JP2014199292A - Film mirror and method of producing the same, and solar light reflecting plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film mirror that prevents decrease in reflectance and has excellent durability and a method of producing the same.SOLUTION: This film mirror has a resin base material, a resin intermediate layer, a reflection layer comprising metal, and a protective layer with a thickness of 30 μm or less, wherein the number of foreign materials with an outer diameter of 10 μm or more is 50/cmor less, in this order.

Description

  The present invention relates to a film mirror, a manufacturing method thereof, and a solar light reflector.

  In recent years, research on alternative energy alternatives to fossil fuels typified by oil, coal, and natural gas has been actively conducted. In particular, natural energy such as solar light, wind power, and geothermal heat has attracted attention as clean energy without concern about resource depletion and global warming. Among these, solar energy using sunlight is expected to be further developed as energy that can be stably supplied.

On the other hand, however, solar energy has a problem of low energy density. In order to solve this problem, in recent years, attempts have been made to collect sunlight using a huge reflector.
Until now, reflectors for concentrating sunlight have been installed outdoors and exposed to ultraviolet light contained in sunlight, heat caused by sunlight, wind and rain, dust, etc. Has been. However, although the glass-made reflecting mirror is excellent in weather resistance, there is a problem that there is room for improvement in handling property because it is heavy, easily broken, and lacks flexibility.

  In order to solve the above problem, it is considered to replace the glass reflector with a light and flexible resin reflector (film mirror). Film mirrors are difficult to impart weather resistance compared to glass reflectors, but they provide high weather resistance, such as providing a gas barrier layer with a metal oxide on the surface of the resin base and the metal reflective layer. A technique has been proposed (see, for example, Patent Document 1).

  On the other hand, apart from the above-mentioned technology for improving the weather resistance that is lowered due to the resin, it becomes a raw material for the pressure-sensitive adhesive layer in order to reduce appearance defects of the pressure-sensitive adhesive layer for bonding the reflective layer and the protective layer. It has been disclosed to remove foreign substances in an adhesive coating solution (see, for example, Patent Document 2).

  Moreover, in order to form a favorable reflective surface as a laser reflecting mirror, it is disclosed that a molten alloy is passed through a filter medium having a pore diameter of 10 μm or less (see, for example, Patent Document 3).

International Publication No. 2011/096151 Pamphlet JP 2012-229305 A JP 59-157235 A

  As described above, conventionally, the removal of foreign matters mixed in a coating solution or the like has been performed in various technical fields. However, in order to use resin materials in the field of film mirrors that are installed outdoors and are used in harsh environments that are constantly exposed to ultraviolet light, heat, wind and rain, sand dust, etc. caused by sunlight, minute defects due to the use of resin materials. As a matter of fact, a technology for preventing the migration of metals through the metal, and thus causing a significant decrease in durability (light reflectance) is not well established.

  In a film mirror, for example, foreign matters are mixed in the constituent layers, and for example, a protective layer (so-called overcoat layer) constituting the outermost layer has a locally thin portion, or foreign matters exist on the layer surface. As a result, the vicinity of the foreign matter is likely to deteriorate over time, and cracks and holes are easily formed in the constituent layers. Such a foreign matter or a defect such as a crack formed in the vicinity thereof becomes a starting point for accelerating corrosion of the internal metal in the film mirror. That is, the part where the foreign matter is present is inevitably thin and the layer is inevitably deteriorated with time, and the oxygen or sulfur gas or moisture in the atmosphere permeates with a very small amount due to the gap formed near the foreign matter. As a result, the durability is significantly reduced.

Further, when foreign matter is mixed in the reflective layer or the resin intermediate layer (so-called undercoat layer) disposed between the resin base material and the protective layer, the deterioration of the metal is further promoted. That is, since the reflective layer and the resin intermediate layer are generally thinner than the protective layer, the layer is more thin and easily torn due to the inclusion of foreign matter, and gas and moisture directly enter the reflective layer containing metal, Corrosion is likely to proceed.
In addition, when the uniform resin intermediate layer is not formed with foreign substances, the electric conduction of the layer is deteriorated, and a uniform reflective layer is obtained when a reflective layer is formed on the resin intermediate layer by, for example, plating. Therefore, the reflectivity will decrease.

  The present invention has been made in view of the above, and an object of the present invention is to provide a film mirror and a manufacturing method thereof, and a solar reflector, in which a decrease in reflectance is suppressed, and which is excellent in durability. The task is to do.

  In the present invention, when a relatively thin protective layer (so-called overcoat layer) is provided as the outermost layer of the film mirror, if a predetermined amount of foreign matter is mixed in the protective layer, the metal reflective layer inside the film mirror The knowledge of becoming the starting point of migration has been obtained and achieved based on such knowledge.

Specific means for achieving the above-described problems are as follows. That is,
The present invention according to the first aspect
<1> A resin base material, a resin intermediate layer, a reflective layer containing a metal, a protective layer having a thickness of 30 μm or less and an outer diameter of 10 μm or more of 50 / cm ² or less. It is the film mirror which it has in order.
<2> The protective layer is the film mirror of <1> in contact with the surface of the reflective layer.
<3> The film mirror according to <1> or <2>, wherein the thickness of the resin intermediate layer is 0.05 μm or more and 3 μm or less, and the number of foreign matters having an outer diameter of 1 μm or more is 50 pieces / mm ² or less. .
<4> The thickness of the reflective layer is 0.05 μm or more and 0.5 μm or less, and the number of foreign matters having an outer diameter of 1 μm or more is 50 pieces / mm ² or less. Any one of <1> to <3> It is a film mirror of description.
<5> The film mirror according to any one of <1> to <4>, wherein the metal contained in the reflective layer is silver.
<6> The film interlayer according to any one of <1> to <5>, wherein the resin intermediate layer is a plating undercoat polymer layer containing metal particles.
<7> The film mirror according to any one of <1> to <6>, which is used for collecting sunlight.

Next, the present invention according to the second aspect
<8> A solar reflective plate including the film mirror according to any one of <1> to <7> and a support material.
Next, the present invention according to the third aspect is
<9> A first filtration step of filtering the protective layer-forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 10 μm or less; A protective layer forming step of forming a protective layer by applying an intermediate layer and a reflective layer containing a metal in this order on the reflective layer having a multilayer structure.
<10> The second filtration step of filtering the reflective layer forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less, and the reflective layer forming composition after filtration constitute the multilayer structure. The method for producing a film mirror according to <9>, further comprising: a reflective layer forming step of forming a reflective layer containing the metal by being applied on the resin intermediate layer.
<11> The reflective layer forming step is a method for producing a film mirror according to <10>, in which a silver reflective layer is formed as a reflective layer containing the metal by a plating method using a silver plating solution.
<12> A third filtration step of filtering the resin intermediate layer forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less, and the filtered resin intermediate layer forming composition, the multilayer structure The process for producing a film mirror according to any one of <9> to <11>, further comprising: a resin intermediate layer forming step of forming the resin intermediate layer by applying the resin on the resin substrate. Is the method.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of a reflectance is suppressed and the film mirror excellent in durability, its manufacturing method, and a sunlight reflecting plate are provided.

  Hereinafter, the film mirror of the present invention and the manufacturing method thereof will be described in detail, and the solar reflective plate of the present invention will also be described through the description.

<Film mirror and manufacturing method thereof>
The film mirror of the present invention has a resin intermediate layer, a reflective layer containing metal (hereinafter also referred to as “metal reflective layer”), a thickness of 30 μm or less, and an outer diameter of 10 μm or more on a resin base material. A protective layer having a number of foreign matters of 50 / cm ² or less is provided in this order.

Conventionally, when a layer is formed on a base material, it is generally performed that the liquid is filtered in advance before forming the layer so that a large amount of unnecessary particulate matter is not mixed in the formed layer. . However, this filtration treatment is usually performed from the viewpoint of uniformity of thickness, smoothness of the surface, etc., because there is concern about the occurrence of film surface defects such as bulges on the surface of the layer and undulations. . Therefore, even when the thickness of the layer is relatively thick, filtration is performed as a normal process, and the filter in that case is only selected with a pore size that can remove coarse particulate matter. Is the actual situation.
However, for products used in harsh environments such as film mirrors that are installed outdoors and are constantly exposed to ultraviolet light, heat, wind, rain, dust, etc., caused by sunlight, in the layer or the surface of the layer If there is a cause that causes migration, the durability tends to be significantly reduced starting from the cause.
Therefore, in the present invention, it is formed on a thin film having a thickness of 30 μm or less in order to maintain the transmittance of incident light even though it is located on the outermost layer of the film mirror and is easily affected by the severe installation environment. In the protective layer to be formed, the number of foreign matters having an outer diameter of 10 μm or more is set to a very small range of 50 pieces / cm ² or less. As a result, the part where the foreign substance is mixed is partially thinned to prevent a defect such as a crack or a hole from being locally generated over time, and a gas such as oxygen or moisture permeates into the layer starting from the foreign substance. As a result, deterioration of the reflective layer is suppressed. As a result, a decrease in light reflectance in the film mirror is suppressed, and the durability is excellent.

  The film mirror of the present invention has a multi-layer structure in which at least a resin base material, a resin intermediate layer, a metal reflective layer, and a protective layer are provided in this order. If necessary, other layers are additionally provided. It may have a structured structure.

-Protective layer-
The film mirror of this invention is arrange | positioned as the upper layer of the below-mentioned metal reflective layer on the side into which sunlight injects, and is provided with the protective layer as an outermost layer which is easy to be influenced by an installation environment. The protective layer in the present invention is formed with a thickness of 30 μm or less, and the number of foreign matters having an outer diameter of 10 μm or more contained in the layer is 50 / cm ² or less.
A protective layer bears the function which prevents deterioration and breakage of a film mirror by sunlight, rainwater, sand dust, etc., and aims at stabilization of specularity.

