JPWO2011096248A1 - Light reflecting film for solar power generation, method for producing the same, and reflector for solar power generation using the same - Google Patents

Abstract

In addition to preventing the regular reflectance of the solar power generation light reflection film from decreasing due to deterioration of the protective layer, etc., it is lightweight and flexible, reducing the manufacturing cost and enabling large area production and mass production. Provided are an excellent light reflection film for solar power generation having good regular reflectance with respect to sunlight, a method for producing the same, and a solar power generation reflection device using the same. The light reflecting film for solar power generation of the present invention is for solar power generation in which two or more protective layers are provided on the resin substrate as a constituent layer on the light source side from an adhesive layer, a metal reflecting layer, and the metal reflecting layer. A light reflecting film, wherein at least one of the protective layers is peelable.

Description

  The present invention relates to a light reflection film for solar power generation, a method for producing the same, and a reflection device for solar power generation using the same.

  Natural energy such as coal energy, biomass energy, nuclear energy, wind energy, and solar energy is currently being considered as alternative energy to replace fossil fuel energy such as oil and natural gas. The most stable and abundant amount of natural energy is considered to be solar energy.

  However, although solar energy is a very powerful alternative energy, from the viewpoint of utilizing it, (1) the energy density of solar energy is low, and (2) it is difficult to store and transfer solar energy. Is considered to be a problem.

  On the other hand, it has been proposed to solve the problem that the energy density of solar energy is low by collecting solar energy with a huge reflector.

  Since the reflection device is exposed to ultraviolet rays, heat, wind and rain, sandstorms, and the like caused by solar heat, a glass mirror has been conventionally used. Glass mirrors are highly durable against the environment, but they are damaged during transportation or heavy, so there is a problem that the construction cost of the plant is increased because of the strength of the mount on which the mirrors are installed.

  In order to solve the above problem, it has been considered to replace a glass mirror with a resin reflection sheet (for example, see Patent Document 1). However, when used as a light reflecting film for solar power generation (hereinafter also referred to as “film mirror for solar power generation”, “film mirror”, or “mirror”), a film mirror using a resin film is a glass mirror. Compared with various deterioration factors, the problem of deterioration of reflectance and regular reflectance becomes obvious.

  For example, when the reflective film is used for solar thermal power generation, since it is directly exposed to sunlight for a long time, there is a problem that the film surface resin is deteriorated by ultraviolet rays and discolored to lower the transmittance. Therefore, Patent Document 2 proposes a technique in which a surface layer of a reflective film is provided with a layer containing a benzotriazole-based ultraviolet absorber. However, it is difficult to sufficiently suppress the deterioration of the resin film, and regular reflection is performed. It is not enough to maintain the rate over the long term.

  As another means for solving the decrease in reflectance, Patent Document 3 devises a mirror that multi-layers a reflection film itself including a resin film to a reflection layer and peels the reflection layer together. According to this technology, although the labor of redrawing when the reflective film is deteriorated can be reduced, it is necessary to make the reflective layer itself multi-layered. There was a problem that film peeling and film floating were likely to occur during handling, and the handling property, which is an advantage of the film mirror, was impaired.

JP 2005-59382 A US Patent Application Publication No. 2005/0159514 US Pat. No. 5,646,792

  The present invention has been made in view of the above-mentioned problems and situations, and the solution to the problem is a harsh environment as a light reflecting film for solar power generation (film mirror for solar power generation) while maintaining the handleability as a film mirror. Even when used under a long period of time, it is possible to maintain a high regular reflectance for a long period of time, and it is lightweight and flexible. To provide a light reflecting film for solar power generation having excellent light resistance and weather resistance, and having a good regular reflectance with respect to solar heat, a method for producing the same, and a solar power generation reflecting device using the light reflecting film for solar power generation. It is.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor mainly caused a decrease in regular reflectance due to ultraviolet rays of sunlight due to resin discoloration on the film surface and unevenness due to resin deterioration rather than deterioration of the metal reflection layer. I found out that The regular reflection function is impaired by the ultraviolet rays of sunlight by making the surface layer easily peelable without using multiple layers including the silver reflection layer as in the technique disclosed in Patent Document 2. Even in this case, it was found that the regular reflectance was recovered by peeling off the surface layer and could be used for a long time.

  Also, when using a solar power generation light reflecting film as a solar power generation reflection device, because it is exposed to the outdoor environment, sand, gravel, flying objects and, in some cases, ice collides with the film surface due to wind and rain, The film surface is often damaged, and the regular reflection function as a mirror is often impaired. In addition, it is necessary to clean the film surface to maintain the regular reflection function as a mirror, but when cleaning the surface with a mop etc., sand and minute foreign matter intervene and damage the film surface to generate irregularities And it turned out that the regular reflection function declines.

  That is, as a result of the study of the present inventors, various factors of the reflectance and regular reflectance reduction of the solar power generation light reflecting film are caused by the protective layer provided on the surface side of the reflecting layer rather than the deterioration of the reflecting layer. As a design where the surface layer is dominant and the surface layer can be easily peeled off, the transmittance is lowered by ultraviolet rays, or the surface layer damaged by an external factor is peeled off, thereby impairing the handleability as a film mirror. It was found that the regular reflectance was recovered and could be used for a long time. Therefore, these knowledge was acquired and it came to this invention.

  That is, the said subject which concerns on this invention is solved by the following means.

  1. On the resin base material, as a constituent layer, an adhesive layer, a metal reflective layer, and a solar reflective film light reflecting film provided with two or more protective layers on the light source side from the metal reflective layer, A light reflecting film for solar power generation, wherein at least one layer is peelable.

