JP5820068B2 - Easy-adhesive substrate and method for producing the same, protective sheet for solar cell including the easily-adhesive substrate, method for producing the same, and solar cell module - Google Patents

Description

  The present invention relates to an easy-adhesive substrate and a method for producing the same, a protective sheet for solar cells comprising such an easy-adhesive substrate and used as a surface protective sheet or a back surface protective sheet for a solar cell module, and a method for producing the same, and The present invention relates to a solar cell module using such a solar cell protective sheet.

  Solar cell modules that convert solar light energy into electrical energy are attracting attention as a clean energy source that can generate electricity without emitting carbon dioxide in response to environmental problems such as air pollution and global warming.

  In general, a solar cell module is made of a crystalline silicon, amorphous silicon, or the like that performs photoelectric conversion, a sealing material that includes an electrical insulator that seals the solar cell, and a surface (light-receiving surface) of the sealing material. It is comprised from the surface protection sheet (front sheet) laminated | stacked on the side, and the back surface protection sheet (back sheet) laminated | stacked on the back surface side of the sealing material. In order to provide the solar module with the weather resistance and durability that can withstand long-term use outdoors and indoors, the solar cells and sealing material are protected from wind, rain, moisture, dust, mechanical shock, etc. It is necessary to keep the inside of the battery module sealed from the outside air. For this reason, the protection sheet for solar cells is required to have moisture resistance and weather resistance that can withstand long-term use.

  In a general solar cell module, from the viewpoint of excellent balance between performance and cost, the main constituent material (main material) of the sealing material is a polyolefin resin, and the main material of the solar cell protective sheet is polyethylene terephthalate (PET). In some cases, polyester resins such as polyethylene naphthalate (PEN) are used. In this case, it may be required to adhere the polyolefin resin and the polyester resin, but these resins tend to be difficult to adhere because of different resin types.

  For this reason, an easy-adhesion coat layer is formed on the surface of the sealing material side of the base material mainly composed of polyester resin in the protective sheet for solar cell, and is adhered to the sealing material mainly composed of polyolefin resin. Sometimes it is done to improve the sex.

  For example, Patent Document 1 discloses a sheet for sealing a back surface of a solar cell, which includes an easy-adhesion coat layer formed from a coating composition comprising a specific ionomer-type polyurethane resin, a crosslinking agent, and polyacrylic acid or a derivative thereof. Yes.

  Moreover, in patent document 2, the adhesive layer formed from the urethane type adhesive agent on the surface at the side of the sealing material of a base polyester film, and ethylene-vinyl acetate copolymer (EVA) on the adhesive layer, and A solar cell back surface sealing sheet including a compatible resin layer formed of a compatible resin is disclosed.

  Further, Patent Document 3 discloses a solar cell polyester film containing an organosilane compound on at least one side. Patent Document 4 includes (i) one or more electronically interconnected solar cells, a solar cell layer having a light receiving side and a back side, and (ii) poly (vinyl butyral). Disclosed is a solar cell laminate comprising one sublayer and at least one preformed bilayer sheet comprising a second sublayer comprising a metal or polymer film.

JP 2009-81394 A International Publication No. 08/069024 JP 2011-77533 A Special table 2010-512027

  These documents are based on the premise that EVA is used as a main material constituting the sealing material, as is remarkable in the technology disclosed in Patent Document 2. However, from the viewpoint of productivity and quality, the main material of the sealing material may be replaced with a material other than EVA, such as ethylene- (meth) acrylate copolymer, polyvinyl butyral, silicone, and the like. There is. When such replacement is performed, it is unclear whether or not the easy-adhesion coat layer as disclosed in Patent Documents 1 to 3 can exhibit a desired function. In addition, in this specification, (meth) acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms.

  In view of the current situation, the present invention includes an easy-adhesive base material including an easy-adhesive coating layer that includes various types of thermoplastic materials and is excellent in adhesiveness to a layer having thermoplasticity as a whole, and such an easy-adhesive base material. It is an object to provide a manufacturing method. Moreover, this invention also makes it a subject to provide the protection sheet for solar cells provided with such a base material, and its manufacturing method. Furthermore, this invention also makes it a subject to provide a solar cell module provided with such a protection sheet for solar cells.

  The present invention provided to achieve the above object is, firstly, an easy-adhesive base material comprising a base material and an easy-adhesion coat layer laminated on at least one surface of the base material, The easy-adhesion coat layer is formed from a coating solution containing polyvinyl butyral having a softening point of 150 ° C. or less and a crosslinking agent, and the cross-linking structure of the polyvinyl butyral and the cross-linking agent has the easy-adhesion coat layer. Is an easy-adhesive substrate characterized by having (Invention 1).

  When polyvinyl butyral according to the easy-adhesion coat layer has the above-mentioned characteristics, when thermocompression bonding is performed to produce a solar cell module using the solar cell protective sheet provided with the easy-adhesive substrate according to the present invention. , An easy-adhesion coat layer, and a member or a component that contacts the easy-adhesion coat layer such as a sealing material (in this specification, a member and a component that touches the easy-adhesion coat layer such as a sealing material May be generically referred to as “)”. Moreover, since the easy-adhesion coat layer has a cross-linked structure, cohesive failure hardly occurs. Therefore, the solar cell protective sheet incorporated in the solar cell module is difficult to peel off from the sealing material.

  In the above invention (Invention 1), the content of the crosslinking agent contained in the coating liquid is such that the crosslinking reactive group of the crosslinking agent is equivalent to 1 equivalent of the amount of active hydrogen contained in the coating liquid. The amount of the active hydrogen is preferably 0.1 equivalent or more and 1.5 equivalent or less, and the active hydrogen preferably contains active hydrogen which the hydroxyl group of the polyvinyl butyral has (Invention 2). In this case, the function of the easy-adhesion coat layer that reduces the possibility that the base material is peeled off from the sealing material or the like is appropriately exhibited, and the easy-adhesive base material has excellent blocking resistance. It is easy to achieve both.

  In the said invention (invention 1 or 2), it is preferable that the butyralization degree of the polyvinyl butyral in the said easily bonding coating layer is 75 mol% or less (invention 3). When the degree of butyralization is in the above range, it becomes easy for the easy adhesion coat layer to have a crosslinked structure of polyvinyl butyral and a crosslinking agent.

  In the said invention (invention 1 to 3), it is preferable that the said crosslinking agent contains an isocyanate type crosslinking agent (invention 4).

  In the said invention (invention 1 to 4), it is preferable that the thickness of the said easily-adhesive coating layer is 0.01 micrometer or more and 2.0 micrometers or less (invention 5). In this case, it becomes easy to make it compatible that the function of the easy-adhesion coat layer is appropriately exhibited and the easy-adhesive substrate has excellent blocking resistance.

  In the said invention (invention 1-5), it is preferable that the said base material consists of a film containing a polyester-type resin (invention 6). It becomes easy to obtain a substrate having excellent hydrolysis resistance stably and inexpensively.

  In the said invention (invention 1-6), it is preferable that the said coating liquid further contains the 1 type, or 2 or more types of component chosen from the group which consists of the monomer and oligomer which have group which has an ethylenically unsaturated bond ( Invention 7).

  In the said invention (invention 7), it is preferable that the said component further has group which has active hydrogen (invention 8).

  2ndly, this invention is a manufacturing method of an easily-adhesive base material provided with a base material and the easily-adhesive coating layer laminated | stacked on the at least one surface of the said base material, Comprising: A softening point is 150 degrees C or less. A coating liquid containing polyvinyl butyral and a crosslinking agent is applied to one surface of the base material to form a coating liquid layer, and the coating liquid layer is dried to form an easy adhesion coating layer on the base material. The manufacturing method of the easily-adhesive base material characterized by doing is provided (invention 9).

  By implementing the manufacturing method using this coating liquid, the easily-adhesive base material which concerns on the said invention (invention 1 to 8) can be obtained easily and with high productivity.

  In the above invention (Invention 9), the content of the crosslinking agent contained in the coating liquid is such that the crosslinking reactive group of the crosslinking agent is equivalent to 1 equivalent of the amount of active hydrogen contained in the coating liquid. The amount of the active hydrogen is preferably 0.1 equivalent or more and 1.5 equivalent or less, and the active hydrogen preferably contains active hydrogen contained in the hydroxyl group of the polyvinyl butyral (Invention 10). In this case, it becomes easy to make the easy-adhesion coat layer of the obtained easy-adhesive substrate have a crosslinked structure at an appropriate density.

  In the said invention (invention 9 or 10), it is preferable that the butyralization degree of the polyvinyl butyral contained in the said coating liquid is 75 mol% or less (invention 11). When the degree of butyralization is in the above range, it becomes easy for the easy adhesion coat layer to have a crosslinked structure of polyvinyl butyral and a crosslinking agent.

  In the said invention (invention 9 to 11), it is preferable that the said crosslinking agent contains an isocyanate type crosslinking agent (invention 12).

  In the above inventions (Inventions 9 to 12), the coating solution preferably further contains one or more components selected from the group consisting of monomers and oligomers containing a group having an ethylenically unsaturated bond. (Invention 13).

  In the said invention (invention 13), it is preferable that the said component further has group which has active hydrogen (invention 14).

  3rdly, this invention is a protection sheet for solar cells provided with the easily-adhesive base material which concerns on the said invention (invention 1-8), Comprising: The surface on the opposite side to the said base material in the said easily-adhesive coating layer is sealed. Provided is a protective sheet for a solar cell that is a surface for contacting a stopper (Invention 15).

  In such a solar cell protective sheet, since the surface of the easy-adhesion coat layer serves as an adhesive surface with the sealing material, in the solar cell module in which the solar cell protective sheet is incorporated, the substrate of the solar cell protective sheet is sealed. The possibility of peeling from the stop material is reduced.

  Fourthly, the present invention provides an easy-adhesive base material according to the invention described above (Inventions 1 to 8), and a sealing material adhesive layer laminated on the surface of the easy-adhesive base material on the easy-adhesive coat layer side. The surface on the opposite side to the said easily bonding coat layer in the said sealing material contact bonding layer is a surface for contact | connecting a sealing material, The solar cell protective sheet characterized by the above-mentioned is provided (invention 16).

  In such a solar cell protective sheet, since the easy-adhesion coat layer is disposed between the sealing material adhesive layer and the base material, the possibility that the sealing material adhesive layer and the base material peel off is reduced. Therefore, in the solar cell module in which such a solar cell protective sheet is incorporated, the problem that the base material of the solar cell protective sheet peels off from the sealing material hardly occurs.

  In the said invention (invention 16), it is preferable that the said sealing material contact bonding layer contains polyvinyl butyral (invention 17). When the sealing material adhesive layer contains the same type of material as the easy-adhesion coat layer, these delaminations are less likely to occur.

