WO2021065839A1

WO2021065839A1 - Multilayer body

Info

Publication number: WO2021065839A1
Application number: PCT/JP2020/036743
Authority: WO
Inventors: 正義片桐; 孝洋中井; 秀行米澤
Original assignee: 日東電工株式会社
Priority date: 2019-09-30
Filing date: 2020-09-28
Publication date: 2021-04-08
Also published as: WO2021065840A1; TW202120323A; TW202120324A

Abstract

The present invention relates to a multilayer body which is sequentially provided with a base material film, an optical adjustment layer, a barrier layer and an adhesive layer in this order, wherein: the optical adjustment layer has a refractive index of 1.75 or more, while containing at least one substance that is selected from the group consisting of metal oxides, metal nitrides and metal sulfides; the barrier layer contains a metal oxide and/or a metal nitride; and the adhesive layer is formed of a transparent adhesive.

Description

Laminate

The present invention relates to a laminate.

Conventionally, a laminated body that is attached to an article to decorate the article is known. As such a laminated body, for example, a decorative film having electromagnetic wave transmission and metallic luster, in which a base film, a metal layer, an adhesive layer and the like are laminated, is known.

Such a film has both a high-class appearance derived from its metallic luster and electromagnetic wave transmission, and is therefore suitably used for decoration of a device that transmits and receives radio waves. For example, it is used for housings of mobile phones, smartphones, computers, etc., and decoration of the front part of automobiles. Furthermore, in recent years, with the development of IoT technology, home appliances and household appliances are also equipped with communication functions, and are expected to be applied in a wider range of fields.

For example, in Patent Document 1, in a transfer film transferred to a molded projectile, a protective layer, a printing layer laminated on the protective layer, and a non-conducting film deposited on the printing layer in an island structure. A non-conductive transfer film having a metallic luster is disclosed, which comprises a metal-deposited layer having a property and an adhesive layer laminated on the metal-deposited layer.

Japan Special Table 2014-509268 Gazette

In such a laminate, a colored appearance may be desired. As a method for meeting such needs, a method of further laminating an optical adjustment layer as a layer constituting the laminated body can be considered.
In a laminate having an optical adjustment layer, a configuration having an adhesive layer on the optical adjustment layer, for example, a configuration in which a base material, an optical adjustment layer, and an adhesive layer are provided in this order may be desired. For example, when decorating the adherend member from the inside (opposite side of the visible surface), a laminate (film) having such a structure is desired. When a film having such a structure is attached to the inside of the transparent adherend member, a colored appearance due to the optical adjustment layer can be imparted to the adherend member. Further, since the film is located inside the adherend member, it is not easily scratched. Further, since the adherend member is located on the outside, the texture of the adherend member can be utilized as it is in the product.

However, in such a film, there is a problem that the optical adjustment layer is deteriorated due to various factors such as ultraviolet rays, temperature, and humidity, and the appearance thereof is changed.

The present invention has been made in view of the above, and it is possible to decorate the adherend member to give a colored appearance, and further, the change in appearance due to various factors such as ultraviolet rays, temperature, and humidity is suppressed. It is an object of the present invention to provide a laminated body.

The laminate of the present invention that solves the above problems is a laminate that includes a base film, an optical adjustment layer, a barrier layer, and an adhesive layer in this order, and the optical adjustment layer is a metal oxide and a metal nitride. A layer having a refractive index of 1.75 or more containing at least one selected from the group consisting of a substance and a metal sulfide, and the barrier layer is a layer containing a metal oxide and / or a metal nitride and is adhesive. The agent layer is a layer made of a transparent pressure-sensitive adhesive.
In one aspect of the laminate of the present invention, a metal layer may be further provided between the base film and the optical adjustment layer.
In one aspect of the laminate of the present invention, the metal layer may include a plurality of portions that are discontinuous with each other, at least in part.
In one aspect of the laminate of the present invention, an indium oxide-containing layer may be further provided between the base film and the metal layer.
In one aspect of the laminate of the present invention, the optical conditioning layer may contain Si and / or Nb.
In one aspect of the laminate of the present invention, the barrier layer may contain _{SiO 2.}
In one aspect of the laminate of the present invention, the reflection spectrum obtained by laminating the laminate on a glass plate via an adhesive layer and irradiating the laminate with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. The reflection spectrum obtained by irradiating the laminate bonded to the glass plate with ultraviolet light through the glass plate for 24 hours and then irradiating the laminate with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. The color difference ΔE calculated using the above may be 3 or less.
In one aspect of the laminate of the present invention, the reflection spectrum obtained by laminating the laminate on a glass plate via an adhesive layer and irradiating the laminate with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. After holding the laminate bonded to the glass plate at a temperature of 65 ° C. and humidity of 90% for 500 hours, the laminate is irradiated with visible light having a wavelength in the range of 380 nm to 780 nm. The difference from the minimum wavelength in the obtained reflection spectrum may be 15 nm or less.

The laminate of the present invention can decorate the adherend member to give a colored appearance, and can further suppress changes in the appearance due to various factors such as ultraviolet rays, temperature, and humidity.

