JP2013207052A - Resin sheet for sealing solar cell, method of manufacturing the same, and solar cell module sealed by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a resin sheet for sealing a solar cell having excellent long term stability for solar cell quality (heat-humidity resistance, thermal shock cycle resistance and condensing-freezing resistance); a method of manufacturing the same; and a solar cell module.SOLUTION: A heat welded resin sheet for sealing a solar cell has a surface layer composed of silane coupling agent laminated entirely on at least one surface of a polyethylene resin sheet. The polyethylene resin sheet has an area of 50 cm square or more and a thickness of 50 μm to 3 mm. The surface layer is laminated via a corona discharge processing interface obtained by subjecting the one entire surface of the polyethylene resin sheet to corona discharge treatment. The surface layer is a coat having a thickness of 1-20 μm whose thickness distribution is 0.2 or less.

Description

  The present invention relates to a solar cell sealing material mainly composed of a polyolefin-based resin and a solar cell module using the same.

  In recent years, solar cells that directly convert sunlight into electric energy have been widely used from the viewpoints of effective use of resources and prevention of environmental pollution. In order to promote the further spread of solar cells, performance, long-term reliability, etc. required for automobile members and building members are important.

  Generally, a solar cell module protects a solar cell element containing rare metal such as silicon (crystal, polycrystal, amorphous), gallium-arsenic, copper-indium-selenium, etc. with a light-receiving surface side transparent protective member and a back surface side protective member. The solar cell element and the protective member are fixed with a sealing material and modularized. That is, the solar cell module is a laminate of various base materials such as glass, metal, and plastic. The configuration of the solar cell module is slightly different depending on the type of the solar cell element described above, but the property required for the solar cell sealing material is adhesiveness to plastic, glass, metal, and the like. In particular, since the solar cell module is installed outdoors and exposed to a rise in temperature and wind and rain, if the adherence between the adherend and the sealing material is poor, moisture may enter and the solar cell element may be deteriorated.

  In order to manufacture a solar cell module, heat fusion and the use of an adhesive are being studied. However, particularly in the case of different materials, there is a problem that sufficient adhesive strength cannot be ensured. In particular, the surface of silicone rubber, fluoro rubber, polyolefin resin, styrene thermoplastic elastomer, polyimide resin, acrylic resin, etc. does not have highly reactive functional groups, making it difficult to bond other members. there were. Similar problems were found not only in plastic base materials but also in inorganic base materials such as glass and metal. Therefore, as a method for modifying such a base material and improving the lamination property, modifying the resin or applying a primer treatment to the surface of the base material is performed. However, in order to obtain a predetermined modification effect, there were problems in the manufacturing process such as requiring a relatively large amount of primer and taking a long processing time.

  In order to improve adhesiveness, a sealing material containing a modified polyolefin resin and a silane coupling agent has been proposed (Patent Document 1). However, there is a problem that processing time and manufacturing cost are required due to the modification step. Moreover, it is intended for a so-called filler compound that is added to the resin to improve the physical properties of the resin, and is not intended to laminate the base material.

  There has been proposed a sealing material made of an ethylene copolymer composition imparted not only with adhesiveness but also with transparency and heat resistance (Patent Document 2). However, in this method, since it is necessary to introduce a functional group not only on the surface but also on the whole polymer, there is a problem that not only the cost is increased but also the manufacturing process becomes complicated.

  Patent Document 3 proposes a solar cell encapsulating sheet that has been given adhesion by applying a surface treatment such as corona discharge treatment to a resin sheet, and when stronger adhesion is required, It discloses that a silane coupling agent or the like may be added to the material of the sealing sheet as necessary. However, in this modification method, since the surface of the resin layer containing the silane coupling agent is subjected to corona discharge treatment, the functional group derived from the silane coupling agent and the functional group derived from the corona discharge treatment are Although all functional groups exist independently on the surface of the base material, the functional groups are not chemically bonded to the base resin itself. This is considered to be insufficient, and sufficient adhesiveness may not be obtained.

  On the other hand, in Patent Document 4, for the purpose of improving the adhesion of the polyolefin surface and preventing the polyolefin surface coating layer from peeling off, a reactive functional group is introduced into the surface of the polyolefin by corona discharge treatment or the like, and is composed of a silane compound in a solvent. A cement reinforcement with a coating is proposed. However, in this method, since the polyolefin flat plate is immersed in the silane compound solution to form a film, the thickness of the silane compound film and the uniformity of the film quality are affected. There is a problem with sex. Further, in this method, the entire surface of the substrate can be processed, but for example, it is difficult to perform surface treatment on only one side, which is sometimes necessary in application to a sealing resin sheet for solar cells, and the structure of the laminate is Not only limited, but environmental problems such as dangerous or dangerous work environment when processing large area as required by solar cell sealing resin sheet, water washing and waste liquid treatment The problem of the operation | work etc. to which etc. are needed, and the economical problem that an installation is large-scale and expensive arise.

