WO2011096284A1

WO2011096284A1 - Film mirror for solar thermal power generation, method for producing film mirror for solar thermal power generation, and reflection device for solar thermal power generation

Info

Publication number: WO2011096284A1
Application number: PCT/JP2011/051082
Authority: WO
Inventors: 望月　誠
Original assignee: コニカミノルタオプト株式会社
Priority date: 2010-02-02
Filing date: 2011-01-21
Publication date: 2011-08-11
Also published as: JPWO2011096284A1

Abstract

Disclosed is a film mirror for solar thermal power generation, which has good specular reflectance of sunlight and is prevented from decrease in the specular reflectance due to deterioration of an adhesive layer that serves as a reflective layer. The film mirror for solar thermal power generation is lightweight, while having flexibility, excellent light resistance and excellent weather resistance. Also disclosed are: a method for producing the film mirror for solar thermal power generation; and a reflection device for solar thermal power generation using the film mirror for solar thermal power generation. The film mirror for solar thermal power generation is characterized by comprising one or more UV absorbing layers that contain an inorganic UV absorbent having a refractive index of 2.4 or less and a silver reflective layer that is configured of silver. The film mirror for solar thermal power generation is also characterized by being provided with an adhesive layer, which is provided for the purpose of being bonded to a supporting body, on a side of the silver reflective layer counter to the light incident side thereof.

Description

Film mirror for solar power generation, method for manufacturing film mirror for solar power generation, and reflector for solar power generation

The present invention relates to a novel film mirror for solar power generation, a method for producing the same, and a reflector for solar power generation using the film mirror.

In recent years, as alternatives to fossil fuel energy such as oil and natural gas, natural energy such as coal energy, biomass energy, nuclear energy, wind energy and solar energy has been studied. The most stable and abundant natural energy is considered to be solar energy. However, although solar energy is a very powerful alternative energy, from the viewpoint of utilizing it, (1) the energy density of solar energy is low, (2) it is difficult to store and transfer solar energy, etc. Is considered to be a problem.

In response to the above-mentioned problem of solar energy, a method of solving the problem of low energy density of solar energy by collecting solar energy with a huge reflector has been proposed. Since the reflecting device is exposed to sunlight, ultraviolet rays, heat, wind and rain, sandstorms, etc., a glass mirror has been conventionally used. Glass mirrors are highly durable to the environment, but they are damaged during transportation or heavy, so it is necessary to increase the strength of the mount on which the mirrors are installed, resulting in increased plant construction costs. It was.

In order to solve the above problem, a method of replacing a glass mirror with a resin reflection sheet has been disclosed (for example, see Patent Document 1). However, in the proposed method, the resin used is weak against the external environment, and when a metal such as silver is used for the reflective layer, oxygen, water vapor, hydrogen sulfide, etc. are transmitted through the resin layer, Due to the problem of corroding silver, it was difficult to apply a resin mirror.

On the other hand, for the purpose of collecting sunlight, a benztriazole-based ultraviolet absorber (hereinafter referred to as UV absorber) is applied to the resin layer located on the incident light side of the silver reflective layer from the viewpoint of obtaining a high reflectance. (Referred to, for example, Patent Document 2), by adding a large amount of (also referred to as)) to suppress a decrease in light transmittance of the resin layer due to discoloration caused by light degradation due to UV light of the resin. Japanese Patent Laid-Open No. 61-154942 discloses that a layer containing a silver corrosion inhibitor is laminated on the upper layer of the silver reflection layer to suppress a decrease in reflectance due to silver corrosion. A method of suppressing a decrease in light transmittance of a resin layer by providing a benztriazole-based UV absorber layer as an upper layer is disclosed.

However, in the method described in Patent Document 2 and the like, the weather resistance is never sufficient, and the adhesive layer provided for attaching the film mirror to the support is deteriorated with the irradiation of sunlight. It was found that peeling or distortion of the adhesive layer occurred. This peeling or distortion of the adhesive layer is a problem that leads to a decrease in the regular reflectance of the film mirror and a decrease in power generation efficiency, and an immediate improvement has been demanded.

JP 2005-59382 A US Patent Application Publication No. 7,507,776B2 Specification

The present invention has been made in view of the above problems, and its purpose is to prevent a decrease in regular reflectance due to deterioration of the adhesive layer that is a reflective layer, and to be lightweight and flexible, and to have light resistance and weather resistance. An object of the present invention is to provide a film mirror for solar power generation that is excellent and has a good regular reflectance with respect to sunlight, a manufacturing method thereof, and a reflector for solar power generation using the same.

As a result of intensive studies on the above problems, the present inventors have determined that the deterioration of the adhesive layer constituting the film mirror for solar power generation is caused by the low molecular weight component of the resin contained in the adhesive layer, the residual polymerization initiator, or the residual monomer ultraviolet rays. It was found that the degradation was due. Furthermore, it has been found that the ultraviolet light for decomposing each of the above components is, in particular, light in the UV-B region (290-320 nm). Such a problem becomes particularly apparent when silver is used for the reflective layer. Although silver has an excellent reflectance in visible light compared to metals such as aluminum, it has a property that it cannot reflect light with a wavelength of 320 nm or less and transmits light in the UV-B region. Therefore, in the past, when considering deterioration due to ultraviolet rays, it was only necessary to consider the deterioration of the light incident side layer of the reflective layer. However, when a silver reflective layer is used, this is not sufficient, and the light passes through the silver reflective layer. It has been found that it is also necessary to suppress deterioration of the layer on the opposite side of the reflective layer by the light in the UV-B region. As a result of further studies, it has been found that an organic UV absorber alone is not sufficient to cut light in the UV-B region. In addition, when the organic UV absorber is made to absorb light in the UV-B region, the organic UV absorber itself deteriorates, so that the UV absorption function gradually decreases, and the above-mentioned adhesive layer is decomposed. As a result, it has become clear that not only the problem of causing regularity of the regular reflectivity to occur, but also the deterioration of the reflectivity due to coloring due to alteration of the organic UV absorber itself or deformation of the layer to which the UV absorber is added, etc. . Therefore, as a result of further studies, when a layer containing an inorganic UV absorber is provided, it is possible to provide sufficient absorption for ultraviolet rays in the UV-B region, It has been found that the deterioration of the UV absorber itself due to UV rays in the UV-B region can be suppressed, the deterioration of the adhesive layer can be suppressed, and as a result, the decrease in regular reflectance can be suppressed. It is up to the invention.

That is, the above object of the present invention is achieved by the following configuration.

1. It has one or more UV absorbing layers containing an inorganic UV absorber having a refractive index of 2.4 or less, and a silver reflecting layer composed of silver, and an adhesive layer is provided on the side opposite to the incident light with respect to the silver reflecting layer. A film mirror for solar power generation, comprising:

2. 2. The film mirror for solar power generation as described in 1 above, wherein the inorganic UV absorber is fine particles having an average particle diameter of 10 nm or more and 100 nm or less.

3. 2. The film mirror for solar power generation according to 1 above, wherein the inorganic UV absorber is fine particles having a surface-coated average particle diameter of 10 nm or more and 100 nm or less.

4. The film mirror for solar power generation according to any one of 1 to 3, wherein the UV absorption layer further contains an organic UV absorber.

5. Furthermore, it has an organic UV absorber layer containing an organic UV absorber, The film mirror for solar thermal power generation of any one of said 1 to 4 characterized by the above-mentioned.

