TW202003233A - Electromagnetic wave transmissive metallic luster product and metal thin film - Google Patents

Abstract

The present invention relates to an electromagnetic wave transmissive metallic luster product provided with a substrate and a metal layer formed on the substrate, wherein the metal layer has a maximum value of reflectivity within a range of 380-780 nm in a total light reflection spectrum.

Description

Electromagnetic wave transmissive metallic luster articles and metal films

The invention relates to an electromagnetic wave-transmitting metallic luster article and a metal film.

Conventionally, a member having electromagnetic wave permeability and metallic luster has both high-grade appearance and electromagnetic wave permeability from its metallic luster appearance, so it is suitable for a device that transmits and receives electromagnetic waves. For example, a cover member of a millimeter-wave radar mounted on the front part of a car such as a front grille, emblem, etc. is required to be decorated to have both brilliance and electromagnetic wave permeability Shiny metallic items.

The millimeter wave radar sends electromagnetic waves (frequency about 77GHz, wavelength about 4mm) at the millimeter wave frequency to the front of the car, receives the reflected waves from the target, measures and analyzes the reflected waves, thereby measuring the distance to the target or the direction of the target ,size. The measurement result can be used for workshop measurement, automatic speed adjustment, automatic brake adjustment, etc. The front part of a car equipped with such a millimeter-wave radar is a so-called car face, which gives a great influence to the user. Therefore, it is ideal to perform a high-level sense with a metallic gloss front decoration. However, in the case of using metal in the front part of the car, the transmission and reception of electromagnetic waves by millimeter-wave radar is practically impossible or hindered. Therefore, in order not to hinder the function of the millimeter-wave radar and not to damage the design of the car, it is necessary to have both metallic luster articles with both brightness and electromagnetic wave permeability.

Such metallic luster objects are not only millimeter-wave radars, but also various devices that need to be communicated, such as door handles for cars equipped with smart keys, electronic devices such as in-vehicle communication devices, mobile phones, and personal computers. look forward to. In addition, in recent years, with the development of IoT technology, applications in a wide range of fields, such as household appliances such as refrigerators that have not communicated and life appliances, have also been expected.

Regarding the metallic luster member, Japanese Patent Laid-Open No. 2007-144988 (Patent Document 1) discloses a resin product including a metal film made of chromium (Cr) or indium (In). This resin product includes: an inorganic base film including a resin base material and an inorganic compound formed on the resin base material, and the brightness and discontinuousness of the film formed by physical vapor deposition on the inorganic base film Structured metal film made of chromium (Cr) or indium (In). As an inorganic underlayer film, Patent Document 1 is a thin film using (a) a metal compound, for example, a titanium compound such as titanium oxide (TiO, TiO ₂ , Ti ₃ O _5, etc.); silicon oxide (SiO, SiO ₂ etc.), nitrogen Silicon compounds such as silicon oxide (Si ₃ N ₄ etc.); aluminum compounds such as aluminum oxide (Al ₂ O ₃ ); iron compounds such as iron oxide (Fe ₂ O ₃ ); selenium compounds such as selenium oxide (CeO); Zirconium compounds such as zirconia (ZrO); zinc compounds such as zinc sulfide (ZnS); (b) coating films of inorganic coatings, such as silicon, amorphous TiO _z, etc. (other metal compounds exemplified above) ) The coating film of inorganic paint as the main component.

On the other hand, Japanese Patent Laid-Open No. 2009-298006 (Patent Document 2) discloses that not only chromium (Cr) or indium (In), but also aluminum (Al), silver (Ag), and nickel (Ni) as metals Electromagnetic wave-transmitting bright resin product formed by a film. Japanese Unexamined Patent Publication No. 2010-5999 (Patent Document 3) describes that a metal film layer is formed on a base material sheet, and the base material sheet is subjected to heat treatment while being loaded with tension, thereby producing electromagnetic wave permeability with cracks The method of decorating the metal film with thin film. [Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2007-144988 [Patent Document 2] Japanese Patent Laid-Open No. 2009-298006 [Patent Document 3] Japanese Patent Laid-Open No. 2010-5999

(Problems to be solved by the invention)

However, the inventors found that the metallic luster articles of the prior art have a frequency characteristic, that is, each light wavelength and reflectance are different due to the reflection spectrum of the metal layer, so it is difficult to obtain a good metallic tone appearance. The invention of the present invention was developed in view of the above, and its object is to provide an electromagnetic wave-transmitting metallic luster article having a good metallic tone appearance. (Means to solve the problem)

In order to solve the above-mentioned problems, the present inventors have conducted an in-depth review and found that in an electromagnetic wave-transmitting metallic luster article provided with a metal layer, by controlling the wavelength indicating the maximum value of the reflectance of the total light reflection spectrum of the metal layer to Appropriate scope can solve the above problems.

