JP2012053382A - Light-reflecting film for solar power generation and reflecting device for solar power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-reflecting film for solar power generation, which can maintain high regular reflectance for a long period of time while maintaining handling property as a film mirror, even when the film as a light-reflecting film for solar power generation is used for a long period of time in a severe environment, which is lightweight and flexible, which can be mass-produced in a large area while suppressing the cost of production, and which is excellent in light resistance and weather resistance and has a good regular reflectance with respect to solar heat, and to provide a reflecting device for solar power generation using the light-reflecting film.SOLUTION: The light-reflecting film for solar power generation has a surface layer containing a copolymer comprising polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer as structural elements, at least one layer of a resin substrate and a metal reflecting layer, in an outermost surface where solar light enters.

Description

  The present invention relates to a light reflecting film for solar thermal power generation and a solar power generation reflecting device using the same.

  Natural energy such as coal energy, biomass energy, nuclear energy, wind energy, and solar energy is currently being studied as alternative energy alternatives to fossil fuel energy such as oil and natural gas. Stable and abundant 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 have high environmental durability. However, they are damaged during transportation, and because they are heavy, there is a problem that the construction cost of the plant is increased due to the strength of the frame 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 (see, for example, Patent Document 1). However, a light reflecting film for solar power generation (hereinafter also referred to as a solar power generation film mirror, film mirror, or mirror) is a process of depositing and applying a reflective layer, a protective layer, etc. while roll transporting a resin film during production. Or it laminates and manufactures by film bonding. At this time, the roll product is stored in a roll state. A generally known blocking phenomenon occurs during the manufacturing process or in the storage state in a roll product. Although it depends on the degree of blocking phenomenon, swell of the film due to blocking does not have a significant effect on the quality of normal liquid crystal light guide films and film products used for building materials, but the blocking phenomenon occurs in film mirrors. It was found that the waviness caused by the cause and the non-uniformity of the constituent layer thickness have the effect of impairing the regular light reflection function of the basic function of the film mirror.

  Further, the film mirror is used by being stretched on a rigid metal plate in order to provide rigidity. It was found that when affixed to a metal plate, the film was pressure-bonded by a roller, but the film mirror was wrinkled and bent due to the feeding force of the roller part, causing a problem in that the regular reflectance decreased.

JP 2005-59382 A

  The present invention has been made in view of the above problems, and its purpose is to stabilize the quality of regular reflectance, which is a basic function, by reducing the blocking phenomenon that occurs during film mirror production or roll product storage. An object of the present invention is to provide a light reflecting film for solar power generation that can be manufactured in a large area and mass-produced at a reduced manufacturing cost. In addition, when the film mirror is pressure-bonded to the base material in order to give rigidity, the regular reflectance, which is the basic performance, is lowered unless the roll conveyance at the time of pressure bonding is good. An object is to provide a solar power generation light reflecting film and a solar power generation reflection device using the same.

  The above object of the present invention is achieved by the following configurations.

  1. The outermost surface on the sunlight incident side has a surface layer containing a copolymer composed of polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer, one or more resin base materials, and a metal reflective layer. A light reflecting film for solar thermal power generation.

  2. 2. The light reflecting film for solar power generation as described in 1 above, wherein the polysiloxane is contained in a skeleton of a polydimethylsiloxane copolymer.

  3. 3. The light reflecting film for solar thermal power generation according to 1 or 2, wherein the polycaprolactone is contained in a skeleton of a polydimethylsiloxane copolymer.

  4). It is a solar power generation reflective apparatus using the solar power generation light reflecting film according to any one of 1 to 3, wherein the surface layer has the surface layer sandwiching the resin base material of the solar power generation light reflecting film. A solar power generation reflecting device, characterized in that it is formed by attaching a light reflecting film for solar power generation on a metal base material through an adhesive layer coated on the surface of the resin base opposite to the surface.

  The present invention reduces the blocking phenomenon that occurs in the roll state after film mirror manufacturing or after manufacturing, and stabilizes the quality of regular reflectance, which is a basic function, thereby reducing the manufacturing cost and increasing the area and mass production. It was possible to obtain a light reflecting film for solar thermal power generation. Further, a solar power generation light reflecting film capable of stably obtaining a regular reflectance, which is a basic performance even when a film mirror is pressure-bonded to a base material in order to give rigidity, and a solar power generation reflecting device using the same are obtained. I was able to.

  As a result of intensive studies by the inventor to solve the above-described problems, the roll blocking phenomenon occurs when strong adhesion occurs between films during the manufacturing process and roll product storage. In order to prevent the strong adhesion between the films, it was necessary to improve the film surface to a characteristic that the adhesion was difficult to occur. However, since the film mirror is exposed to the outdoor environment due to the characteristics of the film mirror, it is necessary to have excellent characteristics such as resistance to ultraviolet rays, humidity resistance, chemical resistance and scratch resistance contained in sunlight.

