JP2017024195A - mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror which can prevent occurrence of warpage of a substrate, makes a surface of the substrate on a side where a reflection layer is formed less likely to deteriorate, makes the surface of the substrate on a side where light is incident less likely to deteriorate, and is excellent in long-term reliability.SOLUTION: There is provided a mirror which includes a resin substrate, and has a first hard coat layer and a reflection layer formed sequentially from the side of a first main surface of the substrate, and a second hard coat layer and a ceramic layer formed sequentially from the side of a second main surface side facing the first main surface of the substrate; and is structure so as to reflect light having passed through the inside of the substrate by the reflection layer, where a thickness difference between the first hard coat layer and the second hard coat layer formed on both main surfaces of the substrate is represented by formula (1): -3≤[thickness of first hard coat layer-thickness of second hard coat layer)/thickness of first hard coat layer]×100≤3.SELECTED DRAWING: Figure 2

Description

The present invention relates to a mirror.

Patent Document 1 discloses a composite film having a metal reflective layer on the surface of a resin substrate and further having a hard coat layer on the metal reflective layer, wherein the hard coat layer contains polysilazane and a siloxane compound. A composite film that is a cured product of the adhesive composition is disclosed.

FIG. 3 is a cross-sectional view schematically showing the composite film disclosed in Patent Document 1. In this composite film 100, the metal reflective layer 102 and the hard coat layer 103 are sequentially formed on the resin base material 101. It is considered to be used as a mirror. In that case, light such as sunlight is reflected on the back surface of the resin base material 101 on which the metal reflective layer 102 is formed after passing through the resin base material 101, passes through the inside of the resin base material 101, and then in the air. Get out. Therefore, the resin base material 101 and the metal reflective layer 102 are required to be in close contact and flat.

JP 2013-230561 A

However, when the metal reflective layer 102 is directly formed on the resin base material 101, the surface of the resin base material 101 is likely to be deteriorated by the metal, and unevenness or the like is easily formed on the surface of the resin base material 101. There was a problem that the characteristics as a mirror were liable to deteriorate.
Further, when the hard coat layer 103 is formed only on one side of the resin base material 101, there is a problem that the resin base material 101 having a lower strength than glass or the like is likely to warp.

The present invention has been made in view of the above problems, and is a mirror in which a reflective layer is formed on a substrate surface side opposite to a substrate surface on which light is incident, and the substrate is warped. It is possible to prevent the occurrence of the occurrence of the mirror, the surface of the base on which the reflective layer is formed is hardly deteriorated, the surface of the base on which light is incident is hardly deteriorated, and a mirror having excellent long-term reliability is provided. Objective.

A mirror of the present invention for solving the above-described problems is a resin base, a first hard coat layer and a reflective layer formed sequentially on the first main surface side of the base, and a first base of the base. A mirror composed of a second hard coat layer and a ceramic layer sequentially formed on the second main surface side facing the main surface, and configured to reflect the light that has passed through the inside of the substrate by the reflection layer. The difference in thickness between the first hard coat layer and the second hard coat layer formed on both main surfaces of the substrate is expressed by the following formula (1). .
−3 ≦ [(thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100 ≦ 3 (1)

The mirror of the present invention is configured to reflect the light that has passed through the inside of the substrate by the reflection layer, as in the case of a normal mirror, but since the hard coat layers are formed on both main surfaces of the substrate, It is possible to prevent the surface of the skin from being damaged. Further, since there is almost no difference in the thickness of the two hard coat layers formed on both sides of the base as shown in the above formula (1), it is possible to prevent the mirror from warping. it can. Further, when the reflective layer is formed directly on the first main surface side of the base, the base may be deteriorated by the environment when the reflective layer is formed, for example, temperature, but the first main surface of the base Since the reflection layer is formed on the side through the first hard coat layer, there is no possibility that the substrate is deteriorated by the reflection layer. Furthermore, the outermost layer on the second main surface side of the substrate is formed with a ceramic layer having more excellent wear resistance and mechanical properties, so that it has excellent durability and long-term reliability as a mirror.
Moreover, the 1st hard-coat layer formed in the 1st main surface side is excellent also in adhesiveness with a base | substrate and a reflection layer.

When the difference in thickness between the first hard coat layer and the second hard coat layer is out of the range of the above formula (1), that is, expressed by the following formula (2) or (3) In this case, the substrate is likely to warp.
−3> [(thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100 (2)
[(Thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100> 3 (3)

In the mirror of the present invention, the first hard coat layer and the second hard coat layer are preferably made of silicone resin, acrylic resin, or silica hybrid composite.
In the mirror, when the first hard coat layer and the second hard coat layer are made of a silicone-based resin, an acrylic resin, or a silica hybrid composite, the substrate has excellent adhesion to the substrate, and the substrate It is possible to reliably prevent warping from occurring.