FIG. 1 is a schematic cross-sectional view of a laminated body according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a method of measuring the film thickness of the metal layer of the laminated body according to the embodiment of the present invention.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below. Further, in the following drawings, members / parts having the same action may be described with the same reference numerals, and duplicate description may be omitted or simplified. In addition, the embodiments described in the drawings are modeled in order to clearly explain the present invention, and do not necessarily accurately represent the actual size and scale.

[Laminate]
FIG. 1 shows a schematic cross-sectional view of a laminated body according to an embodiment of the present invention. The laminate 1 of the present embodiment includes a base film 10, an optical adjustment layer 13, a barrier layer 14, and an adhesive layer 15 in this order.

<Base film>
The base film 10 includes, for example, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polypropylene (PP), and the like. A film made of a homopolymer or copolymer such as polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), and ABS can be used. According to these members, it does not affect the brilliance and radio wave transmission described later. However, since various layers are formed on the base film 10 later, it is preferable that the film can withstand high temperatures such as vapor deposition and sputtering. Therefore, among the above materials, for example, polyethylene terephthalate, polyethylene naphthalate, and acrylic. , Polycarbonate, cycloolefin polymer, ABS, polypropylene, polyurethane are preferable. 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 10 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. Further, in order to strengthen the adhesive force with the layer formed on the base film 10, plasma treatment, easy adhesion treatment, or the like may be performed. Further, as will be described in detail later, the base film 10 may have a light-shielding property.

The base film 10 may be formed with a smooth or antiglare hard coat layer, if necessary. By providing the hard coat layer, scratch resistance can be improved.
In particular, by providing the smooth hard coat layer, the metallic luster can be improved when the metal layer 12 described later is provided, while by providing the antiglare hard coat layer, glare can be prevented. ..
The hard coat layer can be formed by applying a solution containing a curable resin. Examples of the curable resin include thermosetting resins, ultraviolet curable resins, and electron beam curable resins. Examples of the curable resin include various resins such as polyester-based, acrylic-based, urethane-based, acrylic-urethane-based, amide-based, silicone-based, silicate-based, epoxy-based, melamine-based, oxetane-based, and acrylic urethane-based. As these curable resins, one kind or two or more kinds can be appropriately selected and used. Among these, acrylic resins, acrylic urethane resins, and epoxy resins are preferable because they have high hardness, can be cured by ultraviolet rays, and are excellent in productivity.

<Indium oxide-containing layer>
When the laminate 1 includes the metal layer 12 described later, the indium oxide-containing layer 11 may be provided between the base film 10 and the metal layer 12.
_{Indium oxide (In 2} O ₃ ) itself can be used as the indium oxide-containing layer 11, and other than indium and indium such as indium tin oxide (ITO) and indium zinc oxide (IZO), for example. A composite oxide containing the same metal (second metal) can also be used. However, ITO and IZO containing a second metal are more preferable because they have high discharge stability in the sputtering process. Although the details will be described later, by using the indium oxide-containing layer 11, it becomes easy to form the metal layer 12 into an island-shaped discontinuous structure, and aluminum or the like, which has been difficult to form a discontinuous structure in the past, can be easily formed into the metal layer 12. Become applicable.

When ITO is used as the indium oxide-containing layer 11, the content rate (content rate = (SnO ₂ / (In ₂ O ₃ + SnO ₂ )) × 100), _{which is the weight ratio of tin oxide (SnО 2) contained in ITO, is particularly high.} Although not limited, it is, for example, 2.5 wt% to 30 wt%, more preferably 3 wt% to 10 wt%.

Further, when IZO is used as the indium oxide-containing layer 11, the content rate (content rate = (ZnO / (In ₂ O ₃ + ZnO)) × 100) which is the weight ratio of zinc oxide (ZnO) contained in IZO is, for example. It is 2 wt% to 20 wt%.

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 electromagnetic wave transmission and productivity. On the other hand, in order to facilitate the formation of the discontinuous metal layer 12, the thickness of the indium oxide-containing layer 11 is preferably 1 nm or more, more preferably 2 nm or more, still more preferably 5 nm or more.

<Metal layer>
The laminate 1 may further include a metal layer 12 between the base film 10 and the optical adjustment layer 13. The laminate 1 can be made into a metallic luster film by further including the metal layer 12. With such a configuration, it is possible to give a colored metallic luster-like appearance to the article to be decorated (adhesive member).
When the laminate 1 includes the metal layer 12, the metal layer 12 is formed on the base film 10 (on the indium oxide-containing layer 11 when the indium oxide-containing layer 11 is provided). In this case, the metal layer 12 preferably includes a plurality of portions 12a that are discontinuous with each other at least in part. These portions 12a are, at least in part, discontinuous with each other, in other words, at least in part, separated by a gap 12b. When the plurality of portions 12a are separated by the gap 12b, the sheet resistance of the laminated body 1 is large and the interaction with the radio wave is small, so that the radio wave can be transmitted.
The "discontinuous state" as used herein means a state in which a plurality of portions 12a 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 of the metal layer 12 increases, and radio wave transmission can be obtained. That is, according to the metal layer 12 formed in a discontinuous state, it is possible to secure radio wave transmission while ensuring sufficient brilliance.