6. The organic UV absorber layer is disposed on the incident light side with respect to the silver reflective layer, and the inorganic UV absorber layer is disposed on the side opposite to the incident light with respect to the silver reflective layer. A film mirror for solar power generation as described in 1.

7. The inorganic UV absorber layer is disposed on the incident light side with respect to the silver reflective layer, and the organic UV absorber layer is disposed on the anti-incident light side with respect to the silver reflective layer. 5. A film mirror for solar power generation according to 5.

8. The method for manufacturing a solar power generation film mirror according to any one of 1 to 7 above, wherein the silver reflective layer is formed by vapor deposition of silver. A manufacturing method of a film mirror.

9. A solar power generation reflecting device, wherein the solar power generation film mirror according to any one of 1 to 7 is bonded to a metal support through an adhesive layer.

According to the present invention, even when used as a film mirror for solar power generation in a very harsh environment, the adhesive layer does not deteriorate, and solar heat capable of maintaining a high regular reflectance over a long period of time. Film mirror for power generation. This is considered to be an effect obtained by providing a layer containing an inorganic UV absorber having a refractive index of 2.4 or less on the incident side of the adhesive layer.

It is a schematic sectional drawing which shows an example of a structure of the film mirror for solar power generation of this invention. It is a schematic sectional drawing which shows another example of a structure of the film mirror for solar power generation of this invention. It is a schematic sectional drawing which shows another example of a structure of the film mirror for solar power generation of this invention. It is a schematic sectional drawing which shows another example of a structure of the film mirror for solar power generation of this invention. It is a schematic sectional drawing which shows another example of a structure of the film mirror for solar power generation of this invention.

Hereinafter, modes for carrying out the present invention will be described in detail, but the present invention is not limited to these.

As a result of intensive studies, the present inventors have one or more UV absorbing layers containing an inorganic UV absorber having a refractive index of 2.4 or less, and a silver reflecting layer composed of silver, and the silver reflecting layer Due to the peeling or distortion of the adhesive layer by the film mirror for solar power generation, which has an adhesive layer for forming a solar power generation reflecting device by adhering to a metal support etc. on the side opposite to the incident light side It has been found that the problem of lowering the regular reflectance of the film mirror is solved. This is because the inorganic UV absorber having a refractive index of 2.4 or less absorbs the wavelength in the UV-B region without causing irregular reflection, and decomposes the low molecular weight component of the adhesive layer resin, the residual polymerization initiator or the residual monomer. This is thought to be due to the suppression of the above.

Hereinafter, specific configuration examples of the film mirror for solar power generation according to the present invention will be described with reference to the drawings.

FIG. 1 shows an example of a typical configuration of a film mirror for solar power generation according to the present invention.

In the film mirror 1 for solar thermal power generation according to the present invention shown in FIG. 1, the hard coat layer 2, the UV absorbing layer 3 containing the inorganic UV absorber 8, the corrosion prevention layer 4, the silver reflection from the incident light side (upper part of the drawing). Layer 5, resin support layer 6, and adhesive layer 7 are laminated in this order.

Further, FIGS. 2 to 5 show examples of a more preferable configuration of the film mirror for solar power generation according to the present invention.

The film mirror 1 for solar power generation shown in FIG. 2 includes a hard coat layer 2, an inorganic UV absorber 8 and an organic UV absorber 9 containing a UV absorber layer 3 'and a corrosion inhibitor from the incident light side (upper part of the drawing). The layer 4, the silver reflection layer 5, the resin support layer 6, and the adhesive layer 7 are laminated in this order.

In the configuration shown in FIG. 2, by using the inorganic UV absorber 8 and the organic UV absorber 9 together as the UV absorbing layer 3 ′, the transmittance of the organic UV absorber 9 is suppressed while suppressing the deterioration of the adhesive layer 7. It is possible to reduce the content of the low inorganic UV absorber 8, and as a result, the reflectance is improved.

In the film mirror 1 for solar thermal power generation shown in FIG. 3, the hard coat layer 2, the organic UV absorber-containing layer 10 containing the organic UV absorber 9, the corrosion inhibitor layer 4, silver from the incident light side (upper part of the drawing) The reflective layer 5, the inorganic UV absorber-containing layer 11 containing the inorganic UV absorber 8, the resin support layer 6, and the adhesive layer 7 are laminated in this order. In the configuration shown in FIG. 3, the inorganic UV absorber-containing layer 11 is present on the counter-incident light side (lower part of the drawing) with respect to the silver reflective layer 5, so that the reflectance is increased. In addition, the organic UV absorber-containing layer 10 can prevent resin deterioration of the corrosion inhibitor layer 4 located below. Furthermore, since the inorganic UV absorber-containing layer 11 on the anti-incident light side of the silver reflecting layer 5 absorbs light having a wavelength of 320 nm or less that passes through the silver reflecting layer 5, deterioration of the adhesive layer 7 can be suppressed. At this time, the inorganic UV absorber-containing layer 11 can contain a large amount of the inorganic UV absorber 8 as the transparency decreases, and the light resistance of the adhesive layer 7 is further improved.

In the film mirror 1 for solar thermal power generation shown in FIG. 4, from the incident light side, the hard coat layer 2, the inorganic UV absorber-containing layer 11 containing the inorganic UV absorber 8, the corrosion inhibitor layer 4, the silver reflecting layer 5, and the organic The organic UV absorber-containing layer 10 containing the UV absorber 9, the resin support layer 6, and the adhesive layer 7 are laminated in this order. In the configuration shown in FIG. 4, since there is a UV absorption contribution by the organic UV absorber-containing layer 10, the inorganic UV absorber 8 having a lower transmittance than the organic UV absorber 9 while suppressing deterioration of the adhesive layer 7 is contained. The amount can be reduced, and as a result, the reflectance is improved.

In the film mirror 1 for solar thermal power generation shown in FIG. 5, from the incident light side, the hard coat layer 2, the inorganic UV absorber-containing layer 11 containing the inorganic UV absorber 8, the corrosion inhibitor layer 4, the silver reflecting layer 5, and the resin It is the structure laminated | stacked in order of the support body layer 6, the organic UV absorber content layer 10 containing the organic UV absorber 9, and the adhesion layer 7. FIG. Even in the configuration shown in FIG. 5, since there is a UV absorption contribution by the organic UV absorber-containing layer 10, the inorganic UV absorber 8 having a transmittance lower than that of the organic UV absorber 9 while suppressing deterioration of the adhesive layer 7 is contained. The amount can be reduced, and as a result, the reflectance is improved.

Hereinafter, details of each component of the film mirror for solar power generation of the present invention will be described.

[Hard coat layer]
In the film mirror for solar power generation of the present invention, a hard coat layer can be provided as the outermost layer. The hard coat layer according to the present invention is provided for preventing scratches.

The hard coat layer according to the present invention can be composed of, for example, an acrylic resin, a urethane resin, a melamine resin, an epoxy resin, an organic silicate compound, a silicone resin, or the like as a binder. In particular, silicone resins and acrylic resins are preferable in terms of hardness and durability. Furthermore, it is preferable to apply an active energy ray-curable acrylic resin or a thermosetting acrylic resin in terms of curability, 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, a modifier, etc. as needed.

