JP5593970B2 - Reflector for solar power generation - Google Patents

Description

  The present invention relates to a solar power generation reflection device, and more particularly to a solar power generation reflection device having a dew condensation prevention function.

  In recent years, global warming due to carbon dioxide emitted when using fossil fuel energy such as oil and natural gas has become a common international recognition, and carbon dioxide reduction has become an urgent task. In order to reduce carbon dioxide, it is important to shift from fossil fuels to natural energy. Among them, solar energy, which is the most stable alternative energy for fossil fuels and has a large total energy, is attracting attention. As a solar energy utilization technology, power generation (solar thermal power generation) using high-density thermal energy obtained by concentrating light using a number of mirrors and being obtained at the focal point has become active in countries such as Europe and the United States. .

  However, a problem that occurs in mirrors used in solar thermal power generation is a decrease in reflectance due to dirt. Areas suitable for solar power generation are areas with a large total amount of solar energy per year, and there are many desert areas and dry areas. In these countries, dirt due to adhesion of dust to the mirror is likely to occur.

  In particular, dew condensation is a factor that promotes adhesion of dirt to the mirror. In desert and dry areas suitable for solar thermal power generation, radiant cooling is strong and the temperature difference between day and night structures is large. Therefore, often below the dew point temperature of air. In the air cooled by the structure that is below the dew point temperature of the air, the water vapor contained in the structure aggregates and adheres to the structure. This is condensation. Water droplets generated by condensation absorb dust in the air, and when moisture evaporates due to solar radiation, the dust remains on the surface of the structure. This is the cause of contamination due to condensation. If the reflectivity of the mirror decreases due to this contamination, the efficiency of the power plant itself decreases. Therefore, although the mirror is cleaned for the maintenance of the plant, the larger the plant is, the larger the total area of the mirror becomes, so that the maintenance becomes difficult. Therefore, a technique has been developed that reduces the frequency of dirt adhesion by preventing condensation on the mirror.

  For example, Patent Document 1 discloses a technique for attaching a heater in order to prevent a temperature drop of a mirror at night. Conventionally known technologies to generate heat by flowing electricity to prevent condensation, but it is not preferable to consume power to prevent condensation, and reflective mirrors for solar thermal power generation are used in desert areas, etc. In view of the fact that it is often installed in the network, it is difficult to secure a power source, which is not preferable as a solution. Moreover, it is not realistic to attach to each of thousands to tens of thousands of mirrors.

  As another method, Patent Document 2 discloses a method in which water is used as a heat storage material to increase the heat capacity of the mirror itself to prevent a temperature drop due to radiation cooling. In this preceding example, a bag containing water having a large heat capacity is installed on the back surface of a stainless steel curved mirror. In this case, although cooling by radiation cooling is performed from the mirror, since stainless steel has high thermal conductivity, it is easy to receive supply of heat from the water on the back surface, and there is no sudden temperature drop. This known example requires a mirror having good thermal conductivity. Since this example is applied to a curved mirror, the position of the mirror is fixed. However, since a mirror for solar power generation requires solar tracking, the direction of the mirror changes. Therefore, when a liquid heat storage material is used, when the mirror faces the zenith direction, the heat storage material and the mirror are not in contact with each other. In addition, in conventional solar thermal power generation, a back mirror with a silver metal layer on the back side of the glass is used, but the thermal conductivity of the glass is low, and condensation is generated on the glass surface without transferring heat from water. End up. Metallic silver is an excellent reflector with high reflectivity and thermal conductivity, but it has no weather resistance and cannot be used as it is as a mirror.

  In Patent Documents 3 and 4, a method for preventing dew condensation by installing a blower device on a road reflector, detecting a threshold value by a sensor sensing method, sending air, and reducing a temperature difference between the outside air and the mirror surface. Is disclosed. In this case as well, a power source is required, which is not preferable as a solution.

Japanese Patent Laid-Open No. 10-5090 Japanese Patent No. 4157867 JP 2008-88644 A JP 2009-167782 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a solar power generation reflection device that hardly causes condensation on a mirror even under severe conditions where the temperature difference between day and night is large. In particular, it is an object to provide a solar power generation reflector that is unlikely to form a dew on a mirror even when the temperature changes drastically in the desert, even if it cools at night and the humidity increases.

