JP2012108221A - Reflector for solar thermal power generation, method for manufacturing the same and reflector device for solar thermal power generation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To scarcely develop strain on a mirror face even if being used for a long period under a harsh environment and suppress the lowering of a regular reflectance, namely, to provide a reflector for solar thermal power generation having superior durability and having a favorable regular reflectance to sunlight; and to provide a method for manufacturing the same and a reflector device for the solar thermal power generation.SOLUTION: This reflector for solar thermal power generation is formed by superposing a hard transparent resin substrate with flexural rigidity of 400 N cm, on a reflecting film having a silver reflecting layer provided on a film base material, on one surface. This reflector for the solar thermal power generation is so configured that the hard transparent resin substrate is superposed on the side of the silver reflecting layer surface of the reflecting film via an adhesive layer.

Description

  The present invention relates to a solar power generation reflector having excellent durability and good regular reflectance with respect to sunlight, a manufacturing method thereof, and a solar power generation reflector.

  In recent years, coal energy, biomass energy, nuclear energy, and natural energy such as wind energy and solar energy have been studied as alternative energy to replace fossil fuel energy such as oil and natural gas. The most stable and large amount of natural energy is considered to be solar energy.

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

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

  Since the reflection device is exposed to ultraviolet rays, heat, wind and rain, sandstorms, and the like caused by solar heat, a glass mirror has been conventionally used. Glass mirrors are highly durable to the environment, but they are expensive, inflexible, damaged during transportation, and heavy. There was a problem of bulkiness. Further, the glass mirror has a restriction on the curved surface shape.

  On the other hand, a resin mirror mirror sheet has been considered as a mirror capable of three-dimensional processing (see, for example, Patent Document 1).

  For the purpose of concentrating solar heat, the metal layer is composed of silver having a higher visible light reflectance than the commonly used aluminum reflective layer in terms of obtaining a high reflectance. It is preferable to do. However, although the resin-made reflective sheet using silver is light and safe and can be installed with reduced manufacturing costs, it has a problem that it is inferior in weather resistance and easily deteriorated by ultraviolet rays, oxygen, water vapor, sulfur and the like. In order to solve this problem, Patent Document 2 proposes a mirror film technology including a UV (ultraviolet) shielding acrylic film. However, when these mirror sheets and mirror films were subjected to a long-term durability test in a harsh environment assuming outdoor use as a reflector for solar power generation, the mirror surface was distorted and the regular reflectance decreased. Such a problem occurred.

JP 2005-59382 A Special table 2009-520174

  The present invention has been made in view of the above problems, and its purpose is to prevent the mirror surface from being distorted even when used in a harsh environment for a long period of time, and to suppress a decrease in regular reflectance. It is to be. That is, it is providing the solar power generation reflector which is excellent in durability, and has a favorable regular reflectance with respect to sunlight, its manufacturing method, and a solar power generation reflective apparatus.

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

1. A reflective plate for solar power generation in which a rigid transparent resin substrate having a bending stiffness of 400 N · cm ² or more and a reflective film having a silver reflective layer provided on a film base on one side are laminated, the reflective film A solar power generation reflecting plate, characterized in that is a solar power generation reflecting plate laminated with a hard transparent resin substrate via an adhesive layer on the silver reflection layer surface side.

  2. 2. The solar power generation reflector according to 1 above, wherein the thickness of the hard transparent resin substrate is 0.5 mm or more and 20 mm or less.

  3. The reflector for solar power generation according to 1 or 2, wherein the hard transparent resin substrate is made of polycarbonate resin.

  4). 4. The solar power generation reflector according to any one of 1 to 3, wherein the adhesive layer contains a polyurethane resin.

  5). The solar thermal power generation according to any one of 1 to 4 above, wherein a silver protective layer is provided on the surface of the silver reflective layer of the reflective film having a silver reflective layer provided on the one side of the film base material. Reflector.

  6). A reflector for solar power generation, wherein the reflector for solar power generation according to any one of 1 to 5 is used.

  7). It is a manufacturing method which manufactures the reflecting plate for solar power generation as described in any one of said 1-5, Comprising: The said silver reflecting layer is formed by silver vapor deposition, The manufacturing method of the reflecting plate for solar power generation characterized by the above-mentioned.

  According to the present invention, it is possible to suppress a decrease in regular reflectance even when used as a solar power generation reflecting device in a harsh environment for a long period of time. That is, it is possible to provide a reflector for solar power generation that is light and safe, can be installed with reduced manufacturing costs, has excellent durability, and has a good regular reflectance with respect to sunlight, and a method for manufacturing the same. did it.

It is typical sectional drawing which shows an example of the fundamental structure of the reflecting plate for solar power generation of this invention. It is typical sectional drawing which shows an example of the solar power generation reflective apparatus of this invention.

As a result of intensive studies in view of the above-mentioned problems, the present inventor has made a mirror mirror sheet produced by thermocompression bonding proposed in the prior art (for example, the technique of Patent Document 1 or 2) or a film obtained by laminating soft films. When a long-term durability test was conducted in a harsh environment assuming outdoor use, a reflective film for solar power generation using a solar cell was found to have problems such as distortion on the mirror surface and a decrease in regular reflectance. It was. When investigating the cause, it was estimated that the mirror surface was distorted due to the residual stress at the layer interface, the thermal deformation force of the film alone, and the presence of multiple layer interfaces. A reflector for solar power generation in which a rigid transparent resin substrate having a rigidity of 400 N · cm ² or more and a reflective film having a silver reflective layer provided on a film base on one side are laminated, wherein the reflective film is The solar power generation reflector, which is laminated with a hard transparent resin substrate via an adhesive layer on the silver reflection layer surface side, can be used for a long time in harsh environments assuming outdoor use. It has been found that even when a durability test is performed, it is possible to suppress a decrease in regular reflectance. This is because the combination of the hard transparent resin substrate and the soft reflective film suppresses the residual stress at the layer interface, and further, the adhesive layer functions as a stress relaxation layer, and there is no interface between the soft films. This is estimated as a factor.

  With the above technology, a light and safe reflector that can be installed with reduced manufacturing costs, has excellent durability, and has a good regular reflectance with respect to sunlight, and a manufacturing method thereof, It is up to the present invention.

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

[Configuration of reflector for solar thermal power generation]
The configuration of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the basic configuration of a reflector for solar power generation according to the present invention. The reflector for solar power generation of the present invention is formed by laminating a hard transparent resin substrate 10 and a silver reflective layer surface side of a reflective film having a silver reflective layer 40 provided on a film base 50 on one side with an adhesive layer 20 interposed therebetween. Has been. FIG. 2 is a schematic cross-sectional view showing an example of the solar power generation reflecting device of the present invention. In addition to the basic configuration of the solar power generation reflector described above, the solar power generation reflector on which the silver protective layer 30 is laminated is coated on the film substrate surface opposite to the side having the silver reflection layer. It is formed by being attached to the holding member 70 through the layer 60. In addition, it is also a preferable aspect to provide special functional layers such as a barrier layer and a scratch-preventing layer as a constituent layer of the solar heat reflecting plate. In addition, a reflection film having a silver reflection layer on one side, an adhesive layer, a silver protective layer, a barrier layer, and a scratch prevention layer, etc., a silver corrosion inhibitor described later, an antioxidant described later, an ultraviolet absorber, and light stability An agent or the like may be contained.

(Hard transparent resin substrate)
The rigid transparent substrate used in the present invention has a bending rigidity of 400 N · cm ² or more. In the case of a soft resin substrate lower than 400 N · cm ² , the effect of the present invention cannot be obtained. Preferably at bending stiffness of the rigid transparent substrate 800 N · cm ² or more, further preferably 1500 N · cm ² or more. The upper limit is not particularly limited, but it is 5 × 10 ⁸ N · cm ² for reasons such as difficulty in handling and high price despite no further improvement in practical use.

  The bending stiffness is measured in accordance with the bending stiffness test of the standard for plywood for concrete formwork in “Japanese Agriculture and Forestry Standard for Plywood” (Ministry of Agriculture, Forestry and Fisheries Notification No. 1751, December 2, 2008). It can be calculated from the product of the coefficient and the sectional second moment. In the present invention, since a relatively thick resin substrate is used, if the light transmittance is low, the regular reflectance is undesirably lowered. In the present invention, the transparent resin is a transparent resin having an average transmittance of 75% or more at a wavelength of 380 nm to 700 nm. The average transmittance is preferably 85% or more. The average transmittance can be measured by a known method.

  As resin used for the hard transparent resin substrate of this invention, it is preferable that glass transition temperature (Tg) is 70-500 degreeC.

  Examples of such hard transparent resins include cyclic olefin resins such as norbornene resins, polyarylate resins (PAR), polysulfone resins (PSF), polyethersulfone resins (PES), polyparaphenylene resins (PPP), Polyarylene ether phosphine oxide resin (PEPO), polyimide resin (PPI), polyetherimide resin (PEI), polyamideimide resin (PAI), acrylic resin, polycarbonate (PC) resin, polyethylene naphthalate (PEN) resin, An organic-inorganic nano hybrid material can be mentioned. As the resin for the hard transparent resin substrate, acrylic resin, polycarbonate resin, and norbornene resin are particularly preferable. Among these, polycarbonate (PC) resin is most preferable from the viewpoints of hardness, transparency, price, safety and the like.

  The thickness of the hard transparent resin substrate is not particularly limited as long as it satisfies the bending rigidity of the substrate. However, considering the bending rigidity, transparency, weight, ease of handling, price, practicality, etc., the thickness is 0. 5 mm or more and 20 mm or less are preferable. The hard transparent resin substrate in the present invention may have a substantially constant thickness, or may have at least two types of thickness. Further, the thickness of the hard transparent resin substrate may be changed partially, stepwise or continuously.

  As a method for producing a hard transparent resin substrate, a hard transparent resin substrate having a uniform thickness can be formed by any method such as a cast method or an extrusion method using the hard transparent resin.

  Examples of the method for producing a hard transparent resin substrate having different thicknesses include the following (i) to (iv).

(I) Rigid transparent resin substrate having a laminated portion One or more rigid transparent resin substrates having a uniform area and a uniform thickness are laminated at any location on the rigid transparent resin substrate having a uniform thickness created by the above manufacturing method. By doing this, a hard transparent resin substrate having a part where the thickness of the substrate is different partially or stepwise is manufactured.