In the mirror according to the aspect of the invention, it is preferable that the ceramic layer covers the surface of the second hard coat layer and covers the side surface of the second hard coat layer and at least a part of the side surface of the base.
In the mirror, when the ceramic layer covers the surface of the second hard coat layer, and covers the side surface of the second hard coat layer and at least a part of the side surface of the substrate, moisture or the like enters from the side surface of the substrate. Thus, deterioration of the substrate surface and the hard coat layer can be prevented.

In the mirror of the present invention, the entire periphery including the side surfaces of the first hard coat layer and the reflective layer, which are sequentially formed on the first main surface side of the substrate, is covered with a coating resin layer, and at least It is preferable that a part of the side surface of the substrate is also covered with the coating resin layer.
In the mirror, the entire periphery including the side surfaces of the first hard coat layer and the reflective layer is covered with a coating resin layer, and at least a part of the side surface of the base is also covered with the coating resin layer. Then, it is possible to prevent the hard coat layer and the reflective layer from deteriorating due to the entry of air, moisture or the like from the side surface of the substrate.

The coating resin may cover the entire side surface of the substrate, or may be formed to further cover the ceramic layer covering the side surface of the substrate. In this case, it is possible to more reliably prevent the hard coat layer and the reflective layer from being deteriorated.

In the mirror of the present invention, the ceramic layer includes SiC, WC, TiC, TaC, ZrC, VC, HfC, B ₄ C, Mo ₂ C, NbC, Cr ₃ C ₂ , Si ₃ N ₄ , TiN, AlN, BN. A ceramic layer made of at least one selected from the group consisting of ZrN, TaN, NbN, Cr ₂ N, VN and HfN is preferable.

Non-oxide ceramics such as the above-mentioned carbide ceramics or nitride ceramics are generally known for their poor wettability with respect to water and organic materials. For this reason, it is difficult for foreign matters such as dust to be collected on the side surface of the mirror, and for example, it is difficult to cause mirror damage due to foreign matter biting during construction of the mirror, so that a highly reliable system can be realized. In particular, SiC has the properties of a semiconductor, and it is difficult to collect dust and dust due to static electricity. Therefore, when SiC is used, the above-described effects are remarkable.

In the mirror of the present invention, the hard coat layer preferably contains a translucent filler.
In the mirror, when the hard coat layer contains the filler, the weather resistance can be improved. In particular, in order to improve the weather resistance, it is desirable that the filler is contained in the second hard coat layer through which light passes.
Further, when the filler is contained in the hard coat layer, the mechanical properties of the hard coat layer are improved, the mirror is not easily broken, and the substrate is less likely to warp.

In the mirror of the present invention, the ceramic layer is preferably made of SiC.
In the above mirror, SiC is excellent in mechanical properties and durability, and is excellent in heat resistance and thermal conductivity, and therefore can be more suitably used as a ceramic layer.

In the mirror of the present invention, the thickness of the hard coat layer is preferably 1 to 10 μm.
In the mirror, when the thickness of the hard coat layer is 1 to 10 μm, the mirror can be more reliably prevented from warping.
When the thickness of the hard coat layer is less than 1 μm, it is difficult to prevent the mirror from warping because the hard coat layer is too thin. On the other hand, when the thickness of the hard coat layer exceeds 10 μm Since the hard coat layer is too thick, the characteristics as a mirror are easily deteriorated.

In the mirror of the present invention, the thickness of the ceramic layer is preferably 10 to 500 nm.
In the mirror of the present invention, when the thickness of the ceramic layer is 10 to 500 nm, it can be formed relatively easily by sputtering or the like, and sufficiently satisfies the required mechanical properties and durability conditions. it can.

If the thickness of the ceramic layer is less than 10 nm, the thickness of the ceramic layer is too thin, so that the mechanical properties and durability are insufficient.
On the other hand, even if the thickness of the ceramic layer exceeds 500 nm, there is no significant change in characteristics, and it is difficult to form a ceramic layer with such a thickness, and it takes time, so the process tact is long. The mirror becomes expensive.

In the mirror of the present invention, the reflective layer is preferably made of at least one selected from the group consisting of Ag, Au, Al, Cr, Ni, and Pt.

In the mirror of the present invention, when the reflective layer is made of at least one selected from the group consisting of Ag, Au, Al, Cr, Ni and Pt, the characteristics as the reflective layer can be sufficiently exhibited.

FIG. 1 is a cross-sectional view schematically showing an example of the mirror of the first aspect of the present invention. FIG. 2 is a cross-sectional view schematically showing an example of the mirror of the second aspect of the present invention. FIG. 3 is a cross-sectional view schematically showing the composite film disclosed in Patent Document 1. As shown in FIG.

