WO2015115278A1 - Film mirror and reflective device for solar thermal power generation - Google Patents

Abstract

The present invention provides a film mirror which has a surface having excellent scratch resistance. The present invention is a film mirror which comprises a resin base, a light-reflecting layer, a hard coat layer that is positioned closest to the light incident side, and a hard-coat-adjacent layer that is arranged adjacent to the hard coat layer. The hard-coat-adjacent layer has a Young's modulus of 4.5 GPa or more.

Description

Reflector for film mirror and solar power generation

The present invention relates to a film mirror and a solar power generation reflector.

In recent years, global warming has developed into a more serious situation. The main cause is thought to be atmospheric carbon dioxide (CO ₂ ) released from fossil fuels. Therefore, it is considered that it will not be allowed to continue using fossil fuels in the near future. On the other hand, the depletion of oil and natural gas, once thought to be inexhaustible, has become a reality due to the increase in energy demand accompanying the rapid economic growth of so-called developing countries such as China, India and Brazil. Yes.

Solar energy can be considered as one of the stable and abundant natural energy as an alternative energy for fossil fuel. In particular, the vast desert spreads near the equator, which is called the world's sun belt, and the solar energy that falls down here is truly inexhaustible. In this regard, it is believed that energy of as much as 7,000 GW can be obtained using only a few percent of the desert that extends to the southwestern United States. It is also believed that using only a few percent of the Arabian peninsula and the deserts of North Africa can cover all the energy used by all mankind.

Thus, although solar energy is a very powerful alternative energy, in order to utilize it in social activities, (1) low energy density of solar energy and (2) storage of solar energy And the difficulty of transport 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 concentrator.

Since the light collecting device is exposed to ultraviolet rays, heat, wind and rain, sand storms, etc. by sunlight, conventionally, a glass mirror has been used for the light collecting device. Glass mirrors are highly durable to the environment, but they can be damaged during transportation, and the weight of the glass mirrors can increase the strength of the frame on which the mirrors are installed, which increases plant construction costs. was there.

On the other hand, resin-made reflective sheets (film mirrors) have been put to practical use as reflective sheets for backlight units of liquid crystal displays. When applied to solar reflective mirrors, damage due to external pressure and the heavy weight of glass mirrors are disadvantages. This problem can be solved.

International Publication No. 2011/096309 has a resin base material, a silver reflective layer thereon, and an outermost layer made of a material having a metalloxane skeleton on the outermost side on the light source side of the silver reflective layer. A film mirror is disclosed in which the contact angle of water and the coefficient of dynamic friction of the outermost layer made of a material having a skeleton are in a specific range.

Since the film mirror is installed outdoors, it is necessary to clean the surface with a cleaning tool such as a brush in order to remove sand and dust. However, in the film mirror described in International Publication No. 2011/096309, the scratch resistance of the surface at the time of cleaning is not sufficient, and the phenomenon that the regular reflectance after the cleaning is decreased is observed. There was a need for further improvement.

Therefore, an object of the present invention is to provide a film mirror having excellent surface scratch resistance.

The present inventor conducted extensive research. As a result, it has been found that the above problem can be solved by a film mirror in which a hard coat adjacent layer having a Young's modulus in a specific range is provided adjacent to the outermost hard coat layer on the light incident side. The invention has been completed.

The above-described problem of the present invention includes a resin base material and a light reflection layer, a hard coat layer located closest to the light incident side, and a hard coat adjacent layer provided adjacent to the hard coat layer, This is achieved by a film mirror in which the Young's modulus of the coat adjacent layer is 4.5 GPa or more.

It is a schematic sectional drawing which shows an example of a structure of the film mirror of this invention, 10 is a film mirror, 11 is a hard-coat layer, 12 is a hard-coat adjacent layer, 13 is a resin base material, 14 Is a light reflection layer, 15 is a resin coat layer (corrosion prevention layer), and 16 is an adhesive layer.

The present invention has a resin base material and a light reflection layer, a hard coat layer located closest to the light incident side, and a hard coat adjacent layer provided adjacent to the hard coat layer, and the hard coat adjacent layer This film mirror has a Young's modulus of 4.5 GPa or more. The film mirror having such a configuration is excellent in surface scratch resistance (scratch resistance).

Since the film mirror is installed outdoors, it is necessary to clean the surface with a strong force using a cleaning tool such as a brush in order to remove sand and dust. Due to the strong force at the time of cleaning, the light reflecting layer formed from silver, aluminum, etc. is locally deformed and the surface roughness is increased, and after cleaning, the reflected light is scattered and the regular reflectance is reduced, There is a problem that the light collection efficiency decreases.

For such a problem, the film mirror of the present invention includes a hard coat adjacent layer having a Young's modulus of 4.5 GPa or more adjacent to the hard coat layer provided on the outermost surface on the light incident side. By having such a configuration, local deformation of the light reflecting layer at the time of cleaning can be suppressed, an increase in the surface roughness of the light reflecting layer can be suppressed, and the scratch resistance of the surface can be improved. Further, this can suppress a decrease in regular reflectance after surface cleaning, and can prevent a decrease in light collection efficiency.

Hereinafter, preferred embodiments of the present invention will be described. In addition, this invention is not limited only to the following embodiment.

In this specification, “X to Y” indicating a range means “X or more and Y or less”. Unless otherwise specified, operations and physical properties are measured under conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

[Structure of film mirror]
The overall configuration of the film mirror of the present invention will be described with reference to the drawings. In addition, the dimension ratio of drawing is exaggerated on account of description, and may differ from an actual ratio.

FIG. 1 is a diagram schematically showing a cross section of a film mirror according to an embodiment of the present invention. The film mirror 10 shown in FIG. 1 has a hard coat layer 11, a hard coat adjacent layer 12, a resin base material 13, a light reflecting layer 14, a resin coat layer (corrosion prevention layer) 15, and an adhesive layer 16 in this order from the light incident side. Has been.

The total thickness of the film mirror according to the present invention is preferably from 80 to 300 μm, more preferably from 80 to 200 μm, and even more preferably from 80 to 170 μm from the viewpoints of prevention of bending, regular reflectance, handling properties, and the like. In addition, the outermost surface layer on the light incident side of the film mirror, that is, the center line average roughness (Ra) of the hard coat layer is 3 nm or more and 20 nm or less, so that scattering of reflected light can be prevented and light collection efficiency is improved. It is preferable from the viewpoint.

Hereinafter, the configuration of the film mirror of the present invention will be described in detail.