  The light reflecting film for solar power generation of the present invention has a surface layer containing a copolymer having polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer as constituent elements on the outermost surface on the sunlight incident side, and one layer It has the above-mentioned resin base material and metal reflective layer.

  As an embodiment of the present invention, it is preferable that the polysiloxane is contained in the skeleton of the polydimethylsiloxane copolymer from the viewpoint of manifesting the effects of the present invention. The polycaprolactone is preferably contained in the skeleton of the polydimethylsiloxane copolymer.

  In the present invention, the main component of the metal constituting the metal reflective layer is preferably silver, and the metal reflective layer is preferably a production method having a step of forming by metal vapor deposition. Metal silver can also be formed after apply | coating a containing complex solution on a film.

  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, for solar power generation on a metal substrate through an adhesive layer coated on the resin substrate surface opposite to the side having the surface layer across the resin substrate of the light reflecting film for solar power generation It is preferable that it is a solar power generation reflective apparatus of the aspect formed by affixing a light reflection film.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail.

(Summary of configuration of light reflecting film for solar power generation)
The light reflecting film for solar power generation of the present invention has a surface layer containing a copolymer having polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer as constituent elements on the outermost surface on the sunlight incident side, and one layer It has the above-mentioned resin base material and metal reflective layer. In the present invention, in addition to the surface layer and the metal reflection layer, an adhesive layer, a metal corrosion prevention layer, and other various functional layers may be provided according to the purpose.

(Surface layer)
The light reflecting film for solar thermal power generation of the present invention may have a surface layer containing a copolymer composed of polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer on the outermost surface on the sunlight incident side. It is a feature.

  The copolymer comprising the surface layer according to the present invention as a constituent is a composition and / or compound (hereinafter referred to as “raw material”) comprising a polydimethylsiloxane copolymer, polycaprolactone, and polysiloxane as constituents. Is cross-linked (cured).

  As a form of the composition, first, when a polydimethylsiloxane copolymer, polycaprolactone and polysiloxane are each independently a constituent of the composition, second, polycaprolactone is introduced into the skeleton. When the polydimethylsiloxane copolymer and the polysiloxane are constituents of the composition, third, the polydimethylsiloxane copolymer in which the polysiloxane is introduced into the skeleton and the polycaprolactone When it becomes a constituent component of the composition, fourthly, a polydimethylsiloxane copolymer in which polycaprolactone and polysiloxane are introduced into the skeleton may be a constituent part of the composition, and each composition is independent. Alternatively, two or more kinds can be mixed and used.

(A) Polydimethylsiloxane copolymer The polydimethylsiloxane copolymer in the present invention is a copolymer having a polydimethylsiloxane portion and a polymer chain portion of a vinyl monomer, and is a block copolymer. It may be a graft copolymer.

  The synthesis of the polydimethylsiloxane block copolymer can be performed by a living polymerization method, a polymer initiator method, a polymer chain transfer method, or the like. It is preferably carried out by the method.

  In the polymer initiator method, for example,

A block copolymer can be efficiently synthesized by copolymerizing with a vinyl monomer using a polymer azo radical polymerization initiator such as In addition, a two-stage process in which a peroxy monomer and polydimethylsiloxane having an unsaturated group are copolymerized at a low temperature to synthesize a prepolymer in which a peroxide group is introduced into a side chain, and the prepolymer is copolymerized with a vinyl monomer. Polymerization can also be performed.

  In the polymer chain transfer method, for example,

After adding HS-CH ₂ COOH, HS-CH ₂ CH ₂ COOH, etc. to a silicone oil such as a silicone compound having an SH group, the silicone compound, vinyl monomer, and A block copolymer can be synthesized by copolymerizing.

  On the other hand, for polydimethylsiloxane graft copolymers, for example,

By copolymerizing a methacrylic ester of polydimethylsiloxane and the like with a vinyl monomer, a graft copolymer can be synthesized easily and with a high yield.

  Examples of vinyl monomers used in the copolymer with polydimethylsiloxane include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, octyl acrylate, cyclohexyl acrylate, tetrahydrofurfuryl acrylate, methyl methacrylate, ethyl methacrylate, n -Butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, styrene, α-methyl styrene, acrylonitrile, methacrylonitrile, Vinyl acetate, vinyl chloride, vinylidene chloride, vinyl Vinyl chloride, vinylidene fluoride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, maleic acid, maleic anhydride, citraconic acid, acrylamide, methacrylamide, N-methylolacrylamide, N , N-dimethylacrylamide, N, N-dimethylaminoethyl methacrylate, N, N-diethylaminoethyl methacrylate, diacetone acrylamide and the like. Also, vinyl monomers having an OH group such as 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, and allyl alcohol can be used. A reaction product with acid, itaconic acid, crotonic acid, maleic acid or the like can also be used. In addition, the above illustration does not limit the present invention. This copolymer of polydimethylsiloxane reduces the brittleness of the surface layer, suppresses film breakage at the time of roll conveyance, further improves slipperiness, and exhibits the effect of obtaining high roll conveyance stability.