  In the above invention (Invention 16 or 17), the sealing material adhesive layer preferably has a multilayer structure (Invention 18). In this case, the difference in thermal expansion coefficient between the sealing material and the substrate can be eliminated in a stepwise manner in the multilayer structure of the sealing material adhesive layer. The possibility of the substrate peeling off from the encapsulant is further reduced.

  5thly this invention is a manufacturing method of the protection sheet for solar cells which concerns on the said invention (invention 16 or 17), Comprising: The thermoplastic material for forming the said sealing material contact bonding layer is more than the softening point. Heating, supplying the heated thermoplastic material to the surface of the easy-adhesive substrate on the side of the easy-adhesive coating layer, cooling the thermoplastic material on the easy-adhesive substrate, and sealing the sealing material A manufacturing method characterized by forming an adhesive layer is provided (Invention 19).

  According to this manufacturing method, the adhesion between the easy-adhesion coat layer and the sealing material adhesive layer can be further improved. In some cases, the crosslinking reaction in the easy-adhesion coat layer can be advanced by heat from the thermoplastic material for forming the sealing material adhesive layer.

  6thly this invention is a manufacturing method of the protection sheet for solar cells which concerns on the said invention (invention 18), Comprising: Plural for forming the several layer which comprises the sealing material contact bonding layer provided with the said multilayer structure Each of the thermoplastic materials is heated above the softening point, and the heated thermoplastic materials are simultaneously or sequentially supplied to the surface of the easy-adhesive substrate on the side of the easy-adhesive coat layer, and the easy-adhesion A manufacturing method is provided, wherein the plurality of thermoplastic materials on a porous substrate are cooled simultaneously or individually to form a sealing material adhesive layer having the multilayer structure (Invention 20).

  According to this manufacturing method, the adhesiveness between the easy-adhesion coat layer and the sealing material adhesive layer can be further increased, and the adhesiveness between a plurality of layers constituting the sealing material adhesive layer can be further improved. it can. In some cases, the crosslinking reaction in the easy-adhesion coat layer can be advanced by heat from the thermoplastic material for forming the sealing material adhesive layer.

  In the said invention (invention 19 or 20), it is preferable that the said heat sealing material contact bonding layer is formed by the extrusion coating on the said easily-adhesive base material of the said thermoplastic material (invention 21). Such a manufacturing method is excellent in productivity.

  Seventh, the present invention is a solar cell module comprising a solar cell, a sealing material that encloses the solar cell, and two protective members stacked on each of the main surfaces of the sealing material, At least one of the protective members is provided with a solar cell protective sheet according to the invention (Inventions 15 to 18) (Invention 22).

  In such a solar cell module, since the possibility that the protective sheet for solar cell is peeled off from the sealing material is reduced, the quality is hardly deteriorated even when used for a long time.

  In the said invention (invention 22), it is preferable that the said sealing material contains polyvinyl butyral (invention 23). In this case, the element in contact with the sealing material in the solar cell protective sheet and the sealing material can contain the same type of material. At this time, the solar cell protective sheet is peeled off from the sealing material. The possibility of doing so is particularly reduced.

  The easy-adhesive substrate according to the present invention is excellent in adhesiveness to a layer made of a thermoplastic resin other than EVA such as polyvinyl butyral (PVB). Therefore, the solar cell protective sheet provided with such an easy-adhesive substrate is less likely to peel off the encapsulant and the sheet even when the encapsulant is mainly a thermoplastic resin other than EVA. The solar cell module comprising the solar cell protective sheet having the excellent moisture resistance and weather resistance, and the easy-adhesive substrate according to the present invention is less likely to deteriorate in quality even when used for a long period of time. There is expected.

It is a schematic sectional drawing of the easily-adhesive base material which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the protection sheet for solar cells which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the protection sheet for solar cells provided with the sealing material contact bonding layer based on other embodiment of this invention. It is a schematic sectional drawing of the protection sheet for solar cells provided with the fluororesin layer based on other embodiment of this invention. It is a schematic sectional drawing of the protection sheet for solar cells provided with a vapor deposition layer based on other embodiment of this invention. It is a schematic sectional drawing of the protection sheet for solar cells provided with the contact bonding layer and metal sheet based on other embodiment of this invention. It is a schematic sectional drawing of the solar cell module which concerns on one Embodiment of this invention. It is a schematic sectional drawing of the solar cell module which the front seat and back seat | sheet concerning other embodiment of this invention consist of the protection sheet for solar cells which concerns on this embodiment.

Hereinafter, embodiments of the present invention will be described.
1. As shown in FIG. 1, the easy-adhesive base material 1 according to this embodiment includes a base material 11 and an easy-adhesion coat layer 12 on one surface (upper surface in FIG. 1) of the base material 11. It has. The easy-adhesion coat layer 12 included in the easy-adhesive substrate 1 according to the present invention is excellent in adhesiveness with a thermoplastic sealing material.

(1) Base Material The base material 11 has only to be electrically insulative and can be laminated with the easy-adhesion coat layer 12, and usually a resin film is mainly used.

  As a resin film used for the base material 11, what is generally used as the resin film in the solar cell module backsheet is selected. Examples of such a resin film include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyamide resins such as nylon (trade name); A resin film such as a resin, a polystyrene resin, a polyacrylonitrile resin, a polyvinyl chloride resin, a polyvinyl acetal resin, a polyphenylene sulfide resin, or a polyphenylene ether resin is used.

  It is known that a polyethylene terephthalate (PET) film, which is a kind of the above-mentioned resin film, improves the hydrolysis resistance of the film when the oligomer content in the film is small. Examples of such PET films having excellent hydrolysis resistance include Lumirror (registered trademark) X10S (manufactured by Toray Industries, Inc.) and Melinex (registered trademark) 238 (manufactured by Teijin DuPont Films).

  In addition, the said resin film may contain various additives, such as a pigment, a ultraviolet absorber, a ultraviolet stabilizer, a flame retardant, a plasticizer, an antistatic agent, a lubricant, and an antiblocking agent, as needed. Examples of the pigment include titanium dioxide and carbon black. Examples of the ultraviolet absorber include benzophenone, benzotriazole, oxalic anilide, cyanoacrylate, and triazine.

  Here, when using the protective sheet for solar cells including the easy-adhesive substrate 1 according to the present embodiment as the back surface protective sheet of the solar cell module, the resin film contains a pigment that reflects visible light. Is preferred. Moreover, when using the protective sheet for solar cells provided with the easily adhesive base material 1 which concerns on this embodiment as a surface protective sheet of a solar cell module, it does not contain the pigment which reduces the transmittance | permeability of the light of visible region. It is preferable to contain an ultraviolet absorber for the purpose of improving the weather resistance.

  In the case where the base material 11 is composed of a resin film, the surface of the resin film on the side where the easy-adhesion coat layer 12 is laminated is to improve the adhesion between the easy-adhesion coat layer 12 and the base material 11. It is preferable to perform surface treatment (easy adhesion treatment) such as corona treatment or plasma treatment. Among these surface treatments, corona treatment is particularly preferable from the viewpoints of easy treatment and less damage to the substrate 11.

  The thickness of the base material 11 is appropriately set based on electrical insulation required for the solar cell module. For example, when the substrate 11 is a resin film, the thickness is preferably 10 μm or more and 300 μm or less. More specifically, when the substrate 11 is a PET film, the thickness is preferably 30 μm or more and 250 μm or less, and 40 μm or more and 200 μm or less from the viewpoint of electrical insulation and weight reduction. It is more preferable that it is 50 μm or more and 150 μm or less.

(2) Easy-adhesion coat layer The easy-adhesion base material 1 which concerns on this embodiment is equipped with the easy-adhesion coat layer 12 on the one surface of the base material 11, Preferably the surface where the above surface treatments were given. . The easy-adhesion coat layer 12 is formed from a coating liquid containing polyvinyl butyral having a softening point of 150 ° C. or less and a crosslinking agent, and has a crosslinked structure of the polyvinyl butyral and the crosslinking agent.

(I) Polyvinyl butyral Polyvinyl butyral (PVB) is a resin in which the hydroxyl group of polyvinyl alcohol (PVA) reacts with butyraldehyde. It is technically difficult to convert all the hydroxyl groups of PVA into a butyral, and since saponification of polyvinyl acetate is not completely performed in the production process of PVA, the amount of total hydroxyl groups that PVA can have However, the degree of butyralization, which is the ratio of the amount of butyralized hydroxyl group, is less than 80 mol%. The degree of butyralization (mol%) is obtained by calculating vinyl alcohol content (mass%) and vinyl acetate content (mass%) according to ASTM 1396-92, converting the unit to mol%, and subtracting from 100 mol%.

  The property of PVB can be controlled by adjusting the degree of butyralization. The degree of butyralization of PVB according to the easy-adhesion coat layer 12 of this embodiment is preferably 75 mol% or less. When the degree of butyralization exceeds 75 mol%, PVB has a small amount of hydroxyl group, and depending on the type of crosslinking agent described later, there is a concern that the reactivity between the crosslinking agent and the hydroxyl group may be reduced. When this reactivity decreases, the density of the crosslinked structure in the easy-adhesion coat layer 12 decreases, the strength of the easy-adhesion coat layer 12 decreases, and the adhesion of the easy-adhesive substrate 1 to the sealing material decreases. There is a case. In addition, depending on the type of material constituting the sealing material in contact with the easy-adhesive substrate 1, chemical bonding (hydrogen bonding or the like) between the sealing material and PVB is less likely to occur. The adhesive force between the coat layer 12 and the sealing material may be reduced.

  The lower limit of the degree of butyralization of PVB related to the easy-adhesion coat layer 12 of the present embodiment is not particularly limited, but when it is excessively low, the solubility of PVB in the coating liquid for forming the easy-adhesion coat layer 12 is lowered. Thus, there is a concern that the controllability of the thickness of the easy-adhesion coat layer 12 is lowered. When the thickness of the easy-adhesion coat layer 12 varies, the function of the easy-adhesion coat layer 12 (making the base material 11 and the sealing material difficult to peel off) may decrease. From the viewpoint of stably avoiding such problems, the degree of butyralization of PVB is preferably 40 mol% or more, and more preferably 60 mol% or more.