(Detailed description of the invention)
Hereinafter, the mirror of the present invention will be described in detail.

The mirror of the present invention includes a resin base, a first hard coat layer and a reflective layer formed in order on the first main surface side of the base, and a second main surface facing the first main surface. A mirror composed of a second hard coat layer and a ceramic layer sequentially formed on the surface side, and configured to reflect light that has passed through the inside of the substrate by the reflection layer;
The difference in thickness between the first hard coat layer and the second hard coat layer formed on both main surfaces of the substrate is expressed by the following equation (1).
−3 ≦ [(thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100 ≦ 3 (1)

In the mirror of the present invention, since the hard coat layers are formed on both main surfaces of the substrate, the surface of the substrate can be prevented from being damaged. Further, since there is almost no difference in the thickness of the formed hard coat layer as described above, it is possible to prevent the mirror from warping. Further, when the reflective layer is formed directly on the first main surface side of the base, the base may be deteriorated by the environment when the reflective layer is formed, for example, temperature, but the first main surface of the base Since the reflection layer is formed on the side through the first hard coat layer, there is no possibility that the substrate is deteriorated by the reflection layer. Further, since the ceramic layer having excellent wear resistance and mechanical properties is formed on the second main surface side of the substrate by the outermost layer, it is excellent in durability and has long-term reliability as a mirror. Moreover, the 1st hard-coat layer formed in the 1st main surface side is excellent also in adhesiveness with a base | substrate and a reflection layer.

Examples of the mirror of the present invention include the following configurations.
The mirror according to the first aspect of the present invention includes a base, a first hard coat layer and a reflective layer sequentially formed on the first main surface side of the base, a side surface of the first hard coat layer, and a main surface and side surfaces of the reflective layer. And a second hard coat layer and a ceramic layer which are sequentially formed on the second main surface side facing the first main surface of the substrate. It consists of.
In the mirror having the above-described configuration, the ceramic layer is formed on the main surface of the second hard coat layer, and the ceramic layer covers the entire periphery of the second hard coat layer and covers a part of or the entire side surface of the substrate. It may be formed.

The shape, structure and the like of the above-described first mirror of the present invention will be further described in detail.
FIG. 1 is a cross-sectional view schematically showing an example of the mirror of the first aspect of the present invention.
A mirror 10 shown in FIG. 1 includes a base 11, a first hard coat layer 12 and a reflective layer 13 that are sequentially formed on the first main surface 11a side of the base 11, and a side surface 12b of the first hard coat layer 12 and a reflection. A covering resin layer 14 that covers the main surface 13a and the side surface 13b of the layer 13 and further covers the side surface 11c of the substrate 11;
It consists of a second hard coat layer 15 and a ceramic layer 16 which are sequentially formed on the second main surface 11b side facing the first main surface 11a of the substrate 11.

In the substrate, incident light passes through the ceramic layer, the second hard coat layer, and the inside of the substrate, and is reflected by the reflective layer formed on the substrate surface side opposite to the substrate surface on which the light is incident. The reflected light passes through the inside of the substrate, the second hard coat layer and the ceramic layer and is emitted from the surface of the ceramic layer. Since the emitted light is used in the mirror of the first aspect of the present invention, it is desirable that the emitted light (reflected light) is less attenuated than the incident light and has sufficient intensity.

The substrate constituting the mirror of the first aspect of the present invention is made of a resin, and the substrate preferably has a light-transmitting property that allows light having a wavelength in the range of more than 240 nm and less than 2600 nm to pass through at least 85%. It is more desirable to pass 90% or more of light in the range.
The thickness of the substrate is preferably 0.1 to 2.0 mm.

Examples of the translucent resin constituting the substrate include polyvinyl chloride (PVC), polycarbonate (PC), polyethylene terephthalate (PET), and acrylic resin (PMMA). Of these, polycarbonate (PC) is preferred.

In the mirror of the first aspect of the present invention, the surface roughness RzJIS of the substrate surface is preferably 1 to 50 nm. The surface roughness RzJIS described above is a ten-point average roughness defined by JIS B 0601 (2001).
When the surface roughness RzJIS of the substrate surface is less than 1 nm, the surface area of the substrate becomes small, and it becomes difficult to obtain sufficient adhesion between the substrate and the reflective layer. On the other hand, when the surface roughness RzJIS of the substrate surface exceeds 50 nm, it becomes difficult to form a flat reflective layer on the substrate surface, and the characteristics as a mirror deteriorate.
The surface roughness RzJIS of the substrate surface was measured by measuring the surface contour curve using a laser microscope (VK-X200 violet specification manufactured by Keyence Corporation), and then scanning distance was set to 30 μm in accordance with JIS B 0601 (2001). Can be measured.

