the present invention has been completed.

  That is, the present invention includes a (meth) acryloyl group-containing (meth) acrylic polymer (A) having an iodine value of 70 to 130 g / 100 g and an organic solvent (B) as essential components. The present invention relates to a one-component easy-adhesive for protective sheets.

  The present invention further relates to a solar cell protective sheet obtained by applying the one-pack type easy-adhesive for a solar cell backsheet onto the surface layer of a base sheet having a fluororesin layer as a surface layer, and then drying the same.

  The present invention further includes a solar battery cell, a surface protective base material, a solar cell sealing material, and a back sheet as essential constituent elements, and the back sheet has a fluororesin layer as a surface layer (I ) Is applied to the solar cell protective sheet, and then dried, and the easy adhesive layer is sealed for solar cells. It is related with the solar cell module characterized by the front protection sheet | seat being arrange | positioned so that a material may be contact | connected.

  According to the present invention, when the solar cell sealing material and the solar cell protective sheet are bonded, the sheet can be applied by a simple method, and the sealing agent after wet heat and the sheet The one-pack type easy-adhesive for solar cell protective sheet capable of dramatically improving the adhesive strength of the adhesive, particularly the wet-heat environment, the adhesive sheet obtained by applying the one-part easy-adhesive, and the A solar cell module using a sheet can be provided.

FIG. 1 is a cross-sectional view of an example of the solar cell module of the present invention.

  The one-pack type easy-adhesive for solar cell protective sheet of the present invention requires a (meth) acrylic polymer (A) having a (meth) acryloyl group and an iodine value of 70 to 130 g / 100 g, and an organic solvent (B). It is characterized by being a component. In the present invention, the (meth) acrylic polymer having a high iodine value is used, and the solar cell protective sheet is coated and dried as a lacquer-like adhesive without substantially curing the solar cell. By adhering so as to be in contact with the cell sealant, a cured product having appropriate hardness and flexibility is formed, and the surface of the sealant and the fluororesin surface are formed without causing distortion in the cured product layer. It is possible to develop excellent moisture and heat resistance. Moreover, since the one-pack type easy-adhesive for solar cell protection sheets is a one-pack type, aging after coating is unnecessary, and an adhesive protective sheet can be produced by a simple method, or in a roll shape. Blocking during storage is also unlikely to occur.

  The (meth) acrylic polymer (A) having a (meth) acryloyl group used here is characterized by having an iodine value in the range of 70 to 130 g / 100 g as described above, and the iodine value is less than 70 g / 100 g. In such a case, sufficient moisture and heat resistance cannot be obtained. On the other hand, if it exceeds 130 g / 100 g, the curing shrinkage / cohesive force becomes excessively high, and the cured product layer tends to be distorted. Adhesive force with time on the surface is reduced.

  Specifically, such a (meth) acrylic polymer (A) comprises a molar ratio [(a1) / (a2)] of glycidyl (meth) acrylate (a1) and alkyl (meth) acrylate (a2). Is equivalent to an epoxy group-containing (meth) acrylic resin obtained by copolymerization at a ratio of 90/10 to 60/40, a compound having a carboxyl group and a (meth) acryloyl group, or an anhydride thereof (a3). What reacted with the ratio [epoxy group / acid group] will be 1/1 to 1 / 1.5 is mentioned.

  Here, as alkyl (meth) acrylate (a2), methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, isoamyl (meth) acrylate, neopentyl (meth) acrylate, n-hexyl (meth) acrylate, n- Heptyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) a Relate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, cyclohexyl (meth) acrylate, Examples include bornyl (meth) acrylate and isobornyl (meth) acrylate. Of these, methyl is particularly preferred because of its good reactivity with glycidyl (meth) acrylate (a1) and subsequent reactivity with the epoxy group-containing (meth) acrylic resin and the carboxyl group in (a3). (Meth) acrylate esterified with an alkyl group having 1 to 3 carbon atoms, such as (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, and the like is preferable.