  2. The light reflecting film for solar thermal power generation according to item 1, wherein each of the two or more protective layers contains an ultraviolet absorber.

  3. The light reflecting film for solar power generation according to the above item 1 or 2, wherein at least one layer of the peelable protective layer contains an acrylate resin.

  4). The said reflective layer contains inorganic oxide particle | grains, The light reflection film for solar thermal power generation as described in any one of said 1st term | claim characterized by the above-mentioned.

  5. The light reflecting film for solar thermal power generation according to any one of Items 1 to 4, wherein a main component of the metal constituting the metal reflecting layer is silver.

  6). It is a manufacturing method of the light reflective film for solar power generation which manufactures the light reflective film for solar power generation as described in any one of said 1st term | claim-5th, Comprising: The said metal reflective layer is formed by vapor deposition of a metal. The manufacturing method of the light reflection film for solar power generation characterized by having a process.

  7). It is a solar power generation reflective apparatus using the solar power generation light reflecting film according to any one of the first to fifth aspects, the side having the metal reflective layer with the resin base material in between. A solar power generation reflecting device, which is formed by attaching a solar power generation light reflecting film on a metal base material through an adhesive layer coated on the opposite resin base material surface.

  8). The solar power generation reflecting device according to claim 7, wherein the solar power generation reflecting device is a mirror structure of a heliostat for tower solar power generation.

  By the above means of the present invention, it is possible to maintain a high regular reflectance for a long time even when used as a light reflecting film for solar power generation (film mirror for solar power generation) in a harsh environment for a long time. A light-reflective film for solar thermal power generation that is light and flexible, has excellent light resistance and weather resistance, and has a good regular reflectance with respect to solar heat, which can reduce the manufacturing cost and increase the area and mass production A manufacturing method thereof can be provided. Moreover, the solar power generation reflective apparatus using the said solar power generation light reflection film can be provided.

  That is, according to the present invention, the film surface can be easily peeled off even if the film surface is yellowed, clouded, or uneven due to the ultraviolet rays of sunlight or the impact of foreign matter, and the function of regular reflectance is impaired. It can be used to restore the regular reflectivity function and extend the life of the film.

  The light reflecting film for solar power generation of the present invention is for solar power generation in which two or more protective layers are provided on the resin substrate as a constituent layer on the light source side from an adhesive layer, a metal reflecting layer, and the metal reflecting layer. A light reflecting film, wherein at least one of the protective layers is peelable. This feature is a technical feature common to the inventions according to claims 1 to 8.

  As an embodiment of the present invention, it is preferable that each of the two or more protective layers contains an ultraviolet absorber from the viewpoint of manifesting the effects of the present invention. Moreover, it is preferable that at least one layer of the peelable protective layer contains an acrylate resin. Furthermore, it is preferable that the protective layer contains inorganic oxide particles.

  In the present invention, it is preferable that the main component of the metal constituting the metal reflective layer is silver.

  As a manufacturing method of the light reflection film for solar power generation of this invention, it is preferable that it is a manufacturing method of the aspect which has the process of forming the said metal reflective layer by vapor deposition of a metal.

  The light reflecting film for solar power generation of the present invention can be suitably used for a solar power generation reflecting device. For example, a light reflecting film for solar power generation is attached on a metal substrate through an adhesive layer coated on the resin substrate surface opposite to the side having the metal reflection layer with the resin substrate interposed therebetween. It is preferable that it is a solar power generation reflective apparatus of the aspect formed. In this case, the solar power generation reflecting device is preferably a mirror structure of a heliostat for tower solar power generation.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

(Summary of configuration of light reflecting film for solar thermal power generation)
On the resin base material, as a constituent layer, an adhesive layer, a metal reflective layer, and a solar reflective film light reflecting film provided with two or more protective layers on the light source side from the metal reflective layer, At least one layer is peelable. In the present invention, in addition to the adhesive layer, the metal reflective layer, and the protective layer, a metal corrosion prevention layer and other various functional layers may be provided depending on the purpose.

(Protective layer)
The protective layer according to the present invention has a laminated structure of at least two layers and is provided for preventing scratches. In the present invention, at least one of the protective layers is peelable.

  The protective layer closest to the metal reflective layer does not need to be easily peeled off, but the protective layer placed on the sunlight incident side from the protective layer is placed so that it can be easily peeled off. When the outermost protective layer is deteriorated by ultraviolet rays or by scratches, the performance can be maintained for a long time by peeling the deteriorated protective layer and making the inner intact protective layer a resurface layer.

  In addition, in order to make at least one layer of the protective layer peelable, at least one layer of the protective layer is provided with an “easily peelable adhesive layer” described later.

  The protective layer can be composed of an acrylic resin, a urethane resin, a melamine resin, an epoxy resin, an organic silicate compound, a silicone resin, or the like. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability. Further, from the viewpoint of curability, flexibility, and productivity, an active energy ray-curable acrylic resin or a thermosetting acrylic resin is also preferably used. In addition, it is preferable that an acrylic resin containing a rubber polymerization component having a glass transition temperature Tg of room temperature or lower is excellent in impact resistance.

  The active energy ray-curable acrylic resin or thermosetting acrylic resin is a composition containing a polyfunctional acrylate, an acrylic oligomer, or a reactive diluent as a polymerization curing component. In addition, you may use what contains a photoinitiator, a photosensitizer, a thermal-polymerization initiator, a modifier, etc. as needed.

  Acrylic oligomers include polyester acrylates, urethane acrylates, epoxy acrylates, polyether acrylates, etc., including those in which a reactive acrylic group is bonded to an acrylic resin skeleton, and rigid materials such as melamine and isocyanuric acid. A structure in which an acrylic group is bonded to a simple skeleton can also be used.