[Resin substrate]
As a resin base material, the film containing conventionally well-known various resin can be used. Examples of the resin include, for example, polycarbonate, polyarylate, polysulfone, polyethersulfone, polyethylene terephthalate, polyethylene naphthalate, polyester such as modified polyester, polyethylene, polypropylene, cellulose, diacetylcellulose, triacetylcellulose, cellulose acetate propionate. , Cellulose acetate butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polystyrene, syndiotactic polystyrene, cycloolefin polymer, polynorbornene, polymethylpentene, polyether ketone, polyether ether Ketone, polyether ketone imide, polyamide, polyimide, polysulfone, polyether Rusuruhon, fluororesin, polymethyl methacrylate, and acrylic resins. These resins may be used alone or in combination of two or more. The resin base material may have a single layer structure or a multilayer structure of two or more layers. In the case of a multilayer structure, the resin contained in each layer may be the same or different. The resin substrate may be a film manufactured by melt casting film formation or a film manufactured by solution casting film formation. The resin substrate may be an unstretched film or a stretched film.

When the resin substrate is located farther from the light incident side than the light reflecting layer, it is difficult for ultraviolet rays to reach the resin substrate. In particular, when an ultraviolet absorber is contained in a layer or the like closer to the light incident side than the resin base material, the ultraviolet light hardly reaches the resin base material. Therefore, the resin base material can be used even if it is a resin that easily deteriorates with respect to ultraviolet rays. From such a viewpoint, a polyester film such as polyethylene terephthalate can be used as the resin base material.

Of course, the resin substrate may contain an ultraviolet absorber. Such an ultraviolet absorber is not particularly limited, and examples of the organic type include ultraviolet absorbers such as benzophenone type, benzotriazole type, phenyl salicylate type, triazine type, benzoate type, etc. Examples thereof include titanium oxide, zinc oxide, cerium oxide, and iron oxide. In order to reduce the problem of bleeding out when a large amount of ultraviolet absorber is contained, it is preferable to use a polymeric ultraviolet absorber having a molecular weight of 1000 or more. Preferably, the molecular weight is 1000 or more and 3000 or less. These ultraviolet absorbers can be used alone or in combination of two or more. As specific examples of the ultraviolet absorber, the compounds described in paragraphs “0038” to “0042” of JP2012-232538A can be used.

The thickness of the resin base material can be appropriately selected according to the type and purpose of the resin. For example, it is generally in the range of 10 to 250 μm, preferably 20 to 200 μm.

[Light reflection layer]
The light reflecting layer according to the present invention is a layer made of metal or the like having a function of reflecting sunlight. The surface reflectance of the light reflection layer is preferably 80% or more, more preferably 90% or more. The light reflecting layer is preferably formed of a material containing at least one element selected from the element group consisting of aluminum, silver, chromium, copper, nickel, titanium, magnesium, rhodium, platinum and gold. Of these, aluminum or silver is preferably the main component from the viewpoint of reflectance, corrosion resistance, etc., more preferably aluminum or silver, and particularly preferably silver.

Two or more such metal thin films may be formed. Further, a layer made of a metal oxide such as SiO ₂ and TiO ₂ may be provided in this order on the light reflecting layer to further improve the reflectance.

For example, as a method for forming the light reflecting layer according to the present invention, either a wet method or a dry method can be used.

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

On the other hand, the dry method is a general term for a vacuum film forming method, and specifically includes 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. As a manufacturing method of the film mirror of this invention, it is preferable to form a light reflection layer by a vapor deposition method.

When using the dry method, the light reflecting layer is preferably formed on a resin film. Examples of the resin film include, for example, polyesters such as polycarbonate, polyarylate, polysulfone, polyethersulfone, polyethylene terephthalate, and polyethylene naphthalate, polyethylene, polypropylene, cellulose, diacetylcellulose, triacetylcellulose, and cellulose acetate propio. Nate, cellulose acetate butyrate, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, polystyrene, syndiotactic polystyrene, cycloolefin polymer, polynorbornene, polymethylpentene, polyether ketone, polyether Includes resins such as ketone imide, polyamide, fluororesin, polymethyl methacrylate, acrylic resin Irumu can be mentioned. These resins may be used alone or in combination of two or more. The resin film may have a single layer structure or a multilayer structure of two or more layers. In the case of a multilayer structure, the resin contained in each layer may be the same or different. The resin film may be an unstretched film or a stretched film. The resin film may be a resin substrate constituting the film mirror of the present invention. That is, a light reflection layer may be formed on the resin base material described above by a dry method to form the resin base material and the light reflection layer according to the present invention.

The thickness of the light reflecting layer is preferably 10 to 200 nm, more preferably 30 to 150 nm, from the viewpoint of reflectivity and the like.

When the light reflecting layer is made of silver, when the light reflecting layer is formed, the light reflecting layer is formed by heating and baking a coating film containing a silver complex compound from which a ligand can be vaporized / desorbed. May be.

“Silver complex compound having a ligand that can be vaporized / desorbed” has a ligand for stably dissolving silver in a solution, but the ligand is removed by removing the solvent and heating and firing. Is a silver complex compound that can be thermally decomposed into CO ₂ or a low molecular weight amine compound, vaporized / desorbed, and only metallic silver remains.

Examples of such complexes are described in various publications such as JP-T 2009-535661, JP-T 2010-500475, and the like. Further, a complex obtained by the production method described in paragraphs “0080” to “0100” of JP2012-232538A can be used.

When a silver complex compound is used, the silver complex compound is contained in the silver coating liquid composition, and a coating film containing the complex according to the present invention is formed on the resin film by coating the silver complex compound. That is, it is preferable to form a silver reflective layer by forming a coating film on a resin film using a silver complex compound and then baking the coating film at a temperature in the range of 80 to 250 ° C. More preferably, it is within the range of 100 to 220 ° C, and further preferably within the range of 120 to 200 ° C. There is no restriction | limiting in particular as a heat baking means, What is generally used can be applied.

The light reflecting layer may be on the light incident side with respect to the resin base material, or may be on the side opposite to the light incident side.

[Hard coat layer]
In the film mirror of the present invention, the hard coat layer is provided on the outermost surface on the light incident side for the purpose of preventing the film mirror surface from being damaged or adhering to the surface. The thickness of the hard coat layer is preferably 0.05 to 10 μm, preferably 1 to 10 μm, from the viewpoint of preventing the film mirror from warping while obtaining sufficient scratch resistance. More preferred.