  As a method of copolymerizing glycidyl (meth) acrylate (a1) and alkyl (meth) acrylate (a2), specifically, benzoyl peroxide, azobisisobutyronitrile, 2,2′-azobis ( 2-methylbutyronitrile), t-butylperoxy-2-ethylhexanoate, 1,1-di (t-butylperoxy) cyclohexane, t-amylperoxy-2-ethylhexanoate, t-butyl It can be produced by a radical polymerization reaction using a radical polymerization initiator such as peroctoate, di-t-butyl peroxide or t-butyl perbenzoate. In this case, these radical polymerization initiators may be used alone or in combination of two or more. Such radical polymerization reaction is usually carried out in the range of 60 to 150 ° C. in hydrocarbon solvents such as toluene, xylene, cyclohexane, n-hexane, and octane; methyl acetate, ethyl acetate, n-butyl acetate, isobutyl acetate. , Ester solvents such as n-propyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethoxyethyl propionate; ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, propylene glycol Glycol ether solvents such as monomethyl ether; ether solvents such as diethylene glycol dimethyl ether; acetone, methyl ethyl ketone, methyl isobutyl ketone, Organic solvent such as a ketone solvent such as hexanone, or it is preferably carried out in two or more mixed solvent of these.

  A glycidyl group-containing acrylic resin thus obtained is reacted with a compound having a carboxyl group and a (meth) acryloyl group or its anhydride (a3), and has an iodine value of 70 to 130 g / 100 g. A (meth) acryloyl group-containing (meth) acrylic polymer (A) is obtained.

  Specific examples of the compound having a carboxyl group and a (meth) acryloyl group or the anhydride (a3) used herein include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, and citraconic acid. Among these, acrylic acid or methacrylic acid is preferable from the viewpoint of excellent reactivity.

  Here, the reaction between the glycidyl group-containing acrylic resin, the compound having a carboxyl group and a (meth) acryloyl group or the anhydride (a3) thereof has an equivalent ratio [epoxy group / acid group] of 1/1 to 1 / The (meth) acryloyl polymer (A) which can be reacted at a ratio of 1.5 can be easily adjusted to a predetermined range of iodine, and the unreacted component (a3) is preferably reduced.

  The (meth) acrylic polymer (A) having a (meth) acryloyl group thus obtained has an iodine value in the range of 70 to 130 g / 100 g. Particularly, the iodine value is 85 to 120 g / 100 g from the viewpoint of heat and humidity resistance. It is preferable that it is the range of these. Here, the iodine value is a value measured by the Wiis method.

  The (meth) acrylic polymer (A) preferably has a double bond concentration (mmol / g) in the range of 2.5 to 5.5 from the viewpoint of adhesive strength. Mn) is preferably in the range of 5,000 to 500,000 from the viewpoint of adhesive strength and blocking resistance.

  Here, the number average molecular weight (Mn) of the (meth) acrylic polymer (A) in the present invention is a value measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: HLC-8220GPC manufactured by Tosoh Corporation
Column: TSK-GUARDCOLUMN SuperHZ-L manufactured by Tosoh Corporation
+ Tosoh Corporation TSK-GEL SuperHZM-M x 4
Detector: RI (differential refractometer)
Data processing: Multi-station GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate: 0.35 ml / min Standard: Monodispersed polystyrene Sample: Filtered 0.2% by mass tetrahydrofuran solution in terms of resin solids with a microfilter (100 μl)

  Next, as the organic solvent (B) used in the present invention, the solvent used in the synthesis of the (meth) acrylic polymer (A) can be used as it is, and further, the (meth) acrylic polymer (A) is separately used. You may mix | blend and dissolve | melt. Examples of the organic solvent (B) include solvents that can be used for the synthesis of the (meth) acrylic polymer (A), hydrocarbon solvents such as toluene, xylene, cyclohexane, n-hexane, and octane; methyl acetate, acetic acid Ester solvents such as ethyl, n-butyl acetate, isobutyl acetate, n-propyl acetate, amyl acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, ethoxyethyl propionate; ethylene glycol monoethyl ether, ethylene glycol monomethyl Glycol ether solvents such as ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether; ether solvents such as diethylene glycol dimethyl ether; acetone, methyl ethyl ketone Methyl isobutyl ketone, other ketone solvents such as cyclohexanone, tetrahydrofuran (THF), cyclic ether compounds such as dioxolane. These may be used alone or in combination of two or more. Among these, an ester solvent or a glycol ether solvent is particularly preferable from the viewpoint of excellent compatibility with the (meth) acrylic polymer (A).