(Ii) Rigid transparent resin substrate formed by injection molding Using a mold having a shape having an arbitrary area at an arbitrary location of a portion having a different thickness, a portion having a different thickness by injection molding, A hard transparent resin substrate having stepwise or continuous production is produced.

(Iii) Hard transparent resin substrate formed by hot pressing method After controlling the hard transparent resin substrate having a uniform thickness to have an arbitrary thickness by a method such as hot pressing, the thickness is determined by a known punching method. A hard transparent resin substrate having different parts partially, stepwise or continuously is manufactured.

(Iv) Rigid transparent resin substrate formed by roll pressing method When extruding the rigid transparent resin substrate, by controlling a roll having a non-smooth surface, control is performed to obtain an arbitrary thickness, and then publicly known A hard transparent resin substrate having parts with different thicknesses partially, stepwise or continuously is manufactured by the punching method.

  In particular, when the mold is prepared and prepared using the manufacturing method (iii) to obtain a predetermined shape, it is easy to reduce the thickness of the substrate, and it is possible to adapt to the production adjustment, the design change of the hard transparent resin substrate, etc. It is preferable because the productivity and yield can be improved because the productivity is high and the number of steps is small.

  Details of the resin of the preferred hard transparent resin substrate are described below.

(Acrylic resin)
Preferable specific examples of the acrylic resin include methyl methacrylate resin. The methyl methacrylate resin is a polymer containing 50% by mass or more of methyl methacrylate units. The content of methyl methacrylate units is preferably 70% by mass or more and may be 100% by mass. A polymer having a methyl methacrylate unit of 100% by mass is a methyl methacrylate homopolymer obtained by polymerizing methyl methacrylate alone.

  This methyl methacrylate-based resin is usually a monofunctional monomer mainly composed of methyl methacrylate and a polyfunctional monomer used as necessary, as a radical polymerization initiator and as required. It can be obtained by polymerization in the presence of a chain transfer agent.

  The monofunctional monomer that can be copolymerized with methyl methacrylate is not particularly limited. For example, ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methacrylic acid 2 -Methacrylic acid esters other than methyl methacrylate such as ethylhexyl and 2-hydroxyethyl methacrylate; methyl acrylate, ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-acrylate Acrylic esters such as ethylhexyl and 2-hydroxyethyl acrylate; methyl 2- (hydroxymethyl) acrylate, methyl 3- (hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and 2 Hydroxyacrylic acid esters such as (hydroxymethyl) butyl acrylate; Unsaturated acids such as methacrylic acid and acrylic acid; Halogenated styrenes such as chlorostyrene and bromostyrene; Substituted styrenes such as vinyltoluene and α-methylstyrene Unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; and unsaturated imides such as phenylmaleimide and cyclohexylmaleimide. Such monomers may be used alone or in combination of two or more.

  The polyfunctional monomer that can be copolymerized with methyl methacrylate is not particularly limited. For example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate , Ethylene glycol such as tetraethylene glycol di (meth) acrylate, nonaethylene glycol di (meth) acrylate, and tetradecaethylene glycol (meth) acrylate, or both oligomeric hydroxyl groups esterified with acrylic acid or methacrylic acid One obtained by esterifying both hydroxyl groups of propylene glycol or its oligomer with acrylic acid or methacrylic acid; neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, and One obtained by esterifying a hydroxyl group of a dihydric alcohol such as tandiol di (meth) acrylate with acrylic acid or methacrylic acid; bisphenol A, an alkylene oxide adduct of bisphenol A, or both hydroxyl groups of these halogen-substituted products with acrylic acid or methacrylic acid Esterified with acid; esterified with polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid, and those obtained by ring-opening addition of epoxy groups of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups Succinic acid, adipic acid, terephthalic acid, phthalic acid, dibasic acids such as halogen-substituted products thereof, and alkylene oxide adducts thereof can be added to glycidyl acrylate or glycidyl methacrylate. Those were the carboxy groups by ring-opening addition; aryl (meth) acrylates, and diaryl compounds such as divinylbenzene, and the like. Among these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

  The methyl methacrylate resin preferably used in the present invention may be a modified methyl methacrylate resin modified by a reaction between functional groups of the resin. As the reaction, for example, demethanol condensation reaction in a polymer chain between a methyl ester group of methyl acrylate and a hydroxyl group of 2- (hydroxymethyl) methyl acrylate, and a carboxyl group of acrylic acid and 2- (hydroxymethyl) ) Intrapolymer dehydration condensation reaction with hydroxyl group of methyl acrylate.

  Commercially available methyl methacrylate resins can be easily obtained. For example, “Sumipex” (manufactured by Sumitomo Chemical Co., Ltd.), “Acripet”, “Acrylite”, “Acryprene” "Made by Mitsubishi Rayon Co., Ltd.", "Delpet", "Delagrass" (produced by Asahi Kasei Co., Ltd.), "Parapet" (produced by Kuraray Co., Ltd.), "Paragrass", "Comoglass" (produced by Kuraray Co., Ltd.) and (Made by Nippon Shokubai Co., Ltd.).

  In addition, acrylic resins include other resins (for example, cellulose ester resins, polyethylene, polypropylene, acrylic resins, polyamides, polyphenylene sulfide resins, polyether ether ketone resins, polyesters, polysulfones, polyphenylene oxides, polyacetals, polyimides, polyetherimides). Etc.), a thermosetting resin (for example, phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin, etc.) can be further contained, and an antioxidant, ultraviolet absorber, and light stability described later. Agents, higher fatty acids, acid esters and acid amides, lubricants and plasticizers such as higher alcohols, montanic acid and its salts, esters, half esters, stearyl alcohol, stearamide and ethylene wax Mold release agents such as phosphites, hypophosphites, halogen flame retardants, phosphorous and silicone non-halogen flame retardants, nucleating agents, amines, sulfonic acids, poly An antistatic agent such as an ether, a colorant such as a pigment, and an additive such as acrylic elastic particles may be optionally contained. However, in light of the characteristics required by the application to be applied, it is necessary to add the additive within a range in which the color of the additive does not adversely affect the thermoplastic polymer and the transparency is not lowered.

  In the present invention, the method of blending optional components such as acrylic elastic particles or other additives is not particularly limited, and after pre-blending the acrylic resin and other optional components, usually at 200 to 350 ° C., uniaxial or A method of uniformly melt-kneading with a twin-screw extruder is preferably used.

(Polycarbonate resin)
The polycarbonate resin is usually obtained by reacting a dihydric phenol and a carbonate precursor such as phosgene or diphenyl carbonate by an interfacial polycondensation method or a melt transesterification method. Bisphenol A is used as the dihydric phenol. The aromatic polycarbonate resin used is common. In addition, the thing which superposed | polymerized the carbonate prepolymer by the solid-phase transesterification method, the thing which carried out the ring-opening polymerization of the cyclic carbonate compound, etc. are mentioned.

  The dihydric phenol is not particularly limited as long as it does not impair the performance as a transparent resin. For example, in addition to bisphenol A (2,2-bis (4-hydroxyphenyl) propane), hydroquinone , Resorcinol, 4,4′-dihydroxydiphenyl, bis (4-hydroxyphenyl) methane, bis {(4-hydroxy-3,5-dimethyl) phenyl} methane, 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -4-isopropylcyclohexane, 2,2 -Bis {(4-hydroxy-3-methyl) phenyl} propane, 2,2-bis {(4-hydro Ci-3,5-dimethyl) phenyl} propane, 2,2-bis {(4-hydroxy-3,5-dibromo) phenyl} propane, 2,2-bis (4-hydroxyphenyl) butane, 2,2- Bis (4-hydroxyphenyl) -3-methylbutane, 2,4-bis (4-hydroxyphenyl) -2-methylbutane, 2,2-bis (4-hydroxyphenyl) pentane, 2,2-bis (4-hydroxy) Phenyl) -4-methylpentane, 9,9-bis (4-hydroxyphenyl) fluorene, 9,9-bis {(4-hydroxy-3-methyl) phenyl} fluorene, 9,9-bis {(4-hydroxy) −3,5-dimethyl) phenyl} fluorene, 9,9-bis {(4-hydroxy-3,5-dibromo) phenyl} fluorene, α, α′-bis (4-hydride) Xylphenyl) -o-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -m-diisopropylbenzene, α, α'-bis (4-hydroxyphenyl) -p-diisopropylbenzene, 4,4'-dihydroxy Examples include diphenyl sulfone, 4,4′-dihydroxydiphenyl ketone, and 4,4′-dihydroxydiphenyl ether, and these can be used alone or in admixture of two or more.

  A monohydric phenol compound may be used in combination to adjust the molecular weight to an appropriate range or to seal the hydroxyl terminal of the polymer chain. The monohydric phenol is not particularly limited as long as it is a compound that functions as a terminal blocking agent. For example, phenol, 4-tert-butylphenol, and 1-phenyl-1- (4-hydroxyphenyl) Examples include propane.

  Further, if necessary, a compound having UV absorbability such as 2- (2-hydroxy-3-t-butyl-5- (2-carboxyethyl)) phenylbenzotriazole may be used as the end-capping agent. .

  Polycarbonate resins can be easily obtained from commercial products. For example, “Lexan” (manufactured by SABIC Innovative Plastics), “Macrolon”, “Apec” (above, Bayer MaterialScience) "Iupilon", "Novax" (Mitsubishi Engineering Plastics Co., Ltd.), "Panlite" (manufactured by Teijin Chemicals Ltd.), "Caliber" (Dow Chemical Co., Ltd.), "SD Polyca" ( Sumitomo Dow Co., Ltd.) and “Toughlon” (Idemitsu Kosan Co., Ltd.).

(Norbornene resin)
Examples of the norbornene-based resin include a resin obtained by performing ring-opening metathesis polymerization using cyclopentadiene and olefins by a Diels-Alder reaction or a derivative thereof as a monomer, followed by hydrogenation; dicyclopentadiene and olefin Resins obtained by ring-opening metathesis polymerization using tetracyclododecene or a derivative thereof obtained by Diels-Alder reaction with aldehydes or methacrylates, followed by hydrogenation; norbornene, tetracyclododecene, those Derivatives, or resins obtained by subjecting other cyclic olefin monomers to ring-opening metathesis copolymerization followed by hydrogenation; and norbornene, tetracyclododecene, derivatives thereof, and vinyl groups Resins obtained by copolymerizing by addition polymerization of an aromatic compound having the like.