JP 2011-77360 A JP 2009-177089 A JP 2010-222541 A Japanese Patent Laid-Open No. 05-156054

  The object of the present invention is to improve the above-mentioned problems of the prior art, and to provide a solar cell encapsulating resin sheet excellent in long-term stability of solar cell quality (heat and humidity resistance, cold and heat cycle resistance, and condensation freezing resistance), and its production A method and a solar cell module are provided.

  In view of the above-mentioned present situation, the present inventors have intensively studied to provide a low-cost solar cell encapsulating resin sheet that requires a large area and a uniform and large adhesive strength on the entire surface.

  For example, the above-described modification method of Patent Document 4 is attractive as a technique applied to a solar cell sealing resin sheet. However, in general, even if a substrate having a modified surface is used as a large-area melt-adhesive film, the composition of the modified surface is mixed with the substrate resin and sufficient adhesive strength cannot be obtained, or the melt-adhesion temperature It is considered that sufficient adhesive strength cannot be obtained uniformly in the surface due to the non-uniformity in the surface. In addition, as described above, the method of Patent Document 4 has a problem that the thickness and quality of the silane compound film are lacking, surface treatment on only one side is difficult, and environmental safety measures are required.

  However, as a result of intensive studies, the present inventors have determined that a process window sufficient at the melt adhesion temperature can be obtained by using a specific sealing resin sheet even when a substrate having a modified surface is used as the melt adhesion film. In addition, the present inventors have found that a solar cell encapsulating resin sheet can be obtained from which the physical properties required for a solar cell encapsulant can be obtained.

  That is, even when a base material having a modified surface is used as a melt-adhesive film, by using a specific resin sheet as defined in the present invention, various base materials such as glass, metal, and plastic can be used. In addition, the present inventors have found that it can be suitably used as a solar cell sealing material having excellent adhesiveness. As a result of carrying out the durability test of the solar cell module sealed using such a sealing resin sheet for solar cells of the present invention, long-term stability was shown.

  Such a present invention is a heat-welding solar cell sealing resin sheet in which a surface layer made of a silane coupling agent is laminated on the entire surface of at least one of a polyethylene resin sheet, and the polyethylene resin sheet is It has an area of 50 cm square or more and a thickness of 50 μm to 3 mm, and the surface layer is laminated via a corona discharge treatment interface obtained by corona discharge treatment of the one whole surface of the polyethylene resin sheet, and It is related with the sealing resin sheet for solar cells whose surface layer is a film | membrane with a thickness of 1-20 micrometers whose distribution represented by following Numerical formula 1 regarding the thickness is 0.2 or less.

  From the viewpoint of maintaining the adhesive strength uniformly and stably on the entire surface, a preferred embodiment is that the thickness of the coating is 5 to 15 μm, more preferably 8 to 12 μm.

  Further, the present invention is a method for producing the solar cell sealing resin sheet, the step of forming a corona discharge treatment interface by corona discharge treatment of at least one entire surface of the polyethylene resin sheet, and It is related with the manufacturing method of the sealing resin sheet for solar cells including the process of forming the said surface layer by apply | coating the organic solvent solution of the said silane coupling agent on a corona discharge process interface with a bar coater, and drying.

  A preferred embodiment is to dissolve the organic solvent solution by dissolving 3 to 20 parts by weight of the silane coupling agent in 100 parts by weight of isopropanol, and more preferably 8 to 15 parts by weight of the silane coupling agent. It is to make a solution.

  A preferred embodiment is that the silane coupling agent is a silane coupling agent having a first functional group and a second functional group having reactivity with a hydroxyl group. By applying a corona discharge treatment and coating a silane coupling agent having a second functional group having reactivity with a hydroxyl group and a first functional group, it has excellent adhesion to various substrates such as glass, metal and plastic. A solar cell sealing material is obtained.

  A preferred embodiment is selected from the group consisting of the second functional group as hydrolyzable silicon and the first functional group consisting of an epoxy group, an isocyanate group, a hydrolyzable silicon group, a thionol group, and an amino group. One or more types.

  Furthermore, this invention relates to the solar cell module formed by sealing with the vacuum laminator using such a sealing resin sheet for solar cells of this invention.