  The softening point of PVB according to the easy-adhesion coat layer 12 of this embodiment is 150 ° C. or less. The softening point of PVB can be controlled by its molecular weight. When the softening point is 150 ° C. or lower, it becomes easy to improve the adhesiveness by thermal fusion with the sealing material in contact with the easy-adhesion coat layer 12. Moreover, when the softening point of PVB is high, the solubility with respect to a solvent may become low, and at this time, the controllability of the thickness of the easy-adhesion coat layer 12 falls. From the viewpoint of further improving the adhesiveness with the above-described sealing material, the softening point of PVB is preferably 150 ° C. or lower, and more preferably 120 ° C. or lower. The lower limit of the softening point of PVB is not particularly limited, but when it is too low, the easy-adhesion coat layer 12 becomes excessively soft and blocking may occur when winding the easy-adhesive substrate 1. From the viewpoint of stably avoiding such problems, the softening point of PVB is preferably 90 ° C. or higher.

  In addition, said softening point is a flow start temperature measured using Shimadzu Corporation capillary rheometer (device name: CFT-500D) based on the reference test of JISK7210: 1995.

(Ii) Crosslinking agent The kind of the crosslinking agent contained in the coating liquid for forming the easy-adhesion coat layer 12 of this embodiment is not particularly limited as long as it can react with the hydroxyl group contained in PVB. In this specification, hydrogen having a functional group capable of reacting with a crosslinking agent, such as hydrogen having a hydroxyl group, is also referred to as “active hydrogen”. Specific examples of active hydrogen other than hydrogen having a hydroxyl group include hydrogen possessed by an amino group and hydrogen possessed by a carboxyl group.

  Examples of the crosslinking agent include dialdehydes such as glyoxal; polymer aldehydes such as dialdehyde starch; N-methylol compounds such as N-methylol urea and N-methylol melamine; dicarboxylic acids such as oxalic acid and maleic acid; Polycarboxylic acids such as polyacrylic acid, methyl vinyl ether-maleic acid copolymer, isobutylene-maleic anhydride copolymer; epoxy crosslinking agent; isocyanate crosslinking agent such as diisocyanate compound; polyvalent metal compound such as ammonium zirconium carbonate However, it is not limited to this.

  Specific examples of such a crosslinking agent include isocyanate-based crosslinking agents containing a polyisocyanate compound. The polyisocyanate compound is a compound having two or more isocyanate groups per molecule. Specific examples thereof include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 1, Aromatic polyisocyanates such as 4-diphenylmethane diisocyanate, xylylene diisocyanate, tetramethylxylene diisocyanate, tolidine isocyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate; dicyclohexylmethane-4,4′-diisocyanate, bicycloheptane triisocyanate , Cyclopentylene diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, xylylene diisocyanate Alicyclic isocyanate compounds and the like; hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and aliphatic isocyanates such as lysine diisocyanate. In addition, biuret, isocyanurate, urethane-modified products of these compounds, and reaction products of these compounds with non-aromatic low molecular active hydrogen-containing compounds such as ethylene glycol, trimethylolpropane, castor oil, etc. Modified bodies such as certain adduct bodies can also be used as a crosslinking agent.

  From the viewpoint of reactivity with active hydrogen such as hydrogen contained in the hydroxyl group contained in PVB, the polyisocyanate compound according to the easy-adhesion coat layer 12 of this embodiment preferably contains a xylylene diisocyanate compound, and xylylene diisocyanate. The trimethylolpropane adduct is particularly preferred.

  The crosslinking agent for forming the crosslinked structure of the easy-adhesion coat layer 12 in the present embodiment may be used alone or in combination of a plurality of types.

  The content of the crosslinking agent contained in the coating liquid for forming the easy-adhesion coat layer 12 is set to be 0.1. 0 with respect to 1 equivalent of the amount of active hydrogen contained in the coating liquid. The amount is preferably 1 equivalent or more and 1.5 equivalent or less. Hereinafter, the ratio (equivalent ratio) of the amount of the crosslinking reactive group contained in the coating solution to the amount of active hydrogen is also referred to as “CL / AH ratio”. When the active hydrogen contained in the coating liquid is derived from the hydroxyl group of PVB, the CL / AH ratio is the ratio (equivalent ratio) of the amount of crosslinking reactive groups in the crosslinking agent to the amount of hydroxyl groups in PVB. When the CL / AH ratio is excessively small, the content of the crosslinking agent is excessively decreased, and there is a concern that the existing density of the crosslinked structure in the easy-adhesion coat layer 12 is excessively decreased. When the density of the cross-linked structure is excessively low, the easy-adhesion coat layer 12 may be excessively soft and may not function properly. From the viewpoint of more stably exhibiting the function of the easy adhesion coat layer 12, the CL / AH ratio is preferably 0.2 or more, more preferably 0.5 or more, and 0.8 or more. It is particularly preferable to do this. On the other hand, when the CL / AH ratio is excessively large, a large amount of unreacted cross-linking agent remains in the easy-adhesion coat layer 12 even when the cross-linking reaction is advanced. This increases the possibility of blocking. From the viewpoint of avoiding these problems more stably, the CL / AH ratio is preferably 1.4 or less, more preferably 1.3 or less, and particularly preferably 1.2 or less.

  The existing density of the crosslinked structure of the easy-adhesion coat layer 12 of the present embodiment is not particularly limited. When the density is excessively high, the easy-adhesion coat layer 12 loses thermoplasticity and the adhesiveness with the sealing material is lowered. When the density is excessively low, the easy-adhesion coat layer 12 becomes excessively soft. Thus, it may be set as appropriate according to the characteristics required for the easy-adhesion coat layer 12 while taking into consideration that the adhesiveness to the sealing material is reduced or blocking is likely to occur.

(Iii) Other components The easy-adhesion coat layer 12 of this embodiment preferably contains a crosslinking accelerator from the viewpoint of accelerating the crosslinking reaction of the crosslinking agent. Specifically, the crosslinking accelerator which consists of a metal organic compound is mentioned. Here, the “metal organic compound” includes an organic metal compound having at least one metal-carbon bond and a metal organic compound having at least one metal-heteroatom bond. Specifically, for example, an organometallic compound such as dibutyltin dichloride, a fatty acid salt of an organometallic compound such as dimethyltin dilaurate, and a thioglycolic acid of an organometallic compound such as dimethyltin bis (octylthioglycolate) salt Metal salts such as ester salts and bismuth octylate are included in the concept of metal organic compounds. The metal soap refers to a metal salt other than an alkali metal salt of fatty acid (soap in a narrow sense).

  The metal contained in the metal organic compound is not particularly limited, but is preferably at least one selected from tin, zinc, lead, and bismuth. Examples of metal organic compounds containing tin include organic tin compounds such as dimethyltin dichloride; fatty acid salts of organic tin compounds such as dihexyltin diacetate and dioctyltin dilaurate; dimethyltin bis (isooctylthioglycolate) salt; Thioglycolic acid ester salts of organic tin compounds such as dimethyltin bis (isooctylthioglycolic acid ester) salt and dioctyltin bis (isooctylthioglycolic acid ester) salt; metal soap such as tin octylate and tin decanoate Is mentioned. Examples of the metal organic compound containing zinc include zinc 2-ethylhexylate and zinc naphthenate. Examples of the metal organic compound containing lead include lead stearate, lead 2-ethylhexylate, lead naphthenate and the like. Examples of the metal organic compound containing bismuth include bismuth 2-ethylhexylate and bismuth naphthenate. Among these organometallic compounds, those containing bismuth are preferable because of their excellent curing accelerating ability.

  Although content of a crosslinking accelerator is not specifically limited, 1 ppm or more and 5 mass% or less are preferable with respect to the easily bonding coating layer 12 whole, 10 ppm or more and 1 mass% or less are more preferable, and 50 ppm or more and 0.5 mass% or less are preferable. Particularly preferred.

  The coating liquid for forming the easy-adhesion coat layer 12 of the present embodiment contains one or more components selected from the group consisting of monomers and oligomers having a group having an ethylenically unsaturated bond. Also good. In the present specification, the above component is also referred to as “component (A)”.

  When the sealing material disposed so as to be in contact with the easy-adhesion coat layer 12 in use contains a component capable of reacting with the ethylenically unsaturated bond, the component (A) is a group having the ethylenically unsaturated bond. It can react with said component contained in a sealing material by. Therefore, the possibility of delamination between the easy-adhesion coat layer 12 and the sealing material is further reduced. As a result, it is not necessary to perform easy adhesion treatment such as corona treatment on the surface of the substrate 11 facing the easy adhesion coating layer, and production is facilitated (the number of steps is reduced). The above advantages can also be enjoyed. In addition, as a sealing material which has a component which can react with an ethylenically unsaturated bond, the case where a sealing material uses ethylene-vinyl acetate copolymer (EVA) as a main material is mentioned as a specific example.

  Examples of the group having an ethylenically unsaturated bond that component (A) has include a vinyl group, an allyl group, and a (meth) acryloyl group. Component (A) may have one or more groups having an ethylenically unsaturated bond. From the viewpoint of high reactivity, the component (A) preferably has a plurality of groups having an ethylenically unsaturated bond.

  As long as it has the above characteristics, the specific structure of the component (A) is not particularly limited. Taking the case where the group having an ethylenically unsaturated bond as the component (A) is a (meth) acryloyl group, as a specific example of the component (A), pentaerythritol tetra (meth) acrylate, 1,4- Butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, hydroxypivalate neopentyl glycol di (meth) acrylate, di Cyclopentanyl di (meth) acrylate, caprolactone-modified dicyclopentenyl di (meth) acrylate, ethylene oxide-modified phosphoric acid di (meth) acrylate, allylated cyclohexyl di (meth) acrylate, isocyanurate di (meth) acrylate, trimethylolpropane Tri (meta) Dipentaerythritol tri (meth) acrylate, propionic acid modified dipentaerythritol tri (meth) acrylate, pentaerythritol tri (meth) acrylate, propylene oxide modified trimethylolpropane tri (meth) acrylate, tris (acryloxyethyl) isocyanate Examples thereof include polyfunctional (meth) acrylates such as nurate, propionic acid-modified dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and caprolactone-modified dipentaerythritol hexa (meth) acrylate.

  Component (A) may further have a group having active hydrogen. Examples of the group having active hydrogen include a hydroxyl group, an amino group, and a carboxyl group. When the component (A) has a group having active hydrogen, the number of the group having active hydrogen in the component (A) may be one or plural. The active hydrogen of the component (A) is expected to interact physically and chemically with other components contained in the easy adhesion coat layer 12. Most typically, the case where the active hydrogen of component (A) reacts with the crosslinking reactive group of the crosslinking agent and is linked to PVB (chemical interaction) is exemplified. As an example other than this case, when a plurality of components (A) are linked via a crosslinking agent, or when active hydrogen of the component (A) forms a hydrogen bond with a hydroxyl group of PVB (chemical interaction) ), The case where the component (A) and the crosslinking agent and / or PVB are intertwined (physical interaction).