The thickness of the protective layer in the present invention is 30 μm or less. A thickness of 30 μm or less means that the protective layer is a thin layer. In the case of a thin layer having a thickness of 30 μm or less, there is a great influence due to mixing of foreign matters having an outer diameter of 10 μm or more. In other words, the portion where the foreign matter exists in the layer is reduced in thickness by reducing the film component for the volume of the foreign matter, so that the weather resistance that the protective layer should originally have cannot be obtained, and the layer deteriorates in the vicinity of the foreign matter, and as a result It is easy to make a starting point for gas and moisture to penetrate into the layer. Therefore, when the thickness is 30 μm or less, the effect of reducing the number of foreign matters having an outer diameter of 10 μm or more to 50 pieces / cm ² or less is great.

The thickness of the protective layer is preferably in the range of 0.5 μm to 30 μm, more preferably in the range of 1 μm to 20 μm, and still more preferably 1 μm to 15 μm.
When the thickness is 0.5 μm or more, the function as the protective layer can be obtained more favorably, and it is more advantageous in that the durability of the film mirror is ensured.

In the protective layer according to the present invention, the number of foreign matters having an outer diameter of 10 μm or more contained in the layer is 50 / cm ² or less. In light of the thickness of the protective layer, if the number of foreign matters having an outer diameter of 10 μm or more exceeds 50 / cm ² , the function as the protective layer cannot be maintained for a long time, and the durability of the film mirror is lowered. Specifically, the presence of a relatively large foreign substance having an outer diameter of 10 μm or more in excess of 50 / cm ² leads to local deterioration because the thickness of the protective film cannot be kept uniform. It is easy to make a crack, a hole or the like in the vicinity of the foreign substance, and this becomes a starting point for penetration of gas and moisture in the environment into the film.
The smaller the number of foreign matters that are mixed, the better, but it is difficult to contain no foreign matters. From the viewpoint of ensuring the durability required as a film mirror, it is preferably 30 pieces / cm ² or less per unit area. Furthermore, it is 15 pieces / cm ² or less.

  A foreign substance is an irregular-shaped particulate matter, and refers to a thing mixed with dust (including various forms such as granular and fibrous forms) scattered mainly in the atmosphere during the manufacturing process.

The outer diameter of the foreign material means the length (maximum length) of the longest part in appearance. The outer diameter is a value obtained by measuring the foreign matter observed by enlarging the protective layer with a microscope.
Further, the number of foreign matters is obtained as an average value of measured values in a plurality of regions after measuring the number of foreign matters (number / mm ² ) having an outer diameter of 10 μm or more existing in a plurality of regions having a predetermined area.

In the protective layer in the present invention, examples of the method for setting the number of foreign matters having an outer diameter of 10 μm or more to 50 / cm ² or less include the following methods. That is,
(1) The protective layer forming composition (for example, coating solution) is filtered with a filter.
(2) One of the steps for forming a protective layer, specifically, a step for preparing a protective layer forming composition, a step for forming a protective layer by applying the protective layer forming composition, etc. Part processes or a series of processes are performed in a clean environment.
Examples of the clean environment include an atmosphere cleaned to a predetermined cleanliness level, such as a clean room, a clean booth, or a clean bench. A clean environment can be formed, for example, by circulating the internal atmosphere with a cleaning filter or the like. Moreover, it is preferable that the cleanliness level of suspended fine particles or the like in a clean environment is limited to a high cleanliness of class 10,000 or less.
The above methods (1) to (2) may be carried out by selecting either one according to necessity, such as the purpose and desired amount of foreign matter, or both methods (1) and (2) are performed. May be.

The material which comprises the protective layer in this invention is not restrict | limited in particular, For example, resin, glass, ceramics etc. are mentioned. Among these, a resin is preferable in terms of excellent flexibility.
The resin material used for forming the protective layer is a resin capable of forming a film or layer, and the strength or durability of the formed film or layer, air and moisture blocking properties, and further adjacent to the protective layer It is preferable to select a resin that can achieve transparency, in particular, high transparency to light having a wavelength required by the film mirror, in addition to adhesion to a layer to be etched, such as a corrosion prevention layer.

Examples of the resin include cellulose ester resins (for example, cellulose diacetate resin, cellulose triacetate resin, cellulose acetate propionate resin, cellulose acetate butyrate resin), carbonate resins, arylate resins, sulfones (also polyether sulfone). Resin), ester resin (eg, polyethylene terephthalate, polyethylene naphthalate, etc.), vinyl resin (eg, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl alcohol resin, ethylene vinyl acetate resin), norbornene resin, polymethylpentene Resin, amide resin, fluorine resin, acrylic resin (eg, polymethyl methacrylate (PMMA)), olefin resin (eg, polyethylene, polypropylene) Emissions, ethylene-acrylate copolymer, ethylene-acrylic acid copolymer), may be mentioned polyurethane resins, and the like.
Of these, carbonate resins, ester resins, norbornene resins, acrylic resins, fluorine resins (for example, polyvinylidene fluoride (PVDF)), olefin resins, urethane resins, and the like are preferable. Specific preferred examples are polyvinylidene fluoride and polymethyl methacrylate, and PMMA is more preferred from the viewpoint of light transmittance.

  The protective layer may contain additives such as an ultraviolet absorber, a photopolymerization initiator, an antistatic agent, a coating aid (leveling agent), an antioxidant, and an antifoaming agent.

  The protective layer is preferably provided adjacent to the surface on the incident light side of the metal reflective layer described later. When the foreign material in the protective layer is the starting point and gas or moisture enters the film to cause deterioration, and when the metal reflective layer is adjacent to the protective layer, the metal in the metal reflective layer is further deteriorated. It tends to be accompanied by a decrease in light reflectivity of the metal reflection layer. That is, the effect of the present invention is more effectively exhibited when the protective layer is disposed adjacent to the metal reflective layer.

-Metal reflective layer-
The film mirror of this invention is equipped with the reflection layer (metal reflection layer) containing a metal as a lower layer (layer by which the resin base material is arrange | positioned) of a protective layer. The metal reflection layer reflects the light incident through the protective layer.

The material for forming the metal reflection layer is not particularly limited as long as it is a metal material that reflects visible light and infrared light, and examples thereof include silver and aluminum. From the viewpoint of light reflection performance, silver or an alloy containing silver is preferable. Silver or an alloy containing silver can increase the reflectance in the visible light region of the film mirror and reduce the dependency of the reflectance on the incident angle. The visible light region means a wavelength region of 400 nm to 700 nm.
Here, the incident angle means an angle with respect to a line perpendicular to the film surface.

  As an alloy containing silver, other metals such as gold, palladium, copper, nickel, iron, gallium, and indium are used as long as they do not affect the reflective properties of the reflective layer from the viewpoint of further improving the durability of the reflective layer. One or more metals selected from the group consisting of titanium, and bismuth may be included, and it is also a preferred embodiment to use an alloy made of silver and other metals. As the silver alloy, an alloy of silver and one or more metals selected from gold, copper, nickel, iron, and palladium is particularly preferable from the viewpoints of moist heat resistance, reflectance, and the like.

  For example, when the metal reflective layer is a film made of a silver alloy, the silver content is 90 atomic% to 99.8 atomic% in the total (100 atomic%) of silver and other metals in the metallic reflective layer. preferable. Further, the content of other metals is preferably 0.2 atomic% to 10 atomic% from the viewpoint of durability.

The arithmetic surface roughness (Ra) on the light incident side of the metal reflective layer is preferably 20 nm or less, more preferably 10 nm or less, and even more preferably 5 nm or less. By setting it within this range, the reflectivity of the film mirror is further improved and light can be collected efficiently.
In the present invention, the arithmetic surface roughness (Ra) is defined in JIS B 0601-2001.

There is no restriction | limiting in particular as a formation method of a metal reflective layer, You may employ | adopt either a wet method or a dry method.
Examples of the wet method include an electroplating method. Examples of the dry method include a vacuum deposition method, a sputtering method, and an ion plating method.

Hereinafter, a case where the metal reflective layer is formed by a plating method will be described.
Compared with vapor deposition methods such as vacuum deposition and sputtering, sol-gel methods, and solvent coating methods, the plating method enables film formation corresponding to the surface shape of the film to be formed. It is preferable because the metal reflective layer can be formed with a thickness.
As the plating method, a conventionally known method can be used. In addition, as a metal used for plating of this process, copper, chromium, lead, nickel, gold | metal | money, silver, tin, zinc etc. are mentioned, From the viewpoint of the initial reflectivity of a film mirror, silver is preferable.

  Examples of metal compounds used for plating include silver nitrate, silver acetate, silver sulfate, silver carbonate, silver methanesulfonate, silver ammonia, silver cyanide, silver thiocyanate, silver chloride, silver bromide, silver chromate, and chloranil. Examples thereof include silver compounds such as silver oxide, silver salicylate, silver diethyldithiocarbamate, silver diethyldithiocarbamate, and silver p-toluenesulfonate. Among these, silver methanesulfonate is preferable from the viewpoint of environmental impact and smoothness.

  As the metal used for the plating in this step, it is preferable to simultaneously use silver and one or more metals selected from the group consisting of gold, palladium, tin, gallium, indium, copper, titanium, and bismuth. It is preferable from the viewpoint of improving durability. Among them, it is particularly preferable to use silver and gold at the same time from the viewpoints of heat and humidity resistance, reflectance, and the like.

  In that case, in the total (100 atomic%) of silver and other metals in the metal reflection layer, the silver content is 90 atomic% to 99.8 atomic%, and the other metal content is 0.2. Plating from atomic% to 10 atomic% is preferable from the viewpoint of durability.