  In the present invention, by using the organic solvent (B), the solid content concentration of the one-pack type easy-adhesive for a solar cell protective sheet can be appropriately adjusted. The blending amount of the organic solvent is not particularly limited. For example, the solid content concentration in the one-pack type easy-adhesive for a solar cell protective sheet (the (meth) acrylic polymer (A) and other solids) It is preferable from the point that the workability of the adjustment of the one-component easy-adhesive agent and the subsequent coating is good.

  The one-pack type easy-adhesive for solar cell protective sheet of the present invention comprises the above-mentioned (meth) acrylic polymer (A) and organic solvent (B) as essential components, and does not particularly use a polymerization initiator. Both can be polymerized by a peroxide present in the solar cell encapsulant (EVA), but a polymerization initiator for the reaction may be used in combination. Examples of the polymerization initiator that can be used here include benzoyl peroxide, azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), t-butylperoxy-2-ethylhexanoate, 1,1-di (t-butylperoxy) cyclohexane, t-amylperoxy-2-ethylhexanoate, t-butylperoctoate, di-t-butylperoxide or t-butylperbenzoate It is done. These radical polymerization initiators may be used alone or in combination of two or more.

  In addition, the one-pack type easy-adhesive for solar cell protective sheet of the present invention further uses the (meth) acrylic polymer (A) when the adhesive layer absorbs moisture by using the polyfunctional epoxy compound (C) together. ) Can be captured by the epoxy group in the polyfunctional epoxy compound, and the heat-and-moisture resistance of the adhesive layer can be further improved.

  Such a polyfunctional epoxy compound (C) is preferably an epoxy compound having a molecular weight in the range of 200 to 1,000. That is, when the molecular weight is 200 or more, in addition to moisture and heat resistance, the adhesive strength to the substrate sheet is further improved. When the molecular weight is 1,000 or less, the (meth) acrylic polymer (A) The compatibility with is good.

  Specific examples of such a polyfunctional epoxy compound (C) include 1,6-hexanediol diglycidyl luter, 1,4-butanediol diglycidyl ether, trimethylolpropane triglycidyl ether, diethylene glycol diglycidyl ether, and the like. Acyclic aliphatic polyglycidyl ether; cyclohexanedimethanol diglycidyl ether, 3 ′, 4′-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, ε-caprolactone modified 3 ′, 4′-epoxycyclohexylmethyl-3 , 4-epoxycyclohexanecarboxylate, cycloaliphatic skeleton-containing epoxy compounds such as hydrogenated bisphenol A type epoxy resins; bisphenol A type epoxy resins, bisphenol F type epoxy resins, etc. Scan phenol epoxy resin; biphenyl type epoxy resins such as tetramethyl biphenyl type epoxy resin; dicyclopentadiene - phenol addition reaction type epoxy resins. These may be used alone or in combination of two or more. Among these, trimethylolpropane triglycidyl ether and bisphenol type epoxy resin are preferable in terms of obtaining a resin composition excellent in base material adhesion and initial adhesive strength under wet heat conditions, and bisphenol type epoxy resin is preferably epoxy. Equivalent 200-400 g / eq. It is preferable from the point which is excellent in adhesive strength and compatibility with the said (meth) acrylic polymer (A).

  The said polyfunctional epoxy compound (C) is mix | blended in the ratio used as 4.0-30.0 mass parts with respect to 100 mass parts of solid content of the one-pack type adhesive agent for solar cell protection sheets of this invention. However, it is preferable from the viewpoints of heat and moisture resistance and blocking resistance.

  As described above, the one-pack type easy-adhesive for solar cell protective sheet of the present invention is a one-pack type easy-to-adhesive, so that it is difficult to develop good adhesive strength and further adhesiveness by appropriate curing shrinkage. Although it is excellent in the adhesive force between the fluororesin surface and the sealing agent (EVA), a polyisocyanate component may be blended to increase the crosslinking density within a range not impairing the effects of the present invention.

  Examples of the polyisocyanate component that can be used here include aliphatic diisocyanates such as 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,8-octamethylene diisocyanate, and L-lysine diisocyanate, or fats. Examples thereof include cyclic polyisocyanates.

  Examples of the alicyclic polyisocyanate include alicyclic diisocyanates such as hydrogenated 4,4'-diphenylmethane diisocyanate (hydrogenated MDI), isophorone diisocyanate, norbornene diisocyanate, and the like.