The electromagnetic-wave-transmitting metallic luster article of the present invention includes a base and a metal layer formed on the base. The maximum value of the reflectance of the total light reflection spectrum of the metal layer is in the range of 380 nm to 780 nm.

In one aspect of the electromagnetic wave-transmitting metallic luster article of the present invention, the metal layer includes at least a part of a plurality of parts in a discontinuous state, and the average particle diameter of the plurality of parts is 100 to 500 nm.

In one aspect of the electromagnetic wave-transmitting metallic luster article of the present invention, an indium oxide-containing layer is further provided between the substrate and the metal layer.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, it is preferable that the indium oxide-containing layer is provided in a continuous state.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the indium oxide-containing layer includes any one of indium oxide (In ₂ O ₃ ), indium tin oxide (ITO), or indium zinc oxide (IZO) By.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the thickness of the indium oxide-containing layer is 1 nm to 1000 nm.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the thickness of the metal layer is 20 nm to 100 nm.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the ratio of the thickness of the metal layer to the thickness of the indium oxide-containing layer (thickness of the metal layer/thickness of the indium oxide-containing layer) may also be 0.02 ~100.

In one form of the electromagnetic-wave-transmitting metallic luster article of the present invention, the sheet resistance may be 100 Ω/□ or more.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the plural portions may be formed in an island shape.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the metal layer is aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or alloys thereof Whichever is ideal.

In one form of the electromagnetic wave-transmitting metallic luster article of the present invention, the substrate is preferably any one of a substrate film, a resin molded article substrate, a glass substrate, or an article to which metallic luster should be imparted.

The metal thin film of the present invention is a metal thin film formed on a substrate, The aforementioned metal thin film has a thickness of 20 nm to 100 nm, and the maximum value of the reflectance of the total light reflection spectrum is in the range of 380 nm to 780 nm.

An aspect of the metal thin film of the present invention includes at least a part of a plurality of island-shaped portions in a discontinuous state, and the average particle diameter of the plurality of island-shaped portions is preferably 100 to 500 nm.

In one form of the metal thin film of the present invention, the metal thin film is any one of aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or alloys of these Ideal. [Effect of invention]

According to the present invention, it is possible to provide an electromagnetic wave-transmitting metallic luster article having a good metallic tone appearance.

Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. In the following, for convenience of description, only suitable embodiments of the present invention are shown, but of course the present invention is not limited to this.

＜1. Basic structure＞ FIG. 1 shows a schematic cross-sectional view of an electromagnetic wave-transmitting metallic luster article (hereinafter referred to as "metallic luster article") 1 according to an embodiment of the present invention, and FIG. 3 shows a surface of a metallic luster article 1 according to an embodiment of the present invention. Photo of electron microscope (SEM portrait). In addition, FIG. 5 shows a transmission electron microscope photograph (TEM image) of the cross section of the island-shaped metal layer 11 according to an embodiment of the present invention.

The metallic luster article 1 includes a base 10 and a metal layer 12 formed on the base 10.

The metal layer 12 is formed on the base 10. It is desirable that the metal layer 12 include a plurality of portions 12a in a state in which at least a part is in a discontinuous state. These portions 12a of the metal layer 12 are at least partially in a discontinuous state, in other words, at least a portion is separated by a gap 12b. Once separated by the gap 12b, the sheet resistance of the metallic luster article increases, and the interaction with the radio wave decreases, so that the radio wave easily passes through. Each of these portions 12a may be an aggregate of sputtered particles formed by vapor-depositing or sputtering a metal. In addition, the configuration of the metal layer 12 is not limited to the configuration of the plural portions 12a in which at least a part is in a discontinuous state, and may be a continuous configuration as long as electromagnetic wave permeability can be ensured.