In the present invention, from the viewpoint of adhesion between the resin substrate and the metal reflective layer, a resin intermediate layer may be provided on the resin substrate, and the resin intermediate layer is formed from an easy-adhesion layer and a plating undercoat polymer layer. It may be composed of one or two selected layers. In addition, the plating undercoat polymer layer may contain reduced metal particles. When the plating undercoat polymer layer has a function as an electrode, a metal reflective layer is formed by electroplating the plating undercoat polymer layer. can do.

In addition, between the plating undercoat polymer layer and the metal reflective layer, for example, a metal layer containing another metal such as copper, nickel, chromium, iron, or the like may be provided as a base metal layer.
Moreover, the film thickness of the metal reflective layer obtained by electroplating can be controlled by adjusting the metal concentration or current density contained in the plating bath. By adding a base metal layer having an appropriate thickness, it is possible to improve reflectance and reduce pinholes by smoothing the surface.

  Moreover, in this invention, you may form a metal reflective layer by performing dry plating, such as vacuum evaporation, using the plating undercoat polymer layer containing the reduced metal particle. According to this method, since the surface of the plating undercoat polymer layer is covered with metal, it is possible to form a metal reflective layer that has better adhesion than normal vapor deposition and is strong against heat.

After plating, the metal reflective layer may be treated with a strong acid, strong alkali, or the like in order to improve the reflection performance and durability of the metal reflective layer. Further, an inorganic film or a metal oxide film may be formed on the metal surface. Moreover, you may further provide the discoloration prevention agent layer containing a discoloration prevention agent.
The anti-discoloring agent layer functions to prevent discoloration of the metal reflective layer. Examples of the discoloration preventing agent include thioether-based, thiol-based, Ni-based organic compound-based, benzotriazole-based, imidazole-based, oxazole-based, tetrazaindene-based, pyrimidine-based, and thiadiazole-based discoloration preventing agents.
The anti-discoloring agent layer is broadly classified, and those having an adsorbing group that adsorbs metals and antioxidants are preferably used.

  In the present invention, the metal reflective layer may be formed by a dry method such as vacuum deposition using a plating undercoat polymer layer containing reduced metal particles. According to this method, since the surface of the plating undercoat polymer layer is covered with metal, it is possible to form a metal reflective layer that has better adhesion than normal vapor deposition and is strong against heat.

The thickness of the metal reflective layer is preferably in the range of 0.05 μm to 2.0 μm, and preferably in the range of 0.05 μm to 0.5 μm. When the thickness is in this range, the effect of suppressing the decrease in the reflectance of the metal reflective layer is great, and the durability is more effectively improved. Further, it is also preferable in that a reflection film is formed without pinholes and that there is no unevenness that scatters light on the surface of the metal reflection layer.
A more preferable thickness of the metal reflective layer is 0.07 μm or more and 0.2 μm or less.

In the metal reflective layer in the present invention, the number of foreign matters having an outer diameter of 1 μm or more contained in the layer is preferably 50 / mm ² or less. When the number of foreign matters having an outer diameter of 1 μm or more is 50 / mm ² or less, the thickness of the protective film can be kept uniform, and cracks and holes are hardly formed in the vicinity of the foreign matter.
When the thickness of the metal reflective layer is within the above range, the influence of foreign matters having an outer diameter of 1 μm or more is large. In other words, the location where the foreign object exists in the metal reflective layer is reduced in thickness by reducing the film component for the volume of the foreign object, so that the weather resistance that the reflective layer should originally have cannot be maintained, and the layer deteriorates in the vicinity of the foreign object. As a result, it is easy to make a starting point for gas and moisture to penetrate into the layer. When the starting point is formed in the metal reflection layer, the metal in the metal reflection layer is directly oxidized or the like, so that the durability is more easily lowered. Therefore, not only the protective layer but also the metal reflective layer has a foreign matter having an outer diameter of 1 μm or more and the number of foreign matters is 50 pieces / mm ² or less, so that the effect of suppressing the decrease in the reflectivity of the reflective layer appears greatly, and the durability of the film mirror Can be increased more effectively.

The smaller the number of foreign matters mixed, the better, but it is difficult to contain no foreign matters. From the viewpoint of further improving the durability required as a film mirror, 30 pieces / mm ² or less per unit area is preferable. Furthermore, it is 15 pieces / mm ² or less.

In the metal reflective layer of the present invention, as a method for setting the number of foreign matters having an outer diameter of 1 μm or more to 50 pieces / mm ² or less, for example, a method for setting the number of foreign matters in the protective layer described above to 50 pieces / mm ² or less. A similar method can be applied. Details of the method are as described in the section of the protective layer.

-Resin intermediate layer-
The film mirror of this invention is equipped with the resin intermediate | middle layer between the above-mentioned reflection layer and the below-mentioned resin base material. By providing the resin intermediate layer, the adhesion between the resin base material and the reflective layer can be improved.

  Examples of the resin intermediate layer include an easy-adhesion layer for facilitating adhesion of metal, and a plating undercoat polymer layer useful when a metal reflective layer is formed by a plating method. It may be composed of two or more layers.

[Easily adhesive layer]
In this invention, you may provide an easily bonding layer in order to improve the adhesiveness of a resin base material and a metal reflective layer. In addition, when a plating undercoat polymer layer is provided on the easy adhesion layer, the adhesion between the resin substrate and the plating undercoat polymer layer is improved by the easy adhesion layer, and as a result, the adhesion between the resin substrate and the metal reflective layer is improved. Can be further improved.

The easy-adhesion layer preferably contains the same resin as that constituting the resin substrate or a resin having an affinity for the resin that constitutes the resin substrate, from the viewpoint of adhesion with the adjacent resin substrate.
The resin contained in the easy adhesion layer may be, for example, a thermosetting resin, a thermoplastic resin, or a mixture thereof. Examples of the thermosetting resin include epoxy resin, phenol resin, polyimide resin, polyester resin, bismaleimide resin, polyolefin resin, isocyanate resin, and the like. Examples of the thermoplastic resin include phenoxy resin, polyether sulfone, polysulfone, polyphenylene sulfone, polyphenylene sulfide, polyphenyl ether, polyether imide, and the like.
The thermoplastic resin and the thermosetting resin may be used alone or in combination of two or more. The combined use of two or more kinds of resins is performed for the purpose of expressing a more excellent effect by compensating for each defect.

When using a thermoplastic resin, it is preferable to use a crosslinking agent as needed. As a kind of the crosslinking agent, a crosslinking agent having a plurality of reactive groups that react with a functional group such as a carboxylic acid group, a hydroxyl group, an amino group, and a mercaptan group that the thermoplastic resin has is preferable. Preferred types of reactive groups include carbodiimide groups, oxazoline groups, isocyanate groups, epoxy groups, melamine and the like. Examples of the compound having a plurality of these reactive groups are commercially available products such as Carbodilite (manufactured by Nisshinbo Co., Ltd.), Epocross (manufactured by Nippon Shokubai Co., Ltd.), Denacol (manufactured by Nagase ChemteX Corporation), Becamine (North Japan DIC). And other crosslinking agents.
The addition amount of the crosslinking agent is preferably such that the functional group of the thermoplastic resin and the reactive group of the crosslinking agent are equivalent, but in order to obtain appropriate film properties, the addition amount of the crosslinking agent May be increased or decreased as appropriate.

When a plating undercoat polymer layer is provided on the easy adhesion layer, the easy adhesion layer includes functional groups and polymerizable groups that interact with metal particles or precursors thereof contained in the plating undercoat polymer layer described in detail below. It is preferable to contain an active species that generates an active site capable of interacting with the polymer compound. The easy adhesion layer is preferably, for example, a polymerization initiation layer containing a radical polymerization initiator or a polymerization initiation layer made of a resin having a functional group capable of initiating polymerization. More specifically, the easy adhesion layer is composed of a layer containing a polymer compound and a radical polymerization initiator, a layer containing a polymerizable compound and a radical polymerization initiator, or a resin having a functional group capable of initiating polymerization. A layer is preferred.
Examples of the layer made of a resin having a functional group capable of initiating polymerization include polyimide having a polymerization initiation site described in paragraphs [0018] to [0078] of JP-A-2005-307140 in the skeleton.

  Furthermore, when forming an easy-adhesion layer, a compound having a polymerizable double bond, specifically an acrylate compound or a methacrylate compound, may be used in order to promote crosslinking in the layer. It is preferable to use those. In addition, as a compound having a polymerizable double bond, a part of a thermosetting resin or a thermoplastic resin such as an epoxy resin, a phenol resin, a polyimide resin, a polyolefin resin, a fluorine resin, etc. Alternatively, a (meth) acrylated resin using acrylic acid or the like may be used.

  As long as the effects of the present invention are not impaired, the easy-adhesion layer in the present invention contains one or more various additives such as an adhesion-imparting agent, a silane coupling agent, an antioxidant, and an ultraviolet absorber as necessary. Two or more kinds may be added.

  In general, the thickness of the easy adhesion layer in the present invention is preferably in the range of 0.05 μm to 10 μm, more preferably in the range of 0.05 μm to 5 μm, and still more preferably in the range of 0.05 μm to 3 μm.

[Plating undercoat polymer layer]
The plating undercoat polymer layer in the present invention has at least a plating undercoat polymer and reduced metal particles. The plating undercoat polymer layer in the present invention is suitably used when the metal reflective layer is formed by a wet plating method.

  The plating undercoat polymer layer is formed by using a composition containing a metal precursor and a plating undercoat polymer described later, and forming a plating undercoat polymer layer containing the metal precursor on the resin substrate by a method such as coating, or A polymer layer containing a metal precursor is formed by forming a layer on a resin substrate using a composition containing a plating undercoat polymer, which will be described later, and then contacting the composition containing the metal precursor with this layer by a method such as immersion. It is preferable to form a plating undercoat polymer layer containing reduced metal particles by reducing the metal precursor contained in the plating undercoat polymer layer.