  Examples of the aromatic polyisocyanate include 4,4′-diphenylmethane diisocyanate (MDI), 4,4′-biphenyl diisocyanate tridenic diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, p- Aromatic diisocyanates such as tetramethylxylene diisocyanate, m-tetramethylxylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate Etc.

  In addition, triisocyanate or higher polyisocyanate is also exemplified. Specifically, for example, triphenylmethane triisocyanate, 1,6,11-undecane triisocyanate, 4,4 ′, 4 ″ -triphenylmethane triisocyanate, 2,4,4′-biphenyl triisocyanate, 2,4,4′-diphenylmethane triisocyanate, polymethylene phenyl isocyanate and the like can be mentioned.

  Furthermore, the isocyanurate type polyisocyanate, adduct type polyisocyanate, burette type polyisocyanate, and uretdione type polyisocyanate obtained using the said polyisocyanate compound are mentioned.

  It is preferable that the compounding quantity is a ratio used as 15 mass parts or less with respect to 100 mass parts of solid content of a (meth) acrylic polymer (A).

  The one-pack type easy-adhesive for solar cell protective sheet of the present invention, when used as a one-pack type easy-adhesive for solar cell backsheet, in addition to the above-described components, various inorganic pigments, organic pigments, or carbon Black, filler, ultraviolet absorber, antioxidant and / or light stabilizer can be contained.

  Among the above compounded materials, it is particularly preferable to use titanium dioxide as the inorganic pigment from the viewpoint that the surface of the solar battery cell back sheet is white, and sunlight is reflected to increase the power generation efficiency of the solar battery cell. Further, when emphasizing the design property, it is preferable to blend carbon black.

  For example, titanium dioxide having a mean particle size in the range of 0.1 to 1.5 μm is preferable. Titanium dioxide having an average particle size of 1.5 μm or less is preferable because the surface smoothness of the cured coating film is good.

  Titanium dioxide with an average particle size of 0.1 to 1.5 μm takes into account the toughness of the cured coating film itself and the adhesion that can follow the flexibility of the substrate to be coated, depending on the desired level of weather resistance In addition, it may be added to the main agent and / or the curing agent, but is preferably 25 to 900 parts by weight per 100 parts by weight in total in terms of non-volatile content of all curable components in terms of excellent weather resistance. However, it is more preferable to use 60 to 400 parts by weight in that the whiteness can be as high as when a fluororesin is used.

  Moreover, the said filler can be used as an antiblocking agent, and specifically, a silica with a mean particle diameter of 1-20 micrometers, a resin bead, etc. are mentioned. The amount of the filler used is in the range of 0.1 to 10.0 parts by weight per 100 parts by weight in terms of the nonvolatile content of all curable components, and can impart blocking resistance without deteriorating the adhesive performance. It is preferable from the point.

  As described above, the one-pack type easy-adhesive for a solar cell protective sheet of the present invention is applied to the base sheet for the backsheet that protects the solar cells of the solar cell module, thereby providing good easy-adhesion performance. And can exhibit excellent adhesive strength and heat-and-moisture resistance. In addition, the one-component easy-adhesive of the present invention is applied not only to the back sheet but also to the base sheet of the sheet when using a transparent resin sheet that substitutes for the glass plate for solar cell surface protection. Moreover, the easily adhesive performance with respect to a photovoltaic cell sealing material can also be expressed.

Here, the amount of the one-pack type easy-adhesive for solar cell protective sheet of the present invention applied to the base sheet for backsheet is not particularly limited, but is, for example, 1 to ²⁰ g / m ² . It is preferable that it is in the range of -10 g / m ² in that excellent weather resistance can be imparted with a small amount. For this coating, for example, a gravure coater, a micro gravure coater, a reverse coater, a bar coater, a roll coater, a die coater or the like can be used.

  The one-pack type easy-adhesive for solar cell protective sheet of the present invention expresses good adhesion performance to the base sheet for back sheet, but if necessary, for the purpose of imparting further adhesive strength, You may surface-treat to the surface which forms the cured coating film of base material sheets, such as a polyester resin film. Examples of the surface treatment include corona treatment, plasma treatment, ozone treatment, flame treatment, and radiation treatment.