  Such a cyclic olefin-based resin can be easily obtained as a commercial product. For example, under the trade name, “Topas” (Topas Advanced Polymers GmbH), “Arton” (manufactured by JSR Corporation), “ZEONOR”, “ZEONEX” (manufactured by ZEON CORPORATION), “APEL” (manufactured by Mitsui Chemicals, Inc.), and the like.

(Silver reflection layer)
In the reflective plate for solar power generation of the present invention, a reflective film having a silver reflective layer provided on a film base on one side is laminated on the silver reflective layer surface side with a hard transparent resin substrate via an adhesive layer. The silver reflection layer surface is a reflection surface on the side where sunlight enters.

  As a method for forming the silver reflective layer provided on the film substrate of 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, an ion beam assisted vacuum deposition method, and a sputtering method. Etc. 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 reflective film having the silver reflective layer of the present invention on one side, a production method in which the silver reflective layer is formed by silver deposition is preferable.

  The thickness of the silver reflective layer provided on the film substrate is preferably 10 to 200 nm, more preferably 30 to 150 nm, from the viewpoint of reflectivity and the like.

(Film substrate)
Various conventionally known resin films can be used as the film substrate of the reflective film having the silver reflective layer of the present invention on one side. For example, polyester film such as polyethylene terephthalate, polyethylene naphthalate, cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose ester film such as cellulose acetate butyrate film, polycarbonate film, polyarylate film Polysulfone (including polyethersulfone) film, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, norbornene resin film, polymethylpentene film , Polyetherketone film, polyether Ketone imide film, polyamide film, fluorocarbon resin film, nylon film, such as polymethyl methacrylate film acrylic film. Among these, a polyester film, a cellulose ester film, a polycarbonate film, and a norbornene resin film are preferable.

  In particular, it is preferable to use a polyester film, a cellulose ester film, or a polycarbonate film as a film base material, and even a film manufactured by melt casting is a film manufactured by solution casting. May be.

  In the production of the film substrate, if necessary, known additives such as plasticizers, antistatic agents, lubricants, antioxidants described later, ultraviolet absorbers and light stabilizers are optionally added and kneaded. Then, it may be formed into a film.

  As long as the effects of the present invention are not hindered, the functional layer can be laminated on one side or both sides of the film base. Examples of the functional layer to be laminated include a conductive layer, a hard coat layer, a smoothing layer, an easy-sliding layer, an anti-blocking layer, and an easy-adhesion layer.

  As for the thickness of the said film base material, 10-300 micrometers is preferable, More preferably, it is 20-200 micrometers.

  The film substrate may be a stretched film, and as a stretching method, for example, uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, etc. can be performed. The roll type uniaxial stretching machine, the tenter type horizontal stretching machine, the tenter type or the tubular type biaxial stretching machine can be used for stretching.

  A particularly preferred type of film is a polyethylene terephthalate film, the details of which are described below.

(Polyethylene terephthalate film)
The polyethylene terephthalate film preferably used in the present invention is a film formed by melt extrusion of one or more polyethylene terephthalate resins, one or more uniaxially stretched films formed by transverse stretching, or longitudinally stretched after film formation, Next, it is a biaxially stretched film of one or more layers that is laterally stretched.

  The polyethylene terephthalate resin means a resin in which 80 mol% or more of repeating units are composed of ethylene terephthalate, and may contain other dicarboxylic acid components and diol components. Examples of other dicarboxylic acid components include, but are not limited to, isophthalic acid, p-β-oxyethoxybenzoic acid, 4,4′-dicarboxydiphenyl, 4,4′-dicarboxybenzophenone, bis (4-Carboxyphenyl) ethane, adipic acid, sebacic acid, 1,4-dicarboxycyclohexane and the like can be mentioned. Other diol components are not particularly limited, but propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Etc. These other dicarboxylic acid components and other diol components can be used in combination of two or more if necessary. Moreover, oxycarboxylic acids, such as p-oxybenzoic acid, can also be used together. Further, as other copolymerization component, a dicarboxylic acid component or a diol component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like may be used.

  The molecular weight of the polyethylene terephthalate resin is usually 0.45 to 1.0 dL when the resin is dissolved in a mixed solvent of phenol / tetrachloroethane = 50/50 (mass ratio) and expressed in terms of intrinsic viscosity measured at 30 ° C. / G, preferably 0.50 to 1.0 dL / g, more preferably 0.52 to 0.80 dL / g.

  Further, the polyethylene terephthalate resin can contain an additive as required. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antistatic agent, an impact resistance improver, an antioxidant, an ultraviolet absorber, and a light stabilizer described later. The addition amount is preferably kept in a range that does not adversely affect the optical properties.

  Polyethylene terephthalate-based resins are usually used in the form of pellets granulated by an extruder for blending such additives and for film formation described later. The size and shape of the pellet are not particularly limited, but are usually cylindrical, spherical or flat spherical with a height and diameter of 5 mm or less. The polyethylene terephthalate-based resin thus obtained can be made into a transparent and homogeneous polyethylene terephthalate film having high mechanical strength by forming into a film and stretching. Although the manufacturing method is not particularly limited, for example, the following method is adopted.

  First, dried pellets made of polyethylene terephthalate resin are supplied to a melt extrusion apparatus and heated to a melting point or higher to melt. Next, the melted resin is extruded from a die and rapidly cooled and solidified on the rotary cooling drum so that the temperature is equal to or lower than the glass transition temperature to obtain a substantially amorphous unstretched film. The melting temperature is determined according to the melting point of the polyethylene terephthalate resin to be used and the extruder, and is not particularly limited, but is usually 250 to 350 ° C.

  Further, in order to improve the flatness of the film, it is preferable to improve the adhesion between the film and the rotary cooling drum, and an electrostatic application adhesion method or a liquid application adhesion method is preferably employed. In the electrostatic application adhesion method, a linear electrode is usually stretched in the direction perpendicular to the film flow on the upper surface side of the film, and a static voltage is applied to the film by applying a DC voltage of about 5 to 10 kV to the electrode. This is a method for improving the adhesion between the rotary cooling drum and the film. Also, the liquid application adhesion method improves the adhesion between the rotating cooling drum and the film by uniformly applying the liquid to the entire surface of the rotating cooling drum or a part of it (for example, only the portion that contacts both ends of the film). It is a method to make it. You may use both together as needed. The polyethylene terephthalate resin to be used may be mixed with two or more kinds of resins having different resin structures and compositions as necessary. For example, it is possible to use a mixture of a particulate filler as an antiblocking agent or a pellet containing an antistatic agent and a non-compounding pellet.

  Moreover, the number of laminated films may be two or more if necessary. For example, a pellet containing a granular filler as an antiblocking agent and a non-compounded pellet are prepared and supplied to the same die from different extruders, consisting of two types and three layers of “filler blend / no blend / filler blend”. For example, extruding a film.

  The unstretched film is usually first stretched in the extrusion direction at a temperature equal to or higher than the glass transition temperature. The stretching temperature is usually 70 to 150 ° C, preferably 80 to 130 ° C, and more preferably 90 to 120 ° C. The draw ratio is preferably 1.1 times or more and 6 times or less. This stretching can be completed once or divided into a plurality of times as necessary. Usually, even when stretching is performed a plurality of times, the total stretching ratio is preferably within the above range.

  The longitudinally stretched film thus obtained can then be heat treated. Then, if necessary, relaxation treatment can be performed. This heat treatment temperature is usually 150 to 250 ° C, preferably 180 to 245 ° C, more preferably 200 to 230 ° C. The heat treatment time is usually 1 to 600 seconds, preferably 1 to 300 seconds, and more preferably 1 to 60 seconds.

  When obtaining a uniaxially stretched film and a biaxially stretched film, the transverse stretching is usually performed by a tenter after the longitudinal stretching process or after a heat treatment or a relaxation process as necessary. This stretching temperature is usually 70 to 150 ° C, preferably 80 to 130 ° C, and more preferably 90 to 120 ° C. The draw ratio is preferably 1.1 times or more and 6 times or less.

  In the stretched polyethylene terephthalate film preferably used in the present invention, a functional layer can be laminated on one side or both sides as long as the effects of the present invention are not hindered. Examples of the laminated functional layer include a conductive layer, a hard coat layer, a smoothing layer, an easy-sliding layer, an anti-blocking layer, and an easy-adhesion layer. Among these, the stretched polyethylene terephthalate film is preferably laminated with an easy adhesion layer.

  The component constituting the easy-adhesion layer is not particularly limited. For example, a polyester resin, a urethane resin, or an acrylic resin having a polar group in the skeleton and a relatively low molecular weight and a low glass transition temperature. Examples thereof include resins. Moreover, a crosslinking agent, an organic or inorganic filler, a surfactant, a lubricant and the like can be contained as necessary.

  The method of forming the functional layer into a stretched polyethylene terephthalate film is not particularly limited, but for example, a method of forming a film after all stretching steps, during a step of stretching a polyethylene terephthalate resin, For example, a method of forming between the longitudinal stretching and the lateral stretching process is employed. Among these, from the viewpoint of productivity, a method in which a polyethylene terephthalate-based resin is formed after being longitudinally stretched and then stretched laterally is preferably employed.

  The stretched polyethylene terephthalate film thus obtained can be easily obtained as a commercial product. For example, “Diafoil”, “Hostafan”, “Fusion” (above, manufactured by Mitsubishi Plastics, Inc.) ), "Teijin Tetron Film", "Melinex", "Mylar", "Teflex" (Teijin DuPont Films Ltd.), "Toyobo Ester Film", "Toyobo Espet Film", "Cosmo Shine" “Chrisper” (manufactured by Toyobo Co., Ltd.), “Lumirror” (manufactured by Toray Film Processing Co., Ltd.), “Embron”, “Embret” (manufactured by Unitika Ltd.), “Skyroll” (SKC) ) “Cofil” (manufactured by Kogo Co., Ltd.), “Zuitsu Polyester Film” (Zui Co., Ltd.) Etsu Chemical Co., Ltd.), and "Taiko polyester film" (manufactured by Futamura Chemical Co., Ltd.), and the like. Among these, from the viewpoints of productivity and inexpensiveness, a biaxially stretched product is preferably used in the present invention.