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

1. In a solar power generation reflecting device having a film mirror having a silver reflecting layer on a resin substrate and a support for supporting the film mirror, the support has a heat capacity of 90 kJ / K or more per 1 m ^{2 of the} film mirror back surface. A solar power generation reflector having a thermal conductivity of 50 W / (m · K) or more.

  2. 2. The solar power generation reflecting device according to 1 above, wherein the film mirror has a thickness of 50 μm or more and 200 μm or less.

  3. The said support body is covered with the heat insulating material which has a thermal conductivity of 0.10 W / (m * K) or less except a sunlight incident surface, The reflection for solar power generation of said 1 or 2 characterized by the above-mentioned. apparatus.

  According to the present invention, it has been possible to provide a solar power generation reflecting device in which dew condensation on a mirror is difficult even under severe conditions where the temperature difference between day and night is large.

  Hereinafter, embodiments for carrying out the present invention will be described in detail.

As a result of intensive studies in view of the above problems, the inventor of the present invention has a film mirror having a silver reflection layer on a resin substrate and a support for supporting the film mirror. Has a heat capacity of 90 kJ / K or more per 1 m ^{2 of the} film mirror back surface and a thermal conductivity of 50 W / (m · K) or more. In order to prevent the stored heat from falling below the dew point even when the temperature becomes low at night, it has been found that a reflector for solar power generation that is difficult to condense on the mirror can be realized, leading to the present invention. It depends on you.

(Summary of the configuration of the solar power generation reflector)
The reflector for solar power generation according to the present invention includes at least a film mirror and a support. The said mirror is a film mirror which has a resin base material and a silver reflection layer, and a support body has high heat storage property and high heat conductivity.

[Film mirror]
The film mirror is preferably a film mirror in which an adhesive layer, a silver reflective layer, an upper adjacent layer, and a protective layer are provided in this order as constituent layers on a resin substrate. As the constituent layer, special functional layers such as a gas barrier layer and a scratch-preventing layer can be further provided.

  The thickness of the film mirror described above is preferably 50 μm or more and 200 μm or less.

  Preferably they are 80 micrometers or more and 150 micrometers. If it is thicker than 50 μm, it is excellent in strength and operability when pasting on a support described later, and if it is thinner than 200 μm, the heat stored in the support is particularly when the resin substrate is between the reflective layer and the support. However, it is easy to be transmitted to the film surface and the effect of preventing condensation is good.

[Resin substrate layer]
As the resin base material layer according to the present invention, various conventionally known resin films can be used. 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, norbornene resin film , Polymethylpentenef Can Lum, polyether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, and acrylic films. Among these, polycarbonate film, polyester film, norbornene resin film, and cellulose ester film are exemplified.

  In particular, it is preferable to use a polyester film or a cellulose ester film, and it may be a film manufactured by melt casting or a film manufactured by solution casting.

  Although the thickness of the said resin base material can be preferably used within the range of 10-300 micrometers, More preferably, it is 50-195 micrometers, Most preferably, it is 80-145 micrometers.

  Moreover, it is preferable to make the resin base material layer contain a corrosion inhibitor and an ultraviolet absorber as described later according to the purpose.

[Reflective layer]
The reflective layer can be provided by depositing or plating a metal. Among them, a silver reflective layer produced by vapor deposition or plating of silver has a high reflectance and is particularly preferable as a reflective layer of a solar power generation reflective device. As a method for forming the silver reflective layer, 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, it is preferable that it is a manufacturing method of the aspect which has the process of forming the said silver reflection layer by silver vapor deposition as a manufacturing method of the film mirror which manufactures the film mirror of this invention.

  The thickness of the 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 silver reflective layer may be on the light incident side with respect to the support or on the opposite side, but since the support is a resin, for the purpose of preventing resin degradation due to light, It is preferable to be positioned on the light incident side.

[Upper adjacent layer]
The upper adjacent layer used in the film mirror of the present invention is adjacent to the side of the silver reflective layer that is far from the resin base material, and prevents corrosion deterioration of the silver and prevents damage to the silver reflective layer and is formed outside the upper adjacent layer. This contributes to the improvement of the adhesive strength with the barrier layer and the scratch prevention layer. It can also be used as the uppermost layer as a protective layer.

  The resin used as the binder for the upper adjacent layer may 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 or an acrylic resin may 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 upper adjacent layer is preferably 0.01 to 3 μm, more preferably 0.1 to 1 μm, from the viewpoints of adhesion, weather resistance, and the like.