(B) Polycaprolactone As polycaprolactone in the present invention, for example,

Bifunctional polycaprolactone diols such as

Trifunctional polycaprolactone triols, other tetrafunctional polycaprolactone polyols, etc. can be used. When introducing polycaprolactone into the skeleton of a polydimethylsiloxane copolymer, it is preferable to use lactone-modified hydroxyethyl (meth) acrylates, for example,

And radically polymerizable polycaprolactone represented by the structural formula:

  This polycaprolactone functions to suppress the occurrence of film deflection during roll conveyance, maintain surface smoothness, and suppress a decrease in the function of regular light reflectance. Furthermore, the adhesiveness with the support film is enhanced, and generally the peeling resistance of the surface layer is enhanced.

(C) Polysiloxane Examples of the polysiloxane in the present invention include tetramethoxysilane, tetraethoxysilane, methyltrimethoxysilane, methyltoxioxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, and γ-glycidoxypropyltrimethoxy. Silane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane , Γ-methacryloxypropylmethyldimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-acryloxypropyltrimethoxysilane, γ-acryloxypropylmethyldimethoxy A partially hydrolyzed product of a silane compound having a hydrolyzable silyl group such as silane, an organosilica sol in which fine particles of silicic anhydride are stably dispersed in an organic solvent, or the above silane compound having radical polymerizability in the organosilica sol What was added can be used. In addition, the above illustration does not limit the present invention.

  Polysiloxane suppresses the blocking phenomenon, provides rigidity to the surface film layer, suppresses the occurrence of tensile deflection of the film during roll conveyance, and has the effect of maintaining regular reflectance performance. A difficult effect is obtained.

  The polydimethylsiloxane copolymer in the present invention is usually produced by solution polymerization. In this solution polymerization, aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl acetate, propyl acetate, isobutyl acetate, and butyl acetate, ethanol, isopropanol Alcohol solvents such as butanol and isobutanol are used alone or as a mixed solvent. If desired, oil-soluble polymerization initiators such as benzoyl peroxide, lauryl peroxide, cumene hydroperoxide, and azobisisobutyronitrile are used. Is used. The reaction temperature of the solution polymerization is preferably 50 to 150 ° C., and the reaction time is preferably 3 to 12 hours.

  Here, when polycaprolactone and / or polysiloxane is introduced into the skeleton of the polydimethylsiloxane copolymer, polycaprolactone and / or polysiloxane is added when polymerizing the polydimethylsiloxane copolymer. And may be copolymerized. In addition, when manufacturing the said composition, each structural component is mixed by a conventional method.

  The amount of the polydimethylsiloxane portion in the polydimethylsiloxane copolymer (including those in which polycaprolactone and / or polysiloxane is introduced into the skeleton) in the present invention is preferably 1 to 25% by mass. In particular, the content is preferably 3 to 15% by mass. The polydimethylsiloxane portion plays a role of reducing the brittleness of the surface layer, improving the slipperiness, and improving the roll conveyance stability. If the amount of the polydimethylsiloxane portion is less than 1% by mass, such an effect is not sufficiently exerted. On the other hand, if the amount of the polydimethylsiloxane portion exceeds 25% by mass, the contamination of the surface layer increases, and the light regular reflection function Will be damaged. The molecular weight of the polydimethylsiloxane portion is preferably about 2000 to 30000, and the molecular weight that is effectively oriented on the surface of the surface functional material and gives good slipperiness is particularly preferably about 7000 to 15000. .

  The amount of polycaprolactone in the present invention is 3 to 40 mass in the solid matter, whether it is introduced into the skeleton of the polydimethylsiloxane copolymer or present independently in the composition. % Is preferred. This polycaprolactone functions to suppress the occurrence of film deflection, maintain surface smoothness, and suppress a decrease in the function of optical regular reflectance. Furthermore, the adhesiveness with the support film is enhanced, and generally the peeling resistance of the surface layer is enhanced. If the amount of the polycaprolactone is less than 3% by mass, these effects are reduced, and if it exceeds 45% by mass, the soiling property is increased and the regular reflection property is also deteriorated.