The discontinuous structure including the plurality of portions 12a and the gap 12b is not particularly limited, and examples thereof include an island structure and a crack structure, but an island structure is preferable from the viewpoint of productivity.

The island-like structure is a structure in which the metal particles are independent of each other and are laid out in a state where they are slightly separated from each other or partially in contact with each other.
The island-shaped metal layer 12 can be formed, for example, by depositing or sputtering a metal on the base film 10 (on the indium oxide-containing layer 11 when the indium oxide-containing layer 11 is provided).
The details of the mechanism by which the metal layer 12 formed by vapor deposition, sputtering, or the like becomes discontinuous on the base film 10 are not necessarily clear, but the ease of forming the discontinuous structure is given by the metal layer 12. It is considered to be related to the surface diffusivity on the substrate. Therefore, it is considered that a discontinuous structure is more likely to be formed when the temperature of the substrate is high, the wettability of the metal layer 12 with respect to the substrate is small, and the melting point of the metal constituting the metal layer 12 is low. Therefore, in the following examples, aluminum (Al) is used as the metal constituting the metal layer 12, but other metals such as zinc (Zn), lead (Pb), copper (Cu), and silver (Ag) are used. For metals with a relatively low melting point, it is considered that a discontinuous structure can be formed by the same method.
Further, the indium oxide-containing layer 11 makes it easy for the metal layer 12 to have an island-like discontinuous structure because the indium oxide-containing layer 11 improves the surface diffusivity of the metal constituting the metal layer 12. It is believed that there is.

The thickness of the metal layer 12 having an island-like structure is not particularly limited, but is preferably 20 nm or more, and more preferably 30 nm or more, from the viewpoint of improving the metallic luster. On the other hand, from the viewpoint of improving the electromagnetic wave transmission, the thickness of the metal layer 12 having the island-like structure is preferably 100 nm or less, more preferably 70 nm or less.
The circle-equivalent diameter of the metal portion 12a in the metal layer 12 having an island-like structure is not particularly limited, but is usually about 10 to 1000 nm. The distance between the portions 12a is not particularly limited, but is usually about 10 to 1000 nm.
These can be obtained from, for example, an SEM image.

The crack structure is a structure in which a metal thin film is divided by cracks.
The metal layer 12 having a crack structure is provided with, for example, a metal thin film layer on the base film 10 (on the indium oxide-containing layer when the indium oxide-containing layer 11 is provided), and is bent and stretched to generate cracks in the metal thin film layer. Can be formed by 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 10 and the metal thin film layer. it can.

The type of metal constituting the metal layer 12 is not particularly limited, and may be one type of metal or two or more types of metal.
As described above, the ease of forming a discontinuous structure is related to the surface diffusivity on the substrate (base film), the temperature of the substrate is high, the wettability of the metal layer to the substrate is small, and the material of the metal layer. From this point of view, the metal layer preferably contains a metal having a relatively low melting point, and is composed of, for example, Al, Zn, Pb, Cu, and Ag. It is preferable to contain at least one metal selected from the group and any of the alloys containing the metal as a main component. In particular, the metal layer is preferably made of Al or an Al alloy for reasons of brilliance, stability, price and the like. When an Al alloy is used, the Al content is preferably 50% by mass or more.

When the laminate 1 includes the indium oxide-containing layer 11, the ratio of the thickness of the metal layer 12 to the thickness of the indium oxide-containing layer 11 (thickness of the metal layer / thickness of the indium oxide-containing layer) is 0.1 to. The range of 100 is preferable, and the range of 0.3 to 35 is more preferable.

<Optical adjustment layer>
The optical adjustment layer 13 is a layer having a refractive index of 1.75 or more containing at least one selected from the group consisting of metal oxides, metal nitrides, and metal sulfides.
When the refractive index of the optical adjustment layer 13 is 1.75 or more, a colored appearance can be obtained. In order to obtain a darker appearance, the refractive index of the optical adjustment layer 13 is preferably 1.8 or more, and more preferably 1.9 or more. Further, from the viewpoint of thickness controllability, the refractive index of the optical adjustment layer 13 is preferably 3.5 or less, more preferably 3.0 or less.
Further, the optical adjustment layer 13 may be a laminated body of layers having different refractive indexes.