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

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

Examples of commercially available polyfunctional acrylic cured paints include “Diabeam Series” manufactured by Mitsubishi Rayon Co., Ltd., “Denacol Series” manufactured by Nagase Sangyo Co., Ltd., and “NK Ester Series” manufactured by Shin Nakamura Co., Ltd. , "Unidic Series" manufactured by DIC Corporation, "Aronix Series" manufactured by Toagosei Co., Ltd., "Blemmer Series" manufactured by Nippon Oil & Fats Co., Ltd., "KAYARAD Series" manufactured by Nippon Kayaku Co., Ltd. Examples include “Light Ester Series” and “Light Acrylate Series” manufactured by the company.

In the hard coat layer according to the present invention, various additives can be further blended as necessary within the range where the effects of the present invention are not impaired. For example, stabilizers such as antioxidants, light stabilizers, UV absorbers, surfactants, leveling agents, antistatic agents, and the like can be used.

The leveling agent is particularly effective in reducing surface irregularities when a hard coat 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.

[UV absorption layer]
The UV absorbing layer according to the present invention has a constitution in which a UV absorber is dispersed in the form of particles in an inorganic oxide or resin.

The film mirror for solar power generation according to the present invention is characterized by having a UV absorbing layer containing an inorganic UV absorber having a refractive index of 2.4 or less. The UV absorbing layer according to the present invention may be a layer containing both an inorganic UV absorber and an organic UV absorber, or an inorganic UV agent-containing layer containing an inorganic UV absorber and an organic UV absorber. The organic UV agent containing layer to contain may be the structure which exists separately each independently.

In addition, the UV absorbing layer containing an inorganic UV absorber is preferably 3.0 μm or more and 150 μm or less from the viewpoint of UV cut ability and film rollability.

<Inorganic oxide>
One form of the UV absorbing layer according to the present invention is a configuration in which UV absorber particles are dispersed in an inorganic oxide. As the inorganic oxide, it is preferable to use an inorganic oxide formed by local heating from a sol using an organometallic compound as a raw material. 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, etc., preferably silicon oxide.

In the present invention, as a method for 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>
The sol-gel method referred to in the present invention refers to obtaining a metal oxide or hydroxide sol from an organometallic compound solution such as a metal alkoxide or an inorganic compound solution, further gelling this, and heating this gel to produce ceramic or This is a method for producing glass. A method for producing a silicon dioxide thin film comprising the steps of hydrolyzing silicon alkoxide in an alcohol solvent and subjecting it to condensation polymerization to obtain a sol, forming the sol into a thin film, and then heating and firing the sol thin film. It has already been known and put into practical use as a method for producing a silicon dioxide thin film by a gel method.

In general manufacturing method of silicon dioxide thin film by sol-gel method, tetramethoxy silicon, tetraethoxy silicon, tetra-n-propoxy silicon, tetraisopropoxy silicon, tetra-n-butoxy silicon, tetraisobutoxy silicon, tetra- Tetraalkoxy silicon such as t-butoxy silicon or a derivative thereof is dissolved in a lower aliphatic alcohol solvent such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, and water is added thereto. By stirring and mixing at room temperature or optionally with heating, at least a part of tetraalkoxysilicon or a derivative thereof is hydrolyzed, and then a condensation polymerization reaction occurs between the hydrolysates, resulting in a condensation polymer. Produces. And it is the method of shape | molding this in the form of a thin film in the state of the low-viscosity sol which is a state in which the progress of the condensation polymerization is not enough.

<Method of applying polysilazane>
The method of applying polysilazane is a method of forming a silicon oxide film by using a solution containing at least one perhydropolysilazane represented by the following formula (1) as a coating solution and curing it by light irradiation.

Formula (1)
-(SiH ₂ NH)-
Thus, by applying a coating liquid in which polysilazane is dispersed in a solvent and curing it by light irradiation, a dense silicon oxide film or the like can be obtained in a short time.

Furthermore, as another preferred embodiment, a solution containing at least one polysilazane represented by the following formula (2) is used.

Formula (2)
-(SiR ₁ R ₂ -NR ₃ ) _n- (SiR ₄ R ₅ -NR ₆ ) _p-
In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom or an optionally substituted alkyl group, aryl group, vinyl group, or (trialkoxy). Silyl) alkyl group, where n and p are integers, and n is determined such that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol.

Particularly preferred are 1) compounds in which R ₁ , R ₃ and R ₆ each represent a hydrogen atom, and R ₂ , R ₄ and R ₅ each represent a methyl group, and 2) R ₁ , R ₃ and R ₆ are A compound in which each represents a hydrogen atom, and R ₂ , R ₄ each represents a methyl group, and R ₅ represents a vinyl group, 3) R ₁ , R ₃ , R ₄ and R ₆ each represent a hydrogen atom, and R ₂ and R ₅ are compounds each representing a methyl group.

A solution containing at least one polysilazane represented by the following formula (3) is also preferable.

Formula (3)
-(SiR ₁ R ₂ -NR ₃ ) _n- (SiR ₄ R ₅ -NR ₆ ) _p- (SiR ₇ R ₈ -NR ₉ ) _q-
In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ , R ₈ and R ₉ are independently of one another a hydrogen atom or an optionally substituted alkyl group, aryl Represents a group, a vinyl group or a (trialkoxysilyl) alkyl group, where n, p and q are integers, and n is such that the polysilazane has a number average molecular weight of 150 to 150,000 g / mol. Determined.

Particularly preferred are R ₁ , R ₃ and R ₆ each representing a hydrogen atom, and R ₂ , R ₄ , R ₅ and R ₈ each representing a methyl group and R ₉ representing a (triethoxysilyl) propyl group. And a compound in which R ₇ represents an alkyl group or a hydrogen atom.

The ratio of polysilazane in the solvent is generally 1 to 80% by mass, preferably 5 to 50% by mass, particularly preferably 10 to 40% by mass as polysilazane. Especially as a solvent, it is an organic system which does not contain water and a reactive group (for example, hydroxyl group or amine group), and is inactive with respect to polysilazane, and preferably an aprotic solvent. 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 dialkyls Ether (diglymes) or a mixture of these solvents.

Additional components of the polysilazane solution are further binders such as those conventionally used in the production 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. Still other components of the polysilazane formulation include, for example, additives that affect the formulation viscosity, substrate wetting, film formability, lubrication or exhaust properties, or inorganic nanoparticles such as SiO ₂ , TiO ₂ , It can be ZnO, ZrO ₂ or Al ₂ O ₃ . By using such a method, it is possible to produce a dense glass layer that has a high barrier action against gas because there are no cracks and holes. The silicon oxide layer, the alkyl group-containing silicon oxide layer, or the polymer layer containing silicon oxide may be formed by applying light having a wavelength of 150 nm to 250 nm after applying a polysilazane solution (liquid containing a silicon oxide precursor). preferable. Suitable radiation sources include an excimer radiator having a maximum emission at about 172 nm, a low pressure mercury vapor lamp having an emission line at about 185 nm, and a medium and high pressure mercury vapor lamp having a wavelength component of 230 nm or less, and a maximum emission at about 222 nm. It is an excimer lamp.

Using a radiation source having a radiation component with a wavelength of 180 nm or less, for example a Xe ₂ ^* excimar radiator having a maximum emission at about 172 nm, the high of these gases in the above wavelength range in the presence of oxygen and / or water vapor Ozone and oxygen radicals and hydroxyl radicals are generated very efficiently by photolysis because of the extinction coefficient, which accelerates the oxidation of the polysilazane layer. However, both mechanisms, namely the cleavage of Si—N bonds and the action of ozone, oxygen radicals and hydroxyl radicals, can only occur after VUV radiation reaches the surface of the polysilazane layer.

