JP2021024251A - Electromagnetic wave transmissible laminate - Google Patents

Abstract

To provide an electromagnetic wave transmissible laminate simultaneously realizing electromagnetic wave transmission properties and high brightness and capable of achieving an excellent metal appearance.SOLUTION: An electromagnetic wave transmissible laminate 1 includes a substrate 10 and a metallic luster layer 12 and a resin layer 13 formed on the substrate, in which a reflection rate Y is 1 to 60% in an SCE measurement of a CIE-XYZ colorimetric system of reflected light within a range of a wavelength 380 to 780 nm. Further, the metallic luster layer is a metal layer, and the metal layer includes a plurality of parts in a discontinuous state to each other at least a part.SELECTED DRAWING: Figure 1

Description

The present invention relates to an electromagnetic wave transmitting laminate.

Conventionally, a member having electromagnetic wave transmission and metallic luster has both a high-class appearance derived from the metallic luster and electromagnetic wave transmission, and is therefore suitably used for an apparatus for transmitting and receiving electromagnetic waves.
When metal is used for the metallic luster member, the transmission and reception of electromagnetic waves is substantially impossible or disturbed. Therefore, in order not to interfere with the transmission and reception of electromagnetic waves and not to impair the design, an electromagnetic wave transmitting laminate having both metallic luster and electromagnetic wave transmission is required.

Such an electromagnetic wave transmissive laminate is used as a device for transmitting and receiving electromagnetic waves to various devices that require communication, for example, an automobile door handle provided with a smart key, an in-vehicle communication device, a mobile phone, a personal computer, and other electronic devices. It is expected to be applied to such applications. Furthermore, in recent years, with the development of IoT technology, it is expected to be applied in a wide range of fields such as home appliances such as refrigerators and household appliances, which have not been used for communication in the past.
From the viewpoint of design, these electromagnetic wave-transmitting laminates may be required to have a matte texture having a metallic luster and suppressing brilliance.

Regarding the electromagnetic wave transmitting laminate, Patent Document 1 discloses a resin product containing a metal film made of chromium (Cr) or indium (In). This resin product has a resin base material, an inorganic base film containing an inorganic compound formed on the resin base material, and a brilliant film formed on the inorganic base film by a physical vapor deposition method. It contains a metal film made of chromium (Cr) or indium (In) having a continuous structure.
On the other hand, as an electromagnetic wave transmissive laminate having no electromagnetic wave transmissivity, Patent Document 2 describes a metal layer having high reflectivity and diffusivity and excellent reflection efficiency in light reflection against low-angle incident light. A light-reflecting laminate composed of a light-reflecting body or a white-reflecting film containing the above and a light-diffusing layer is described.

JP-A-2007-144988 International Publication No. 2009/139402

However, it is difficult to control the brilliance of the metal film in the prior art, and it is difficult to provide a laminate having an excellent metallic appearance, which exhibits excellent electromagnetic wave transmission, has a metallic luster, and suppresses the brilliance. there were.
The present invention has been made to solve these problems in the prior art, and provides an electromagnetic wave-transmitting laminate having an excellent metallic appearance, which has excellent electromagnetic wave transmission, has metallic luster, and suppresses brilliance. The purpose is to provide.

As a result of diligent studies to solve the above problems, the present inventors have provided a metallic luster layer and reflected the reflected light in the wavelength range of 380 nm to 780 nm in the SCE measurement of the CIE-XYZ color system. We have found that by setting the rate Y to 1 to 60%, an electromagnetic wave-transmitting laminate having an excellent metallic appearance, which has excellent electromagnetic wave transmission, has metallic luster, and suppresses brilliance can be obtained. It came to be completed.

[1]
A substrate, a metallic luster layer formed on the substrate, and a resin layer are provided.
An electromagnetic wave transmissive laminate having a reflectance Y of 1 to 60% in SCE measurement of the CIE-XYZ color system of reflected light in the wavelength range of 380 nm to 780 nm.
[2]
The metallic luster layer is a metal layer,
The electromagnetic wave transmitting laminate according to [1], wherein the metal layer includes a plurality of portions that are discontinuous with each other at least in part.
[3]
The electromagnetic wave transmitting laminate according to [2], wherein the metal layer is a layer containing aluminum or an aluminum alloy.
[4]
The electromagnetic wave transmitting laminate according to any one of [1] to [3], wherein the resin layer contains a layer containing light diffusing fine particles.
[5]
The electromagnetic wave transmitting laminate according to any one of [1] to [4], wherein the resin layer contains a light diffusing pressure-sensitive adhesive layer.
[6]
The electromagnetic wave transmitting laminate according to any one of [1] to [5], further comprising an indium oxide-containing layer between the substrate and the metallic luster layer.
[7]
The electromagnetic wave transmitting laminate according to [6], wherein the indium oxide-containing layer is provided in a continuous state.
[8]
The electromagnetic wave transmittance according to [6] or [7], wherein the indium oxide-containing layer contains _{any one of indium oxide (In 2} O ₃ ), indium tin oxide (ITO), or indium zinc oxide (IZO). Laminated body.
[9]
The electromagnetic wave transmitting laminate according to any one of [6] to [8], wherein the thickness of the indium oxide-containing layer is 1 nm to 1000 nm.
[10]
The electromagnetic wave transmissive laminate according to any one of [6] to [9], wherein the thickness of the metallic luster layer is 5 nm to 100 nm.
[11]
The ratio of the thickness of the metallic luster layer to the thickness of the indium oxide-containing layer (thickness of the metallic luster layer / thickness of the indium oxide-containing layer) is 0.02 to 100 [6] to [10]. ], The electromagnetic wave transmissive laminate according to any one of the items.
[12]
The electromagnetic wave transmissive laminate according to any one of [1] to [11], which has a sheet resistance of 100 Ω / □ or more.
[13]
The electromagnetic wave transmitting laminate according to [2], wherein the plurality of portions are formed in an island shape.
[14]
The electromagnetic wave transmissive laminate according to any one of [1] to [13], wherein the substrate is a substrate film, a resin molded substrate, a glass substrate, or an article to which metallic luster should be imparted. body.

According to the present invention, it is possible to provide an electromagnetic wave transmitting laminate having an excellent metallic appearance, having excellent electromagnetic wave transmission, having a metallic luster, and suppressing brilliance.

FIG. 1 is a schematic cross-sectional view of an electromagnetic wave transmitting laminated body according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an electromagnetic wave transmitting laminated body according to an embodiment of the present invention. FIG. 3 is a schematic cross-sectional view of an electromagnetic wave transmitting laminated body according to an embodiment of the present invention. FIG. 4 is a schematic cross-sectional view of an electromagnetic wave transmitting laminated body according to an embodiment of the present invention. FIG. 5 is an electron micrograph of the surface of the electromagnetic wave transmitting laminate according to the embodiment of the present invention. FIG. 6 is a diagram for explaining a method of measuring the film thickness of the metal layer of the electromagnetic wave transmitting laminate according to the embodiment of the present invention. FIG. 7 is a diagram showing a transmission electron micrograph (TEM image) of a cross section of a metal layer according to an embodiment of the present invention.

Hereinafter, one preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following, for convenience of explanation, only preferred embodiments of the present invention will be shown, but of course, this is not intended to limit the present invention.

<1. Basic configuration>
The electromagnetic wave transmitting laminate according to the embodiment of the present invention includes a substrate, a metallic luster layer formed on the substrate, and a resin layer, and has a CIE-XYZ table of reflected light in a wavelength range of 380 nm to 780 nm. The reflectance Y in the SCE measurement of the color system is 1 to 60%.
The metallic luster layer is preferably a metal layer, and the metal layer includes a plurality of portions that are discontinuous with each other at least in part.
Hereinafter, the case where the metallic luster layer is a metal layer may be described, but the present invention is not limited to the following description.
1 to 4 show schematic cross-sectional views of the electromagnetic wave transmitting laminated body 1 according to the embodiment of the present invention. Further, FIG. 5 shows an electron micrograph (SEM image) of the surface of the metal layer of the electromagnetic wave transmitting laminate in order to explain the discontinuous structure of the metal layer. Further, FIG. 7 shows a transmission electron micrograph (TEM image) of a cross-sectional view of the metal layer 12 having an island-like structure according to the embodiment of the present invention.