  When the component (A) has a group having active hydrogen, the aforementioned CL / AH ratio is calculated in consideration of the active hydrogen of the hydroxyl group of PVB and the active hydrogen of component (A).

  The specific structure of component (A) further having a group having active hydrogen is not particularly limited. Taking the case where the group having active hydrogen is a hydroxyl group as an example, as specific examples of the component (A), pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, propionic acid-modified dipentaerythritol tri ( Examples include meth) acrylate, 2-hydroxyethyl acrylate (HEA), 2-hydroxypropyl acrylate (HPA), and 4-hydroxybutyl acrylate (4-HBA).

  In addition to the above-mentioned components, the easy-adhesion coat layer 12 of the present embodiment includes coloring materials such as dyes and pigments, antioxidants such as anilides and phenols, ultraviolet absorbers such as benzophenone and benzotriazole, talc, You may contain filler components, such as titanium dioxide, a silica, and starch, a plasticizer, antioxidant, a light stabilizer, a dispersing agent, a leveling agent. Although content of these components is arbitrary, it is preferable that these components do not exceed 10 mass% with respect to the whole easy-adhesion coat layer 12 as a whole. When reducing the thickness of the easy-adhesion coat layer 12, it is preferable not to contain such components.

(Iv) Thickness of easy-adhesion coat layer The thickness of the easy-adhesion coat layer 12 of this embodiment is not particularly limited, but is preferably 0.001 μm or more and 2.0 μm or less. When the easy-adhesion coat layer 12 is excessively thin, there is a concern that the adhesiveness to the sealing material is reduced, and when it is excessively thick, the productivity is reduced or the blocking resistance is reduced. Concern about potential problems. From the viewpoint of more stably avoiding the deterioration of the adhesiveness to the sealing material and the occurrence of the above secondary problems, the preferred thickness of the easy-adhesion coat layer 12 is 0.01 μm or more and 1.5 μm or less, More preferably, it is 0.03 μm or more and 1.0 μm or less, and particularly preferably 0.05 μm or more and 0.3 μm or less.

2. The manufacturing method of the easily-adhesive base material The manufacturing method of the easily-adhesive base material 1 which concerns on this embodiment is not specifically limited. A preferred example is as follows. That is, a coating liquid containing PVB and a crosslinking agent is applied to one surface of the substrate 11 to form a coating liquid layer, and the coating liquid layer is dried and heated to form an easy-adhesion coating layer on the substrate 11. 12 is formed.

The above manufacturing method will be described in detail.
First, a coating liquid containing PVB and a crosslinking agent is prepared. The preparation method is arbitrary. For example, a coating liquid can be obtained by dissolving PVB, a crosslinking agent, and, if necessary, other components such as a crosslinking accelerator in an organic solvent. From the viewpoint of improving the controllability of the thickness of the resulting easy-adhesion coat layer 12, it is preferable to dissolve all soluble components.

  The preferred range of the degree of butyralization of PVB contained in the coating liquid is the same as the preferred range of the degree of butyralization of PVB in the resulting easy-adhesion coat layer 12, and is preferably 75 mol% or less.

  The kind of organic solvent used for preparing the coating liquid is not particularly limited. Alcohols such as methanol, ethanol, isopropyl alcohol (IPA) and n-butanol; ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK); and solvents having high polarity such as esters such as ethyl acetate may be used. Solvents with low polarity such as aromatic compounds such as toluene and xylene; aliphatic compounds such as cyclohexane and solvent naphtha may be used. The compound constituting the solvent may be one kind or plural kinds.

  When it is required to reduce the viscosity of the coating solution, for example, to make the easy-adhesion coat layer 12 into a thin film, it is preferable to use a solvent containing an alcohol solvent and an aromatic solvent. In this case, the volume ratio of the alcohol solvent and the aromatic solvent may be set as appropriate. Usually, this volume ratio is preferably in the range of 2: 8 to 6: 4, more preferably in the range of 3: 7 to 5: 5. On the other hand, when the thickness of the liquid layer made of the coating liquid is increased, for example, to make the easy adhesion coat layer 12 thick, the resulting easy adhesion coat layer 12 may be whitened. When this whitening becomes a problem, it is preferable to contain about 5% by volume of n-butanol with respect to the total volume of the solvent.

  What is necessary is just to set content of the crosslinking agent in said coating liquid in consideration of the preferable range of the above-mentioned CL / AH ratio. When said coating liquid contains a component (A), the content is not specifically limited. Usually, if it contains about 1 mass part or more with respect to 100 mass parts of PVB, the effect which contained the component (A) can be acquired. From the viewpoint of obtaining such effects more stably, the content of the component (A) in the coating liquid is preferably about 2 parts by mass or more, and 6 parts by mass or more with respect to 100 parts by mass of PVB. It is more preferable that the content be 8 parts by mass or more. When the content of the component (A) in the coating liquid is excessively large, the function of the easy-adhesive coat layer 12 tends to decrease due to the relative decrease in the content of PVB and the like. In general, it is preferably about 200 parts by mass or less, more preferably 150 parts by mass or less, and particularly preferably 100 parts by mass or less with respect to 100 parts by mass of PVB.

  The obtained coating liquid is applied on the base material 11, preferably on the surface of the base material 11 that has been subjected to a surface treatment such as corona treatment to form a coating liquid layer on the base material 11. This coating method is arbitrary, and examples thereof include a rod coater, a knife coater, a gravure coater, and a die coater.

  The coating liquid layer on the obtained substrate 11 is dried. The drying method is arbitrary. For example, the coating liquid layer may be dried together with the substrate 11 in an oven heated to about 100 ° C., or the solvent contained in the coating liquid layer is volatilized by setting the atmosphere as a reduced pressure environment. May be. Or you may leave the base material 11 in air | atmosphere, and may dry the coating liquid layer on it.

  Thus, the easy-adhesion coat layer 12 can be obtained by drying the coating liquid layer on the substrate 11. In this drying, the cross-linking reaction between PVB and the cross-linking agent may be sufficiently advanced, or a step for causing the cross-linking reaction to proceed may be provided after the drying. The conditions of this step are not limited, and it may be cured for about 7 to 14 days in a normal temperature environment of about 23 ° C., or may be put into a constant temperature bath of 40 to 60 ° C. for about 1 to 3 days to promote the crosslinking reaction. May be. The heating for causing the crosslinking reaction to proceed may be carried out as a single heating step, or the easy-adhesion coat layer 12 is formed by heating the easy-adhesion coat layer 12 during the implementation of other steps. May be. As a specific example thereof, a thermoplastic material for forming a sealing material adhesive layer (details will be described later) is supplied in a molten state on the easy-adhesion coat layer 12 formed on the substrate 11, For example, the easy-adhesion coat layer 12 is heated with a thermoplastic material to cause a crosslinking reaction in the easy-adhesion coat layer 12 to proceed.

3. Protective sheet for solar cell The protective sheet for solar cell according to the present embodiment includes the above-described easy-adhesive substrate 1. Hereinafter, a specific configuration of the solar cell protective sheet will be described with reference to the drawings.

  As shown in FIG. 2, the solar cell protective sheet 2 according to an example of the present embodiment includes the above-described easy-adhesive substrate 1, and the surface 12 a opposite to the substrate 11 in the easy-adhesion coat layer 12 is It is a surface (adhesion surface) for adhering with a sealing material. That is, in this example, the easy-adhesion coat layer 12 of the solar cell protective sheet 2 is for being directly adhered to the sealing material.

  As described above, the sealing material may be mainly made of a polyolefin-based resin. However, since the easy-adhesion coat layer 12 of the present embodiment contains a component based on PVB, the sealing material is mainly made of a polyolefin-based resin. Has heat-fusibility to the material. Depending on the type of polyolefin resin, the hydroxyl group and / or the crosslinking reactive group of the crosslinking agent in PVB can remain as they are, or even after forming a crosslinked structure, it can chemically interact with the polyolefin resin. In addition, due to such interaction, the easily-adhesive substrate 1 can be firmly bonded to the sealing material. In particular, when the encapsulant is mainly a polymer having a carbonyl group or a hydroxyl group such as EVA or PVB, such chemical interaction is likely to occur.

  As shown in FIG. 3, the solar cell protective sheet 3 according to another example of the present embodiment is provided on the surface of the above-mentioned easy-adhesive substrate 1 and the easy-adhesive substrate 1 on the easy-adhesive coat layer 12 side. A laminated sealing material adhesive layer 31 may be provided. At this time, the surface 31 a opposite to the easy-adhesion coat layer 12 in the sealing material adhesive layer 31 is a surface (adhesive surface) for adhering to the sealing material in the solar cell protective sheet 3. In the present specification, the “sealing material adhesive layer” is a layer that is closest to the sealing material when incorporated in the solar cell module in the solar cell protective sheet 3, and has an adhesive property to the sealing material. By providing the sealing material adhesive layer 31, the possibility that the solar cell protective sheet 3 is peeled off from the sealing material can be further reduced. In the solar cell protective sheet 3 having such a configuration, the easy-adhesion coat layer 12 is used to reduce the possibility that the base material 11 is peeled off from the sealing material. Therefore, a kind of so-called tie layer is used. It can be said.

  As described above, since the easy-adhesion coat layer 12 of the easy-adhesive substrate 1 has heat-fusibility and can cause chemical interaction due to the hydroxyl group of PVB, the easy-adhesive substrate 1 is sealed. The material adhesion layer 31 can be firmly adhered. In this case (that is, when the sealing material adhesive layer 31 is laminated on the surface of the easy adhesion coat layer 12 opposite to the base material 11), suitable ranges such as the composition and thickness of the easy adhesion coat layer 12 are shown in FIG. 2 is the same as in the case of the easy-adhesion coat layer 12 in the solar cell protective sheet 2 shown in FIG. 2 (that is, the surface of the easy-adhesion coat layer 12 opposite to the substrate 11 is a surface for contacting the sealing material). Therefore, the description is omitted.

  In the case of a configuration in which the solar cell module is configured to include a glass on the front surface side of the sealing material and a protective sheet having a resin-based member on the back surface side of the sealing material, when the module is subjected to a thermal cycle test, Since the thermal expansion coefficient of each component in the module is different from each other, a strong shearing force may be applied between the sealing material and the protective sheet. In such a case, when the protective sheet has a structure in which the base material and the sealing material adhesive layer are directly laminated, the shear stress in the vicinity of these interfaces in the entire solar cell module is relatively lowest, and this Destruction may occur in the area. However, when the protective sheet has a laminated structure of the easy-adhesive base material 1 and the sealing material adhesive layer 31 according to the present embodiment, the easy-adhesive base material 1 has the easy-adhesion coat layer 12. The possibility that the material 11 peels from the sealing material adhesive layer 31 is reduced.