In addition, the silicon oxide layer, the alkyl group-containing silicon oxide layer, or the polymer layer containing silicon oxide is formed by applying light having a wavelength of 1 μm to 3 μm after applying a polysilazane solution (liquid containing a silicon oxide precursor). May be. Specifically, it is cured by irradiation with infrared pulsed light. In this case, since the heat rays are reflected by the silver surface as the reflective layer, the film as the substrate can be efficiently cured without damage.

<Binder resin containing UV absorber>
Examples of other forms of the UV absorbing layer according to the present invention include films in which UV absorber particles are dispersed in various conventionally known resins. Examples of the resin film used as the substrate include cellulose ester film, polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate and polyethylene naphthalate. , Polyethylene film, polypropylene film, cellophane, cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene series Film, polycarbonate film, norbornene tree Films, polymethylpentene films, polyether ketone films, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, and acrylic films. Among these, a polycarbonate film, a polyester film, a norbornene resin film, and a cellulose ester film are preferable.

In particular, it is preferable to use an acrylic film. Moreover, even if it is the film manufactured by melt casting film forming, the film manufactured by solution casting film forming may be sufficient.

<Inorganic UV absorber>
The inorganic UV absorber according to the present invention is mainly a metal oxide pigment, and is dispersed in an acrylic resin at a concentration of 20% by mass or more to form a film having a thickness of 6 μm. The UV-B region (290- A compound having a function of reducing the light transmittance in the region of 320 nm) to 10% or less is preferable. The inorganic UV absorber applicable to the present invention is particularly preferably selected from zinc oxide, iron oxide, zirconium oxide, cerium oxide or a mixture thereof.

Further, the inorganic UV absorber according to the present invention has a refractive index of 2.4 or less. An inorganic UV absorber having a refractive index greater than 2.4 is not preferable as a UV absorber for a film mirror for solar power generation because irregular reflection is large and causes a decrease in the transparency and regular reflectance of the UV absorbing layer. Further, the inorganic UV absorber according to the present invention preferably has a refractive index of 1.5 or more and 2.4 or less. Here, the refractive index refers to a numerical value measured at a temperature of 25 ° C. at a wavelength of sodium D line (wavelength 589 nm). In addition, from the viewpoint of improving the transparency of the inorganic UV absorber-containing layer, those having an average basic particle diameter of between 5 nm and 500 nm are preferable, and an average base between 10 nm and 100 nm is particularly preferable. It is a metal oxide particle having a particle size and a maximum particle size distribution of 150 nm or less. This type of coated or uncoated metal oxide pigment is described in more detail in patent application EP-A-0 518 773.

Further, in the present invention, from the viewpoint of suppressing the oxidative degradation effect of the adjacent resin due to the photocatalytic ability of the inorganic oxide, the inorganic UV absorber fine particles having an average particle diameter of 10 nm or more and 100 nm or less coated on the surface of the inorganic UV absorber. It is preferable that Moreover, since surface coating also has the effect of improving the dispersibility of inorganic UV absorber particles, it is still preferable. The surface-coated inorganic UV absorbers herein include amino acids, beeswax, fatty acids, fatty alcohols, anionic surfactants, lecithins, sodium salts, potassium salts, zinc salts, iron salts or aluminum salts of fatty acids, metal alkoxides. Chemical, electronic, mechanochemical or mechanical, with compounds such as (titanium or aluminum), polyethylene, silicone, protein (collagen, elastin), alkanolamine, silicon oxide, metal oxide or sodium hexametaphosphate An inorganic UV absorber that has undergone surface treatment by one or more means of special nature.

Also, the surface coating has an effect of adjusting the refractive index of the inorganic UV absorber particles. For example, the refractive index of the surface-coated UV absorber particles themselves can be lowered by coating the surface of the inorganic UV absorber particles having a high refractive index with a material having a low refractive index. The refractive index of the surface-coated UV absorber particles can be controlled mainly by the type and amount of the material to be surface-coated.

The amount of inorganic UV absorber used alone is 1 to 30% by mass, preferably 5 to 25% by mass, more preferably 15 to 20% by mass, based on the total mass of the UV absorbing layer. When the amount is more than 30% by mass, the adhesion is deteriorated, and when the amount is less than 1% by mass, the weather resistance improving effect is small.

When the inorganic UV absorber is used in combination with the organic UV absorber described later, the amount of the inorganic UV absorber used is 3 to 20% by mass, preferably 5 to 10% by mass, based on the total mass of the UV absorbing layer. The organic UV absorber is used in an amount of 0.1 to 10% by mass, preferably 0.5 to 5% by mass. When an inorganic UV absorber and an organic UV absorber are used in combination within the above-mentioned range of use, the transparency of the UV absorbing layer is high and the weather resistance is also good.

<Organic UV absorber>
Examples of the organic UV absorber applicable to the present invention include benzophenone-based, benzotriazole-based, phenyl salicylate-based, triazine-based and the like.

Examples of benzophenone ultraviolet absorbers 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' -Tetrahydroxy-benzophenone and the like.

Examples of benzotriazole ultraviolet absorbers include 2- (2′-hydroxy-5-methylphenyl) benzotriazole and 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 the hindered amine ultraviolet absorber 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 Triazine, 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.

Organic UV absorbers include compounds having a function of converting the energy held by ultraviolet rays into vibrational energy in the molecule and releasing the vibrational energy as heat energy or the like in addition to the above. Furthermore, a substance that exhibits an effect when used in combination with an antioxidant or a colorant, or a light stabilizer called a quencher that acts as a light energy converter can be used in combination. However, when the above organic UV absorber is used, it is necessary to select a material in which the light absorption wavelength of the organic UV absorber does not overlap with the effective wavelength of the photopolymerization initiator.

When using an ordinary organic UV absorber, it is effective to use a photopolymerization initiator that generates radicals with visible light.

The amount of the organic UV absorber used is 0.1 to 20% by mass, preferably 1 to 15% by mass, and more preferably 3 to 10% by mass with respect to the total mass of the UV absorbing layer. When the amount is more than 20% by mass, the adhesion is deteriorated.

(Corrosion prevention layer)
Examples of the structure of the corrosion prevention layer according to the present invention include a layer formed only from a corrosion inhibitor or a layer made of a resin containing a corrosion inhibitor, and is a resin layer containing a corrosion inhibitor. Is preferred. More preferably, a resin layer containing 0.01 to 10% by mass of a corrosion inhibitor is used.

Furthermore, the resin used for the corrosion inhibitor layer should preferably have a function also as an adhesive layer, and is particularly limited as long as it has a function of improving the adhesion between the silver reflective layer and the resin base material layer (resin film). There is no. Therefore, the resin used for the corrosion inhibitor layer is an adhesive that adheres the resin base material (resin film) and the silver reflective layer, heat resistance that can withstand heat when the silver reflective layer is formed by a vacuum deposition method, And the smoothness for extracting the high reflective performance which a silver reflective layer originally has is required.

The resin used for the corrosion inhibitor layer according to the present invention is not particularly limited as long as it satisfies the above conditions of adhesion, heat resistance and smoothness, and polyester resin, acrylic resin, melamine resin. Epoxy resin, polyamide resin, vinyl chloride resin, vinyl chloride vinyl acetate copolymer resin, etc. can be used singly or as a mixed resin. From the viewpoint of weather resistance, a mixed resin of polyester resin and melamine resin can be used. It is more preferable to use a thermosetting resin in which a curing agent such as isocyanate is further mixed.