The material for forming the hard coat layer is not particularly limited as long as transparency, weather resistance, hardness, mechanical strength, and the like can be obtained. Specifically, resin materials such as acrylic resin, urethane resin, melamine resin, epoxy resin, organic silicate compound, and silicone resin; inorganic such as silicon oxide, aluminum oxide, silicon nitride, aluminum nitride, lanthanum oxide, lanthanum nitride, and polysilazane It can be composed of materials and the like. In particular, silicone resin and acrylic resin 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, a modifier, etc. as needed. The active energy ray curable acrylic resin and the thermosetting acrylic resin are included in the hard coat layer in the form of a cured product after the curing treatment.

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 are manufactured by Mitsubishi Rayon Co., Ltd. (trade name “Diabeam (registered trademark)” series, etc.), Nagase Sangyo Co., Ltd. (trade name “Denacol (registered trademark)” Series, etc.), Shin-Nakamura Chemical Co., Ltd .; (trade name “NK Ester” series, etc.), DIC Corporation; (trade name “UNIDIC®” series, etc.), Toagosei Co., Ltd. (trade name) "Aronix (registered trademark)" series, etc.), manufactured by NOF Corporation; (trade name "Blemmer (registered trademark)" series, etc.), Nippon Kayaku Co., Ltd. (trade name "KAYARAD (registered trademark)" series, etc.) , Kyoeisha Chemical Co., Ltd .; (product name “light ester” series, “light acrylate” series, etc.) can be used.

More specifically, for example, a resin curable by electron beam or ultraviolet irradiation, a thermosetting resin, or the like can be used, and in particular, a thermosetting silicone hard coat material composed of a partially hydrolyzed oligomer of an alkoxysilane compound, A hard coat material composed of a thermosetting polysiloxane resin, an ultraviolet curable acrylic hard coat material composed of an acrylic compound having an unsaturated group, or a thermosetting inorganic material is preferred. As materials that can be used for the hard coat layer, an aqueous colloidal silica-containing acrylic resin (Japanese Patent Laid-Open No. 2005-66824), a polyurethane-based resin composition (Japanese Patent Laid-Open No. 2005-110918), and an aqueous silicone compound as a binder. Resin film used (Japanese Patent Laid-Open No. 2004-142161), photocatalytic oxide-containing silica film such as titanium oxide, or photocatalytic film such as alumina, titanium oxide or niobium oxide having a high aspect ratio (Japanese Patent Laid-Open No. 2009-62216) , Photocatalyst-containing fluororesin coating material (Pierex Technologies Co., Ltd.), organic / inorganic polysilazane film, organic / inorganic polysilazane using a hydrophilization promoter (AZ Electronics Materials Co., Ltd.), etc. it can. Resins that are cured by irradiation with electron beams or ultraviolet rays or thermosetting resins are included in the hard coat layer in the form of a cured product after being subjected to a curing treatment.

In the hard coat layer, 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, ultraviolet absorbers, surfactants, leveling agents, antistatic agents, and the like can be used.

In addition, with regard to specific materials used for the hard coat layer and methods for forming the hard coat layer, the materials and formation methods described in paragraphs “0129” to “0168” of JP2012-232538A are appropriately employed. Can do.

The dynamic friction coefficient of the hard coat layer is preferably 0.4 or less, and more preferably 0.25 or less. Within this range, the scratch resistance of the film mirror surface is further improved. The dynamic friction coefficient can be controlled by controlling the type of material for forming the hard coat layer, the addition of a surface modifier or particles to the hard coat adjacent layer described later, and the like. Moreover, this dynamic friction coefficient can be measured by the method as described in an Example.

Further, the center line average roughness (Ra) of the hard coat layer is preferably 3 nm or more and 20 nm or less from the viewpoint of preventing scattering of reflected light and increasing the light collection efficiency. The centerline average roughness (Ra) can be determined by a measurement method based on JIS B0601: 1982.

[Hard court adjacent layer]
The film mirror of the present invention has a hard coat adjacent layer adjacent to the hard coat layer on the side opposite to the light incident side of the hard coat layer. The Young's modulus of the hard coat adjacent layer is 4 GPa or more. By providing the hard coat adjacent layer having such a Young's modulus, the film mirror of the present invention has excellent scratch resistance.

The material constituting the hard coat adjacent layer is not particularly limited, but preferably includes a resin material having optical transparency and fine particles for adjusting Young's modulus.

The resin material used for the hard coat adjacent layer is not particularly limited, and various conventionally known synthetic resins that can maintain transparency when a thin film is formed can be used. For example, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyethylene esters, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate, cellulose esters such as cellulose acetate phthalate, cellulose nitrate, or the like Derivatives of polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide, polyether sulfone, polysulfone, polyether ketone imide, polyamide, fluororesin, Nylon, (meth) acrylic resin, polyarylate Or cycloolefin resins. These resin materials can be used alone or in combination of two or more. These resin materials may be commercially available products or synthetic products. Examples of commercially available products include EMB457 (manufactured by Mitsubishi Rayon Co., Ltd.), Arton (registered trademark, manufactured by JSR Corporation), Apel (registered trademark, manufactured by Mitsui Chemicals, Inc.), and the like.

Among the resin materials exemplified above, (meth) acrylic resin is suitably used as the material for forming the hard coat adjacent layer. When the hard coat adjacent layer contains a (meth) acrylic resin, since the (meth) acrylic resin is hard, a plasticizer may be included for the purpose of obtaining a hard coat adjacent layer that is not easily damaged. Preferable examples of the plasticizer include acrylic rubber, butyl rubber and butyl acrylate. Here, the addition amount of the plasticizer is not particularly limited, but is preferably about 10 to 25% by mass with respect to the resin material in consideration of desired flexibility and the like.

More preferably, the hard coat adjacent layer is formed mainly of a methacrylic resin. The methacrylic resin is a polymer mainly composed of a methacrylic acid ester, and may be a homopolymer of a methacrylic acid ester, 50% by mass or more of the methacrylic acid ester and 50% by mass or less of the other monomers. The copolymer may be used. Here, as the methacrylic acid ester, an alkyl ester of methacrylic acid is usually used. A particularly preferred methacrylic resin is polymethyl methacrylate (PMMA) resin.