  In addition, the reactive diluent has a function of a solvent in the coating process as a medium of the coating agent, and has a group that itself reacts with a monofunctional or polyfunctional acrylic oligomer. It becomes a copolymerization component.

  Commercially available polyfunctional acrylic cured paints include Mitsubishi Rayon Co., Ltd. (trade name “Diabeam (registered trademark)” series, etc.), Nagase Sangyo Co., Ltd. (trade name “Denacol (registered trademark)” series, etc. ), Shin-Nakamura Co., Ltd .; (trade name “NK Ester” series, etc.), DIC Corporation; (trade name “UNIDIC (registered trademark)” series, etc.), Toagosei Co., Ltd .; ("Series etc."), Nippon Oil & Fats Co., Ltd .; (trade name "Blemmer (registered trademark)" series, etc.), Nippon Kayaku Co., Ltd .; (trade name "KAYARAD (registered trademark)" series, etc.), Kyoeisha Chemical Co., Ltd .; Products such as “light ester” series, “light acrylate” series, etc.) can be used.

  Also coated with plastic films such as thermoplastic acrylic film, polycarbonate film, polyarylate film, polyethylene naphthalate film, polyethylene terephthalate film, fluorine film, or resin kneaded with titanium oxide, silica, aluminum powder, copper powder, etc. In addition, a resin film subjected to surface processing such as metal vapor deposition is also used. It is preferable to use an acrylic film. The thickness of the film is not particularly limited but is usually preferably in the range of 10 to 125 μm.

  In the present invention, various additives can be further blended in the protective layer as required, as long as the effects of the present invention are not impaired. For example, stabilizers such as antioxidants and light stabilizers, surfactants, leveling agents and antistatic agents can be used. In particular, it is preferable to contain an ultraviolet absorber in order to protect the reflective layer of resin, silver or the like from the ultraviolet rays of sunlight, and it is more preferred to contain it in the entire protective layer. The leveling agent is effective in reducing surface irregularities, particularly when the functional layer is applied. As a leveling agent, for example, a dimethylpolysiloxane-polyoxyalkylene copolymer (for example, SH190 manufactured by Toray Dow Corning Co., Ltd.) is suitable as a silicone leveling agent.

(Adhesive layer for easy peeling)
The easily peelable adhesive layer according to the present invention can be selected from a pressure-sensitive adhesive called a re-peeling type and a material called a re-peeling / reattaching type, but any adhesive material having a re-peelable function should be used. Can do.

  The material constituting the adhesive layer can be selected from, for example, natural rubber, synthetic rubber, acrylic resin and silicone resin, polyolefin resin, polyvinyl ether resin, urethane resin, etc., but acrylic resin, Polyolefin and silicone resins are preferably used. An emulsion system in which an adhesive component is dispersed in water can also be used, but an organic solvent system is preferably used from the viewpoint of transparency and reduction of the remaining adhesive.

  Specific examples include, but are not limited to, single acrylates such as methyl acrylate, acrylic acid, ethyl acrylate, butyl acrylate, propyl acrylate, butyl methacrylate, acrylonitrile, hydroxyethyl acrylate, isononyl acrylate, and stearyl acrylate. Examples thereof include a copolymer or a copolymer. Specific examples of the polyvinyl ether resin system include polyvinyl ether and polyvinyl isobutyl ether. In specific examples of silicone, dimethylpolysiloxane, fluorosilicone and the like can be used. In addition, commercially available products of F5M, F6Q, and F2F manufactured by Oji Tac Co., Ltd. can be used as the acrylic type.

  The thickness of the adhesive layer is preferably from 0.01 to 5 μm, more preferably from 0.1 to 2.0 μm, from the viewpoints of adhesion, smoothness, reflectance of the reflecting material, and the like.

  As a method for forming the adhesive layer, conventionally known coating methods such as gravure coating method, reverse coating method, die coating method, blade coater, roll coater, air knife coater, screen coater, bar coater and curtain coater can be used.

  In addition, by providing a peelable brittle layer as in the technique described in Japanese Patent Application Laid-Open No. 2002-348551 between the protective layer and the easily peelable adhesive layer, it is difficult for the adhesive to remain on the film after peeling. It is also preferable to make it.

(UV absorber)
In the present invention, an ultraviolet absorber can be added for the purpose of preventing deterioration due to sunlight or ultraviolet rays. Each of the two or more protective layers preferably contains an ultraviolet absorber. Moreover, it is also preferable that at least any one layer other than the protective layer among the constituent layers provided on the resin base material contains an ultraviolet absorber.

  Examples of the ultraviolet absorber include benzophenone, benzotriazole, phenyl salicylate, and triazine.

  Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxy-benzophenone, 2-hydroxy-4-methoxy-benzophenone, 2-hydroxy-4-n-octoxy-benzophenone, 2-hydroxy-4-dodecyloxy-benzophenone, 2- Hydroxy-4-octadecyloxy-benzophenone, 2,2′-dihydroxy-4-methoxy-benzophenone, 2,2′-dihydroxy-4,4′-dimethoxy-benzophenone, 2,2 ′, 4,4′-tetra And hydroxy-benzophenone.

  Examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) benzotriazole, 2 -(2'-hydroxy-3'-t-butyl-5'-methylphenyl) benzotriazole and the like.

  Examples of the phenyl salicylate ultraviolet absorber include phenylsulcylate, 2-4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, and the like. Examples of hindered amine ultraviolet absorbers include bis (2,2,6,6-tetramethylpiperidin-4-yl) sebacate.