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

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

(Corrosion inhibitor)
Corrosion inhibitors and antioxidants having an adsorptive group for silver are preferably used as the corrosion inhibitor used in the corrosion prevention layer according to the present invention for the purpose of preventing corrosion of the silver reflection layer.

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

In the film mirror for solar thermal power generation of the present invention, the adhesion preventing layer described later contains an antioxidant, and the corrosion preventing layer contains a corrosion inhibiting agent having an adsorptive group for silver as an upper adjacent layer of the silver reflecting layer. It is preferable to provide an embodiment.

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

<Corrosion inhibitor having an adsorptive group for silver>
Examples of the corrosion inhibitor having an adsorptive group for silver applicable to the present invention include amines and derivatives thereof, compounds having a pyrrole ring, compounds having a triazole ring, compounds having a pyrazole ring, and compounds having a thiazole ring. It is desirable that the compound is selected from a compound having an imidazole ring, a compound having an indazole ring, a copper chelate compound, a thiourea, a compound having a mercapto group, 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, monoethanolamine benzoate, dicyclohexylammonium benzoate , Diisopropyl ammonium benzoate, diisopropyl ammonium nai Light, cyclohexylamine carbamate, nitronaphthalene nitrite, cyclohexylamine benzoate, dicyclohexylammonium cyclohexanecarboxylate, cyclohexylamine cyclohexane carboxylate, dicyclohexylammonium acrylate, cyclohexylamine acrylate, or mixtures thereof.

Examples of compounds 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'- Droxy-5'-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy-4-octoxyphenyl) ) Benzotriazole and the like, or a mixture thereof.

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

Examples of the compound having a thiazole ring include thiazole, thiazoline, thiazolone, thiazolidine, thiazolidone, isothiazole, benzothiazole, 2-N, N-diethylthiobenzothiazole, P-dimethylaminobenzallodanine, and 2-mercaptobenzo. Examples include thiazole 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, and 1-benzyl-2. -Methylimidazole, 2-phenyl-4-methylimidazole, 1-cyanoethyl-2-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole, 1-cyanoethyl-2- Undecylimidazole, 2-phenyl-4-methyl-5-hydromethylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, 4-formylimidazole, 2-methyl-4-formylimidazole, 2-phenyl Ru-4-formylimidazole, 4-methyl-5-formylimidazole, 2-ethyl-4-methyl-5-formylimidazole, 2-phenyl-4-methyl-4-formylimidazole, 2-mercaptobenzo Examples thereof include imidazole and the like, or a mixture thereof.

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, if the materials described above are added, for example, mercaptoacetic acid, thiophenol, 1,2-ethanediol, 3-mercapto-1,2,4-triazole, 1-methyl-3 -Mercapto-1,2,4-triazole, 2-mercaptobenzothiazole, 2-mercaptobenzimidazole, glycol dimercaptoacetate, 3-mercaptopropyltrimethoxysilane, etc., or a mixture thereof.

Examples of naphthalene-based compounds include thionalide.

[Silver reflection layer]
As a method for forming the silver reflective layer according to the present invention, either a wet method or a dry method can be applied.

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

On the other hand, the dry method is a general term for a vacuum film-forming method, and specific examples include, for example, a resistance heating vacuum deposition method, an electron beam heating vacuum deposition method, an ion plating method, and an ion beam. Examples include assisted vacuum deposition and sputtering. In particular, in the present invention, a vapor deposition method capable of applying a roll-to-roll method of continuously forming a film is preferably used. That is, in the manufacturing method of the film mirror for solar power generation which manufactures the film mirror for solar power generation of this invention, it is an aspect formed using the process of forming the silver reflection layer which concerns on this invention by silver vapor deposition.

The thickness of the silver reflective layer according to the present invention is preferably 10 to 200 nm, more preferably 30 to 150 nm, from the viewpoint of reflectivity and the like.

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

[Resin substrate]
As the resin base material according to the present invention, various publicly known resin films can be used. For example, cellulose ester film, polyester film, polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyethylene terephthalate, polyethylene naphthalate polyester film, polyethylene film, polypropylene film, cellophane, Cellulose diacetate film, cellulose triacetate film, cellulose acetate propionate film, cellulose acetate butyrate film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, syndiotactic polystyrene film, polycarbonate film, norbornene resin film , Polymethylpentenef Can Lum, polyether ketone film, polyether ketone imide film, a polyamide film, a fluororesin film, a nylon film, polymethyl methacrylate film, and acrylic films.

Of these, polycarbonate films, polyester films, norbornene resin films, and cellulose ester films are preferred. In particular, it is preferable to use a polyester film or a cellulose ester film, and it may be a film manufactured by melt casting or a film manufactured by solution casting.

It is preferable that the thickness of the resin base material is an appropriate thickness depending on the type and purpose of the resin. For example, it is generally in the range of 10 to 300 μm. The thickness is preferably 20 to 200 μm, more preferably 30 to 100 μm.

(Adhesive layer)
The configuration of the pressure-sensitive adhesive layer according to the present invention is not particularly limited, and for example, any of a dry laminating agent, a wet laminating agent, a pressure-sensitive adhesive, a heat seal agent, a hot melt agent, and the like is used.

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

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

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

The other base material to be bonded to the solar power generation film mirror of the present invention may be any material that can impart protection of the silver reflective layer, for example, an acrylic film or sheet, a polycarbonate film or sheet, a polyarylate film or Sheet, polyethylene naphthalate film or sheet, polyethylene terephthalate film or sheet, plastic film or sheet such as fluorine film, or resin film or sheet kneaded with titanium oxide, silica, aluminum powder, copper powder, or the like A resin film or sheet coated with a resin and subjected to surface processing such as metal deposition is used.

The thickness of the laminated film or sheet is not particularly limited but is preferably in the range of 12 to 250 μm.

In addition, these other base materials may be bonded after providing recesses or projections before being bonded to the solar power generation film mirror of the present invention. Alternatively, the bonding and the molding so as to have a concave portion or a convex portion may be performed at the same time.

[Thickness of film mirror for solar power generation]
The total thickness of the film mirror for solar power generation of the present invention is preferably from 75 to 250 μm, more preferably from 90 to 230 μm, particularly preferably from 100 to 220 μm, from the viewpoint of mirror deflection prevention, regular reflectance, handling properties, and the like. It is.

[Reflector for solar thermal power generation]
The film mirror for solar power generation of the present invention can be preferably used for the purpose of collecting sunlight. Although it can be used as a solar light collecting mirror by itself as a film mirror for solar thermal power generation, more preferably, an adhesive layer coated on the resin substrate surface opposite to the side having the silver reflective layer with the resin substrate interposed therebetween The film mirror for solar power generation of the present invention is pasted on another substrate, particularly a metal support, and used as a reflector for solar power generation of the present invention.

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 multiple 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 film mirror for solar power generation of the present invention is particularly preferably used.

<Support>
As the support used in the solar power generation reflecting device of the present invention, a metal plate, a resin plate, or a composite plate of metal and resin can be used. As the metal plate, a metal material having high thermal conductivity such as a steel plate, a copper plate, an aluminum plate, an aluminum-plated steel plate, an aluminum-based alloy-plated steel plate, a copper-plated steel plate, a tin-plated steel plate, a chrome-plated steel plate, or a stainless steel plate can be used. Also, as resin plates, acrylic resin plates, urethane resin plates, polystyrene resin plates, polyimide resin plates, phenolic resin plates, polycarbonate resin plates, alicyclic hydrocarbon resin plates, polypropylene resin plates Polyolefin resin plates, melamine resin resin plates, and ABS resin plates can be used. Moreover, as a composite board of a metal and resin, what laminated | stacked the said metal plate and the resin board, what laminated | stacked the said metal plate and foamable resin, etc. can be used. Here, the foamable resin means a porous resin, and examples thereof include those composed of polystyrene, polyolefin, polyurethane, melamine resin, and polyimide compositions.