More preferable monomer composition of the methacrylic resin is 50 to 100% by mass of the alkyl methacrylate and 0 to 50% by mass of the acrylic acid alkyl ester based on all monomers, and 0 to 50% of the other monomers. 49% by mass, more preferably 50 to 100% by mass of alkyl methacrylate, 0 to 50% by mass of acrylic ester, and 0 to 49% by mass of other monomers.

Here, examples of the alkyl methacrylate include methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and the like. The alkyl group in the ester moiety usually has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. Of these, methyl methacrylate is preferably used.

Examples of alkyl acrylate esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. The alkyl group in the ester moiety usually has 1 to 8 carbon atoms, preferably 1 carbon atom. ~ 4.

The monomer other than methacrylic acid alkyl ester and acrylic acid alkyl ester may be a monofunctional monomer, that is, a compound having one polymerizable carbon-carbon double bond in the molecule. Although it may be a functional monomer, that is, a compound having at least two polymerizable carbon-carbon double bonds in the molecule, a monofunctional monomer is preferably used. Examples of this monofunctional monomer include aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene, and alkenyl cyanide compounds such as acrylonitrile and methacrylonitrile. Examples of polyfunctional monomers include polyunsaturated carboxylic acid esters of polyhydric alcohols such as ethylene glycol dimethacrylate, butanediol dimethacrylate, trimethylolpropane triacrylate, allyl acrylate, allyl methacrylate, and cinnamon. Alkenyl esters of unsaturated carboxylic acids such as allyl acid, polyalkenyl esters of polybasic acids such as diallyl phthalate, diallyl maleate, triallyl cyanurate, triallyl isocyanurate, aromatic polyalkenyl compounds such as divinylbenzene, etc. Can be mentioned.

In addition, as for said methacrylic acid alkyl ester, acrylic acid alkyl ester, and monomers other than these, respectively, you may use those 2 or more types as needed.

The glass transition temperature of the methacrylic resin is preferably 40 ° C. or higher, more preferably 60 ° C. or higher, from the viewpoint of heat resistance of the film. This glass transition temperature can be appropriately set by adjusting the type of monomer and the ratio thereof.

As the methacrylic resin, a commercially available product or a synthetic product may be used. When a synthetic product is used, the monomer component can be obtained by polymerizing the monomer component by a method such as suspension polymerization, emulsion polymerization, or bulk polymerization. At that time, in order to obtain a suitable glass transition temperature, or to obtain a viscosity showing a formability to a suitable film, it is preferable to use a chain transfer agent during the polymerization. The amount of the chain transfer agent may be appropriately determined according to the type of monomer and the ratio thereof.

The content of the resin material in the hard coat adjacent layer is preferably 50 to 90% by mass with respect to the entire hard coat adjacent layer.

The hard coat adjacent layer preferably contains fine particles for the purpose of adjusting the Young's modulus within the range of the present invention.

Examples of the fine particles contained in the hard coat adjacent layer include metal powders such as gold, silver, nickel, copper, lead, aluminum, iron powder, iron oxide, and iron sand; aluminum oxide, zinc oxide, magnesium oxide, silicon oxide (silica) ), Silicate, aluminum nitride, boron nitride, silicon nitride, aluminum hydroxide, magnesium hydroxide, metal compound particles with aluminum oxynitride; silicon carbide, tungsten carbide, ceria, titania, zirconia, graphene, diamond-like carbon, Carbon-based materials such as diamond fine particles, nanodiamonds, and carbon nanotubes: particles made of polyolefin resins such as polyethylene and polypropylene, (meth) acrylic resins such as polymethyl methacrylate, resins such as epoxy resins and polyimide resins; . These fine particles can be used alone or in combination of two or more. Among these, nanodiamond, silica, aluminum, or acrylic resin particles are preferable.

The content of the fine particles in the hard coat adjacent layer is not particularly limited as long as the Young's modulus can be controlled within the range of the present invention.

The hard coat adjacent layer may contain an ultraviolet absorber in order to prevent deterioration due to ultraviolet rays. Although there is no particular limitation on the contained ultraviolet absorber, for example, an organic ultraviolet absorber such as thiazolidone, benzotriazole, acrylonitrile, benzophenone, aminobutadiene, triazine, phenyl salicylate, benzoate, etc. Alternatively, fine powder type ultraviolet blocking agents such as cerium oxide and magnesium oxide, titanium oxide, zinc oxide, iron oxide and the like can be mentioned, and organic ultraviolet absorbers are particularly preferable.

In addition, the hard coat adjacent layer may contain an antioxidant in order to prevent deterioration. The antioxidant is not particularly limited, and examples thereof include phenolic antioxidants, hindered amine antioxidants, thiol antioxidants, and phosphite antioxidants. More specifically, compounds described in paragraphs “0048” to “0052” of JP2012-232538A can be used.

Further, the antioxidant and the light stabilizer may be used in combination. Examples of the light stabilizer include nickel-based ultraviolet light stabilizers. More specifically, compounds described in paragraph “0053” of JP2012-232538A can be used.

It is also possible to add an antistatic agent to the hard coat adjacent layer to impart antistatic performance. Moreover, you may add a phosphorus-type flame retardant to a hard-coat adjacent layer.

Furthermore, the hard coat adjacent layer may contain a surface modifier. By including the surface modifier, the dynamic friction coefficient of the adjacent hard coat layer can be reduced. As the surface modifier, a commercially available product may be used, or a synthetic product may be used. Examples of commercially available products include, for example, fluorine-based products such as MegaFac (registered trademark) RS-76E, MegaFac (registered trademark) F-552, MegaFac (registered trademark) F-554 (above, manufactured by DIC Corporation), etc. Examples thereof include silicon surface modifiers such as surface modifiers, BYK (registered trademark) -370, BYK (registered trademark) -377 (manufactured by BYK Japan KK). These surface modifiers can be used alone or in combination of two or more. The addition amount of the surface modifier is not particularly limited, but is preferably 0.03 to 1% by mass with respect to the resin material contained in the hard coat adjacent layer.

The hard coat adjacent layer may contain a curing agent such as 1,6-hexamethylene isocyanate or tolylene diisocyanate. These curing agents can be used alone or in admixture of two or more. The addition amount of the curing agent is not particularly limited, but is preferably 1 to 12% by mass with respect to the resin material contained in the hard coat adjacent layer. When the curing agent is included, the hard coat adjacent layer is in a form including a cured product of the resin material.

Furthermore, additives such as a surfactant, a leveling agent and an antistatic agent can be added to the hard coat adjacent layer as long as the effects of the present invention are not impaired.