In addition, the "discontinuous state" in this specification means a state where they are separated from each other by the gap 12b, and as a result, they are electrically insulated from each other. By being electrically insulated, the sheet resistance of the metallic luster article becomes larger, and it is easy to obtain the desired electromagnetic wave permeability. That is, according to the metal layer 12 formed in a discontinuous state, it is easy to obtain sufficient brightness, and it is also easy to ensure electromagnetic wave permeability. The discontinuous form is not particularly limited, and includes, for example, an island structure and a crack structure. Here, the "island structure" is a structure in which metal particles are independent of each other as shown in FIG. 3, and these particles are slightly separated or partially in contact with each other.

The so-called crack structure is a structure in which a metal thin film is broken by cracks. The metal layer 12 of the crack structure can be formed, for example, by providing a metal thin film layer on the base film and bending and extending the crack to generate the metal thin film layer. At this time, there is a lack of stretchability between the base film and the metal thin film layer, that is, by providing a brittle layer made of a material that is likely to crack due to extension, the cracked metal layer 12 can be easily formed.

As described above, the form in which the metal layer 12 is discontinuous is not particularly limited, but from the viewpoint of productivity, the island-like structure is ideal.

The electromagnetic wave permeability of the metallic luster article 1 can be evaluated by, for example, the amount of attenuation of radio wave transmission. In the metallic luster article 1, the radio wave transmission attenuation in the microwave band (5 GHz) measured by the method described in the column of Examples is preferably 10 [-dB] or less, more preferably 5 [-dB] or less, 2 [- dB] The following is more ideal. If it is greater than 10 [-dB], there is a problem that 90% or more of the radio wave is blocked. In addition, there is a correlation between the radio wave transmission attenuation in the microwave frequency band (1 GHz) and the radio wave transmission attenuation in the millimeter wave radar frequency band (76-80 GHz). Because the values show relatively close values, the electromagnetic wave transmission in the microwave frequency band A good metallic luster article has good electromagnetic wave permeability in the millimeter wave radar band.

The sheet resistance of the metallic luster article 1 is also related to electromagnetic wave permeability. The sheet resistance of the metallic luster article 1 is preferably 100 Ω/□ or more. In this case, the attenuation of radio wave transmission in the microwave band (5 GHz) is about 10 to 0.01 [-dB]. The sheet resistance of metallic luster articles is more preferably 200Ω/□ or more, and more preferably 600Ω/□ or more. In addition, it is particularly desirable to be 1000 Ω/□ or more. Although the upper limit of the sheet resistance is not particularly limited, it is preferably 10 ¹⁵ Ω/□ or less. The sheet resistance of the metallic luster article 1 can be measured by an eddy current measurement method according to JIS-Z2316-1:2014.

The attenuation of radio wave transmission and the sheet resistance of the metallic luster article 1 are affected by the material, thickness, etc. of the metal layer 12. In addition, when the metallic luster article 1 includes the indium oxide-containing layer 11, it is also affected by the material, thickness, etc. of the indium oxide-containing layer 11.

＜2. Substrate＞ From the viewpoint of electromagnetic wave permeability, the substrate 10 may be resin, glass, ceramic, or the like. The substrate 10 may be any of 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 terephthalate (PEN), polybutylene terephthalate, polyamide, Individual polymers of polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene, polypropylene (PP), polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), ABS, etc. or Transparent film made of copolymer.

According to such components, there is no case that affects the brightness or the electromagnetic wave permeability. However, from the viewpoint of forming the indium oxide-containing layer 11 or the metal layer 12 later, those that can withstand high temperatures such as vapor deposition or sputtering are desirable. Therefore, among the above materials, for example, polyethylene terephthalate, poly It is ideal for ethylene dicarboxylate, acrylic acid, polycarbonate, cycloolefin polymer, ABS, polypropylene, polyurethane. Among them, polyethylene terephthalate or cycloolefin polymer, polycarbonate, and acrylic are ideal from the viewpoint of good balance between heat resistance and cost.

The base film may be a single-layer film or a laminated film. From the ease of processing and the like, the thickness is preferably about 6 μm to 250 μm, for example. In order to enhance the adhesion with the indium oxide-containing layer 11 or the metal layer 12, plasma treatment or easy adhesion treatment may also be applied. When the substrate 10 is a base film, the metal layer 12 may be provided on at least a part of the base film, or may be provided on only one side of the base film, or may be provided on both sides.