  Even if the sealing resin sheet for solar cells of the present invention is a melt-adhesive film having a modified surface, it is a low-cost solar cell sealing resin that requires a large area and a uniform and large adhesive strength over the entire surface. A solar cell module that has sufficient characteristics as a sheet and is sealed using the sheet exhibits excellent long-term quality stability (heat and humidity resistance, cold and heat cycle resistance, and condensation freezing resistance).

Solar cell module of the present invention Solar cell module of the present invention

  Details of the present invention will be described below.

(Solar cell sealing resin sheet)
The solar cell sealing resin sheet of the present invention is a sealing material obtained by subjecting at least one entire surface of a polyethylene resin sheet to corona discharge treatment, and further coating with a silane coupling agent. The thickness of the molded body can be exemplified by 50 μm to 3 mm, and is preferably 100 μm to 1 mm from the viewpoint of handling and imparting insulation properties. Moreover, it is a sealing resin sheet for solar cells and has a large area of 50 cm □ or more.

  When manufacturing a solar cell module, the solar cell sealing resin sheet of the present invention is inserted between a solar cell element and a protective member and heated and melted to bond and seal between them. used.

  The heating and melting is preferably performed using a vacuum laminator. Moreover, as the temperature for heating and melting, the solar cell sealing resin sheet of the present invention has a wide process window and can be carried out at 105 ° C. to 180 ° C., preferably 125 ° C. to 160 ° C., more preferably. It can implement at 135-150 degreeC.

  Among the protective members, for example, there are those coated with a primer for imparting adhesiveness, in which case the sealing resin sheet is imparted with adhesiveness only on one side contacting the solar cell element. It is sufficient, and imparting adhesiveness to both surfaces causes an increase in cost. The sealing resin sheet for solar cells of the present invention can easily form the surface layer according to the present invention only on one side, and it is also preferable to form a corona discharge treatment interface or surface layer only on one entire surface. It is a form.

(Solar cell module)
The solar cell module of this invention is obtained by sealing the cell for solar cells through the sealing resin sheet for solar cells of this invention between the light-receiving surface side transparent protective member and the back surface side protective member.

  In the solar cell module, in order to sufficiently seal the solar cell, there are roughly two sealing methods, crystalline and amorphous. In the case of a crystalline solar cell, as shown in FIG. 1, the light receiving surface side transparent protective member 1, the light receiving surface side sealing material 3 </ b> A, the solar cell 4, the back surface side sealing material 3 </ b> B, and the back surface side protective member 2 are provided. In the case of being laminated and amorphous, as shown in FIG. 2, the light receiving surface side transparent protective member 1, the solar cell 4 (in contact with the light receiving surface side transparent protective member), the back surface side sealing material 3B, The back surface protection member 2 is laminated and integrally molded with a vacuum laminator.

Integrated molding with a vacuum laminator is performed at a temperature of 105 to 180 ° C., further 125 to 160 ° C., particularly 135 to 150 ° C., a degassing time of 0.1 to 5 minutes, a press pressure of 0.1 to 1.5 kgf / cm ² , What is necessary is just to heat-press in press time 5-15 minutes. At the time of this heating and pressurization, the sealing resin sheet for solar cell of the present invention used for the light receiving surface side sealing material 3A and / or the back surface side sealing material 3B is the light receiving surface side transparent protective member 1, the back surface side transparent member. 2 and the solar cell 4 can be sealed by closely contacting and integrating the solar cell 4.

  By using the encapsulant of the present invention for a solar cell having such a configuration, the encapsulant is used for a long period of time. It is possible to suppress a decrease in power generation performance and to have excellent durability.

  The light-receiving surface side transparent protective member used in the present invention is used in the form of a film, a sheet, or a plate. Usually, a material having practical strength and transparency such as a silicate glass or a polycarbonate plate is used, and a glass substrate is particularly preferable. As for the thickness of a glass substrate, 0.1-10 mm is common, and 0.3-5 mm is preferable. The glass substrate may generally be chemically or thermally strengthened.

  The back surface protection member used in the present invention is used in the form of a film, a sheet, or a plate. A laminated body of glass, aluminum foil, or plastic film is preferably used for the back surface protection member. Examples of the resin used for the plastic film include polyvinyl fluoride, polyethylene terephthalate, polyethylene naphthalate, polyethylene, and tetrafluoroethylene. -An ethylene copolymer etc. are mentioned, However, It is not limited to these. The back surface protection member is a single layer or a laminate having heat resistance, moisture resistance, weather resistance, and insulation generally called a back sheet.