  The base sheet for the solar battery back sheet used here is a polyester resin sheet such as a polyethylene terephthalate sheet, polybutylene terephthalate sheet or polynaphthalene terephthalate; a polyolefin sheet such as a polyethylene sheet, a polypropylene sheet or a polycyclopentadiene sheet; Vinyl fluoride sheet, polyvinylidene fluoride sheet, polytetrafluoroethylene sheet, tetrafluoroethylene-6 fluoropropylene copolymer (FEP) sheet, ethylene-4 fluoroethylene copolymer (ETFE) sheet, ethylene-tetrafluoro Fluorine resin sheet such as ethylene copolymer sheet; Acrylic resin sheet such as polyacrylonitrile, polymethylmethacrylate, etc .; Composite sheets made by laminating fluororesin sheets, composite sheets having a coating layer formed by applying a highly weather-resistant paint such as “Lumiflon” manufactured by Asahi Glass Co., Ltd. to one or the surface of the polyester resin sheet. Is mentioned. Furthermore, the composite sheet etc. which have the vapor deposition layer by which the vapor deposition film etc. which vapor-deposited the metal oxide and the non-metallic inorganic oxide on the said various sheets are laminated | stacked are mentioned.

  Here, as the deposited metal oxide or non-metallic inorganic oxide, for example, oxides such as silicon, aluminum, magnesium, calcium, potassium, tin, sodium, boron, titanium, lead, zirconium, yttrium can be used. . Alkali metal and alkaline earth metal fluorides can also be used, and these can be used alone or in combination. Physical vapor deposition methods such as vacuum vapor deposition and ion plating, and chemical vapor deposition methods such as plasma CVD. The thing vapor-deposited using is mentioned.

  The thickness of the above-described base sheet for backsheet is preferably in the range of, for example, 10 to 400 μm. However, the one-pack type easy-adhesive for solar cell protective sheet of the present invention is applied in a small amount and for a short time at low temperature. It is preferable that the thickness is in the range of 80 to 300 μm because it exhibits excellent adhesion without giving any influence such as warping or settling on the base material and can provide excellent weather resistance.

  In addition, the base sheet for the back sheet is further provided with a barrier property by disposing a film layer or a coat layer such as a metal foil or a weather resistant resin layer between a plurality of base sheet. Also good.

  Here, examples of the metal foil include thin films such as aluminum, aluminum oxide, silicon oxide, tin oxide, and magnesium oxide. Among these, aluminum foil is preferable from the viewpoint of corrosion resistance. The thickness is preferably 10 μm to 100 μm, more preferably 20 μm to 50 μm. Various conventionally known adhesives can be used for laminating the metal foil.

  As described above, the one-pack type easy-adhesive for a solar cell protective sheet of the present invention has an adhesive property between an ethylene-vinyl acetate copolymer resin, which is a sealing agent for solar cells, and a fluorine-based resin having excellent weather resistance. From the above viewpoint, among the various substrate sheets described above, fluorine resin sheets or fluorine on the surface layer are particularly excellent, and the adhesive strength after wet heat is particularly good. A composite sheet having a resin layer is preferable. A composite sheet having a structure in which the fluororesin sheet is laminated on both sides of a polyester resin sheet is particularly preferable. The polyester resin sheet and the fluororesin sheet when the composite sheet is manufactured may be laminated using, for example, a general-purpose urethane adhesive.

  Moreover, when using the composite sheet which makes this polyester-type resin sheet and the said fluororesin sheet essential, it is preferable from the point of sheet strength that thickness is 50-300 micrometers in the polyester-type resin sheet, on the other hand, a fluororesin The thickness of the sheet is preferably in the range of 10 to 100 μm from the viewpoint of weather resistance.

  Next, when the one-pack type easy-adhesive for solar cell protective sheet of the present invention is applied to the solar cell surface protective resin sheet, the surface protective resin sheet that can be used is the same as the case of the back sheet. Polyester resin sheet such as polyethylene terephthalate sheet, polybutylene terephthalate sheet, polynaphthalene terephthalate; polyolefin sheet such as polyethylene sheet, polypropylene sheet, polycyclopentadiene sheet, polyvinyl fluoride sheet, polyvinylidene fluoride sheet, polytetrafluoroethylene sheet Fluororesin sheets such as tetrafluoroethylene-6 fluoropropylene copolymer (FEP) sheet, ethylene-tetrafluoroethylene copolymer (ETFE) sheet, ethylene-tetrafluoroethylene copolymer sheet; Acrylonitrile, acrylic resin sheet such as polymethyl methacrylate; and polycarbonate.