  Examples of triazine ultraviolet absorbers include 2,4-diphenyl-6- (2-hydroxy-4-methoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-). Ethoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-propoxyphenyl) -1,3,5-triazine, 2,4-diphenyl- (2-hydroxy-4-) Butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-butoxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2- Hydroxy-4-hexyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-octyloxyphenyl) -1,3,5-triazi 2,4-diphenyl-6- (2-hydroxy-4-dodecyloxyphenyl) -1,3,5-triazine, 2,4-diphenyl-6- (2-hydroxy-4-benzyloxyphenyl) -1 , 3,5-triazine and the like.

  In addition to the above, the ultraviolet absorber includes a compound having a function of converting the energy held by ultraviolet rays into vibrational energy in the molecule and releasing the vibrational energy as thermal energy or the like. Furthermore, those that exhibit an effect when used in combination with an antioxidant, a colorant, or the like, or a light stabilizer that acts as a light energy conversion agent, called a quencher, can be used in combination. However, when using the above-mentioned ultraviolet absorber, it is necessary to select one in which the light absorption wavelength of the ultraviolet absorber does not overlap with the effective wavelength of the photopolymerization initiator.

  In the case of using a normal ultraviolet ray inhibitor, it is effective to use a photopolymerization initiator that generates radicals with visible light.

  The usage-amount of a ultraviolet absorber is 0.1-20 mass%, Preferably it is 1-15 mass%, More preferably, it is 3-10 mass%. When it is more than 20% by mass, the adhesion is deteriorated, and when it is less than 0.1% by mass, the effect of improving weather resistance is small.

(Resin base material)
Various conventionally known resin films can be used as the resin base material according to the present invention. For example, cellulose ester film, polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene terephthalate, polyethylene naphthalate polyester film, polyethylene film, polypropylene film, cellophane, Cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, polycarbonate film, cycloolefin resin Film, polymethylpente It is a film, a polyether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, and acrylic films. Among these, acrylate films and cycloolefin resin films are preferably used. Even a film manufactured by melt casting film formation may be a film manufactured by solution casting film formation.

  The thickness of the resin base material is preferably an appropriate thickness according to the type and purpose of the resin. For example, it is generally in the range of 10 to 300 μm. Preferably it is 20-200 micrometers, More preferably, it is 30-100 micrometers.

(Adhesive layer)
The adhesive layer according to the present invention is not particularly limited as long as it has a function of improving the adhesion between the metal reflective layer and the resin base material (resin film), but is preferably made of a resin. Therefore, the adhesive layer has an adhesive property for closely adhering the resin base material (resin film) and the metal reflective layer, heat resistance that can withstand heat when the metal reflective layer is formed by a vacuum deposition method, and the metal reflective layer. Smoothness is required to bring out the high reflection performance inherent in

  The resin used as the binder for the adhesive layer is not particularly limited as long as it satisfies the above conditions of adhesion, heat resistance, and smoothness, and polyester resin, acrylate resin, melamine resin, epoxy Resin, polyamide resin, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin, etc. can be used singly or as a mixed resin. From the point of weather resistance, acrylate resin, polyester resin and melamine resin are mixed. A resin is preferable, and a thermosetting resin in which a curing agent such as isocyanate is further mixed is more preferable.

  In the present invention, it is particularly preferable to use an acrylate tree. Specific examples include polyacrylates and polymethacrylates such as poly (methyl methacrylate) (“PMMA”).

  The thickness of the adhesive layer is preferably 0.01 to 3 μm, more preferably 0.1 to 1 μm, from the viewpoints of adhesion, smoothness, reflectance of the reflecting material, and the like.

  As a method for forming the adhesive layer, conventionally known coating methods such as a gravure coating method, a reverse coating method, and a die coating method can be used.

(Metal reflective layer)
The metal reflective layer according to the present invention is a layer made of a metal or the like having a function of reflecting sunlight. The surface reflectance of the metal reflective layer is preferably 80% or more, more preferably 90% or more. The metal reflective layer is preferably formed of a material containing any element selected from the element group consisting of Al, Ag, Cr, Cu, Ni, Ti, Mg, Rh, Pt, and Au.

  Among them, it is preferable that Al or Ag is a main component from the viewpoint of reflectance and corrosion resistance, and two or more such metal thin films may be formed. In the present invention, it is particularly preferable to use a silver reflective layer mainly composed of silver.

Further, a layer made of a metal oxide such as SiO ₂ or TiO ₂ may be provided in this order on the metal reflective layer to further improve the reflectance.

  For example, as a method for forming a metal reflective layer (for example, a silver reflective layer) according to the present invention, either a wet method or a dry method can be used.

  The wet method is a general term for a plating method, and is a method of forming a film by depositing a metal from a solution. Specific examples include silver mirror reaction.

  On the other hand, the dry method is a general term for a vacuum film-forming method. Specific examples include a resistance heating vacuum deposition method, an electron beam heating vacuum deposition method, an ion plating method, and an ion beam assisted vacuum deposition method. And sputtering method. In particular, a vapor deposition method capable of a roll-to-roll method for continuously forming a film is preferably used in the present invention. That is, as a method for producing a solar power generation light reflecting film for producing the solar power generation light reflecting film of the present invention, production of an embodiment having a step of forming the metal reflecting layer (silver reflecting layer) by metal (silver) deposition. A method is preferred.

  The thickness of the metal (silver) reflective layer is preferably 10 to 200 nm, more preferably 30 to 150 nm, from the viewpoint of reflectivity and the like.

  In the present invention, the metal (silver) reflective layer may be on the light incident side or on the opposite side with respect to the support.

(Metal corrosion prevention layer)
In the present invention, the metal corrosion prevention layer is provided adjacent to the metal reflection layer, contains a corrosion inhibitor, prevents corrosion of the metal of the metal reflection layer, and contributes to prevention of scratches on the metal reflection layer. is there.