The material constituting the optical adjustment layer 13 is not particularly limited, and at least one selected from the group consisting of metal oxides, metal nitrides, and metal sulfides can be appropriately used. The metal element contained in the metal oxide, the metal oxide, and the metal sulfide here includes a metalloid element such as Si. Further, at least one selected from the group consisting of metal oxides, metal nitrides, and metal sulfides includes metal acid nitrides, metal acid sulfides, and metal sulfur nitrides. Further, the metal oxide may be an oxide of a single metal element (single oxide) or an oxide of a plurality of metal elements (composite oxide). Similarly, the metal nitride may be a single metal element nitride (single nitride) or a plurality of metal element nitrides (composite nitride), and the metal sulfide may be a single metal sulfide. It may be a sulfide of a metal element (single sulfide) or a sulfide of a plurality of metal elements (composite sulfide).
More specifically, as the material of the optical adjustment layer 13, for example, CeO ₂ (2.30), Nb ₂ O ₃ (2.15), Nb ₂ O ₅ (2.20), SiN _x (2. 03), Sb ₂ O ₃ (2.10), TiO ₂ (2.35), Ta ₂ O ₅ (2.10), ZrO ₂ (2.05), ZnO (2.10), ZnS (2. 30) and the like [the numerical value in parentheses of each of the above materials is the refractive index].
In particular, it is preferable that the optical adjustment layer 13 containing Si and / or Nb, for example, preferably contains _Nb 2 _{O 5} and / or SiN _X, and more preferably consisting of _Nb 2 _{O 5} and / or SiN _X ..

The thickness of the optical adjustment layer 13 is preferably 10 nm to 1000 nm. From the viewpoint of cost, it is more preferably 800 nm or less, and further preferably 500 nm or less. Further, from the viewpoint of color, it is preferably 15 nm or more, more preferably 20 nm or more, and further preferably 30 nm or more.

<Barrier layer>
The barrier layer 14 is a layer containing a metal oxide and / or a metal nitride. The metal oxide and the metal element contained in the metal oxide here include a metalloid element such as Si. Further, the metal oxide and / or the metal nitride includes a metal oxynitride. Further, the metal oxide may be an oxide of a single metal element (single oxide) or an oxide of a plurality of metal elements (composite oxide). Similarly, the metal nitride may be a single metal element nitride (single nitride) or a plurality of metal element nitrides (composite nitride).
The present inventors have changed the appearance of the laminate 1 by exposing the laminate 1 to ultraviolet rays (UV rays) or when the laminate 1 is exposed to a high temperature and high humidity environment, the optical adjustment layer 13 and the pressure-sensitive adhesive layer. It was found that 15 was due to the reaction. Therefore, by providing the barrier layer 14 between the optical adjustment layer 13 and the pressure-sensitive adhesive layer 15 and suppressing these reactions, it is possible to suppress the change in the appearance of the laminated body 1.

The material forming the barrier layer 14 is not particularly limited as long as it is transparent and does not react with the pressure-sensitive adhesive layer 15 and the optical adjustment layer 13, but for example, SiO ₂ , Al ₂ O ₃ , AZO and the like are preferable. It preferably contains SiO _2, and more preferably consists of _{SiO 2.}

From the viewpoint of transparency, it is preferable that the barrier layer 14 has a small optical absorption. For example, the barrier layer preferably has an absorption rate of light having a wavelength of 550 nm of 20% or less, more preferably 10% or less, and further preferably 5% or less. The absorption rate of the barrier layer can be measured by the method shown below.

(Measurement method of absorption rate)
The laminate 1 is attached to a glass plate via an adhesive layer 15, and the laminate 1 is irradiated with visible light having a wavelength in the range of 380 nm to 780 nm using a spectrophotometer U-4100 manufactured by Hitachi High-Tech. The value obtained by subtracting the reflectance and the transmittance at a wavelength of 550 nm of the reflection spectrum and the transmission spectrum thus obtained from 1 is taken as the absorption rate.

The thickness of the barrier layer is preferably 10 nm or more, more preferably 20 nm or more, and particularly preferably 40 nm or more from the viewpoint of suppressing the reaction between the optical adjustment layer 13 and the pressure-sensitive adhesive layer 15. On the other hand, from the viewpoint of flexibility, 300 nm or less is preferable, 200 nm or less is more preferable, and 100 nm or less is particularly preferable.

The laminated body 1 may be provided with a plurality of barrier layers. For example, a barrier layer may be provided between the base film (the metal layer when the metal layer 12 is provided) and the optical adjustment layer 13.

<Adhesive layer>
The pressure-sensitive adhesive layer 15 is a layer made of a transparent pressure-sensitive adhesive.
The laminate 1 of the present embodiment can decorate the adherend member from the inside by being attached to the inside of the transparent adherend member (opposite the side to be visually recognized) via, for example, the adhesive layer 15. ..

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 15 is not particularly limited as long as it is a transparent pressure-sensitive adhesive. Either the agent and the polyether adhesive can be used alone or in combination of two or more. From the viewpoint of transparency, processability, durability and the like, it is preferable to use an acrylic pressure-sensitive adhesive.

The thickness of the pressure-sensitive adhesive layer 15 is not particularly limited, but it is preferably 100 μm or less, more preferably 75 μm or less, because it is possible to improve visible light transmission, film thickness accuracy, and flatness by making the pressure-sensitive adhesive layer 15 thinner. It is preferably 50 μm or less, and more preferably 50 μm or less.

The total light transmittance of the entire pressure-sensitive adhesive layer 15 is not particularly limited, but the value at an arbitrary visible light wavelength measured according to JIS K7361 is preferably 10% or more, more preferably 30% or more, and 50%. It is more preferably% or more. The higher the total light transmittance of the pressure-sensitive adhesive layer 15, the more preferable.