A first hard coat layer is formed on the first main surface side of the substrate, and a second hard coat layer is formed on the second main surface side of the substrate.
The first hard coat layer and the second hard coat layer are preferably made of a silicone resin, an acrylic resin, or a silica hybrid composite.

The silicone-based resin is a combination of tetrafunctional tetraalkoxysilane as a main component and trialkoxysilane or the like, and finally, a three-dimensional structure of SiO is formed in the resin. The silicone resin can be cured by using a catalyst or by heating. Since the hard coat layer made of silicone resin has a three-dimensional structure of SiO, it is hard and has excellent wear resistance.

The acrylic resin is composed of a polyfunctional monomer / monofunctional monomer / polymer system, and the degree of crosslinking is controlled by the kind and amount of the polyfunctional monomer. Examples of the polyfunctional monomer include polyol acrylate, polyester acrylate, urethane acrylate, and epoxy acrylate. The hard coat layer made of an acrylic resin can be cured by ultraviolet rays. Curing with ultraviolet rays has a feature that it can be performed in a short time.

The silica hybrid composite is a combination of inorganic fine particles such as silica sol or the above-mentioned three-dimensional structure of SiO using a silicone resin and an acrylic resin or other resin used for forming a hard coat layer. Further, by combining a resin having a radical polymerizable acryloyl group (AC), a methacryloyl group (MAC), or a cationic polymerizable oxetanyl group (OX), it can be cured by light such as ultraviolet rays.

The hard coat layer preferably contains a translucent filler.
When the hard coat layer contains a translucent filler, the weather resistance can be improved. Examples of the filler include titania, indium-tin oxide (ITO), tin-antimony oxide (ATO), and glass fiber. Since the filler easily aggregates during production, it is desirable to disperse the filler using a dispersing agent such as a coupling agent.

The difference in thickness between the first hard coat layer and the second hard coat layer formed on both main surfaces of the substrate is expressed by the following formula (1).
−3 ≦ [(thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100 ≦ 3 (1)

That is, according to the formula (1), the thickness of the second hard coat layer may be thicker or thinner than the thickness of the first hard coat layer, based on the thickness of the first hard coat layer. However, the absolute value of the difference is less than 3%. The thickness of the first hard coat layer is desirably equal to the thickness of the second hard coat layer.
By setting the thickness of the first hard coat layer and the thickness of the second hard coat layer as described above, it is possible to prevent the substrate from warping. Further, the first hard coat layer and the second hard coat layer can protect the surface of the substrate and prevent the surface of the substrate from being damaged and the properties as a mirror from being deteriorated.

The first hard coat layer and the second hard coat layer preferably have a light-transmitting property that allows light having a wavelength in the range of more than 240 nm and less than 2600 nm to pass through at least 85%, and pass light in the above wavelength range through at least 90%. It is more desirable.

A reflective layer is formed on the main surface of the first hard coat layer formed on the first main surface side of the substrate constituting the mirror of the first invention.
The reflective layer has a function as a mirror that reflects light, and requires flatness.
The reflective layer is preferably made of at least one selected from the group consisting of Ag, Au, Al, Cr, Ni and Pt. Of these, Ag is particularly desirable.
The thickness of the reflective layer is desirably 50 to 200 nm.

Since the surface of the reflective layer on the substrate surface side functions as a mirror, the surface roughness RzJIS of the surface of the reflective layer on the substrate surface side is preferably 1 to 50 nm.
When the surface roughness RzJIS of the reflective layer is less than 1 nm, the adhesion with the hard coat layer is deteriorated. On the other hand, when the surface roughness RzJIS of the reflective layer is greater than 50 nm, the unevenness of the surface of the reflective layer is large. Therefore, the function as the reflective layer is deteriorated.

Examples of the resin that constitutes the covering resin layer that covers the side surface of the first hard coat layer and the main surface and side surface of the reflective layer, and further covers the side surface of the substrate include silicone resins and epoxy resins. These resins desirably contain a black pigment so as to absorb or reflect ultraviolet rays.
Examples of black pigments include carbon pigments such as graphite, iron oxides, complex oxides of copper and chromium, and complex oxides of copper, chromium, and zinc.

By forming the coating resin layer around the reflective layer and the first hard coat layer, it is possible to prevent the hard coat layer and the reflective layer from being deteriorated by ultraviolet rays or the like, and between the hard coat layer and the substrate and It can be prevented that air, water vapor, or the like enters between the hard coat layer and the reflective layer to deteriorate these layers.