  The amount of the polysiloxane in the present invention is 10 to 50 mass in the solid matter, even when it is introduced into the skeleton of the polydimethylsiloxane copolymer or when it is present independently in the composition. % Is preferred. Polysiloxane suppresses the blocking phenomenon, provides rigidity to the surface film layer, suppresses the occurrence of tensile deflection of the film during roll conveyance, and has the effect of maintaining regular reflectance performance. A difficult effect is obtained. When the amount of the polysiloxane is less than 1% by mass, such an effect is not sufficiently exerted. On the other hand, when the amount of the polysiloxane exceeds 50% by mass, the roll is liable to be twisted at the time of roll conveyance.

  The surface layer of the present invention can be obtained by curing the raw materials. At this time, the polydimethylsiloxane copolymer (including those in which polycaprolactone and / or polysiloxane is introduced into the skeleton) is urethane. Crosslinking and / or melamine crosslinking is preferred.

  To urethane-crosslink a polydimethylsiloxane copolymer, methylenebis-4-cyclohexyl isocyanate, trimethylolpropane adduct of tolylene diisocyanate, hexamethylene diisocyanate is used for the polydimethylsiloxane copolymer having an OH group. Polyisocyanates such as trimethylolpropane adduct, isophorone diisocyanate trimethylolpropane adduct, tolylene diisocyanate isocyanurate, hexamethylene diisocyanate isocyanurate, isophorone diisocyanate isocyanurate, hexamethylene diisocyanate biuret, Alternatively, a urethane cross-linking agent such as block isocyanate of the polyisocyanate is added to the raw material and cured. May be Re, dibutyltin dilaurate may optionally be added as a catalyst dibutyltin diethyl hexoate like. In the case of urethane crosslinking, room temperature drying or baking drying is possible. Usually, room temperature drying is performed for 8 hours to 1 week, and baking drying is performed at 40 to 300 ° C. for 5 seconds to 120 minutes.

  On the other hand, in order to crosslink the polydimethylsiloxane copolymer with melamine, a melamine crosslinker such as alkoxymethylolmelamine may be added to the above raw material and cured. If necessary, paratoluenesulfonic acid, trichloroacetic acid, Chlorophthalic acid or the like may be added as a catalyst. In the case of melamine crosslinking, it is preferable to perform baking and drying at 80 to 120 ° C. for 5 seconds to 60 minutes. The thickness of the surface functional layer obtained by curing the raw material is preferably about 1 to 100 μm, more preferably 5 to 50 μm.

  In the present invention, various additives can be further blended in the surface layer as needed, as long as the effects of the present invention are not impaired. For example, stabilizers such as antioxidants and light stabilizers, surfactants, leveling agents, antistatic agents, and the like 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. The leveling agent is effective in reducing surface irregularities, particularly when the functional layer is applied. As the leveling agent, for example, a dimethylpolysiloxane polyoxyalkylene copolymer (for example, SH190 manufactured by Toray Dow Corning Co., Ltd.) is suitable as the silicone leveling agent.

<Inorganic oxide>
The surface 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.

(UV absorber)
In the present invention, an ultraviolet absorber can be added for the purpose of preventing deterioration due to sunlight or ultraviolet rays.

  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 light into vibrational energy in the molecule and releasing the vibrational energy as thermal energy. 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-described ultraviolet absorber, it is necessary to select a material 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 set to 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.

  In addition, a resin film coated with a resin kneaded with titanium oxide, silica, aluminum powder, copper powder or the like, or subjected to surface processing such as metal deposition is also used.

(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 adhesion property that closely adheres 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 inherent high reflection performance.

  The resin used as the binder for the adhesive layer is not particularly limited as long as it satisfies the above conditions of adhesiveness, heat resistance, and smoothness. Polyester resin, acrylate resin, melamine resin, epoxy resin Resin, polyamide resin, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin, etc. can be used alone or a mixture of these resins. From the point of weather resistance, mixed resin of acrylate resin, polyester resin and melamine resin It is more preferable to use a thermosetting resin mixed with a curing agent such as isocyanate.

  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 from 0.01 to 5 [mu] m, more preferably from 0.1 to 2 [mu] m, from the viewpoints of adhesion, smoothness, reflectance of the reflector, 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.

  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.

  Specifically, homopolymers or copolymers of methyl acrylate, acrylic acid, ethyl acrylate, butyl acrylate, propyl acrylate, butyl methacrylate, acrylonitrile, hydroxyethyl acrylate, isononyl acrylate, stearyl acrylate, etc. Can be mentioned. 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 such as F5M, F6Q, and F2F manufactured by Oji Tac Co., Ltd. can also be used as acrylic.

(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 these, 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 the opposite side with respect to the support.

(Other component layers)
In the light reflecting film for solar power generation of the present invention, it is preferable to provide a metal corrosion preventing layer, an ultraviolet absorbing layer and the like as other constituent layers.