  The resin used as the binder for the metal corrosion prevention layer can be a polyester resin, an acrylic resin, a melamine resin, an epoxy resin, or a mixture of these resins. From the viewpoint of weather resistance, a polyester resin, Acrylic resins are preferred, and more preferably thermosetting resins mixed with a curing agent such as isocyanate.

  As the isocyanate, various conventionally used isocyanates such as TDI (tolylene diisocyanate), XDI (xylene diisocyanate), MDI (methylene diisocyanate), and HMDI (hexamethylene diisocyanate) can be used. From the viewpoint of properties, XDI, MDI, and HMDI isocyanates are preferably used.

  The thickness of the metal corrosion prevention layer is preferably from 0.01 to 3 μm, more preferably from 0.1 to 1 μm, from the viewpoints of adhesion, weather resistance and the like.

  As a method for forming the metal corrosion prevention layer, conventionally known coating methods such as a gravure coating method, a reverse coating method, and a die coating method can be used.

(Corrosion inhibitor)
The corrosion inhibitor for the metal reflective layer used in the light reflecting film for solar power generation of the present invention is roughly classified into a corrosion inhibitor and an antioxidant having an adsorbing group for a metal.

  Here, “corrosion” refers to a phenomenon in which a metal (silver) is chemically or electrochemically eroded or deteriorated by an environmental material surrounding it (see JIS Z0103-2004).

  It is preferable that the light reflecting film for solar power generation of the present invention is an embodiment in which the adhesive layer contains an antioxidant and the upper adjacent layer contains a corrosion inhibitor having an adsorbing group for a metal.

The content of the corrosion inhibitor varies depending on the compound used, but is generally preferably in the range of 0.1 to 1.0 g / m ² .

<Corrosion inhibitor with adsorptive group for metal>
Corrosion inhibitors having an adsorptive group for metals include amines and derivatives thereof, compounds having a pyrrole ring, compounds having a triazole ring, compounds having a pyrazole ring, compounds having a thiazole ring, compounds having an imidazole ring, indazole Desirably, the compound is selected from a compound having a ring, copper chelate compounds, thioureas, a compound having a mercapto group, at least one naphthalene-based compound, or a mixture thereof.

  Examples of amines and derivatives thereof include ethylamine, laurylamine, tri-n-butylamine, O-toluidine, diphenylamine, ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, monoethanolamine, diethanolamine, triethanolamine, 2N- Dimethylethanolamine, 2-amino-2-methyl-1,3-propanediol, acetamide, acrylamide, benzamide, p-ethoxychrysidine, dicyclohexylammonium nitrite, dicyclohexylammonium salicylate, monoethanolaminebenzoate, dicyclohexylammonium benzoate, diisopropyl Ammonium benzoate, diisopropylammonium nitrite, Black hexylamine carbamate, nitronaphthalene nitrite, cyclohexylamine benzoate, dicyclohexylammonium cyclohexanecarboxylate, cyclohexylamine cyclohexane carboxylate, dicyclohexylammonium acrylate, cyclohexylamine acrylate, or mixtures thereof.

  Examples of the compound having a pyrrole ring include N-butyl-2,5-dimethylpyrrole, N-phenyl-2,5-dimethylpyrrole, N-phenyl-3-formyl-2,5-dimethylpyrrole, and N-phenyl-3. , 4-diformyl-2,5-dimethylpyrrole, or a mixture thereof.

  Examples of the compound having a triazole ring include 1,2,3-triazole, 1,2,4-triazole, 3-mercapto-1,2,4-triazole, 3-hydroxy-1,2,4-triazole, 3- Methyl-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-methyl-3-mercapto-1,2,4-triazole, 4-methyl-1,2,3-triazole, Benzotriazole, tolyltriazole, 1-hydroxybenzotriazole, 4,5,6,7-tetrahydrotriazole, 3-amino-1,2,4-triazole, 3-amino-5-methyl-1,2,4- Triazole, carboxybenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy 5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-4-octoxyphenyl) benzo A triazole etc. or these mixtures are mentioned.

  Examples of the compound having a pyrazole ring include pyrazole, pyrazoline, pyrazolone, pyrazolidine, pyrazolidone, 3,5-dimethylpyrazole, 3-methyl-5-hydroxypyrazole, 4-aminopyrazole, and a mixture thereof.

  Examples of the compound having a thiazole ring include thiazole, thiazoline, thiazolone, thiazolidine, thiazolidone, isothiazole, benzothiazole, 2-N, N-diethylthiobenzothiazole, P-dimethylaminobenzallodanine, 2-mercaptobenzothiazole and the like. Or a mixture thereof.

  Examples of the compound having an imidazole ring include imidazole, histidine, 2-heptadecylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-undecylimidazole, 1-benzyl-2-methyl. Imidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2-undecyl Imidazole, 2-phenyl-4-methyl-5-hydromethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 4-formylimidazole, 2-methyl-4-formylimidazole, 2-phenyl-4- Formylimidazole, 4-methyl-5-formylimidazole, 2-ethyl-4-methyl-5-formylimidazole, 2-phenyl-4-methyl-4-formylimidazole, 2-mercaptobenzimidazole, etc., or These mixtures are mentioned.

  Examples of the compound having an indazole ring include 4-chloroindazole, 4-nitroindazole, 5-nitroindazole, 4-chloro-5-nitroindazole, and a mixture thereof.

  Examples of the copper chelate compounds include acetylacetone copper, ethylenediamine copper, phthalocyanine copper, ethylenediaminetetraacetate copper, hydroxyquinoline copper, and a mixture thereof.