In the mirror according to the first aspect of the present invention, the ceramic layer formed on the main surface of the second hard coat layer protects the second hard coat layer and the substrate from the outside atmosphere and damages the second hard coat layer and the substrate. Play a role in preventing.
For this reason, it is desirable that the ceramic layer is made of a carbide-based ceramic or a nitride-based ceramic.
If the ceramic layer is made of carbide ceramic or nitride ceramic, it is sufficiently hard and has excellent wear resistance, so the surface of the coating layer is less likely to be scratched even under harsh conditions, and long-term durability Excellent. In addition, it is difficult to collect foreign substances such as dust on the mirror, and a highly reliable system can be realized.

In the mirror of the first aspect of the present invention, SiC, WC, TiC, TaC, ZrC, VC, HfC, B ₄ C, Mo ₂ C, NbC, Cr ₃ C _{2 and the} like are used as the carbide-based ceramic constituting the ceramic layer. Can be mentioned. Examples of the nitride-based ceramic include Si ₃ N ₄ , TiN, AlN, BN, ZrN, TaN, NbN, Cr ₂ N, VN, and HfN.
In the first mirror of the present invention, the carbonitride ceramic is also included in the carbide ceramic or nitride ceramic, and examples of the carbonitride ceramic include tungsten carbonitride.
The ceramic layer may include only one of these carbide ceramics and nitride ceramics, or may include two or more carbide ceramics and nitride ceramics.
Among these, a ceramic having a high hardness is preferable, and a ceramic having a Vickers hardness of 500 to 10,000 HV is preferable. The ceramic layer is preferably SiC.

In the first mirror of the present invention, the ceramic layer is preferably amorphous. When the ceramic layer is amorphous, an action of absorbing ultraviolet rays can be exhibited even when the ceramic layer is thin, and the hard coat layer and the substrate can be prevented from being deteriorated by the ultraviolet rays.

In the mirror of the first aspect of the present invention, the thickness of the ceramic layer is preferably 10 to 500 nm, and more preferably 10 to 200 nm.
When the thickness of the ceramic layer is within the above range, the internal hard coat layer and the substrate are sufficiently protected, and sufficient wear resistance is imparted.
When the thickness of the ceramic layer is less than 10 nm, the thickness of the ceramic layer is too thin, so that the mechanical properties and durability are insufficient. Even if the thickness of the ceramic layer exceeds 500 nm, there is no significant change in the characteristics, and it is difficult to form a ceramic layer with such a thickness, and it takes time. It will be something.

In the mirror of the first aspect of the present invention, the thicknesses of the first hard coat layer, the second hard coat layer, the reflective layer, the ceramic layer, and the coating resin layer can be measured using, for example, a laser microscope.
Prepare a sample having a portion on which the first hard coat layer, the second hard coat layer, the reflective layer, the ceramic layer, or the coating resin layer is formed on the surface of the substrate and a portion on which the above-mentioned layer is not formed. The first hard coat layer is measured by scanning the laser microscope so as to cross the step at the boundary between the portion where the layer is formed and the portion where the layer is not formed, and measuring the height of the step. The thickness of the second hard coat layer, the reflective layer, the ceramic layer, and the coating resin layer can be measured.
The measurement sample may be prepared by masking a part of the first hard coat layer, the second hard coat layer, the reflective layer, the ceramic layer, and the coating resin layer to form the above-described layer. Alternatively, a part of the formed layer may be removed.

Next, the manufacturing method of the mirror of 1st this invention is demonstrated. Note that the steps described below are not necessarily performed sequentially, the order may be changed, and other steps may be inserted.
(A) Preparation of substrate In the first method of manufacturing a mirror of the present invention, a substrate is first prepared.
As the substrate, the materials described in the description of the substrate constituting the mirror of the first invention can be used. When a resin material is used as a substrate, a material formed by cutting, extrusion molding or the like into an arbitrary shape is prepared according to the intended use.

Further, it is preferable to perform a cleaning treatment in order to remove impurities on the surface of the substrate.
The cleaning process is not particularly limited, and a conventionally known cleaning process can be used. Specifically, for example, a method of performing ultrasonic cleaning in water or an alcohol solvent can be used.
Alternatively, the surface of the substrate may be plasma cleaned by installing the substrate in a sputtering apparatus and generating plasma. In this case, the hard coat layer may be formed by a method such as coating after plasma cleaning.

In addition, after the cleaning treatment, a mirror surface treatment or a roughening treatment may be performed on the surface of the substrate in order to adjust the surface roughness of the substrate, if necessary. Specifically, for example, a process such as a sandblast process or an etching process may be performed. These may be used alone or in combination of two or more.
A washing process may be further performed after the above process.
Since the material constituting the substrate and the preferable surface roughness of the substrate surface have already been described, the description thereof is omitted here.