(Plating undercoat polymer)
The plating undercoat polymer has at least a functional group that interacts with the metal precursor (hereinafter, referred to as “interactive group” as appropriate), and from the viewpoint of water resistance and chemical resistance, it is polymerizable as necessary. It preferably has a group.
As the main skeleton of the plating undercoat polymer, acrylic polymers, polyethers, polyacrylamides, polyamides, polyimides, methacrylic polymers, polyesters, polyurethanes, ethylene acrylic acid copolymers, and the like are preferable, but acrylic polymers are more preferable.
The plating undercoat polymer may contain a constitutional unit other than a constitutional unit containing a polymerizable group and an interaction group depending on the purpose. When a plating undercoat composition is formed by including a structural unit other than the structural unit containing a polymerizable group and a structural unit containing an interactive group (hereinafter referred to as other structural unit as appropriate), water or It is excellent in solubility in an organic solvent, and a uniform plating undercoat layer can be formed.

As a preferable embodiment of the plating undercoat polymer, an acrylic polymer having an acidic group and a polymerizable group as an interactive group in the side chain can be mentioned.
Hereinafter, a polymerizable group, an interactive group, and characteristics of the plating undercoat polymer will be described in detail.

-Polymerizable group-
The polymerizable group of the plating undercoat polymer is polymer-based or polymer-undercoat layer (resin base material or easy adhesion layer or undercoat layer provided on the resin base material) by applying energy such as corona treatment or plasma treatment. Any functional group that can form a chemical bond with the. Examples of the polymerizable group include a radical polymerizable group and a cationic polymerizable group. Of these, a radical polymerizable group is preferable from the viewpoint of reactivity.
Examples of the radical polymerizable group include methacryloyl group, acryloyl group, itaconic acid ester group, crotonic acid ester group, isocrotonic acid ester group, maleic acid ester group, styryl group, vinyl group, acrylamide group and methacrylamide group. It is done. Among these, a methacryloyl group, an acryloyl group, a vinyl group, a styryl group, an acrylamide group, and a methacrylamide group are preferable, and from the viewpoint of radical polymerization reactivity and synthesis versatility, a methacryloyl group, an acryloyl group, an acrylamide group, and A methacrylamide group is preferable, and an acrylamide group and a methacrylamide group are more preferable from the viewpoint of alkali resistance.
Among them, various polymerizable groups introduced into the acrylic polymer include (meth) acryl groups such as (meth) acrylate groups or (meth) acrylamide groups, vinyl ester groups of carboxylic acids, vinyl ether groups, and allyl ether groups. A polymerizable group is preferred.

-Interactive group-
The interaction group of the plating undercoat polymer is a functional group that interacts with the metal precursor (for example, a coordination group, a metal ion adsorbing group, etc.), and can form an electrostatic interaction with the metal precursor. A functional group, or a nitrogen-containing functional group, a sulfur-containing functional group, an oxygen-containing functional group or the like that can form a coordination with a metal precursor can be used.
More specifically as an interactive group, amino group, amide group, imide group, urea group, triazole ring, imidazole group, pyridine group, pyrimidine group, pyrazine group, triazine group, piperidine group, piperazine group, pyrrolidine group, A nitrogen-containing functional group such as a pyrazole group, a group containing an alkylamine structure, a cyano group, a cyanate group (R—O—CN); an ether group, a hydroxyl group, a phenolic hydroxyl group, a carboxyl group, a carbonate group, a carbonyl group, an ester group, Oxygen-containing functional groups such as groups containing an N-oxide structure, groups containing an S-oxide structure, groups containing an N-hydroxy structure; thiophene groups, thiol groups, thiourea groups, sulfoxide groups, sulfonic acid groups, sulfonic acid ester structures Sulfur-containing functional groups such as groups containing phosphine groups; Phosphorus-containing functional groups such as those containing ester structure; chlorine, such as group containing a halogen atom such as bromine and the like, in a functional group capable of having a salt structure can also be used the salts thereof.
The interactive group may be a non-dissociative functional group or an ionic polar group, and these may be contained at the same time, but an ionic polar group is preferred.

  As the interactive group composed of an ionic polar group, among the above-mentioned interactive groups, the resin base of the plating undercoat polymer (in the case where the above easy-adhesion layer is formed on the resin base, the easy-adhesion layer From the viewpoint of adhesion to), carboxylic acid group, sulfonic acid group, phosphoric acid group, and boronic acid group are mentioned. Among them, it has moderate acidity (does not decompose other functional groups), Carboxylic acid groups are particularly preferred from the viewpoint that there are few concerns about influence, excellent compatibility with the plating layer, and easy availability of raw materials.

An ionic polar group such as a carboxylic acid group can be introduced into the plating undercoat polymer by copolymerizing a radical polymerizable compound having an acidic group.
Hereinafter, with regard to a preferable configuration of the plating undercoat polymer used in the present invention, as a polymer having an interactive group composed of a radical polymerizable group and a non-dissociable functional group, paragraph [0106] of JP2009-007540A is disclosed. ] To [0112] can be used. As the polymer having a radical polymerizable group and an interactive group composed of an ionic polar group, polymers described in paragraphs [0065] to [0070] of JP-A-2006-135271 can be used. Examples of the polymer having a radical polymerizable group, an interactive group composed of a non-dissociative functional group, and an interactive group composed of an ionic polar group include paragraphs [0010] to [0010] of [2010] -248464. [0128], polymers described in paragraphs [0030] to [0108] of JP 2010-84196 A and US Patent Application Publication No. 2010-080964 may be used.

  In addition, the metal precursor mentioned later may be provided after the plating undercoat polymer layer is formed, or may be contained in the composition for the plating undercoat polymer layer from the beginning. When the metal precursor is contained in the plating undercoat polymer layer forming composition, the content of the metal precursor is preferably 0.5% by mass to 100% by mass with respect to the total amount of the composition, and 1% by mass to 50%. The mass% is more preferable.

The plating undercoat polymer layer preferably contains a radical polymerization initiator such as a photopolymerization initiator or a thermal polymerization initiator in order to increase sensitivity to energy application. The radical polymerization initiator is not particularly limited, and generally known ones are used.
However, when energy is applied, the plating undercoat polymer can generate active sites that interact with the resin base material and the easy-adhesion layer, that is, when a polymer having a polymerization initiation site in the polymer skeleton described above is used. These radical polymerization initiators may not be added.

  The amount of the radical polymerization initiator to be contained in the plating undercoat polymer layer forming composition is selected according to the configuration of the plating undercoat polymer layer forming composition, but in general, the plating undercoat polymer layer forming composition. It is preferable that it is about 0.05 mass%-30 mass% in it, and it is more preferable that it is about 0.1 mass%-10.0 mass%.

  The plating undercoat polymer layer preferably contains reduced metal particles. Reduced metal particles contained in the plating undercoat polymer layer are obtained by applying a metal precursor to the plating undercoat polymer layer and reducing the metal precursor to form reduced metal particles. It is done. When the metal precursor is applied to the plating undercoat polymer layer, the metal precursor adheres to the interactive group by interaction.

A metal precursor will not be specifically limited if it functions as an electrode by changing to a metal by a reduction reaction. Moreover, as a metal precursor, what functions as an electrode of plating in formation of a metal reflective layer is mentioned preferably. Therefore, what functions as an electrode by reducing a metal precursor to a metal is preferable. Specifically, metal ions such as Au, Pt, Pd, Ag, Cu, Ni, Al, Fe, and Co are used. Metal ions that are metal precursors are contained in a composition containing a plating undercoat polymer (a composition for forming a plating undercoat polymer layer). After forming a layer on a resin substrate, a zero-valent metal is formed by a reduction reaction. Become particles. It is preferable that the metal ion which is a metal precursor is contained in the composition for forming a plating undercoat polymer layer as a metal salt.
As the metal ion, Ag ion, Cu ion, and Pd ion are preferable in terms of the type and number of functional groups capable of coordination, and catalytic ability.
As the Ag ions, those obtained by dissociating the silver compounds shown below can be suitably used. Specific examples of the silver compound include silver nitrate, silver acetate, silver sulfate, silver carbonate, silver cyanide, silver thiocyanate, silver chloride, silver bromide, silver chromate, silver chloranilate, silver salicylate, silver diethyldithiocarbamate, Examples thereof include silver diethyldithiocarbamate and silver p-toluenesulfonate. Among these, silver nitrate is preferable from the viewpoint of water solubility.
When Cu ions are used, those obtained by dissociating copper compounds as shown below can be suitably used. Specific examples of copper compounds include copper nitrate, copper acetate, copper sulfate, copper cyanide, copper thiocyanate, copper chloride, copper bromide, copper chromate, copper chloranilate, copper salicylate, copper diethyldithiocarbamate, diethyldithiol. Examples thereof include copper carbamate and copper p-toluenesulfonate. Among these, copper sulfate is preferable from the viewpoint of water solubility.

The metal precursor is preferably applied to the plating undercoat polymer layer as a dispersion or solution (metal precursor liquid).
As a method for the application, for example, a polymer layer containing a plating primer polymer is formed on a resin substrate using a composition containing a plating primer polymer, and then a metal precursor is included on the polymer layer containing the plating primer polymer. A method of applying a composition (dispersion or solution), or a method of immersing a resin substrate on which a polymer layer containing an undercoating undercoat polymer is formed in a composition (dispersion or solution) containing a metal precursor Is mentioned.
As described above, by bringing a dispersion or solution containing a metal precursor into contact with the polymer layer, an interaction group in the plating undercoat polymer can interact with an intermolecular force such as van der Waals force, or The metal precursor can be adsorbed by utilizing the interaction due to the coordinate bond by the lone electron pair.