  Examples of thioureas include thiourea, guanylthiourea, and the like, or a mixture thereof.

  As the compound having a mercapto group, mercaptoacetic acid, thiophenol, 1,2-ethanediol, 3-mercapto-1,2,4-triazole, 1-methyl-3-mercapto can be used by adding the above-described materials. -1,2,4-triazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, glycol dimercaptoacetate, 3-mercaptopropyltrimethoxysilane, and the like, or a mixture thereof.

  Examples of the naphthalene type include thionalide.

<Antioxidant>
An antioxidant can also be used as the corrosion inhibitor for the metal reflective layer used in the light reflecting film for solar power generation of the present invention.

  As the antioxidant, it is preferable to use a phenol-based antioxidant, a thiol-based antioxidant, and a phosphite-based antioxidant.

  Examples of the phenolic antioxidant include 1,1,3-tris (2-methyl-4-hydroxy-5-t-butylphenyl) butane and 2,2′-methylenebis (4-ethyl-6-t-). Butylphenol), tetrakis- [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, 2,6-di-t-butyl-p-cresol, 4,4 '-Thiobis (3-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-6-tert-butylphenol), 1,3,5-tris (3', 5'-di-t -Butyl-4'-hydroxybenzyl) -S-triazine-2,4,6- (1H, 3H, 5H) trione, stearyl-β- (3,5-di-t-butyl-4-hydroxyphenyl) propio Triethyl glycol bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 3,9-bis [1,1-di-methyl-2- [β- (3 -T-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl] -2,4,8,10-tetraoxoxaspiro [5,5] undecane, 1,3,5-trimethyl-2,4 , 6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and the like. In particular, the phenolic antioxidant preferably has a molecular weight of 550 or more.

  Examples of the thiol antioxidant include distearyl-3,3′-thiodipropionate and pentaerythritol-tetrakis- (β-lauryl-thiopropionate).

  Examples of the phosphite antioxidant include tris (2,4-di-t-butylphenyl) phosphite, distearyl pentaerythritol diphosphite, di (2,6-di-t-butylphenyl) pentaerythritol. Diphosphite, bis- (2,6-di-t-butyl-4-methylphenyl) -pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) 4,4'-biphenylene-diphosphonite 2,2'-methylenebis (4,6-di-t-butylphenyl) octyl phosphite.

  In the present invention, the above antioxidant and the following light stabilizer can be used in combination.

  Examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, Bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate, 1-methyl- 8- (1,2,2,6,6-pentamethyl-4-piperidyl) -sebacate, 1- [2- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] ethyl ] -4- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6 6-tetramethyl Piperidine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butane-tetracarboxylate, triethylenediamine, 8-acetyl-3-dodecyl-7,7,9 , 9-tetramethyl-1,3,8-triazaspiro [4,5] decane-2,4-dione.

  In addition, [2,2′-thiobis (4-t-octylphenolate)]-2-ethylhexylamine nickel (II), nickel complex-3,5-di-t-butyl-4 as a nickel-based UV stabilizer -Hydroxybenzyl phosphate monoethylate, nickel dibutyl dithiocarbamate, etc. can also be used.

  In particular, the hindered amine light stabilizer is preferably a hindered amine light stabilizer containing only a tertiary amine, specifically, bis (1,2,2,6,6-pentamethyl-4-piperidyl). Sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) -2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonate, or A condensate of 1,2,2,6,6-pentamethyl-4-piperidinol / tridecyl alcohol and 1,2,3,4-butanetetracarboxylic acid is preferred.

(Gas barrier layer)
It is also preferable to provide a gas barrier layer in the present invention. This is to prevent deterioration of the humidity, in particular, deterioration of the resin base material and various functional elements protected by the resin base material due to high humidity.

The moisture barrier property of the gas barrier layer is preferably adjusted so that the water vapor permeability at 40 ° C. and 90% RH is preferably 1 g / m ² · day / μm or less. The gas barrier layer according to the present invention is not particularly limited in its formation method, but an inorganic film layer may be formed by vapor deposition. After coating the ceramic precursor of the inorganic oxide film, the coating film is heated and / or Alternatively, it is also preferable to form an inorganic oxide film by ultraviolet irradiation.

<Ceramic precursor>
The gas barrier layer according to the present invention can be formed by applying a general heating method after applying a ceramic precursor that forms an inorganic oxide film by heating, but is preferably formed by local heating. The ceramic precursor is preferably a sol-like organometallic compound or polysilazane.

<Inorganic oxide>
The protective layer of the present invention can preferably contain an inorganic oxide. Silicon (Si), Aluminum (Al), Zirconium (Zr), Titanium (Ti), Tantalum (Ta), Zinc (Zn), Barium (Ba), Indium (In), Tin (Sn), Niobium (Nb), etc. It is characterized by being an oxide of the element.

  For example, silicon oxide, aluminum oxide, zirconium oxide and the like. Of these, silicon oxide is preferable, and particles having an average particle diameter of less than 50 nm are preferably used.

(Thickness of the entire light reflecting film for solar power generation)
The total thickness of the solar reflective film for solar power generation according to the present invention is preferably from 75 to 250 μm, more preferably from 90 to 230 μm, and even more preferably from 100 to 250 μm from the viewpoints of mirror deflection prevention, regular reflectance, handling properties, and the like. 220 μm.

(Reflector for solar thermal power generation)
The light reflecting film for solar power generation of the present invention can be preferably used for the purpose of concentrating sunlight. The light reflecting film for solar power generation can be used alone as a solar light collecting mirror, but more preferably, the adhesive coated on the surface of the resin base opposite to the side having the metal reflective layer across the resin base. The light reflecting film for solar power generation is stuck on another base material, particularly on a metal base material, through a layer, and used as a solar power generation reflecting device.