(B) Formation of a hard coat layer When forming a hard coat layer, a film functioning as a hard coat layer is prepared in advance, and the hard coat layer is formed by pasting this film on a substrate. Also good.
Also, after preparing a hard coat composition by mixing a monomer or polymer that is a raw material of the hard coat layer, a solvent, a filler, etc., the hard coat composition is applied to a substrate and then applied by heating, ultraviolet irradiation, or the like. The layer may be cured to form a hard coat layer.
Examples of the method for applying the hard coat layer composition include spin coating, dipping, spraying, slide coating, bar coating, roll coating, gravure coating, and die coating.
It is desirable that the materials and compositions of the first hard coat layer and the second hard coat layer are the same, and the first hard coat layer and the second hard coat layer so that the thickness after curing satisfies the above formula (1). A coat layer is formed.

(C) Formation of reflective layer In the mirror manufacturing method of the first aspect of the present invention, the reflective layer is formed on the main surface of the hard coat layer by using a PVD (physical vapor deposition) method or the like.
Specific PVD (physical vapor deposition) methods include, for example, vapor deposition methods such as resistance heating vapor deposition, electron beam vapor deposition, and molecular beam epitaxy, ion plating, ion beam deposition, and sputtering.
Among these methods, the sputtering method is desirable, and the material such as Ag and Au is a metal and has conductivity, so that the DC (direct current) sputtering method is more desirable.

(D) Formation of Ceramic Layer In the first method for manufacturing a mirror of the present invention, a ceramic layer is formed on the main surface of the first hard coat layer.
The ceramic layer can be formed by a PVD (physical vapor deposition) method, similarly to the formation of the reflective layer.
When the ceramic layer is formed by physical vapor deposition, the temperature of the substrate does not become high, and the ceramic layer can be formed at a temperature lower than the heat resistant temperature of the resin material even when a resin material is used for the substrate. Therefore, it is suitable as a method for forming a ceramic layer.
Specifically, physical vapor deposition is preferably performed at 5 to 200 ° C. This temperature is a set temperature in the chamber, and is preferably room temperature (25 ° C. ± 15 ° C.).

In the mirror manufacturing method of the first aspect of the present invention, the physical vapor deposition method is preferably performed by sputtering, vacuum vapor deposition, ion plating, or ion beam vapor deposition.
Of these, sputtering is more preferable, and sputtering is preferably magnetron sputtering, ion beam sputtering, bipolar sputtering, reactive sputtering, or ECR sputtering.
In particular, RF (alternating current, high frequency) sputtering is preferable, and RF magnetron sputtering is more preferable.
When RF sputtering is used, sputtering is also possible for a ceramic target that is an insulator, and the film formation rate can be increased by using magnetron sputtering.

When physical vapor deposition by RF magnetron sputtering is performed, a target to be a material of a ceramic layer is set in a sputtering apparatus, a substrate on which a reflective layer is formed is placed in a chamber, and the inside of the chamber is set to an argon atmosphere. Is reduced to, for example, 0.2 to 1.2 Pa.
Then, high frequency voltage is applied and sputtering is performed for a predetermined time to form a ceramic layer having a predetermined thickness on the main surface of the second hard coat layer.

(E) Formation of coating resin layer After preparing a composition for a coating resin layer by mixing a monomer or polymer, a solvent, a pigment, or the like, which is a raw material of the coating resin layer, the main surface and side surfaces of the reflective layer, the hard coating layer The composition for the coating resin layer is applied to the side surface and the side surface of the substrate, or the substrate, the hard coat layer, and the reflective layer are dipped in the composition for the coating resin layer, A layer is formed, dried, and then cured to form a coating resin layer.

The mirror of the first aspect of the present invention can be used for applications that require ultraviolet resistance and wear resistance. For example, mirrors for automobiles, aircraft, ships, railways, bicycles, two-wheeled vehicles, etc. It can be used for purposes such as mirroring (condensing). The same applies to the use of the mirror of the second invention described below.

The mirror of the present invention may have a configuration other than the configuration described above. The mirror of the second aspect of the present invention will be described below.
The mirror of the second aspect of the present invention includes a base, a first hard coat layer and a reflective layer sequentially formed on the first main surface side of the base, side surfaces of the first hard coat layer, and main surfaces and side surfaces of the reflective layer. And a coating resin layer that covers the side surface of the substrate, and a second hard coat layer and a ceramic layer that are sequentially formed on the second main surface side facing the first main surface of the substrate. The layer covers the main surface and the side surface of the second hard coat layer and covers a part of the side surface of the substrate.
The ceramic layer may be formed so as to cover the main surface and the side surface of the second hard coat layer and to cover the entire side surface of the substrate.
In the above example, the ceramic layer covers the main surface and the side surface of the second hard coat layer and is formed to cover a part of the side surface of the substrate, and has the same configuration as the mirror of the first invention. Has been.