It is preferable that the pressure-sensitive adhesive layer 15 is protected by a release liner until it is attached to the adherend member.

<Other layers>
In addition to the above-mentioned base film 10, indium oxide-containing layer 11, metal layer 12, optical adjustment layer 13, barrier layer 14, and adhesive layer 15, the laminate 1 of the present embodiment can be used in addition to the above-mentioned base film 10, indium oxide-containing layer 11, metal layer 12, and adhesive layer 15 as long as the effects of the present invention are exhibited. , Other layers may be provided depending on the application.
For example, the laminate 1 of the present embodiment may be provided with a light-shielding layer having no visible light transmission on the surface of the base film 10 opposite to the side on which the optical adjustment layer 13 is formed. By providing the light-shielding layer, for example, when the laminate 1 of the present embodiment is used for decorating the housing of an electronic device, it is possible to prevent the circuit inside the housing from being visually recognized through the laminate 1. it can.
The material of the light-shielding layer is not particularly limited, and for example, the material exemplified as the material that can be used for the above-mentioned base film 10 can be colored black and used.
Further, even in the laminated body not provided with the light-shielding layer, by making the base film 10 light-shielding, the same effect as in the case of providing the light-shielding layer can be obtained.

<UV resistance and high temperature and humidity resistance>
One of the factors for advancing the reaction between the optical adjustment layer 13 and the pressure-sensitive adhesive layer 15 is ultraviolet rays, temperature, and humidity. By providing the barrier layer 14 in the laminate 1 of the present embodiment, the reaction between the optical adjustment layer 13 and the pressure-sensitive adhesive layer 15 proceeds even when exposed to ultraviolet rays or a high-temperature and high-humidity environment. Hateful. The laminate 1 of the present embodiment has ultraviolet resistance (difficulty in reacting the optical adjustment layer 13 and the adhesive layer 15 when exposed to ultraviolet rays) and high temperature and high humidity resistance (exposure to a high temperature and high humidity environment). The difficulty of reaction between the optical adjustment layer 13 and the pressure-sensitive adhesive layer 15) can be evaluated using, for example, a reflection spectrum.

For example, the reflection spectrum obtained by bonding the laminate 1 to a glass plate via the pressure-sensitive adhesive layer 15 and irradiating the laminate 1 with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate (hereinafter, “initial reflection”). After exposing the laminate 1 bonded to the glass plate to ultraviolet rays or a high-temperature and high-humidity environment, the laminate 1 is irradiated with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. By comparing the obtained reflection spectra (hereinafter, also simply referred to as "reflection spectrum after irradiation with ultraviolet rays" and "reflection spectrum after exposure to a high temperature and high humidity environment"), ultraviolet resistance and high temperature and humidity resistance can be obtained. Can be evaluated.

In the laminate according to the embodiment of the present invention, the laminate is bonded to a glass plate via the pressure-sensitive adhesive layer, and the laminate is irradiated with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. The obtained reflection spectrum and the laminated body bonded to the glass plate are irradiated with ultraviolet light through the glass plate for 24 hours, and then visible light having a wavelength in the range of 380 nm to 780 nm is emitted through the glass plate. It is preferable that the color difference ΔE calculated by using the reflection spectrum obtained by irradiating is 3 or less.
From the viewpoint of ultraviolet resistance, the laminate 1 preferably has a color difference ΔE of 3 or less, preferably 2.5 or less, calculated using the initial reflection spectrum and the reflection spectrum after irradiation with ultraviolet rays for 24 hours. Is more preferable, and 2 or less is further preferable.
^{The color difference ΔE is the L *} value ^{in the CIE-L *} a ^* b ^* display system before and after UV irradiation using the initial reflection spectrum, the reflection spectrum after 24-hour UV irradiation, and the relative spectral distribution of the CIE standard Illuminant D65. The a ^* and b ^* ^{values are obtained, and the color differences ΔL *} , Δa ^* , and Δb ^* before and after ultraviolet irradiation are obtained using these values, and these color differences are used to obtain the following formula.
ΔE = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^0.5

In the laminate according to the embodiment of the present invention, the laminate is bonded to a glass plate via the pressure-sensitive adhesive layer, and the laminate is irradiated with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. After holding the minimum wavelength in the obtained reflection spectrum and the laminate bonded to the glass plate in an environment of a temperature of 65 ° C. and a humidity of 90% for 500 hours, visible light having a wavelength in the range of 380 nm to 780 nm is emitted to the glass plate. It is preferable that the difference from the minimum wavelength in the reflection spectrum obtained by irradiating the laminated body through the laminate is 15 nm or less.
From the viewpoint of high temperature and high humidity resistance, the laminate 1 is exposed to a minimum wavelength in the initial reflection spectrum (wavelength when the reflectance becomes a minimum value; hereinafter also referred to as “bottom wavelength”) and a high temperature and high humidity environment for 500 hours. The difference from the minimum wavelength in the reflected spectrum after this is preferably 15 nm or less, more preferably 10 nm or less, and further preferably 5 nm or less.