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.

《Preparation of solar power reflectors》
[Preparation of Sample 1: Example 1]
A biaxially stretched polyester film (polyethylene terephthalate film, thickness 100 μm) was used as the resin substrate. A silver reflective layer having a thickness of 80 nm is formed as a silver reflective layer on one side of the polyethylene terephthalate film by a vacuum deposition method, and a polyester resin and a toluene diisocyanate resin are solidified on the silver reflective layer. Add a glycol dimercaptoacetate as an anti-corrosion agent in an amount of 0.3 g / m ² in a resin mixed at a 10: 2 fractional ratio (mass ratio), and coat by gravure coating. Then, a corrosion prevention layer having a thickness of 0.1 μm was formed.

Subsequently, an acrylic resin and an iron oxide (made by Nippon Quantum Design Co., Ltd.) having an average particle diameter of 15% by mass with respect to the acrylic resin of 20 nm and a refractive index of 2.4 are manufactured under the condition that the solid content ratio is 10: 2. The coating solution dissolved and dispersed using a methylene chloride solvent was coated by a gravure coating method to form a 30 μm thick UV absorbing layer. Next, Opstar (manufactured by JSR), which is a UV curable hard coat liquid, is applied onto the formed UV absorbing layer using an applicator, and irradiated with UV light having a wavelength of 350 nm for 30 seconds. A 10 μm hard coat layer was formed.

Next, an acrylic resin adhesive (manufactured by Showa Polymer Co., Ltd.) with a thickness of 10 μm as an adhesive layer is coated on the surface opposite to the surface on which the hard coat layer of the polyethylene terephthalate film of the base material is formed. Film mirror 1 was prepared.

Next, a 0.1 mm thick, 4 cm × 5 cm wide aluminum plate (manufactured by Sumitomo Light Metal Co., Ltd.) is attached via the adhesive layer of the solar thermal power generation film mirror 1 produced above, and a solar thermal power generation reflection device Sample 1 was prepared.

[Preparation of Sample 2: Example 2]
In the preparation of Sample 1, the average particle size was 20 nm and the refractive index was replaced with iron oxide particles having an average particle size of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. A film mirror 2 for solar power generation was prepared in the same manner except that cerium oxide of 2.2 was used (manufactured by Big Chemie Japan Co., Ltd.), and a sample 2 that was a reflector for solar power generation was prepared using this. .

[Production of Sample 3: Example 3]
In the preparation of Sample 1, the average particle size was 20 nm and the refractive index was replaced with iron oxide particles having an average particle size of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. Was prepared in the same manner except that 1.9 zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) was used, and a solar power generation reflector 3 was prepared using this film mirror 3 for solar power generation. .

[Preparation of Sample 4: Example 4]
In the preparation of Sample 1, the average particle diameter was 500 nm and the refractive index was replaced with iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. The film mirror 4 for solar power generation was produced in the same manner except that 2.4 iron oxide (manufactured by Nippon Quantum Design Co., Ltd.) was used, and the sample 4 which is a reflector for solar power generation was produced using this. .

[Preparation of Sample 5: Example 5]
In the preparation of Sample 1, the average particle diameter was 500 nm and the refractive index was replaced with iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. The film mirror 5 for solar power generation was produced in the same manner except that cerium oxide of 2.2 (made by Big Chemie Japan Co., Ltd.) was used, and the sample 5 which was a reflector for solar power generation was produced using this. .

[Preparation of Sample 6: Example 6]
In the preparation of Sample 1, the average particle diameter was 500 nm and the refractive index was replaced with iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. The film mirror 6 for solar power generation was produced in the same manner except that zinc oxide of 2.5 (manufactured by Sakai Chemical Industry Co., Ltd.) was used, and the sample 6 which was a reflector for solar power generation was produced using this. .

[Preparation of Sample 7: Example 7]
In the preparation of Sample 1, the surface silica having an average particle diameter of 20 nm is used instead of the iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorbing layer of the film mirror 1 for solar power generation. A film mirror 7 for solar power generation was produced in the same manner except that the coated iron oxide was used, and a sample 7 which was a reflector for solar power generation was produced using this.

The surface-silica-coated iron oxide is prepared by stirring iron oxide (manufactured by Nippon Quantum Design Co., Ltd.) having an average particle size of 18 nm in a tetraethoxysilane (manufactured by Sigma Aldrich) for 30 minutes, followed by centrifugation and decantation. And pure water addition was repeated for washing.

[Preparation of Sample 8: Example 8]
In the preparation of the sample 7, the surface silica-coated cerium oxide having an average particle size of 20 nm was used in place of the surface silica-coated iron oxide having an average particle size of 20 nm used for forming the UV absorbing layer of the film mirror 7 for solar power generation. Except for the above, a film mirror 8 for solar power generation was produced in the same manner, and a sample 8 as a reflector for solar power generation was produced using this.

The surface silica-coated cerium oxide was prepared in the same manner as the method for preparing the surface silica-coated iron oxide except that cerium oxide having an average particle size of 18 nm (manufactured by Big Chemie Japan Co., Ltd.) was used.

[Preparation of Sample 9: Example 9]
In the preparation of Sample 7, the surface silica-coated zinc oxide having an average particle size of 20 nm was used in place of the surface silica-coated iron oxide having an average particle size of 20 nm used for forming the UV absorbing layer of the film mirror 7 for solar power generation. The film mirror 9 for solar thermal power generation was produced in the same manner except that, and a sample 9 which was a reflector for solar thermal power generation was produced using this.

The surface silica-coated zinc oxide was prepared in the same manner as the above-described method for preparing surface silica-coated iron oxide, except that zinc oxide having an average particle size of 18 nm (manufactured by Sakai Chemical Industry Co., Ltd.) was used.

[Production of Sample 10: Example 10]
In the preparation of the sample 7, the surface silica-coated titanium oxide having an average particle size of 20 nm was used instead of the surface silica-coated iron oxide having an average particle size of 20 nm used for forming the UV absorbing layer of the film mirror 7 for solar power generation. Except for the above, a film mirror 10 for solar power generation was produced in the same manner, and a sample 10 as a reflector for solar power generation was produced using this.

The surface silica-coated titanium oxide was prepared in the same manner as the above-described method for preparing the surface silica-coated iron oxide, except that titanium oxide having an average particle size of 18 nm (Maxlite TS, manufactured by Showa Denko KK) was used.

[Preparation of Sample 11: Example 11]
In the formation of the UV absorbing layer of the film mirror 1 for solar power generation used for the production of the sample 1, the average particle size was changed to the condition that 15% by mass of iron oxide particles having an average particle size of 20 nm was added to the resin. The condition was changed such that 20 nm surface silica-coated zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) was added to 6% by mass with respect to the resin, and TINUNIN234 (manufactured by BASF Japan) was added as an organic UV absorber at 3% by mass with respect to the resin In the same manner, a film mirror 11 for solar power generation was produced in the same manner, and a sample 11 which was a reflector for solar power generation was produced using the film mirror 11.