Here, it should be noted that the base film is only an example of an object (substrate 10) on which the metal layer 12 can be formed on the surface. The substrate 10 includes, in addition to the base film, the resin molded base material, the glass base material, and the article itself that should impart metallic luster as described above. Examples of the base material of the resin molded article and the articles to be given metallic luster include structural parts for vehicles, vehicle-mounted articles, housings of electronic appliances, housings of home appliances, structural parts, mechanical parts, and various automotive parts , Electronic equipment parts, furniture, kitchen supplies, etc., for household use, medical equipment, construction materials parts, other structural parts or exterior parts, etc.

The metal layer 12 may be formed on all of the substrates, may be formed on a part of the surface of the substrate, or may be formed on the entire surface of the substrate. In this case, it is desirable that the substrate 10 to be provided with the metal layer 12 conforms to the same materials and conditions as the above-mentioned base film.

<3. Indium oxide-containing layer> In addition, as shown in FIG. 2, the electromagnetic-wave-transmitting metallic luster article 1 of one embodiment may further include an indium oxide-containing layer 11 between the base 10 and the metal layer 12. The indium oxide-containing layer 11 may be provided directly on the surface of the base 10 or may be provided indirectly through a protective film provided on the surface of the base 10. The indium oxide-containing layer 11 is preferably provided in a continuous state on the surface of the substrate 10 to which metallic luster should be imparted, that is, without gaps. By providing in a continuous state, the smoothness or corrosion resistance of the indium oxide-containing layer 11, the further metal layer 12, or the electromagnetic wave-transmissive metallic luster article 1 can be improved, and the indium oxide-containing layer 11 can be easily formed without deviation in the plane.

If the indium oxide-containing layer 11 is further provided between the base 10 and the metal layer 12 in this way, that is, the indium oxide-containing layer 11 is formed on the base 10 and the metal layer 12 is formed thereon, it is easy to form in a discontinuous state The metal layer 12 is therefore ideal. The details of the mechanism are not necessarily clear, but it can be considered that when a thin film is formed on the substrate by sputtering particles of metal evaporation or sputtering, the surface diffusivity of the particles on the substrate will affect the shape of the thin film, and the temperature of the substrate is high. The metal layer has low wettability to the substrate, and the melting point of the material of the metal layer is low, so it is easy to form a discontinuous structure. Moreover, by providing an indium oxide-containing layer on the substrate, the surface diffusivity of the metal particles on the surface is promoted, and it is easy to grow the metal layer in a discontinuous state.

As the indium oxide-containing layer 11, indium oxide (In ₂ O ₃ ) itself may be used, or, for example, a metal-containing object such as indium tin oxide (ITO) or indium zinc oxide (IZO) may also be used. However, ITO or IZO containing the second metal is more ideal at the point where the discharge stability of the sputtering process is higher. By using such an indium oxide-containing layer 11, a continuous film can also be easily formed along the surface of the substrate, and in this case, the metal layer laminated on the indium oxide-containing layer can be easily formed into an island-like Continuous construction is therefore ideal. In addition, as will be described later, in this case, the metal layer contains not only chromium (Cr) or indium (In), but also various metals, such as aluminum, which are generally difficult to form a discontinuous structure and difficult to apply to this application.

The content ratio of the mass ratio of tin oxide (SnО ₂ ) contained in ITO (content ratio=(SnO ₂ /(In ₂ O ₃ +SnO ₂ ))×100) is not particularly limited, for example 2.5wt%~30wt% , More ideally 3wt% ~ 10wt%. The content ratio of the mass ratio of zinc oxide (ZnO) contained in IZO (content ratio=(ZnO/(In ₂ O ₃ +ZnO))×100) is, for example, 2 wt% to 20 wt%. The thickness of the indium oxide-containing layer 11 is generally preferably 1000 nm or less, more preferably 50 nm or less, and 20 nm or less from the viewpoint of sheet resistance, radio wave transmission attenuation, and productivity. On the other hand, in order to make the laminated metal layer 12 into a discontinuous state, 1 nm or more is preferable, and to form a discontinuous state reliably, 2 nm or more is more preferable, and 5 nm or more is more preferable.