(Adhesive layer)
In the present invention, the adhesive layer is provided between the hard transparent resin substrate and the reflective film having the silver reflective layer on one side. The adhesive layer is not particularly limited as long as it has a function of improving the adhesion between the transparent resin substrate and the reflective film having the silver reflective layer on one side, but is preferably made of a resin. Moreover, this adhesion layer can be used for enhancing the adhesion between the silver protective layer and / or the barrier layer further formed on the silver reflection layer and the transparent resin substrate. It is preferable to consist of resin.

  The resin used as the binder for the adhesive layer is not particularly limited as long as it satisfies the conditions of adhesiveness, weather resistance, transparency, and smoothness. Polyurethane resin, polyester resin, acrylic resin, melamine Resin, epoxy resin, polyamide resin, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin, etc. can be used singly or as a mixed resin. From the viewpoint of weather resistance and adhesiveness, polyurethane resin, polyester resin can be used. A resin or a melamine-based resin is preferable, and a thermosetting resin in which a curing agent such as isocyanate is further mixed is more preferable. Particularly preferably, a polyurethane resin is contained.

  The thickness of the adhesive layer is preferably from 0.01 to 30 μm, more preferably from 0.1 to 15 μm, from the viewpoints of adhesiveness, smoothness, reflectance of the reflecting material, and the like.

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

  The adhesive layer may contain a silver corrosion inhibitor described later, an antioxidant described later, an ultraviolet absorber, a light stabilizer, and the like according to the purpose.

  A commercially available adhesive can be used for the adhesive layer, but there is no particular limitation as long as it satisfies the conditions of adhesiveness, weather resistance, transparency, and smoothness.

  As a method of laminating a hard transparent resin substrate and a reflective film having a silver reflective layer on one side via an adhesive layer, a method similar to the laminating method used when producing a packaging material can be used. For example, it can be carried out by a method such as dry lamination (including solventless type, wax hot melt type, etc.), wet lamination, extrusion lamination, inflation laminating method and the like. In the above lamination, for example, an organic titanium anchor coating agent, an isocyanate anchor coating agent (urethane type), an anchor coating agent for lamination such as a polyethyleneimine anchor coating agent, or a polyurethane adhesive, a polyester adhesive, Epoxy adhesives, polyvinyl acetate adhesives, polyvinyl chloride-vinyl acetate copolymer adhesives, melt adhesives such as polyacrylic adhesives, emulsions such as polyvinyl acetate emulsions and polyacrylic resin emulsions Various adhesives such as an adhesive, an ultraviolet ray or an electron beam curable adhesive can be used. In the present invention, when the resin film is itself self-adhesive by heat melting or the like, a laminate sheet can be manufactured by laminating without using the above-mentioned adhesive. In this case, itself may be regarded as an adhesive. In the present invention, prior to lamination, a known pretreatment such as corona treatment or ozone treatment can be applied to the surface of the film in advance. At the time of pasting, methods such as dry lamination, solventless lamination, and wet lamination described in industrial plastic films (Tomoyuki Minami, Atsushi Kosada, published by CTI Processing Technology Study Group 1991) can also be used.

  The lamination method is preferably manufactured by a single wafer type, and the process operation is performed on a hard transparent resin substrate having excellent smoothness, so that smoothness is maintained throughout the entire process, and there is no variation in the quality of the finished product, and the yield is also high. Improve dramatically. Further, since it can be manufactured in a single wafer type on a hard transparent resin base plate, it is possible to manufacture with a very compact facility. Therefore, manufacturing space and incidental equipment space can be reduced, and resources such as electric power and chemicals can be saved, and lead time can be shortened.

(Silver protective layer)
The solar heat reflecting plate of the present invention preferably has a silver protective layer on the surface of the silver reflecting layer of the reflecting film having the silver reflecting layer provided on the film base on one side.

  The silver protective layer is used for protecting the silver reflective layer formed on the film substrate until it is laminated on the hard transparent resin substrate, and is preferably a transparent coating. The coating liquid used for forming the protective layer is not particularly limited. That is, any known material may be used as long as it meets the object of the present invention, but after coating or coating, the transparency of the coating film is 80% or more, heat resistance, weather resistance, corrosion resistance and salt water resistance. Those excellent in the above are preferred.

  The silver protective layer preferably used in the present invention is adjacent to the silver reflective layer, and preferably contains a silver corrosion inhibitor, which will be described later, to prevent corrosion deterioration of the silver, to prevent scratches on the silver reflective layer, and to the outside of the silver protective layer. It contributes to the improvement of the adhesive strength with the barrier layer and the scratch-preventing layer.

  The resin used as a binder for the silver protective layer can be a polyester resin, an acrylic resin, a melamine resin, an epoxy resin, or a mixture of these resins. From the viewpoint of weather resistance, a polyester resin or an acrylic resin can be used. A resin is preferable, and a thermosetting resin in which a curing agent such as isocyanate is further mixed is more preferable. Isocyanate is a mixture of one or more of various conventionally used isocyanates such as TDI (tolylene diisocyanate), XDI (xylene diisocyanate), MDI (methylene diisocyanate), and HMDI (hexamethylene diisocyanate). Can be used. Moreover, it is preferable to further mix a silane coupling agent with the thermosetting resin because weather resistance is further improved. Of these, mixing a silane coupling agent having an amino group is more preferable from the viewpoint of weather resistance.

  The thickness of the silver protective layer is preferably from 0.1 to 20 μm, more preferably from 1 to 10 μm, from the viewpoints of adhesion, weather resistance and the like.

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

  Further, it is preferable to use a silver corrosion inhibitor described later, an antioxidant described later, a light stabilizer described later, and an ultraviolet absorber described later for the silver protective layer, for example, TINUVIN series, IRGANOX series and Chimassorb series or the like can be used.

(Silver corrosion inhibitor)
The solar heat reflecting plate of the present invention preferably contains a silver corrosion inhibitor in at least one of the constituent layers. Here, “corrosion” refers to a phenomenon in which silver is chemically or electrochemically eroded or materially deteriorated by an environmental material surrounding it (see JIS Z0103-2004).

  It is preferable that the said corrosion inhibitor is an aspect containing the corrosion inhibitor or antioxidant which has an adsorptive group with respect to 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 preferably selected from at least one of a ring-containing compound, a copper chelate compound, a thiourea, a mercapto group-containing compound, a naphthalene-based compound, or a mixture thereof.

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

  Examples of the compound having a pyrrole ring include N-butyl-2,5-dimethylpyrrole, N-phenyl-2,5-dimethylpyrrole, N-phenyl-3-formyl-2,5-dimethylpyrrole, and N-phenyl-3. , 4-diformyl-2,5-dimethylpyrrole, 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) 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-form Ruimidazole, 4-methyl-5-formylimidazole, 2-ethyl-4-methyl-5-formylimidazole, 2-phenyl-4-methyl-4-formylimidazole, 2-mercaptobenzimidazole, etc., or a mixture thereof. Can be 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 copper chelate compounds include acetylacetone copper, ethylenediamine copper, phthalocyanine copper, ethylenediaminetetraacetate copper, hydroxyquinoline copper, and mixtures 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, butanediol bisthioglycol, trimethylolpropane tristhioglycolate, pentaerythritol Examples include tetrakisthioglycolate, trimethylolpropane tristhiopropionate, pentaerythritol tetrakisthiopropionate, triethylene glycol dimercaptan, and the like, or a mixture thereof.

  Examples of the naphthalene type include thionalide.

  As the corrosion inhibitor for the silver reflective layer used in the present invention, a compound functioning as an ultraviolet absorber described later can also be used.

(Antioxidant)
The solar heat reflector of the present invention preferably contains an antioxidant in at least one of the constituent layers. Preferable antioxidants include phenolic antioxidants, thiol antioxidants, and phosphite antioxidants.

  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.

(Light stabilizer)
The solar heat reflecting plate of the present invention preferably contains a light stabilizer in at least one of the constituent layers. Examples of the hindered amine light stabilizer preferably used in the present invention include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate and 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-butylmalo 1-methyl-8- (1,2,2,6,6-pentamethyl-4-piperidyl) -sebacate, 1- [2- [3- (3,5-di-t-butyl-4-hydroxy) Phenyl) propionyloxy] ethyl] -4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -2,2,6,6-tetramethylpiperidine, 4-benzoyloxy- , 2,6,6-tetramethylpiperidine, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butane-tetracarboxylate, triethylenediamine, 8-acetyl- Examples include 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)
The solar heat reflector of the present invention preferably contains an ultraviolet absorber in at least one of the constituent layers. Examples of the ultraviolet absorber preferably used in the present invention include benzophenone-based, benzotriazole-based, phenyl salicylate-based, or triazine-based compounds.

  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 or a colorant can be used together. 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%.

(Barrier layer)
The solar heat reflector of the present invention preferably has a barrier layer.

  The barrier layer is intended to prevent deterioration of humidity, especially deterioration of the resin base material and various functional elements protected by the resin base material due to high humidity, but with special functions and applications. As long as the above characteristics are maintained, various types of barrier layers can be provided. In the present invention, it is preferable to provide a barrier layer on the light source side of the silver reflective layer.

As the moisture resistance of the barrier layer, the water vapor permeability at 40 ° C. and 90% RH is 100 g / m ² · day / μm or less, preferably 50 g / m ² · day / μm or less, more preferably 20 g / m ² · It is preferable to adjust the moisture resistance of the barrier layer so as to be not more than day / μm. The oxygen permeability is 0.6 cm ³ / m ² / day / atm or less (1 atm is 1.01325 × 10 ⁵ Pa) under the conditions of a measurement temperature of 23 ° C. and a humidity of 90% RH. It is preferable.

  Regarding the barrier layer, there is no particular limitation on the formation method thereof, but a method of forming an inorganic oxide film by applying a ceramic precursor of an inorganic oxide film and then heating and / or irradiating ultraviolet rays is preferably used. It is done.

(Ceramic precursor)
The barrier layer 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.