  In the solar cell protective sheet 3 according to this example, the sealing material adhesive layer 31 may contain a material that can function as a sealing material. Specific examples of such materials include polyolefin resins such as EVA and PVB. When the sealing material adhesive layer 31 contains PVB, it is preferable because it has excellent adhesion to the easy-adhesion coat layer 12. As described above, since the easy-adhesion coat layer 12 of the easy-adhesive substrate 1 can be firmly adhered to the sealing material, when the sealing material adhesive layer 31 contains the above-mentioned material, the sealing material is sealed. Similarly to the case of the stopper, the easily adhesive substrate 1 can be firmly adhered to the sealing material adhesive layer 31 in the same manner. Therefore, the possibility that the base material 11 of the solar cell protective sheet 3 according to this example is peeled off from the sealing material is particularly reduced.

  In the solar cell protective sheet 3 according to this example, the sealing material adhesive layer 31 may have a multilayer structure. The specific configuration is arbitrary. For example, the layers constituting the multilayer structure have different thermal expansion coefficients, and the difference in thermal expansion coefficient between the sealing material and the base material 11 is sealed. You may make it eliminate in steps by the layer which comprises the material adhesion layer 31. FIG. In this case, the possibility that the base material 11 of the solar cell protective sheet 3 is peeled from the sealing material can be further reduced, which is preferable.

Here, the configuration of the sealing material adhesive layer 31 will be described in some detail.
The sealing material adhesive layer 31 has thermoplasticity as a whole, and its softening point is higher than the upper limit of the normal use temperature of the solar cell protective sheet, and the heat of the sealing material and the sealing material adhesive layer 31 is higher. Below the temperature normally applied for fusing. In many cases, the softening point of the sealing material adhesive layer 31 is usually set in the range of about 90 ° C to about 130 ° C.

As long as the above thermal characteristics are satisfied, the composition of the sealing material adhesive layer 31 is not particularly limited. A polyolefin-based resin is preferably used as the main material of the sealing material adhesive layer 31 because of the ease with which the above thermal characteristics are satisfied. Specific examples thereof include high-density polyethylene (HDPE, density: 942kg / ^{m 3} or more), medium density polyethylene (MDPE, density: 930 kg / ^{m 3} or more and less than 942kg / ^{m 3),} low density polyethylene (LDPE, density: 910 kg / ^{m 3} or more and less than 930 kg / ^{m 3),} very low density polyethylene (VLDPE, density: 870 kg / ^{m 3} or more, 910 kg / ^m less than ³⁾ such as a polyethylene resin, a polypropylene resin (PP), polyethylene - polypropylene polymer, Olefin-based elastomer (TPO), cycloolefin resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl acetate-maleic anhydride copolymer, ethylene- (meth) acrylic acid copolymer, ethylene- (meth) Acrylic ester copolymer, ethylene- (meth) acrylate Examples thereof include a rylate ester-maleic anhydride copolymer.

  In addition, resin which makes the main material of the sealing material contact bonding layer 31 may be comprised from one type, and may be comprised from multiple types. Further, the sealing material adhesive layer 31 may have a cross-linked structure, but the density of the cross-linked structure should be limited to a range satisfying the above thermal characteristics. The sealing material adhesive layer 31 may contain components other than the resin-based material forming the main material. Specific examples of the components are the same as those of the other components that may be contained in the substrate 11 described above, and are coloring materials such as dyes and pigments, antioxidants such as anilides and phenols, benzophenones, and benzotriazoles. UV absorbers such as those, filler components such as talc, titanium dioxide, silica, and starch, plasticizers, antioxidants, light stabilizers, dispersants, leveling agents and the like. Although content of these components is arbitrary, it is preferable that these components do not exceed 10 mass% with respect to the sealing material contact bonding layer 31 whole as a whole.

  As shown in FIG. 4, the solar cell protective sheet 2 or 3 according to the present embodiment has a surface on the side where the easy-adhesive coat layer 12 of the base material 11 of the easy-adhesive base material 11 is not laminated (the lower surface in FIG. 4). ) May be provided with a fluororesin layer 13. In addition, in FIG. 4, the case where the fluororesin layer 13 is provided in the protection sheet 2 for solar cells shown in FIG. 2 is shown as a specific example. By providing the fluororesin layer 13 in this manner, the weather resistance and chemical resistance of the solar cell protective sheet 2 are improved. In addition, when the base material 11 consists of a resin film, in order to improve the adhesiveness with the fluororesin layer 13, the surface of the side by which the fluororesin layer 13 of the said resin film is laminated | stacked has a corona treatment and a plasma treatment. It is preferable that surface treatment (easy adhesion treatment) such as primer treatment is performed.

  The fluororesin layer 13 is not particularly limited as long as it contains fluorine. For example, the fluororesin layer 13 is constituted by a sheet having a fluorine-containing resin (fluorine-containing resin sheet), a coating film formed by applying a paint containing the fluorine-containing resin, or the like. Is done. Among these, from the viewpoint of making the fluororesin layer 13 thinner in order to reduce the weight of the solar cell protective sheet 2, a coating film formed by applying a paint having a fluorine-containing resin is preferable.

  As the fluorine-containing resin sheet, for example, a sheet obtained by processing a resin mainly composed of polyvinyl fluoride (PVF), ethylene chlorotrifluoroethylene (ECTFE), or ethylene tetrafluoroethylene (ETFE) is used. Examples of the resin mainly composed of PVF include E.I. I. “Tedlar” (trade name) manufactured by du Pont de Nemours and Company. Examples of the resin mainly composed of ECTFE include “Halar” (trade name) manufactured by Solvay Solexis. Examples of the resin mainly composed of ETFE include “Fluon” (trade name) manufactured by Asahi Glass Co., Ltd.

  When the fluororesin layer 13 is a fluorine-containing resin sheet, the fluororesin layer 13 is laminated on the base material 11 via an adhesive layer. The layer having adhesiveness is composed of an adhesive having adhesiveness to the substrate 11 and the fluorine-containing resin sheet. Examples of such adhesives include acrylic adhesives, polyurethane adhesives, epoxy adhesives, polyester adhesives, and polyester polyurethane adhesives. These adhesives may be used individually by 1 type, and may be used in combination of 2 or more types.

  On the other hand, when the fluororesin layer 13 is a coating film formed by applying a paint having a fluorine-containing resin, usually, the paint containing the fluorine-containing resin is directly applied to the substrate 11 without using an adhesive layer. By doing so, the fluororesin layer 13 is laminated on the substrate 11.

  The paint containing the fluorine-containing resin is not particularly limited as long as it is dissolved in a solvent or dispersed in water and can be applied.

  The fluorine-containing resin contained in the paint is not particularly limited as long as it does not impair the effects of the present invention and contains fluorine. However, it is usually soluble in a paint solvent (organic solvent or water) and can be crosslinked. Things are used. As the fluorine-containing resin, it is preferable to use a fluoroolefin resin having a crosslinkable functional group. Examples of the crosslinkable functional group include a hydroxyl group, a carboxyl group, an amino group, and a glycidyl group. Examples of the fluoroolefin resin include chlorotrifluoroethylene, tetrafluoroethylene, hexafluoropropylene, and pentafluoropropylene.

  Specific examples of the fluoroolefin resin having a crosslinkable functional group include “LUMIFLON” (trade name) manufactured by Asahi Glass Co., Ltd., “CEFRAL COAT” (trade name) manufactured by Central Glass Co., Ltd. Name) and other polymers based on chlorotrifluoroethylene (CTFE) as a main component, and polymers based on tetrafluoroethylene (TFE) such as “ZEFFLE” (trade name) manufactured by Daikin Industries, Ltd. .

  The coating material may contain a crosslinking agent, a curing catalyst, a solvent and the like in addition to the fluorine-containing resin described above, and may further contain an inorganic compound such as a pigment and a filler, if necessary.

  The coating film of the fluorine-containing resin is preferably crosslinked with a crosslinking agent in order to improve weather resistance and scratch resistance. The crosslinking agent is not particularly limited as long as the effects of the present invention are not impaired, and metal chelates, silanes, isocyanates, or melamines are preferably used. Assuming that the solar cell protective sheet 2 is used outdoors for a long period of time, aliphatic isocyanates are preferable as the crosslinking agent from the viewpoint of weather resistance.

  As a method of applying the paint to the easily adhesive substrate 1 or the substrate 11, a known method is used. For example, the fluororesin layer 13 to be obtained is desired by a bar coating method, a die coating method, a gravure coating method, or the like. What is necessary is just to apply | coat so that it may become thickness.

  The drying temperature of the paint applied to the easy-adhesive substrate 1 or the substrate 11 may be any temperature that does not impair the effects of the present invention. From the viewpoint of reducing the influence on the easy-adhesive substrate 1 or the substrate 11. Is preferably in the range of 50 to 130 ° C.

  The thickness of the fluororesin layer 13 is set in consideration of weather resistance, chemical resistance, weight reduction, and the like, and is preferably 5 μm or more and 50 μm or less, and particularly preferably 10 μm or more and 30 μm or less.

  As shown in FIG. 5, the solar cell protective sheet 2 or 3 according to this embodiment is provided on the surface of the base 11 of the easy-adhesive base 1 on which the easy-adhesion coat layer 12 is not laminated, as shown in FIG. And a fluororesin layer 13 may be provided with a vapor deposition layer 14, or a metal sheet 16 may be laminated via an adhesive layer 15 as shown in FIG. The fluororesin layer 13 described above may be provided on the surface (the lower surface in FIGS. 5 and 6) of the sheet 16. 5 and 6 show an example in which the vapor deposition layer 14 and the like are provided on the solar cell protective sheet 2 shown in FIG. Thus, by providing the vapor deposition layer 14 or the metal sheet 16, the moisture-proof property and weather resistance of the protection sheet 2 for solar cells can be improved. In the present embodiment, the “metal sheet” means a sheet-like member made of a metal-based material (that is, a material containing a metal element).

  In addition, when the base material 11 consists of a resin film, in order to improve the adhesiveness with the vapor deposition layer 14 or the contact bonding layer 15, the surface by which the vapor deposition layer 14 or the contact bonding layer 15 of the said resin film is laminated | stacked is a corona. Surface treatment such as treatment, plasma treatment, and primer treatment is preferably performed.

  The vapor deposition layer 14 is comprised from inorganic materials, such as a metal or a semimetal, or an oxide, nitride, silicide, etc. of a metal or a semimetal, By comprising such a material, the easily-adhesive base material 1 (solar cell) The protective sheet 2) can be given moisture resistance (water vapor barrier property) and weather resistance.