  In addition, the solar cell of this invention has the characteristics in the sealing material used for the light-receiving surface side and / or back surface side as above-mentioned. Therefore, members other than the sealing material such as the light-receiving surface side transparent protective member, the back surface side protective member, and the solar battery cell are not particularly limited, and may have the same configuration as a conventionally known solar battery. That's fine.

(Polyethylene resin sheet)
Examples of the polyethylene resin that is a material for the polyethylene resin sheet according to the present invention include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. These may be used alone or in combination of two or more. Can do. Low-density polyethylene is preferred from the viewpoint of cost and followability of unevenness during melt bonding.

  For polyethylene resins, stabilizers such as antioxidants, metal deactivators, phosphorus processing stabilizers, UV absorbers, UV stabilizers, fluorescent brighteners, metal soaps, antacid adsorbents, etc., as necessary, Additives such as cross-linking agents, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing materials, pigments, dyes, flame retardants and antistatic agents may be added within the range not impairing the effects of the present invention. Good.

  In addition, when the above additive material (other resin, rubber, stabilizer and / or additive) is used, even when the additive material is previously added to the polyolefin resin, the polyethylene resin is melted. It may be added to.

  The method for forming the polyethylene resin sheet is not particularly limited. In addition, the order and method of mixing and melt-kneading of materials added as necessary are not particularly limited.

  The method for producing a polyethylene resin sheet according to the present invention is not particularly limited. For example, after dry blending, melt-kneading a polyethylene resin composition and other compounding agents, various extrusion molding machines, injection molding machines, It can be molded into a sheet-like molded body using a calendar molding machine, an inflation molding machine, a roll molding machine, or a hot press molding machine.

  The heating temperature at the time of melt kneading is preferably 130 to 300 ° C. in that the polyethylene resin is sufficiently melted and is not thermally decomposed. The melt kneading time is usually 30 seconds to 60 minutes.

  Further, as the melt kneading apparatus, an extruder, a Banbury mixer, a mill, a kneader, a heating roll, or the like can be used. From the viewpoint of productivity, a method using a single-screw or twin-screw extruder is preferred. Moreover, in order to mix each material sufficiently uniformly, the melt kneading may be repeated a plurality of times.

(Corona discharge treatment interface)
The corona discharge treatment interface according to the present invention is formed on the entire surface of at least one of the polyethylene resin sheets according to the present invention on the surface on which the surface layer according to the present invention is laminated. The purpose of the formation is to introduce a reactive functional group into the surface layer so that the silane coupling agent according to the present invention is firmly bonded to the sheet surface.

The formation method includes, for example, a method in which a Shinko Corona Master PS series is used, and a polyethylene resin sheet is subjected to corona discharge treatment under conditions of a treatment density of 138 W · min / m ² and a treatment speed of 12 m / min.

(Surface layer)
The surface layer according to the present invention is a layer composed of a film containing a silane coupling agent as a main component, which will be described later, by applying and drying the silane coupling agent on the surface of the substrate subjected to the corona discharge treatment. It is formed.

  As a coating method of the silane coupling agent according to the present invention, the surface layer can be laminated as a coating having a thickness of 1 to 20 μm with a distribution represented by the following formula 1 relating to the thickness of 0.2 or less. If it is a method, it will not specifically limit and a well-known method can be used.

  For example, such known lamination methods include bar coating, roll coating, spray coating, dip coating, spin coating, laminar flow coating, die coating, gravure coating, knife coating, curtain coating, rod coating, air doctor coating, Examples include blade coating and comma coating.

  In the case of a polyethylene resin sheet as a base material according to the present invention, from the viewpoint of stably forming a film with the thickness with in-plane uniformity of the thickness distribution, bar coating, roll coating, spin coating, laminar Flow coating, die coating, gravure coating, and the like are preferable, and it is more preferable to bar coat an organic solvent solution of a silane coupling agent with a bar coater.

  As a material containing a silane coupling agent preferably used for coating, the silane coupling agent may be directly coated as long as the film having the thickness can be stably formed with in-plane uniformity of the thickness distribution. However, from the viewpoint of manufacturing a large-area solar cell sealing resin sheet of the present invention in large quantities with inexpensive manufacturing equipment, it is diluted with a suitable solvent for viscosity adjustment and for controlling the thickness of the coating layer. It is preferable to coat it.

  As the solvent used in the organic solvent solution of the silane coupling agent of the present invention, it can be suitably used as long as the silane coupling agent is dissolved or uniformly dispersed, but from the viewpoint of cost and handling, Hydrocarbon solvents (toluene, xylene, hexane, cyclohexane, etc.), alcohol solvents (methanol, ethanol, propanol, isopropanol, etc.), halogen solvents (dichloromethane), etc. are preferred, and isopropanol is more preferred.