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

  The adjacent layer preferably contains a corrosion inhibitor or an ultraviolet absorber as described later depending on the purpose.

[Adhesive layer]
The adhesive layer has a function of improving the adhesiveness between the resin base material and the reflective layer by being provided on the resin base material (resin film). The adhesive layer is preferably made of a resin. Therefore, the adhesive layer has adhesiveness 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, acrylic resin, melamine resin, epoxy Resin, polyamide resin, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin or the like can be used alone or a mixed resin thereof. From the viewpoint of weather resistance, a polyester resin and a melamine resin mixed resin are preferable. Furthermore, it is more preferable to use a thermosetting resin mixed with a curing agent such as isocyanate.

  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 the 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.

  Further, the adhesive layer preferably contains a corrosion inhibitor and an ultraviolet absorber as described later depending on the purpose.

(Corrosion inhibitor)
In the film mirror of the present invention, a corrosion inhibitor for the reflective layer may be used. The corrosion inhibitor can be broadly classified into a corrosion inhibitor and an antioxidant having an adsorptive group for the metal reflection layer.

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

  The film mirror of the present invention may be an embodiment in which the adhesive layer contains an antioxidant and the upper adjacent layer contains a corrosion inhibitor having an adsorptive group for silver.

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

(Corrosion inhibitor having an adsorptive group for silver)
Corrosion inhibitors having an adsorptive group for silver 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 Cyclohexylamine 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 a corrosion inhibitor for the silver reflective layer used in the film mirror 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.

  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.

(UV absorber)
In the present invention, it is preferable to add an ultraviolet absorber for the purpose of preventing deterioration due to sunlight or ultraviolet rays. It is preferable that any one of the constituent layers provided on the resin substrate 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.

[Adhesive layer]
It is preferable to provide an adhesive layer for bonding the support of the solar power generation reflecting device and the film mirror. The pressure-sensitive adhesive is not particularly limited, and for example, any of a dry laminating agent, a wet laminating agent, a pressure-sensitive adhesive, a heat sealant, 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 5 to 50 μm from the viewpoint of the pressure-sensitive adhesive effect, the drying speed, and the like. With this thickness, there is no problem with the overall thermal conductivity, but it is more preferable that the adhesive itself has thermal conductivity (1 W / (m · K) or more).

  Specific adhesive layers include ADY's HS80-S, Soken Chemical's "SK Dyne Series", Toyo Ink's Oribain BPW Series, BPS Series, Arakawa Chemical's "Arcon" "Superester" "High Pale" ”, A pressure sensitive adhesive such as 1225B manufactured by Three Bond Co., Ltd. is preferably used. Among these, HS80-S manufactured by ADY is preferable among these.

  From the viewpoint of heat transfer, it is important that the support and the film mirror are as close as possible. In the present invention, it is preferable that 95% or more of the back surface of the film mirror is in close contact. It is preferably 98% to 100% in close contact.

[Support]
The support of the present invention is required to be a heat storage body having a high heat capacity and thermal conductivity for reducing the temperature drop of the film mirror. The amount of heat from the outside air flows into the support located on the back of the film mirror through the film mirror at high temperatures during the daytime. At this time, the external heat quantity is stored in the support. At night, when heat radiation decreases and only the film mirror itself emits heat, the film mirror is supplied with heat from the support, preventing a sudden drop in temperature and preventing the temperature from dropping below the dew point temperature. It becomes possible.

In this invention, it turned out that a support body has heat storage property and in order to show the effect of this invention, the heat capacity of 90 kJ / K or more per 1 m < ² > of film mirror back surfaces is required. It is preferable that the material has a heat capacity of 120 kJ / K or more. The heat capacity is a value obtained by multiplying the specific heat capacity of the support material by its mass. A high specific heat capacity is preferable because the mass of the support may be small and the volume does not increase. The specific heat capacity of the support is determined by the material, but is preferably 100 J / (kg · K) or more. The upper limit is not particularly limited, but the upper limit is about 1000 J / (kg · K) due to the properties of the material.

  The thermal conductivity of the support needs to be 50 W / (m · K) or more. When this value is low, heat does not move efficiently. Preferably, it is 100 W / (m · K) or more. This value is also determined by the properties of the material, and the upper limit is about 400 W / (m · K).