As shown in FIG. 1, the electromagnetic wave transmitting laminate 1 includes a substrate 10, a metallic luster layer (metal layer 12) formed on the substrate 10, and a resin layer 13.

The metal layer 12 is formed on the substrate 10. The metal layer 12 includes a plurality of portions 12a. These plurality of portions 12a in the metal layer 12 are separated from each other by a gap 12b at least in a discontinuous state, that is, in at least a part. Since they are separated by the gap 12b, the sheet resistance of these plurality of portions 12a becomes large, and the interaction with the radio wave decreases, so that the radio wave can be transmitted. Each of these portions 12a may be an aggregate of sputtered particles formed by vapor deposition, sputtering, or the like of a metal.

The "discontinuous state" as used herein means a state in which they are separated from each other by a gap 12b, and as a result, they are electrically insulated from each other. By being electrically insulated, the sheet resistance becomes large, and the desired electromagnetic wave transmission can be obtained. That is, according to the metal layer 12 formed in a discontinuous state, sufficient brilliance can be easily obtained, and electromagnetic wave transmission can be ensured. The discontinuous form is not particularly limited, and includes, for example, an island-like structure, a crack structure, and the like. Here, as shown in FIG. 5, the “island-like structure” means that the metal particles are independent of each other, and the metal particles are spread so as to be slightly separated from each other or partially in contact with each other. Means the structure.

The crack structure is a structure in which a metal thin film is divided by cracks.
The metal layer 12 having a crack structure can be formed, for example, by providing a metal thin film layer on a base film and bending and stretching it to generate cracks in the metal thin film layer. At this time, the metal layer 12 having a crack structure can be easily formed by providing a brittle layer made of a material having poor elasticity, that is, easily forming cracks by stretching, between the base film and the metal thin film layer. ..

As described above, the mode in which the metal layer 12 is discontinuous is not particularly limited, but from the viewpoint of productivity, an island-shaped structure is preferable.

The electromagnetic wave transmissive laminate 1 according to the present embodiment has a reflectance Y of 1 to 60% of the reflected light in the wavelength range of 380 nm to 780 nm in the SCE (specular reflection light removal) measurement of the CIE-XYZ color system. .. By setting the reflectance Y in this range, an electromagnetic wave transmissive laminate having an excellent metallic appearance and having a metallic luster and suppressed brilliance can be obtained. The reflectance Y represents the visual reflectance, and when the reflectance Y is 1% or more, the brilliance can be suppressed. The reflectance Y is more preferably 10% or more, and further preferably 20% or more.
The reflectance Y can be measured by a measuring device such as a spectrocolorimeter CM-2600d manufactured by Konica Minolta Co., Ltd. using D65 as a standard light source, and can be measured by the method described in Examples.

The electromagnetic wave transmittance of the electromagnetic wave transmissive laminate 1 can be evaluated by, for example, the amount of radio wave transmission attenuation.
It should be noted that there is a correlation between the amount of electromagnetic wave transmission attenuation in the microwave band (5 GHz) and the amount of electromagnetic wave transmission attenuation in the frequency band (76 to 80 GHz) of the millimeter wave radar, and the values are relatively close to each other. The electromagnetic wave transmissive laminate having excellent electromagnetic wave transmission in the wave band is also excellent in electromagnetic wave transmission in the frequency band of the millimeter wave radar.
The amount of radio wave transmission attenuation in the microwave band (5 GHz) is preferably 10 [−dB] or less, more preferably 5 [−dB] or less, and further preferably 2 [−dB] or less. .. If it is larger than 10 [−dB], there is a problem that 90% or more of the radio waves are blocked.

The sheet resistance of the electromagnetic wave transmissive laminate 1 also has a correlation with the electromagnetic wave transmissivity.
The sheet resistance of the electromagnetic wave transmitting laminated body 1 is preferably 100Ω / □ or more, and in this case, the amount of radio wave transmission attenuation in the microwave band (5 GHz) is about 10 to 0.01 [−dB].
The sheet resistance of the electromagnetic wave transmitting laminated body 1 is more preferably 200 Ω / □ or more, further preferably 600 Ω / □ or more, and particularly preferably 1000 Ω / □ or more.
The sheet resistance of the electromagnetic wave transmitting laminated body 1 can be measured by an eddy current measuring method according to JIS-Z2316-1: 2014.

The amount of radio wave transmission attenuation and sheet resistance of the electromagnetic wave transmission laminate 1 are affected by the material and thickness of the metallic luster layer.
Further, when the electromagnetic wave transmitting laminate 1 includes the indium oxide-containing layer 11, it is also affected by the material and thickness of the indium oxide-containing layer 11.

<2. Hypokeimenon>
Examples of the substrate 10 include resins, glasses, ceramics, and the like from the viewpoint of electromagnetic wave transmission.
The substrate 10 may be a substrate film, a resin molded substrate, a glass substrate, or an article to which metallic luster should be imparted.
More specifically, as the base film, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene. , Polypropylene (PP), polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), ABS and other homopolymers and copolymers can be used.

According to these members, the brilliance and the electromagnetic wave transmission are not affected. However, from the viewpoint of forming the indium oxide-containing layer 11 and the metallic glossy layer later, it is preferable that the layer can withstand high temperatures such as vapor deposition and sputtering. Therefore, among the above materials, for example, polyethylene terephthalate, polyethylene naphthalate, etc. Acrylic, polycarbonate, cycloolefin polymer, ABS, polypropylene and polyurethane are preferred. Of these, polyethylene terephthalate, cycloolefin polymer, polycarbonate, and acrylic are preferable because they have a good balance between heat resistance and cost.

The base film may be a single-layer film or a laminated film. From the viewpoint of ease of processing and the like, the thickness is preferably about 6 μm to 250 μm, for example. In order to strengthen the adhesive force with the indium oxide-containing layer 11 and the metallic luster layer, plasma treatment or easy-adhesion treatment may be performed. Moreover, it is preferable that it does not contain particles.
When the substrate 10 is a base film, the metallic luster layer may be provided on at least a part of the base film, may be provided on only one side of the base film, or may be provided on both sides.

It should be noted here that the base film is only an example of an object (base 10) capable of forming a metallic luster layer on its surface. As described above, the substrate 10 includes, as described above, a resin molded substrate, a glass substrate, and the article itself to which metallic luster should be imparted. Examples of resin molded base materials and articles to which metallic luster should be imparted include vehicle structural parts, vehicle-mounted products, electronic device housings, home appliance housings, structural parts, mechanical parts, and various automobiles. Examples include parts for household appliances such as parts for electronic devices, furniture, kitchen utensils, medical equipment, parts for building materials, other structural parts and exterior parts.

The metallic luster layer can be formed on all of these substrates, and may be formed on a part of the surface of the substrate or on all of the surfaces of the substrate. In this case, the substrate 10 to which the metallic luster layer is to be provided preferably satisfies the same materials and conditions as the above-mentioned substrate film.

<3. Indium oxide-containing layer>
Further, as shown in FIG. 2, the electromagnetic wave transmissive laminate 1 according to the embodiment may further include an indium oxide-containing layer 11 between the substrate 10 and the metallic luster layer (metal layer 12). The indium oxide-containing layer 11 may be provided directly on the surface of the substrate 10, or may be indirectly provided via a protective film or the like provided on the surface of the substrate 10. The indium oxide-containing layer 11 is preferably provided continuously on the surface of the substrate 10 to be imparted metallic luster, in other words, without gaps. By providing the indium oxide-containing layer 11 in a continuous state, the smoothness and corrosion resistance of the indium oxide-containing layer 11, the metal layer 12, and the electromagnetic wave-transmitting laminate 1 can be improved, and the indium oxide-containing layer 11 can be provided without in-plane variation. It also facilitates film formation.