[Preparation of Sample 12: Example 12]
A biaxially stretched polyester film (polyethylene terephthalate film, thickness 100 μm) was used as the resin substrate. On one side of the polyethylene terephthalate film, 3% by mass of TINUNIN234 (manufactured by BASF Japan) as an organic UV absorber is dissolved in a methylene chloride solvent so that the solid content ratio is 10: 2 with respect to the acrylic resin and the acrylic resin. And the coating liquid prepared by dispersing was coated by a gravure coating method to form an organic UV absorbing layer having a thickness of 30 μm which is arranged on the side opposite to the incident light side of the silver reflecting layer. Next, a silver reflective layer having a thickness of 80 nm is formed as a silver reflective layer on the formed organic UV absorbing layer by vacuum deposition, and a polyester resin and a toluene diisocyanate resin are formed on the silver reflective layer. In the resin mixed at a resin solid content ratio of 10: 2, glycol dimercaptoacetate is added as a corrosion inhibitor under the condition that the coating amount is 0.3 g / m ^2, and coating is performed by the gravure coating method. A corrosion prevention layer having a thickness of 0.1 μm was formed. Subsequently, surface silica-coated zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) having an average particle diameter of 6% by mass as an inorganic UV absorber with respect to the acrylic resin and the acrylic resin is 10: 2 in a solid content ratio. A coating solution dissolved and dispersed in a methylene chloride solvent was coated by a gravure coating method to form an inorganic UV absorbing layer having a thickness of 30 μm on the incident light side of the silver reflecting layer. Subsequently, Opstar (manufactured by JSR), which is a UV curable hard coat liquid, is applied onto the UV absorbing layer with an applicator and irradiated with UV light having a wavelength of 350 nm for 30 seconds, thereby forming a hard 10 μm thick A coat layer was formed.

Subsequently, an acrylic resin adhesive (manufactured by Showa Kogyo Co., Ltd.) with a thickness of 10 μm was coated as an adhesive layer on the surface of the polyethylene terephthalate film on the side opposite to the surface on which the hard coat layer was formed. Thus, a film mirror 12 for solar power generation having the layer configuration shown in FIG. 4 was produced.

Next, a 0.1 mm thick, 4 cm × 5 cm wide aluminum plate (manufactured by Sumitomo Light Metal Co., Ltd.) is pasted via the adhesive layer of the solar thermal power generation film mirror 12 produced above, and a solar thermal power generation reflection device Sample 12 was prepared.

[Preparation of Sample 13: Example 13]
In the film mirror 12 for solar thermal power generation, instead of the surface silica-coated zinc oxide having an average particle diameter of 20 nm, which is an inorganic UV absorber used for forming the inorganic UV absorbing layer (position 11 in FIG. 4), an organic Using 3% by mass of TINUNIN234 (manufactured by BASF Japan) as the UV absorber, the organic UV absorber layer 10 shown in FIG. 3 is used, and the organic UV absorber layer (position 10 shown in FIG. 4) is formed. In place of TINUNIN234, which was an organic UV absorber, 20 wt% surface silica-coated zinc oxide (manufactured by Sakai Chemical Industry Co., Ltd.) was used as the inorganic UV absorber, and the inorganic UV absorber layer 11 shown in FIG. Except that, a solar power generation film mirror 13 having the configuration shown in FIG. 3 was produced in the same manner, and a sample 13 as a solar thermal power generation reflection device was produced using this.

[Production of Sample 14: Comparative Example 1]
In the preparation of the sample 1, instead of the iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorption layer of the solar power generation film mirror 1, the average particle diameter of 20 nm and the refractive index. The film mirror 14 for solar power generation was produced in the same manner except that titanium oxide of 2.5 (manufactured by Sakai Chemical Industry Co., Ltd.) was used, and the sample 14 as a solar power generation reflection device was produced using this. .

[Production of Sample 15: Comparative Example 2]
In preparation of the sample 1, in place of the iron oxide particles having an average particle diameter of 20 nm and a refractive index of 2.4 used for forming the UV absorption layer of the film mirror 1 for solar power generation, 5 mass% as an organic UV absorber. Except for using TINUNIN234 (manufactured by BASF Japan Ltd.), a film mirror 15 for solar power generation was produced in the same manner, and a sample 15 as a reflector for solar power generation was produced using this.

<< Measurement of characteristic values of inorganic UV absorber used for production of film mirror for solar power generation >>
[Refractive index measurement of inorganic UV absorber]
A 10% by mass aqueous dispersion of an inorganic UV absorber was prepared. Subsequently, polyvinyl pyrrolidone was added to each aqueous dispersion so that the mass ratio with respect to the inorganic UV absorber was 1, this solution was spin-coated, dried at 120 ° C., and sodium D line (wavelength 589 nm) at 25 ° C. The refractive index at the wavelength of was measured using an ellipsometer VASE (Woolum). In addition, the refractive index was calculated | required as a refractive index of solid content from the volume fraction of contained solid content.

[Measurement of particle size of inorganic UV absorber]
A 0.01% by mass aqueous dispersion of an inorganic UV absorber was prepared. Subsequently, the particle size distribution of each aqueous dispersion was measured using LB-550 (manufactured by HORIBA), which is a dynamic light scattering particle shape measuring device, and the peak top value at this time was determined as the particle size.

<< Evaluation of each sample >>
About each produced said solar power generation reflective apparatus, evaluation of an initial state (initial regular reflectance), evaluation of light resistance (regular reflectance stability), and the weather resistance of the adhesion layer were performed according to the following method.

[Evaluation of initial state: Initial regular reflectance]
The spectrophotometer UV265 manufactured by Shimadzu Corporation was remodeled with an integrating sphere reflection accessory, and the incident light incident angle was adjusted to 5 ° with respect to the normal of the reflecting surface. The initial regular reflectance at a reflection angle of 5 ° before the deterioration treatment was measured. Evaluation was measured as an average reflectance from 350 nm to 700 nm.

6: Average value of regular reflectance is 85% or more 5: Average value of regular reflectance is 80% or more and less than 85% 4: Average value of regular reflectance is 75% or more, 80% 3: The average value of regular reflectance is 70% or more and less than 75% 2: The average value of regular reflectance is 65% or more and less than 70% 1: The average value of regular reflectance is Less than 65% [Evaluation of light resistance: regular reflectance stability]
Each sample whose initial specular reflectance was measured by the above method was irradiated with ultraviolet rays in an environment of 65 ° C. for 7 days using an I-Super UV tester manufactured by Iwasaki Electric Co., Ltd., and then the regular reflectance was measured by the above method. The average value of the regular reflectance after ultraviolet irradiation when the initial regular reflectance before ultraviolet irradiation was 100% was calculated, and the light resistance was evaluated according to the following criteria.

6: The average value of regular reflectance after ultraviolet irradiation is 85% or more 5: The average value of regular reflectance after ultraviolet irradiation is 80% or more and less than 85% 4: Regular reflection after ultraviolet irradiation The average value of the rate is 75% or more and less than 80% 3: The average value of the regular reflectance after ultraviolet irradiation is 70% or more and less than 75% 2: The average value of the regular reflectance after ultraviolet irradiation Is 65% or more and less than 70% 1: The average value of the regular reflectance after ultraviolet irradiation is less than 65% [Evaluation of weather resistance of adhesive layer]
After performing ultraviolet irradiation for 7 days in an environment of 65 ° C. using an I-superior eye super UV tester manufactured by Iwasaki Electric Co., Ltd., the adhesion of the adhesive layer was evaluated according to a grid cellophane tape peeling test of JIS K5400. That is, the sample surface after forced deterioration was cut into a grid pattern with a 1 mm interval with a cutter knife, peeled off after applying cellophane tape (manufactured by Nichiban Co., Ltd.), and the ratio of the peeled portion was measured. The weather resistance of the adhesive layer was evaluated.