Examples of the support material that satisfies such specific heat capacity and thermal conductivity include pure aluminum, aluminum alloy, pure copper, brass, pure iron, tungsten steel (W content 5% or less), and chromium steel (Cr content 2%). And carbon steel (C content 0.5% or less) and manganese steel (Mn content 1% or less). Aluminum alloys 5000 series, 6000 series, and 7000 series having a specific gravity of 2.7 g / cm ³ and excellent corrosion resistance are more preferable in terms of mass.

  The support is also a rigid body for maintaining the surface accuracy of the film mirror, and the surface roughness of the support on the film mirror side is preferably in the range of 15 to 100 nm. Within this range, slight irregularities on the surface of the support are absorbed by the adhesive layer, and the flatness of the film mirror and the adhesion between the film mirror and the support are less affected.

  The above characteristic values can be measured by a general method.

  The surface roughness can be measured by a general method. For example, it can be carried out using a Wyko NT9300 optical profiler manufactured by Veeco or an ultra-high precision three-dimensional measuring machine (UA3P) manufactured by Panasonic.

  The value of the heat capacity of the metal is well known and can be measured, for example, by a differential scanning calorimeter (DSC3000SA series) manufactured by Bruker AXS.

  The thermal conductivity of metals is also well known and can be measured according to JIS R1650-3 or the like.

[Insulation]
The support is preferably covered with a heat insulating material other than the sunlight incident surface. Although the thickness of a heat insulating material layer is not specifically limited, Although it can set suitably according to desired heat insulation, Preferably it is 10-50 mm, More preferably, it is about 20-40 mm.

  The thermal conductivity of the heat insulating material layer is preferably 0.10 W / (m · K) or less, more preferably 0.06 W / (m · K) or less. As for the lower limit of the thermal conductivity, the lower the thermal conductivity, the better. However, 0.02 W / (m · K) or more is preferable because it involves an increase in cost and thickness.

  What is necessary is just to select the heat insulating material which can be used from a well-known heat insulating material. For example, plastic foams such as polystyrene, polyurethane, and polyethylene can be used. These are because the workability with respect to the shape is good and easy to handle, and moisture in the surrounding environment is relatively difficult to penetrate into the heat insulating material. Particularly preferred are polystyrene foams.

  In addition, in order to prevent the moisture in the air in the surrounding environment from permeating the heat insulating material and condensing as much as possible, it is possible to coat a latex made of polyvinylidene chloride with low moisture permeability, or to insulate similar films and aluminum foil, etc. It may be attached to the outside of the material with an adhesive or the like.

  Further, the heat insulating material is typed so as to be as close as possible to the support. This is because if there is a space in the periphery, moisture contained in the space is condensed with cooling. Therefore, it is preferable to make the surrounding space as small as possible so that the processing of the heat insulating material is not too complicated, and to make the heat insulating material adhere to the support.

  The heat insulating material is preferably fixed to the back surface in order to prevent heat radiation from the film mirror support to the air, but it is more desirable that the side surface is also covered. In addition, it is more preferable that the structure prevents water from penetrating into the inside, for example, the surface is waterproofed with a resin or the like, assuming sudden rain.

  The fixing method of the heat insulating material may be spraying of the heat insulating material, attaching the sheet-like heat insulating material with an adhesive, screwing, or the like.

  Hereinafter, the present invention will be specifically described using examples and comparative examples.

(Production of film mirror)
A biaxially stretched polyester film (polyethylene terephthalate film, thickness 100 μm) was used as the resin substrate.

  On one side of the polyethylene terephthalate film, a polyester resin (Polyester SP-181 manufactured by Nippon Synthetic Chemical), a melamine resin (manufactured by Super Becamine J-820 DIC), TDI isocyanate (2,4-tolylene diisocyanate), HDMI In a solution in which isocyanate (1,6-hexamethylene diisocyanate) is mixed in toluene at a resin solid content ratio of 20: 1: 1: 2 and a solid content concentration of 10%, glycol diisocyanate is further added as a corrosion inhibitor. An amount adjusted to a film thickness of 0.2 μm after application of mercaptoacetate was added, and coating was performed by a gravure coating method to form an adhesive layer.