As described above, the indium oxide-containing layer 11 is further provided between the substrate 10 and the metal layer 12, that is, the indium oxide-containing layer 11 is formed on the substrate 10 and the metal layer 12 is formed on the indium oxide-containing layer 11. According to the above, the metal layer 12 is easily formed in a discontinuous state, which is preferable. The details of the mechanism are not always clear, but when sputtered particles by metal deposition or sputtering form a thin film on the substrate, the surface diffusivity of the particles on the substrate affects the shape of the thin film, and the substrate It is considered that the higher the temperature, the smaller the wettability of the metal layer with respect to the substrate, and the lower the melting point of the material of the metal layer, the easier it is to form a discontinuous structure. Then, it is considered that by providing the indium oxide-containing layer on the substrate, the surface diffusibility of the metal particles on the surface thereof is promoted, and the metal layer can be easily grown in a discontinuous state.

_{Indium oxide (In 2} O ₃ ) itself can be used as the indium oxide-containing layer 11, or a metal-containing substance such as indium tin oxide (ITO) or indium zinc oxide (IZO) is used. You can also do it. However, ITO and IZO containing a second metal are more preferable because they have high discharge stability in the sputtering process. By using these indium oxide-containing layers 11, a continuous film can be formed along the surface of the substrate, and in this case, a metal layer laminated on the indium oxide-containing layer can be formed. For example, it is preferable because it tends to have an island-like discontinuous structure. Further, as will be described later, in this case, not only chromium (Cr) or indium (In) but also aluminum or the like, which is usually difficult to form a discontinuous structure in the metal layer and is difficult to apply to this application, is used. It becomes easier to include various metals.

The content rate (content rate = (SnO ₂ / (In ₂ O ₃ + SnO ₂ )) × 100), which is the mass ratio of tin oxide (SnО ₂ ) contained in ITO, is not particularly limited, but for example, It is 2.5% by mass to 30% by mass, more preferably 3% by mass to 10% by mass. _{Further, the content rate (content rate = (ZnO / (In 2} O ₃ + ZnO)) × 100), which is the mass-weight ratio of zinc oxide (ZnO) contained in IZO, is, for example, 2% by mass to 20% by mass. ..
The thickness of the indium oxide-containing layer 11 is usually preferably 1000 nm or less, more preferably 50 nm or less, still more preferably 20 nm or less, from the viewpoint of sheet resistance, electromagnetic wave transmission, and productivity. On the other hand, in order to facilitate the discontinuous state of the laminated metal layer 12, it is preferably 1 nm or more, and in order to ensure the discontinuous state, it is more preferably 2 nm or more, and 5 nm or more. Is more preferable.

<4. Metallic luster layer>
The metallic luster layer is formed on the substrate 10. The metallic luster layer is a layer having a metallic appearance, and is preferably a layer having a metallic luster. The material for forming the metallic luster layer is not particularly limited, and may contain a metal or a resin, or may contain a metal and a resin.
When the metallic luster layer is made of only resin, metallic luster can be obtained by laminating resins having different refractive indexes.
The thickness of the metallic luster layer is usually preferably 5 nm or more so as to exhibit sufficient metallic luster, while it is usually preferably 100 nm or less from the viewpoint of sheet resistance and electromagnetic wave transmission. For example, 7 nm to 100 nm is more preferable, and 10 nm to 70 nm is further preferable. This thickness is also suitable for forming a uniform film with good productivity, and the appearance of the final resin molded product is also good.
The metallic luster layer is preferably a metal layer, and the metal layer preferably includes a plurality of portions that are discontinuous with each other at least in part.

(Metal layer)
The metal layer 12 is formed on the substrate and includes a plurality of portions that are discontinuous with each other at least in part.
When the metal layer 12 is in a continuous state on the substrate, a sufficient metallic luster can be obtained, but the amount of radio wave transmission attenuation becomes very large, and therefore electromagnetic wave transmission cannot be ensured.

The details of the mechanism by which the metal layer 12 becomes discontinuous on the substrate are not always clear, but it is presumed to be roughly as follows. That is, in the thin film forming process of the metal layer 12, the ease of forming the discontinuous structure is related to the surface diffusion on the substrate to which the metal layer 12 is applied, the temperature of the substrate is high, and the metal layer with respect to the substrate is formed. The smaller the wettability of the metal layer and the lower the melting point of the metal layer material, the easier it is to form a discontinuous structure. Therefore, with respect to metals other than aluminum (Al) particularly used in the following examples, metals having a relatively low melting point such as zinc (Zn), lead (Pb), copper (Cu), and silver (Ag) are used. , It is considered that a discontinuous structure can be formed by the same method.

It is desirable that the metal layer 12 has a relatively low melting point as well as being able to exhibit sufficient brilliance. This is because the metal layer 12 is preferably formed by thin film growth using sputtering. For this reason, a metal having a melting point of about 1000 ° C. or lower is suitable as the metal layer 12, and for example, aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), and silver (Ag). ), And any of an alloy containing the metal as a main component is preferably contained. In particular, it is preferable to contain Al or an alloy thereof for the reason of brilliance, stability, price and the like of the substance, and Al and its alloy are more preferable. When an aluminum alloy is used, the aluminum content is preferably 50% by mass or more.

The equivalent circle diameter of the portion 12a of the metal layer 12 is not particularly limited, but is usually about 10 to 1000 nm. The average particle diameter of the plurality of portions 12a means the average value of the equivalent circle diameters of the plurality of portions 12a.
The circle-equivalent diameter of the portion 12a is the diameter of a perfect circle corresponding to the area of the portion 12a.
The distance between the portions 12a is not particularly limited, but is usually about 10 to 1000 nm.

The thickness of the metal layer 12 is usually preferably 5 nm or more so as to exhibit sufficient metallic luster, while it is usually preferably 100 nm or less from the viewpoint of sheet resistance and electromagnetic wave transmission. For example, 10 nm to 100 nm is preferable, and 15 nm to 70 nm is more preferable. This thickness is also suitable for forming a uniform film with good productivity, and the appearance of the final resin molded product is also good.

For the same reason, the ratio of the thickness of the metallic luster layer to the thickness of the indium oxide-containing layer (thickness of the metallic luster layer / thickness of the indium oxide-containing layer) is preferably in the range of 0.02 to 100. The range of 0.1 to 100 is more preferable, and the range of 0.3 to 35 is even more preferable.

The sheet resistance of the metallic luster layer is preferably 100 Ω / □ or more. In this case, the electromagnetic wave transmission property is about 10 to 0.01 [−dB] at a wavelength of 5 GHz. More preferably, it is 1000 Ω / □ or more.

When the indium oxide-containing layer is further provided, the sheet resistance of the metallic luster layer and the indium oxide-containing layer as a laminate is preferably 100 Ω / □ or more. In this case, the electromagnetic wave transmission property is about 10 to 0.01 [−dB] at a wavelength of 5 GHz. More preferably, it is 1000 Ω / □ or more. The value of this sheet resistance is greatly affected not only by the material and thickness of the metallic luster layer but also by the material and thickness of the indium oxide-containing layer which is the base layer. Therefore, when the indium oxide-containing layer is provided, it is necessary to consider the relationship with the indium oxide-containing layer.

<5. Barrier layer>
As shown in FIG. 4, the electromagnetic wave transmitting laminate 1 may have a barrier layer 14 on a surface of the metallic luster layer (metal layer 12) opposite to the substrate 10 side. The barrier layer 14 may be laminated on the metal layer 12, and the gap 12b does not necessarily have to be completely filled.
The barrier layer 14 is a layer for suppressing oxidation (corrosion) of the metal layer 12. The barrier layer preferably contains at least one selected from the group consisting of at least one oxide of metal and metalloid, nitrides, carbides, oxynitrides, carbides, carbides and carbides. As the metal, for example, aluminum, titanium, indium, magnesium and the like can be used, and as the metalloid, for example, silicon, bismuth, germanium and the like can be used.
Specifically, for example, ZnO + Al ₂ O ₃ (AZO), indium zinc oxide (IZO), indium tin oxide (ITO), silicon nitride silicon nitride film (SiOCN), silicon nitride film (SiON), silicon nitride film (SiN). ), SiO _X , AlO _X , AlON, TiO _{X and the} like can be used.
In order to improve the ability of the barrier layer 14 to suppress oxidation (corrosion) of the metal layer 12 (hereinafter, also referred to as "barrier property"), the network structure (mesh-like structure) in the barrier layer is made dense. It preferably contains carbon and nitrogen. In order to further improve the transparency, it is preferable that oxygen is contained. That is, the barrier layer preferably contains at least one carbide oxide of metal and metalloid.