The method for forming the hard coat adjacent layer is not particularly limited. For example, after preparing the coating liquid for forming the hard coat adjacent layer by mixing the above resin material, fine particles and other components as required in an organic solvent. And a method of applying and drying the coating solution. As a specific method of coating, various conventionally used coating methods such as spray coating, spin coating, bar coating, gravure coating, reverse coating, and die coating can be used.

Examples of the organic solvent used in the coating solution include methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, methyl propionate, ethyl propionate, butyl propionate, methyl lactate, ethyl lactate, butyl lactate, 3- Esters such as methyl methoxypropionate, ethyl 3-methoxypropionate, methyl 3-ethoxypropionate, ethyl 3-ethoxypropionate, methyl acetoacetate and ethyl acetoacetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone Aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; Aliphatic hydrocarbons such as hexane, cyclohexane and octane; Ami such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone Kind, and the like. These organic solvents can be used alone or in combination of two or more.

By forming the hard coat adjacent layer by such a coating method, the smoothness of the hard coat adjacent layer can be improved. Specifically, the center line average roughness (Ra) of the hard coat adjacent layer formed by the coating method is preferably 3 nm or more and 20 nm or less. In other words, if the center line average roughness satisfies this value, it can be considered that the hard coat adjacent layer, not the hard coat adjacent layer produced by melt film formation, is provided by coating.

The thickness (dry film thickness) of the hard coat adjacent layer is not particularly limited, but is preferably 5 to 150 μm, more preferably 10 to 100 μm, and further preferably 20 to 80 μm. If it is such thickness, sufficient translucency can be ensured, and a solvent can fully evaporate by drying at the time of film formation, and it is preferable from a viewpoint of productivity.

The Young's modulus of the hard coat adjacent layer is 4.5 GPa or more. When the Young's modulus is less than 4.5 GPa, the scratch resistance of the film mirror surface is lowered. The Young's modulus is preferably 20 GPa or less, and more preferably 4.5 GPa or more and 7 GPa or less.

The Young's modulus of the hard coat adjacent layer can be controlled by controlling the type of resin material, the type and amount of fine particles and surface modifier. The Young's modulus of the hard coat adjacent layer can be measured by the method described in the examples.

The film mirror of the present invention may have various layers such as an adhesive layer, a resin coat layer, a gas barrier layer, an anchor layer, an adhesive layer, and a release layer as necessary. Hereinafter, these layers will be described.

[Adhesive layer]
The adhesive layer is not particularly limited as long as it has a function of improving the adhesion between the layers. Adhesion or adhesion may be used. Preferably, it is a layer for adhering the hard coat layer and the resin coat layer. Adhesive layer has adhesion to adhere layers, heat resistance that can withstand heat when forming light reflection layer by vacuum deposition method, etc., and smoothness to bring out high reflection performance inherent to light reflection layer It is preferable to have.

The adhesive layer may consist of only one layer or may consist of a plurality of layers. The thickness of the adhesive layer is preferably 1 to 10 μm, more preferably 3 to 8 μm, from the viewpoints of adhesion, smoothness, reflectance of the reflecting material, and the like.

When the adhesive layer is made of a resin, the material is not particularly limited, and a single material such as polyester resin, polyurethane resin, acrylic resin, melamine resin, epoxy resin, polyamide resin, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer resin, etc. Alternatively, these mixed resins can be used. From the viewpoint of weather resistance, a mixed resin of a polyester resin and a melamine resin or a mixed resin of a polyester resin and a urethane resin is preferable, and a thermosetting resin in which a curing agent such as isocyanate is mixed such that an isocyanate is mixed with an acrylic resin. This is more preferable. 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.

Further, when the adhesive layer is made of a metal oxide, it can be formed by various vacuum film forming methods such as silicon oxide, aluminum oxide, silicon nitride, aluminum nitride, lanthanum oxide, and lanthanum nitride. For example, there are 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.

[Resin coat layer (corrosion prevention layer)]
The film mirror of the present invention may have a resin coat layer (corrosion prevention layer) so as to be adjacent to the light reflection layer. When the resin coat layer is adjacent to the light reflecting layer, the resin coat layer preferably contains a corrosion inhibitor so as to prevent corrosion of the light reflecting layer.

The resin coat layer may consist of only one layer or a plurality of layers. The thickness of the resin coat layer is preferably 1 to 10 μm, more preferably 2 to 8 μm.

Examples of the binder for the resin coating layer include cellulose esters, polycarbonates, polyarylate, polysulfone (including polyethersulfone), polyethylene terephthalate, polyethylene naphthalate and other polyesters, polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, Cellulose acetate propionate, cellulose acetate butyrate, polyvinylidene chloride, polyvinyl alcohol, ethylene-vinyl alcohol copolymer, syndiotactic polystyrene, polycarbonate, polynorbornene, polymethylpentene, polyether ketone, polyether ketone imide, polyamide Fluorine resin, nylon, polymethyl methacrylate, or acrylic resin It can gel. Among these, an acrylic resin is preferable. Further, the resin coat layer may contain a curing agent such as 2.4-tolylene diisocyanate. When the curing agent is included, the resin coat layer includes a cured product of the binder.

As a corrosion inhibitor, it is preferable to have an adsorptive group with respect to the metal which comprises a light reflection layer. Here, “corrosion” refers to a phenomenon in which a metal is chemically or electrochemically eroded or deteriorated in material by an environmental substance surrounding it (see JIS Z0103: 2004). The optimum content of the corrosion inhibitor varies depending on the compound used, but is generally preferably in the range of 0.1 to 1.0 g / m ² .

Examples of the corrosion inhibitor having an adsorptive group for metals include amines and derivatives thereof, compounds having a pyrrole ring, compounds having a triazole ring such as benzotriazole, compounds having a pyrazole ring, compounds having a thiazole ring, and imidazole rings. It is preferable to be selected from at least one of a compound having an indazole ring, a compound having an indazole ring, a copper chelate compound, a thiourea, a compound having a mercapto group, a naphthalene compound, or a mixture of two or more thereof. In compounds such as benzotriazole, the ultraviolet absorber may also serve as a corrosion inhibitor. It is also possible to use a silicone-modified resin. More specifically, the corrosion inhibitors described in paragraphs “0063” to “0072” of JP2012-232538A can be used.

[Gas barrier layer]
A gas barrier layer may be provided on the light incident side of the silver reflective layer. The gas barrier layer is intended to prevent deterioration of the humidity, especially the deterioration of the resin base material and each component layer supported by the resin base material due to high humidity, but it has special functions and applications. As long as it has the function of preventing deterioration, a gas barrier layer of various modes can be provided.