＜4. Metal layer＞ The metal layer 12 is formed on the substrate 10, and the maximum value of the reflectance of the total light reflection spectrum is in the range of 380 nm to 780 nm. In addition, the metal layer 12 includes plural portions 12a in which at least a part is in a discontinuous state, and the average particle diameter of the plural portions 12a is preferably 100 to 500 nm. Here, the average particle diameter of the plural part 12a means the average value of the diameter of the plural part 12a corresponding to the circle. The diameter corresponding to the circle of the plural part 12a is the diameter of a complete circle corresponding to the area of the plural part 12a. The average particle diameter of the plural part 12a can be measured by the method described in the column of Examples.

In order for the metal layer 12 to exhibit a good metallic tone appearance, the maximum value of the reflectance of the total light reflection spectrum of the metal layer 12 is ideally located around the visible light field. In addition, in the following total light reflection spectrum, the wavelength at which the reflectance becomes maximum is referred to as "reflection peak wavelength". If the reflection peak wavelength of the metal layer 12 is too short, the metallic luster article 1 can be seen bluish. On the contrary, if the reflection peak wavelength is too long, the metallic luster article 1 can be seen reddish. Good metallic tone appearance. In the present invention, the reflection peak wavelength of the metal layer 12 is set in the range of 380 nm to 780 nm, whereby a good metallic tone appearance can be obtained. The reflection peak wavelength of the metal layer 12 is more preferably 400 nm to 700 nm.

The reflection peak wavelength of the metal layer 12 varies depending on the material or structure of the metal layer. When the metal layer 12 includes at least a part of the plural portions 12a in a discontinuous state, the reflection peak wavelength of the metal layer 12 varies depending on the average particle diameter of the plural portions 12a, if the average particle diameter of the plural portions 12a The smaller the reflection peak wavelength is, the larger the average particle diameter of the plural part is, and the longer the reflection peak wavelength tends to be. When the metal layer 12 includes at least a part of the plural portions 12a in a discontinuous state, in order to achieve the above-mentioned appropriate reflection peak wavelength, the average particle diameter of the plural portions 12a is ideally set to 100 to 500 nm, and is set to 150 nm ~450nm is more ideal.

In addition, the distance between the parts 12a is not particularly limited, but it is usually about 10 to 1000 nm.

Of course, the metal layer 12 can exert sufficient brilliance, and it is preferable that the melting point is relatively low. This is because the metal layer 12 is formed by growing a thin film using sputtering. For this reason, it is suitable as the metal layer 12 to be a metal having a melting point of about 1000° C. or less, for example, selected from aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), and silver (Ag) Any one of at least one kind of metal and an alloy containing the metal as a main component are ideal. In particular, Al and these alloys are ideal for reasons such as the brightness, stability, and price of the substance. In addition, when an aluminum alloy is used, the aluminum content is preferably 50% by mass or more.

The thickness of the metal layer 12 is such that it exhibits sufficient brilliance, and is usually preferably 20 nm or more. On the other hand, from the viewpoint of sheet resistance or radio wave transmission attenuation, it is usually 100 nm or less. For example, 20nm~100nm is ideal, and 30nm~70nm is more ideal. This thickness is suitable for forming a uniform film with good productivity, and the appearance of the resin molded product of the final product is also good. In addition, the thickness of the metal layer 12 can be measured as follows, for example. (Measurement method of thickness of metal layer) First, from the metallic luster article, as shown in FIG. 4, a square field 3 with a side of 5 cm is properly extracted, and the center line A and B of the vertical and horizontal sides of the square field 3 are respectively divided into 4 equal parts. Five points "a" to "e" obtained in total are used as measurement points. Next, a cross-sectional image (transmission electron microscope photograph (TEM image)) of each selected measurement site as shown in FIG. 5 is measured, and a field of view angle field including five or more metal portions 12a is extracted from the obtained TEM image. The total cross-sectional area of the metal layer in the viewing angle area extracted at each of the five measurement positions by the width of the viewing angle area is defined as the thickness of the metal layer in each viewing angle area, and each of the five measurement positions The average value of the thickness of the metal layer in each viewing angle area is defined as the thickness of the metal layer.

In addition, for the same reason, the ratio of the thickness of the metal layer 12 to the thickness of the indium oxide-containing layer 11 (the thickness of the metal layer 12/the thickness of the indium oxide-containing layer 11) is preferably in the range of 0.1 to 100, and 0.3 to 35 The range is more ideal.