A: The ratio of the film peeling part is less than 2.0% after the deterioration test. ○: The ratio of the film peeling part is 2.0% or more and less than 3.0% after the deterioration test. X: The ratio of the film peeling part is 3 after the deterioration test. 0.0% or more [Results of demonstration of technical features]
The results of evaluation for each sample according to the above method will be sequentially described below in a combination that can determine the effect of the construction technology of each solar power generation reflection device (solar power generation film mirror).

(Confirmation of the effect of the average particle diameter and refractive index of the inorganic UV absorber applied to the UV absorbing layer)
Using the produced samples 1 to 6 (Examples 1 to 6 of the present invention) and samples 14 and 15 (Comparative Examples 1 and 2), the average particle size of the inorganic UV absorber applied to the UV absorbing layer defined in the present invention Table 1 shows the verification results of the effects of diameter and refractive index.

As is clear from the results shown in Table 1, Samples 1 to 6 (invention examples 1 to 6) having a UV absorption layer containing an inorganic UV absorber having a refractive index of 2.4 or less as defined in the present invention are: It is clear that the samples 14 and 15 as comparative examples are excellent in the initial state (initial regular reflectance), light resistance (regular reflectance stability), and weather resistance (adhesion) of the adhesive layer. This is because the sample of the present invention uses an inorganic UV absorber having a refractive index of 2.4 or less to suppress a decrease in reflectance due to light scattering, and at the same time, UV-B region (290-320 nm) that causes deterioration of the adhesive layer. It is a result which shows that the light ray of) can be absorbed effectively. In addition, samples 1 to 3 using an inorganic UV absorber having an average particle diameter of 20 nm are superior in reflection stability to samples 4 to 6 using an inorganic UV absorber having an average particle diameter of 500 nm. I understand. That is, the smaller the average particle diameter, the lower the regular reflectance due to light scattering of the inorganic UV absorber particles.

(Confirmation of effect by surface coating of inorganic UV absorber applied to UV absorbing layer)
Samples 1 to 3 (Invention Examples 1 to 6) and Samples 7 to 10 (Invention Examples 7 to 10) prepared as described above were used for the inorganic UV absorber applied to the UV absorbing layer defined in the present invention. Table 2 shows the verification results of the surface coating effect.

As is apparent from the results shown in Table 2, the samples 7 to 10 using the inorganic UV absorber particles coated on the surface were deteriorated compared to the samples 1 to 3 using the inorganic UV absorber particles not coated. It can be seen that the variation in regular reflectance after the treatment is small and a high regular reflectance is maintained. This result demonstrated that the photocatalytic activity of the inorganic UV absorber particles can be suppressed and the deterioration of the adjacent resin can be suppressed by coating the surface of the inorganic UV absorber particles with silica.

(Effects of combined use of inorganic UV absorber and organic UV absorber in UV absorbing layer)
Sample 11 (invention example 11) in which an inorganic UV absorber and an organic UV absorber are used in combination in the same UV absorption layer prepared above, sample 3 (example 3) using only an inorganic UV absorber, Table 3 shows the effects obtained by using the sample 15 (Comparative Example 2) using only the organic UV absorber and combining the inorganic UV absorber and the organic UV absorber in the same UV absorbing layer.

Sample 11 shown in Table 3 (Example 11) is a film mirror for solar power generation having a UV absorber layer containing the inorganic UV absorber and the organic UV absorber shown in FIG. As is clear from the results shown in Table 3, the combined use of an inorganic UV absorber and an organic UV absorber reduces the amount of inorganic UV absorber that tends to cause a decrease in reflectance due to light scattering. As a result, it can be seen that the change in regular reflectance after the deterioration treatment is small, and a high regular reflectance can be maintained.

(Effect by independently forming an inorganic UV absorber layer and an organic UV absorber layer)
Using the samples 12 and 13 in which the inorganic UV absorber layer and the organic UV absorber layer are arranged at independent positions, and the sample 9 in which only the inorganic UV absorber layer is formed, the inorganic UV absorber layer and the organic UV absorber are formed. Table 4 shows the effect of forming the absorbent layer independently.

As is clear from the results shown in Table 4, Example 12 and Example 13 having a configuration in which an inorganic UV absorbing layer containing an inorganic UV absorber and an organic UV absorbing layer containing an organic UV absorber are separately provided are FIG. 4 is a film mirror for solar power generation having the layer configuration shown in FIGS. 4 and 3. FIG. In Example 12 having the configuration shown in FIG. 4, the amount of the inorganic UV absorber used can be reduced for the same reason as in Example 11, and thus it can be seen that the reflectance is higher. Moreover, in Example 13 which is a structure shown in FIG. 3, it has the structure which has arrange | positioned the inorganic UV absorber layer 11 containing the inorganic UV absorber in the anti-incident light side rather than a silver reflection layer, and coloration arises so that it may occur. Even if a large amount of inorganic UV absorber is added, there is no problem. In fact, in Example 13, when the amount of the inorganic UV absorber used was increased, the result that the adhesion layer peeling resistance was further improved was obtained.

DESCRIPTION OF SYMBOLS 1 Solar power film mirror 2 Hard coat layer 3, 3 'UV absorption layer 4 Corrosion prevention layer 5 Silver reflection layer 6 Resin support layer 7 Adhesive layer 8 Inorganic UV absorber 9 Organic UV absorber 10 Organic UV absorber layer 11 Inorganic UV absorber layer

Claims

It has one or more UV absorbing layers containing an inorganic UV absorber having a refractive index of 2.4 or less, and a silver reflecting layer composed of silver, and an adhesive layer on the side opposite to the incident light with respect to the silver reflecting layer A film mirror for solar power generation, comprising:
The film mirror for solar power generation according to claim 1, wherein the inorganic UV absorber is a fine particle having an average particle diameter of 10 nm or more and 100 nm or less.
The film mirror for solar power generation according to claim 1, wherein the inorganic UV absorber is a fine particle having a surface-coated average particle diameter of 10 nm or more and 100 nm or less.
The film mirror for solar power generation according to any one of claims 1 to 3, wherein the UV absorbing layer further contains an organic UV absorber.
Furthermore, it has an organic UV absorber layer containing an organic UV absorber, The film mirror for solar power generation of any one of Claim 1 to 4 characterized by the above-mentioned.
The organic UV absorber layer is disposed on the incident light side with respect to the silver reflective layer, and the inorganic UV absorber layer is disposed on the side opposite to the incident light with respect to the silver reflective layer. 5. A film mirror for solar power generation according to 5.
The inorganic UV absorber layer is disposed on the incident light side with respect to the silver reflective layer, and the organic UV absorber layer is disposed on the side opposite to the incident light with respect to the silver reflective layer. Item 6. The film mirror for solar power generation according to Item 5.
It is a manufacturing method of the film mirror for solar power generation which manufactures the film mirror for solar power generation of any one of Claim 1 to 7, Comprising: A silver reflective layer is formed by vapor deposition of silver, The solar thermoelectric power generation characterized by the above-mentioned Film mirror manufacturing method.
A reflector for solar power generation, comprising the film mirror for solar power generation according to any one of claims 1 to 7 bonded to a support via an adhesive layer.