From the viewpoint of sufficiently adsorbing the metal precursor, the concentration of the metal precursor in the dispersion or solution containing the metal precursor is preferably 0.001% by mass to 50% by mass, It is more preferable that it is mass%-30 mass%.
Water or an organic solvent is used as a solvent for the metal precursor dispersion and solution. By containing water or an organic solvent, the permeability of the metal precursor to the polymer layer is improved, and the metal precursor can be efficiently adsorbed to the interactive group.

When the dispersion is used for applying the metal precursor to the plating undercoat polymer layer, the particle diameter of the metal precursor is preferably 1 nm to 200 nm, more preferably 1 nm to 100 nm, and still more preferably 1 nm to 60 nm. By setting this particle size, the particle size of the reduced metal particles can be controlled to a desired size.
In addition, a particle diameter is an average primary particle diameter (volume conversion) here, and is read from the image of SEM (S-5200, Hitachi High-Tech Manufacturing & Service Co., Ltd.).

  Furthermore, you may make a dispersion liquid and a solution contain another additive according to the objective. Examples of other additives include swelling agents and surfactants.

Metal ions, which are metal precursors applied to the plating undercoat polymer layer, are reduced by a metal activation liquid (reducing liquid). The metal activation liquid is composed of a reducing agent that can reduce a metal precursor (mainly metal ions) to a zero-valent metal and a pH adjuster for activating the reducing agent.
The concentration of the reducing agent with respect to the entire metal activation liquid is preferably 0.05% by mass to 50% by mass, and more preferably 0.1% by mass to 30% by mass.
As the reducing agent, boron-based reducing agents such as sodium borohydride and dimethylamine borane, and reducing agents such as formaldehyde and hypophosphorous acid can be used. In particular, reduction with an aqueous alkaline solution containing formaldehyde is preferred.

The concentration of the pH adjuster with respect to the entire metal activation liquid is preferably 0.05% by mass to 10% by mass, and more preferably 0.1 to 5% by mass.
As the pH adjuster, acetic acid, hydrochloric acid, sulfuric acid, nitric acid, sodium hydrogen carbonate, aqueous ammonia, sodium hydroxide, potassium hydroxide and the like can be used.
The temperature during the reduction is preferably 10 ° C to 100 ° C, more preferably 20 ° C to 70 ° C.
These concentrations and temperature ranges are preferably within this range from the viewpoint of the particle diameter of the metal precursor, the surface roughness of the polymer layer, the conductivity (surface resistance value), and the deterioration of the reducing solution during reduction.

The particle diameter of the reduced metal particles contained in the plating undercoat polymer layer is preferably 1 nm to 200 nm, more preferably 1 nm to 100 nm, and still more preferably 1 nm to 60 nm from the viewpoint of reflection performance. By being in this range, the reflectance after plating becomes good.
The particle diameter is read from an SEM (S-5200 manufactured by Hitachi High-Tech Manufacturing & Service Co.) image.

The surface resistance value of the plating undercoat polymer layer containing the reduced metal particles is preferably 0.001Ω / □ or more and 100Ω / □ or less, and more preferably 0.03Ω / □ or more and 50Ω / □ or less. Within this range, the plated surface is formed uniformly and smoothly and the reflectance is good.
Further, the surface roughness (Ra) of the plating undercoat polymer layer containing the reduced metal particles is preferably 20 nm or less, and more preferably 10 nm or less, from the viewpoint of reflection performance.
The plating undercoat polymer layer containing the metal particles thus obtained is preferably used when the above-described metal reflective layer is formed by a plating method that is a wet method, and the plating undercoat polymer layer is used to form a plating method. The formed metal reflective layer is excellent in adhesion to the resin substrate and surface smoothness.

  The thickness of the resin intermediate layer is preferably 0.05 μm or more and 10 μm or less. When the thickness is in this range, the effect of further suppressing the decrease in the reflectance of the metal reflective layer is expected, and the durability can be more effectively enhanced. A more preferable thickness of the resin intermediate layer is 0.05 μm or more and 3 μm or less.

In the resin intermediate layer in the present invention, the number of foreign matters having an outer diameter of 1 μm or more contained in the layer is preferably 50 / mm ² or less. When the number of foreign matters having an outer diameter of 1 μm or more is 50 pieces / mm ² or less, the thickness of the resin intermediate layer can be kept uniform, and cracks and holes are hardly formed near the foreign matter.
When the thickness of the resin intermediate layer is within the above range, the influence of foreign matters having an outer diameter of 1 μm or more is large. In other words, where the foreign substance exists in the resin intermediate layer, the film component corresponding to the volume of the foreign substance is reduced and the thickness is reduced, so the weather resistance that the resin intermediate layer should originally have cannot be maintained, and the layer deteriorates in the vicinity of the foreign substance. As a result, it is easy to create a starting point for gas and moisture to penetrate into the layer. Therefore, not only in the protective layer but also in the resin intermediate layer, by reducing the number of foreign matters having an outer diameter of 1 μm or more to 50 pieces / mm ² or less, the effect of suppressing the reduction in the reflectivity of the reflective layer appears greatly, and consequently the durability of the film mirror It is more excellent in improving the property.

The number of foreign matters mixed in the resin intermediate layer is preferably as small as possible, but since it is difficult to contain no foreign matters at all, from the viewpoint of further enhancing the durability required as a film mirror, 30 pieces / mm ² or less per unit area is required. Further, it is preferably 15 pieces / mm ² or less.

In the resin intermediate layer in the present invention, as a method for setting the number of foreign matters having an outer diameter of 1 μm or more to 50 pieces / mm ² or less, for example, a method for setting the number of foreign matters in the protective layer described above to 50 pieces / mm ² or less. A similar method can be applied. Details of the method are as described in the section of the protective layer.

-Resin base material-
The film mirror of the present invention includes a resin base material.
There is no restriction | limiting in particular as resin which comprises a resin base material, According to the objective, it can select suitably. Examples of the resin include polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polycarbonate resins; acrylic resins such as polymethyl methacrylate; polyamide resins; polyimide resins; Examples thereof include vinyl resins; polyphenylene sulfide resins; polyether sulfone resins; polyethylene sulfide resins; polyphenylene ether resins; styrene resins; and cellulose resins such as cellulose acetate.
Of these, polyester resins, acrylic resins, and the like are preferable in that the transparency and weather resistance of the film mirror are good.

  There is no restriction | limiting in particular about the shape of a resin base material, What is necessary is just to select suitably according to the intended use aspect. The shape of the resin base material may be any of base materials having a surface shape such as a sheet shape (planar shape), a diffusion surface, a concave surface, and a convex surface.

  The thickness of the resin base material can be appropriately selected depending on the shape of the base material, the installation location of the film mirror, and the like. When the resin base material is planar, the lower limit value of the thickness of the resin base material is preferably 25 μm or more, more preferably 50 μm or more, and further preferably 100 μm or more from the viewpoint of mechanical strength. The upper limit of the thickness of the resin base material is not particularly limited, and may be defined from the viewpoints of flexibility, weight reduction, and handling during production, but is manufactured by roll-to-roll. In view of the above, 1000 μm or less is preferable, 600 μm or less is more preferable, and 500 μm or less is more preferable.

  By providing the resin base material, the film mirror achieves necessary strength and durability without being bonded to the metal base material, and also has flexibility.

~ Manufacturing method of film mirror ~
The method for producing a film mirror of the present invention includes a first filtration step of filtering a protective layer forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 10 μm or less, and a protective layer forming composition after filtration. And a protective layer forming step of forming a protective layer by providing the above on a reflective layer having a multilayer structure having a resin base material, a resin intermediate layer, and a reflective layer containing a metal in this order. The manufacturing method of the film mirror of this invention can further comprise the process of forming a reflection layer and a resin intermediate layer further as needed.

  As long as the film mirror which has a resin base material, a resin intermediate | middle layer, a reflection layer, and a protective layer in this order can be manufactured, what kind of thing may be sufficient as the order of a process. For example, a resin intermediate layer, a reflective layer, and a protective layer may be sequentially formed on a resin base material, or after a reflective layer and a resin intermediate layer are sequentially formed on a member having a protective layer, Materials may be bonded together.

Hereinafter, each process of the manufacturing method of the film mirror of this invention is demonstrated in detail.
[First filtration step]
In the first filtration step in the present invention, the protective layer forming composition is filtered using a filter medium having a filtration accuracy of 0.1 μm or more and 10 μm or less. By filtering the composition with a filter medium having a predetermined filtration accuracy, foreign matters in the liquid can be removed, and the number of foreign matters having an outer diameter of 10 μm or more can be reduced. Specifically, the number of foreign matters having an outer diameter of 10 μm or more per unit area of the protective layer formed by coating or the like can be adjusted to 50 / cm ² or less.
Filtration may be performed once or a plurality of times for a single coating solution.

As the filter medium, a commercially available product can be used, and a filtration filter having a pore size of 0.1 μm or more and 10 μm or less can be appropriately selected and used. Specific examples include syringe filters such as Myrelex-LG and LH manufactured by Merck Millipore, membrane filters such as hydrophilic durapore, omnipore, hydrophobic surapore, florinert and mitex, DISMIC-25HP, 13HP manufactured by Advantech, etc. Syringe Filters, Hydrophilic PTFE Type Membrane Filters, Pole Acrodisc PTFE Syringe Filters, TF (PTFE) Disc Filters, Depth Filters such as Profile II, Nexis NXA, Nexis NXT, and Pleated Depth Filters such as Profile Star And pleated filters such as HDCII and Polyfine II.
The filtration accuracy is preferably in the range of 0.1 to 5 μm from the viewpoint of further reducing the number of foreign matters having an outer diameter of 10 μm or more when the protective layer is formed.