  Any concentration of the silane coupling agent in the organic solvent solution can be used, but about 1% to 80% is preferable. When the concentration is 1% or less, the surface treatment agent may not sufficiently react, and when it exceeds 80%, application becomes difficult when the viscosity of the silane coupling agent is high. However, this is not the case when the viscosity of the surface treatment agent is low. In the case of isopropanol as a solvent, it is more preferable to use an organic solvent solution in which 3 to 20 parts by weight of a silane coupling agent is dissolved in 100 parts by weight of isopropanol.

  The film thickness of the coating according to the present invention after drying can be appropriately selected according to the purpose, but it is required to be 1 to 20 μm from the viewpoint of making an inexpensive sheet stably realizing high adhesive strength on the entire surface. . If the thickness is less than 1 μm, functional group introduction to the substrate surface may not be sufficient. If the thickness exceeds 20 μm, the physical properties of the substrate may decrease and the amount of silane coupling agent used increases. It becomes disadvantageous in cost. This film thickness is sealed while preventing the silane coupling agent from chemically bonding to the material to be sealed, such as glass, and how much the coupling agents are bonded to each other and melt into the base material during melt bonding. It is an important factor that determines whether to maintain the softness to follow the unevenness of the material to be achieved, and it is believed that this film thickness provides the breadth of the melt bonding temperature process window according to the present invention.

  Moreover, in order to advance reaction of a 2nd functional group and a hydroxyl group smoothly, you may add a reaction catalyst as needed. Furthermore, in order to complete reaction, you may heat in oven etc. as needed. However, since the first functional group may react if heated under too severe conditions, the heating temperature is preferably 30 to 120 ° C, more preferably 40 to 80 ° C.

  The base material having a modified surface thus obtained is suitably used for various industrial applications. In particular, it is preferably used in the field of films and sheets, which are often used after being laminated or laminated. Any second functional group having reactivity with the hydroxyl group can be used as long as it is reactive with the hydroxyl group.

(Silane coupling agent)
Specific examples of the second functional group include hydrolyzable silicon group, carboxyl group, acid anhydride group, epoxy group, amino group, isocyanate group, hydroxyl group, phenolic hydroxyl group, acetyl group, benzoyl group, acetoxy group, benzoyloxy Group, halide group and the like. Of these, hydrolyzable silicon groups are preferred because of their high reactivity with hydroxyl groups and selective reaction.

  These functional groups may be present alone or in a plurality.

  The first functional group is a functional group introduced on the surface of the base material, and is appropriately selected according to the characteristics required for the base material. Specific examples of the first functional group include an alkyl group (methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-hexyl group, Cyclohexyl group, n-octyl group, n-decyl group, lauryl group, stearyl group, benzyl group, etc.), alkenyl group (vinyl group, allyl group, dienyl group etc.), aryl group (phenyl group, naltyl group etc.), hydroxy Methyl group, hydroxyethyl group, hydroxyphenyl group, methoxy group, ethoxy group, phenoxy group, allyloxy group, acetyl group, benzoyl group, acetoxy group, benzoyloxy group, (meth) acryloyl group, epoxy group, carboxyl group, acid Examples thereof include an anhydride group, an isocyanate group, a hydrolyzable silicon group, a thiol group, and a halide group.

  Alkyl groups (especially, long-chain alkyl groups are preferred) when it is desired to have lipophilicity on the surface of the substrate, but reactive functional groups when it is desired to have adhesion and reactivity with other materials. However, when it is desired to have water repellency, a halide group (particularly a fluorine group) is preferably used.

  These functional groups may be present alone or in a plurality.

  Among these, it is particularly desirable that it is one selected from the group consisting of an epoxy group, an isocyanate group, a hydrolyzable silicon group, a thiol group, and an amino group.

  For example, when a substrate having a modified surface is to be bonded to glass or metal, the first functional group is preferably an epoxy group, an isocyanate group, a hydrolyzable silicon group, etc., and is bonded to a vulcanized rubber. When it is desired to combine them, an alkenyl group or a thiol group is preferable.

  When performing bonding, a reaction catalyst or a crosslinking agent may be added as necessary.

  The silane coupling agent may include a silicon atom, a titanium atom, an aluminum atom, or a carbon atom. In particular, those containing silicon atoms are preferably used.