<Radio wave transparency>
When the laminate 1 includes the metal layer 12, it is preferable that the metal layer 12 has a discontinuous structure to improve radio wave transmission as described above.
The radio wave transmission property of the laminated body 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 radio wave transmission attenuation in the microwave band (5 GHz) and the amount of radio 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. A laminate (metal glossy film) having excellent radio wave transmission in the wave band is also excellent in radio wave transmission in the frequency band of the millimeter wave radar.
The amount of radio wave transmission attenuation in the microwave band (5 GHz) of the laminate 1 of the present embodiment is preferably 10 [−dB] or less, more preferably 5 [−dB] or less, and 2 [−dB]. ] The following is more preferable. 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 metal layer 12 (when the indium oxide-containing layer 11 is provided, the sheet resistance of the indium oxide-containing layer 11 and the metal layer 12 as a laminate) also has a correlation with radio wave transmission.
The sheet resistance of the metal layer 12 (when the indium oxide-containing layer 11 is provided, the sheet resistance of the indium oxide-containing layer 11 and the metal layer 12 as a laminate) is preferably 100 Ω / □ or more, and in this case, microwaves. The amount of radio wave transmission attenuation in the band (5 GHz) is about 10 to 0.01 [−dB].
The sheet resistance of the metal layer 12 (when the indium oxide-containing layer 11 is provided, the sheet resistance of the indium oxide-containing layer 11 and the metal layer 12 as a laminate) is more preferably 200 Ω / □ or more, and more preferably 600 Ω / □ or more. Is more preferable, and 1000 Ω / □ or more is particularly preferable.
Sheet resistance can be measured by eddy current measurement according to JIS-Z2316-1: 2014.

The amount of radio wave transmission attenuation and sheet resistance are affected by the material and thickness of the metal layer 12. Further, when the 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.

<Difference between maximum and minimum reflectance>
The surface of the laminate 1 on the pressure-sensitive adhesive layer 15 side preferably has a difference of 30% or more between the maximum value and the minimum value of the reflectance in the wavelength range of 380 nm to 780 nm. When the difference between the maximum value and the minimum value of the reflectance is 30% or more, the appearance can be deeply colored. From the viewpoint of coloring intensity, it is more preferably 35% or more, and further preferably 40% or more. The upper limit of the difference between the maximum value and the minimum value of the reflectance is not particularly limited.

[Manufacturing of laminate]
The method for forming the indium oxide-containing layer 11 on the base film 10 is not particularly limited, and examples thereof include a vacuum vapor deposition method, a sputtering method, and an ion plating method. The sputtering method is preferable because the thickness can be strictly controlled even in a large area.

The forming method for forming the metal layer 12 on the base film 10 (on the indium oxide-containing layer 11 when the indium oxide-containing layer 11 is formed) is not particularly limited, and examples thereof include a vacuum deposition method and a sputtering method. Can be mentioned.

The method of forming the optical adjustment layer 13 on the base film 10 (on the metal layer 12 when the metal layer 12 is formed) is not particularly limited, but for example, a vacuum deposition method, a sputtering method, an ion plating method, and a coating method. And so on.

The method of forming the barrier layer 14 on the optical adjustment layer 13 is not particularly limited, and examples thereof include a vacuum deposition method, a sputtering method, an ion plating method, and a coating method.

The pressure-sensitive adhesive layer 15 can be formed by applying a pressure-sensitive adhesive composition to the barrier layer 14.
The pressure-sensitive adhesive composition can be applied using a conventional coater, for example, a gravure roll coater, a reverse roll coater, a kiss roll coater, a dip roll coater, a bar coater, a knife coater, a spray coater, or the like. The drying temperature is not particularly limited, but is preferably 40 ° C. to 200 ° C., more preferably 50 ° C. to 180 ° C., and particularly preferably 70 ° C. to 120 ° C. The drying time is also not particularly limited, but is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

[Use of laminate]
The laminated body 1 of the present embodiment is used, for example, by being attached to the inner surface (opposite side of the visible side) of the transparent adherend member. 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.

Applications of the members decorated with the laminate of the present embodiment include, for example, structural parts for vehicles, vehicle-mounted products, housings for electronic devices, housings for home appliances, structural parts, mechanical parts, and various automobile parts. , Electronic equipment parts, furniture, kitchen appliances and other household goods, medical equipment, building material parts, other structural parts and exterior parts. More specifically, in the case of vehicles, instrument panels, console boxes, door knobs, door trims, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seats, steering wheels. , ECU box, electrical components, engine peripheral parts, drive system / gear peripheral parts, intake / exhaust system parts, cooling system parts, etc. 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 specifically described with reference to Examples, but the present invention is not limited to these Examples.

<Manufacturing of laminates of Examples 1 to 3 and Comparative Example 1>
As the base film, a film in which a thermosetting resin having a thickness of 2000 μm was formed on one surface of a PET film (thickness 50 μm) manufactured by Mitsubishi Plastics Co., Ltd. was used.
First, an ITO target was attached to a DC magnetron sputtering apparatus, and sputtering was performed while introducing Ar gas to directly form an indium oxide-containing layer (ITO layer) having a thickness of 8 nm along 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 wt%.