  When used as a solar power generation reflecting device, the reflecting device is shaped like a bowl (semi-cylindrical), and a cylindrical member having fluid inside is provided at the center of the semicircle, and sunlight is condensed on the cylindrical member. The form (for example, trough type solar thermal power generation) which heats an internal fluid and converts the thermal energy and generates electric power is mentioned as one form. In addition, flat reflectors were installed at multiple locations, and the sunlight reflected by each reflector was collected on one reflector (central reflector) and reflected by the reflector. The form (for example, tower type solar power generation) which generates electric power by converting thermal energy in a power generation part is also mentioned as one form. In particular, in the latter form, since a high regular reflectance is required for the reflection device (mirror structure of the heliostat) used, the light reflecting film for solar power generation of the present invention is particularly preferably used.

<Adhesive layer>
The adhesive layer is not particularly limited, and for example, any of a dry laminating agent, a wet laminating agent, an adhesive, a heat seal agent, a hot melt agent, and the like is used.

  For example, polyester resin, urethane resin, polyvinyl acetate resin, acrylic resin, nitrile rubber, etc. are used.

  The laminating method is not particularly limited, and for example, it is preferable to carry out continuously by a roll method from the viewpoint of economy and productivity.

  The thickness of the pressure-sensitive adhesive layer is usually preferably in the range of about 1 to 50 μm from the viewpoints of the pressure-sensitive adhesive effect, the drying speed, and the like.

  The other base material to be bonded to the solar power generation light reflecting film of the present invention, which is appropriately adopted in the present invention, may be any material that can impart the protective property of the metal reflective layer, for example, an acrylic film or sheet, polycarbonate Film or sheet, polyarylate film or sheet, polyethylene naphthalate film or sheet, polyethylene terephthalate film or sheet, plastic film or sheet such as fluorine film, or resin film kneaded with titanium oxide, silica, aluminum powder, copper powder, etc. Alternatively, a sheet or a resin film or sheet coated with a resin kneaded with these or subjected to surface processing such as metal deposition is used.

  Although there is no restriction | limiting in particular in the thickness of a bonding film or sheet, Usually, it is preferable that it is the range of 12-250 micrometers.

  In addition, these other base materials may be bonded together after being provided with recesses or protrusions before being bonded to the solar power generation light reflecting film of the present invention, and after bonding, they are formed to have recesses or protrusions. Alternatively, the bonding and the molding so as to have a concave portion or a convex portion may be performed at the same time.

<Metal base material>
The metal substrate of the solar collector mirror according to the present invention includes a steel plate, a copper plate, an aluminum plate, an aluminum plated steel plate, an aluminum alloy plated steel plate, a copper plated steel plate, a tin plated steel plate, a chrome plated steel plate, a stainless steel plate, etc. A metal material having a high rate can be used.

  In the present invention, it is particularly preferable to use a plated steel plate, a stainless steel plate, an aluminum plate, or the like having good corrosion resistance.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

[Production of film mirror]
Below, the preparation methods of the film mirror using the light reflection film for solar power generation of this invention and the film mirror as a comparative example are demonstrated.

(Preparation of film mirror 1)
When forming a thermoplastic polymethyl methacrylate resin film (weight average molecular weight 100,000, number average molecular weight 50000; hereinafter simply referred to as “acrylic film”), an ultraviolet absorber (Comparative Compound 1, TINUVIN 928, manufactured by BASF Japan Ltd.) is acrylic. A resin base film (film A) that was used as a first protective layer having a thickness of 50 μm was prepared by containing 5% by mass in the film.

  On this film, F5M manufactured by Oji Tac Co., Ltd. was applied with a thickness of 1 μm as an easily peelable adhesive layer, and film A serving as a second protective layer was laminated and adhered to produce film B.

  Further, a third protective layer was installed on the film B in the same manner as the second protective layer to produce a film C.

  On this film C, polyester resin (Polyester SP-181, manufactured by Nippon Synthetic Chemical Co., Ltd.), melamine resin (Super Becamine J-820, manufactured by DIC), TDI isocyanate (2,4-tolylene diisocyanate), HDMI-based isocyanate (1,6-hexamethylene diisocyanate) was adjusted to a resin solid content ratio of 20: 1: 1: 2 and a solid content concentration of 10% by mass, and an antioxidant (1,2,2'-methylenebis) was added. (4,6-di-t-butylphenyl) octyl phosphite) is added in an amount of 0.3% by mass to the in-layer resin, and the resin mixed in toluene is coated by a gravure coating method to a thickness of 0.1 μm. A metal corrosion prevention layer was formed. A silver reflection layer having a thickness of 80 nm was formed as a metal reflection layer on the metal corrosion prevention layer by vacuum deposition. Gravure coating a resin in which polyester resin and TDI (tolylene diisocyanate) isocyanate are mixed at a resin solid content ratio of 10: 2 on the silver reflection layer as an adjacent layer far from the light incident side of the silver reflection layer The film mirror 1 of this invention was produced by coating by the method to form a layer having a thickness of 0.1 μm.

(Preparation of film mirror 2)
In the production of the film mirror 1, a film mirror produced in the same manner as the film mirror 1 is used as the film of the present invention except that the acrylic film of the first protective layer on the incident light side and the easily peelable adhesive layer thereunder are not provided. A mirror 2 was produced.

(Preparation of film mirror 3)
The film mirror 3 of the present invention was prepared in the same manner as the film mirror 2 except that 3% by mass of silica oxide particles having an average particle diameter of 20 nm were contained in each protective layer in the production of the film mirror 2.