  Among these, as in the case of the base sheet for back sheet, a fluorine resin sheet or a composite sheet having a fluorine resin layer on the coated surface is preferable.

  The above-described one-pack type easy-adhesive for solar cell protective sheet of the present invention is coated on the base sheet for back sheet or the base sheet for surface protection described in detail above and cured, thereby adhering the present invention. Sheet.

  Here, the curing reaction can be performed, for example, under conditions of 25 ° C. to 60 ° C. for 1 day to 5 days.

  The solar cell module using the adhesive sheet of the present invention described above will be described based on FIG. 1 which is a cross-sectional view of the module. For example, the solar cell (A), the surface protection base material (B), the solar cell The battery cell encapsulant (D) and the back sheet (E) are essential components, and the back sheet (E) is formed on the base sheet (a) and the base sheet (a). The adhesive layer (b), which is a cured product of the one-pack type easy-adhesive for a solar cell protective sheet of the present invention, has an essential layer structure, and the adhesive layer (b) is sealed for solar cells. The thing by which the said back seat | sheet (E) is arrange | positioned so that a stop material (D) may be mentioned is mentioned. Here, as described above, the surface protective substrate (B) is formed of a resin sheet and a cured layer of the one-pack type easy-adhesive for a solar cell protective sheet of the present invention formed on the resin sheet. A composite film in which the cured layer is disposed so as to be in contact with the sealing material (D) may be used.

  Here, examples of the battery surface protective material (B) include a glass plate, a plastic plate of polycarbonate or polyacrylate, and the like as described above. When polycarbonate or polyacrylate is used, good adhesiveness can be expressed by applying the one-pack type easy-adhesive for solar cell protective sheet of the present invention to the surface in contact with the sealant, but the transparency From the viewpoints of weather resistance and toughness, a glass plate is preferred. Furthermore, white glass with high transparency is preferable among the glass plates.

  Moreover, ethylene vinyl acetate resin (EVA) can be used for the sealing agent (D) used for the solar cell module of this invention. It is preferable that such a sealing material (D) contains an organic peroxide in the sealing agent (D) because the crosslinking reaction of the one-component easy-adhesive is promoted.

  Further, as the solar cell (A), for example, a single crystal silicon solar cell element, a polycrystalline silicon solar cell element, a single junction type, an amorphous silicon type solar cell element constituted by a tandem structure type, gallium, etc. III-V compound semiconductor solar cell elements such as arsenic (GaAs) and indium phosphorus (InP), II-VI compound semiconductor solar cell elements such as cadmium tellurium (CdTe), copper / indium / selenium system (CIS system), Copper / indium / gallium / selenium-based (CIGS-based), copper / indium / gallium / selenium / sulfur-based (CIGS-based) I-III-VI group compound semiconductor solar cell elements, dye-sensitized solar cell elements, organic A solar cell element etc. are mentioned.

  The method for producing such a solar cell module is, for example, an ethylene vinyl acetate resin (EVA) sheet serving as a sealing material, a plurality of solar cells (A), an ethylene vinyl acetate resin on the battery surface protective material (B). (EVA) sheet, the back sheet | seat (E) of this invention is arrange | positioned, the method of heating while evacuating and melt | dissolving two EVA sheets and sealing a solar cell element is mentioned. At this time, the plurality of solar cell elements are joined in series by the interconnector (C).

  Hereinafter, the present invention will be described more specifically with reference to examples. Unless otherwise specified, “part” is “part by weight” and “%” is “% by weight”.

  In Examples of the present application, the number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: HLC-8220GPC manufactured by Tosoh Corporation
Column: TSK-GUARDCOLUMN SuperHZ-L manufactured by Tosoh Corporation
+ Tosoh Corporation TSK-GEL SuperHZM-M x 4
Detector: RI (differential refractometer)
Data processing: Multi-station GPC-8020 model II manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow rate: 0.35 ml / min Standard: Monodispersed polystyrene Sample: Filtered 0.2% by mass tetrahydrofuran solution in terms of resin solids with a microfilter (100 μl)

  The iodine value is a value measured by the Wiis method.