(Organic metal compound)
The organometallic compounds are silicon (Si), aluminum (Al), lithium (Li), zirconium (Zr), titanium (Ti), tantalum (Ta), zinc (Zn), barium (Ba), indium (In), It is preferable to contain at least one element of tin (Sn), lanthanum (La), yttrium (Y), and niobium (Nb). In particular, the organometallic compound is at least one element of silicon (Si), aluminum (Al), lithium (Li), zirconium (Zr), titanium (Ti), zinc (Zn), and barium (Ba). It is preferable to contain. Furthermore, it is preferable to contain at least one element of silicon (Si), aluminum (Al), and lithium (Li).

  The organometallic compound is not particularly limited as long as it can be hydrolyzed, and preferred organometallic compounds include metal alkoxides.

  The metal alkoxide is represented by the following general formula (I).

Formula (I): MR ² _m (OR ¹ ) _(nm)
In the general formula (I), M represents a metal having an oxidation number n. R ¹ and R ² each independently represents an alkyl group. m represents an integer of 0 to (n-1). R ¹ and R ² may be the same or different. R ¹ and R ² are preferably alkyl groups having 4 or less carbon atoms, for example, a methyl group CH ₃ (hereinafter represented by Me), an ethyl group C ₂ H ₅ (hereinafter represented by Et), a propyl group. C ₃ H ₇ (hereinafter represented by Pr), isopropyl group i-C ₃ H ₇ (hereinafter represented by i-Pr), butyl group C ₄ H ₉ (hereinafter represented by Bu), isobutyl group i- Lower alkyl groups such as C ₄ H ₉ (hereinafter represented by i-Bu) are more preferred.

Examples of the metal alkoxide represented by the general formula (I) include lithium ethoxide LiOEt, niobium ethoxide Nb (OEt) ₅ , magnesium isopropoxide Mg (OPr-i) ₂ , aluminum isopropoxide Al (OPr -I) ₃ , zinc propoxide Zn (OPr) ₂ , tetraethoxysilane Si (OEt) ₄ , titanium isopropoxide Ti (OPr-i) ₄ , barium ethoxide Ba (OEt) ₂ , barium isopropoxide Ba ( OPr-i) ₂ , triethoxyborane B (OEt) ₃ , zirconium propoxide Zn (OPr) ₄ , lanthanum propoxide La (OPr) ₃ , yttrium propoxide Y (OPr) ₃ , lead isopropoxide Pb (OPr- i) ₂ etc. are mentioned suitably. All of these metal alkoxides are commercially available and can be easily obtained. Moreover, the metal alkoxide is also commercially available as a low condensate obtained by partial hydrolysis, and can be used as a raw material.

(Inorganic oxide)
The inorganic oxide is preferably formed from a sol using the organometallic compound as a raw material by local heating. Therefore, silicon (Si), aluminum (Al), zirconium (Zr), titanium (Ti), tantalum (Ta), zinc (Zn), barium (Ba), indium (In) contained in the organometallic compound, An oxide of an element such as tin (Sn) or niobium (Nb) is preferable.

  For example, silicon oxide, aluminum oxide, zirconium oxide and the like. Of these, silicon oxide is preferable.

  As a method of forming an inorganic oxide from an organometallic compound, it is preferable to use a so-called sol-gel method and a method of applying polysilazane.

(Sol-gel method)
Here, the “sol-gel method” is to obtain a hydroxide sol by hydrolyzing an organometallic compound, etc., dehydrate it into a gel, and further heat-treat this gel. It refers to a method for preparing a metal oxide glass having a certain shape (film, particle, fiber, etc.). A multi-component metal oxide glass can be obtained by a method of mixing a plurality of different sol solutions, a method of adding other metal ions, or the like.

  Specifically, it is preferable to produce an inorganic oxide by a sol-gel method having the following steps.

  That is, in a reaction solution containing at least water and an organic solvent, the organometallic compound is hydrolyzed and dehydrated and condensed while adjusting the pH to 4.5 to 5.0 using a halogen ion as a catalyst in the presence of boron ion. Generation of micropores due to high-temperature heat treatment is produced by a sol-gel method having a step of obtaining a reaction product by heating and vitrifying the reaction product at a temperature of 200 ° C. or lower. And is particularly preferable from the viewpoint that no deterioration of the film occurs.

  In the sol-gel method, the organometallic compound used as a raw material is not particularly limited as long as it can be hydrolyzed, and a preferable organometallic compound includes the metal alkoxide. .

  In the sol-gel method, the organometallic compound may be used for the reaction as it is, but it is preferably diluted with a solvent for easy control of the reaction. The solvent for dilution is not particularly limited as long as it can dissolve the organometallic compound and can be uniformly mixed with water. Preferred examples of such a solvent for dilution include aliphatic lower alcohols such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol, and mixtures thereof. A mixed solvent of butanol, cellosolve, and butyl cellosolve, or a mixed solvent of xylol, cellosolve acetate, methyl isobutyl ketone, and cyclohexane can also be used.

In the organometallic compound, when the metal is Ca, Mg, Al, etc., it reacts with water in the reaction solution to produce a hydroxide, or when carbonate ion CO ₃ ^2- is present, produces a carbonate. Therefore, it is preferable to add an alcohol solution of triethanolamine as a masking agent to the reaction solution. The concentration of the organometallic compound when mixed and dissolved in a solvent is preferably 70% by mass or less, and more preferably diluted to a range of 5 to 70% by mass.

  The reaction liquid used in the sol-gel method contains at least water and an organic solvent. The organic solvent is not particularly limited as long as it can form a uniform solution with water, acid, and alkali, and usually the same aliphatic lower alcohols used for diluting the organometallic compound are preferably used. Among the aliphatic lower alcohols, propanol, isopropanol, butanol, and isobutanol having a larger number of carbon atoms are preferable to methanol and ethanol. This is because the growth of the metal oxide glass film to be generated is stable. In the reaction solution, the water ratio is preferably in the range of 0.2 to 50 mol / L as the water concentration.

In the sol-gel method, an organometallic compound is hydrolyzed in the reaction solution using a halogen ion as a catalyst in the presence of boron ions. Preferred examples of the compound that gives the boron ion B ³⁺ include trialkoxyborane B (OR) ₃ . Among these, triethoxyborane B (OEt) ₃ is more preferable. In addition, the B ³⁺ ion concentration in the reaction solution is preferably in the range of 1.0 to 10.0 mol / L.

As said halogen ion, a fluorine ion and / or a chlorine ion are mentioned suitably. That is, fluorine ions alone, chlorine ions alone or a mixture thereof may be used. The compound to be used may be any compound that generates fluorine ions and / or chlorine ions in the reaction solution. For example, as the fluorine ion source, ammonium hydrogen fluoride NH ₄ HF · HF, sodium fluoride NaF, or the like is preferable. Preferred examples of the chlorine ion source include ammonium chloride NH ₄ Cl.

  The concentration of the halogen ions in the reaction solution varies depending on the film thickness of an inorganic composition having an inorganic matrix to be produced and other conditions, but generally the reaction solution containing a catalyst. Is preferably in the range of 0.001 to 2 mol / kg, particularly 0.002 to 0.3 mol / kg. If the halogen ion concentration is lower than 0.001 mol / kg, hydrolysis of the organometallic compound does not proceed sufficiently, and film formation becomes difficult. If the halogen ion concentration exceeds 2 mol / kg, the resulting inorganic matrix (metal oxide glass) tends to be non-uniform, which is not preferable.

With respect to the boron used during the reaction, if to be contained as a B ₂ O ₃ component in the design the composition of the resulting inorganic matrix, by leaving product was added calculated amount of organic boron compound in accordance with the content of In addition, when it is desired to remove boron, boron can be removed by evaporation as boron methyl ester after film formation in the presence of methanol as a solvent, or by immersion in methanol and heating.

  In the step of hydrolyzing and dehydrating and condensing the organometallic compound to obtain a reaction product, a main agent solution in which a predetermined amount of the organometallic compound is usually mixed and dissolved in a mixed solvent containing a predetermined amount of water and an organic solvent, In addition, a predetermined amount of the reaction solution containing a predetermined amount of the above halogen ions is mixed at a predetermined ratio and sufficiently stirred to obtain a uniform reaction solution, and then the pH of the reaction solution is adjusted to a desired value with acid or alkali. The reaction product is obtained by aging for several hours. A predetermined amount of the boron compound is mixed and dissolved in advance in the main agent solution or reaction solution. When alkoxyborane is used, it is advantageous to dissolve it in the main agent solution together with other organometallic compounds.

  The pH of the reaction solution is selected depending on the purpose, and for the purpose of forming a film (film) made of an inorganic composition having an inorganic matrix (metal oxide glass), for example, the pH is adjusted using an acid such as hydrochloric acid. It is preferable to ripen by adjusting to a range of 4.5-5. In this case, for example, it is convenient to use a mixture of methyl red and bromocresol green as an indicator.

In the sol-gel method, the main component solution of the same concentration of the same component and the reaction solution (including B ³⁺ and halogen ions) are successively added at the same rate while adjusting to a predetermined pH. The reaction product can also be produced simply and continuously. The concentration of the reaction solution is in the range of ± 50% by mass, the concentration of water (including acid or alkali) is in the range of ± 30% by mass, and the concentration of halogen ions is in the range of ± 30% by mass. Can be changed.

  Next, the reaction product (reaction solution after aging) obtained in the previous step is heated to a temperature of 200 ° C. or lower, dried and vitrified. In heating, it is preferable to raise the temperature gradually after paying attention to a temperature range of 50 to 70 ° C., followed by a preliminary drying (solvent volatilization) step. This drying is important for forming a non-porous film in the case of film formation. The temperature for heating and drying after the preliminary drying step is preferably 70 to 150 ° C, more preferably 80 to 130 ° C.

(Method of applying polysilazane)
It is also preferred that the barrier layer contains an inorganic oxide formed by local heating of the coating film after the ceramic precursor that forms the inorganic oxide film is applied by heating.