(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, polyester resins and acrylic resins can be used. The resin is preferably a thermosetting resin 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 It is desirable to select from a compound having a ring, a copper chelate compound, a thiourea, a compound having a mercapto group, at least one kind of naphthalene, 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-2,5dimethylpyrrole, N-phenyl-3-formyl-2,5-dimethylpyrrole, N-phenyl-3, 4-diformyl-2,5-dimethylpyrrole, etc., 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) benzotriazole, etc. Or a mixture thereof.

  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-phenyl Rumyl imidazole, 4-methyl-5-formyl imidazole, 2-ethyl-4-methyl-5-formyl imidazole, 2-phenyl-4-methyl-4-formyl imidazole, 2-mercaptobenzimidazole, etc., or these Of the mixture.

  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 phenolic antioxidants include 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 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 , Triethylene glycol bis [3- (3-t-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, pentaerythritol-tetrakis- (β-lauryl-thiopropionate), and the like.

  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 and the like.

  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.

  Other nickel-based UV stabilizers include [2,2′-thiobis (4-t-octylphenolate)]-2-ethylhexylamine nickel (II), nickel complex-3,5-di-t-butyl-4- Hydroxybenzyl phosphate monoethylate, nickel dibutyl-dithiocarbamate and the like 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.

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

  For example, polyester resin, urethane resin, polyvinyl acetate resin, acrylic resin, nitrile rubber, or the like is 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.

<Metal base material>
Examples of the metal substrate to which the solar power generation reflecting device of the present invention is attached include steel plate, copper plate, aluminum plate, aluminum plated steel plate, aluminum alloy plated steel plate, copper plated steel plate, tin plated steel plate, chrome plated steel plate, stainless steel plate, etc. A metal material having high conductivity 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. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
(Synthesis of polysiloxane A)
In a 500 ml flask under nitrogen gas filling, 108 parts of ethanol, 319 parts of tetraethoxysilane, 20 parts of distilled water and 1 part of 1% hydrochloric acid were mixed and maintained at 85 ° C. for 3 hours. Hold at 50 ° C. for 50 minutes. Thereafter, it was cooled to obtain polysiloxane A.

(Synthesis of polydimethylsiloxane graft copolymer A)
Under nitrogen gas filling, 51 parts of toluene and 49 parts of methyl isobutyl ketone were heated to 80 ° C. in a 500 ml flask. Separately, 26 parts methacrylic acid, manufactured by Daicel Chemical Industries, 36 parts Plaxel FM-5 (polycaprolactone methacrylic ester), manufactured by Shin-Etsu Chemical Co., Ltd., X-22-174DX (single-end methacryl-modified polydimethylsiloxane) 20 Parts, 1 part of ABN-E (azobis-2-methylbutyronitrile) manufactured by Nippon Hydrazine Kogyo Co., Ltd. were mixed and stirred. This mixed solution was dropped into the above mixed solution of toluene and methyl isobutyl ketone over 2 hours, and then a reaction for 8 hours was performed to obtain a polydimethylsiloxane-based graft copolymer A having a solid content of 50%.

(Preparation of coating solution 1)
86 parts of polydimethylsiloxane graft copolymer A and 13 parts of polysiloxane A produced by Takeda Pharmaceutical Co., Ltd., Tacnate D-170N (crosslinking agent HMDI isocyanurate, solid content 100%, isocyanate 20.7%) 37 Parts were mixed to prepare coating solution 1.

(Synthesis of polysiloxane B)
In a 500 ml flask under nitrogen gas filling, 108 parts of ethanol, 268 parts of methyltrimethoxysilane, 24 parts of γ-methacryloxypropylmethyldimethoxysilane, 99 parts of distilled water, 1 part of 1% hydrochloric acid, and 0.1 part of hydroquinone monomethyl ether are mixed. Then, polysiloxane was synthesized. The synthesized polysiloxane was adjusted to a concentration of 50% with methyl isobutyl ketone to synthesize polysiloxane B.

(Synthesis of polydimethylsiloxane graft copolymer B)
The monomer composition was 22 parts methyl methacrylate, 24 parts butyl methacrylate, 23 parts 2-hydroxyethyl methacrylate, 9 parts polysiloxane B produced above, 1 part methacrylic acid, and X-22-174DX (manufactured by Shin-Etsu Chemical Co., Ltd.). Polydimethylsiloxane graft copolymer B having a solid content of 50% in the same manner as the synthesis of polydimethylsiloxane graft copolymer A, except that 21 parts of methacrylic modified polydimethylsiloxane (molecular weight 5000) was changed to 21 parts. Was synthesized.