  Specific examples of the silane coupling agent containing a silicon atom include, for example, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, phenyltrimethoxysilane, Phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltriethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxy Propyltriethoxysilane, 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3- Methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, p-styryltrimethoxysilane, N-2 (aminoethyl) 3-aminopropylmethyldimethoxysilane, N-2 (aminoethyl) 3-aminopropyltri Methoxysilane, N-2 (aminoethyl) 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminotriethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylide ) Propylamine, N-phenyl-3-aminopropyltrimethoxysilane, N- (vinylbenzyl) -2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, vinyltrichlorosilane, 3-chloropropyltrimethoxysilane, 3-chloropropyltriethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-ureidopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis (Triethoxysilylpropyl) tetrasulfide, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane, tetramethoxysilane, tetraethoxysilane, trimethoxy Examples include silane, triethoxysilane, hexamethyldisilazane, hexyltrimethoxysilane, and decyltrimethoxysilane.

  Specific examples of the silane coupling agent containing a titanium atom include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, titanium acetylacetonate, titanium tetraacetylacetonate. , Titanium ethyl acetoacetate, titanium octanediolate, titanium lactate, titanium triethanolamate, polyhydroxy titanium stearate, isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl (N-aminoethyl-aminoethyl) ) Titanate, tetra (2,2-diallyloxymethyl-1-butyl) bis (ditridecyl) phosphite titanate Bis (dioctyl pyrophosphate) oxy acetate titanate, bis (dioctyl pyrophosphate) ethylene titanate, isopropyl dimethacryl isostearoyl titanate, and the like.

  Specific examples of the silane coupling agent containing an aluminum elementary atom include aluminum isopropylate, monosec-butoxyaluminum diisopropylate, aluminum sec-butyrate, aluminum ethylate, ethyl acetoacetate aluminum diisopropylate, aluminum tris (ethylacetate). Acetate), alkyl acetoacetate aluminum diisopropylate, aluminum monoacetylacetonate bis (ethylacetoacetate), aluminum tris (acetylacetonate), aluminum monoisopropoxymonooroxyethylacetoacetate, cyclic aluminum oxide isopropylate, cyclic aluminum Oxide octylate, cyclic aluminum oxide stearate That.

  In addition to these, compounds that are generally commercially available as primers and that have a plurality of hydrolyzable silicon groups in one molecule, or compounds that have hydrolyzable silicon groups and other substituents can also be suitably used. . As such, Toray Dow Corning Primer APZ series, Arakawa Chemical Composeran series and the like are exemplified.

  Specific examples are shown below, but the present invention is not limited to the following examples. In the following examples and comparative examples, “parts” and “%” represent “parts by weight” and “% by weight”, respectively.

(Corona discharge treatment)
After the surface of the polyethylene resin sheet was washed with isopropyl alcohol, a corona discharge treatment was performed using a Shinko Corona Master PS series under conditions of a treatment density of 138 W · min / m 2 and a treatment speed of 12 m / min. After processing one side, the other side was processed in the same manner.

  (Application of Silane Coupling Agent) A 10 wt% isopropyl alcohol solution of various silane coupling agents was prepared, and the wire bar was attached so that the wet coating film thickness was 10 μm on the corona-treated substrate surface. Coating was carried out with the bar coater used. The coated substrate was air-dried at room temperature for 15 minutes, and then dried in a hot air oven at 50 ° C. for 15 minutes to obtain a substrate having a modified surface. When a silane coupling agent was applied on the sheet-like substrate by this method, the distribution represented by the following formula 1 was 0.2 or less in any sample.

(Adhesion evaluation)
For the adhesive strength with glass, AG-2000A manufactured by Shimadzu Corporation was used, and a 180 ° peel test was performed at 23 ° C. and a tensile test speed of 50 mm / min. The test sample was produced by the following method. Glass (3.2 mm thickness, manufactured by Asahi Glass Co., Ltd.) / Surface-treated polyethylene sheet (400 μm thickness) / back sheet for sealing solar cells (manufactured by Toyo Aluminum Co., Ltd., TOYAL SOLAR FA20 / AL30 / BPET50 / LE50), vacuum laminator (N -It was made to press-fit with PC company make, LM-50x50-S). The conditions for integral molding were 135 ° C., degassing time of 5 minutes, pressing pressure of 1 kgf / cm ² , and pressing time of 15 minutes.