In addition to the above-mentioned metal layer and the indium oxide-containing layer, the metallic luster article of this embodiment may be provided with other layers according to the application. Examples of other layers include optical adjustment layers (color adjustment layers) such as high-refractive materials for adjusting the appearance of colors, etc., and protective layers (scratch resistance) for improving durability such as moisture resistance and scratch resistance. Layer), barrier layer (corrosion prevention layer), easy adhesion layer, hard coat layer, antireflection layer, light extraction layer, anti-glare layer (anti-glare) layer, etc.

＜5. Manufacture of metallic luster articles＞ An example of the manufacturing method of the metallic luster article 1 will be described. Although not specifically described, the case of substrates other than the base film 10 is also produced in the same manner.

When the metal layer 12 is formed on the base 10, for example, a method such as vacuum deposition or sputtering can be used.

In addition, when the indium oxide-containing layer 11 is formed on the substrate 10, before the formation of the metal layer 12, the indium oxide-containing layer 11 is formed by vacuum evaporation, sputtering, ion plating, or the like. However, the thickness can be strictly controlled from a large area, and sputtering is ideal.

In addition, when the indium oxide-containing layer 11 is provided between the base 10 and the metal layer 12, it is desirable that direct contact be made without interposing other layers between the indium oxide-containing layer 11 and the metal layer 12.

<6. Metal film> The metal thin film of this embodiment is a metal thin film formed on a substrate. The metal thin film has a thickness of 20 nm to 100 nm. The maximum value of the reflectance of the total light reflection spectrum is in the range of 380 nm to 780 nm. In addition, the metal thin film of the present embodiment includes plural island-shaped portions at least partially in a discontinuous state, and the average particle diameter of the plural island-shaped portions is preferably 100 to 500 nm. The above-mentioned metal layer 12 can also be formed to a thickness of 20 nm to 100 nm, and only this is used as the metal thin film. For example, the metal layer 12 is formed by sputtering on the indium oxide-containing layer 11 laminated on a substrate such as a base film to obtain a thin film with a metal thin film. In addition, an adhesive is applied to the substrate to prepare a substrate with an adhesive layer. The metal film-attached film and the substrate with the adhesive layer are attached in such a way that the metal layer 12 and the adhesive layer will be in contact, and the film and substrate are peeled off after being sufficiently adhered, thereby making it possible to exist in the metal-attached film The metal layer (metal film) 12 on the outermost surface of the thin film is transferred to the outermost surface of the substrate with the adhesive layer. As for the average particle diameter of the substrate, the metal thin film, and the plural portions, the above description can be invoked.

＜7. Use of metallic luster articles and metal films＞ Since the metallic luster article 1 and the metal thin film of the present embodiment have electromagnetic wave permeability, it is desirable to use devices, articles, and parts for transmitting and receiving electromagnetic waves. Examples include structural parts for vehicles, vehicle-mounted articles, housings of electronic devices, housings of home appliances, structural parts, mechanical parts, various automotive parts, parts for electronic devices, furniture, kitchen appliances, etc. Trends in use, medical equipment, parts of construction materials, other structural parts or exterior parts, etc. More specifically, in terms of vehicle relations, there are dashboards, central storage boxes, door handles, door trims, gear levers, pedals, glove boxes, bumpers, hoods, mudguards, and rear luggage Boxes, doors, roofs, pillars, seats, steering wheels, ECU boxes, electrical components, engine peripheral parts, drive system/gear peripheral parts, air intake/exhaust system parts, cooling system parts, etc. Examples of electronic appliances and household appliances include refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting appliances, electric water heaters, televisions, clocks, ventilating fans, projectors, and lifters. , Mobile phones, smart phones, digital cameras, tablet PCs, portable music players, portable game consoles, chargers, batteries and other electronic information equipment. [Example]

Hereinafter, the present invention will be described more specifically with examples and comparative examples. The metallic luster articles of Examples 1 to 7 and Comparative Examples 1 to 3 were prepared, and the average particle diameter, reflection peak wavelength, glossiness, thickness of the metal layer (film thickness), and sheet resistance of the plural parts constituting the metal layer were measured. In addition, a base film is used as the base 10. The gloss of 20° is an evaluation of the brightness, and it is preferably large. The details of the evaluation method are as follows.