(Preparation of coating solution 2)
84 parts of the above-prepared polydimethylsiloxane graft copolymer B and Daicel Chemical Industries, Plaxel 410D, molecular weight 1000, OH number 220 (tetrafunctional caprolactone polyol) 16 parts, Takeda Pharmaceutical Co., Ltd., Takunate D A coating solution 2 was prepared by mixing 36 parts of -170N (crosslinking agent HMDI isocyanurate, solid content 100%, isocyanate 20.7%).

(Synthesis of polydimethylsiloxane graft copolymer C)
The monomer composition was methyl methacrylate 24 parts, butyl methacrylate 26 parts, 2-hydroxyethyl methacrylate 25 parts, methacrylic acid 1 part, and Shin-Etsu Chemical Co., Ltd., X-22-174DX (one-end methacryl-modified polydimethylsiloxane, Polydimethylsiloxane graft copolymer C having a solid content of 50% was synthesized in the same manner as the synthesis of polydimethylsiloxane graft copolymer A except that the molecular weight was changed to 24 parts.

(Preparation of coating solution 3)
84 parts of polydimethylsiloxane graft copolymer C and 12 parts of polysiloxane A produced above, manufactured by Daicel Chemical Industries, Plaxel 410D, molecular weight 1000, OH number 220 (tetrafunctional caprolactone polyol) 14 parts, Takeda Pharmaceutical Co., Ltd. ), Tacnate D-170N (crosslinking agent HMDI isocyanurate, solid content 100%, isocyanate 20.7%) was mixed to prepare coating solution 3.

(Synthesis of polydimethylsiloxane graft copolymer D)
Under nitrogen gas filling, 51 parts of toluene and 49 parts of methyl isobutyl ketone were heated to 80 ° C. in a 500 ml flask. Separately, 26 parts of methacrylic acid, manufactured by Daicel Chemical Industries, 36 parts of Plaxel FM-5 (polycaprolactone methacrylic ester), 9 parts of polysiloxane B, manufactured by Shin-Etsu Chemical Co., Ltd., X-22-174DX (methacrylic modified at one end) 20 parts of polydimethylsiloxane) and 1 part of ABN-E (azobis-2-methylbutyronitrile) manufactured by Nippon Hydrazine Kogyo Co., Ltd. were mixed and stirred. This mixed solution was added dropwise to the previous mixed solution of toluene and methyl isobutyl ketone over 2 hours, and then a reaction for 8 hours was performed to obtain a polydimethylsiloxane graft copolymer D having a solid content of 50%.

(Preparation of coating solution 4)
86 parts of the polydimethylsiloxane graft copolymer D86 produced above and 37 parts of Takeda Pharmaceutical Co., Ltd., Tacnate D-170N (crosslinking agent HMDI isocyanurate, solid content 100%, isocyanate 20.7%) were mixed, Coating solution 4 was prepared.

(Preparation of coating solution 6)
110 parts of the above prepared polydimethylsiloxane graft copolymer C, Takeda Pharmaceutical Co., Ltd., Tacnate D-170N (crosslinking agent HMDI isocyanurate, solid content 100%, isocyanate 20.7%) 34 parts are mixed, A coating solution 6 was prepared.

(Preparation of coating solution 7)
90 parts of the prepared polydimethylsiloxane graft copolymer A and 37 parts of Takunate D-170N (crosslinker HMDI isocyanurate, solid content 100%, isocyanate 20.7%) manufactured by Takeda Pharmaceutical Company Limited were mixed. A coating solution 7 was prepared.

(Preparation of coating solution 8)
100 parts of the polysiloxane A produced above and 37 parts of Takunate D-170N (crosslinker HMDI isocyanurate, solid content 100%, isocyanate 20.7%) manufactured by Takeda Pharmaceutical Co., Ltd. were mixed to prepare a coating solution 8. .

(Preparation of coating solution 9)
100 parts of the above prepared polysiloxane A, Daicel Chemical Industries, Plaxel 410D, molecular weight 1000, OH number 220 (tetrafunctional caprolactone polyol) 14 parts, Takeda Pharmaceutical Co., Ltd., Takunate D-170N (crosslinking agent HMDI) 37 parts of isocyanurate, solid content 100%, isocyanate 20.7%) were mixed to prepare coating solution 9.

[Production of film mirror]
(Preparation of film mirror 11)
10% by mass of an ultraviolet absorber (TINUVIN 928, manufactured by BASF Japan Ltd.) in an acrylic film when forming a thermoplastic polymethyl methacrylate resin film (hereinafter also simply referred to as an acrylic film) having a weight average molecular weight of 100,000 and a number average molecular weight of 50,000. A resin base material (film A) having a thickness of 50 μm was prepared.

  On the film A, as a surface layer, a line speed of 15 m / min, a tension of 3 N is applied using CPC-XL 14.5 / M / W manufactured by Yasui Seiki so that the coating liquid 1 prepared as described above has a dry film thickness of 10 μm. / Applied and dried under conditions of full width and drying temperature of 85 ° C., and then stored at 80 ° C. for 168 hours to produce a 300-m roll film B1.