In this specification, “filtration accuracy” is defined by rated filtration accuracy.
“Rated filtration accuracy” is the filtration accuracy obtained by the single pass-F2 test method, which is a unified standard created in accordance with ANSI (American National Standards Institute) standard (B93.31). The ratio is calculated as a beta value (β value), and the particle size X micron when βx = 5000 is used as the rated filtration accuracy.

In addition, in order to adjust the number of foreign matters in the protective layer to 50 pieces / cm ² or less, it is desirable that the first filtration step is performed in a clean environment. By carrying out in a clean environment, mixing of suspended fine particles in the atmosphere into the composition can be suppressed. Details of the clean environment method and cleanliness level are as described above.

[Protective layer forming step]
The method for producing a film mirror of the present invention comprises a protective layer forming composition obtained through the first filtration step described above, and a multilayer comprising a resin base material, a resin intermediate layer, and a reflective layer containing a metal in this order. A protective layer is formed by applying on the reflective layer of the structure.

The method for forming the protective layer is not particularly limited, and any forming method such as a thermal laminating method such as a coating method, a casting method, or a bonding method may be selected as long as the forming method is suitable for the material constituting the protective layer. Can do.
However, in order to adjust the number of foreign matters when forming the protective layer to 50 / cm ² or less, the protective layer forming step is preferably performed in a clean environment. By performing it in a clean environment, it is possible to suppress the entry of suspended fine particles in the atmosphere into the protective layer. Details of the clean environment method and cleanliness level are as described above.
Further, when forming a protective layer by coating, conventionally known methods such as gravure coating method, reverse coating method, die coating method, blade coater method, roll coater method, air knife coater method, screen coater method, bar coater method, curtain coater method, etc. Application method can be applied.

Hereinafter, the case where the protective layer which has resin is formed is demonstrated.
As a method for forming a protective layer in the present invention, for example, a composition for forming a protective layer containing a resin and optionally used components is dissolved in a solvent, applied onto the metal reflective layer, and then the solvent is reduced. Using a method for forming a protective layer, a method for forming a protective layer by casting on a metal reflective layer after heating to a temperature at which the resin contained in the composition for forming the protective layer melts, and a composition for forming the protective layer In advance, the film is formed into a film, and the resulting film is bonded onto the metal reflective layer via an adhesive, or fused onto the metal reflective layer by a method such as thermal lamination. And a method for forming a protective layer.

  From the viewpoint of uniformly forming a protective layer having excellent adhesion, the solid content concentration of the protective layer-forming composition is preferably in the range of 1% by mass to 30% by mass.

[Second filtration step]
In the manufacturing method of the film mirror of this invention, it is preferable to provide the 2nd filtration process which filters the composition for reflection layer formation previously before the below-mentioned reflection layer formation process. By providing the second filtration step, the number of foreign matters having an outer diameter of 1 μm or more in the reflective layer can be adjusted to 50 / mm ² or less.

In the second filtration step, the reflective layer forming composition is filtered using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less. By filtering the composition with a filter medium having a predetermined filtration accuracy, foreign matters in the liquid can be removed, and the number of foreign matters having an outer diameter of 1 μm or more can be reduced. Specifically, the number of foreign matters having an outer diameter of 1 μm or more per unit area of the reflective layer formed by coating or the like can be adjusted to 50 / mm ² or less.
Filtration may be performed once or a plurality of times for a single coating solution.

As the filter medium usable in the second filtration step, a commercially available product can be used, and a filtration filter having a pore size of 0.1 μm or more and 5 μm or less can be appropriately selected and used. . Specific examples include syringe filters such as Myrelex-LG and LH manufactured by Merck Millipore, membrane filters such as hydrophilic durapore, omnipore, hydrophobic surapore, florinert and mitex, DISMIC-25HP, 13HP manufactured by Advantech, etc. Syringe filters, hydrophilic PTFE type membrane filters, Acrodisc PTFE syringe filters, TF (PTFE) disc filters, Profile II, Nexis NXA, Nexis NXT, and other depth filters.
The filtration accuracy is preferably in the range of 0.1 μm to 3 μm from the viewpoint of further reducing the number of foreign matters having an outer diameter of 1 μm or more when the protective layer is formed.

In order to adjust the number of foreign substances in the reflective layer to 50 / mm ² or less, it is desirable that the second filtration step be performed in a clean environment. By carrying out in a clean environment, mixing of suspended fine particles in the atmosphere into the composition can be suppressed. Details of the clean environment method and cleanliness level are as described above.

[Reflective layer forming step]
The method for producing a film mirror of the present invention comprises a step of forming the reflective layer by applying the reflective layer forming composition obtained through the second filtration step described above on the resin intermediate layer. The embodiment is preferred.

The method for forming the reflective layer is not particularly limited, and either a wet method or a dry method may be applied. Examples of wet methods include plating methods such as electroplating. Examples of the dry method include a vacuum deposition method, a sputtering method, and an ion plating method.
However, in order to adjust the number of foreign matters when the reflective layer is formed to 50 / mm ² or less, it is desirable that the protective layer forming step be performed in a clean environment. By performing it in a clean environment, it is possible to suppress the entry of suspended fine particles in the atmosphere into the protective layer. Details of the clean environment method and cleanliness level are as described above.

Hereinafter, a case where the metal reflective layer is formed by a plating method will be described.
Compared with vapor deposition methods such as vacuum deposition and sputtering, sol-gel methods, and solvent coating methods, the plating method enables film formation corresponding to the surface shape of the film to be formed. It is preferable because the metal reflective layer can be formed with a thickness.
As the plating method, a conventionally known method can be used. Examples of the metal used for plating in this step include copper, chromium, lead, nickel, gold, silver, tin, and zinc. Silver is preferable from the viewpoint of the initial reflectivity of the film mirror. When using silver, a silver plating solution can be prepared, a silver plating solution can be provided on a resin intermediate layer or a protective layer, and a silver reflective layer can be formed by a plating method.

  Examples of metal compounds used for plating include silver nitrate, silver acetate, silver sulfate, silver carbonate, silver methanesulfonate, silver ammonia, silver cyanide, silver thiocyanate, silver chloride, silver bromide, silver chromate, and chloranil. Examples thereof include silver compounds such as silver oxide, silver salicylate, silver diethyldithiocarbamate, silver diethyldithiocarbamate, and silver p-toluenesulfonate. Among these, silver nitrate or silver methanesulfonate is preferable from the viewpoint of environmental impact and smoothness.

[Third filtration step]
In the manufacturing method of the film mirror of this invention, it is preferable to provide the 3rd filtration process which filters the composition for resin intermediate | middle layer formation beforehand before the below-mentioned resin intermediate | middle layer formation process. By providing the third filtration step, the number of foreign matters having an outer diameter of 1 μm or more in the resin intermediate layer can be adjusted to 50 pieces / mm ² or less.

In the third filtration step, the resin intermediate layer forming composition is filtered using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less. By filtering the composition with a filter medium having a predetermined filtration accuracy, foreign matters in the liquid can be removed, and the number of foreign matters having an outer diameter of 1 μm or more can be reduced. Specifically, the number of foreign substances having an outer diameter of 1 μm or more per unit area of the resin intermediate layer formed by coating or the like can be adjusted to 50 / mm ² or less.
Filtration may be performed once or a plurality of times for a single coating solution.

As the filter medium usable in the third filtration step, a commercially available product can be used, and a filtration filter having a pore size of 0.1 μm or more and 5 μm or less can be appropriately selected and used. . Specific examples include syringe filters such as Myrelex-LG and LH manufactured by Merck Millipore, membrane filters such as hydrophilic durapore, omnipore, hydrophobic surapore, florinert and mitex, DISMIC-25HP, 13HP manufactured by Advantech, etc. Syringe Filters, Hydrophilic PTFE Type Membrane Filters, Pole Acrodisc PTFE Syringe Filters, TF (PTFE) Disc Filters, Depth Filters such as Profile II, Nexis NXA, Nexis NXT, and Pleated Depth Filters such as Profile Star And pleated filters such as HDCII and Polyfine II.
The filtration accuracy is preferably in the range of 0.1 μm to 3 μm from the viewpoint of further reducing the number of foreign matters having an outer diameter of 1 μm or more when the resin intermediate layer is formed.

In order to adjust the number of foreign substances in the resin intermediate layer to 50 / mm ² or less, it is desirable that the third filtration step be performed in a clean environment. By carrying out in a clean environment, mixing of suspended fine particles in the atmosphere into the composition can be suppressed. Details of the clean environment method and cleanliness level are as described above.

[Resin intermediate layer forming step]
The method for producing a film mirror of the present invention includes a step of forming a resin intermediate layer by applying the resin intermediate layer forming composition obtained through the third filtration step described above onto a resin base material. The aspect comprised by these is preferable.

Hereinafter, the process of forming the resin intermediate layer will be described in detail.
The resin intermediate layer can be configured by providing an easy-adhesion layer or a plating undercoat polymer layer, and the film mirror manufacturing method of the present invention includes a step of forming an easy-adhesion layer as the resin intermediate layer formation step, and A step of forming a plating undercoat polymer layer may be provided.