  When the ceramic precursor contains polysilazane, the resin substrate is coated with a solution containing a catalyst in polysilazane represented by the following general formula (II) and an organic solvent as necessary, and the solvent is evaporated. Leaving a polysilazane layer having a layer thickness of 0.05 to 3.0 μm on the resin substrate and the presence of oxygen, active oxygen, and in some cases, nitrogen in an atmosphere containing water vapor Below, it is preferable to employ | adopt the method of forming a glass-like transparent film on the said resin base material by locally heating said polysilazane layer.

Formula (II):-(SiR ¹¹ (R ¹² ) -NR ¹³ ) _n11-
In which R ¹¹ , R ¹² and R ¹³ are the same or different and independently of one another hydrogen or a substituted alkyl group, aryl group, vinyl group or (trialkoxysilyl) alkyl group, preferably hydrogen, A group selected from the group consisting of methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, tert-butyl, phenyl, vinyl or 3- (triethoxysilyl) propyl, 3- (trimethoxysilylpropyl) Where n11 is an integer and n11 is defined such that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol.

  As catalysts, preferably basic catalysts, in particular N, N-diethylethanolamine, N, N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine or N-heterocyclic compounds are used. . The catalyst concentration is usually in the range of 0.1 to 10 mol%, preferably 0.5 to 7 mol%, based on polysilazane.

In one of the preferable embodiments, a solution containing perhydropolysilazane in which all of R ¹¹ , R ¹² , and R ¹³ are hydrogen atoms is used.

  In yet another preferred embodiment, the coating according to the invention comprises at least one polysilazane of the general formula (III).

Formula ^{(III) :-( SiR 21 R 22} -NR 23) n21 - (SiR 24 R 25 -NR 26) p21 -
In the formula, R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ and R ²⁶ each independently represent hydrogen or a substituted alkyl group, aryl group, vinyl group or (trialkoxysilyl) alkyl group. In this case, n21 and p21 are integers, and n21 is determined so that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol.

Particularly preferred are compounds wherein R ²¹ , R ²³ and R ²⁶ represent hydrogen and R ²² , R ²⁴ and R ²⁵ represent methyl, R ²¹ , R ²³ and R ²⁶ represent hydrogen, and R ²² , A compound in which R ²⁴ represents methyl and R ²⁵ represents vinyl, R ²¹ , R ²³ , R ²⁴ and R ²⁶ represent hydrogen and R ²² and R ²⁵ represent methyl.

  Likewise preferred are solutions containing at least one polysilazane of the general formula (IV).

Formula ^{(IV) :-( SiR 31 R 32} -NR 33) n31 - (SiR 34 R 35 -NR 36) p31 - (SiR 37 R 38 -NR 39) q31 -
In the formula, R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ , R ³⁶ , R ³⁷ , R ³⁸ and R ³⁹ are independently of each other hydrogen or a substituted alkyl group, aryl group, vinyl group or Represents a (trialkoxysilyl) alkyl group, wherein n31, p31 and q31 are integers, and n31 is determined so that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol.

Particularly preferred are R ³¹ , R ³³ and R ³⁶ representing hydrogen and R ³² , R ³⁴ , R ³⁵ and R ³⁸ representing methyl, R ³⁹ representing (triethoxysilyl) propyl and R ³⁷ Is a compound in which represents alkyl or hydrogen.

  The ratio of polysilazane in the solvent is generally 1 to 80% by mass of polysilazane, preferably 5 to 50% by mass, and particularly preferably 10 to 40% by mass.

  As the solvent, in particular, an aprotic solvent which does not contain water and a reactive group (for example, hydroxyl group or amine group) and is inert to polysilazane, preferably an aprotic solvent is suitable. This includes, for example, aliphatic or aromatic hydrocarbons, halogen hydrocarbons, esters such as ethyl acetate or butyl acetate, ketones such as acetone or methyl ethyl ketone, ethers such as tetrahydrofuran or dibutyl ether, and mono- and polyalkylene glycol dialkyl ethers. (Diglymes) or a mixture of these solvents.

  An additional component of the polysilazane solution can be a further binder such as those conventionally used in the manufacture of paints. For example, cellulose ethers and cellulose esters such as ethyl cellulose, nitrocellulose, cellulose acetate or cellulose acetobutyrate, natural resins such as rubber or rosin resins, or synthetic resins such as polymerized resins or condensed resins such as aminoplasts, in particular Urea resins and melamine formaldehyde resins, alkyd resins, acrylic resins, polyesters or modified polyesters, epoxides, polyisocyanates or blocked polyisocyanates, or polysiloxanes.

Further components of the polysilazane formulation, for example, the viscosity of the formulation, wetting the underlying film-forming property, additives that affect lubrication or exhaust resistance, or inorganic nanoparticles, for example SiO 2, _{TiO 2,} ZnO , ZrO ₂ or Al ₂ O ₃ .

  By using polysilazane, it is possible to produce a dense glass-like layer having excellent barrier action against gas because there are no cracks and holes.

  The thickness of the film to be formed is preferably in the range of 100 nm to 2 μm.

(Scratch prevention layer)
In the present invention, it is preferable to provide a scratch preventing layer as the outermost layer of the solar power generation reflector.

  The scratch preventing layer can be composed of an acrylic resin, a urethane resin, a melamine resin, an epoxy resin, an organic silicate compound, a silicone resin, or the like. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability. Furthermore, what consists of an active energy ray hardening-type acrylic resin or a thermosetting type acrylic resin is preferable at the point of sclerosis | hardenability, flexibility, and productivity.

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

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

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

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

  In the present invention, various additives can be further blended in the scratch-preventing layer as necessary within the range where the effects of the present invention are not impaired. For example, stabilizers such as antioxidants, light stabilizers, ultraviolet absorbers, surfactants, leveling agents, antistatic agents, and the like can be used.

  The leveling agent is particularly effective in reducing surface irregularities when a scratch-preventing 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.

(Total thickness of solar power reflector)
The total thickness of the solar power generation reflector according to the present invention is preferably 0.2 to 30 mm, more preferably 0.5 to 20 mm, from the viewpoints of deflection prevention, regular reflectance, handling properties, and the like.

(Reflector for solar thermal power generation)
The reflector for solar power generation of the present invention can be preferably used for the purpose of concentrating sunlight. Although the reflector for solar power generation of the present invention can be used as a reflector for solar power generation, more preferably, the reflector for solar power generation is coated on the film base surface opposite to the side having the silver reflection layer. It is preferably formed by being attached to a holding member via an adhesive layer. In particular, it is preferably formed by pasting on a metal substrate.

  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 which heats an internal fluid by this, converts the heat energy, and generates electric power is mentioned as one form. In addition, flat reflectors were installed at a plurality of locations, and the sunlight reflected by each reflector was collected on one reflector (central reflector) and reflected by the reflector. The form which generate | occur | produces electricity by converting a 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 used, the reflection device for solar power generation of the present invention is particularly preferably used.

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

Preferably, an adhesive is used, and as the main resin, for example, a polyester resin, a urethane resin, a polyvinyl acetate resin, an acrylic resin, a nitrile rubber, or the like is used. Among them, a preferable pressure-sensitive adhesive is acrylic. Specifically, radical polymerization of an acrylic monomer composition containing a (meth) acrylic acid ester as a main component and a small amount of a (meth) acrylic monomer having a functional group in the presence of a polymerization initiator is performed. And an acrylic pressure-sensitive adhesive containing an acrylic resin having a glass transition temperature (Tg) of 0 ° C. or lower and a crosslinking agent. Here, the (meth) acrylic acid ester as the main component of the acrylic resin has the following formula:
CH ₂ = C (R ^1N ) COOR ^2N
In the formula, R ^1N represents a hydrogen atom or a methyl group, R ^2N represents an alkyl group having 1 to 14 carbon atoms or an aralkyl group, and a hydrogen atom or an aralkyl group of an alkyl group of R ^2N The hydrogen atom may be substituted with an alkoxy group having 1 to 10 carbon atoms.

  The (meth) acrylic monomer having a functional group has a polar functional group such as a hydroxyl group, a carboxyl group, an amino group, and an epoxy group and one olefinic double bond (usually a (meth) acryloyl group) in the molecule. The monomer to contain is preferable.

If the specific example of the (meth) acrylic acid ester which becomes the main component of acrylic resin is given, for example, R ^1N is H, R ^2N is n-butyl group, butyl acrylate, R ^1N is H And 2-ethylhexyl acrylate in which R ^2N is a 2-ethylhexyl group. Further, specific examples of the (meth) acrylic monomer having a functional group include, for example, 2-hydroxyethyl (meth) acrylate having a hydroxyl group; acrylic acid having a carboxyl group. Furthermore, in the production of this acrylic resin, a small amount of a monomer having a plurality of (meth) acryloyl groups in the molecule can be copolymerized. Examples thereof include 1,4-butanediol di (meth) acrylate and the like. It is done.

  In the production of the acrylic resin, only one type of the (meth) acrylic acid ester and the (meth) acrylic monomer having a functional group may be used, or a plurality of types may be used in combination. In addition, a combination of a plurality of acrylic resins that are copolymers of (meth) acrylic acid esters and (meth) acrylic monomers having functional groups, or other acrylic resins that are copolymers of the acrylic resins For example, an acrylic resin composition obtained by blending an acrylic resin composed of a single or copolymer of a (meth) acrylic monomer having no functional group, or the like can be used as a resin component of the pressure-sensitive adhesive.

  The crosslinking agent blended in the acrylic pressure-sensitive adhesive can be an isocyanate compound, an epoxy compound, a metal chelate compound, an aziridine compound, or the like. Isocyanate compounds should be used in the form of adducts, dimers, trimers, etc., in which the compounds have at least two isocyanato groups (—NCO) in the molecule, as well as those reacted with polyols. Can do. As specific examples of the crosslinking agent, there are a trimethylolpropane adduct of hexamethylene diisocyanate and a trimethylolpropane adduct of tolylene diisocyanate as diisocyanate compounds, each used as a solution dissolved in an organic solvent such as ethyl acetate. There are many cases. These crosslinking agents may be used alone or in combination of two or more.

  The weight average molecular weight of the acrylic resin contained in the acrylic pressure-sensitive adhesive is preferably 600,000 to 2,000,000 in terms of standard polystyrene using gel permeation chromatography (GPC).