The shape, structure, etc. of the above-described mirror of the second aspect of the present invention will be further described in detail.
FIG. 2 is a cross-sectional view schematically showing an example of the mirror of the second aspect of the present invention.
The mirror 20 shown in FIG. 2 includes a base 21, a first hard coat layer 22 and a reflective layer 23 that are sequentially formed on the first main surface 21 a side of the base 21, a side 22 b of the first hard coat layer 22, and a reflective surface. The covering resin layer 24 covers the main surface 23a and the side surface 23b of the layer 23, and further covers the side surface 21c of the base body 21, and is formed on the second main surface 21b side facing the first main surface 21a of the base body 21 sequentially. The ceramic layer 26 includes the second hard coat layer 25 and the ceramic layer 26. The ceramic layer 26 covers the main surface 25a and the side surface 25b of the second hard coat layer 25 and covers a part of the side surface 21b of the base 21. Has been.
The reflective layer 23 is formed on the main surface 22 a of the first hard coat layer 22.

In the mirror of the second invention, the ceramic layer covers the main surface and side surfaces of the second hard coat layer and covers part of the side surface of the substrate. It is configured in the same way. The ceramic layer may cover a part of the side surface of the substrate and may cover a part of the side surface of the coating resin layer. The coating resin layer covers a part of the side surface of the substrate and the side surface of the ceramic layer. You may cover a part of.
The substrate, the first hard coat layer, the reflective layer, the coating resin layer, and the second hard coat layer of the second invention are configured in the same manner as the mirror of the first invention. Since the above-described layer forming method, which is a part of the manufacturing method, is the same as the case of the mirror of the first aspect of the present invention, detailed description of the above-described layer and the forming method will be omitted.

Since the material, characteristics, etc. of the ceramic layer constituting the mirror of the second invention are the same as those of the ceramic layer constituting the mirror of the first invention, description thereof will be omitted.
In the mirror of the second aspect of the present invention, the thickness of the ceramic layer is preferably 10 to 500 nm, and more preferably 10 to 200 nm.
When the thickness of the ceramic layer is in the above range and the ceramic layer covers the surface of the second hard coat layer and covers the side surface of the second hard coat layer and at least a part of the side surface of the substrate, The layer and the substrate are sufficiently protected, and sufficient wear resistance is imparted. In addition, it is possible to prevent moisture or the like from entering from the side surface of the substrate and deteriorating the surface of the substrate or the hard coat layer.

When the thickness of the ceramic layer is less than 10 nm, the thickness of the ceramic layer is too thin, so that the mechanical properties and durability are insufficient. Even if the thickness of the ceramic layer exceeds 500 nm, there is no significant change in the characteristics, and it is difficult to form a ceramic layer with such a thickness, and it takes time. It will be something.

The method for forming the ceramic layer in the second aspect of the present invention is substantially the same as the method for forming the ceramic layer in the first aspect of the present invention. However, during sputtering, the ceramic layer forms the main surface and side surfaces of the second hard coat layer. Since it is necessary to cover and to cover part of the side surface of the substrate, it is desirable to set the size of the target larger than in the case of the first aspect of the present invention.

In the mirror of the first invention and the mirror of the second invention, the coating resin layer is not necessarily formed, and the coating resin layer may not be provided. In addition, simply referring to the mirror of the present invention means an invention including both the mirror of the first invention and the mirror of the second invention.

The effects of the mirror of the present invention are listed below.
(1) The mirror of the present invention is configured to reflect the light that has passed through the inside of the substrate by the reflection layer, as in the case of a normal mirror, but hard coat layers are formed on both main surfaces of the substrate. Therefore, it is possible to prevent the surface of the substrate from being damaged.

(2) In the mirror of the present invention, there is almost no difference in the thickness of the two hard coat layers formed on both sides of the substrate as shown in the above formula (1). Warpage can be prevented from occurring.

(3) If the reflective layer is formed directly on the first main surface side of the substrate, the substrate may be deteriorated by the environment at the time of forming the reflective layer, for example, the temperature. Since the reflective layer is formed on the first main surface side via the first hard coat layer, there is no possibility that the substrate is deteriorated by the reflective layer.

(4) In the mirror of the present invention, the outermost layer on the second main surface side is formed with a ceramic layer having higher wear resistance and mechanical properties. Have sex.

(Example)
Examples in which the present invention is disclosed more specifically are shown below. In addition, this invention is not limited only to these Examples.

Example 1
A liquid composition containing a silicone resin is prepared as a hard coat layer composition. First, a flow coat is applied to the first main surface of a mirror-finished acrylic resin substrate having a thickness of 2 mm, a length of 300 mm, and a width of 300 mm. A film was formed by the method, dried, and then cured by thermal curing to form a first hard coat layer having a thickness of 5 μm.