The moisture-proof barrier layer, 40 ° C., the water vapor permeability at 90% RH, is preferably not more than 1g ^/ m 2 · day, more preferably at most 0.5g ^/ m 2 · day, 0 More preferably, it is ² g / m ² · day or less. In addition, the oxygen permeability of the gas barrier layer is preferably 0.6 ml / m ² / day / atm or less under the conditions of a measurement temperature of 23 ° C. and 90% RH.

Examples of the method for forming the gas barrier layer include a method of forming an inorganic oxide by a method such as a vacuum deposition method, a sputtering method, an ion beam assist method, a chemical vapor deposition method, etc., but a precursor of an inorganic oxide by a sol-gel method. A method of forming an inorganic oxide film by applying a heat treatment and / or ultraviolet irradiation treatment to the coating film after coating the body is also preferably used.

The inorganic oxide is formed by local heating from a sol using an organometallic compound as a raw material. For example, oxides of elements such as silicon, aluminum, zirconium, titanium, tantalum, zinc, barium, indium, tin, and niobium contained in the organometallic compound, such as silicon oxide, aluminum oxide, zirconium oxide, etc. is there. Of these, silicon oxide is preferred.

As a method for forming the inorganic oxide, it is preferable to use a so-called sol-gel method or a polysilazane method. The sol-gel method is a method of forming an inorganic oxide from an organometallic compound that is a precursor of an inorganic oxide, and the polysilazane method is a method of forming an inorganic oxide from a polysilazane that is a precursor of an inorganic oxide. For the compounds and details used in the sol-gel method, the compounds and methods described in paragraphs “0174” to “0191” of JP2012-232538A can be appropriately employed.

[Anchor layer]
The anchor layer is made of a resin, and is a layer provided for closely attaching the resin base material and the light reflection layer, or the support base material (resin film) of the light reflection layer and the light reflection layer. Therefore, the anchor layer has an adhesion property for closely adhering the resin base material (support base material) and the light reflection layer, heat resistance that can withstand heat when the light reflection layer is formed by a vacuum deposition method, and the light reflection layer. It is preferable to have smoothness to bring out the high reflection performance inherent in the.

The resin used for the anchor layer is not particularly limited as long as it satisfies the above conditions of adhesion, heat resistance, and smoothness. For example, polyester resin, polyurethane resin, acrylic resin, melamine resin, epoxy resin, Polyamide resin, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer resin, etc. can be used alone or in combination. From the viewpoint of weather resistance, a mixed resin of a polyester resin and a melamine resin or a mixed resin of a polyester resin and a urethane resin is preferable, and a thermosetting resin in which a curing agent such as isocyanate is further mixed is more preferable. When a hardening | curing agent is mixed, an anchor layer becomes a form containing the hardened | cured material of the said thermosetting resin.

The thickness of the anchor layer is preferably 0.01 to 3 μm, more preferably 0.1 to 2 μm. By satisfying this range, the unevenness of the resin substrate surface can be covered while maintaining the adhesion, smoothness can be improved, and the anchor layer can be sufficiently cured, resulting in the reflectivity of the film mirror. Can be increased.

Further, the anchor layer can contain the corrosion inhibitor described in the above section [Resin coat layer].

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

[Adhesive layer]
The adhesive layer of a film mirror is a layer for attaching a film mirror to a support by the adhesive layer to form a solar power generation reflective device. The film mirror may have a release layer on the side opposite to the light incident side of the adhesive layer. When a film mirror has a peeling layer, after peeling a peeling layer from an adhesion layer, a film mirror can be affixed on a support body through an adhesion layer.

The adhesive layer is not particularly limited, and for example, any of a dry laminate agent, a wet laminate agent, an adhesive agent, a heat seal agent, a hot melt agent, and the like is used. Examples of the adhesive include polyester resin, polyurethane resin, polyvinyl acetate resin, acrylic resin, and nitrile rubber. 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 100 μm from the viewpoints of the pressure-sensitive adhesive effect, the drying speed, and the like.

[Peeling layer]
The film mirror of the present invention may have a release layer on the side opposite to the light incident side of the adhesive layer. For example, when a film mirror is shipped, it is shipped with the release layer attached to the adhesive layer, the film mirror having the adhesive layer is peeled off from the release layer, and is bonded to another substrate to form a solar reflective mirror. be able to.

The release layer is not particularly limited as long as it can provide protection of the light reflecting layer. For example, an acrylic film or sheet, a polycarbonate film or sheet, a polyarylate film or sheet, a polyethylene naphthalate film or sheet, a polyethylene terephthalate film or sheet , Plastic film or sheet such as fluororesin film, or resin film or sheet kneaded with titanium oxide, silica, aluminum powder, copper powder, etc., coating the resin kneaded with these, or depositing metal such as aluminum on metal A resin film or sheet that has been subjected to surface treatment is used.

The thickness of the release layer is not particularly limited, but is usually preferably in the range of 12 to 250 μm.

In addition, it may be bonded after providing a recess or projection before bonding these release layers to the film mirror, or may be molded to have a recess or projection after bonding, You may simultaneously shape | mold so that it may have a recessed part and a convex part.

[Reflector for solar thermal power generation]
The solar power generation reflecting device of the present invention has the film mirror of the present invention and a self-supporting support, and the film mirror is bonded to the support through an adhesive layer. That is, this invention also provides the solar power generation reflective apparatus which has the film mirror of this invention, and a support body.

The self-supporting support preferably has one of the following configurations A and B.

A: It has a pair of metal flat plates and an intermediate layer provided between the metal flat plates, and the intermediate layer is a layer having a hollow structure or a layer made of a resin material.

B: A resin material layer having a hollow structure.

In the case of “self-supporting support”, “self-supporting” means supporting the opposite edge portions when cut to a size used as a support for a solar power generation reflector. This means that the support body is rigid enough to carry the support. The support body of the solar power generation reflection device has self-supporting properties, so that it is easy to handle when installing the solar power generation reflection device, and the holding member for holding the solar power generation reflection device has a simple configuration. Therefore, it is possible to reduce the weight of the reflection device, and it is possible to suppress power consumption during solar tracking.