  The acrylic resin is dissolved in an organic solvent such as ethyl acetate, and a crosslinking agent is added to obtain an acrylic pressure-sensitive adhesive solution. If necessary, a silane coupling agent, a weather stabilizer, a tackifier, a plasticizer, a softener, a pigment, and one or more inorganic fillers, and further light diffusing fine particles such as organic beads are included. be able to.

  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 1 to 50 μm from the viewpoints of pressure-sensitive adhesive effect, drying speed, and the like.

  The acrylic pressure-sensitive adhesive solution thus obtained is usually coated on a release film, heated at 60 to 120 ° C. for about 0.5 to 10 minutes, and the organic solvent is distilled off to form a pressure-sensitive adhesive layer. . Next, after the solar power generation reflector is bonded to this pressure-sensitive adhesive layer, for example, it is aged in an atmosphere of a temperature of 23 ° C. and a humidity of 65% for about 5 to 20 days to sufficiently react the crosslinking agent.

  The raw materials for the acrylic pressure-sensitive adhesive as described above can be easily obtained as commercial products. For example, various acrylic monomers (manufactured by Nippon Shokubai Co., Ltd., manufactured by Toagosei Co., Ltd.), polymerization initiators 2 2,2'-azobisisobutyronitrile, etc. (manufactured by Otsuka Kagaku Co., Ltd., Nihon Finechem Co., Ltd.), hexamethylene diisocyanate as a cross-linking agent, and trimethylolpropane adducts thereof, tolylene diisocyanate, and trimethylolpropane thereof Examples thereof include adduct bodies (Mitsui Chemicals Polyurethane Co., Ltd., Sumika Bayer Urethane Co., Ltd.).

(Holding member)
In the solar power generation reflector of the present invention, it is preferable to use a metal support as a member for holding the solar power generation reflector. For example, a steel plate, a copper plate, an aluminum plate, an aluminum plated steel plate, an aluminum alloy plated steel plate, copper A metal material having high thermal conductivity such as a plated steel plate, a tin-plated steel plate, a chrome-plated steel plate, or a stainless steel plate 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.

[Production of reflector for solar power generation]
(Preparation of reflector for solar thermal power generation (PA-1))
Polyethylene terephthalate resin was melt-extruded with a T-die extruder at 280 ° C. as a base film for the silver reflective layer to produce an unstretched film, and then the film was stretched at a stretching temperature of 120 ° C. in the longitudinal direction by a factor of 3.0. After stretching, the film was stretched 3.5 times in the width direction to produce a biaxially stretched polyester film having a thickness of 30 μm. On one side of the polyethylene terephthalate film, a polyester resin (Polyester SP-181, manufactured by Nippon Synthetic Chemical Co., Ltd.), a melamine resin (Super Becamine J-820, manufactured by DIC), a TDI-based isocyanate (2,4-tolylene diisocyanate) ), A coating liquid prepared by mixing HDMI isocyanate (1,6-hexamethylene diisocyanate) in toluene at a solid content ratio of 20: 1: 1: 2 and a solid content concentration of 10% by mass, using a gravure coating method. To form an easy-adhesion layer having a thickness of 1.0 μm. Further, a silver reflective layer having a thickness of 80 nm is formed as a silver reflective layer on the easy adhesion layer by a vacuum deposition method, and then a polyester resin (Polyester SP-181, Japan) is formed on the silver reflective layer as a silver protective layer. Synthetic Chemical Co., Ltd.) and TDI-based isocyanate at a resin solid content ratio of 10: 2 and a coating solution mixed in toluene so that the solid content concentration is 20% by mass is coated by a gravure coating method to obtain a thickness of 3 A reflective film having a silver protective layer of 0.0 μm and having a silver reflective layer on one side was prepared.

  Next, 100 parts of methacrylic resin (glass transition temperature 105 ° C.) as a hard transparent resin substrate, 1.4 parts of UV absorber (Tinuvin 234, manufactured by BASF) as a compounding agent, antioxidant (ADK STAB AO-50, 0.1 part of ADEKA) and 0.3 part of light stabilizer (LA-67, ADEKA) were mixed using a Henschel mixer. This mixture was melt-kneaded at 240 ° C. with a twin screw extruder into pellets of a resin composition, then melt extruded at 240 ° C. with a T-die extruder, thickness 0.3 mm, width 1 m, length A 1 m plate substrate was produced.

  Next, an adhesive layer made of a polyurethane resin (Seika Bond U-586, curing agent UD-) is formed by sandwiching the silver reflective layer between the reflective film having the silver reflective layer having a width of 1 m and a length of 1 m and the hard transparent resin substrate. C, manufactured by Dainichi Seika Co., Ltd., having a thickness of 5 μm), and the laminated body is supplied to the nip of the pressure roller and bonded together, whereby the reflector for solar power generation of the present invention (PA- 1) was produced.

(Preparation of solar power generation reflector (PA-2))
Reflector for solar power generation (PA-1) except that a plate-like substrate made of methacrylic resin whose thickness was changed to 0.5 mm was used as the hard transparent resin substrate in the production of the solar power generation reflector (PA-1). The reflector for solar power generation (PA-2) of the present invention was prepared in the same manner as in -1).

(Preparation of solar power generation reflector (PA-3))
In the production of the reflector for solar power generation (PA-1), the reflector for solar power generation (PA-1) was used except that a plate-like substrate made of methacrylic resin whose thickness was changed to 5 mm was used as the hard transparent resin substrate. The solar power generation reflector (PA-3) of the present invention was produced in the same manner as in the production of

(Production of reflector for solar thermal power generation (PA-4))
In the production of a solar power generation reflector (PA-1), a polycarbonate resin (glass transition temperature 160 ° C.) pellet is used as a hard transparent resin substrate, and an ultraviolet absorber (Tinuvin 234, manufactured by BASF) as a compounding agent 1 4 parts, 0.1 part of an antioxidant (ADK STAB AO-50, manufactured by ADEKA) and 0.3 part of a light stabilizer (LA-67, manufactured by ADEKA) were added in the same manner, and the melting temperature was 270. The solar power generation reflector (PA-4) of the present invention was produced in the same manner as the production of the solar power generation reflector (PA-1) except that the temperature was set to ° C and the thickness was 0.3 mm.

(Preparation of reflector for solar thermal power generation (PA-5))
In the production of the solar power generation reflector (PA-4), the solar power generation reflector (PA) was used except that a plate substrate made of polycarbonate resin having a thickness of only 0.5 mm was used as the hard transparent resin substrate. The solar power generation reflector (PA-5) of the present invention was prepared in the same manner as in -4).

(Preparation of reflector for solar thermal power generation (PA-6))
In the production of the solar power generation reflector (PA-4), the solar power generation reflector (PA-4) was used except that a plate-like substrate made of polycarbonate resin having a thickness of only 5 mm was used as the hard transparent resin substrate. The reflector for solar power generation (PA-6) of the present invention was produced in the same manner as in the production of

(Preparation of reflector for solar thermal power generation (PA-7))
In the production of a solar power generation reflector (PA-4), a solar power generation reflector (PA-4) was used except that a plate-like substrate made of polycarbonate resin having a thickness of only 10 mm was used as the hard transparent resin substrate. The reflector for solar power generation (PA-7) of the present invention was produced in the same manner as in the production of

(Preparation of reflector for solar thermal power generation (PA-8))
In the production of the solar power generation reflector (PA-4), the solar power generation reflector (PA-4) was used except that a plate-like substrate made of a polycarbonate resin whose thickness was changed to 20 mm was used as the hard transparent resin substrate. The reflector for solar power generation (PA-8) of the present invention was produced in the same manner as in the production of).

(Preparation of reflector for solar thermal power generation (PA-9))
In the production of the solar power generation reflector (PA-1), as the hard transparent resin substrate, norbornene resin (ZEONOR1420, manufactured by Nippon Zeon Co., Ltd., glass transition temperature 135 ° C) is used, the melting temperature is 240 ° C, The solar power generation reflector (PA-9) of the present invention was prepared in the same manner as the solar power generation reflector (PA-1) except that the thickness was 0.3 mm.

(Preparation of reflector for solar thermal power generation (PA-10))
In the production of the solar power generation reflector (PA-9), a solar power generation reflector (except for using a plate substrate made of norbornene-based resin whose thickness is changed to 0.5 mm as the hard transparent resin substrate) The reflector for solar power generation (PA-10) of the present invention was prepared in the same manner as in the preparation of PA-9).

(Preparation of solar power generation reflector (PA-11))
In the production of the solar power generation reflector (PA-9), the solar power generation reflector (PA-) was used except that a plate substrate made of norbornene-based resin whose thickness was changed to 5 mm was used as the hard transparent resin substrate. The reflector for solar power generation (PA-11) of the present invention was produced in the same manner as in 9).

(Preparation of reflector for solar thermal power generation (PA-12))
In the production of a solar power generation reflector (PA-6), the same applies except that an amount adjusted to 0.5 g / m ² after applying butanediol bisthioglycolate as a corrosion inhibitor to the silver protective layer was added. Thus, the reflector for solar power generation (PA-12) of the present invention was produced.

(Preparation of reflector for solar thermal power generation (PA-13))
In the production of the reflector for solar power generation (PA-6), the solar power generation according to the present invention was similarly performed except that a silicon oxide barrier layer having a thickness of 100 nm was formed on the silver protective layer by the following vacuum deposition process. A reflective plate (PA-13) was prepared.

(Barrier layer by vacuum evaporation)
After evacuating until the ultimate vacuum of the chamber reaches 3.0 × 10 ⁻⁵ torr (4.0 × 10 ⁻³ Pa) using a vacuum deposition apparatus, oxygen gas is placed in the vicinity of the coating drum and the pressure in the chamber Is maintained at 3.0 × 10 ⁻⁴ torr (4.0 × 10 ⁻² Pa), and silicon monoxide is evaporated by heating with a pierce-type electron gun at a power of about 10 kW. A silicon oxide barrier layer having a thickness of 100 nm was formed on a polyester film running on a drum at a speed of 120 m / min.

(Preparation of reflector for solar thermal power generation (PA-14))
In the production of a solar power generation reflector (PA-12), the following scratch prevention is provided on the uppermost surface of the substrate made of polycarbonate resin laminated as a hard transparent resin substrate (the side opposite to the surface bonded with the film having the silver reflecting layer). A solar power generation reflector (PA-14) of the present invention was produced in the same manner except that the layer (hard coat layer) was applied.