  Examples of the vapor deposition method for forming the vapor deposition layer 14 include chemical vapor deposition such as plasma chemical vapor deposition, thermal chemical vapor deposition, and photochemical vapor deposition, or vacuum vapor deposition, sputtering, and ion plating. A physical vapor phase method such as a method is used. Among these methods, the sputtering method is preferable in consideration of operability and controllability of the layer thickness.

  Examples of the metal used as the raw material of the vapor deposition layer 14 include aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium rim (Na), titanium (Ti), and lead. (Pb), zirconium (Zr), yttrium (Y) and the like. Examples of the semimetal include silicon (Si) and boron (B). Examples of these metal or metalloid oxides, nitrides, and oxynitrides include aluminum oxide, tin oxide, silicon oxide, silicon nitride, silicon oxynitride, and aluminum oxynitride.

  The vapor deposition layer 14 may be made of one kind of inorganic material or may be made of a plurality of kinds of inorganic materials. When the vapor deposition layer 14 is made of a plurality of types of inorganic materials, it may be a vapor deposition layer having a laminated structure in which the layers made of the respective inorganic materials are sequentially vapor deposited, or may be a vapor deposition layer in which a plurality of types of inorganic materials are vapor deposited simultaneously. May be.

  The thickness of the vapor deposition layer 14 is appropriately set in consideration of the water vapor barrier property, and is changed depending on the type of inorganic material used, vapor deposition density, and the like. Usually, the thickness of the vapor deposition layer 14 is preferably 5 nm or more and 200 nm or less, and particularly preferably 10 nm or more and 100 nm or less.

  On the other hand, the metal sheet 16 can also impart moisture resistance (water vapor barrier property) and weather resistance to the solar cell protective sheet 2, similarly to the vapor deposition layer 14. The material of the metal sheet 16 is not particularly limited as long as it has such a function, and examples thereof include metals such as aluminum and aluminum alloys such as aluminum-iron alloys.

  The thickness of the metal sheet 16 is not particularly limited as long as the effects of the present invention are not impaired, but from the viewpoint of low pinhole occurrence frequency, high mechanical strength, high water vapor barrier properties, and weight reduction, etc. It is preferably 5 μm or more and 100 μm or less, and particularly preferably 10 μm or more and 50 μm or less.

  The adhesive layer 15 is composed of an adhesive having adhesiveness to the base material 11 and the metal sheet 16. As the adhesive constituting the adhesive layer 15, for example, an acrylic adhesive, a polyurethane adhesive, an epoxy adhesive, a polyester adhesive, a polyester polyurethane adhesive, or the like is used. These adhesives may be used individually by 1 type, and may be used in combination of 2 or more type.

  The thickness of the adhesive layer 15 is not particularly limited as long as the effects of the present invention are not impaired. Usually, the thickness is preferably 1 μm or more and 20 μm or less, and particularly preferably 3 μm or more and 10 μm or less.

  In addition, in the above embodiment, although the solar cell protective sheet 2 in which the easy-adhesion coat layer 12 was laminated on one surface of the base material 11 in the easy-adhesive base material 1 was illustrated, the solar cell protection according to the present invention. The sheet is not limited to this, and an easy-adhesion coat layer may be laminated on the other surface of the substrate 11 (the surface opposite to the one surface).

4). The manufacturing method of the protection sheet for solar cells The method to manufacture the protection sheet for solar cells which concerns on this embodiment is not specifically limited. If the easily adhesive base material 1 is manufactured, the solar cell protective sheet 2 shown in FIG. 2 becomes a solar cell protective sheet as it is. For the solar cell protective sheet 3 shown in FIG. 3, the easy-adhesive substrate 1 and the sealing material adhesive layer 31 constituting the protective sheet 3 are appropriately laminated using methods such as thermocompression bonding, coating / drying, and extrusion coating. That's fine. Hereinafter, as an example, a method for forming the solar cell protective sheet 3 by extrusion coating will be described.

  The thermoplastic material for forming the sealing material adhesive layer 31 is heated to the softening point or higher, and the heated thermoplastic material is supplied to the surface of the easy-adhesive substrate 1 on the easy-adhesive coating layer 12 side. And the protective material for solar cells shown in FIG. 3 which has the structure where the sealing material adhesion layer 31 was laminated | stacked on the easily-adhesive base material 1 by cooling the thermoplastic material on the easily-adhesive base material 1 3 can be obtained.

  The temperature at which the thermoplastic material (which may be plural as described later) for forming the sealing material adhesion layer 31 is melted is the temperature of this material in the molten state. The base 11 is not deformed by (heat) and is preferably 80 ° C. or higher and 350 ° C. or lower, and particularly preferably 150 ° C. or higher and 300 ° C. or lower. Further, when the thermoplastic material is easily deteriorated, it is preferable to lower the upper limit of the temperature so as to minimize the influence of the deterioration.

  Moreover, the discharge amount from the T-die extruder (T-die film forming machine) of the material for forming the sealing material adhesive layer 31 is the thickness of the target sealing material adhesive layer 31 and the easily adhesive substrate 1. It adjusts suitably according to the moving speed of.

  The easy-adhesive substrate 1 is conveyed in the longitudinal direction at a constant speed by, for example, a roll-to-roll method, and the conveyance speed is from a T-die extruder of a material for forming the sealing material adhesive layer 31. It adjusts suitably according to the discharge amount. In addition, when forming the easy-adhesion coat layer 12 during extrusion coating as described above, the roll to be fed becomes the base material 11.

  According to the above extrusion coating, the adhesive base material can be obtained by simply extruding and laminating the above thermoplastic material from the T-die extruder on the surface of the easy adhesive base layer 1 on the easy adhesive base layer 12 side. 1 can be firmly joined to the sealing material adhesive layer 31, and the solar cell protective sheet 3 can be manufactured with high productivity.

  In the case where the sealing material adhesive layer 31 is composed of a plurality of layers, the thermoplastic material corresponding to each layer is heated to the softening point or higher, and the easy-adhesive substrate 1 on the easy-adhesive substrate 1 is coated. They may be supplied simultaneously or sequentially and the plurality of thermoplastic materials may be cooled simultaneously or individually.

  An example of a method for supplying sequentially is as follows. First, one of a plurality of layers constituting the sealing material adhesive layer 31 is formed on the surface of the easy-adhesive substrate 1 on the side of the easy-adhesion coat layer 12 by the above-described extrusion coating, and the easy-adhesion coat layer 12 in that layer Another one of the plurality of layers constituting the sealing material adhesive layer 31 is laminated on the surface on the opposite side by feeding the thermoplastic material while extruding it. By appropriately repeating this laminating operation, the sealing material adhesive layer 31 having a multilayer structure can be obtained.

  An example of a method for supplying simultaneously is coextrusion coating. Specifically, a plurality of thermoplastic materials are extruded together through parallel slits (at this time, a material discharge port for forming a layer in direct contact with the easy-adhesion coat layer 12 is proximal to the substrate 11. Thus, a layer made of each material is simultaneously formed on the easy-adhesion coat layer 12 of the easy-adhesive substrate 1.

  This coextrusion coating has the advantage in the manufacturing process that the protective sheet 3 for solar cells is obtained by a single laminating process. Further, immediately after the co-extrusion, a plurality of thermoplastic materials are in contact with each other in a molten state, and thus an interaction between them easily occurs, and an adhesive force between the layers constituting the sealing material adhesive layer 31. There is also an advantage that increases.

  As shown in FIG. 3 to FIG. 5, even if another layer is formed on the surface of the base material 11 on the side opposite to the easy-adhesion coat layer 12 of the base material 1, What is necessary is just to form the sealing material contact bonding layer 31 in the surface at the side of the easily bonding coat layer 12 of the material 1. FIG.

  In addition, when the easy-adhesive substrate 1 is subjected to extrusion coating, if the step of forming the easy-adhesion coat layer 12 on the substrate 11 is also performed at the same time, productivity is particularly improved. For example, on the surface on the discharge port side in the base material 11 until the base material 11 reaches the vicinity of the discharge port of the thermoplastic material by feeding the base material 11 in a roll-shaped state. A coating liquid for forming the easy-adhesion coat layer 12 is applied, the coating liquid layer made of this coating liquid is dried to form an easy-adhesion coat layer 12, and an encapsulant adhesive layer is formed on the easy-adhesion coat layer 12 A material for forming 31 may be supplied. Here, since the thermoplastic material supplied from the discharge port has a sufficiently high temperature, the cross-linking reaction of the cross-linking agent contained in the easy-adhesion coat layer 12 is advanced by contacting this material during extrusion coating. be able to. In some cases, a crosslinking reaction between the crosslinking agent contained in the easy-adhesion coat layer 12 and the molten thermoplastic material may occur. In this case, the adhesive force between the sealing material adhesive layer 31 and the easy-adhesion coat layer 12 may be increased. Is more likely to increase. In addition, after the crosslinking reaction of the crosslinking agent in the easy-adhesion coat layer 12 is sufficiently advanced in the drying step of the coating liquid layer, it may be brought into contact with the thermoplastic material supplied from the discharge port. In this case, since the controllability of the thickness of the easy-adhesion coat layer 12 is likely to increase, it is expected that variations in the adhesive force between the sealing material adhesive layer 31 and the easy-adhesion coat layer 12 are reduced.

5. Solar Cell Module FIG. 7 is a schematic cross-sectional view of a solar cell module according to an embodiment of the present invention. The solar cell module 10 according to this embodiment includes a plurality of solar cells 41 made of crystalline silicon, amorphous silicon, or the like, which are photoelectric conversion elements, and a sealing material 42 made of an electrical insulator that seals the solar cells 41. The glass plate 43 laminated on the surface (upper surface in FIG. 7) of the sealing material 42 and the sun as a back surface protection sheet (back sheet) laminated on the back surface (lower surface in FIG. 6) of the sealing material 42 And a battery protection sheet. In the solar cell module 10 according to the present embodiment, the solar cell protective sheet is the solar cell protective sheet 2 or 3 according to the above-described present embodiment.

  In addition, the protective sheet 2 or 3 for solar cells is arrange | positioned so that the easily bonding coating layer 12 may contact the sealing material 42 directly or indirectly through the sealing material adhesive layer 31. FIG. Since the easy-adhesion coat layer 12 is provided, even if the solar cell module 10 repeats thermal expansion / contraction during use, the possibility that the base material 11 is peeled from the sealing material 42 is sufficiently reduced.