Further, in order to improve the barrier property, it is preferable that the barrier layer does not easily allow water vapor to permeate. The degree of water vapor permeation of the barrier layer can be evaluated by various methods, and for example, it can be evaluated using the amount of water vapor permeation measured by the method described in the column of Examples. For the barrier properties improve, it is preferable that the water vapor permeation amount is less than 3g ^/ m 2 · day, more preferably at most ^{1g / m 2 · day, 0.5g} / m 2 · day or less Is more preferable.

The thickness of the barrier layer 14 is not particularly limited, but is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more in order to improve the barrier property. Further, in order to improve the electromagnetic wave transmission and the metallic luster of the appearance, 100 nm or less is preferable, 70 nm or less is more preferable, and 50 nm or less is further preferable.

Further, in order to further suppress the oxidation (corrosion) of the metal layer 12, the barrier layer may be further provided between the metal layer and the substrate.
When the electromagnetic wave transmissive laminate 1 includes an indium oxide-containing layer, a barrier layer may be provided between the indium oxide-containing layer and the metal layer, and a barrier layer is provided on the side opposite to the metal layer of the indium oxide-containing layer. You may. Moreover, it may be provided in both of them.

Further, the electromagnetic wave transmitting laminate may be provided with other layers depending on the application, in addition to the above-mentioned metal layer, indium oxide-containing layer, and barrier layer.
Other layers include an optical adjustment layer (color adjustment layer) such as a high-refractive material for adjusting the appearance such as color, and a protective layer (scratch resistance layer) for improving durability such as scratch resistance. , Easy-adhesion layer, hard coat layer, antireflection layer, light extraction layer, anti-glare layer and the like.

<6. Resin layer>
The electromagnetic wave transmitting laminate of the present embodiment includes a resin layer 13. As shown in FIG. 1, the resin layer 13 is preferably formed on the metallic luster layer.
The resin layer 13 is an optical adjustment layer (color adjustment layer) such as a high-refractive material for adjusting the appearance such as color, and a protective layer (scratch resistance) for improving durability such as moisture resistance and scratch resistance. It may be a sex layer), an easy-adhesion layer, an adhesive layer, a hard coat layer, an antireflection layer, a light extraction layer, an anti-glare layer, or the like.
A plurality of resin layers 13 can be provided, and it is preferable that at least one layer is a layer having light diffusivity. When the resin layer 13 is a layer having light diffusivity, the light diffusive fine particles diffuse light, so that the reflected light from the metallic luster layer is diffused, and the reflectance Y in the SCE measurement of the CIE-XYZ color system is set to 1. It becomes easy to set it to ~ 60%. The layer having light diffusivity is preferably a layer containing light diffusible fine particles.

For example, when the resin layer 13 is a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer may be a light-diffusing pressure-sensitive adhesive layer containing light-diffusing fine particles. In addition to the pressure-sensitive adhesive layer, the electromagnetic wave-transmitting laminate may be provided with another resin layer depending on the intended use, and the other resin layer may be a layer having light diffusivity.

FIG. 3 is a schematic cross-sectional view of an electromagnetic wave transmitting laminated body according to an embodiment of the present invention. As shown in FIG. 3, the electromagnetic wave transmitting laminate 1 may include a substrate 10, an indium oxide-containing layer 11, a metal layer 12, and a light diffusing adhesive layer 13a and a hard coat layer 13b as resin layers. Good. In the electromagnetic wave transmitting laminate 1 of the present embodiment, an indium oxide-containing layer 11, a metal layer 12, and a light diffusing pressure-sensitive adhesive layer 13a are provided on a substrate 10 provided with a hard coat layer 13b.

The electromagnetic wave transmitting laminated body 1 of the present embodiment may be used by being attached to an adherend member via a light diffusing pressure-sensitive adhesive layer 13a. For example, the adherend member can be decorated from the inside by attaching the electromagnetic wave transmissive laminate 1 to the transparent adherend member via the light diffusing adhesive layer 13a.
The electromagnetic wave transmitting laminated body 1 is interposed via the light diffusing adhesive layer 13a with respect to the surface of the transparent adherend member on the side opposite to the visible side (hereinafter, also referred to as the outside) (hereinafter, also referred to as the inside). The light diffusing adhesive layer 13a and the metal layer 12 are visually recognized through the adherend member. Therefore, the electromagnetic wave transmissive laminate 1 of the present embodiment has high light diffusivity, and can obtain an excellent metallic appearance that exhibits metallic luster and suppresses brilliance. As the transparent adherend member, for example, a member made of glass or plastic can be used, but the transparent member is not limited to this.

The haze value of the resin layer is preferably 10% or more, more preferably 20% or more, still more preferably 50% or more from the viewpoint of realizing a matte appearance. By setting the haze value of the resin layer to 10% or more, it becomes easy to set the reflectance Y in a desired range. Further, by adjusting the haze value of the resin layer, it is possible to control ^{the brightness L *} value, the hue a ^* value, and the b ^{* value of the obtained electromagnetic wave transmitting laminate.}
The haze value of the resin layer can be measured by a measuring device such as a spectrocolorimeter CM-2600d manufactured by Konica Minolta Co., Ltd., and can be measured by the method described in Examples.

The ratio of the thickness of the metallic luster layer to the thickness of the resin layer (thickness of the metallic luster layer / thickness of the resin layer) can be changed depending on the type and number of the resin layers, and is not particularly limited, but is bonded. From the viewpoint of step absorption at the time, 0.0001 or more is preferable, 0.0003 or more is more preferable, and 0.001 or more is further preferable. Further, from the viewpoint of thinning the housing, 0.01 or less is preferable, 0.006 or less is more preferable, and 0.003 or less is further preferable. The thickness of the resin layer is the thickness of each resin layer when a plurality of resin layers are provided.
When the light diffusing adhesive layer is provided as the resin layer, the ratio of the thickness of the metallic luster layer to the thickness of the light diffusing adhesive layer (thickness of the metallic luster layer / thickness of the light diffusing adhesive layer) is determined at the time of bonding. From the viewpoint of step absorption, 0.0001 or more is preferable, 0.0003 or more is more preferable, and 0.001 or more is further preferable. Further, from the viewpoint of thinning the housing, 0.01 or less is preferable, 0.006 or less is more preferable, and 0.003 or less is further preferable.

(Light diffusion adhesive layer)
The light diffusing pressure-sensitive adhesive layer containing the light diffusing fine particles can be formed from the base pressure-sensitive adhesive composition and the light diffusing fine particles.
(1-1) Base Adhesive Composition The base adhesive composition preferably contains a (meth) acrylic polymer (A) as the base polymer. The (meth) acrylic polymer (A) preferably contains an alkyl (meth) acrylate (a1) constituting the main skeleton of the (meth) acrylic polymer (A) as a monomer unit. In addition, (meth) acrylate means acrylate and / or methacrylate.

Examples of the alkyl (meth) acrylate (a1) include those having a linear or branched chain-like alkyl group having 1 to 18 carbon atoms. For example, examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, amyl group, hexyl group, cyclohexyl group, heptyl group, 2-ethylhexyl group, isooctyl group, nonyl group and decyl. Examples thereof include a group, an isodecyl group, a dodecyl group, an isomyristyl group, a lauryl group, a tridecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group and the like. These can be used alone or in combination.

The blending ratio of the alkyl (meth) acrylate (a1) is preferably 50% by mass or more, preferably 50 to mass%, based on the total constituent monomers (100% by mass) constituting the (meth) acrylic polymer (A). It is more preferably 100% by mass, further preferably 60 to 100% by mass, and particularly preferably 70 to 90% by mass.

The (meth) acrylic polymer (A) is composed of a group consisting of a carboxyl group-containing monomer (a2), a hydroxyl group-containing monomer (a3), and a nitrogen-containing monomer (a4) for the purpose of improving adhesiveness and heat resistance. It is preferable to include one or more selected monomers as a monomer component.

As the carboxyl group-containing monomer (a2), one having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a carboxyl group can be used without particular limitation. .. Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like. Can be used alone or in combination. These anhydrides can be used for itaconic acid and maleic acid. Among these, acrylic acid and methacrylic acid are preferable, and acrylic acid is particularly preferable.