Next, an aluminum (Al) target was attached to an AC sputtering apparatus (AC: 40 kHz), and a metal layer (Al layer) having a thickness of 30 nm was formed on the ITO layer by sputtering while introducing Ar gas. .. The obtained Al layer was a discontinuous layer. The temperature of the base film when forming the Al layer was set to 130 ° C. The method of measuring the thickness of the metal layer will be described later.

Then, an AC sputtering system (AC: 40 kHz) to attach the aluminum (Al) target, on the Al layer by sputtering while introducing a o ₂ gas barrier layer having a thickness of 10nm and (AlO _x layer) Formed. The temperature of the base film when forming the AlO _{x layer was set to 130 ° C.}

Next, a Si target (AC: 40 kHz) is attached to the AC sputtering device, and sputtering is performed while introducing _{O 2} gas and N ₂ gas to form a 170 nm optical adjustment layer (SiN _x layer) _{on the AlO x layer.} Formed. The temperature of the base film when forming the SiN _{x layer was set to −8 ° C.}

Next, a Si target (AC: 40 kHz) was attached to the AC sputtering apparatus, and sputtering was performed while introducing _{Ar gas and O 2} gas to form a 20 nm barrier layer (SiO ₂ _{layer) on the SiN x layer.} .. The temperature of the base film when forming the SiO _{2 layer was set to −8 ° C.}

Next, an adhesive layer (transparent adhesive sheet for optics, thickness 25 μm, manufactured by Nitto Denko KK, trade name “CS9861UAS”) was attached onto _{the SiO 2 layer to obtain the laminate of Example 1.}

Further, the laminates of Examples 2 and 3 were obtained in the same manner as in Example 1 except that the thickness of the _{SiO 2 layer was changed as shown in Table 1.}
Further, a laminate of Comparative Example 1 was obtained in the same manner as in Example 1 except that the pressure-sensitive adhesive layer was formed on the SiN _x _{layer without forming the SiO 2 layer.}

<Measuring method of metal layer thickness>
First, as shown in FIG. 2, a square region 3 having a side of 5 cm is appropriately extracted from the laminated body, and the center lines A and B of the vertical and horizontal sides of the square region 3 are divided into four equal parts. A total of five points "a" to "e" were selected as measurement points.
Next, a cross-sectional image (transmission electron micrograph (TEM image)) at each of the selected measurement points was measured, and a viewing angle region containing five or more metal particles was extracted from the obtained TEM image.
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 taken as the thickness (nm) of the metal layer.

<Measurement of sheet resistance>
For the laminates of Examples 1 to 3 and Comparative Example 1, a metal layer and an indium oxide-containing layer were formed by an eddy current measurement method in accordance with JIS-Z2316 using a non-contact resistance measuring device NC-80MAP manufactured by Napuson. When the sheet resistance of the laminated body was measured, it was 1 kΩ or more in each case.

<Evaluation of durability against temperature and humidity>
The laminates of Examples 1 to 3 and Comparative Example 1 were bonded to a glass plate via an adhesive layer. Then, it was placed in a high temperature and high humidity environment with a temperature of 65 ° C. and a humidity of 90%, and kept for 500 hours. The spectral reflectance was measured as follows before being placed in a high-temperature and high-humidity environment, 240 hours after the high-temperature and high-humidity environment, and 500 hours after the lapse.
In the measurement of the spectral reflectance, a spectrocolorimeter was used to irradiate the laminate with visible light having a wavelength in the range of 380 nm to 780 nm at intervals of 5 nm through the glass plate, and the spectral reflectance of the reflected light was measured. ..

Table 1 shows the minimum wavelength (bottom wavelength) and the maximum wavelength (peak wavelength) in the reflection spectrum in the wavelength range of 380 nm to 780 nm thus obtained.

Further, using the reflection spectrum in the wavelength range of 380 nm to 780 nm thus obtained and the relative spectral distribution of the CIE standard illuminant D65, the L ^* value and the a ^* value in the ^{CIE-L *} a ^* b ^{* display system are used.} , And b ^* values were calculated. Using these calculated values, the color difference between before being placed in a high-temperature and high-humidity environment (initial value) and when 240 hours have passed (after 240 hours) and 500 hours have passed (after 500 hours) since the high-temperature and high-humidity environment. ΔL ^* , Δa ^* , and Δb ^* were obtained, and the color difference ΔE was calculated using the following formula. The results are shown in Table 1.
ΔE = {(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² } ^0.5

In Comparative Example 1, the bottom wavelength of the reflection spectrum was shifted to the short wavelength side of 20 nm after being left in a high temperature and high humidity environment for 500 hours.
On the other hand, in Examples 1 to 3, there was no shift in the bottom wavelength and the peak wavelength of the reflection spectrum even after being left in a high temperature and high humidity environment for 500 hours, and the high temperature and high humidity durability was excellent.