Next, a second hard coat layer having a thickness of 5 μm was formed on the second main surface of the substrate using the same method.

Next, the substrate on which the first hard coat layer and the second hard coat layer are formed on both sides is carried into a sputtering apparatus, evacuated to 1 × 10 ⁻⁵ Pa, using a DC power source at 200 W and 120 nm. A thick Ag film (reflection layer) was formed on the main surface of the first hard coat layer.

Furthermore, a SiC film (ceramic layer) having a thickness of 20 nm was formed using an SiC target at 500 W using an RF power source. When forming the SiC film, a large target is used, and the SiC film (ceramic layer) covers the main surface and side surfaces of the second hard coat layer (the entire second hard coat layer), and one side surface of the substrate. A SiC film (ceramic layer) was formed so as to cover the part.

Next, carbon black is added to the base on which the first hard coat layer and the reflective layer are sequentially formed on the first main surface side, and the second hard coat layer and the ceramic layer are sequentially formed on the second main surface side. The first hard layer is sequentially formed on the first main surface side of the substrate by dipping into a liquid composition for forming a coating resin layer containing an epoxy resin, lifting, drying, heating and curing. The coating resin layer covering the entire periphery including the side surfaces of the coat layer and the reflective layer and covering the side surface of the substrate not covered with the ceramic layer was formed, and the manufacture of the mirror was completed.

In the mirror manufactured by the above method, the first hard coat layer and the reflective layer are sequentially formed on the first main surface side of the substrate, and the second hard coat layer and the ceramic layer are sequentially formed on the second main surface side of the substrate. Has been. The covering resin layer covers the entire periphery including the side surfaces of the first hard coat layer and the reflective layer, and covers the side surface of the substrate not covered with the ceramic layer. The ceramic layer is formed of the second hard coat layer. The main surface and the side surface (the entire second hard coat layer) are covered, and a part of the side surface of the substrate is covered. The thickness of each layer was measured using a laser microscope.

10, 20 Mirror 11, 21 Base 11a, 21a First main surface 11b, 21b Second main surface of the base
11c, 21c Side surfaces 12, 22 of the first hard coat layer 12a, 22a Main surfaces 12b, 22b of the first hard coat layer Side surfaces 13, 23 of the first hard coat layer Reflective layers 13a, 23a Main surface 13b of the reflective layer, 23b Side surfaces 14 and 24 of the reflective layer 15 Coating resin layers 15 and 25 Second hard coat layers 15a and 25a Main surfaces 15b and 25b of the second hard coat layer Side surfaces 16 and 26 of the second hard coat layer Ceramic layer

Claims (10)

A resin base, a first hard coat layer and a reflective layer sequentially formed on the first main surface side of the base, and a second main surface side facing the first main surface of the base sequentially A mirror composed of a second hard coat layer and a ceramic layer formed, and configured to reflect the light that has passed through the inside of the substrate by the reflective layer;
A mirror characterized in that a difference in thickness between the first hard coat layer and the second hard coat layer formed on both main surfaces of the substrate is expressed by the following equation (1).
−3 ≦ [(thickness of first hard coat layer−thickness of second hard coat layer) / thickness of first hard coat layer] × 100 ≦ 3 (1) The mirror according to claim 1, wherein the first hard coat layer and the second hard coat layer are made of a silicone resin, an acrylic resin, or a silica hybrid composite. 3. The mirror according to claim 1, wherein the ceramic layer covers a surface of the second hard coat layer and covers a side surface of the second hard coat layer and at least a part of a side surface of the substrate. The entire periphery including the side surfaces of the first hard coat layer and the reflective layer, which are sequentially formed on the first main surface side of the substrate, is covered with a coating resin layer, and at least one of the side surfaces of the substrate. The mirror according to claim 1, wherein the part is also covered with the coating resin layer. The ceramic layer is made of SiC, WC, TiC, TaC, ZrC, VC, HfC, B ₄ C, Mo ₂ C, NbC, Cr ₃ C ₂ , Si ₃ N ₄ , TiN, AlN, BN, ZrN, TaN, NbN. The mirror according to claim 1, which is a ceramic layer made of at least one selected from the group consisting of Cr ₂ N, VN, and HfN. The said hard-coat layer is a mirror in any one of Claims 1-5 containing a translucent filler. The mirror according to claim 5 or 6, wherein the ceramic layer is made of SiC. The mirror according to claim 1, wherein the hard coat layer has a thickness of 1 to 10 μm. The mirror according to claim 1, wherein the ceramic layer has a thickness of 10 to 500 nm. The mirror according to claim 1, wherein the reflective layer is made of at least one selected from the group consisting of Ag, Au, Al, Cr, Ni, and Pt.

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