(Evaluation of heat and humidity resistance of solar cell module; DH1000 test)
A solar cell crystal having a length of 400 mm and a width of 400 mm in the configuration of glass / sealing material / cell / sealing material / back sheet (see FIG. 1) from the light-receiving surface side using the solar cell sealing material sheet of the present invention. A sheet for solar cell encapsulant of the present invention 410 mm long and 410 mm wide is sandwiched between a glass substrate and a back sheet of 420 mm long and 420 mm long (made by ISOVOLTA: ICOSOLAR 0711), and a vacuum laminator (manufactured by NPC; A vacuum laminator LM-50 X 50-S) was integrally formed. The conditions for the integral molding were 135 ° C., degassing time of 5 minutes, press pressure of 1 kgf / cm 2, and pressing time of 15 minutes to obtain a solar cell module.

  The produced solar cell module was irradiated with pseudo-sunlight at 25 ° C. and an irradiation intensity of 1000 mW / cm 2 by a solar simulator whose spectrum was adjusted to AM 1.5, and the open voltage [V] of the solar cell and the nominal maximum per cm 2 The output operating current [A] and the nominal maximum output operating voltage [V] were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the solar cell module is left in an environment of a temperature of 85 ° C. and a humidity of 85% RH for 1000 hours, and a heat and humidity resistance test is performed. ] And the superiority or inferiority of the heat and humidity resistance was determined. The judgment of superiority or inferiority was made as follows.
○: The value obtained by dividing the nominal maximum output after the 1000 hour heat and humidity resistance test by the initial value (Pmax retention rate) is 95.0% or more and the appearance is good. ×: The nominal maximum output after the 1000 hour heat and humidity resistance test is divided by the initial value. Value Pmax retention) is less than 95.0% or abnormal appearance (wrinkles and peeling)

(Evaluation of cold and heat cycle resistance of solar cell module; TC200 test)
The solar cell module produced by the above method was irradiated with pseudo-sunlight with an irradiation intensity of 1000 mW / cm ² by a solar simulator whose spectrum was adjusted to AM1.5, and the open voltage [V] of the solar cell and 1 cm The nominal maximum output operating current [A] and the nominal maximum output operating voltage [V] per ² were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the manufactured solar cell module was left for 200 cycles in an environment where the temperature was −40 ° C. to + 85 ° C. (temperature increase / decrease rate of 100 ° C./hr) for one cycle. For the battery module, the nominal maximum output [W] was determined in the same manner as described above, and the superiority or inferiority of the cold-heat cycle resistance was determined. The judgment of superiority or inferiority was made as follows.
○: Nominal maximum output after 200 cycles of thermal cycle test divided by initial value Pmax retention ratio) is 95.0% or more and good appearance ×: Nominal maximum output after 200 cycles of thermal cycle test as initial value Divided value Pmax retention ratio) is less than 95.0% or abnormal appearance (wrinkles and peeling)

(Condensation freezing resistance evaluation of solar cell module; TC50 & HF10 test)
The solar cell module produced by the above method was irradiated with pseudo-sunlight with an irradiation intensity of 1000 mW / cm ² by a solar simulator whose spectrum was adjusted to AM1.5, and the open voltage [V] of the solar cell and 1 cm The nominal maximum output operating current [A] and the nominal maximum output operating voltage [V] per ² were measured, and the initial value of the nominal maximum output [W] (JIS C8911 1998) was determined from these products.

Next, the prepared solar cell module was allowed to stand for 50 cycles in an environment where the temperature was −40 ° C. to + 85 ° C. (temperature increase / decrease rate of 100 ° C./hr), and further −40 ° C. to + 85 ° C./85% RH ( 10 cycles under an environment where the temperature increasing / decreasing rate is 100 ° C./hr), the condensation freezing cycle test is performed, and the nominal maximum output [W] is obtained for the solar cell module after being left in the same manner as described above. The superiority or inferiority of the cold-heat cycle resistance was judged. The judgment of superiority or inferiority was made as follows.
○: The value Pmax retention ratio obtained by dividing the nominal maximum output after the TC50 & HF10 test by the initial value) is 95.0% or more and the appearance is good X: The value Pmax retention ratio obtained by dividing the nominal maximum output after the TC50 & HF10 test by the initial value) Less than 95.0% or abnormal appearance (wrinkles and peeling)

Example 1
A polyethylene sheet (low density polyethylene, 400 μm thickness) was subjected to corona discharge treatment. The surface of the base material was coated with 3-isocyanatopropyltrimethoxysilane (Y-5187 manufactured by Toray Dow Corning) as a silane coupling agent on a polyethylene sheet subjected to corona discharge treatment.

  The obtained surface-modified polyethylene sheet (sealant for solar cells) was subjected to degassing time at 135 ° C. using a vacuum laminator LM-50 X 50-S manufactured by NPC. Bonding was performed under conditions of 5 minutes, a press pressure of 1 kgf / cm 2, and a press time of 15 minutes (see adhesive evaluation).