  The material of the sealing material 42 is not particularly limited. From the viewpoint of productivity, ethylene-vinyl acetate copolymer (EVA) is often used as a main material, but in recent years, it has a property that is easily deteriorated by ultraviolet rays and responds to the demand for higher productivity. In some cases, a material other than EVA is used as a main material. Examples of such materials other than EVA include polyvinyl butyral (PVB), urethane resin, ionomer resin, styrene resin, and silicone material. Even when the main material of the sealing material 42 is made of such a material, the easy-adhesion coat layer 12 of the easy-adhesive substrate 11 according to this embodiment can be firmly bonded to the sealing material 42. . When the sealing material 42 contains a component capable of reacting with a group having an ethylenically unsaturated bond such as EVA, the coating liquid for forming the easy-adhesion coat layer 12 may contain the component (A). preferable. At this time, the easy-adhesion coat layer 12 of the easy-adhesive substrate 11 according to the present embodiment can be more firmly bonded to the sealing material 42.

  The method for manufacturing the solar cell module 10 is not particularly limited. For example, the solar battery cell 41 is sandwiched between two sheets constituting the sealing material 42, the solar battery protective sheet 2 or 3 is disposed on one surface of the stack, and the glass plate 43 is disposed on the other surface. The solar cell module 10 can be manufactured by performing the lamination process which presses and integrates the whole stack obtained in this way, heating. At this time, the solar cell protective sheet 2 or 3 is adhered to the encapsulant 42 by thermal fusion and chemical interaction between the easy adhesion coat layer 12 or encapsulant adhesive layer 31 and the encapsulant 42. The

  In the lamination step, vacuum lamination may be performed in which heating is performed while the atmosphere is in a reduced pressure environment instead of or in addition to thermal lamination only by heating. In this case, the possibility that bubbles remain at the interface between the members to be crimped can be reduced. Moreover, you may raise heating temperature in steps. In this case, first, based on the difference in coefficient of thermal expansion of the plurality of members constituting the solar cell module 10 by temporarily fixing the sealing material 42 at a temperature at which the progress of the crosslinking is moderate. The generated shearing force is relaxed / absorbed by the sealing material 42 or the like, and then the heating temperature is raised to sufficiently advance the thermal crosslinking of the sealing material 42. If it does in this way, possibility that the peeling between members and the destruction inside a member will generate | occur | produce by the shear force based on the difference of a thermal expansion coefficient can be reduced. Some specific examples of the lamination process are as follows.

Example 1: Vacuum lamination (135 ° C, 3 minutes), Temporarily fixed thermal lamination (135 ° C, 3 minutes), Mainly fixed thermal lamination (150 ° C, 30 minutes)
Example 2: Thermal lamination (150 ° C, 20 minutes)
Example 3: Vacuum lamination (150 ° C., 5 minutes), thermal lamination (150 ° C., 20 minutes)

  In addition, as shown in FIG. 8, it can replace with the glass plate 43 and can use the protection sheet 2 or 3 for solar cells as a surface protection sheet (front sheet). In this case, if a flexible substrate is used for the solar cell 41, the flexible solar cell module 10 can be obtained. Thus, by making the solar cell module 10 flexible, it becomes possible to mass-produce by roll-to-roll. In addition, since the flexible solar cell module 10 can be fitted to an object having an arched or parabolic wall surface, it can be installed on a dome-shaped building or a soundproof wall of a highway. Become.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
(1) Preparation of coating liquid Solid content concentration with respect to 100 parts by mass of polyvinyl butyral (Sekisui Chemical Co., Ltd., ESREC BL-10) having a softening point of 100 ° C. and a butyralization degree of 71 ± 3 mol% Was mixed with xylylene diisocyanate crosslinking agent (Mitsui Chemicals, Takenate D-110N, isocyanate group content 11.5% by mass) with 75% by mass. The ratio (CL / AH ratio) of the amount of isocyanate group of the crosslinking agent in the coating solution to the amount of active hydrogen contained in the hydroxyl group of PVB was 1.0.

(2) Production of protective sheet for solar cell Corona treatment (output 2000W) is applied to one surface of a polyethylene terephthalate (PET) film (Lumirror X10S manufactured by Toray Industries Inc., thickness 125 μm) as a base material, and the corona treatment is applied. The above coating solution was applied to the surface with a Meyer bar. The resulting coating solution layer is allowed to stand in an oven at 120 ° C. for 1 minute together with the substrate to dry the coating solution layer and to proceed with the crosslinking reaction between the crosslinking agent and PVB inside, as shown in FIG. Specifically, a solar cell protective sheet comprising an easy-adhesive base material provided with an easy-adhesion coat layer having a thickness of 0.2 μm on the base material was obtained. In addition, the thickness of the easy-adhesion coat layer was measured by Test Example 1 described later.

(3) Production of solar cell pseudo module A lamination process was performed on each of the following four types of sealing materials and the above solar cell protective sheet to obtain four types of solar cell pseudo modules.
(I) Sealing material 1: Ethylene-vinyl acetate copolymer (EVA) based sealing material (manufactured by SANVIC, ULTRA PEARL, thickness 400 μm), lamination step: the above-mentioned lamination step example 1
(Ii) Sealing material 2: Polyvinyl butyral sealing material (manufactured by Kuraray Co., Ltd., TROSIFOL SOLAR, thickness 700 μm), lamination process: the above-mentioned lamination process example 3
(Iii) Sealing material 3: Silicone-based sealing material (manufactured by Wacker Chemie AG, silicone elastomer, TECTOSIL, thickness 460 μm), lamination process: the above-mentioned lamination process example 3
(Iv) Sealing material 4: Urethane-based sealing material (manufactured by Lubrizol, ESTANE PV-1000), lamination process: the above-mentioned lamination process example 2

[Example 2]
The same operation as in Example 1 was performed except that the thickness of the easy-adhesion coat layer was adjusted to 0.05 μm by adjusting the coating amount of the coating liquid in Example 1, and four types of sealing materials were different. A solar cell pseudo module was obtained.

Example 3
The same operation as in Example 1 was performed except that the coating amount of the coating liquid in Example 1 was adjusted so that the thickness of the easy-adhesion coat layer was 1.5 μm. A solar cell pseudo module was obtained.

Example 4
The same operation as in Example 1 was performed except that the molecular weight distribution of PVB contained in the coating liquid in Example 1 was changed to set the softening point of PVB to 150 ° C. A solar cell pseudo module was obtained.

Example 5
The same operation as in Example 1 was performed except that the content of the crosslinking agent contained in the coating liquid in Example 1 was reduced to obtain a coating liquid having a CL / AH ratio of 0.2, and sealing was performed. Four types of solar cell pseudo modules with different materials were obtained.

Example 6
The same operation as in Example 1 was performed except that the content of the crosslinking agent contained in the coating liquid in Example 1 was reduced to obtain a coating liquid having a CL / AH ratio of 0.5, and sealing was performed. Four types of solar cell pseudo modules with different materials were obtained.

Example 7
Using a T-die extruder (cylinder temperature: 230 to 280 ° C., T-die temperature: 300 ° C.), 70 parts by mass of a first thermoplastic resin made of polyethylene having a density of 900 kg / m ³ and polyethylene having a density of 940 kg / m ³ The surface of the easy-adhesion coat layer side of the easy-adhesive substrate produced in Example 1 using a thermoplastic material obtained by kneading 30 parts by mass of the second thermoplastic resin and 10 parts by mass of titanium dioxide Then, an encapsulant adhesive layer was formed by extrusion coating to a thickness of 100 μm to obtain a solar cell protective sheet having the configuration shown in FIG.
Operation similar to Example 1 was performed with respect to the obtained protection sheet for solar cells, and the solar cell pseudo module using the sealing material 1 was obtained.

Example 8
In Example 1, except that the corona treatment was not performed on the base material, the same operation as in Example 1 was performed to obtain two types (EVA, PVB) of solar cell pseudo modules with different types of sealing materials. It was.

Example 9
NK ester A-TMM-3LM-N (manufactured by Shin-Nakamura Chemical Co., Ltd., active ingredient) in an amount of 5 parts by mass as a component containing component (A) to 100 parts by mass of PVB in the coating liquid used in Example 8 : Pentaerythritol triacrylate monomer, triester: 57%) The same operation as in Example 8 was performed except that a coating liquid was obtained, and two types of sealing materials (EVA, PVB) ) Was obtained.

Example 10
The same operation as in Example 9 was performed except that the amount of NK ester A-TMM-3LM-N added in Example 9 was 10 parts by mass with respect to 100 parts by mass of PVB, and a sealing material was obtained. Two types (EVA, PVB) of solar cell pseudo-modules with different types were obtained.

Example 11
The same operation as in Example 9 was performed except that the amount of NK ester A-TMM-3LM-N added in Example 9 was 50 parts by mass with respect to 100 parts by mass of PVB, and a coating liquid was obtained. Two types (EVA, PVB) of solar cell pseudo-modules with different types were obtained.

Example 12
The same operation as in Example 9 was performed except that the amount of NK ester A-TMM-3LM-N added in Example 9 was 100 parts by mass with respect to 100 parts by mass of PVB, and a coating liquid was obtained. Two types (EVA, PVB) of solar cell pseudo-modules with different types were obtained.

Example 13
In the coating solution used in Example 8, NK ester A-TMMT (available from Shin-Nakamura Chemical Co., Ltd., active ingredient: pentaerythritol tetra) in an amount of 5 parts by mass as a component containing component (A) with respect to 100 parts by mass of PVB. Except that the coating liquid was obtained by adding (acrylate monomer), the same operation as in Example 8 was performed to obtain two types (EVA, PVB) of solar cell pseudo modules having different types of sealing materials.

[Reference Example 1]
Instead of the surface of the easy-adhesive substrate in Example 7 on the side of the easy-adhesion coat layer side, it is one surface of a substrate made of a polyethylene terephthalate (PET) film (Lumirror X10S manufactured by Toray Industries Inc., thickness 125 μm) and corona Except that the surface subjected to the treatment (output 2000 W) was subjected to extrusion coating, the same operation as in Example 7 was performed to obtain a solar cell pseudo module having EVA as the type of the sealing material.

[Reference Example 2]
Polyethylene terephthalate (PET) film (Lumirror X10S manufactured by Toray Industries, Inc., thickness 125 μm) as a base material, which is not subjected to corona treatment on either side, each of the following two types of sealing materials The lamination process was performed using 2 to obtain two types of solar cell pseudo modules.
(I) Sealing material 1: Ethylene-vinyl acetate copolymer (EVA) based sealing material (manufactured by SANVIC, ULTRA PEARL, thickness 400 μm), lamination step: the above-mentioned lamination step example 1
(Ii) Sealing material 2: Polyvinyl butyral sealing material (manufactured by Kuraray Co., Ltd., TROSIFOL SOLAR, thickness 700 μm), lamination process: the above-mentioned lamination process example 3

[Comparative Example 1]
The same operation as in Example 1 was performed except that the molecular weight distribution of PVB contained in the coating liquid in Example 1 was changed to set the softening point of PVB to 190 ° C. A solar cell pseudo module was obtained.