As in the configuration A, the self-supporting support is composed of a pair of metal flat plates and an intermediate layer provided between the metal flat plates, and the intermediate layer is formed of a layer having a hollow structure or a resin material. By having a layer having a high flatness due to a metal flat plate. At the same time, the intermediate layer is a layer having a hollow structure or a layer made of a resin material, so that the weight of the support can be significantly reduced compared to the case where the support is made of only a metal flat plate. In addition, since the rigidity can be increased by the relatively lightweight intermediate layer, it is possible to provide a lightweight and self-supporting support. Even when a layer made of a resin material is used as the intermediate layer, it is possible to further reduce the weight by using a resin material layer having a hollow structure.

In addition, when the intermediate layer has a hollow structure, the intermediate layer functions as a heat insulating material, so that the temperature change of the metal flat plate on the back side is prevented from being transmitted to the film mirror, preventing condensation and deterioration due to heat. Can be suppressed.

As the metal flat plate forming the surface layer of the configuration A, steel plate, copper plate, aluminum plate, aluminum plated steel plate, aluminum alloy plated steel plate, copper plated steel plate, tin plated steel plate, chrome plated steel plate, stainless steel plate, etc. A high metal material can be preferably 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.

When the intermediate layer of the configuration A has a hollow structure, a material such as a metal, an inorganic material (glass or the like), or a resin can be used. As the hollow structure, a cellular structure made of foamed resin, a three-dimensional structure (honeycomb structure or the like) having a wall surface made of metal, an inorganic material or a resin material, a resin material to which hollow fine particles are added, or the like can be used. The cellular structure of the foamed resin refers to a gas that is finely dispersed in the resin material and formed into a foamed or porous shape. As the material, a known foamed resin material can be used, but a polyolefin resin, Polyurethane, polyethylene, polystyrene and the like are preferably used. The honeycomb structure represents a general three-dimensional structure composed of a plurality of small spaces surrounded by side walls. When the hollow structure is a three-dimensional structure having a wall surface made of a resin material, the resin material constituting the wall surface is a homopolymer or copolymer of olefins such as ethylene, propylene, butene, isoprene pentene, and methylpentene. Polyolefin (eg, polypropylene, high density polyethylene), polyamide, polystyrene, polyvinyl chloride, polyacrylonitrile, acrylic derivatives such as ethylene-ethyl acrylate copolymer, polycarbonate, vinyl acetate copolymer such as ethylene-vinyl acetate copolymer Polymers, ionomers, terpolymers such as ethylene-propylene-dienes, and thermoplastic resins such as ABS resins, polyolefin oxides, and polyacetals are preferably used. In addition, these may be used individually by 1 type, or may mix and use 2 or more types. Among the thermoplastic resins, polyolefin resins or resins mainly composed of polyolefin resins are preferable, and polypropylene resins or resins mainly composed of polypropylene resins are more preferable because of excellent balance between mechanical strength and moldability. The resin material may contain an additive. Examples of the additive include silica, mica, talc, calcium carbonate, glass fiber, carbon fiber, and other inorganic fillers, plasticizers, stabilizers, colorants, charging agents. An inhibitor, a flame retardant, a foaming agent, etc. are mentioned.

In addition, the intermediate layer can be a layer made of a resin plate. In this case, the resin material constituting the intermediate layer is preferably the same as the material constituting the support for the film mirror described above. Can do.

The intermediate layer need not be provided in all regions of the substrate, and may be provided in a part of the region as long as the flatness of the metal flat plate and the self-supporting property as the support can be ensured. When the intermediate layer has the above-described three-dimensional structure, it is preferable to provide the three-dimensional structure in a region of about 90 to 95% with respect to the area of the metal flat plate. It is preferable to provide it.

As in the above configuration B, the self-supporting support may be a layer made of a resin material having a hollow structure. When the support is made of a resin-only layer, the thickness required to obtain rigidity sufficient to provide self-supporting properties increases, and as a result, the mass of the support becomes heavy. By providing the weight, it is possible to reduce the weight while providing a self-supporting property. In the case of a layer made of a resin material having a hollow structure, a resin sheet having a smooth surface is provided as a surface layer, and the resin material having a hollow structure is used as an intermediate layer from the viewpoint of increasing the regular reflectance of the film mirror. preferable. As the material of this resin sheet, the same material as that constituting the resin substrate of the above-mentioned film mirror can be preferably used, and as the resin material constituting the hollow structure, the above-mentioned foamed material or three-dimensional structure can be used. The same resin material as that used can be preferably used.

[Holding member]
The solar power generation reflecting device according to the present invention may have a holding member. The holding member preferably holds the film mirror and the support in a state where the sun can be tracked. Although there is no restriction | limiting in particular as a form of a holding member, For example, the form which hold | maintains several places with a rod-shaped holding member is preferable so that a film mirror and a support body can hold | maintain a desired shape. The holding member has a configuration for holding the film mirror and the support in a state where the sun can be tracked. However, when the sun is tracked, it may be driven manually, or a separate drive device may be provided to automatically track the sun. It is good also as a structure.

The effect of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. Further, in the examples, “part” or “%” is used, but “part by mass” or “% by mass” is expressed unless otherwise specified. Further, in the following operations, unless otherwise specified, operations and physical properties are measured under the conditions of room temperature (20 to 25 ° C.) / Relative humidity 40 to 50% RH.

Example 1
A biaxially stretched polyester film (polyethylene terephthalate film (PET), thickness 25 μm) was used as the resin substrate. As a coating liquid for forming a hard coat adjacent layer, polymethyl methacrylate (PMMA) resin (EMB457, manufactured by Mitsubishi Rayon Co., Ltd.), acrylic rubber (Delpet SRB215, manufactured by Asahi Kasei Chemicals Corporation), and 1,6-hexamethylene diisocyanate As a particle for adjusting the Young's modulus so that the solid content ratio is 17: 3: 2 (mass ratio), “Nanoamand” which is nanodiamond made by Nanocarbon Laboratory Co., Ltd. is applied to PMMA resin. 20% by mass was added, and the above components were mixed in methyl ethyl ketone so that the concentration of the entire solid content was 22% by mass. The obtained coating solution is coated on one surface of the PET film by a bar coating method, and cured by drying at 80 ° C. for 1 minute, and has a thickness of 25 μm including a cured product of PMMA resin and acrylic rubber. A hard coat adjacent layer was formed.