(Preparation of film mirror 4)
In the production of the film mirror 2, a film mirror 4 produced in the same manner as the film mirror 2 was used except that the acrylic film of the protective layer located on the outermost surface was replaced with a polyethylene terephthalate (PET) film.

(Preparation of film mirror 5)
In the production of the film mirror 2, a film mirror produced in the same manner as the film mirror 2 was compared except that the acrylic film of the second protective layer on the incident light side resurface and the easily peelable adhesive layer thereunder were not provided. A film mirror 5 was produced.

[Preparation of solar power generation reflector]
The film mirrors 1 to 5 are pasted on a stainless steel (SUS304) plate with a thickness of 0.1 mm and a length of 4 cm and a width of 5 cm, with an acrylic film surface as the top, and an adhesive layer with a thickness of 3 μm. The solar thermal power generation reflectors 1 to 5 were produced.

  Table 1 shows the contents of film mirrors 1 to 5 (Examples 1 to 4 and Comparative Example 5).

[Evaluation of reflector for solar thermal power generation]
About the film mirror of the reflector for solar power generation obtained above, the regular reflectance, the moisture-light resistance test, and the scratch resistance evaluation were performed by the following methods.

(Regular reflectance)
A spectrophotometer “UV265” manufactured by Shimadzu Corporation was modified with an integrating sphere reflection accessory, and the incident angle of incident light was adjusted to 5 ° with respect to the normal of the reflecting surface. The regular reflectance at a reflection angle of 5 ° was measured. Evaluation was measured as an average reflectance of 350 to 700 nm.

(Test A: Moisture-resistant light test)
After standing for 10 days under the conditions of 85 ° C. and 85% RH, ultraviolet irradiation was performed for 5 days in an environment of 65 ° C. using an I-Super UV tester manufactured by Iwasaki Electric. After these tests were repeated three times, the regular reflectance was measured by the same method as the light reflectance measurement. The reduction rate of the regular reflectance of the film mirror before and after the forced deterioration test was calculated and evaluated according to the following criteria. After the evaluation, the product of the present invention from which the first protective layer can be peeled is peeled off from the first protective layer and evaluated for regular reflectance. After that, the second test A was conducted. After the evaluation, the product of the present invention from which the second protective layer can be peeled is peeled off the second protective layer and evaluated for regular reflectance. Thereafter, a third test A was performed and evaluated in the same manner.
5: The rate of decrease in regular reflectance is less than 5% 4: The rate of decrease in regular reflectance is 5% or more and less than 10% 3: The rate of decrease in regular reflectance is 10% or more but less than 15% 2: The rate of decrease in regular reflectance 15% or more and less than 20% 1: The rate of decrease in regular reflectance is 20% or more (Test B: Moisture resistance test)
Using a blasting machine manufactured by Fuji Seisakusho (model SGK-6DT), # 60 glass beads (particle size 250 to 355 μm) at a pressure of 0.1 Pascal and consumption rate = 1100 g / hr at a distance of 150 mm. Spraying was performed for 1 minute, and a test for scratching the film resurface was conducted. After the test, the regular reflectance was measured and evaluated according to the following criteria. After the evaluation, the product of the present invention from which the first protective layer can be peeled is peeled off from the first protective layer and evaluated for regular reflectance. After that, the second test B was conducted. After the evaluation, the product of the present invention from which the second protective layer can be peeled is peeled off the second protective layer and evaluated for regular reflectance. Thereafter, a third test B was performed and evaluated in the same manner.
5: The rate of decrease in regular reflectance is less than 5% 4: The rate of decrease in regular reflectance is 5% or more and less than 10% 3: The rate of decrease in regular reflectance is 10% or more but less than 15% 2: The rate of decrease in regular reflectance 15% or more and less than 20% 1: The rate of decrease in regular reflectance is 20% or more. Tables 2 and 3 show the evaluation results.

  From the results of the continuous tests of tests A and B shown in Tables 2 and 3, the film mirror using the light reflecting film for solar power generation according to the present invention can maintain the regular reflectance at a high level for a long time. It can be seen that it can also be used for a mirror structure of a tower solar power generation heliostat requiring higher specular reflectance.

Claims (8)

  On the resin base material, as a constituent layer, an adhesive layer, a metal reflective layer, and a solar reflective film light reflecting film provided with two or more protective layers on the light source side from the metal reflective layer, A light reflecting film for solar power generation, wherein at least one layer is peelable.   The light reflecting film for solar power generation according to claim 1, wherein each of the two or more protective layers contains an ultraviolet absorber.   The light reflecting film for solar thermal power generation according to claim 1 or 2, wherein at least one of the peelable protective layers contains an acrylate-based resin.   The said protective layer contains inorganic oxide particle, The light reflection film for solar thermal power generation as described in any one of Claim 1- Claim 3 characterized by the above-mentioned.   The light reflecting film for solar power generation according to any one of claims 1 to 4, wherein a main component of the metal constituting the metal reflecting layer is silver.   It is a manufacturing method of the light reflection film for solar power generation which manufactures the light reflection film for solar power generation as described in any one of Claim 1- Claim 5, Comprising: The process of forming the said metal reflection layer by vapor deposition of metal. The manufacturing method of the light reflection film for solar power generation characterized by having.   It is a reflective apparatus for solar thermal power generation using the light reflective film for solar thermal power generation as described in any one of Claim 1- Claim 5, Comprising: Opposite to the side which has the said metal reflective layer on both sides of the said resin base material A solar power generation reflecting device, which is formed by attaching a light reflecting film for solar power generation on a metal base material through an adhesive layer coated on the side resin base material surface.   The solar power generation reflector according to claim 7, wherein the solar power generation reflector is a mirror structure of a tower type solar power generation heliostat.