  Further, a silver reflective layer having a thickness of 80 nm is formed on the adhesive layer as a silver reflective layer by vacuum deposition, and a polyester resin (Polyester SP-181, Nippon Synthetic Chemical Co., Ltd.) and TDI isocyanate are formed on the silver reflective layer. In a resin in which (2,4-tolylene diisocyanate) is mixed at a resin solid content ratio of 10: 2, Tinuvin 928 (BASF Japan) is further applied as a benzotriazole-based ultraviolet absorber, and the film thickness is 0.3 μm. An amount adjusted so as to be added was added, and a protective layer was formed by coating by a gravure coating method, and this was cut into a size of 45 cm × 45 cm in length and width to obtain a film mirror 1.

Example 1: (Preparation of solar power generation reflector 1)
The film mirror 1 was attached to one side of an aluminum alloy No. 5056 (manufactured by Sumitomo Light Metal Industry Co., Ltd.) having a length of 45 cm × 45 cm and a thickness of 45 mm using an SK dyne 1717 manufactured by Soken Chemical Co., Ltd. as an adhesive. .

(Creation of insulation)
Using polystyrene for bead foaming (High Beads, manufactured by Hitachi Chemical Co., Ltd.), heat-molded to fit into a size of 45 cm × 45 cm by an in-mold molding method, and a heat insulation box 1 having a wall thickness of 20 mm and a molded product density of 35 kg / m ³ is obtained. Produced. The heat conductivity of the manufactured heat insulation box 1 was 0.0082 W / (m · K) (value at 0 ° C.).

  This is so that the side and the back (the side where the film mirror is not attached) are in close contact with the aluminum alloy 5056 support to which the film mirror 1 is attached, and the height is the same on the film surface and the insulation surface. It attached so that it might become, and the solar power generation reflective apparatus 1 was created.

Example 2: (Preparation of solar power generation reflector 2)
In the same manner as in Example 1, except that the support material alone was replaced with copper as shown in Table 1, a solar power generation reflecting device 2 was produced.

Comparative Examples 1-4: (Preparation of solar power generation reflectors 3-6)
As in Example 1, except that the material of the support and its thickness are changed as shown in Table 1, and the height of the heat insulating material is adjusted so that the film surface and the heat insulating material surface have the same height. Reflectors 3 to 6 for solar thermal power generation were created.

(Dew condensation test)
Abu Dhabi with a large amount of solar radiation was selected as a model for the location of the solar power generation equipment.

  In order to simplify the experiment, a day with high humidity was selected and a dew condensation test was conducted in the field.

  Daytime, average temperature 40 ° C dew point temperature 20 ° C, nighttime: in a desert area where average temperature 15 ° C, dew point temperature 10 ° C, film mirror structure solar power generation reflectors 1-6 are installed 1m from the ground surface It was installed in a horizontal state from 18:00 on a clear day to 4 o'clock in the morning, and dew condensation on the surface at 4 o'clock in the morning was observed. The temperature at this time was 10 ° C.

  Evaluation was performed by ranking as follows.

○: Condensation did not occur △: Fine water droplets of condensation formed on the edge of the film mirror ×: Covered by condensation, the water droplets grew and joined to form large water droplets The results of the condensation test are summarized in Table 1.

The heat capacity in the table is a value (kJ / K) obtained by multiplying the heat capacity of the material of the support by the mass, and represents the heat capacity per 1 m ^{2 of} the film mirror back surface.

  As shown in Table 1, regarding the solar power generation reflectors of the samples of Examples 1 and 2 in which both the heat capacity and the heat conductivity are within the scope of the present invention, only the heat capacity is within the scope of the present invention. It can be seen that condensation is less likely to occur on the film mirror than the samples of Comparative Examples 1 and 2 when only the rate is within the scope of the present invention.

Claims (3)

In a solar power generation reflecting device having a film mirror having a silver reflecting layer on a resin substrate and a support for supporting the film mirror, the support has a heat capacity of 90 kJ / K or more per 1 m ^{2 of the} film mirror back surface. A solar power generation reflector having a thermal conductivity of 50 W / (m · K) or more.   The thickness of the said film mirror is 50 micrometers or more and 200 micrometers or less, The solar power generation reflective apparatus of Claim 1 characterized by the above-mentioned.   3. The solar power generation according to claim 1, wherein the support is covered with a heat insulating material having a thermal conductivity of 0.10 W / (m · K) or less except for a sunlight incident surface. Reflector.