(Preparation of film C)
On the surface opposite to the surface layer of the film B1, as a bonding layer, a resin in which a polyester resin and a TDI (tolylene diisocyanate) isocyanate are mixed at a resin solid content ratio of 10: 2 is coated by a gravure coating method. Then, a layer having a thickness of 6 μm was formed to produce a film C.

  On the adhesive layer of the film C, a silver reflective layer having a thickness of 80 nm was formed as a metal reflective layer by a vacuum vapor deposition method to obtain a film D.

  Toyo Ink Co., Ltd. BPS-5296 (solid content 50%) and curing agent BXX4773 were mixed at a ratio of 1 / 0.005 to prepare an adhesive solution. This pressure-sensitive adhesive liquid was applied on the silver reflective layer of film D so as to have a thickness of 25 μm, and laminated with a 25 μm-thick polyethylene terephthalate film as a release sheet at a laminating pressure of 2 Mpa to obtain film mirror 11 of the present invention.

(Production of film mirrors 12 to 14)
In the production of the film mirror 11, films B2 to B4 were respectively obtained in the same manner except that the coating liquid 1 was changed to the coating liquids 2 to 4. Film mirrors 12 to 14 were produced in the same manner except that the coating liquid 1 was changed to the coating liquid 2.

(Preparation of film mirror 15)
(Preparation of film B5)
In the production of the film mirror 11, a film mirror 15 was produced in the same manner except that the film B1 was changed to the film A.

(Production of film mirrors 16 to 19)
In the production of the film mirror 11, film mirrors 16 to 19 were produced in the same manner except that the coating liquid 1 used for the production of the film B1 was changed to the coating liquids 6 to 9.

[Evaluation of film mirror]
The following evaluation was performed about produced films B1-9 and film mirrors 11-19.

(Blocking state)
About the film A and the films B1-B9, the blocking state was observed visually in the state where each film full length 300m and width 300mm were wound around the 76cm core, and the following reference | standard evaluated.

◎: No blocking occurred ○: There was a little blocking △: There was a little blocking ×: A lot of blocking occurred (surface state)
The produced release sheets of the film mirrors 11 to 19 were peeled off, overlapped with an aluminum substrate having a length of 1.5 m and a width of 400 mm, passed through a gap between two rollers, and 10 m / min. Pasted at the speed of.

The entire surface of the film mirror attached to the aluminum substrate was visually observed, and the number of film floats and wrinkles generated per 1 m ² was measured and evaluated according to the following criteria.

○: No film floating or wrinkle △: 1 to 2 places, film floating or wrinkles ×: 3 places or more, film floating or wrinkles (variation of regular reflectance)
The produced release sheets of the film mirrors 11 to 19 were peeled off, overlapped with an aluminum substrate having a length of 1.5 m and a width of 400 mm, passed through a gap between two rollers, and 10 m / min. Pasted at the speed of.

  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. About the film mirror affixed on the aluminum base material, the regular reflectance with a reflection angle of 5 degrees was measured. Evaluation was measured as an average reflectance of 350 to 700 nm. 20 points of each sample were measured, and the difference between the maximum value and the minimum value was measured and evaluated according to the following criteria.

◎: Difference between the maximum and minimum values of regular reflectance is less than 1% ○: Difference between the maximum and minimum values of regular reflectance is 1% or more and less than 3% △: Difference between the maximum and minimum values of regular reflectance Is 3% or more and less than 5% x: The difference between the maximum value and the minimum value of regular reflectance is 5% or more.

  From Table 1, it can be seen that the film mirrors 11 to 14 of the present invention have a good surface state and less fluctuation in regular reflectance than the film mirrors 15 to 19 of the comparative example. This is because in the film mirror of the present invention, unnecessary stress from the two rollers was not applied to the film mirror when it was attached to the aluminum base material, and the film mirror could be stably attached while maintaining a good surface state. it is conceivable that.

Example 2
[Production of film mirror]
(Preparation of film mirror 21)
On a polyethylene terephthalate film having a thickness of 40 μm, a resin in which a polyester resin and a TDI (tolylene diisocyanate) isocyanate are mixed at a resin solid content ratio of 10: 2 is coated by a gravure coating method to form a thick adhesive layer. A layer having a thickness of 0.1 μm was formed, and a silver reflective layer having a thickness of 80 nm was further formed thereon by a vacuum deposition method to obtain a film E.