The blending ratio of the carboxyl group-containing monomer (a2) is preferably 10% by mass or less, preferably 0.05% by mass or less, based on the total constituent monomers (100% by mass) constituting the (meth) acrylic polymer (A). It is more preferably 10% by mass, further preferably 0.1 to 10% by mass, and particularly preferably 0.5 to 5% by mass.

As the hydroxyl group-containing monomer (a3), a monomer having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a hydroxyl group can be used without particular limitation. .. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl ( Hydroxyalkyl (meth) acrylates such as meta) acrylates, 8-hydroxyoctyl (meth) acrylates, 10-hydroxydecyl (meth) acrylates, 12-hydroxylauryl (meth) acrylates; (4-hydroxymethylcyclohexyl) methyl ( Examples thereof include hydroxyalkylcycloalkalane (meth) acrylates such as meta) acrylates. Other examples include hydroxyethyl (meth) acrylamide, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like. These can be used alone or in combination. Among these, hydroxyalkyl (meth) acrylate is preferable, and 2-hydroxyethyl (meth) acrylate is more preferable.

The blending ratio of the hydroxyl group-containing monomer (a3) is preferably 20% by mass or less, preferably 0.05% by mass or less, based on the total constituent monomers (100% by mass) constituting the (meth) acrylic polymer (A). It is more preferably ~ 20% by mass, further preferably 0.1 to 15% by mass, and particularly preferably 1 to 15% by mass.

As the nitrogen-containing monomer (a4), one having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group and having a functional group having a nitrogen atom is used without particular limitation. be able to.

The blending ratio of the nitrogen-containing monomer (a4) is preferably 20% by mass or less, preferably 0.05 to mass%, based on the total constituent monomers (100% by mass) constituting the (meth) acrylic polymer (A). It is more preferably 20% by mass, further preferably 0.1 to 15% by mass, and particularly preferably 1 to 15% by mass.

In addition to the alkyl (meth) acrylate (a1), the carboxyl group-containing monomer (a2), the hydroxyl group-containing monomer (a3), and the nitrogen-containing monomer (a4), the (meth) acrylic polymer (A) is further added. Introduce one or more copolymerized monomers having a polymerizable functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group by copolymerization for the purpose of improving adhesiveness and heat resistance. be able to. Specific examples of such copolymerizable monomers include caprolactone adducts of acrylic acid; containing sulfonic acid groups such as styrene sulfonic acid, allyl sulfonic acid, sulfopropyl (meth) acrylate, and (meth) acryloyloxynaphthalene sulfonic acid. Monomer; Examples thereof include a sulfonic acid group-containing monomer such as 2-hydroxyethylacryloyl phosphate.

The ratio of the copolymerization monomer other than the carboxyl group-containing monomer (a2), the hydroxyl group-containing monomer (a3), and the nitrogen-containing monomer (a4) is not particularly limited, but all of the (meth) acrylic polymer (A) is composed. In the monomer, it is preferably 10% by mass or less, more preferably 0.1 to 10% by mass, still more preferably 0.1 to 5% by mass.

The (meth) acrylic polymer (A) can be obtained by polymerizing the above-mentioned monomers in an appropriate combination according to the purpose and desired properties. The obtained (meth) acrylic polymer (A) may be any of a random copolymer, a block copolymer, and a graft copolymer. The (meth) acrylic polymer (A) can be synthesized by any appropriate method. For example, it can be synthesized by referring to "Adhesive / Adhesive Chemistry and Applications" by Katsuhiko Nakamae published by Dainippon Tosho Co., Ltd. ..

For example, any suitable method can be adopted as the polymerization method of the (meth) acrylic polymer (A). Specific examples include solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations.

The polymerization initiator, chain transfer agent, emulsifier and the like used for radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth) acrylic polymer can be controlled by the amount of the polymerization initiator and the chain transfer agent used, and the reaction conditions, and the amount of the (meth) acrylic polymer used is appropriately adjusted according to these types.

For example, in solution polymerization and the like, for example, ethyl acetate, toluene and the like are used as the polymerization solvent. As a specific example of solution polymerization, the reaction is carried out under an inert gas stream such as nitrogen, a polymerization initiator is added, and usually at about 50 to 70 ° C. under reaction conditions of about 5 to 30 hours.

Examples of the thermal polymerization initiator used for solution polymerization and the like include azo-based initiators such as 2,2'-azobisisobutyronitrile; peroxide-based initiators, peroxides and reducing agents. Examples thereof include a combined redox-based initiator, but the present invention is not limited thereto.

The polymerization initiator may be used alone or in combination of two or more, but with respect to 100 parts by mass of all the monomer components constituting the (meth) acrylic polymer (A). It is preferably about 1 part by mass or less, more preferably about 0.005 to 1 part by mass, and further preferably about 0.02 to 0.5 part by mass.

In order to produce the (meth) acrylic polymer (A) using, for example, 2,2'-azobisisobutyronitrile as the polymerization initiator, the amount of the polymerization initiator used is the total amount of the monomer components. It is preferably about 0.2 parts by mass or less, and more preferably about 0.06 to 0.2 parts by mass with respect to 100 parts by mass.

Further, when the (meth) acrylic polymer (A) is produced by radiation polymerization, the monomer component can be produced by polymerizing by irradiating radiation such as an electron beam or UV. When the radiation polymerization is carried out by an electron beam, it is not particularly necessary to include a photopolymerization initiator in the monomer component, but when the radiation polymerization is carried out by UV polymerization, the polymerization time is particularly short. A photopolymerization initiator can be contained in the monomer component because of the advantages of the above. The photopolymerization initiator may be used alone or in combination of two or more.

The weight average molecular weight of the (meth) acrylic polymer (A) used in the present invention is preferably 400,000 to 2.5 million, more preferably 600,000 to 2.2 million. By setting the weight average molecular weight to more than 400,000, it is possible to satisfy the durability of the pressure-sensitive adhesive layer and suppress the cohesive force of the pressure-sensitive adhesive layer from causing adhesive residue. The weight average molecular weight is a value calculated by gel permeation chromatography (GPC) and converted to polystyrene. It is difficult to measure the molecular weight of the (meth) acrylic polymer obtained by radiation polymerization.

The base pressure-sensitive adhesive composition used in the present invention may contain a cross-linking agent. Examples of the cross-linking agent include an organic cross-linking agent and a polyfunctional metal chelate. Examples of the organic cross-linking agent include isocyanate-based cross-linking agents, peroxide-based cross-linking agents, epoxy-based cross-linking agents, and imine-based cross-linking agents. A polyfunctional metal chelate is one in which a polyvalent metal is covalently or coordinated to an organic compound. Examples of the polyvalent metal include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn and Ti. Can be mentioned. Examples of the organic compound include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds. Examples of the atom in the organic compound having a covalent bond or a coordination bond include an oxygen atom. Among these, an isocyanate-based cross-linking agent is preferable as the cross-linking agent.

The isocyanate-based cross-linking agent typically refers to a compound having two or more isocyanate groups in one molecule. For example, isocyanate monomers such as tolylene diisocyanate, chlorphenylene diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate, and isocyanate compounds obtained by adding these isocyanate monomers to trimethylpropane and the like. Examples thereof include isocyanurates, bullet-type compounds, and urethane prepolymer-type isocyanates which have been subjected to an addition reaction with polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols, and the like. Particularly preferred is a polyisocyanate compound, which is one selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived thereto. Here, one type selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate or a polyisocyanate compound derived from the same includes hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and polyol modification. Hexamethylene diisocyanate, polyol-modified hydrogenated xylylene diisocyanate, trimmer-type hydrogenated xylylene diisocyanate, polyol-modified isophorone diisocyanate and the like are included.