-Formation of an easy adhesion layer-
The easy-adhesion layer in the present invention is obtained by dissolving each component constituting the easy-adhesion layer in a solvent that can be dissolved, and then applying it to a resin substrate by a method such as coating, and hardening it by heating or light irradiation. Can be formed.
The easy-adhesion layer is preferably formed by hardening and / or light irradiation. In particular, when the film is dried by heating and then subjected to light irradiation to obtain a pre-cured film, when the polymerizable compound is contained, a certain degree of curing is performed in advance. Therefore, after fixing a plating undercoat polymer layer on the surface of an easy-adhesion layer, the situation of dropping off with the easy-adhesion layer can be effectively suppressed.
The heating temperature and time may be selected under such conditions that the coating solvent can be sufficiently dried. From the viewpoint of suitability for production, the drying temperature is 190 ° C. or less and the drying time is within 10 minutes. More preferably, the drying temperature is 40 ° C. or higher and 180 ° C. or lower, and the drying time is within 5 minutes.

The easy adhesion layer is formed on a resin base material by applying a known layer forming method such as a coating method, a transfer method, or a printing method.
The solvent used when forming the easy-adhesion layer by coating is not particularly limited as long as it can dissolve the above components. From the viewpoint of ease of drying and workability, a solvent having a boiling point that is not too high is preferable. Specifically, a solvent having a boiling point of about 40 ° C. or higher and 150 ° C. or lower may be selected.
Specifically, cyclohexanone, methyl ethyl ketone, or the like can be used. The above exemplified solvents can be used alone or in combination. The concentration of the solid content in the coating solution is suitably 2% by mass or more and 50% by mass or less.

-Formation of plating undercoat polymer layer-
The plating undercoat polymer layer containing the plating undercoat polymer and the reduced metal particles is obtained by applying a composition containing a metal precursor and a plating undercoat polymer on the surface of the resin substrate or the easy adhesion layer provided on the resin substrate. A method of forming a plating undercoat polymer layer by coating or the like and applying energy, or using a composition containing a plating undercoat polymer, a layer is formed on the surface of a resin substrate or an easy-adhesion layer provided on the resin substrate. After the formation, the composition containing the metal precursor is brought into contact with this layer by a method such as dipping to form a polymer layer containing the metal precursor, and it can be suitably formed by a method of applying energy, etc. it can.

  When the plating base coating polymer layer is directly provided on the resin substrate, it is preferable to perform an easy adhesion treatment such as applying energy to the surface of the resin substrate in advance.

The coating amount of the polymer layer forming composition comprising a plating undercoat polymer, from the viewpoint of sufficient interaction formed with the later-described metal precursor, is in terms of solid content 0.05 g / m ² or more 10 g / m ² or less Particularly preferred is 0.3 g / m ² or more and 5 g / m ² or less.
The coating solution of the composition for forming a polymer layer containing a plating undercoat polymer applied to a resin substrate or the like is dried at 20 ° C. to 60 ° C. for 1 second to 2 hours, and then dried at a temperature exceeding 60 ° C. for 1 second to 2 hours. Preferably, after drying at 20 ° C. to 60 ° C. for 1 second to 20 minutes, it is more preferable to dry at a temperature exceeding 60 ° C. for 1 second to 20 minutes.

  The polymer layer forming composition containing a plating undercoat polymer is polymerized in the energy application region by applying energy after contacting the resin base material or an easy adhesion layer provided on the resin base material. Interaction is formed between the functional groups or the polymerizable group of the polymer and the resin base material or the easy adhesion layer, and on the resin base material (or on the resin base material through the easy adhesion layer). An immobilized polymer layer is formed. Thereby, a resin base material and a polymer layer adhere | attach firmly.

Examples of the energy application method include heating and exposure.
As an energy application method by exposure, specifically, light irradiation by a UV lamp, visible light, or the like is possible. Examples of the light source used for exposure include a mercury lamp, a metal halide lamp, a xenon lamp, and a chemical lamp. Examples of radiation include electron beams, X-rays, ion beams, and far infrared rays. Further, g-line, i-line, deep-UV light, and high-density energy beam (laser beam) are also used.
Exposure power, in order to polymerization easily proceed, and because to suppress the decomposition of the polymer, or polymer good for forming an interaction, from the viewpoint 10 mJ / cm ² or more such 8000 mJ / cm ² or less in the range it is preferably, and more preferably 100 mJ / cm ² or more 3000 mJ / cm ² or less.
Note that exposure may be performed in an atmosphere in which substitution with an inert gas such as nitrogen, helium, or carbon dioxide is performed, and the oxygen concentration is suppressed to 600 ppm or less, preferably 400 ppm or less.

Energy application by heating can be performed by, for example, a general heat heat roller, laminator, hot stamp, electric heating plate, thermal head, laser, blower dryer, oven, hot plate, infrared dryer, heating drum, or the like.
In addition, when energy is applied by heating, the temperature is preferably in the range of 20 ° C. or higher and 200 ° C. or lower in order to facilitate polymerization and to suppress thermal denaturation of the resin base material. It is more preferable that the temperature be in the range of from ° C to 120 ° C.

After energy application, a step of removing unreacted polymer may be provided as appropriate.
The film thickness of the plating undercoat polymer layer is not particularly limited, but is preferably 0.05 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 5 μm or less from the viewpoint of adhesion to a resin base material or the like. .
Further, the surface roughness (Ra) of the polymer layer obtained by the above method is preferably 20 nm or less, more preferably 10 nm or less, from the viewpoint of reflection performance.

<Sunlight reflector>
The sunlight reflecting plate of the present invention is configured by providing the film mirror of the present invention and a support material. The film mirror alone of the present invention can also be used for collecting sunlight, but is preferably used as a sunlight reflecting plate by holding the film mirror on a substrate or the like.

The film mirror of the present invention is excellent in durability and can exhibit high reflectance over a long period of time while maintaining the characteristics of the film mirror that is lightweight and flexible. The reflector is particularly suitable for photovoltaic power generation.
Moreover, it is possible to realize more efficient sunlight collection by providing a sunlight tracking system that tracks the sun's diurnal motion.

Examples of the support material include a substrate holding a film mirror and a frame-shaped member.
As a board | substrate, resin, a metal, or a ceramic is mentioned, for example, Preferably it is a metal. Examples of the metal substrate include steel plates, copper plates, aluminum plates, copper-plated steel plates, tin-plated steel plates, aluminum-plated steel plates, stainless steel plates, chromium-plated steel plates, and the like, and among them, corrosion resistance viewpoints. Therefore, a plated steel plate, a stainless steel plate, or an aluminum plate is preferable.

  When the film mirror and the substrate are bonded together, the material used for the bonding is not particularly limited, and examples thereof include an adhesive, a laminating agent, a heat sealant, and the like, and an adhesive is preferable from the viewpoint of specularity. As the adhesive, for example, an acrylic resin, a urethane resin, a polyester resin, a polyvinyl acetate resin, a nitrile rubber or the like is preferable, and from the viewpoint of light resistance and adhesiveness, an acrylic resin or An adhesive mainly composed of a urethane resin is particularly preferable. An acrylic adhesive mainly composed of an acrylic resin is particularly excellent in weather resistance and light resistance. Moreover, the urethane adhesive which has urethane resin as a main component can obtain strong adhesive strength by using a two-component mixed adhesive composed of polyisocyanate and polyol.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist thereof. Unless otherwise specified, “part” is based on mass.

[Formation of resin intermediate layer]
As the resin intermediate layer, a plating undercoat polymer layer was formed as follows.
-Preparation of coating solution for forming undercoat polymer layer-
To a mixed solution of 7 parts of acrylic polymer 1 having the following structure, 74 parts of 1-methoxy-2-propanol and 19 parts of water, 0.35 part of a photopolymerization initiator (Esacure KTO-46, manufactured by Lamberdy) was added. By stirring, a coating solution for forming an undercoat polymer layer (acrylic polymer solution; coating solution for forming a resin intermediate layer) was prepared. The prepared coating solution for forming an undercoat polymer layer was subjected to a filtration treatment through a filtration filter shown in Table 1 below to remove mixed foreign matters.

-Formation of plating undercoat polymer layer-
On the surface of a polyethylene terephthalate (PET) film (Cosmo Shine A-4300, thickness: 100 μm, manufactured by Toyobo Co., Ltd.) as a resin substrate, a coating solution for forming a plating undercoat polymer layer prepared by the above method is used as a film after drying. It was applied by a bar coating method so that the thickness was about 0.55 μm. After application, the film was dried at 25 ° C. for 10 minutes and at 80 ° C. for 5 minutes. Thereafter, UV exposure (wavelength: 254 nm, UV exposure: 1000 mJ / cm ² ) was performed using a UV irradiation device (UV lamp: metal halide lamp, manufactured by GS Yuasa). Next, the UV-exposed PET film was immersed in a 1% by mass aqueous sodium hydrogen carbonate solution for 5 minutes and then washed by pouring with pure water for 1 minute to remove unreacted polymer.
As described above, a plating undercoat polymer layer having a thickness of 0.5 μm was formed as a resin intermediate layer (undercoat layer) on the surface of the PET film.

(3) Application of reduced metal particles-Application of metal precursor-
As a solution containing a metal precursor, a 1% by mass aqueous solution of silver nitrate was prepared. The PET film on which the plating undercoat polymer layer was formed as described above was immersed in a 1% by mass silver nitrate aqueous solution whose temperature was adjusted to 25 ° C. for 5 minutes. Then, it wash | cleaned by pouring for 1 minute with a pure water, and provision of the metal precursor was performed.

-Reduction of metal precursor-
Subsequently, a 0.25% by mass formaldehyde aqueous solution containing 0.14% by mass sodium hydroxide was prepared as a reducing solution. The PET film provided with the metal precursor was immersed for 1 minute in the above reducing solution whose temperature was adjusted to 25 ° C. Then, it washed by pouring with pure water for 1 minute, the metal precursor was reduced, and the metal particle was made to adhere.
When the surface resistance value after the reduction was measured using a surface resistance meter, it was about 10Ω / □. Moreover, when the surface roughness (Ra) was measured using an atomic force microscope (AFM), it was about 7 nm. Furthermore, when the particle diameter of the metal after reduction was measured using a scanning electron microscope (SEM), it was about 50 nm.