[Comparative Example 2]
The same operation as in Example 1 was performed except that the molecular weight distribution of PVB contained in the coating liquid in Example 1 was changed to set the softening point of PVB to 220 ° C. A solar cell pseudo module was obtained.

[Comparative Example 3]
The same operation as in Example 1 was carried out except that the content of the crosslinking agent contained in the coating solution in Example 1 was increased to obtain a coating solution having a CL / AH ratio of 1.7. Four types of solar cell pseudo modules with different materials were obtained.

[Comparative Example 4]
The same operation as in Example 1 was performed except that the content of the crosslinking agent contained in the coating liquid in Example 1 was increased to obtain a coating liquid having a CL / AH ratio of 2.0, and sealing was performed. Four types of solar cell pseudo modules with different materials were obtained.

[Test Example 1] <Film thickness measurement>
The easy-adhesive base materials produced by the same methods as in Examples 1 to 7 and Comparative Examples 1 to 4 were cut to obtain 5 cm × 5 cm test pieces. The thickness of the easy-adhesion coat layer of this test piece was measured with an ellipsometer (M-2000 manufactured by JA Woollam). The results are as described above.

[Test Example 2] <Measurement of peel adhesion strength>
The peel adhesion strength of the solar cell pseudo modules produced in Examples 1 to 13, Comparative Examples 1 to 4 and Reference Examples 1 and 2 was measured according to ISO 11339: 1993 (JIS K6854-3: 1999). A solar cell pseudo module is cut to a width of 10 mm and a length of 150 mm to obtain a test piece, and a peeling interface is formed between the easily adhesive substrate (the substrate for Reference Examples 1 and 2) and the sealing material. Thus, each of the end part which consists only of an easily-adhesive base material (base material about Reference Examples 1 and 2) and the end part which consists only of a sealing material is a tensile tester (Shimadzu Corporation make, autograph AG- 50 kNX). The average adhesion measured at the time of peeling off the easy-adhesive base material (the base material for Reference Examples 1 and 2) and the sealing material of the test piece at a peeling rate of 300 mm / min in an environment of 23 ° C. and 50% relative humidity The value was defined as the peel adhesion strength between the easy-adhesive substrate (the substrate for Reference Examples 1 and 2) and the sealing material. The results are shown in Table 1 (Examples 1 to 7, Comparative Examples 1 to 4, Reference Example 1) and Table 2 (Examples 8 to 13, Reference Example 2).

[Test Example 3] <Measurement of blocking resistance>
An easy-to-adhesive base material produced by the same method as in each of Examples 1 to 6 and Comparative Examples 1 to 4 was wound around a paper tube having a diameter of 3 inches and a width of 350 mm to produce an evaluation sample. This sample for evaluation was stored in a dry atmosphere at 40 ° C. for 1 week, then unwound and evaluated for blocking resistance according to the following criteria. When it was evaluated as “A”, it was considered acceptable.
A: Unwinding was possible without resistance.
F: Blocking was partially caused and unwinding, but a trace of blocking (discoloration or the like) was observed on the unrolled easily adhesive substrate, or unwinding due to blocking was not possible.
The results are shown in Table 1.

[Test Example 4] <Adhesion measurement>
According to ISO 2409: 1992 (JIS K5600-5-6: 1999), the adhesion between the base material and the easy-adhesion coat layer in each of the easy-adhesive base materials prepared in Examples 1 to 6 and Comparative Examples 1 to 4 was used. Measured. A test piece cut out from the prepared easy-adhesive substrate was cut into the surface of the easy-adhesion coat layer side with a cutter using a 1 mm-interval guide, and 100 squares (10 squares × 1 square square). 10 squares). The notch was made to reach the substrate beyond the interface between the easy-adhesion coat layer and the substrate. Subsequently, a cellophane pressure-sensitive adhesive tape (manufactured by Nichiban Co., Ltd.) was cut into a length of 75 mm, and this was pasted on the portion of the easy-adhesive base material in which cuts were formed in the above-mentioned 100 square grid pattern. At this time, the cellophane pressure-sensitive adhesive tape was uniformly crimped onto the easily adhesive substrate using a squeegee. Before 1 minute had passed since the cellophane adhesive tape was applied, the cellophane adhesive tape was peeled off from the easy-adhesive substrate at an isolation angle of 120 °. The cross-section of the easy-adhesive substrate after peeling the cellophane pressure-sensitive adhesive tape was observed, the number of masses consisting of the easy-adhesion coat layer remaining on the easy-adhesive substrate side was counted, and the residual rate (unit:%) was determined. . The results are shown in Table 1.

  As can be seen from Table 1, the easy-adhesive base material of the example satisfying the conditions of the present invention has high adhesion strength to the sealing material, excellent adhesion between the base material and the easy-adhesive coat layer, and further blocking. Is less likely to occur.

  The protective sheet for solar cells provided with the easily adhesive base material which concerns on this invention is used suitably as a back sheet or a front sheet | seat of a solar cell module, for example.

DESCRIPTION OF SYMBOLS 1 ... Easy-adhesive base material 11 ... Base material 12 ... Easy-adhesion coat layer 12a ... Adhesive surface 2 with a sealing material ... Protective sheet for solar cells 13 ... Fluorine resin layer 14 ... Deposition layer 15 ... Adhesive layer 16 ... Metal sheet DESCRIPTION OF SYMBOLS 3 ... Solar cell protective sheet 31 ... Sealing material adhesion layer 31a ... Adhesive surface 10 with a sealing material ... Solar cell module 41 ... Solar cell 42 ... Sealing material 43 ... Glass plate

Claims (21)

An easy-adhesive base material comprising a base material and an easy-adhesion coat layer laminated on at least one surface of the base material, wherein the easy-adhesion coat layer comprises a polyvinyl butyral having a softening point of 150 ° C. or less and a cross-linking agent has been formed from a coating solution containing the easily adhesive coating layer a crosslinked structure between the cross-linking agent and the polyvinyl butyral is Yes,
The easy-adhesive base material , wherein the coating liquid further contains one or two or more components selected from the group consisting of monomers and oligomers having a group having an ethylenically unsaturated bond .   The content of the cross-linking agent contained in the coating liquid is such that the cross-linking reactive group of the cross-linking agent is 0.1 equivalents or more and 1.5 equivalents per 1 equivalent of the amount of active hydrogen contained in the coating liquid. The easy-adhesive substrate according to claim 1, wherein the active hydrogen contains an active hydrogen contained in a hydroxyl group of the polyvinyl butyral.   The easily adhesive base material of Claim 1 or 2 whose butyralization degree of the polyvinyl butyral in the said easily bonding coat layer is 75 mol% or less.   The easily-adhesive base material according to any one of claims 1 to 3, wherein the crosslinking agent includes an isocyanate-based crosslinking agent.   The easy-adhesive substrate according to any one of claims 1 to 4, wherein a thickness of the easy-adhesion coat layer is 0.01 µm or more and 2.0 µm or less.   The easy-adhesive substrate according to any one of claims 1 to 5, wherein the substrate comprises a film containing a polyester resin. The easily adhesive base material according to any one of claims 1 to 6 , wherein the component further has a group having active hydrogen. A method for producing an easy-adhesive substrate comprising a substrate and an easy-adhesion coat layer laminated on at least one surface of the substrate,
A coating liquid containing polyvinyl butyral having a softening point of 150 ° C. or less , a crosslinking agent, and one or more components selected from the group consisting of monomers and oligomers containing a group having an ethylenically unsaturated bond An easy-adhesive substrate characterized in that it is applied to one surface of the substrate to form a coating liquid layer, and the coating liquid layer is dried to form an easy-adhesion coat layer on the substrate. Production method. The content of the cross-linking agent contained in the coating liquid is such that the cross-linking reactive group of the cross-linking agent is 0.1 equivalents or more and 1.5 equivalents per 1 equivalent of the amount of active hydrogen contained in the coating liquid. It is the quantity used as an equivalent or less, The said active hydrogen is a manufacturing method of Claim 8 containing the active hydrogen which the hydroxyl group of the said polyvinyl butyral has. The manufacturing method of Claim 8 or 9 whose butyralization degree of the polyvinyl butyral contained in the said coating liquid is 75 mol% or less. The crosslinking agent comprises an isocyanate crosslinking agent, production method according to any one of claims 8 10. The manufacturing method according to claim 8 , wherein the component further has a group having active hydrogen. A protective sheet for a solar cell comprising a highly adhesive base material as claimed in any one of claims 1 to 7, the surface opposite to the substrate in the easily adhesive coating layer is in contact with the sealing material A protective sheet for a solar cell, characterized by being a surface for the purpose. An easy-adhesive substrate according to any one of claims 1 to 7 , and a sealing material adhesive layer laminated on the surface of the easy-adhesive substrate on the easy-adhesive coat layer side, The protective sheet for solar cells, wherein a surface of the sealing material adhesive layer opposite to the easy-adhesion coat layer is a surface for contacting the sealing material. The solar cell protective sheet according to claim 14 , wherein the sealing material adhesive layer contains polyvinyl butyral. The said sealing material contact bonding layer is a protection sheet for solar cells of Claim 14 or 15 provided with a multilayered structure. It is a manufacturing method of the protection sheet for solar cells described in Claim 14 or 15 , Comprising: The thermoplastic material for forming the said sealing material contact bonding layer is heated more than the softening point, The said heated said heat | fever A plastic material is supplied to the surface of the easy-adhesive substrate on the side of the easy-adhesive coat layer, and the thermoplastic material on the easy-adhesive substrate is cooled to form the sealing material adhesive layer. Production method. It is a manufacturing method of the protection sheet for solar cells described in Claim 16 , Comprising: About the some thermoplastic material for forming the some layer which comprises the sealing material adhesion layer provided with the said multilayer structure, respectively, a softening point The plurality of heated thermoplastic materials are supplied simultaneously or sequentially to the surface of the easy-adhesive substrate on the side of the easy-adhesive coat layer, and the plurality of heats on the easy-adhesive substrate are heated. A manufacturing method, wherein a plastic material is cooled simultaneously or individually to form an encapsulant adhesive layer having the multilayer structure. The manufacturing method according to claim 17 or 18 , wherein the heat sealing material adhesive layer is formed by extrusion coating of the thermoplastic material onto the easily adhesive substrate. A solar cell module, comprising a solar cell, a sealing material enclosing the solar cell, and two protective members stacked on each of the main surfaces of the sealing material,
Solar cell module at least one of which is characterized by comprising a solar cell protective sheet as described in any one of claims 13 to 16 of the protective member. The solar cell module according to claim 20 , wherein the sealing material contains polyvinyl butyral.

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