  The obtained sample was subjected to a 180 ° peel test at 23 ° C. and a tensile test speed of 50 mm / min using AG-2000A manufactured by Shimadzu Corporation.

  In addition, the obtained surface-modified polyethylene sheet (sealant for solar cell) was formed from the light-receiving surface side in a configuration of glass / encapsulant / cell / encapsulant / back sheet (see FIG. 1), 400 mm in length. A sheet for solar cell encapsulating material of the present invention 410 mm long and 410 mm wide is sandwiched between a crystal glass substrate for 400 mm solar cell and a back sheet 420 mm long and 420 mm wide (ICOSOLAR 0711 manufactured by Isovolta Co., Ltd.), and a vacuum laminator ( NPC; vacuum laminator LM-50 X 50-S). The conditions for the integral molding were 135 ° C., degassing time of 5 minutes, press pressure of 1 kgf / cm 2, and pressing time of 15 minutes to obtain a solar cell module. The obtained solar cell module was subjected to heat / moisture resistance evaluation, cold / heat cycle resistance evaluation, and condensation / freezing resistance evaluation. The results are shown in Table 1.

(Example 2)
The same procedure as in Example 1 was performed except that X-12-965P manufactured by Shin-Etsu Chemical was used as the silane coupling agent. The results are shown in Table 1.

(Example 3)
The same procedure as in Example 1 was carried out except that Toray Dow Corning Primer APZ-6601 was used as the silane coupling agent. The results are shown in Table 1.

Example 4
It was carried out in the same manner as in Example 1 except that it was treated at 170 ° C. as an integral molding condition. The results are shown in Table 1.

(Comparative Example 1)
After corona discharge treatment, the same procedure as in Example 1 was performed except that a polyethylene sheet not coated with a silane coupling agent was used. The results are shown in Table 1.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that a polyethylene sheet coated with a silane coupling agent without using corona discharge treatment was used. The results are shown in Table 1.

(Comparative Example 3)
The same procedure as in Example 2 was performed except that a polyethylene sheet coated with a silane coupling agent without using corona discharge treatment was used. The results are shown in Table 1.

(Comparative Example 4)
The same procedure as in Example 3 was performed except that a polyethylene sheet coated with a silane coupling agent without using corona discharge treatment was used. The results are shown in Table 1.
(Comparative Example 5)
After corona discharge treatment, the same procedure as in Example 1 was performed except that a silane coupling agent was immersed and a polyethylene sheet having a surface layer thickness distribution (Equation 1) of 0.8 was used. The results are shown in Table 1.

1. 1. Light-receiving surface side transparent protective member Back side transparent protective member 3A. Light-receiving surface side sealing material 3B. 3. Back side sealing material Solar cell

Claims (6)

A heat-weldable solar cell encapsulating resin sheet in which a surface layer made of a silane coupling agent is laminated on the entire surface of at least one of a polyethylene resin sheet,
The polyethylene resin sheet has an area of 50 cm square or more and a thickness of 50 μm to 3 mm,
The surface layer is laminated via a corona discharge treatment interface obtained by corona discharge treatment of the entire one surface of the polyethylene resin sheet, and
A sealing resin sheet for a solar cell, wherein the surface layer is a coating having a thickness of 1 to 20 μm with a distribution represented by the following formula 1 regarding the thickness of 0.2 or less.
It is a manufacturing method of the sealing resin sheet for solar cells according to claim 1, forming the corona discharge treatment interface by corona discharge treating at least one whole surface of the polyethylene resin sheet, and
The manufacturing method of the sealing resin sheet for solar cells which includes the process of forming the said surface layer by apply | coating the organic solvent solution of the said silane coupling agent on the said corona discharge process interface with a bar coater, and drying.   The said organic solvent solution is a solution which melt | dissolved 3-20 weight part of silane coupling agents in 100 weight part of isopropanol, The manufacturing method of the sealing resin sheet for solar cells of Claim 2 characterized by the above-mentioned.   The solar cell sealing resin sheet according to claim 1, wherein the silane coupling agent has a first functional group and a second functional group having reactivity with a hydroxyl group.   The second functional group of the silane coupling agent is hydrolyzable silicon, and the first functional group is selected from the group consisting of an epoxy group, an isocyanate group, a hydrolyzable silicon group, a thionol group, and an amino group. It is a seed | species or more, The sealing resin sheet for solar cells of Claim 4 characterized by the above-mentioned.   The solar cell module formed by sealing with the vacuum laminator using the sealing resin sheet for solar cells of Claim 4 or 5.