(1) Average particle size Using a scanning electron microscope (SEM), an SEM image of 50,000 times the area of 1.92 μm×2.56 μm of the metal layer of the metallic luster article was obtained. The area V of each part was obtained from the obtained SEM image, and the particle size R of each part was obtained from R=2×(V/π) ^0.5 , and the average value was used as the average particle size of the plural part. In addition, when calculating the average value, those with R of 0.05 μm or less are ignored as noise. An example of the obtained SEM image is shown in FIG. 3. 3 is an SEM image of the metal layer of the metallic luster article of Example 3. FIG.

(2) Reflection peak wavelength A black tape was attached to the base side of the metallic luster article, the surface of the metal layer side was irradiated with light, and a spectrum of total light reflected light was obtained using a spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation). Secondly, in the acquired spectrum, the wavelength with the maximum reflectance is detected in the wavelength range of 200 nm to 2000 nm as the reflection peak wavelength.

(3) 20° gloss A black tape was attached to the base side of the metallic luster article, and the 20° gloss was measured in accordance with JIS Z 8741 (1997 edition). Specifically, PG-IIM (manufactured by Nippon Denshoku Industries Co., Ltd.) was used for the measurement. In addition, the measurement of 20° glossiness was performed on the surface on the metal layer side. Based on the obtained gloss value, the brightness of the metallic luster article was judged based on the following criteria. (Evaluation criteria for brightness) Over 1000: ○ (good) 500~1000: △ (slightly bad) Under 500: × (bad) (4) Thickness of metal layer (film thickness) Using a transmission electron microscope (TEM), the thickness (film thickness) of the metal layer was measured by the aforementioned method. (5) Thin film resistor Using a non-contact resistance measuring device NC-80MAP (upper measurement limit: 3000 Ω/□) manufactured by Napson Corporation, in accordance with JIS-Z2316, the sheet resistance as a laminate of a metal layer and an indium oxide-containing layer was measured by an eddy current measurement method.

The evaluation results are shown in Table 1 below.

[Example 1] A PET film (thickness 38 μm) manufactured by Mitsubishi Resin Co., Ltd. was used as the base film. First, by DC magnetron sputtering, an ITO layer with a thickness of 5 nm was directly formed on the surface of the substrate film. The temperature of the base film when forming the ITO layer was set to 130°C. The content rate of tin oxide (SnО ₂ ) contained in ITO (content rate=(SnO ₂ /(In ₂ O ₃ +SnO ₂ ))×100) is 10 wt%.

Next, an alternating current sputtering (AC: 40 kHz) was used to form an aluminum (Al) layer on the ITO layer to obtain a metallic luster article (metal thin film). The temperature of the base film when forming the Al layer was set to 130°C.

[Examples 2-7, Comparative Examples 1-3] Except for changing the sputtering time when the aluminum (Al) layer is formed on the ITO layer, in the same manner as in Example 1, metallic luster articles (metal thin films) of Examples 2 to 7 and Comparative Examples 1 to 3 were obtained.

The metallic luster articles of Examples 1 to 7 all have good brilliance and exhibit an excellent metallic tone appearance. On the other hand, in the metallic luster articles of Comparative Examples 1 and 2, the average particle diameter of the plural parts of the metal layer is small, the reflection peak wavelength is short, the bluish appearance is exhibited, the gloss is small, and the brightness is poor. In addition, the metallic luster article of Comparative Example 3 has a plurality of portions of the metal layer having a large average particle diameter, a long reflection peak wavelength, a reddish appearance, low gloss, and poor brightness.

In addition, for metals other than aluminum (Al), which are particularly used in the above examples, metals with relatively low melting points such as zinc (Zn), lead (Pb), copper (Cu), and silver (Ag) can also be considered. Use the same method to form a discontinuous structure.

The present invention is not limited to the foregoing embodiments, and may be appropriately modified and embodied without departing from the gist of the invention.

In the above, the preferred embodiment of the present invention has been described, but the present invention is not limited to the above-mentioned embodiment, and various modifications and substitutions can be added to the above-mentioned embodiment without departing from the scope of the present invention. In addition, this case is based on the Japanese patent application filed on April 23, 2018 (Japanese Patent Application 2018-082657) and the Japanese patent application filed on April 22, 2019 (Japanese Patent Application 2019-080636). It is used as a reference in this case. [Industry use possibility]

The metallic luster article of the present invention is a device or article that can be used to transmit and receive electromagnetic waves, its parts, and the like. For example, it can also be used in structural parts for vehicles, vehicle-mounted articles, housings for electronic appliances, housings for household appliances, structural parts, mechanical parts, various automotive parts, electronic parts, furniture, kitchen appliances, etc. The home-oriented use, medical equipment, parts of construction materials, other structural parts or exterior parts, etc., are required for both design and electromagnetic wave permeability.