As the peroxide, any suitable compound capable of generating radically active species by heating or irradiation with light to promote cross-linking of the base polymer can be adopted. Considering workability and stability, a peroxide having a one-minute half-life temperature of 80 ° C. to 160 ° C. is preferable, and a peroxide having a half-life temperature of 90 ° C. to 140 ° C. is more preferable. Specific examples of peroxides include di (2-ethylhexyl) peroxydicarbonate (1 minute half-life temperature: 90.6 ° C.) and di (4-t-butylcyclohexyl) peroxydicarbonate (1 minute half-life). Temperature: 92.1 ° C), di-sec-butyl peroxydicarbonate (1 minute half-life temperature: 92.4 ° C), t-butyl peroxyneodecanoate (1 minute half-life temperature: 103.5 ° C) ), T-Hexyl peroxypivalate (1 minute half-life temperature: 109.1 ° C), t-butyl peroxypivalate (1 minute half-life temperature: 110.3 ° C), dilauroyl peroxide (1 minute half) Period temperature: 116.4 ° C), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4 ° C), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate (1 minute half-life temperature: 124.3 ° C.), di (4-methylbenzoyl) peroxide (1 minute half-life temperature: 128.2 ° C.), dibenzoyl peroxide (1 minute half-life temperature: 130.0 ° C.) , T-Butylperoxyisobutyrate (1 minute half-life temperature: 136.1 ° C.), 1,1-di (t-hexylperoxy) cyclohexane (1 minute half-life temperature: 149.2 ° C.), etc. Be done. The half-life of peroxide is an index showing the decomposition rate of peroxide, and means the time until the residual amount of peroxide is halved. Therefore, the 1-minute half-life temperature of peroxide means the temperature at which the residual amount of peroxide is halved in 1 minute. The decomposition temperature for obtaining a half-life at an arbitrary temperature and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc., for example, "Organic Peroxide Catalog No. 9" of Nippon Oil & Fats Co., Ltd. Edition (May 2003) ”etc.

The amount of the cross-linking agent used is preferably 0.01 to 20 parts by mass, more preferably 0.03 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer (A). If the amount of the cross-linking agent used is less than 0.01 parts by mass, the cohesive force of the pressure-sensitive adhesive tends to be insufficient, and foaming may occur during heating. If the amount of the cross-linking agent used exceeds 20 parts by mass, the moisture resistance is not sufficient and peeling or the like may easily occur.

The base pressure-sensitive adhesive composition may contain any suitable additive. Examples of the additive include an antistatic agent, an antioxidant, and a coupling agent. The type, amount and combination of additives can be appropriately set according to the purpose.

The content of the base pressure-sensitive adhesive composition in the light-diffusing pressure-sensitive adhesive layer used in the present invention is preferably 50 to 99.7% by mass, more preferably 52 to 97% by mass, and 70 to 97% by mass. Is even more preferable.

The refractive index of the base pressure-sensitive adhesive composition is preferably 1.44 or more, more preferably 1.44 to 1.60, and even more preferably 1.44 to 1.55. When the refractive index of the base pressure-sensitive adhesive composition is within the above range, the difference in refractive index from the light-diffusing fine particles described later can be set within a desired range. As a result, a light diffusing pressure-sensitive adhesive layer having excellent light diffusivity can be obtained after curing, which is preferable.

(1-2) Light-diffusing fine particles In the light-diffusing pressure-sensitive adhesive layer, it is preferable that the light-diffusing fine particles are dispersed in the pressure-sensitive adhesive layer formed from the base pressure-sensitive adhesive composition. As the light diffusing fine particles, any suitable one can be used as long as the effects of the present invention can be obtained. Specific examples include inorganic fine particles and polymer fine particles, and among these, polymer fine particles are preferable.

Examples of the material of the polymer fine particles include silicone resin, methacrylic resin (for example, polymethyl methacrylate), polystyrene resin, polyurethane resin, and melamine resin. Since these resins have excellent dispersibility with respect to the base pressure-sensitive adhesive composition and an appropriate difference in refractive index from the base pressure-sensitive adhesive composition, a light-diffusing pressure-sensitive adhesive layer having excellent diffusion performance can be obtained. Among these, silicone resin and polymethyl methacrylate are particularly preferable.

The shape of the light diffusing fine particles can be, for example, a true spherical shape, a flat shape, or an indefinite shape. The light diffusing fine particles may be used alone or in combination of two or more.

The refractive index of the light diffusing fine particles used in the present invention is preferably lower than the refractive index of the base pressure-sensitive adhesive composition. The refractive index of the light diffusing fine particles is preferably 1.30 to 1.70, more preferably 1.40 to 1.65. When the refractive index of the light diffusing fine particles is within the above range, a light diffusing pressure-sensitive adhesive layer having excellent light diffusivity can be obtained, and the reflectance Y of the electromagnetic wave transmitting laminate can be easily set within a desired range, which is preferable.

The absolute value of the difference in refractive index between the light diffusing fine particles and the base pressure-sensitive adhesive composition is preferably more than 0 and 0.2 or less, more preferably more than 0 and 0.15 or less, and 0. It is more preferably 0.01 to 0.13.

The volume average particle size of the light diffusing fine particles is preferably about 1 to 5 μm, more preferably about 2 to 5 μm, and even more preferably about 2 to 4 μm. When the volume average particle diameter of the light diffusing fine particles is within the above range, a light diffusing pressure-sensitive adhesive layer having excellent light diffusivity can be obtained, and the reflectance Y of the electromagnetic wave transmitting laminate can be easily set within a desired range. Therefore, it is preferable. The volume average particle size can be measured using, for example, an ultracentrifugal automatic particle size distribution measuring device.

The content of the light diffusing fine particles in the light diffusing pressure-sensitive adhesive layer is not particularly limited, but is preferably 0.3 to 50% by mass, more preferably 3 to 48% by mass, and 3 It is more preferably ~ 30% by mass. By setting the blending amount of the light diffusing fine particles within the above range, a light diffusing pressure-sensitive adhesive layer having excellent light diffusing performance can be obtained.
The light diffusing performance of the light diffusing pressure-sensitive adhesive layer can be controlled by adjusting the constituent material of the matrix (adhesive), the constituent material of the light diffusing fine particles, the volume average particle size, the blending amount, and the like.

(1-3) Method for Forming Light Diffuse Adhesive Layer The method for forming the pressure-sensitive adhesive layer is not particularly limited, but for example, the pressure-sensitive adhesive composition is applied onto various substrates, a solvent or the like is dried and removed, and the like. If necessary, a cross-linking treatment may be performed to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer may be transferred onto the metallic luster layer. The pressure-sensitive adhesive composition may be directly applied onto the metallic luster layer. It may be applied to form an adhesive layer.
For example, it can be formed by applying a light-diffusing pressure-sensitive adhesive composition in which light-diffusing fine particles are dispersed in the base pressure-sensitive adhesive composition onto a metallic luster layer and drying and removing a solvent or the like. When applying the light diffusing pressure-sensitive adhesive composition, one or more solvents may be added as appropriate. When the base pressure-sensitive adhesive composition is an active energy ray-curable type, a prepolymer obtained by polymerizing a part of the base pressure-sensitive adhesive composition is produced, and light-diffusing fine particles are dispersed in the prepolymer. A light-diffusing pressure-sensitive adhesive layer can be formed by applying the pressure-sensitive adhesive composition on a metallic glossy layer and irradiating the coating layer with active energy rays such as ultraviolet rays. Further, when the above-mentioned transparent conductive layer is provided, the light diffusing pressure-sensitive adhesive composition can be applied onto the transparent conductive layer to form the light diffusing pressure-sensitive adhesive layer.

The thickness of the light diffusing pressure-sensitive adhesive layer is preferably 5 to 300 μm, more preferably 5 to 250 μm, further preferably 10 to 250 μm, and even more preferably 15 to 200 μm. It is particularly preferable that the thickness is more than 15 μm and 150 μm or less. When the thickness of the light diffusing pressure-sensitive adhesive layer is 5 μm or more, it is preferable that the material to be bonded can be bonded by following the minute unevenness of the material to be bonded or the uneven portion for imparting an optical function. Further, it is preferable that the thickness of the light diffusing pressure-sensitive adhesive layer is 300 μm or less, and from the viewpoint of thinning the housing.
Further, when the transparent pressure-sensitive adhesive layer is bonded to the light-diffusing pressure-sensitive adhesive layer, the thickness of the light-diffusing pressure-sensitive adhesive layer is about 5 to 100 μm, which affects the peripheral members due to the physical properties of the light-diffusing pressure-sensitive adhesive. It is preferable from the viewpoint that it does not affect the bonding effect of the above, and more preferably about 5 to 30 μm. When the light diffusing pressure-sensitive adhesive layer is composed of two or more layers, the total thickness of all the light diffusing pressure-sensitive adhesive layers may be within the above range.