  The series of steps for forming the resin intermediate layer was performed in a clean environment of class 10000 which is cleaned by a cleaning filter in order to reduce airborne dust.

[Formation of silver reflective layer]
−Pretreatment−
As a pre-treatment for electroplating, Dyne Cleaner AC100 (manufactured by Daiwa Kasei Co., Ltd.) obtained by controlling the temperature of the PET film having the plating undercoat polymer layer containing the reduced metal particles obtained above to 25 ° C. For 30 seconds. Then, it was washed several times. Subsequently, as a pretreatment for electroplating, it was immersed in a 10% by mass aqueous solution of Dyne Silver ACC (main component: methanesulfonic acid, manufactured by Daiwa Kasei Co., Ltd.) for 10 seconds and washed several times.

-Electroplating-
Next, as an electroplating solution, Dyne Silver Bright PL50 (main component: silver methanesulfonate, manufactured by Daiwa Kasei Co., Ltd.) was adjusted to pH 8.0 with 8M potassium hydroxide. The electroplating solution after pH adjustment was subjected to a filtration treatment through a filtration filter shown in Table 1 below to remove foreign matters mixed therein. Subsequently, the PET film pretreated as described above was immersed in this electroplating solution and plated at 0.5 A / cm ^{2 for} 20 seconds.
Thereafter, as a post-treatment of electroplating, the plated PET film was immersed in a 10% by mass aqueous solution of Dyne Silver ACC (trade name: manufactured by Daiwa Kasei Co., Ltd.) for 90 seconds and then washed several times.
As described above, a silver reflective layer having a thickness of 0.1 μm was formed. When the surface roughness (Ra) of this silver reflective layer was measured using an atomic force microscope (AFM), it was about 4 nm.

  The series of steps for forming the silver reflection layer was performed in a clean environment of class 10000 which is cleaned by a cleaning filter in order to reduce airborne dust.

[Formation of protective layer]
Each component in the following composition was mixed and subjected to a filtration treatment through a filtration filter shown in Table 1 below to remove foreign matter, thereby preparing a coating solution for forming a protective layer. Subsequently, this protective layer forming coating solution is applied to the plating surface of the silver reflective layer by a bar coating method so that the dry film thickness is 10 μm, and dried at 130 ° C. for 1 minute to form a protective layer. did.

<Composition of coating solution for forming protective layer>
・ Acrylic resin: 21 parts (Dianar BR-102, manufactured by Mitsubishi Rayon Co., Ltd .; binder)
・ Benzotriazole-based UV absorber: 4 parts (Sumisorb 250, manufactured by Sumitomo Chemical Co., Ltd .; UV absorber)
・ Cyclohexanone (solvent) 5 parts ・ Methyl ethyl ketone (solvent) 70 parts ・ Fluorosurfactant 0.04 parts (Megafac F-780F (solid content: 30% by mass), DIC ( Co., Ltd .; coating aid)

  The series of steps for forming the protective layer was performed in a class 10000 clean environment where the air was cleaned with a cleaning filter in order to reduce airborne dust.

  As described above, a film mirror having a multilayer structure of PET film / plated undercoat polymer layer / silver reflective layer / protective layer was produced.

[Evaluation]
The film mirror produced as described above was subjected to the following measurements and evaluations. The results of measurement and evaluation are shown in Table 1 below.

-1. Number of foreign matter in protective layer
A 10 cm square sample piece was cut out from each of the produced film mirrors at five locations, and for each of them, the protective layer as the outermost layer was observed with a digital microscope VHX-500 (Keyence Corporation) at a magnification of 500 times. The number (number / cm ² ) of foreign matters having a diameter (maximum length of foreign matter) of 10 μm or more was measured. And the average value of the measured value was calculated | required.

-2. Number of foreign matter in resin intermediate layer
The protective layer of each produced film mirror was dissolved and removed with a mixed solvent (mixed solution of cyclohexanone: MEK [mass ratio] = 70: 5) and washed with acetone. Thereafter, the silver reflective film was dissolved and removed with a 60% by mass concentrated nitric acid aqueous solution, and 10 cm square sample pieces were cut out from five locations from the sample washed with pure water. Each of the sample pieces is observed with a digital microscope VHX-500 (Keyence Co., Ltd.) at a magnification of 3000 times, and the number of foreign matters having an outer diameter (maximum length of foreign matter) of 1 μm or more (pieces / mm ² ) is obtained. Measured. And the average value of the measured value was calculated | required.

-3. Number of foreign matter in the silver reflective layer
The protective layer of each produced film mirror was dissolved and removed with a mixed solvent (mixed solution of cyclohexanone: MEK [mass ratio] = 70: 5), and 10 cm square sample pieces were cut out from 5 locations from a sample washed with acetone. It was. Each of the sample pieces is observed with a digital microscope VHX-500 (Keyence Co., Ltd.) at a magnification of 3000 times, and the number of foreign matters (outside / mm ² ) whose outer diameter (maximum length of foreign matter) is 1 μm or more is determined. Measured. And the average value of the measured value was calculated | required.

-4. Durability
Each film mirror is placed in a thermo-hygrostat (manufactured by Espec Corp., PR-3J) and allowed to stand for 1000 hours under environmental conditions of a temperature of 85 ° C. and a humidity of 85% RH. A decrease in reflectance of light (= reflectance before leaving (%) − reflectance after leaving (%)) was determined and evaluated according to the following evaluation criteria. The reflectance was measured using an ultraviolet-visible near-infrared spectrophotometer UV-3100 (manufactured by Shimadzu Corporation). As for durability, evaluation levels A to C are in an allowable range from a practical viewpoint.
<Evaluation criteria>
A: The decrease in reflectance is less than 3%.
B: Decrease in reflectance is 3% or more and less than 5%.
C: The decrease in reflectance is 5% or more and less than 10%.
D: Decrease in reflectance is 10% or more.

Details of the filtration filter in Table 1 are as follows.
-Filtration filter with a filtration accuracy of 10 μm: Omnipore JCWP (manufactured by Merck Millipore)
-Filtration filter with a filtration accuracy of 5 μm: Omnipore JMWP (manufactured by Merck Millipore)
-Filtration filter with a filtration accuracy of 1 μm: Omnipore JAWP (Merck Millipore)
-Filtration filter with a filtration accuracy of 0.5 μm: Omnipore JHWP (manufactured by Merck Millipore)

As shown in Table 1, in the example in which the number of foreign matters having an outer diameter of 10 μm or more is 50 pieces / cm ² or less in the protective layer, the reflectance is higher than that of the comparative example in which the number of foreign matters exceeds 50 pieces / cm ² . The decrease, that is, deterioration of silver was suppressed, and excellent durability performance was exhibited. Further, even if the number of foreign matters in the protective layer is 50 pieces / cm ² or less, if the number of foreign matters having an outer diameter of 1 μm or more in the silver reflective layer and / or the resin intermediate layer exceeds 50 pieces / mm ² , the silver deteriorates. There was a tendency for the suppression effect to decrease, the reflectance to decrease, and the durability to decrease.
On the other hand, in the comparative examples in which the number of foreign matters having an outer diameter of 10 μm or more in the protective layer exceeds 50 / cm ² , the reflectance declined with time and the desired durability could not be ensured. .

Claims (12)

A film having a resin base material, a resin intermediate layer, a reflective layer containing a metal, and a protective layer having a thickness of 30 μm or less and a foreign layer having an outer diameter of 10 μm or more of 50 / cm ² or less in this order. mirror.   The film mirror according to claim 1, wherein the protective layer is in contact with a surface of the reflective layer. 3. The film mirror according to claim 1, wherein the resin intermediate layer has a thickness of 0.05 μm or more and 3 μm or less, and the number of foreign matters having an outer diameter of 1 μm or more is 50 pieces / mm ² or less. The film according to any one of claims 1 to 3, wherein the thickness of the reflective layer is 0.05 µm or more and 0.5 µm or less, and the number of foreign matters having an outer diameter of 1 µm or more is 50 pieces / mm ² or less. mirror.   The film mirror according to any one of claims 1 to 4, wherein the metal contained in the reflective layer is silver.   The said resin intermediate | middle layer is a plating undercoat polymer layer containing a metal particle, The film mirror of any one of Claims 1-5.   The film mirror of any one of Claims 1-6 used for condensing sunlight.   A solar reflector comprising the film mirror according to any one of claims 1 to 7 and a support material. A first filtration step of filtering the protective layer-forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 10 μm or less;
A protective layer forming step of forming a protective layer by applying the protective layer-forming composition after filtration onto the reflective layer having a multilayer structure having a resin base material, a resin intermediate layer, and a reflective layer containing a metal in this order. When,
The manufacturing method of the film mirror which has this. A second filtration step of filtering the reflective layer forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less;
A reflective layer forming step of forming a reflective layer containing the metal by applying the reflective layer forming composition after filtration onto the resin intermediate layer constituting the multilayer structure;
The method for producing a film mirror according to claim 9, further comprising: In the second filtration step, a silver plating solution is filtered as the reflective layer forming composition,
The said reflective layer formation process is a manufacturing method of the film mirror of Claim 10 which forms a silver reflective layer as a reflective layer containing the said metal by the plating method using the silver plating liquid after filtration. A third filtration step of filtering the resin intermediate layer forming composition using a filter medium having a filtration accuracy of 0.1 μm or more and 5 μm or less;
A resin intermediate layer forming step of forming the resin intermediate layer by applying the resin intermediate layer forming composition after filtration onto the resin base material constituting the multilayer structure;
The manufacturing method of the film mirror of any one of Claims 9-11 which further has these.