<Manufacturing of Laminates of Examples 4 to 7 and Comparative Example 2>
The laminate of Example 4 was produced in the same manner as in Example 1 except that an _{Nb 2} O ₅ layer having a diameter of 150 nm _{was formed instead of the SiN x} layer as the optical adjustment layer. The Nb ₂ O ₅ layer was formed by attaching an Nb target (AC: 40 kHz) to an AC sputtering apparatus and sputtering while introducing _{Ar gas and O 2 gas.} The temperature of the base film when forming the Nb ₂ O _{5 layer was set to −8 ° C.}
Further, the laminates of Examples 5 and 6 were obtained in the same manner as in Example 4 except that the thickness of the _{SiO 2 layer was changed as shown in Table 2.}
Further, a laminate of Example 7 was obtained in the same manner as in Example 5 except that a 50 μm SiO ₂ layer was further formed between the AlO _x layer and the Nb ₂ O _{5 layer.} Table 50/50 "SiO ₂ layer thickness" column 2, the thickness of the SiO ₂ layer of two layers means that both are 50 [mu] m.
Further, a laminate of Comparative Example 2 was obtained in the same manner as in Example 4 except that the pressure-sensitive adhesive layer was formed on the _{Nb 2} O ₅ layer without forming _{the SiO 2 layer.}

<Measurement of sheet resistance>
When the sheet resistance of the laminates of Examples 4 to 7 and Comparative Example 2 was measured in the same manner as in Examples 1 to 3 and Comparative Example 1, they were all 1 kΩ or more.

<Evaluation of durability against ultraviolet light>
The laminates of Examples 4 to 7 and Comparative Example 2 were bonded to a glass plate via an adhesive layer. After that, it was put into a UV tester and held for 500 hours while irradiating the laminate with ultraviolet light through the glass plate. Before putting into the UV testing machine, at the time when 24 hours have passed, 240 hours have passed, and 500 hours have passed since being put into the UV testing machine, in the same manner as in Examples 1 to 3 and Comparative Example 1. The spectral reflectance was measured, and the minimum wavelength (bottom wavelength), maximum wavelength (peak wavelength), and ΔE were determined.
Before putting it in the UV testing machine, at the time when 240 hours have passed since it was put into the UV testing machine, and at the time when 500 hours have passed, the maximum and minimum wavelengths, and at the time when 24 hours have passed since it was put into the UV testing machine. ΔE is shown in Table 2.

In Comparative Example 2, ΔE was large after 24 hours had passed by irradiation with ultraviolet light.
On the other hand, in Examples 4 to 7, ΔE was small and the ultraviolet light durability was excellent even after 24 hours had passed after irradiation with ultraviolet light.

According to the present invention, it is possible to provide a laminate that can decorate an adherend member to give a colored appearance and further suppress changes in appearance due to various factors such as ultraviolet rays, temperature, and humidity. ..

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on September 30, 2019 (Japanese Patent Application No. 2019-179322), the contents of which are incorporated herein by reference.

1 Laminated body 10 Base film 11 Indium oxide-containing layer 12 Metal layer 12a Part 12b Gap 13 Optical adjustment layer 14 Barrier layer 15 Adhesive layer

Claims

A laminate including a base film, an optical adjustment layer, a barrier layer, and an adhesive layer in this order.
The optical adjustment layer is a layer having a refractive index of 1.75 or more containing at least one selected from the group consisting of metal oxides, metal nitrides, and metal sulfides.
The barrier layer is a layer containing a metal oxide and / or a metal nitride.
The pressure-sensitive adhesive layer is a laminated body which is a layer made of a transparent pressure-sensitive adhesive.
The laminate according to claim 1, further comprising a metal layer between the base film and the optical adjustment layer.
The laminate according to claim 2, wherein the metal layer includes a plurality of portions that are discontinuous with each other at least in part.
The laminate according to claim 2 or 3, further comprising an indium oxide-containing layer between the base film and the metal layer.
The laminate according to any one of claims 1 to 4, wherein the optical adjustment layer contains Si and / or Nb.
The laminate according to any one of claims 1 to 5, wherein the barrier layer contains SiO 2.
The laminate is attached to a glass plate via the pressure-sensitive adhesive layer, and the reflection spectrum obtained by irradiating the laminate with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate and the glass plate. A reflection spectrum obtained by irradiating the laminated body with ultraviolet light through the glass plate for 24 hours and then irradiating the laminated body with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. The laminate according to any one of claims 1 to 6, wherein the color difference ΔE calculated using the glass is 3 or less.
The laminated body is attached to a glass plate via the pressure-sensitive adhesive layer, and visible light having a wavelength in the range of 380 nm to 780 nm is irradiated to the laminated body through the glass plate to obtain a minimum wavelength in a reflection spectrum and the above. It is obtained by holding the laminate bonded to the glass plate in an environment of a temperature of 65 ° C. and a humidity of 90% for 500 hours, and then irradiating the laminate with visible light having a wavelength in the range of 380 nm to 780 nm through the glass plate. The laminate according to any one of claims 1 to 7, wherein the difference from the minimum wavelength in the reflection spectrum is 15 nm or less.