Various methods are used as a method for applying the light diffusing pressure-sensitive adhesive composition. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples include a method such as an extrusion coating method.

The heating and drying temperature is preferably about 30 ° C. to 200 ° C., more preferably 40 ° C. to 180 ° C., and even more preferably 80 ° C. to 160 ° C. By setting the heating temperature within the above range, an adhesive layer having excellent adhesive properties can be obtained. As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably about 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, and even more preferably 1 minute to 8 minutes.

When the base pressure-sensitive adhesive composition is an active energy ray-curable pressure-sensitive adhesive, a light-diffusing pressure-sensitive adhesive layer can be formed by irradiating with active energy rays such as ultraviolet rays. A high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a chemical light lamp, or the like can be used for ultraviolet irradiation.

The various base materials function as a support, and for example, a peeled sheet can be used. A silicone release liner is preferably used as the release-treated sheet.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a peel-treated sheet (separator) until it is put into practical use. .. In practical use, the peeled sheet is peeled off.

Examples of the constituent material of the separator include porous materials such as plastic film, paper, cloth, and non-woven fabric, nets, foam sheets, metal foils, and appropriate thin leaves such as laminates thereof. A plastic film is preferably used because of its excellent surface smoothness.

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene. -Vinyl acetate copolymer film and the like can be mentioned.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be used for mold release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, etc., as well as a coating type, a kneading type, and a vapor deposition type. It is also possible to carry out antistatic treatment such as. In particular, the peelability from the pressure-sensitive adhesive layer can be further enhanced by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator.

(Hard coat layer)
The electromagnetic wave transmitting laminate 1 may further include a hard coat layer.
The hard coat layer 13b is formed from, for example, a hard coat composition. The hard coat composition contains a resin component, preferably composed of a resin component.

Examples of the resin component include a curable resin, a thermoplastic resin (for example, a polyolefin resin), and the like, and a curable resin is preferable.

The thickness of the hard coat layer is, for example, 0.5 μm or more, preferably 1.0 μm or more, and for example, 10 μm or less, preferably 3.0 μm or less, more preferably 2.0 μm or less. The thickness of the hard coat layer can be measured using, for example, a film thickness meter (digital dial gauge).

<7. Manufacture of electromagnetic wave transmissive laminate>
An example of a method for manufacturing the electromagnetic wave transmitting laminated body 1 will be described. Although not particularly described, it can be produced by the same method when a substrate other than the substrate film is used.

When the metallic luster layer is a metal layer, a method such as vacuum deposition or sputtering can be used to form the metal layer 12 on the substrate 10.
When the metallic luster layer is a resin layer, it is possible to realize metallic luster by laminating and forming resin layers having different refractive indexes. For example, a method such as a feed block method or a multi-manifold method for resin having different refractive indexes. Can be made by

When the indium oxide-containing layer 11 is formed on the substrate 10, the indium oxide-containing layer 11 is formed by vacuum deposition, sputtering, ion plating, or the like prior to the formation of the metallic luster layer. However, sputtering is preferable because the thickness can be strictly controlled even in a large area.

When the indium oxide-containing layer 11 is provided between the substrate 10 and the metallic luster layer, it is preferable that the indium oxide-containing layer 11 and the metallic luster layer are in direct contact with each other without interposing another layer.

<8. Applications of electromagnetic wave transmissive laminates and metal thin films>
Since the electromagnetic wave-transmitting laminate of the present embodiment has electromagnetic wave transmission property, it is preferable to use it for a device or an article for transmitting and receiving electromagnetic waves, its parts, and the like. For example, applications for household goods such as structural parts for vehicles, vehicle-mounted products, housings for electronic devices, housings for home appliances, structural parts, mechanical parts, various automobile parts, electronic device parts, furniture, kitchen supplies, etc. , Medical equipment, building material parts, other structural parts, exterior parts, etc.
More specifically, in the case of vehicles, instrument panels, console boxes, doorknobs, door trims, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seats, steering wheels. , ECU box, electrical parts, engine peripheral parts, drive system / gear peripheral parts, intake / exhaust system parts, cooling system parts and the like.
More specifically, as electronic devices and home appliances, home appliances such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, TVs, watches, ventilation fans, projectors, speakers, personal computers, mobile phones , Smartphones, digital cameras, tablet PCs, portable music players, portable game machines, chargers, electronic information devices such as batteries, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. Various samples were prepared for the electromagnetic wave transmissive laminate 1, and the reflectance, haze value, sheet resistance, and radio wave transmissivity were evaluated. As the substrate 10, a substrate film was used.
Sheet resistance is an evaluation of electromagnetic wave transmission.
The details of the evaluation method are as follows.

(1) Reflectance The prepared electromagnetic wave transmitting laminate is attached to a glass plate (S200S200 manufactured by Matsunami Glass Industry Co., Ltd.) having a thickness of 1.3 mm, and a spectrocolorimeter CM-2600d manufactured by Konica Minolta is used to obtain a wavelength. The reflectance Y (%) was measured for visible light in the range of 380 nm to 780 nm. These measured values are values via the glass plate.
At the time of measurement, D65 was used as a standard light source, and the visible light was incident on the side of the surface of the obtained electromagnetic wave transmitting laminate where the metallic luster layer was provided.

(2) Haze value The haze value of each light diffusing pressure-sensitive adhesive layer and the transparent pressure-sensitive adhesive layer used in Examples and Comparative Examples, and the total haze value of the pressure-sensitive adhesive layers obtained in Examples and Comparative Examples are defined by JIS 7136. By the method, it was measured using a haze meter (consumer name: HN-150, manufactured by Murakami Color Science Institute Co., Ltd.).

(3) Sheet resistance Using a non-contact resistance measuring device NC-80MAP manufactured by Napson, the sheet resistance as a laminate of a metallic luster layer and an indium oxide-containing layer was measured by an eddy current measurement method in accordance with JIS-Z2316. .. The electromagnetic wave transmissivity of the electromagnetic wave transmissive laminate was judged according to the following criteria according to the obtained sheet resistance value.

(Evaluation criteria for sheet resistance)
Less than 100Ω / □: × (defective)
100Ω / □ or more: ○ (good)

(4) Radio wave transmission The amount of radio wave transmission attenuation at 5 GHz was measured by sandwiching a sample with a square waveguide measurement evaluation jig WR-187 and using a spectrum analyzer MS4644B manufactured by Anritsu.
There is a correlation between the electromagnetic wave transmission in the frequency band (76 to 80 GHz) of the millimeter-wave radar and the electromagnetic wave transmission in the microwave band (5 GHz), and they show relatively close values. Therefore, in this evaluation, microwaves are used. The electromagnetic wave transmittance in the band (5 GHz), that is, the amount of microwave electric field transmission attenuation was used as an index.

(5) Evaluation Method of Film Thickness First, as shown in FIG. 6, a square region 3 having a side of 5 cm is appropriately extracted from the electromagnetic wave transmitting laminated body, and the center lines A of the vertical side and the horizontal side of the square region 3 are appropriately extracted. , And B were divided into four equal parts, and a total of five points "a" to "e" obtained were selected as measurement points.
Next, a cross-sectional image (transmission electron micrograph (TEM image)) as shown in FIG. 7 is measured at each of the selected measurement points, and the obtained TEM image includes five or more metal portions 12a. The viewing angle region was extracted.
The total cross-sectional area of the metal layer in the viewing angle region extracted at each of the five measurement points divided by the width of the viewing angle region is defined as the film thickness of the metal layer in each viewing angle region. The average value of the film thickness of the metal layer in each viewing angle region was defined as the metal layer thickness (nm).

[Example 1]
(Manufacturing of light diffusing pressure-sensitive adhesive composition)
100 parts by mass of butyl acrylate, 5 parts by mass of acrylic acid, 1 part by mass of hydroxyethyl acrylate, 2,2'-as a polymerization initiator in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. 0.1 part by mass of azobisisobutyronitrile was charged together with 100 parts by mass of ethyl acetate (monomer concentration 50%), nitrogen gas was introduced with gentle stirring to replace nitrogen, and then the liquid temperature in the flask was 55. The polymerization reaction was carried out for 8 hours while keeping the temperature at around ° C. to prepare a solution of acrylic polymer 1 having a weight average molecular weight (Mw) of 1.8 million.