Next, as a coating liquid for forming a hard coat layer, an acrylic silicone-based thermosetting resin Surcoat BP-16N (manufactured by Kinken Co., Ltd., 45 mass% methanol solution) is added with 1-propanol to a solid content of 30 mass%. A coating solution was prepared as described above. This coating solution is coated on the hard coat adjacent layer by the bar coating method, and is cured by drying at 80 ° C. for 1 minute, and a thickness of 3 μm including the cured product of the acrylic silicone thermosetting resin is applied. A hard coat layer was formed.

Next, a light reflecting layer made of aluminum having a thickness of 100 nm was formed on the opposite surface of the resin base material on which the hard coat adjacent layer was formed by a vacuum deposition method.

2-Mercaptobenzothiazole as an aluminum corrosion inhibitor is 10% by mass with respect to the above mixture of polyester resin and 2.4-tolylene diisocyanate mixed at a mass ratio of 10: 2. In addition, a coating solution for forming a corrosion prevention layer was prepared such that the solid content concentration in methyl ethyl ketone was 5% by mass. This coating solution is coated on the light reflecting layer opposite to the side where the resin substrate of the light reflecting layer is provided by the gravure coating method, and cured at 80 ° C. for 1 minute to perform a curing treatment. A corrosion prevention layer having a thickness of 3 μm including the cured product was formed.

Thus, a film mirror was obtained.

(Example 2)
A film mirror was produced in the same manner as in Example 1 except that the amount of nanodiamond added to the hard coat adjacent layer forming coating solution was changed to 10% by mass.

Example 3
The particles added to the coating liquid for forming the hard coat adjacent layer were changed to 10% by mass of silica particles (Fuji Silysia Chemical Co., Ltd., Silicia (registered trademark) 470) with respect to the PMMA resin. Except that 0.05% by mass of Megafac (registered trademark) RS-76E, a UV reaction type surface modifier manufactured by DIC Corporation, was added to the PMMA resin in the coating solution for formation, Example 1 A film mirror was produced in the same manner.

Example 4
A film mirror was produced in the same manner as in Example 3 except that the amount of addition of Megafac (registered trademark) RS-76E was changed to 0.1% by mass.

(Example 5)
Except that the particles added to the hard coat adjacent layer forming coating solution were changed to 8 mass% aluminum particles (Minaluco's atomized aluminum powder 350F) with respect to the PMMA resin, the same as in Example 4. A film mirror was prepared.

(Example 6)
Implementation was performed except that the amount of aluminum particles added in the hard coat adjacent layer forming coating solution was 10% by mass and the light reflecting layer was changed to a layer made of 100 nm thick silver formed by vacuum deposition. A film mirror was produced in the same manner as in Example 5.

(Comparative Example 1)
A film mirror was prepared in the same manner as in Example 1 except that the Young's modulus adjusting particles were not added to the hard coat adjacent layer forming coating solution.

(Comparative Example 2)
A film mirror was produced in the same manner as in Comparative Example 1, except that 0.075% by mass of Megafac (registered trademark) RS-76E was added to the hard coat adjacent layer forming coating solution with respect to the PMMA resin.

(Comparative Example 3)
A film mirror was produced in the same manner as in Comparative Example 2, except that the amount of MegaFac (registered trademark) RS-76E was changed to 0.1% by mass.

(Comparative Example 4)
The same as Comparative Example 2 except that 6% by mass of aluminum particles (manufactured by Minalco Co., Ltd., atomized aluminum powder 350F) as Young's modulus adjusting particles were added to the hard coat adjacent layer forming coating solution. Thus, a film mirror was produced.

[Evaluation]
The obtained film mirror was evaluated by the following dynamic friction coefficient measurement, initial reflectance measurement, and post-scratch reflectance measurement.

(Dynamic friction coefficient measurement)
A film mirror sample was cut into a size of 10 cm × 20 cm, and the dynamic friction coefficient of the hard coat layer was measured in accordance with JIS K7125: 1999.

(Initial reflectance measurement)
A film mirror sample was cut into a size of 5 cm × 5 cm, and adjusted using a spectrophotometer U-4100 (manufactured by Shimadzu Corporation) so that the incident angle was 5 ° with respect to the normal of the reflecting surface. The regular reflectance at a reflection angle of 5 ° was measured. Evaluation was carried out as an average reflectance of 250 nm to 2500 nm.

(Reflectance measurement after scratch)
A film mirror sample was cut into a size of 5 cm × 10 cm and a scratch test was performed. In the scratch test, a surface property measuring machine manufactured by Shinto Kagaku Co., Ltd., Tribo Station TYPE: 32, was used, and steel wool was reciprocated 10 times at a speed of 500 mm / min so that a load of 500 g / cm ² was applied. After the scratch test, the regular reflectance at a reflection angle of 5 ° was measured in the same manner as the initial reflectance measurement.

(Measurement of Young's modulus of the hard coat adjacent layer)
In order to measure the Young's modulus of the hard coat adjacent layer, a single film sample of the hard coat adjacent layer was cut into a 1 cm × 5 cm strip. This single membrane sample was subjected to a tensile test at a speed of 50 mm / min using a Tensilon universal material testing machine, RTF-2430, manufactured by A & D Co., Ltd., and the Young's modulus was obtained.

Table 1 shows the configurations and evaluation results of the film mirrors of Examples and Comparative Examples. The “Δ reflectance” in Table 1 indicates the difference between the reflectance after scratch and the initial reflectance. The closer to 0, the smaller the decrease in regular reflectance after surface scratching, and the better the scratch resistance. Expresses superiority.

As is apparent from Table 1 above, the film mirror of the present invention has little decrease in regular reflectance after surface scratching and is excellent in surface scratch resistance.

Note that this application is based on Japanese Patent Application No. 2014-17960 filed on January 31, 2014, the disclosure of which is incorporated by reference in its entirety.

Claims (6)

1. A resin substrate and a light reflecting layer;
   A hard coat layer located closest to the light incident side;
   A hard coat adjacent layer provided adjacent to the hard coat layer;
   Have
   The film mirror whose Young's modulus of the said hard-coat adjacent layer is 4.5 GPa or more.
2. The film mirror according to claim 1, wherein the Young's modulus of the hard coat adjacent layer is 20 GPa or less.
3. The film mirror according to claim 1 or 2, wherein the dynamic friction coefficient of the hard coat layer is 0.4 or less.
4. The film mirror according to claim 3, wherein a dynamic friction coefficient of the hard coat layer is 0.25 or less.
5. The film mirror according to any one of claims 1 to 4, wherein the light reflecting layer is made of silver.
6. A film mirror according to any one of claims 1 to 5;
   A support;
   A solar power generation reflecting device.

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