Synthesis Example 1 <Synthesis of acrylic acrylate (1)>
A reactor equipped with a stirrer, a cooling tube, a dropping funnel and a nitrogen introducing tube was charged with 60 parts by weight of propylene glycol monomethyl ether, and the system temperature was raised to 100 ° C. while stirring. Next, 80 parts by mass of glycidyl methacrylate, 0.02 parts by mass of ethyl acrylate, 19.98 parts by mass of methyl methacrylate, and t-butylperoxy-2-ethylhexanoate (“Perbutyl O” manufactured by NOF Corporation) 2 A mixed solution consisting of parts by mass was added dropwise over 4 hours. After the dropping, the mixture was kept at the same temperature for 10 hours to obtain an epoxy group-containing acrylic polymer solution. The acrylic polymer solution had a nonvolatile content of 65.0% by mass and an epoxy equivalent of 285 g / eq (solid content).

  Next, in a reactor equipped with a stirrer, a cooling tube, a dropping funnel, and an air introduction tube, 66.2 parts by mass of acrylic polymer solution (solid content 43 parts by mass), 18 parts by mass of acrylic acid, and methoquinone 0 .05 parts, 1.2 parts by weight of triphenylphosphine, and 100 parts by weight of propylene glycol monomethyl ether were added, the temperature was raised to 105 ° C. while bubbling air into the reaction solution, and the reaction was continued for 10 hours to give a nonvolatile content of 45 An organic solvent solution of mass% acrylic acrylate resin was obtained.

Examples 1 to 4 and Comparative Example 1
Each component was blended according to the blending shown in Table 2 below, and finally ethyl acetate was added to adjust the solid content concentration to 30% by mass to obtain a one-pack type easy-to-adhesive. In addition, the compounding quantity in Table 2 is a solid content basis. Next, various evaluations were performed using the obtained one-pack type easy-to-adhesive. In addition, the comparative example 2 is the result of having performed various evaluation, without using an easily bonding agent.

[Creation of laminated film for evaluation]
A laminated sheet serving as a base material for bonding a polyethylene terephthalate film having a thickness of 125 μm (“X10-S” manufactured by Toray Industries, Inc.) and a polyvinylidene fluoride film having a thickness of 30 μm (“PVDF” manufactured by Arkema Co., Ltd.) using a urethane-based adhesive. Obtained.
The one-pack type easy-to-adhesives obtained in each Example and Comparative Example were applied to the polyvinylidene fluoride film side of the laminated sheet so that the coating amount after drying was ² to 3 g / m ^2, and 120 ° C. And dried for 30 seconds to form an adhesive layer. For Example 4 and Comparative Example 1 in which a polyisocyanate component was blended, aging was further performed at 40 ° C. for 3 days to obtain an adhesive laminated sheet having an easy-adhesion layer.

  The obtained adhesive laminate sheet having an easy-adhesion layer was cut into a width of 80 mm and a length of 200 mm to obtain an evaluation adhesive laminate sheet.

  Prepare one sheet of EVA sheet cut to a width of 80 mm and a length of 70 mm. The EVA sheet is laminated with two adhesive laminate sheets for evaluation so that the easy-adhesion layer is in contact with the EVA sheet. Using a laminator device, the laminate was evacuated to about 133 Pa at 150 ° C. for 5 minutes, and then pressed at 150 ° C. for 15 minutes at a pressure of 0.1 MPa to obtain a laminate for evaluation.

  Using the sample obtained by cutting the obtained laminate for evaluation into a width of 10 mm, initial adhesive strength and wet heat resistance were evaluated. The results are shown in Table 2.

[Initial adhesive strength evaluation method]
The laminate for evaluation was subjected to a 180 ° peel test at a crosshead speed of 100 mm / min with the unadhered portion sandwiched between upper and lower clips of a tensile tester (manufactured by A & D Co., Ltd.). The obtained measurement values were evaluated as follows.