An isocyanate-based cross-linking agent (trade name: Coronate L, trimethylolpropane / tolylene diisocyanate trimer adduct, Nippon Polyurethane Industry Co., Ltd.) with respect to 100 parts by mass of the solid content of the acrylic polymer 1 solution obtained above. 0.66 parts by mass, benzoyl peroxide (Niper BMT, manufactured by Nippon Polyurethane Industry Co., Ltd.) 0.3 parts by mass, silane coupling agent (trade name: KBM403, manufactured by Shin-Etsu Chemical Industry Co., Ltd.) 0.2 mass Part was added to obtain a base pressure-sensitive adhesive composition 1.

Silicone resin fine particles (trade name: Tospearl 145, volume average particle diameter: 4 μm, refractive index: 1.43, silicone) as light diffusible fine particles with respect to 100 parts by mass of the solid content of the obtained base pressure-sensitive adhesive composition 1. A light diffusing pressure-sensitive adhesive composition 1 was prepared by blending 2 parts by mass of resin-based fine particles and Momentive Performance Materials Co., Ltd.).

(Manufacturing of electromagnetic wave transmissive laminate)
As the base film, a PET film (thickness 50 μm) on which a hard coat layer was formed was used.
First, DC magnetron sputtering was used to form an ITO layer with a thickness of 5 nm directly on the surface of the base film. The temperature of the base film when forming the ITO layer was set to 130 ° C. The content of tin oxide (SnО ₂ ) contained in ITO (content rate = (SnO ₂ / (In ₂ O ₃ + SnO ₂ )) × 100) is 10% by mass.

Next, AC sputtering (AC: 40 kHz) was used to form an aluminum (Al) layer having a thickness of 17 nm on the ITO layer. The obtained aluminum layer was a discontinuous layer. The temperature of the base film when forming the Al layer was set to 130 ° C.
Then, by using direct current sputtering (DC: 100 kHz, 1 μsec), an aluminum-doped zinc oxide (AZO) layer having a thickness of 70 nm was formed on the aluminum layer to obtain a laminate 1. The temperature at which the AZO layer was formed was set to 130 ° C. Further, the amount of radio wave transmission attenuation of the obtained laminated body 1 was measured and found to be −0.02 dB.

After drying the light diffusion pressure-sensitive adhesive composition obtained above on one side of a polyethylene terephthalate film (polyester film manufactured by Mitsubishi Chemical Co., Ltd., trade name "MRF-38", separator film) treated with a silicone-based release agent. The pressure-sensitive adhesive layer was applied so as to have a thickness of 20 μm and dried at 155 ° C. for 1 minute to form a pressure-sensitive adhesive layer on the surface of the separator film. Next, the pressure-sensitive adhesive layer formed on the separator film was transferred to the surface of the laminate 1 obtained above on the metal layer side to obtain an electromagnetic wave-transmitting laminate.

[Examples 2 to 5]
The electromagnetic wave transmitting laminates of Examples 2 to 5 were produced in the same manner as in Example 1 except that the amount of the silicone resin fine particles used for preparing the light diffusing pressure-sensitive adhesive composition was changed as shown in Table 1.

[Comparative Example 1]
An electromagnetic wave transmitting laminate of Comparative Example 1 was produced in the same manner as in Example 1 except that silicone resin fine particles were not added to the preparation of the light diffusing pressure-sensitive adhesive composition. The obtained aluminum layer was a discontinuous layer.

[Examples 6 to 10]
Electromagnetic wave transmissive lamination of Examples 6 to 10 in the same manner as in Example 1 except that the amount of silicone resin fine particles used for preparing the light diffusing pressure-sensitive adhesive composition and the thickness of the aluminum layer were changed as shown in Table 1. Manufactured the body. The obtained aluminum layer was a discontinuous layer.

[Comparative Example 2]
An electromagnetic wave transmitting laminate of Comparative Example 2 was produced in the same manner as in Example 6 except that silicone resin fine particles were not added to the preparation of the light diffusing pressure-sensitive adhesive composition. The obtained aluminum layer was a discontinuous layer.
The evaluation results are shown in Table 1 below.

As is clear from Table 1, in Examples 1 to 10, the reflectance Y was in the range of 1 to 60%, and an electromagnetic wave transmissive laminate having a good metallic appearance with suppressed brilliance was obtained.
On the other hand, the electromagnetic wave transmitting laminates of Comparative Examples 1 and 2 had a reflectance Y of less than 1%, and was inferior in appearance to metal as compared with Examples 1 to 10.

Regarding metals other than aluminum (Al) particularly used in the above examples, metals having a relatively low melting point such as zinc (Zn), lead (Pb), copper (Cu), and silver (Ag) are used. , It is considered that a discontinuous structure can be formed by the same method.

The present invention is not limited to the above-described embodiment, and can be appropriately modified and embodied without departing from the spirit of the invention.

The electromagnetic wave transmissive laminate according to the present invention can be used for devices, articles, and parts thereof that transmit and receive electromagnetic waves. For example, applications for household goods such as structural parts for vehicles, vehicle-mounted products, housings for electronic devices, housings for home appliances, structural parts, mechanical parts, various automobile parts, electronic device parts, furniture, kitchen supplies, etc. It can also be used for various applications that require both design and electromagnetic wave transmission, such as medical equipment, building material parts, other structural parts and exterior parts.

1 Electromagnetic wave transmissive laminate 10 Base 11 Indium oxide-containing layer 12 Metal layer 12a Part 12b Gap 13 Resin layer 13a Light diffusion adhesive layer 13b Hard coat layer

Claims (14)

A substrate, a metallic luster layer formed on the substrate, and a resin layer are provided.
An electromagnetic wave transmissive laminate having a reflectance Y of 1 to 60% in SCE measurement of the CIE-XYZ color system of reflected light in the wavelength range of 380 nm to 780 nm. The metallic luster layer is a metal layer,
The electromagnetic wave transmissive laminate according to claim 1, wherein the metal layer includes a plurality of portions that are discontinuous with each other at least in part. The electromagnetic wave transmitting laminate according to claim 2, wherein the metal layer is a layer containing aluminum or an aluminum alloy. The electromagnetic wave transmitting laminate according to any one of claims 1 to 3, wherein the resin layer contains a layer containing light diffusing fine particles. The electromagnetic wave transmitting laminate according to any one of claims 1 to 4, wherein the resin layer contains a light diffusing pressure-sensitive adhesive layer. The electromagnetic wave transmitting laminate according to any one of claims 1 to 5, further comprising an indium oxide-containing layer between the substrate and the metallic luster layer. The electromagnetic wave transmitting laminate according to claim 6, wherein the indium oxide-containing layer is provided in a continuous state. The electromagnetic wave transmissive laminate according to claim 6 or 7, wherein the indium oxide-containing layer contains _{any one of indium oxide (In 2} O ₃ ), indium tin oxide (ITO), and indium zinc oxide (IZO). .. The electromagnetic wave transmitting laminate according to any one of claims 6 to 8, wherein the thickness of the indium oxide-containing layer is 1 nm to 1000 nm. The electromagnetic wave transmitting laminate according to any one of claims 6 to 9, wherein the thickness of the metallic luster layer is 5 nm to 100 nm. The ratio of the thickness of the metallic luster layer to the thickness of the indium oxide-containing layer (thickness of the metallic luster layer / thickness of the indium oxide-containing layer) is 0.02 to 100 according to claims 6 to 10. The electromagnetic wave transmissive laminate according to any one item. The electromagnetic wave transmissive laminate according to any one of claims 1 to 11, wherein the sheet resistance is 100 Ω / □ or more. The electromagnetic wave transmitting laminate according to claim 2, wherein the plurality of portions are formed in an island shape. The electromagnetic wave transmissive laminate according to any one of claims 1 to 13, wherein the substrate is a substrate film, a resin molded substrate, a glass substrate, or an article to which metallic luster should be imparted.