1‧‧‧Metal shiny items 10‧‧‧Matrix 11‧‧‧Indium oxide-containing layer 12‧‧‧Metal layer 12a‧‧‧Part 12b‧‧‧Gap

FIG. 1 is a schematic cross-sectional view of an electromagnetic wave-transmitting metallic luster article according to an embodiment of the present invention. 2 is a schematic cross-sectional view of an electromagnetic wave-transmitting metallic luster article according to an embodiment of the present invention. 3 is an electron microscope photograph of the surface of an electromagnetic wave-transmitting metallic luster article according to an embodiment of the present invention. 4 is a diagram for explaining a method for measuring the film thickness of a metal layer of an electromagnetic wave-transmitting metallic luster article according to an embodiment of the present invention. 5 is a diagram showing a transmission electron microscope photograph (TEM image) of a cross section of a metal layer according to an embodiment of the present invention.

1‧‧‧Metal shiny items

10‧‧‧Matrix

12‧‧‧Metal layer

12a‧‧‧Part

12b‧‧‧Gap

Claims (15)

An electromagnetic wave-transmissive metallic luster article, characterized by having a base and a metal layer formed on the base, The maximum value of the reflectance of the total light reflection spectrum of the metal layer is in the range of 380 nm to 780 nm. For example, the electromagnetic wave-transmitting metallic luster article of claim 1 of the patent application, wherein the metal layer includes at least a plurality of parts in a discontinuous state, The average particle diameter of the aforementioned plural parts is 100 to 500 nm. For example, as for the electromagnetic wave-transmitting metallic luster article in the second item of the patent application range, the plural parts are formed into an island shape. The electromagnetic wave-transmitting metallic luster article as described in any one of claims 1 to 3, further comprising an indium oxide-containing layer between the substrate and the metal layer. For example, the electromagnetic wave-transmitting metallic luster article of claim 4 of the patent application, wherein the aforementioned indium oxide-containing layer is provided in a continuous state. An electromagnetic wave-transmitting metallic luster article as claimed in item 4 or 5 of the patent application, wherein the aforementioned indium oxide-containing layer includes indium oxide (In ₂ O ₃ ), indium tin oxide (ITO) or indium zinc oxide (IZO ). The electromagnetic wave-transmitting metallic luster article as described in any of items 4 to 6 of the patent application range, wherein the thickness of the indium oxide-containing layer is 1 nm to 1000 nm. The electromagnetic wave-transmitting metallic luster article described in any one of items 1 to 7 of the patent application range, wherein the thickness of the metal layer is 20 nm to 100 nm. An electromagnetic wave-transmitting metallic luster article as described in any of items 4 to 7 of the patent application range, in which the ratio of the thickness of the metal layer to the thickness of the indium oxide-containing layer (thickness of the metal layer/containing The thickness of the indium oxide layer) is 0.02~100. An electromagnetic wave-transmitting metallic luster article as described in any of items 1 to 9 of the patent application range, in which the sheet resistance is 100 Ω/□ or more. An electromagnetic wave-transmitting metallic luster article as described in any of items 1 to 10 of the patent application range, wherein the metal layer is aluminum (Al), zinc (Zn), lead (Pb), copper (Cu) , Silver (Ag), or any of these alloys. The electromagnetic wave-transmitting metallic luster article as described in any one of claims 1 to 11, wherein the substrate is a base film, a resin molded article base, a glass base, or an article that imparts metallic luster Any of them. A metal thin film is a metal thin film formed on a substrate. The metal thin film has a thickness of 20 nm to 100 nm. The maximum value of the reflectance of the total light reflection spectrum is in the range of 380 nm to 780 nm. For example, the metal thin film of claim 13 includes at least a part of a plurality of island-shaped portions in a discontinuous state, and the average particle diameter of the plurality of island-shaped portions is 100 to 500 nm. For example, the metal thin film of claim 13 or 14, wherein the metal thin film is aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver (Ag), or alloys thereof Any of them.

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