A: 100 N / 10 mm or more B: 50 N / 10 mm or more to less than 100 N / 10 mm Δ: 15 N / 10 mm or more to less than 50 N / 10 mm X: Less than 15 N / 10 mm [Hygrothermal resistance evaluation method]
The laminate for adhesive strength evaluation was subjected to a pressure cooker test (PCT) for 24 to 48 hours (test conditions: 121 ° C. and relative humidity 100%), and the peel strength after the wet heat resistance test was measured under the same conditions as described above. did.
[Blocking resistance evaluation method]
A one-component type easy-adhesive is applied onto a fluororesin film (base film) so that the coating amount after drying is ² to 3 g / m ² and dried at 100 ° C. for 30 seconds to form a coating agent layer. did. Superimposed on the other of the fluororesin film (blank film), applying a load 5kg / cm ^2, 40 ℃, the set-off state of the blank film was allowed to stand for 72 hours was evaluated by the following criteria.
○: No trace on substrate film
Δ: There is a trace on the base film, and there is no settling on the blank film
×: There is a setback on the blank film

Abbreviations in Table 2 are as follows.
Acrylic polyol: Copolymer of methyl methacrylate / ethyl acrylate / hydroxyethyl methacrylate / hydroxyethyl acrylate / methacrylic acid, hydroxyl value 40 mg KOH / g (solid content), Tg 70 ° C., weight average molecular weight (Mw) 36,000)
M-402: Dipentaerythritol penta and hexaacrylate (“Aronix M-402” manufactured by Toagosei Co., Ltd.)
860-80SE: bisphenol A type epoxy resin (DIC Corporation "Epiclon 860-80SE" epoxy equivalent 250 g / eq. Ethyl acetate cut product, solid content 80 mass%)
EX-321: a mixture of diglycidyl ether and triglycidyl ether of trimethylolpropane (“Denacol EX-321” epoxy equivalent 140 g / eq. Manufactured by Nagase ChemteX Corporation)
N-3300: Isocyanurate of 1,6-hexamethylene diisocyanate (“Sumidur N-3300” isocyanate group (NCO) content 21.8% by mass, viscosity 2500 mPa · s / 25 ° C., manufactured by Sumika Bayer Urethane Co., Ltd.) )

A: Solar cell B: Surface protective substrate C: Interconnector D: Sealing material E: Back sheet F: Terminal a: Substrate sheet b: Curing of the one-pack type easy-adhesive for solar cell protective sheet of the present invention Adhesive layer

Claims (10)

  One-pack type for solar cell protective sheet comprising (meth) acryloyl group (meth) acrylic polymer (A) having an (meth) acryloyl group and an organic solvent (B) having an iodine value of 70 to 130 g / 100 g. Easy adhesive.   The (meth) acrylic polymer (A) comprises a glycidyl (meth) acrylate (a1) and an alkyl (meth) acrylate (a2) in a molar ratio [(a1) / (a2)] of 90/10 to 60. A compound having a carboxyl group and a (meth) acryloyl group or its anhydride is copolymerized with a (meth) acrylic resin copolymerized at a ratio of / 40, and the equivalent ratio [epoxy group / acid group] is 1/1 to 1 / The one-component easy-adhesive for a solar cell protective sheet according to claim 1, which is reacted at a ratio of 1.5. Solid content concentration is the range of 20-40 mass%, The 1 liquid type adhesive agent for solar cell protection sheets as described in any one of Claim 1 or 2 . The addition to the components (A) and the component (B), further one-easy adhesive for solar cell protective sheet according to any one of claims 1 to 3 comprising an epoxy compound (C). A fluororesin layer on the surface of the substrate sheet having a surface layer, applying a one-easy adhesive for solar cell back sheet according to any one of claims 1 to 4, then dried comprising a solar cell Protective sheet. It was subjected to corona treatment on the surface layer, the solar cell protective sheet for coating a one-easy adhesive, dried and made to claim 5 solar cell protective sheet according. The base sheet is, on both surfaces or one surface of the polyester base sheet, a solar cell protective sheet according to any one of the claims 5 or 6 fluorine resin layer is a laminated sheet formed. The solar cell protective sheet according to any one of claims 5 to 7, wherein a coating amount of the one-pack type easy-adhesive for the solar cell protective sheet is in a range of 1 to ²⁰ g / m2.   The solar cell protective sheet according to claim 8, wherein the total thickness is in the range of 80 to 300 μm. Solar cells, the surface protecting substrate, solar cell sealing materials, and to a solar cell protective sheet as an essential component, the solar cell protective sheet, base sheet of the surface layer on with a fluorine resin layer on the surface layer to, applying a one-easy adhesive for solar cell protective sheet according to any one of claims 1 to 4, and then are those having an easy adhesion layer formed by drying, and the adhesive layer is The solar cell protection sheet is disposed so as to be in contact with the solar cell sealing material.

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