(Scratch prevention layer)
A coating solution for a scratch-preventing layer having the following composition was prepared as a coating solution, applied to the top surface of the polycarbonate resin substrate using a micro gravure coater so that the film thickness after curing was 5 μm, and the solvent was evaporated. After drying, a hard coat layer was prepared by curing with 0.2 J / cm ² ultraviolet irradiation using a high-pressure mercury lamp.

<Scratch prevention layer coating solution>
Dipentaerythritol hexaacrylate 70 parts by weight Trimethylolpropane triacrylate 30 parts by weight Photoinitiator (Irgacure 184, manufactured by BASF) 4 parts by weight Ethyl acetate 150 parts by weight Propylene glycol monomethyl ether 150 parts by weight Silicone compound (BYK-307, (By Big Chemie Japan) 0.4 parts by mass UV absorber (Tinubin 400, manufactured by BASF) 5 parts by mass (production of reflector for solar thermal power generation (PA-15))
In the production of the reflector for solar power generation (PA-5), the present invention was carried out in the same manner as the production of the reflector for solar power generation (PA-5), except that the silver protective layer was not formed on the silver reflective layer. A solar power generation reflector (PA-15) was prepared.

(Production of reflector for solar thermal power generation (PA-16))
In the production of the reflector for solar power generation (PA-6), the present invention was carried out in the same manner as the production of the reflector for solar power generation (PA-6), except that the silver protective layer was not formed on the silver reflective layer. A solar power generation reflector (PA-16) was prepared.

(Preparation of reflector for solar thermal power generation (PA-17))
Reflector for solar thermal power generation (PA-5) except that the adhesive layer was an adhesive layer made of polyester resin (TM-550, manufactured by Toyo Morton, thickness 5 μm) in the production of the solar power reflective plate (PA-5). In the same manner as in 5), a reflective film for solar power generation (PA-17) of the present invention was prepared.

(Preparation of reflective film for solar thermal power generation (PA-18))
Reflector for solar power generation (PA-5) except that the adhesive layer was made of an acrylic resin adhesive layer (Y-620 Cemedine Co., thickness 5 μm) in the production of the solar power generation reflector (PA-5). The solar power generation reflective film (PA-18) was prepared in the same manner as in (1).

  In addition, all the average transmittance | permeability of wavelength 380nm -700nm of the hard transparent resin substrate used above was 85% or more.

(Production of comparative solar power generation reflector (HPA-1))
In the same manner as in Example 1 of JP-A-2005-59382, a PET (polyethylene terephthalate) sheet having a thickness of 1.0 mm and a sheet obtained by vapor-depositing aluminum on a metallized sheet having a thickness of 0.05 mm are bonded by thermocompression bonding. It laminated | stacked and the reflecting plate for comparative solar thermal power generation (HPA-1) was produced.

(Preparation of comparative solar power generation reflective film (HPA-2))
In the same manner as in FIG. 1 of JP-T-2009-520174, a pressure-sensitive adhesive layer of 0.025 mm from the lower layer, a silver layer, a polyester film layer of 0.025 mm, a polyurethane-based adhesive layer, 0.075 mm A comparative solar power generation reflective film (HPA-2) laminated with a UV shielding acrylic film layer configuration was prepared.

(Preparation of comparative solar power generation reflective film (HPA-3))
As a comparison of the solar power generation reflector (PA-1), in the production of the solar power generation reflector (PA-1), instead of a hard transparent resin substrate, a 0.2 mm thick soft acrylic resin film was produced. A comparative solar power generation reflective film (HPA-3) was prepared in the same manner as the solar power generation reflector (PA-1) except that it was used.

(Preparation of comparative solar power generation reflective film (HPA-4))
As a comparison of the solar power generation reflector (PA-1), in the production of the solar power generation reflector (PA-4), instead of a hard transparent resin substrate, a 0.2 mm thick soft polycarbonate resin film was manufactured. A comparative solar power generation reflective film (HPA-4) was prepared in the same manner as the solar power generation reflector (PA-4) except that it was used.

(Production of comparative solar power generation reflective film (HPA-5))
As a comparison with the solar power generation reflector (PA-1), a soft norbornene resin film having a thickness of 0.2 mm was produced instead of the hard transparent resin substrate in the production of the solar power generation reflector (PA-9). A comparative solar power generation reflective film (HPA-5) was prepared in the same manner as the solar power generation reflector (PA-9) except that it was used.

[Preparation of solar power generation reflector]
(Production of reflectors 1-18 and H1-H5 for solar thermal power generation)
This pressure-sensitive adhesive layer sheet was coated with an acrylic pressure-sensitive adhesive (BPS-5296, hardener BXX4773 manufactured by Toyo Ink Co., Ltd.) so that the thickness after drying was 25 μm, and then dried at 100 ° C. for 2 minutes. For each of the produced solar power reflectors (PA-1) to (PA-18) and comparative solar power reflectors or films (HPA-1) to (HPA-5). The adhesive layer was formed by bonding to the surface of the plate on the polyethylene terephthalate film side (the side opposite to the silver reflective layer). This is bonded to the holding member of an aluminum plate having a thickness of 0.1 mm, a width of 1 m, and a length of 1 m and an adhesive layer of the produced solar power generation reflector or film. 18. Comparative solar power generation reflectors H1 to H5 were produced.

[Evaluation of reflector for solar thermal power generation]
About the produced solar power generation reflector, the comparative solar power generation reflection film, and the solar power generation reflector, the bending stiffness, initial regular reflectance, weather resistance, light resistance, and durability test were performed by the following methods. The reflection surface distortion, salt water resistance, and pencil hardness were evaluated.

(Bending rigidity)
For the solar power generation reflector before being bonded to the aluminum plate, and the comparative solar power generation reflective film, measure according to the bending rigidity test of the concrete formwork plywood in the “Japanese Agricultural Standard for Plywood” and the Young's modulus The value of bending stiffness was calculated from the product of the second moment of section.

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

(Weatherability)
The regular reflectance after standing for 1500 hours under conditions of 85 ° C. and 85% RH as the forced deterioration condition of the weather resistance is measured by the same method as the initial regular reflectance measurement, and the regular reflectance before the forced deterioration and the forced deterioration are measured. From the later regular reflectance, the decrease rate of regular reflectance due to forced deterioration was calculated, and the weather resistance was 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: Decrease rate of regular reflectance is 20% or more (light resistance)
After performing UV irradiation for 300 hours under conditions of 60 ° C. and 60% RH using an ISUPAKI Electric Eye Super UV tester, the regular reflectance was measured by the above method, and the decrease rate of regular reflectance before and after ultraviolet irradiation was measured. The light resistance 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: Regular reflectance decrease rate is 20% or more (reflection surface distortion after endurance test)
Using the samples after the weather resistance test and after the light resistance test, the distortion of the fluorescent lamp image reflected at an angle of about 60 degrees was visually observed, and the distortion of the reflective surface was evaluated according to the following criteria. .

5: No distortion was observed in the samples after both tests 4: Slight distortion was observed in either one of the samples after both tests 3: All of the samples after both tests were slightly 2: Clear distortion was observed in either one of the samples after both tests 1: Clear distortion was observed in the samples after both tests (salt water resistance)
Spraying salt water (pH; 5.6 to 7.0) at a temperature of 25 ° C. for 2 hours and letting it stand at 60 ° C. for 24 hours was one cycle, and 10 cycles were performed to evaluate salt water resistance 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: Decrease rate of regular reflectance is 20% or more (pencil hardness)
Based on JIS-K5400, the pencil hardness of each sample at 45 ° inclination and 1 kg load was measured.

  The above evaluation results are shown in Table 1 together with the main structure of the sample. The bending rigidity in the table represents the measured value of the solar heat reflector used in the solar power generation reflector. Moreover, (circle) of a silver protective layer shows that the silver protective layer was provided, and-shows that the silver protective layer or the contact bonding layer is not provided.

  As is clear from Table 1, it can be seen that the various characteristics of the solar power generation reflector using the solar power generation reflector of the present invention are superior to the comparative example. That is, in the comparative example, when it is tested for a long time in a harsh environment, the weather resistance, light resistance and salt water resistance are greatly reduced, whereas the present invention is good and has excellent durability. I found out. Furthermore, it has been found that when a layer or additive having an effect of improving weather resistance or light resistance is contained, extremely excellent durability is exhibited. That is, in the present invention, it is light and safe, can be installed at a low manufacturing cost, has excellent durability, and has a good regular reflectance with respect to sunlight. It was found that a solar power generation reflector using a solar power generation reflector can be provided.

DESCRIPTION OF SYMBOLS 10 Hard transparent resin substrate 20 Adhesion layer 30 Silver protective layer 40 Silver reflection layer 50 Film base material 60 Adhesive layer 70 Holding member 80 Sunlight

Claims (7)

A reflective plate for solar power generation in which a rigid transparent resin substrate having a bending stiffness of 400 N · cm ² or more and a reflective film having a silver reflective layer provided on a film base on one side are laminated, the reflective film A solar power generation reflecting plate, characterized in that is a solar power generation reflecting plate laminated with a hard transparent resin substrate via an adhesive layer on the silver reflection layer surface side.   The thickness of the said hard transparent resin substrate is 0.5 mm or more and 20 mm or less, The reflector for solar power generation of Claim 1 characterized by the above-mentioned.   The solar power generation reflector according to claim 1, wherein the hard transparent resin substrate is made of a polycarbonate resin.   The said adhesive layer contains a polyurethane-type resin, The reflecting plate for solar power generation of any one of Claims 1-3 characterized by the above-mentioned.   It has a silver protective layer on the surface of the silver reflective layer of the reflective film which has the silver reflective layer provided on the said film base material on one side, The solar heat of any one of Claims 1-4 characterized by the above-mentioned. Reflector for power generation.   A reflector for solar power generation, wherein the reflector for solar power generation according to any one of claims 1 to 5 is used.   It is a manufacturing method which manufactures the reflecting plate for solar power generation as described in any one of Claims 1-5, Comprising: The said silver reflecting layer is formed by silver vapor deposition, The manufacturing method of the reflecting plate for solar power generation characterized by the above-mentioned. .

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