  Made by Toyo Ink Co., Ltd., LIS-601 (solid content 50%), curing agent CR-001, and ethyl acetate are mixed at a ratio of 1 / 0.1 / 1.18, and it is optimal for coating with ethyl acetate An adhesive solution was prepared by diluting to a viscosity of

  Using the obtained adhesive liquid on the silver reflective layer of film E, CPC-XL14.5 / M / W manufactured by Yasui Seiki, line speed 10 m / min, tension 3 N / full width, drying temperature 60-80 ° C. After coating and drying under conditions, the adhesive pressure was 6 μm at a laminating pressure of 2.0 Mpa, and then the film was bonded to the acrylic film of the film B1 produced in Example 1 to produce a film mirror 21.

(Production of film mirrors 22 to 24)
In the production of the film mirror 21, film mirrors 22 to 24 were produced in the same manner except that the film B1 was changed to the films B2 to B4.

(Preparation of film mirror 25)
In the production of the film mirror 21, a film mirror 25 was produced in the same manner except that the film B1 was changed to the film A.

(Production of film mirrors 26 to 29)
In the production of the film mirror 21, film mirrors 26 to 29 were produced in the same manner except that the film B1 was changed to the films B6 to B9.

[Evaluation of film mirror]
(undulation)
The bonding failure of the whole surface of the film mirror which bonded the film E, film B1-4, film B6-9, and film A4 was observed visually, and the following reference | standard evaluated.

○: There is no undulation of undulations △: Slight undulations of undulations x: There are undulations of large undulations or many undulations of small undulations (peeling)
The film mirror obtained by bonding the film E and the film B was left in an environment of 90 ° C., 90% RH, 168 hr, and then the peeling of the adhesive surface was visually observed and evaluated according to the following criteria.

○: No peeling Δ: Some peeling at the end of the film ×: The peeling area of the film has reached 5% of the total The evaluation results are shown in Table 2.

  From Table 2, it turns out that the film mirrors 21-24 of this invention have a favorable bonding state, and there are few peeling of bonding compared with the film mirrors 25-29 of a comparative example. This is considered to be because blocking during film conveyance is reduced and unnecessary in-film stress is eliminated during bonding.

Example 3
[Production of film mirror]
(Preparation of film mirror 31)
Toyo Ink Co., Ltd. BPS-5296 (solid content 50%) and curing agent BXX4773 were mixed at a ratio of 1 / 0.005 to prepare an adhesive solution. This adhesive solution was applied onto the polyethylene terephthalate film of the film mirror 21 produced in Example 2 so as to have a thickness of 25 μm, and laminated with a 25 μm-thick polyethylene terephthalate film as a release sheet at a laminating pressure of 2 Mpa, A film mirror 31 was produced.

(Production of film mirrors 32-39)
In the production of the film mirror 31, film mirrors 32 to 34 were produced in the same manner except that the film mirror 21 was changed to the film mirrors 22 to 24 produced in Example 2.

[Evaluation of film mirror]
The peeled sheet of the produced film mirror is peeled off, overlapped with an aluminum substrate having a length of 1.5 m and a width of 400 mm, passed through a gap between two rollers, and pasted at a pressure of 2.0 Mpa at a speed of 10 m / min. The surface state and regular reflectance were evaluated in the same manner as in Example 1.

(Moisture and light resistance test)
The produced film mirror was allowed to stand for 10 days under conditions of 85 ° C. and 85% RH, and then irradiated with ultraviolet rays for 7 days in an environment of 40 ° 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 variation in regular reflectance of Example 1. 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.

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 decrease rate of the regular reflectance is 20% or more.

  From Table 3, it can be seen that the film mirrors 31 to 34 of the present invention have a good surface state and less fluctuation in regular reflectance than the film mirrors 35 to 39 of the comparative example. This means that unnecessary stress from the two rollers is not applied to the film mirror when affixing to an aluminum substrate, and it can be affixed stably while maintaining a good surface condition. This is thought to be due to the fact that it was able to maintain a stable state.

Claims (4)

  The outermost surface on the sunlight incident side has a surface layer containing a copolymer composed of polysiloxane, polycaprolactone and a polydimethylsiloxane copolymer, one or more resin base materials, and a metal reflective layer. A light reflecting film for solar thermal power generation.   The light reflecting film for solar thermal power generation according to claim 1, wherein the polysiloxane is contained in a skeleton of a polydimethylsiloxane copolymer.   3. The light reflecting film for solar thermal power generation according to claim 1, wherein the polycaprolactone is contained in a skeleton of a polydimethylsiloxane copolymer.   It is a reflective apparatus for solar thermal power generation using the light reflective film for solar power generation of any one of Claims 1-3, Comprising: It has the said surface layer on both sides of the resin base material of the said light reflective film for solar thermal power generation A solar power generation reflecting device, characterized in that it is formed by attaching a light reflecting film for solar power generation on a metal base material through an adhesive layer coated on the surface of the resin base opposite to the side.